The frequency converter is a device that converts a commercial power supply (50 Hz or 60 Hz) into an AC power of various frequencies to realize a variable speed operation of the motor, wherein the control circuit completes control of the main circuit, and the rectifier circuit converts the alternating current into direct current, The DC intermediate circuit smoothes the output of the rectifier circuit, and the inverter circuit reverses the DC power to AC power.
AC frequency conversion speed regulation technology is an important development direction of modern electric drive technology. With the application of power electronics technology, microelectronic technology and modern control theory in AC speed control system, frequency conversion AC speed regulation has gradually replaced the past slip speed regulation. Speed ​​control systems such as variable pole speed regulation and DC speed regulation are widely used in many fields of industrial production and daily life. However, due to the use environment, age, and some factors of human operation, the service life of the inverter is greatly reduced, and various faults occur in use.
1 . Static test results of the inverter to determine the fault
First, a static test can be done on the inverter. The general-purpose inverter generally includes the following parts: (1) rectifier circuit; (2) DC intermediate circuit; (3) inverter circuit; (4) control circuit.
The static test is mainly a test of the high-power transistor (power module) of the rectifier circuit, the DC intermediate circuit and the inverter circuit part, and the tool is mainly a multimeter. The rectifier circuit mainly tests the forward and reverse of the rectifier diode to judge whether it is good or bad. Of course, we can also test it with a withstand voltage gauge. The DC intermediate circuit is mainly for measuring the capacity and withstand voltage of the filter capacitor. We can also observe whether the safety valve on the capacitor is popped open, whether there is leakage or not.
To judge whether it is good or bad. The quality of the power module is judged mainly by the judgment of the freewheeling diode in the power module. For the IGBT module, we also need to judge whether it can be turned on and off in the presence of a trigger voltage.
2. Determine the location of the fault by the display of the inverter
(1) OC. Overcurrent fault This may be the most common fault in the inverter. First, troubleshoot due to parameter problems should be eliminated. For example, current limitation, too short acceleration time may lead to overcurrent. Then we have to judge whether the current detection circuit is faulty. Take the FVR075G7S-4EX as an example: We sometimes see that the FVR075G7S-4EX will have a current display when the motor is not connected. Where does the current come from? At this time, we must test its three Hall sensors. In order to determine the damage of the phase sensor, we can open the machine once every phase sensor is removed to see if there is an overcurrent display. After this test, it can basically be eliminated. OC failure.
(2) OV. Overvoltage faults must first eliminate faults caused by parameter problems. For example, the deceleration time is too short, and the overvoltage caused by the regenerative load, etc., then we can look at whether there is a problem with the input side voltage. Finally, we can look at whether the voltage detection circuit has a fault, the voltage sampling of the general voltage detection circuit. Points are the voltages of the intermediate DC link. Let's take Sanken SVF303 as an example. It is sampled by DC loop (DC of about 530V) and is stepped down by a large resistor. It is isolated by optocoupler. When the voltage exceeds a certain value, it shows “5†overvoltage ( This machine is a digital tube display.) We can see if the resistance is oxidized and the optocoupler has a short circuit.
(3) UV. Undervoltage We can first look at the input side voltage for a problem, then look at the voltage detection circuit, fault diagnosis and overvoltage are the same.
4) FU. Fast-Fuse Faults Most of the currently available inverters have introduced the fast-fuse fault detection function. (especially high-power inverters) Take the LG030IH-4 inverter as an example. It mainly samples and detects the voltage behind the fast-melting front. When the fast-melting damage is inevitable, there will be no voltage at the fast-melting end. At this time, the isolated optocoupler acts and a FU alarm occurs. Replacing the fast melt can solve the problem. In particular, it should be noted that it is necessary to judge whether there is a problem with the main circuit before replacing the fast melt.
(5) OH. Main cause of overheating The internal heat dissipation of the inverter is not good. We can check the cooling fan and ventilation channel.
(6) SC. Short circuit fault We can check if there is a short circuit inside the inverter. Detecting the internal circuit may not necessarily have a short circuit. At this time, we can detect that the power module may be faulty. If the drive circuit is normal, replace the power module and it should be able to repair the machine.
There are many kinds of faults in the inverter. The maintenance workers in the first steelmaking workshop have a late contact, and little is known about the basic knowledge of the inverter. We can only sum up in practice and find a quick and effective way to deal with the fault of the inverter. Method.
one. Basic knowledge of the main principles of the inverter.
After the three-phase 380V grid voltage is input from the L1, L2, L3 input terminals of the inverter, it must first be rectified by the rectifier bridge of the inverter, and then filtered by the capacitor to output a DC voltage of about 530V (this 530V is also commonly used. To judge the most common test point of the rectification part of the inverter, of course, the rectifier bridge is initially subjected to the power failure test) and then through the inverter circuit, by controlling the on/off of the inverter circuit to output the voltage of the appropriate frequency we want. (The most important thing about inverter frequency conversion is to control the shutdown of the inverter circuit to control the output frequency.) There are countless kinds of inverter faults. Fortunately, the inverters tend to be intelligent now, and the general faults can detect them themselves. The code is displayed on the control panel, and the user only needs to check the user manual to determine the cause of the failure. However, sometimes, when the inverter is running or starting up or when loading, the indicator light does not light up, the fan does not turn, and there is no output. At this time, we beginners do not know what to do. In fact, it is very simple, we just need to break the power supply of the inverter. Power off test its rectifier part and inverter part, in most cases, you can know the fault. There is one point to pay attention to here. It can't be measured immediately after power off. Because there are large capacitors in the inverter with hundreds of volts of high voltage, be sure to wait ten minutes and then measure. This should be noted. Test the rectifier bridge and inverter circuit before the inverter is powered on. The specific measurement methods are as follows:
Find the “+†and “-†of the DC output of the inverter, then adjust the multimeter to the measuring diode. The black meter is connected to “+â€. The red meter is connected to the input terminals L1, L2, L3 of the inverter and the rectifier bridge. If the half bridge is intact, the multimeter should display a pressure drop of 0.3... If the meter is damaged, the multimeter will display a "1" overrange. Instead, connect the red test lead to the "-" black test lead to L1, L2, L3 end to get the same result above. If "1" appears, the rectifier bridge is damaged. Then test its inverter circuit, the method is as follows: adjust the multimeter to the resistor & TImes; 10 files will connect the black meter to the "+" red meter to the output of the inverter U, V, W should have several ohms of resistance, reverse It should be infinite. Conversely, the red test lead is connected to the "-" to repeat the above process, and the same result should be obtained. In this way, when the measurement determines that the rectification part and the inverter part of the inverter are intact, the DC output of the inverter is measured to see if there is about 530V high voltage. Note that sometimes the multimeter displays tens of volts. Everyone thinks that the rectifier circuit works. In fact, it does not work. It will output a high voltage of about 530V in normal operation, and the voltage of several tens of volts is induced inside the inverter. If there is no high voltage around 530V, there is always a problem with the power supply. Some inverters are caused by a small chip resistor of the power supply board being burned, resulting in the power board not working, so that the inverter has no display and no output, the fan does not turn, and the indicator light does not light. In this way, it is possible to initially determine which part of the inverter has failed, and then focus on testing the suspected fault part when disassembling the machine.
(1) Basic terms
1, Electronic Line ShafTIng---ELS, many industrial production lines are composed of multiple machines, and each axis has a motion relationship. In the past, mechanical mechanisms were used to connect the shafts. If the shafts were connected electronically, and each state had its own drive motor, it was called "Electronic Line ShafTIng" (ELS). 2, Auto Tuning, a technology commonly used in magnetic flux vector inverters, can automatically monitor (find) motor parameters such as slip frequency / field current / torque current / stator impedance / rotor impedance / Stator inductance / rotor inductance and so on. With these parameters, you can make [Special Data Estimation] and [Slip (Slip) Compensation]. Also because of this technology, good operation accuracy can be obtained without the operation of the encoder.
3, no encoder operation, in the speed control, compared with the open loop of the old variable frenquency inverter, the magnetic flux vector inverter internally achieves a closed loop by the speed observation calculation function. Good speed accuracy can be achieved without the encoder on the motor side. The operation without encoder has the following advantages: 1), fine wiring; 2), no need to worry about the influence of RF noise on the low voltage signal of the encoder; 3), in the case of multiple vibrations, there is no need to worry about the high failure rate of the encoder.
4. The vector control of the inverter is in the AC motor, and the rotor generates a magnetic field by the induced current of the stator winding. The stator current has two parts. One part affects the magnetic field and the other part affects the motor output torque. To use an AC motor where speed and torque control are required, it is necessary to be able to separate the current that affects the torque, and the beam vector control can separate the two parts for independent control. (The physical quantity with size and direction is called a vector)
5, Field WeakeningField Weakening line can be used to weaken the field current of the motor, change the balance with the magnetic field, and make the motor run above the basic speed.
6. When the torque required for constant torque application does not change due to speed, it is often used in [fixed torque application]. Such as conveyor belt and other loads. [Constant Torque Application] Usually requires a large starting torque. [Constant torque application] It is easy to have motor heating problem at low speed operation. The solution is best: (1) increase the motor power; (2) use the inverter-specific motor with fixed speed cooling (ie, the motor cooling method). To force air cooling).
7, variable torque applications are more common in centrifugal loads, such as pumps / fans / fans, etc., the purpose of using the inverter is generally energy-saving. For example, when the fan is running at 50% speed, the required torque is less than that required for full speed operation. The variable torque inverter can only give the torque required by the motor to achieve energy saving. A brief peak load in a secondary application usually does not require additional energy to the motor. Therefore, the overload capability of the variable torque converter can be applied to most applications.
*The torque (current) capability of the fixed torque converter must be 150%/1minute of the rated value, while the overload (current) capability of the variable torque converter only needs to be rated at 120%/1minute. Because of centrifugal mechanical use Rarely exceeds the rated current. In addition, the starting torque required for variable torque applications is also smaller than the fixed torque.
8, inverter dedicated motor
The so-called [Inverter-duty Motor], the main features are as follows: 1), separate type of force ventilation (it is air-cooled); 2), 10Hz-60Hz is the fixed torque output; 3), high starting torque; 4), Low noise; 5), the motor is equipped with an encoder. * But not all motors known as inverter-specific motors have the above features.
9, on the speed:
1) Speed ​​regulation: adjust the running speed of the equipment according to the working conditions to achieve energy saving, reducing wear and on-demand production. 2) DC Controler/motor: The DC controller is used to adjust the DC motor to achieve the adjustment speed. 3) AC inverter/motor: The three-phase alternating current of the inverter output frequency changes to control the speed of the AC motor. 4) Vector vector inverter: Through complex calculation and transformation, the AC inverter controls the AC motor according to the control mode of the DC motor, thus achieving precise speed control, torque control, and improved output torque. 5) Servo control system: Introduce speed feedback or position feedback components in the motion system to achieve extremely precise speed control, positioning control and high dynamic response through the action of negative feedback.
10, several common industrial components:
1) Tacho-generator: A speed measuring component with alternating current and direct current. 2) Resolver: An economical and accurate speed and angular displacement measuring component.
3) Optical encoder (Encoder): A precise angular displacement, rotational speed measuring component suitable for use as a feedback component in position control systems.
4) PLC: Industrial calculation and control device, realize logic, timing, calculation and other control functions, generally as the upper host of the entire automation control system.
5) HMI (Human-Machine Interface): Human-machine interface.
6) Field-Bus System: A serial communication bus system applied to the industrial control field, which greatly reduces the wiring cost and improves the anti-interference ability of the control.
7) Distributed control: Different from the traditional centralized control, it emphasizes the intelligence of each node device. Generally, the sub-devices are connected by the field bus system. Greatly improve the flexibility and reliability of the system application, and reduce the computing burden of the host computer.
11, three terms on the motor: 1) ProtecTIon Code: (IP**) to examine the ability of a device to prevent foreign matter from entering and waterproofing, making one of the IEC standards. The two numbers represent the ability to prevent foreign objects and water resistance, respectively. The higher the value, the more small objects can be prevented from entering and subject to more intense water flow impact. Generally, IP54 (dustproof, anti-splashing water) equipment with the above protection level can be directly applied to the open air. 2) Insulation Grade: It is one of the IEC standards to examine the ultimate temperature rise capability of an electrical equipment (generally for a motor) under the premise of ensuring good insulation properties. There are generally Class B (85 degrees), Class F (105 degrees), and Class H (125 degrees).
3) Work system.
three. Introduction to knowledge1. What is a frequency converter?
The frequency converter is a power control device that converts the power frequency power source into another frequency by using the on/off function of the power semiconductor device.
2. What is the difference between PWM and PAM?
PWM is an abbreviation of English Pulse Width Modulation, which changes the pulse width of a pulse train according to a certain rule to adjust the output value and waveform. PAM is the abbreviation of Pulse Amplitude Modulation in English. It is a modulation method that changes the pulse amplitude of pulse train according to a certain rule to adjust the output value and waveform.
3. What is the difference between voltage type and current type?
The main circuit of the inverter can be roughly divided into two types: the voltage type is a frequency converter that converts the direct current of the voltage source into an alternating current, the filtering of the direct current circuit is a capacitor, and the current type is a frequency converter that converts the direct current of the current source into an alternating current. Its DC loop filter stone inductor.
4. Why does the voltage and current of the inverter change in proportion?
The torque of the asynchronous motor is generated by the interaction between the magnetic flux of the motor and the current flowing in the rotor. At the rated frequency, if the voltage is constant and only the frequency is reduced, the magnetic flux is too large, and the magnetic circuit is saturated. The motor will be burned. Therefore, the frequency and voltage should be changed in proportion, that is, the frequency of the inverter is controlled while changing the frequency, so that the magnetic flux of the motor is kept constant to avoid the occurrence of weak magnetic and magnetic saturation. This type of control is mostly used for energy-saving inverters such as fans and pumps.
5. When the motor is driven by the commercial frequency power supply, the current increases when the voltage drops. For the inverter drive, if the voltage drops when the frequency decreases, does the current increase?
When the frequency drops (low speed), if the same power is output, the current increases, but under a certain torque, the current hardly changes.
6. What is the starting current and starting torque of the motor when the inverter is running?
The inverter is operated, and the frequency and voltage are increased correspondingly with the acceleration of the motor. The starting current is limited to 150% of the rated current (125% to 200% depending on the model). When starting directly with the commercial frequency power supply, the starting current is 6 to 7 times, so mechanical and electrical impact will occur. It can be started smoothly with the inverter drive (starting time becomes longer). The starting current is 1.2~1.5 times of the rated current, and the starting torque is 70%~120% of rated torque. For the inverter with automatic torque boosting function, the starting torque is 100% or more, and it can start with full load.
7. What does V/f mode mean?
The voltage V also decreases proportionally as the frequency decreases. This problem has been explained in answer 4. The proportional relationship between V and f is predetermined in consideration of the characteristics of the motor. Usually, there are several characteristics in the memory device (ROM) of the controller, which can be selected by a switch or a dial.
8. How does the torque of the motor change when V and f are changed proportionally?
When the frequency is lowered to completely reduce the voltage proportionally, since the AC resistance becomes small and the DC resistance does not change, the torque generated at the low speed tends to decrease. Therefore, given V/f at low frequencies, the output voltage is increased somewhat in order to obtain a certain starting torque, which is called an enhanced starting. It can be implemented by various methods, such as automatic method, V/f mode selection or potentiometer adjustment.
9. In the manual, the shift range is 60~6Hz, which is 10:1. Is there no output power below 6Hz?
The power can still be output below 6 Hz, but according to the conditions of the motor temperature rise and the starting torque, the minimum frequency of use is about 6 Hz. This motor can output the rated torque without causing serious heating problems. The actual output frequency (starting frequency) of the inverter is 0.5~3Hz according to the model.
10. For the combination of general motors, the torque is required to be above 60 Hz. Is it ok?
Usually not allowed. Above 60Hz (also in the mode above 50Hz) the voltage is constant, generally constant power characteristics, when the same torque is required at high speed, we must pay attention to the choice of motor and inverter capacity
11. What does it mean to open a ring?
A speed detector (PG) is provided for the motor device to be used, and the actual speed is fed back to the control device for control, which is called "closed loop". If the PG is not operated, it is called "open loop". General-purpose inverters are mostly open-loop, and some models use PG feedback.
12. What should I do if the actual speed is different for a given speed?
When the ring is open, even if the inverter outputs a given frequency, the motor's speed will fluctuate within the range of rated slip (1%~5%) when the motor is running with load. For the requirement that the speed regulation accuracy is relatively high, even if the load is changed, it is required to operate at a speed close to a given speed, and an inverter (optional) having a PG feedback function can be used.
13. If the motor with PG is used, can the speed accuracy be improved after feedback?
The inverter with PG feedback function has improved accuracy. However, the speed accuracy depends on the accuracy of the PG itself and the resolution of the inverter output frequency.
14. What does the stall prevention function mean?
If the given acceleration time is too short, the output frequency of the inverter changes far more than the change of the speed (electrical angle frequency), the inverter will trip due to the overcurrent, and the operation stops. This is called stall. In order to prevent the stall from running, the magnitude of the current is detected for frequency control. When the acceleration current is too large, the acceleration rate is appropriately slowed down. The same is true when decelerating. The combination of the two is the stall function.
15. The heat dissipation of the inverter
1). If you want to use the inverter correctly, you must carefully consider the heat dissipation problem.
The failure rate of the inverter increases exponentially with increasing temperature, and the service life decreases exponentially with increasing temperature. When the ambient temperature rises by 10 degrees, the average life of the inverter is halved. When the inverter is working, the current flowing through the inverter is very large, and the heat generated by the inverter is also very large. The influence of the heat generation cannot be ignored. Generally, the inverter is installed in the control cabinet. We need to know what the heat output of a frequency converter is. It can be estimated by the following formula:
Approximate calorific value = inverter capacity (KW) × 55 [W]
Here, if the inverter capacity is based on the constant torque load (overcurrent capability 150% * 60s) If the inverter has a DC reactor or an AC reactor and is also inside the cabinet, the heat will be even more Bigger. It is better to install the reactor on the side of the inverter or above. At this time, you can use the estimation: Inverter capacity (KW) × 60 [W] Because the hardware of each inverter manufacturer is similar, the above formula can be used for each brand of products. Note: If there is a braking resistor, because the braking resistor has a large heat dissipation, it is best to install the position separately from the inverter, such as on or near the cabinet.
2.) How to reduce the heat generated in the control cabinet?
When the inverter is installed in the control cabinet, consider the problem of the heating value of the inverter. According to the increase in the amount of heat generated in the cabinet, the size of the cabinet should be appropriately increased. Therefore, in order to minimize the size of the control cabinet, it is necessary to reduce the amount of heat generated in the cabinet as much as possible. If the radiator part of the inverter is placed outside the control cabinet when the inverter is installed, 70% of the heat generated by the inverter will be released to the outside of the control cabinet. Since large-capacity inverters have a large amount of heat, they are more effective for large-capacity inverters. The spacer can also be used to separate the body from the heat sink, so that the heat dissipation of the heat sink does not affect the body of the inverter. This effect is also very good.
Note: The thermal design of the inverter is based on vertical installation, and the heat dissipation will be worse when it is placed horizontally!
3.) The inverters with a slightly larger power of the cooling fan are equipped with a cooling fan. At the same time, it is also recommended to install a cooling fan on the air outlet of the control cabinet. A filter screen is added to the air inlet to prevent dust from entering the control cabinet. Note that the fans on the control cabinet and the inverter are all required, and no one can replace who.
4.) Other questions about heat dissipation
1. At altitudes above 1000 m, because the air density is reduced, the cooling air volume of the cabinet should be increased to improve the cooling effect. In theory, the frequency converter should also consider derating, which is reduced by 5% per 1000m. However, in fact, because the load capacity and heat dissipation capacity of the designed inverter are generally larger than the actual use, it is also necessary to look at the specific application. For example, at 1500m, but periodic loads, such as elevators, do not need to be derated.
2. Switching frequency: The heat generated by the inverter is mainly from the IGBT. The heating of the IGBT is concentrated at the moment of opening and closing. Therefore, the natural heat of the inverter becomes larger when the switching frequency is high. Some manufacturers claim that reducing the switching frequency can be expanded, which is the reason.
16. Q&A on Leakage Current Q: What are the forms of leakage current? A: There are two types: motor cable to earth leakage current and cable Q: Why is there a leakage current problem? A: Leakage current is generally small when the inverter is not used. When the inverter is used, because the power module of the inverter is switched at a high speed, there is a higher harmonic in the output current. Because of the inductance between the cable and the cable, there is a large leakage current (up to 10 times that of the inverter). Q: Is there a relationship between leakage current and switching frequency? A: The smaller the switching frequency, the smaller the leakage current. Q: What is the relationship between leakage current and motor power? A: The higher the power, the larger the leakage current. Q: What is the relationship between leakage current and grounding? A: There is no direct relationship. However, poor grounding increases the likelihood of electric shock. Q: What are the countermeasures for leakage current? A: Reduce the switching frequency, which is the distance between the cables, the distance between the cable and the ground, and increase the leakage current setting level of the switch. Q: What is the regulation of the leakage current level of the inverter? A: Not yet.
17. At present, frequency conversion AC speed regulation has spread all over metallurgy, electric power, and other fields. The frequency converter is a device that realizes the speed control operation of the motor by utilizing the characteristic that the synchronous speed of the alternating current motor changes with the change of the motor voltage frequency. Among them, the setting of several parameters is very important, which will directly affect the reasonable use of the frequency converter.
Setting of several important parameters
1. Selection of V/f type The choice of V/f type includes the highest frequency, basic frequency and torque type.
The highest frequency is the highest frequency at which the drive-motor system can operate. Since the maximum frequency of the inverter itself may be high, when the maximum frequency allowed by the motor is lower than the highest frequency of the inverter, it should be set according to the requirements of the motor and its load. The basic frequency is the dividing line between the inverter for constant power control and constant torque control of the motor, and should be set according to the rated rated voltage of the motor. The torque type refers to whether the load is a constant torque load or a variable torque load. The user selects one of the types according to the V/f type map and the characteristics of the load in the instruction manual of the inverter. According to the actual situation and actual requirements of the motor, the maximum frequency is set to 83.4Hz, and the basic frequency is set to 50Hz. Load type: constant torque load below 50Hz, constant power load from 50~83.4Hz.
2. How to adjust the starting torque
The starting torque is adjusted to improve the low speed performance of the inverter when starting, so that the torque output by the motor can meet the requirements of production start. In the asynchronous motor variable frequency speed control system, the torque control is more complicated. In the low frequency band, the influence of resistance and leakage reactance cannot be ignored. If V/f is kept constant, the magnetic flux will decrease, which will reduce the output torque of the motor. For this reason, the voltage is appropriately compensated at the low frequency band to increase the torque. However, the influence of leakage impedance is not only related to frequency, but also related to the magnitude of motor current. Accurate compensation is very difficult. In recent years, some inverters that can compensate for themselves have been developed abroad, but the calculation amount is large, and the hardware and software are complicated. Therefore, the general inverters are manually set and compensated by the user. For the inverter we use, it is appropriate to set the torque boost to between 1% and 5%.
3. How to set the running equation of the motor for acceleration and deceleration time:
Where: Tt is the electromagnetic torque; T1 is the load torque motor acceleration dw/dt depends on the acceleration torque (Tt, T1), and the frequency change rate of the inverter during start and brake is set by the user. If the motor's moment of inertia J and the motor load change at a preset frequency change rate increase or decrease, there may be insufficient acceleration torque, which may cause the motor to stall, that is, the motor speed and the inverter output frequency are not coordinated, resulting in Current or over voltage. Therefore, it is necessary to set the acceleration and deceleration time according to the motor inertia and load, so that the frequency change rate of the inverter can be coordinated with the motor speed change rate. The way to check if this setting is reasonable is to select the acceleration and deceleration time settings according to experience. If overcurrent occurs during start-up, the acceleration time can be extended appropriately; if overcurrent occurs during braking, the deceleration time should be extended appropriately; on the other hand, the acceleration and deceleration time should not be set too long, and the time will be too long. Affects production efficiency, especially when frequently starting and braking. We set the acceleration time to 15s and the deceleration time to 5s.
4 . The frequency cross-jump V/f control inverter drives the asynchronous motor in certain frequency segments.
The current and speed of the motor will oscillate. In severe cases, the system will not operate. Even the overcurrent protection during the acceleration process will prevent the motor from starting normally. It is more serious when the motor is lightly loaded or the amount of rotation is small. Therefore, the variable frequency converter is equipped with a frequency jump function. The user can set the jump point and the jump point width on the V/f curve according to the frequency point at which the system appears to oscillate. These frequency segments can be automatically skipped when the motor accelerates to ensure normal system operation.
5 Overload Rate Setting This setting is used for inverter and motor overload protection.
When the output current of the inverter is greater than the setting value of the overload ratio and the OL setting value determined by the rated current of the motor, the inverter performs overload protection (OL) with the inverse time characteristic. When the overload protection is activated, the inverter stops outputting. 2.6 Input of motor parameters Some parameters of the inverter input items are the input of basic motor parameters, such as motor power, rated voltage, rated current, rated speed, and number of poles. The input of these parameters is very important and will directly affect the normal function of some protection functions in the inverter. It must be correctly input according to the actual parameters of the motor to ensure the normal use of the inverter.
four. Frequently encountered problems in the commissioning and use of the inverter1.) Among them, overvoltage is the most common phenomenon. After the overvoltage is generated, the inverter will prevent the internal circuit from being damaged, and its overvoltage protection function will operate, causing the inverter to stop running, resulting in the device not working properly. Therefore, measures must be taken to eliminate overvoltage and prevent malfunctions. Since the inverter and the motor are different in application, the cause of the overvoltage is different, so take corresponding countermeasures according to the specific situation.
2) Overvoltage generation and regenerative braking The overvoltage of the inverter refers to the inverter voltage exceeding the rated voltage due to various reasons, and is concentrated on the DC voltage of the DC bus of the inverter. During normal operation, the DC voltage of the inverter is the average value after three-phase full-wave rectification.
If calculated with a line voltage of 380V, the average DC voltage Ud=1.35U line = 513V. When an overvoltage occurs, the storage capacitor on the DC bus will be charged. When the voltage rises to about 700V, the inverter overvoltage protection action (depending on the model). There are two main causes of overvoltage: power supply overvoltage and regenerative overvoltage.
The overvoltage of the power supply means that the DC bus voltage exceeds the rated value because the power supply voltage is too high. Most inverters now have an input voltage of up to 460V, so the overvoltage caused by the power supply is extremely rare. The main issue discussed in this paper is the regenerative overvoltage. The main reason for generating regenerative overvoltage is as follows: When the large GD2 (flywheel torque) load decelerates, the deceleration time of the inverter is set too short; the motor is affected by external force (fan, drafting machine) or potential energy load (elevator, crane). For these reasons, the actual motor speed is higher than the command speed of the inverter, that is, the motor rotor speed exceeds the synchronous speed. At this time, the slip of the motor is negative, and the direction of the rotor winding cutting the rotating magnetic field is opposite to that of the motor state. The electromagnetic torque generated is a braking torque that hinders the direction of rotation. Therefore, the motor is actually in a power generation state, and the kinetic energy of the load is "regenerated" into electrical energy. The regenerative energy charges the inverter DC storage capacitor through the freewheeling diode of the inverter, so that the DC bus voltage rises, which is the regenerative overvoltage. Since the torque generated during the process of regenerating the overvoltage is opposite to the original torque, it is the braking torque, so the process of regenerating the overvoltage is the process of regenerative braking. In other words, the regenerative energy is eliminated and the braking torque is increased. If the regenerative energy is not large, the inverter and the motor itself have 20% regenerative braking capacity, and this part of the electric energy will be consumed by the inverter and the motor. If this part of the energy exceeds the consumption capacity of the inverter and the motor, the capacitance of the DC link will be overcharged, and the overvoltage protection function of the inverter will operate to stop the operation. In order to avoid this situation, this part of the energy must be disposed of in time, and the braking torque is also increased, which is the purpose of regenerative braking.
3) Preventive measures for overvoltage: Due to the different causes of overvoltage, the countermeasures adopted are different. For the overvoltage phenomenon generated during the parking process, if there is no special requirement for the parking time or position, it can be solved by extending the deceleration time of the inverter or free parking. The so-called free stop means that the inverter disconnects the main switching device and allows the motor to coast and stop. If there is a certain requirement for parking time or parking position, DC braking (DC braking) function can be used. The DC braking function is to decelerate the motor to a certain frequency and then input DC power into the stator winding of the motor to form a static magnetic field. The rotor winding of the motor cuts this magnetic field to generate a braking torque, so that the kinetic energy of the load is converted into electrical energy and is consumed in the form of heat in the rotor circuit of the motor. Therefore, this braking is also called energy braking. In the process of DC braking, two processes of regenerative braking and energy braking are actually included. This braking method is only 30-60% efficient for regenerative braking and has a low braking torque. Since the motor is overheated by consuming energy in the motor, the braking time should not be too long. Moreover, the DC braking start frequency, braking time and braking voltage are all manually set and cannot be automatically adjusted according to the level of the regenerative voltage. Therefore, DC braking cannot be used for overvoltage generated during normal operation, and can only be used for Braking when parking. For deceleration (from high speed to low speed, but not stopping), the overvoltage generated by the excessive GD2 (flywheel torque) of the load can be solved by appropriately extending the deceleration time. In fact, this method also uses the principle of regenerative braking. The deceleration time is only to control the charging speed of the load to the inverter, so that the 20% regenerative braking capability of the inverter itself can be rationally utilized. As for the load that causes the motor to regenerate due to the action of external force (including the potential discharge), since it is normally in the braking state, the regenerative energy is too high to be consumed by the inverter itself, so it is impossible to use DC braking or The method of extending the deceleration time. Compared with DC braking, regenerative braking has higher braking torque, and the braking torque can be related to the braking torque required by the load (ie, the level of regenerative energy). Automatic control. Regenerative braking is therefore best suited to provide braking torque to the load during normal operation.
4) Regeneration braking method:
1. Energy consumption type: This method is to connect a braking resistor in parallel with the DC link of the inverter to control the on/off of a power tube by detecting the DC bus voltage. When the DC bus voltage rises to about 700V, the power tube is turned on, and the regenerative energy is supplied to the resistor to be consumed as heat energy, thereby preventing the DC voltage from rising. Since the regenerative energy is not utilized, it is energy-consuming. The same energy consumption type, it differs from DC braking in that it consumes energy on the braking resistor outside the motor, and the motor does not overheat, so it can work more frequently.
2.并è”ç›´æµæ¯çº¿å¸æ”¶åž‹ï¼šé€‚ç”¨äºŽå¤šç”µæœºä¼ åŠ¨ç³»ç»Ÿï¼ˆå¦‚ç‰µä¼¸æœºï¼‰ï¼Œåœ¨è¿™ä¸ªç³»ç»Ÿä¸ï¼Œæ¯å°ç”µæœºå‡éœ€ä¸€å°å˜é¢‘器，多å°å˜é¢‘器共用一个网侧å˜æµå™¨ï¼Œæ‰€æœ‰çš„逆å˜éƒ¨å¹¶æŽ¥åœ¨ä¸€æ¡å…±ç”¨ç›´æµæ¯çº¿ä¸Šã€‚è¿™ç§ç³»ç»Ÿä¸å¾€å¾€æœ‰ä¸€å°æˆ–æ•°å°ç”µæœºæ£å¸¸å·¥ä½œäºŽåˆ¶åŠ¨çŠ¶æ€ï¼Œå¤„于制动状æ€çš„电机被其它电动机拖动，产生å†ç”Ÿèƒ½é‡ï¼Œè¿™äº›èƒ½é‡å†é€šè¿‡å¹¶è”ç›´æµæ¯çº¿è¢«å¤„于电动状æ€çš„电机所å¸æ”¶ã€‚在ä¸èƒ½å®Œå…¨å¸æ”¶çš„情况下，则通过共用的制动电阻消耗掉。这里的å†ç”Ÿèƒ½é‡éƒ¨åˆ†è¢«å¸æ”¶åˆ©ç”¨ï¼Œä½†æ²¡æœ‰å›žé¦ˆåˆ°ç”µç½‘ä¸ã€‚
3． 能é‡å›žé¦ˆåž‹ï¼šèƒ½é‡å›žé¦ˆåž‹çš„å˜é¢‘器网侧å˜æµå™¨æ˜¯å¯é€†çš„，当有å†ç”Ÿèƒ½é‡äº§ç”Ÿæ—¶ï¼Œå¯é€†å˜æµå™¨å°†å†ç”Ÿèƒ½é‡å›žé¦ˆç»™ç”µç½‘，使å†ç”Ÿèƒ½é‡å¾—到完全利用。但这ç§æ–¹æ³•å¯¹ç”µæºçš„稳定性è¦æ±‚较高，一旦çªç„¶åœç”µï¼Œå°†å‘生逆å˜é¢ 覆。
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1.工作环境问题在å˜é¢‘器实际应用ä¸ï¼Œç”±äºŽå›½å†…客户除少数有专用机房外，大多为了é™ä½Žæˆæœ¬ï¼Œå°†å˜é¢‘器直接安装于工业现场。工作现场一般是ç°å°˜å¤§ã€æ¸©åº¦é«˜ï¼Œåœ¨å—方还有湿度大的问题。对于线缆行业还有金属粉尘，在陶瓷ã€å°æŸ“ç‰è¡Œä¸šè¿˜æœ‰è…蚀性气体和粉尘，在煤矿ç‰åœºåˆï¼Œè¿˜æœ‰é˜²çˆ†çš„è¦æ±‚ç‰ç‰ã€‚å› æ¤å¿…é¡»æ ¹æ®çŽ°åœºæƒ…况åšå‡ºç›¸åº”的对ç–。
2 å˜é¢‘器的安装设计基本è¦æ±‚
（1） å˜é¢‘器应该安装在控制柜内部。（2） å˜é¢‘器最好安装在控制柜内的ä¸éƒ¨;å˜é¢‘器è¦åž‚直安装，æ£ä¸Šæ–¹å’Œæ£ä¸‹æ–¹è¦é¿å…安装å¯èƒ½é˜»æŒ¡æŽ’风ã€è¿›é£Žçš„大元件。（3） å˜é¢‘器上ã€ä¸‹éƒ¨è¾¹ç¼˜è·ç¦»æŽ§åˆ¶æŸœé¡¶éƒ¨ã€åº•éƒ¨ã€æˆ–者隔æ¿ã€æˆ–者必须安装的大元件ç‰çš„最å°é—´è·ï¼Œåº”该大于300mm。柜内安装å˜é¢‘器的基本è¦æ±‚（4） 如果特殊用户在使用ä¸éœ€è¦å–掉键盘，则å˜é¢‘器é¢æ¿çš„键盘å”，一定è¦ç”¨èƒ¶å¸¦ä¸¥æ ¼å¯†å°æˆ–者采用å‡é¢æ¿æ›¿æ¢ï¼Œé˜²æ¢ç²‰å°˜å¤§é‡è¿›å…¥å˜é¢‘器内部。（5） 对å˜é¢‘器è¦è¿›è¡Œå®šæœŸç»´æŠ¤ï¼ŒåŠæ—¶æ¸…ç†å†…部的粉尘ç‰ã€‚（6） 其它的基本安装ã€ä½¿ç”¨è¦æ±‚å¿…é¡»éµå®ˆç”¨æˆ·æ‰‹å†Œä¸Šçš„有关说明;如有疑问请åŠæ—¶è”系相应厂家技术支æŒäººå‘˜ã€‚
3. 防尘控制柜的设计è¦æ±‚
在多粉尘场所，特别是多金属粉尘ã€çµ®çŠ¶ç‰©çš„场所使用å˜é¢‘器时，采å–æ£ç¡®ã€åˆç†çš„防护措施是å分必è¦çš„，防尘措施得当对ä¿è¯å˜é¢‘器æ£å¸¸å·¥ä½œéžå¸¸é‡è¦ã€‚总体è¦æ±‚控制柜整体应该密å°ï¼Œåº”该通过专门设计的进风å£ã€å‡ºé£Žå£è¿›è¡Œé€šé£Ž;控制柜顶部应该有防护网和防护顶盖出风å£;控制柜底部应该有底æ¿å’Œè¿›é£Žå£ã€è¿›çº¿å”，并且安装防尘网。
（1） 控制柜的风é“è¦è®¾è®¡åˆç†ï¼ŒæŽ’风通畅，é¿å…在柜内形æˆæ¶¡æµï¼Œåœ¨å›ºå®šçš„ä½ç½®å½¢æˆç°å°˜å †ç§¯ã€‚
（2） 控制柜顶部出风å£ä¸Šé¢è¦å®‰è£…防护顶盖，防æ¢æ‚物直接è½å…¥ï¼›é˜²æŠ¤é¡¶ç›–高度è¦åˆç†ï¼Œä¸å½±å“排风。防护顶盖的侧é¢å‡ºé£Žå£è¦å®‰è£…防护网，防æ¢çµ®çŠ¶æ‚物直接è½å…¥ã€‚
（3） 如果采用控制柜顶部侧é¢æŽ’风方å¼ï¼Œå‡ºé£Žå£å¿…须安装防护网。
（4） 一定è¦ç¡®ä¿æŽ§åˆ¶æŸœé¡¶éƒ¨çš„è½´æµé£Žæœºæ—‹è½¬æ–¹å‘æ£ç¡®ï¼Œå‘外抽风。如果风机安装在控制柜顶部的外部，必须确ä¿é˜²æŠ¤é¡¶ç›–与风机之间有足够的高度；如果风机安装在控制柜顶部的内部，安装所需螺钉必须采用æ¢é€†å¼¹ä»¶ï¼Œé˜²æ¢é£Žæœºè„±è½é€ æˆæŸœå†…元件和设备的æŸåã€‚å»ºè®®åœ¨é£Žæœºå’ŒæŸœä½“ä¹‹é—´åŠ è£…å¡‘æ–™æˆ–è€…æ©¡èƒ¶å‡æŒ¯åž«åœˆï¼Œå¯ä»¥å¤§å¤§å‡å°é£Žæœºéœ‡åŠ¨é€ æˆçš„噪音。
（5） 控制柜的å‰ã€åŽé—¨å’Œå…¶ä»–接ç¼å¤„，è¦é‡‡ç”¨å¯†å°åž«ç‰‡æˆ–者密å°èƒ¶è¿›è¡Œä¸€å®šçš„密å°å¤„ç†ï¼Œé˜²æ¢ç²‰å°˜è¿›å…¥ã€‚
（6） 控制柜底部ã€ä¾§æ¿çš„所有进风å£ã€è¿›çº¿å”，一定è¦å®‰è£…防尘网。阻隔絮状æ‚物进入。防尘网应该设计为å¯æ‹†å¸å¼ï¼Œä»¥æ–¹ä¾¿æ¸…ç†ã€ç»´æŠ¤ã€‚é˜²å°˜ç½‘çš„ç½‘æ ¼è¦å°ï¼Œèƒ½å¤Ÿæœ‰æ•ˆé˜»æŒ¡ç»†å°çµ®çŠ¶ç‰©ï¼ˆä¸Žä¸€èˆ¬å®¶ç”¨é˜²èšŠè‡çº±çª—çš„ç½‘æ ¼ç›¸ä»¿ï¼‰;æˆ–è€…æ ¹æ®å…·ä½“情况确定åˆé€‚çš„ç½‘æ ¼å°ºå¯¸ã€‚é˜²å°˜ç½‘å››å‘¨ä¸ŽæŽ§åˆ¶æŸœçš„ç»“åˆå¤„è¦å¤„ç†ä¸¥å¯†ã€‚
（7） 对控制柜一定è¦è¿›è¡Œå®šæœŸç»´æŠ¤ï¼ŒåŠæ—¶æ¸…ç†å†…部ã€å¤–部的粉尘ã€çµ®æ¯›ç‰æ‚物。维护周期å¯æ ¹æ®å…·ä½“情况而定，但应该å°äºŽ2～3个月;对于粉尘严é‡çš„场所，建议维护周期在1个月左å³ã€‚防尘控制柜的安装è¦æ±‚4.防潮湿霉å˜çš„控制柜的设计è¦æ±‚多数å˜é¢‘器厂家内部的å°åˆ¶æ¿ã€é‡‘属结构件å‡æœªè¿›è¡Œé˜²æ½®æ¹¿éœ‰å˜çš„特殊处ç†ï¼Œå¦‚æžœå˜é¢‘器长期处于这ç§çŠ¶æ€ï¼Œé‡‘属结构件容易产生锈蚀，对于导电铜排在高温è¿è¡Œæƒ…å†µä¸‹ï¼Œæ›´åŠ å‰§äº†é”ˆèš€çš„è¿‡ç¨‹ã€‚å¯¹äºŽå¾®æœºæŽ§åˆ¶æ¿å’Œé©±åŠ¨ç”µæºæ¿ä¸Šçš„细å°é“œè´¨å¯¼çº¿ï¼Œç”±äºŽé”ˆèš€å°†é€ æˆæŸåï¼Œå› æ¤ï¼Œå¯¹äºŽåº”用于潮湿和和å«æœ‰è…蚀性气体的场åˆï¼Œå¿…须对于使用å˜é¢‘器的内部设计有基本è¦æ±‚，例如å°åˆ·ç”µè·¯æ¿å¿…须采用三防漆喷涂处ç†ï¼Œå¯¹äºŽç»“构件必须采用镀é•é“¬ç‰å¤„ç†å·¥è‰ºã€‚
4.除æ¤ä¹‹å¤–，还需è¦é‡‡å–其它积æžã€æœ‰æ•ˆã€åˆç†çš„防潮湿ã€é˜²è…蚀气体的措施。（1） 控制柜å¯ä»¥å®‰è£…在å•ç‹¬çš„ã€å¯†é—的采用空调的机房，æ¤æ–¹æ³•é€‚用控制设备较多，建立机房的æˆæœ¬ä½ŽäºŽæŸœä½“å•ç‹¬å¯†é—处ç†çš„场åˆï¼Œæ¤æ—¶æŽ§åˆ¶æŸœå¯ä»¥é‡‡ç”¨å¦‚上防尘或者一般环境设计å³å¯ã€‚（2） 采用独立进风å£ã€‚å•ç‹¬çš„进风å£å¯ä»¥è®¾åœ¨æŽ§åˆ¶æŸœçš„底部，通过独立密é—地沟与外部干净环境连接，æ¤æ–¹æ³•éœ€è¦åœ¨è¿›é£Žå£å¤„安装一个防尘网，如果地沟超过5m以上时，å¯ä»¥è€ƒè™‘åŠ è£…é¼“é£Žæœºã€‚ï¼ˆ3） 密é—控制柜内å¯ä»¥åŠ 装å¸æ¹¿çš„干燥剂或者å¸é™„毒性气体的活性æ料，并近期更æ¢ã€‚
5. 干扰问题5.1 å˜é¢‘器对微机控制æ¿çš„干扰在注塑机ã€ç”µæ¢¯ç‰çš„控制系统ä¸ï¼Œå¤šé‡‡ç”¨å¾®æœºæˆ–者PLCè¿›è¡ŒæŽ§åˆ¶ï¼Œåœ¨ç³»ç»Ÿè®¾è®¡æˆ–è€…æ”¹é€ è¿‡ç¨‹ä¸ï¼Œä¸€å®šè¦æ³¨æ„å˜é¢‘器对微机控制æ¿çš„干扰问题。由于用户自己设计的微机控制æ¿ä¸€èˆ¬å·¥è‰ºæ°´å¹³å·®ï¼Œä¸ç¬¦åˆEMCå›½é™…æ ‡å‡†ï¼Œåœ¨é‡‡ç”¨å˜é¢‘器åŽï¼Œäº§ç”Ÿçš„ä¼ å¯¼å’Œè¾å°„å¹²æ‰°ï¼Œå¾€å¾€å¯¼è‡´æŽ§åˆ¶ç³»ç»Ÿå·¥ä½œå¼‚å¸¸ï¼Œå› æ¤éœ€è¦é‡‡å–å¿…è¦æŽªæ–½ã€‚
（1） 良好的接地。电机ç‰å¼ºç”µæŽ§åˆ¶ç³»ç»Ÿçš„接地线必须通过接地汇æµæŽ’å¯é 接地，微机控制æ¿çš„å±è”½åœ°ï¼Œæœ€å¥½å•ç‹¬æŽ¥åœ°ã€‚对于æŸäº›å¹²æ‰°ä¸¥é‡çš„场åˆï¼Œå»ºè®®å°†ä¼ 感器ã€I/O接å£å±è”½å±‚与控制æ¿çš„控制地相连ã€3】。
（2） 给微机控制æ¿è¾“入电æºåŠ 装EMI滤波器ã€å…±æ¨¡ç”µæ„Ÿã€é«˜é¢‘ç£çŽ¯ç‰ï¼Œæˆæœ¬ä½Žã€‚å¯ä»¥æœ‰æ•ˆæŠ‘åˆ¶ä¼ å¯¼å¹²æ‰°ã€‚å¦å¤–在è¾å°„干扰严é‡çš„场åˆï¼Œå¦‚周围å˜åœ¨GSMã€æˆ–者å°çµé€šæœºç«™æ—¶ï¼Œå¯ä»¥å¯¹å¾®æœºæŽ§åˆ¶æ¿æ·»åŠ 金属网状å±è”½ç½©è¿›è¡Œå±è”½å¤„ç†ã€‚微机控制æ¿çš„电æºæŠ—干扰措施
（3） ç»™å˜é¢‘å™¨è¾“å…¥åŠ è£…EMI滤波器，å¯ä»¥æœ‰æ•ˆæŠ‘制å˜é¢‘å™¨å¯¹ç”µç½‘çš„ä¼ å¯¼å¹²æ‰°ï¼ŒåŠ è£…è¾“å…¥äº¤æµå’Œç›´æµç”µæŠ—器L1ã€L2，å¯ä»¥æé«˜åŠŸçŽ‡å› æ•°ï¼Œå‡å°è°æ³¢æ±¡æŸ“，综åˆæ•ˆæžœå¥½ã€‚在æŸäº›ç”µæœºä¸Žå˜é¢‘器之间è·ç¦»è¶…过100m的场åˆï¼Œéœ€è¦åœ¨å˜é¢‘å™¨ä¾§æ·»åŠ äº¤æµè¾“出电抗器L3ï¼Œè§£å†³å› ä¸ºè¾“å‡ºå¯¼çº¿å¯¹åœ°åˆ†å¸ƒå‚æ•°é€ æˆçš„æ¼ç”µæµä¿æŠ¤å’Œå‡å°‘对外部的è¾å°„干扰。一个行之有效的方法就是采用钢管穿线或者å±è”½ç”µç¼†çš„方法，并将钢管外壳或者电缆å±è”½å±‚与大地å¯é 连接。请注æ„，在ä¸æ·»åŠ 交æµè¾“出电抗器L3时，如果采用钢管穿线或者å±è”½ç”µç¼†çš„方法，增大了输出对地的分布电容，容易出现过æµã€‚当然在实际ä¸ä¸€èˆ¬åªé‡‡å–å…¶ä¸çš„一ç§æˆ–è€…å‡ ç§æ–¹æ³•ã€‚
（4） å‡å°å˜é¢‘å™¨å¯¹å¤–éƒ¨æŽ§åˆ¶è®¾å¤‡çš„å¹²æ‰°æŽªæ–½å¯¹æ¨¡æ‹Ÿä¼ æ„Ÿå™¨æ£€æµ‹è¾“å…¥å’Œæ¨¡æ‹ŸæŽ§åˆ¶ä¿¡å·è¿›è¡Œç”µæ°”å±è”½å’Œéš”离。在å˜é¢‘器组æˆçš„控制系统设计过程ä¸ï¼Œå»ºè®®å°½é‡ä¸è¦é‡‡ç”¨æ¨¡æ‹ŸæŽ§åˆ¶ï¼Œç‰¹åˆ«æ˜¯æŽ§åˆ¶è·ç¦»å¤§äºŽ1Mï¼Œè·¨æŽ§åˆ¶æŸœå®‰è£…çš„æƒ…å†µä¸‹ã€‚å› ä¸ºå˜é¢‘器一般都有多段速设定ã€å¼€å…³é¢‘率é‡è¾“入输出，å¯ä»¥æ»¡è¶³è¦æ±‚。如果éžè¦ç”¨æ¨¡æ‹Ÿé‡æŽ§åˆ¶æ—¶ï¼Œå»ºè®®ä¸€å®šé‡‡ç”¨å±è”½ç”µç¼†ï¼Œå¹¶åœ¨ä¼ 感器侧或者å˜é¢‘器侧实现远端一点接地。如果干扰ä»æ—§ä¸¥é‡ï¼Œéœ€è¦å®žçŽ°DC/DC隔离措施。å¯ä»¥é‡‡ç”¨æ ‡å‡†çš„DC/DC模å—，或者采用V/F转æ¢ï¼Œå…‰è—•éš”离å†é‡‡ç”¨é¢‘率设定输入的方法。
5.2 å˜é¢‘器本身抗干扰问题
当å˜é¢‘器的供电系统附近，å˜åœ¨é«˜é¢‘冲击负载如电焊机ã€ç”µé•€ç”µæºã€ç”µè§£ç”µæºæˆ–者采用滑环供电的场åˆï¼Œå˜é¢‘å™¨æœ¬èº«å®¹æ˜“å› ä¸ºå¹²æ‰°è€Œå‡ºçŽ°ä¿æŠ¤ã€‚应采用如下措施：
（1） 在å˜é¢‘å™¨è¾“å…¥ä¾§æ·»åŠ ç”µæ„Ÿå’Œç”µå®¹ï¼Œæž„æˆLC滤波网络。
（2） å˜é¢‘器的电æºçº¿ç›´æŽ¥ä»Žå˜åŽ‹å™¨ä¾§ä¾›ç”µã€‚
（3） 在æ¡ä»¶è®¸å¯çš„情况下，å¯ä»¥é‡‡ç”¨å•ç‹¬çš„å˜åŽ‹å™¨ã€‚
（4） 在采用外部开关é‡æŽ§åˆ¶ç«¯å控制时，连接线路较长时，建议采用å±è”½ç”µç¼†ã€‚当控制线路与主回路电æºå‡åœ¨åœ°æ²Ÿä¸åŸ‹è®¾æ—¶ï¼Œé™¤æŽ§åˆ¶çº¿å¿…须采用å±è”½ç”µç¼†å¤–，主电路线路必须采用钢管å±è”½ç©¿çº¿ï¼Œå‡å°å½¼æ¤å¹²æ‰°ï¼Œé˜²æ¢å˜é¢‘器的误动作。
（5） 在采用外部模拟é‡æŽ§åˆ¶ç«¯å控制时，如果连接线路在1M以内，采用å±è”½ç”µç¼†è¿žæŽ¥ï¼Œå¹¶å®žæ–½å˜é¢‘器侧一点接地å³å¯;如果线路较长，现场干扰严é‡çš„场åˆï¼Œå»ºè®®åœ¨å˜é¢‘å™¨ä¾§åŠ è£…DC/DC隔离模å—或者采用ç»è¿‡V/F转æ¢ï¼Œé‡‡ç”¨é¢‘率指令给定模å¼è¿›è¡ŒæŽ§åˆ¶ã€‚
（6） 在采用外部通信控制端å控制时，建议采用å±è”½åŒç»žçº¿ï¼Œå¹¶å°†å˜é¢‘器侧的å±è”½å±‚接地（PE），如果干扰éžå¸¸ä¸¥é‡ï¼Œå»ºè®®å°†å±è”½å±‚接控制电æºåœ°ï¼ˆGND）。对于RS232通信方å¼ï¼Œæ³¨æ„控制线路尽é‡ä¸è¦è¶…过15m，如果è¦åŠ 长，必须éšä¹‹é™ä½Žé€šä¿¡æ³¢ç‰¹çŽ‡ï¼Œåœ¨100må·¦å³æ—¶ï¼Œèƒ½å¤Ÿæ£å¸¸é€šä¿¡çš„波特率å°äºŽ600bps。对于RS485通信，还必须考虑终端匹é…电阻ç‰ã€‚对于采用现场总线的高速控制系统，通信电缆必须采用专用电缆，并采用多点接地的方å¼ï¼Œæ‰èƒ½å¤Ÿæ高å¯é 性。
6. 电网质é‡é—®é¢˜
在高频冲击负载如电焊机ã€ç”µé•€ç”µæºã€ç”µè§£ç”µæºç‰åœºåˆï¼Œç”µåŽ‹ç»å¸¸å‡ºçŽ°é—ªå˜;在一个车间ä¸ï¼Œæœ‰å‡ 百å°å˜é¢‘器ç‰å®¹æ€§æ•´æµè´Ÿè½½åœ¨å·¥ä½œæ—¶ï¼Œç”µç½‘çš„è°æ³¢éžå¸¸å¤§ï¼Œå¯¹äºŽç”µç½‘è´¨é‡æœ‰å¾ˆä¸¥é‡çš„æ±¡æŸ“ï¼Œå¯¹è®¾å¤‡æœ¬èº«ä¹Ÿæœ‰ç›¸å½“çš„ç ´å作用，轻则ä¸èƒ½å¤Ÿè¿žç»æ£å¸¸è¿è¡Œï¼Œé‡åˆ™é€ æˆè®¾å¤‡è¾“入回路的æŸå。å¯ä»¥é‡‡å–以下的措施：集ä¸æ•´æµçš„ç›´æµå…±æ¯çº¿ä¾›ç”µæ–¹å¼
（1） 在高频冲击负载如电焊机ã€ç”µé•€ç”µæºã€ç”µè§£ç”µæºç‰åœºåˆå»ºè®®ç”¨æˆ·å¢žåŠ æ— åŠŸé™è¡¥è£…置，æé«˜ç”µç½‘åŠŸçŽ‡å› æ•°å’Œè´¨é‡ã€‚
（2） 在å˜é¢‘器比较集ä¸çš„车间，建议采用集ä¸æ•´æµï¼Œç›´æµå…±æ¯çº¿ä¾›ç”µæ–¹å¼ã€‚建议用户采用12脉冲整æµæ¨¡å¼ã€‚优点是，è°æ³¢å°ã€èŠ‚能，特别适用于频ç¹èµ·åˆ¶åŠ¨ã€ç”µåŠ¨è¿è¡Œä¸Žå‘电è¿è¡ŒåŒæ—¶è¿›è¡Œçš„场åˆã€‚
（3） å˜é¢‘å™¨è¾“å…¥ä¾§åŠ è£…æ— æºLC滤波器，å‡å°è¾“å…¥è°æ³¢ï¼Œæé«˜åŠŸçŽ‡å› æ•°ï¼Œæˆæœ¬è¾ƒä½Žï¼Œå¯é 性高，效果好。
（4） å˜é¢‘å™¨è¾“å…¥ä¾§åŠ è£…æœ‰æºPFC装置，效果最好，但æˆæœ¬è¾ƒé«˜ã€‚
7. 电机的æ¼ç”µã€è½´ç”µåŽ‹ä¸Žè½´æ‰¿ç”µæµé—®é¢˜
å˜é¢‘器驱动感应电机的电机模型，Csf为定å与机壳之间的ç‰æ•ˆç”µå®¹ï¼ŒCsr为定å与转å之间的ç‰æ•ˆç”µå®¹ï¼ŒCrf为转å与机壳之间的ç‰æ•ˆç”µå®¹ï¼ŒRb为轴承对轴的电阻;Cbå’ŒZb为轴承油膜的电容和éžçº¿æ€§é˜»æŠ—。高频PWM脉冲输入下，电机内分布电容的电压耦åˆä½œç”¨æž„æˆç³»ç»Ÿå…±æ¨¡å›žè·¯ï¼Œä»Žè€Œå¼•èµ·å¯¹åœ°æ¼ç”µæµã€è½´ç”µåŽ‹ä¸Žè½´æ‰¿ç”µæµé—®é¢˜ã€‚å˜é¢‘器驱动感应电机的电机模型æ¼ç”µæµä¸»è¦æ˜¯PWM三相供电电压æžå…¶çž¬æ—¶ä¸å¹³è¡¡ç”µåŽ‹ä¸Žå¤§åœ°ä¹‹é—´é€šè¿‡Csf产生。其大å°ä¸ŽPWMçš„dv/dt大å°ä¸Žå¼€å…³é¢‘率大å°æœ‰å…³ï¼Œå…¶ç›´æŽ¥ç»“果将导致带有æ¼ç”µä¿æŠ¤è£…置动作。å¦å¤–，对于旧å¼ç”µæœºï¼Œç”±äºŽå…¶ç»ç¼˜æ料差，åˆç»è¿‡é•¿æœŸè¿è¡Œè€åŒ–，有些在ç»è¿‡å˜é¢‘æ”¹é€ åŽé€ æˆç»ç¼˜æŸåã€‚å› æ¤ï¼Œå»ºè®®åœ¨æ”¹é€ å‰ï¼Œå¿…须进行ç»ç¼˜çš„测试。对于新的å˜é¢‘电机的ç»ç¼˜ï¼Œè¦æ±‚è¦æ¯”æ ‡å‡†ç”µæœºé«˜å‡ºä¸€ä¸ªç‰çº§ã€‚轴承电æµä¸»è¦ä»¥ä¸‰ç§æ–¹å¼å˜åœ¨ï¼šdv/dt电æµã€EDM（Electric Discharge Machining）电æµå’ŒçŽ¯è·¯ç”µæµã€‚轴电压的大å°ä¸ä»…与电机内å„部分耦åˆç”µå®¹å‚数有关，且与脉冲电压上å‡æ—¶é—´å’Œå¹…值有关。dv/dt电æµä¸»è¦ä¸ŽPWM的上å‡æ—¶é—´tr有关，tr越å°ï¼Œdv/dt电æµçš„幅值越大;逆å˜å™¨è½½æ³¢é¢‘率越高，轴承电æµä¸çš„dv/dt电æµæˆåˆ†è¶Šå¤šã€‚EDM电æµå‡ºçŽ°å˜åœ¨ä¸€å®šçš„å¶ç„¶æ€§ï¼Œåªæœ‰å½“轴承润滑油层被击穿或者轴承内部å‘生接触时，å˜å‚¨åœ¨ç”µå转å对地电容Crf上的电è·ï¼ˆ1/2 Crf×Urf）通过轴承ç‰æ•ˆå›žè·¯Rbã€Cbå’ŒZb对地进行ç«èŠ±å¼æ”¾ç”µï¼Œé€ æˆè½´æ‰¿å…‰æ´åº¦ä¸‹é™ï¼Œé™ä½Žä½¿ç”¨å¯¿å‘½ï¼Œä¸¥é‡åœ°é€ æˆç›´æŽ¥æŸå。æŸå程度主è¦å–决于轴电压和å˜å‚¨åœ¨ç”µå转å对地电容Crf的大å°ã€‚环路电æµå‘生在电网å˜åŽ‹å™¨åœ°çº¿ã€å˜é¢‘器地线ã€ç”µæœºåœ°çº¿åŠç”µæœºè´Ÿè½½ä¸Žå¤§åœ°åœ°çº¿ä¹‹é—´çš„回路（如水泵类负载）ä¸ã€‚环路电æµä¸»è¦é€ æˆä¼ 导干扰和地线干扰，对å˜é¢‘器和电机影å“ä¸å¤§ã€‚é¿å…或者å‡å°çŽ¯æµçš„方法就是尽å¯èƒ½å‡å°åœ°çº¿å›žè·¯çš„阻抗。由于å˜é¢‘器接地线（PEå˜é¢‘器）一般与电机接地线（PE电机1ï¼‰è¿žæŽ¥åœ¨ä¸€ä¸ªç‚¹ï¼Œå› æ¤ï¼Œå¿…须尽å¯èƒ½åŠ 粗电机接地电缆线径，å‡å°ä¸¤è€…之间的电阻，åŒæ—¶å˜é¢‘器与电æºä¹‹é—´çš„地线采用地线铜æ¯æŽ’或者专用接地电缆，ä¿è¯è‰¯å¥½æŽ¥åœ°ã€‚å¯¹äºŽæ½œæ°´æ·±äº•æ³µè¿™æ ·çš„è´Ÿè½½ï¼ŒæŽ¥åœ°é˜»æŠ—ZE电机2å¯èƒ½å°äºŽZEå˜åŽ‹å™¨ä¸ŽZEå˜é¢‘器之和，容易形æˆåœ°çŽ¯æµï¼Œå»ºè®®æ–å¼€ZEå˜é¢‘器，抗干扰效果好。在å˜é¢‘器输出端串由电感ã€RC组æˆçš„æ£å¼¦æ³¢æ»¤æ³¢å™¨æ˜¯æŠ‘制轴电压与轴承电æµçš„有效途径。目å‰æœ‰å¤šå®¶åŽ‚家å¯æä¾›æ ‡å‡†æ»¤æ³¢å™¨ã€‚
å…。å˜é¢‘器功能å‚æ•°There are many function parameters of the inverter, generally there are dozens or even hundreds of parameters for the user to choose. In practical applications, it is not necessary to set and debug each parameter, and most of them only need to adopt the factory setting value.但有些å‚数由于和实际使用情况有很大关系，且有的还相互关è”ï¼Œå› æ¤è¦æ ¹æ®å®žé™…进行设定和调试。 Because the functions of each type of inverter are different, and the names of the same function parameters are also inconsistent, for the convenience of description, this article takes the basic parameter name of Fuji inverter as an example. Since the basic parameters are almost all types of frequency converters, it is completely possible to bypass the class.
ä¸€åŠ å‡é€Ÿæ—¶é—´åŠ 速时间就是输出频率从0上å‡åˆ°æœ€å¤§é¢‘率所需时间，å‡é€Ÿæ—¶é—´æ˜¯æŒ‡ä»Žæœ€å¤§é¢‘率下é™åˆ°0所需时间。 The acceleration and deceleration time is usually determined by the frequency setting signal rising and falling. When the motor is accelerating, the rate of increase of the frequency setting must be limited to prevent overcurrent, and when decelerating, the rate of decrease is limited to prevent overvoltage. Acceleration time setting requirement: Limit the acceleration current below the overcurrent capacity of the inverter, and do not cause the inverter to trip due to the over-speed. The deceleration time setting point is: prevent the smoothing circuit voltage from being too large, and do not make the regenerative overvoltage stall. Let the frequency converter trip. Acceleration and deceleration time can be calculated according to the load, but in the debugging, it is often set to set the long acceleration/deceleration time according to the load and experience. Observe the overcurrent and overvoltage alarm by starting and stopping the motor; then gradually set the acceleration/deceleration time. Shorten, the principle of no alarm occurs during operation, and repeat the operation several times to determine the optimal acceleration and deceleration time.
二转矩æå‡åˆå«è½¬çŸ©è¡¥å¿ï¼Œæ˜¯ä¸ºè¡¥å¿å› 电动机定å绕组电阻所引起的低速时转矩é™ä½Žï¼Œè€ŒæŠŠä½Žé¢‘率范围f/V增大的方法。设定为自动时，å¯ä½¿åŠ 速时的电压自动æå‡ä»¥è¡¥å¿èµ·åŠ¨è½¬çŸ©ï¼Œä½¿ç”µåŠ¨æœºåŠ 速顺利进行。 If manual compensation is used, a better curve can be selected by experiment depending on the load characteristics, especially the starting characteristics of the load. For variable torque loads, if the selection is improper, the output voltage will be too high at low speed, and the phenomenon of wasting electric energy may even occur when the motor is loaded with load and the current is large, and the speed is not going up.
三电åçƒè¿‡è½½ä¿æŠ¤
This function is set to protect the motor from overheating. It is the CPU inside the inverter calculates the temperature rise of the motor according to the running current value and frequency, thus performing overheat protection. This function is only applicable to the “one-for-one†occasion, and in the case of “one-to-oneâ€, a thermal relay should be added to each motor.电åçƒä¿æŠ¤è®¾å®šå€¼ï¼ˆ%）=ã€ç”µåŠ¨æœºé¢å®šç”µæµï¼ˆA）/å˜é¢‘器é¢å®šè¾“出电æµï¼ˆA）】×100%。
四频率é™åˆ¶å³å˜é¢‘器输出频率的上ã€ä¸‹é™å¹…值。 The frequency limit is a protection function that prevents the device from malfunctioning or the external frequency setting signal source is faulty, causing the output frequency to be too high or too low to prevent damage to the device. In the application, it can be set according to the actual situation. This function can also be used for speed limit. If there are some belt conveyors, because there is not much material to be transported, in order to reduce the wear of machinery and belts, the inverter can be driven and the upper limit frequency of the inverter can be set to a certain frequency value. This allows the belt conveyor to operate at a fixed, low working speed.
五å置频率有的åˆå«å差频率或频率å差设定。其用途是当频率由外部模拟信å·ï¼ˆç”µåŽ‹æˆ–电æµï¼‰è¿›è¡Œè®¾å®šæ—¶ï¼Œå¯ç”¨æ¤åŠŸèƒ½è°ƒæ•´é¢‘率设定信å·æœ€ä½Žæ—¶è¾“出频率的高低，
In some inverters, when the frequency setting signal is 0%, the deviation value can be applied in the range of 0 to fmax. Some inverters (such as Mingdianshe and Sanhao) can also set the offset polarity.如在调试ä¸å½“频率设定信å·ä¸º0%时，å˜é¢‘器输出频率ä¸ä¸º0Hz，而为xHz，则æ¤æ—¶å°†å置频率设定为负的xHzå³å¯ä½¿å˜é¢‘器输出频率为0Hz。
å…频率设定信å·å¢žç›Š
This function is only effective when the frequency is set with an external analog signal. It is used to compensate for the inconsistency between the external set signal voltage and the internal voltage of the inverter (+10v); at the same time, it is convenient to select the analog set signal voltage. When setting, when the analog input signal is maximum (such as 10v, 5v or 20mA), find the frequency percentage of the f/V pattern that can be output and set it as a parameter; if the external setting signal is 0~5v, if the output frequency of the inverter is 0~50Hz, the gain signal will be Set to 200%.
七转矩é™åˆ¶It can be divided into two types: drive torque limit and brake torque limit. It is based on the output voltage and current value of the inverter, and the torque calculation is performed by the CPU, which can significantly improve the shock load recovery characteristics during acceleration and deceleration and constant speed operation. The torque limit function enables automatic acceleration and deceleration control. It is assumed that the acceleration/deceleration time is less than the load inertia time, and the motor can be automatically accelerated and decelerated according to the torque set value.驱动转矩功能æ供了强大的起动转矩，在稳æ€è¿è½¬æ—¶ï¼Œè½¬çŸ©åŠŸèƒ½å°†æŽ§åˆ¶ç”µåŠ¨æœºè½¬å·®ï¼Œè€Œå°†ç”µåŠ¨æœºè½¬çŸ©é™åˆ¶åœ¨æœ€å¤§è®¾å®šå€¼å†…，当负载转矩çªç„¶å¢žå¤§æ—¶ï¼Œç”šè‡³åœ¨åŠ 速时间设定过çŸæ—¶ï¼Œä¹Ÿä¸ä¼šå¼•èµ·å˜é¢‘器跳闸。 When the acceleration time setting is too short, the motor torque will not exceed the maximum set value. A large driving torque is advantageous for starting, and it is preferable to set it to 80 to 100%. The smaller the brake torque setting value is, the larger the braking force is. It is suitable for the occasion of sudden acceleration and deceleration. If the brake torque setting value is set too high, an overvoltage alarm phenomenon will occur. If the braking torque is set to 0%, the total amount of regeneration applied to the main capacitor can be close to zero, so that when the motor is decelerating, it can be decelerated to stop without tripping without using the braking resistor. However, in some loads, if the braking torque is set to 0%, a short idling phenomenon will occur during deceleration, causing the inverter to start repeatedly, the current fluctuates greatly, and the inverter will trip if it is serious, which should be noticed.
å…«åŠ å‡é€Ÿæ¨¡å¼é€‰æ‹©åˆå«åŠ å‡é€Ÿæ›²çº¿é€‰æ‹©ã€‚Generally, the inverter has three kinds of curves: linear, nonlinear and S. Usually, most of the linear curves are selected; the nonlinear curve is suitable for variable torque loads, such as fans; the S curve is suitable for constant torque loads, and the acceleration and deceleration changes are relatively slow. According to the load torque characteristics, the corresponding curve can be selected according to the load torque characteristics. However, when debugging the inverter of a boiler induced draft fan
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