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The setting of common parameters of frequency converter
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The setting of common parameters of frequency converter1 control mode converter xml:namespace prefix
It is determined by the load torque characteristics, the motor mechanical load torque characteristics by the formula: P=Tn/9550: P: motor power kW. T: motor torque N*M. n: motor speed rpm. The relationship between T and the speed of N can be divided into 3 types: one is constant torque, the torque is constant when the speed changes. Such as conveyor belt, crane, etc., the constant power: the speed and torque is inversely proportional to the relationship, but the product of the two constant. Such as machine tool spindle; variable torque: torque with the speed of change according to a certain function to change the load. The wind machine pumps, etc.. When the inverter control mode of the P1300=0 inverter is U/F, it can adapt to most of the constant torque load. If the load is fan, pump P1300=1. In VVVF system may happen resonance phenomenon, resulting in the system work abnormally and mechanical damage. Therefore, the inverter provides a function of frequency hopping, P1091~P1094 for set to jump frequency P1101 for setting the frequency hopping bandwidth, so as to avoid resonance. When P1300=3 converter in programming of the U / F control mode P1320.P1322.P1324 provides a programmable frequency coordinate. P1321.P1323.P1325 provides a programming voltage reference, which can at a particular frequency for the motor to provide the specific torque to adapt to load changes. Vector control is modeled by a DC motor control method for induction motor control. Firstly, the stator currents through coordinate conversion into excitation current component and armature current component and respectively on the two control. Therefore, the mechanical properties of the motor are very hard and have very high dynamic response capability. According to the need of P1300=20/21 / P1300=22/23 / no feedback vector control or vector torque control to meet the load control accuracy.
2 acceleration / deceleration time
Acceleration time is defined as the time required for the output frequency to rise from 0 to the maximum frequency, and the deceleration time is defined as the time required for the output frequency to be reduced to 0. The reasonable or not of the time setting of acceleration / deceleration is a great influence on the starting and stopping of the motor and the speed change of the speed regulation system. The acceleration time should be set up to limit the stator current of the motor to the rated current of the converter without the action of the overcurrent protection device. Motor deceleration in regeneration power brake state, feedback the energy through diode reverse transmitted to the DC link electrolytic capacitor by flywheel used on the inverter, thus making it on both ends of the voltage is increased. Therefore, the setting of the deceleration time is the voltage of the DC bus is no more than the over voltage alarm value. The calculation formula of the acceleration time: ta= (Jm+Jl) *n/ (9.56* (Tma-Tl)) formula of deceleration time: tb= (Jm+Jl) *n/ (9.56* (Tmb-Tl)) type: Jm: Jl: motor inertia load inertia. Speed n: motor drive torque motor Tma: Tmb: Tl: motor braking torque load the torque / deceleration time can be calculated by the formula, but also can be calculated by empirical method: firstly, the drive system is running at full speed (frequency of 50 Hz), and then cut off the power supply to drive system in the braking state, with a stopwatch, measure the speed is reduced to 0RPM the time required, i.e. you can know the size of the moment of inertia. The usual time constant can be chosen for the 1/5~1/3 of the free time. In the end of the process, the frequency converter has no flow or over voltage alarm, the setting value of the acceleration / deceleration time is adjusted, and the optimal time constant is determined by the principle of no alarm.
3 set of moment of inertia
Motor and rotational inertia load is often neglected, think that as long as the acceleration / deceleration time setting is right, you can guarantee the normal work of the system, in fact, if set the improper lead to system shock or inverter alarm and so on. Rotary inertia formula: J=T/ (D /dt.T) T: motor torque. Motor and load inertia method to obtain: first let inverter working in the appropriate frequency, such as: 5 Hz to 10 Hz, respectively, so that the motor no-load and load running, read parameters r0333 rated torque of the motor and r0345 motor starting time, and set parameters P0341 motor rotational inertia and P0342 driving unit of the total inertia and the inertia of motor. Such variable frequency speed control system can achieve satisfactory results.
4 rapid debugging
In the use of frequency converter drive motor must be a quick test. Parameters P0010=1 (began to rapid debugging); in the debugging process must be to the inverter input the correct motor nameplate parameters. In order to prevent the motor from overload and damage, the rated power of the inverter should be reasonably set up with the rated power of the motor. Data automatic detection (P1910) of the motor under the vector control mode with / without sensor feedback must be carried out in cold (normal temperature). If there is a lot of difference between the ambient temperature and the default value (20), the P0625 (motor running ambient temperature) should be set to the actual temperature value. P3900=3 (the end of the fast debugging, and the calculation of motor not only of I / O reset) is connected to motor parameter automatic detection, when the completion detection alarm A0541 disappear automatically, the inverter into "ready for operation" state.
5 dynamic buffer function
This function is used to define the voltage drop or the transient voltage
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