Modular parallel driving system and control method thereof

Abstract

The invention relates to a modular parallel driving system and a control method thereof. A plurality of driver modules are connected in parallel so as to form the modular parallel driving system; the direct-current bus terminals of the driver modules are connected together sequentially; the power end UVW output of the driver modules passes through a current equalizing reactor and thereafter is connected in parallel with the UVW ends of a motor; and in the driver modules which are connected sequentially, the first driver module is adopted as a master module, and the other driver modules are adopted as slave modules, all the structures of the master module and the slave modules except inner control modules are the same. According to the modular parallel driving system and the control method thereof of the invention, the core components of the system are the drivers of a modular structure; alternating-current three-phase input and direct-current input of a rectifier are supported; the capacity expansion of the system is realized through parallel connection of a plurality of modules; and the parallel-connected system adopts a "hard parallel" control strategy. The system has the advantages of simple control strategy, excellent dynamic performance and suitability for product engineering application. According to the parallel-connected system, the master module and the slave modules can realize the synchronization of fundamental wave modulation through synchronous signals.

Description

technical field [0001] The invention belongs to the field of power electronics and motor control, relates to a motor drive system, is widely used in high-power AC motor speed regulation, and is a modularized parallel drive system and a control method thereof. Background technique [0002] In order to meet the increasing requirements of the capacity of the motor drive system, parallel three-phase inverters are used to increase the capacity of the motor speed control system. Parallel connection methods include: 1) The DC side is powered by multiple power sources independently, and the AC side outputs a series current sharing reactor directly and then connected in parallel; 2) The DC side is directly connected in parallel with a DC power supply, and the AC side is connected in parallel after passing through an isolation transformer; parallel connection mode (1 ) and (2) require an independent DC power supply or an isolation transformer, which brings problems such as system volu...

AI Technical Summary

Problems solved by technology

[0005] Chinese Patent Invention CN103560746A "A Multi-Parallel Inverter Motor Speed ​​Control System and Its Control Method" proposes a multi-parallel inverter motor speed control system, which does not propose to use any communication technology to connect multiple inverters. Control signals and current feedback signals are transmitted

The control strategy used in this patent actually requires i d i q For circulation suppression adjustment, when the number of parallel units increases to a certain number, the algorithm is extremely complicated and it is difficult to product engineering

This patent proposes a multi-parallel inverter motor speed control method using random PWM technology. The PWM duty cycle output by each inverter module used in this control technology is inconsistent, and the harmonic component of the motor line voltage will increase, and Since each driver is regulating the motor Iq current affected by the circulating current, it is very likely to run out of control and cannot achieve a stable state

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