The inverter itself has many parameters that need to be set correctly, and each parameter has a certain range of choices. In use, it often happens that the inverter cannot work normally due to improper setting of individual parameters. Therefore, the relevant parameters must be set correctly.
1. Control mode:
Namely speed control, torque control, PID control or other methods. After the control method is adopted, it is generally necessary to carry out static or dynamic identification according to the control accuracy.
2. Minimum working frequency:
That is, the minimum running speed of the motor, the heat dissipation performance of the motor is poor when running at low speed, and the motor will burn out if it runs at low speed for a long time. And at low speeds, the current in the cable increases, which also causes the cable to heat up.
3. Maximum working frequency:
The maximum frequency of ordinary inverters is as high as 60Hz, and some are even as high as 400 Hz. High frequency will make the motor run at high speed. For ordinary motors, their bearings cannot run at a constant speed for a long time. Can the rotor of the motor withstand such centrifugal force?
4. Carrier frequency:
The higher the carrier frequency is set, the greater the high-order harmonic component, which is closely related to factors such as cable length, motor heating, cable heating, and inverter heating.
5. Motor parameters:
The inverter sets the power, current, voltage, speed and maximum frequency of the motor in the parameters, which can be obtained directly from the nameplate of the motor.
6. Frequency Hopping:
At a certain frequency point, resonance may occur, especially when the whole device is relatively high; when controlling the compressor, avoid the surge point of the compressor.
7. Acceleration and deceleration time
The acceleration time is the time required for the output frequency to rise from 0 to the maximum frequency, and the deceleration time is the time required for the output frequency to decrease from the maximum frequency to 0. Acceleration and deceleration times are usually determined by the rise and fall of the frequency setting signal. When the motor is accelerating, it is necessary to limit the rising rate of the frequency setting to prevent overcurrent, and when decelerating, it is necessary to limit the falling rate to prevent overvoltage.
Requirements for setting the acceleration time: limit the acceleration current below the overcurrent capacity of the inverter, so as to avoid tripping of the inverter due to overcurrent speed; the key point of setting the deceleration time is to prevent the voltage of the smoothing circuit from being too high, so as to avoid tripping the inverter due to regenerative overvoltage stall device. The acceleration and deceleration time can be calculated according to the load, but when debugging, it is often necessary to set a longer acceleration and deceleration time according to the load and experience, and observe whether there is an over-current or over-voltage alarm by turning off the motor; then gradually shorten the setting time of the acceleration and deceleration, Under the principle of no alarm during operation, the best acceleration and deceleration time can be determined by repeating several operations.
8. Torque increase
Also known as torque compensation, it is a method to increase f/V in the low frequency range to compensate for the low-speed torque reduction caused by the motor stator winding resistance. When set to auto, the voltage during acceleration can be automatically increased to compensate for the starting torque, allowing the motor to accelerate smoothly. If manual compensation is used, a better curve can be selected through experiments according to the load characteristics, especially the load start-up characteristics. For variable torque loads, if the selection is improper, the output voltage will be too high at low speed, resulting in waste of electric energy, and even the current will be large when the motor starts with load, but the speed will not increase.
9. Electronic thermal overload protection
This function is set to prevent the motor from overheating. The CPU in inverter calculates the temperature rise of the motor according to the operating current value and frequency to protect the motor from overheating. This function is only applicable to “one-to-one” occasions, and in the case of “one-to-many”, a thermal relay should be installed on each motor.
Electronic thermal protection setting value (%)=[motor rated current (A)/inverter rated output current (A)]×100%.
10. Frequency limitation
That is, the upper limit and lower limit clipping value of the inverter output frequency. Frequency limit is a protection function to prevent the output frequency from being too high or too low due to misoperation or failure of the external frequency setting signal source, thereby preventing equipment damage. It can be set according to the actual situation in the application. This function can also be used as a speed limiter. For some belt conveyors, since there are not many materials to be transported, in order to reduce the wear of machinery and belts, frequency converters can be used to drive, and the upper limit frequency of the frequency converter can be set to a certain frequency value, so that the belt conveyor can Runs at a fixed low operating speed.
11. Offset Frequency
Some are also called offset frequency or frequency offset settings. Its purpose is to adjust the output frequency when the frequency is set by an external analog signal (voltage or current). For some inverters, when the frequency setting signal is 0%, the deviation value can be in the range of 0 ~ fmax, and some inverters (such as mingdianshe and sanken) can also set the bias polarity. If the output frequency of the inverter is xHz instead of 0Hz when the frequency setting signal is 0% during debugging, then setting the offset frequency to negative xHz can make the output frequency of the inverter 0Hz.
12. Frequency setting signal gain
This function is only valid when using an external analog signal to set the frequency. It is used to make up the inconsistency between the external setting signal voltage and the internal voltage (+10v) of the inverter. At the same time, it is convenient to select the analog setting signal voltage. When setting, when the analog input signal is the largest (such as 10v, 5v or 20mA), calculate the frequency percentage of the output f/V diagram and set it as a parameter; if the external setting signal is 0 ~ 5v, the output frequency of the inverter is 0 ~ 50hz , the gain signal can be set to 200%.
13. Torque limit
It can be both drive torque limit and brake torque limit. According to the output voltage and current value of the inverter, the torque is calculated by the CPU, which can significantly improve the impact load recovery characteristics during acceleration, deceleration and constant speed operation. The torque limit function can realize automatic acceleration and deceleration control. Assuming that the acceleration and deceleration time is less than the load inertia time, the motor can automatically accelerate and decelerate according to the torque setting value.
The drive torque function provides strong starting torque. During steady state operation, the torque function will control motor slip and limit motor torque to a maximum set point. When the load torque increases suddenly, even if the acceleration time is set too short, it will not cause the inverter to trip. When the acceleration time is set too short, the motor torque will not exceed the maximum setting value. A large driving torque is conducive to starting, and it is best to set it at 80-100%.
The smaller the braking torque setting value is, the greater the braking force is, which is suitable for rapid acceleration and rapid deceleration. For example, if the setting value of the braking torque is set too large, an overpressure alarm will appear. If the brake torque is set to 0%, the total amount of regeneration added to the main capacitor can be close to 0 so that when the motor slows down, it can slow down to a standstill without tripping. However, on some loads, such as when the braking torque is set to 0%, there will be a short idling phenomenon during deceleration, which will cause the inverter to start repeatedly and the current fluctuates greatly. In severe cases, the frequency converter will trip, so please pay attention.
The inverter itself has many parameters that need to be set correctly, and each parameter has a certain range of choices. In use, it often happens that the inverter cannot work normally due to improper setting of individual parameters. Therefore, the relevant parameters must be set correctly.
1. Control mode:
Namely speed control, torque control, PID control or other methods. After the control method is adopted, it is generally necessary to carry out static or dynamic identification according to the control accuracy.
2. Minimum working frequency:
That is, the minimum running speed of the motor, the heat dissipation performance of the motor is poor when running at low speed, and the motor will burn out if it runs at low speed for a long time. And at low speeds, the current in the cable increases, which also causes the cable to heat up.
3. Maximum working frequency:
The maximum frequency of ordinary inverters is as high as 60Hz, and some are even as high as 400 Hz. High frequency will make the motor run at high speed. For ordinary motors, their bearings cannot run at a constant speed for a long time. Can the rotor of the motor withstand such centrifugal force?
4. Carrier frequency:
The higher the carrier frequency is set, the greater the high-order harmonic component, which is closely related to factors such as cable length, motor heating, cable heating, and inverter heating.
5. Motor parameters:
The inverter sets the power, current, voltage, speed and maximum frequency of the motor in the parameters, which can be obtained directly from the nameplate of the motor.
6. Frequency Hopping:
At a certain frequency point, resonance may occur, especially when the whole device is relatively high; when controlling the compressor, avoid the surge point of the compressor.
7. Acceleration and deceleration time
The acceleration time is the time required for the output frequency to rise from 0 to the maximum frequency, and the deceleration time is the time required for the output frequency to decrease from the maximum frequency to 0. Acceleration and deceleration times are usually determined by the rise and fall of the frequency setting signal. When the motor is accelerating, it is necessary to limit the rising rate of the frequency setting to prevent overcurrent, and when decelerating, it is necessary to limit the falling rate to prevent overvoltage.
Requirements for setting the acceleration time: limit the acceleration current below the overcurrent capacity of the inverter, so as to avoid tripping of the inverter due to overcurrent speed; the key point of setting the deceleration time is to prevent the voltage of the smoothing circuit from being too high, so as to avoid tripping the inverter due to regenerative overvoltage stall device. The acceleration and deceleration time can be calculated according to the load, but when debugging, it is often necessary to set a longer acceleration and deceleration time according to the load and experience, and observe whether there is an over-current or over-voltage alarm by turning off the motor; then gradually shorten the setting time of the acceleration and deceleration, Under the principle of no alarm during operation, the best acceleration and deceleration time can be determined by repeating several operations.
8. Torque increase
Also known as torque compensation, it is a method to increase f/V in the low frequency range to compensate for the low-speed torque reduction caused by the motor stator winding resistance. When set to auto, the voltage during acceleration can be automatically increased to compensate for the starting torque, allowing the motor to accelerate smoothly. If manual compensation is used, a better curve can be selected through experiments according to the load characteristics, especially the load start-up characteristics. For variable torque loads, if the selection is improper, the output voltage will be too high at low speed, resulting in waste of electric energy, and even the current will be large when the motor starts with load, but the speed will not increase.
9. Electronic thermal overload protection
This function is set to prevent the motor from overheating. The CPU in inverter calculates the temperature rise of the motor according to the operating current value and frequency to protect the motor from overheating. This function is only applicable to “one-to-one” occasions, and in the case of “one-to-many”, a thermal relay should be installed on each motor.
Electronic thermal protection setting value (%)=[motor rated current (A)/inverter rated output current (A)]×100%.
10. Frequency limitation
That is, the upper limit and lower limit clipping value of the inverter output frequency. Frequency limit is a protection function to prevent the output frequency from being too high or too low due to misoperation or failure of the external frequency setting signal source, thereby preventing equipment damage. It can be set according to the actual situation in the application. This function can also be used as a speed limiter. For some belt conveyors, since there are not many materials to be transported, in order to reduce the wear of machinery and belts, frequency converters can be used to drive, and the upper limit frequency of the frequency converter can be set to a certain frequency value, so that the belt conveyor can Runs at a fixed low operating speed.
11. Offset Frequency
Some are also called offset frequency or frequency offset settings. Its purpose is to adjust the output frequency when the frequency is set by an external analog signal (voltage or current). For some inverters, when the frequency setting signal is 0%, the deviation value can be in the range of 0 ~ fmax, and some inverters (such as mingdianshe and sanken) can also set the bias polarity. If the output frequency of the inverter is xHz instead of 0Hz when the frequency setting signal is 0% during debugging, then setting the offset frequency to negative xHz can make the output frequency of the inverter 0Hz.
12. Frequency setting signal gain
This function is only valid when using an external analog signal to set the frequency. It is used to make up the inconsistency between the external setting signal voltage and the internal voltage (+10v) of the inverter. At the same time, it is convenient to select the analog setting signal voltage. When setting, when the analog input signal is the largest (such as 10v, 5v or 20mA), calculate the frequency percentage of the output f/V diagram and set it as a parameter; if the external setting signal is 0 ~ 5v, the output frequency of the inverter is 0 ~ 50hz , the gain signal can be set to 200%.
13. Torque limit
It can be both drive torque limit and brake torque limit. According to the output voltage and current value of the inverter, the torque is calculated by the CPU, which can significantly improve the impact load recovery characteristics during acceleration, deceleration and constant speed operation. The torque limit function can realize automatic acceleration and deceleration control. Assuming that the acceleration and deceleration time is less than the load inertia time, the motor can automatically accelerate and decelerate according to the torque setting value.
The drive torque function provides strong starting torque. During steady state operation, the torque function will control motor slip and limit motor torque to a maximum set point. When the load torque increases suddenly, even if the acceleration time is set too short, it will not cause the inverter to trip. When the acceleration time is set too short, the motor torque will not exceed the maximum setting value. A large driving torque is conducive to starting, and it is best to set it at 80-100%.
The smaller the braking torque setting value is, the greater the braking force is, which is suitable for rapid acceleration and rapid deceleration. For example, if the setting value of the braking torque is set too large, an overpressure alarm will appear. If the brake torque is set to 0%, the total amount of regeneration added to the main capacitor can be close to 0 so that when the motor slows down, it can slow down to a standstill without tripping. However, on some loads, such as when the braking torque is set to 0%, there will be a short idling phenomenon during deceleration, which will cause the inverter to start repeatedly and the current fluctuates greatly. In severe cases, the frequency converter will trip, so please pay attention.
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