Parallel inverter drive system and its circulation suppression device and method

Abstract

The invention provides a parallel inverter drive system and circulating current restraining device and method therefor. The parallel inverter drive system comprises a plurality of parallel inverter drivers, a PWM (pulse width modulation) controller and a circulating current retraining device. Each inverter driver comprises a switching device. The PWM controller controls switching of the switching devices connected with the same according to a duty ratio signal. The circulating current retraining device is connected between output ends of the switching devices and an input end of the PWM controller to collect feedback phase current of each driver and current information related to summation current, generates an indicator according to the to-be-achieved circulating current volume and / or zero-sequence current volume of the drive system and the current information, generates zero-sequence voltage in each phase to inject a phase voltage instruction in a forward configuration mode according to the indicator, the voltage instruction of each driver and the operating mode of the driver, and accordingly corrects the phase voltage instruction. The PWM controller generates the duty ratio signal according to the corrected phase voltage instruction output by the restraining device.

Description

technical field [0001] The present invention relates to a parallel inverter drive system for driving a motor, in particular to a device and method for suppressing circulating current in the parallel inverter drive system. Background technique [0002] Generally speaking, a motor requires an inverter drive to control the frequency change of the rotor magnetic field of the motor and adjust the rotational speed of the motor, thereby driving the operation of the motor. In order to increase the safety of the motor during operation, a parallel inverter system has been proposed, which is to connect the outputs of multiple inverter drivers in parallel to drive the motor. The biggest difference between the parallel inverter drive system and the general inverter drive system is that the single large-capacity inverter drive corresponding to the motor is replaced by multiple inverter drives with smaller capacity, and this group of smaller-capacity inverter drives Inverter driver common...

AI Technical Summary

Problems solved by technology

At this time, if this current drooping technology is used for control, the current output will be greatly suppressed, thereby reducing the instantaneous response and slowing down the acceleration of the motor speed.

Finally, this technique suffers from the same drawbacks as the previously described technique of using current-sharing configurations to achieve circulation suppression

In other words, this technology only simplifies the way of current sharing and achieves a higher degree of modularity, but the shortcomings are still not improved

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