Control device and method for inverter parallel system based on pulse width modulation wave reconstruction

Abstract

The invention discloses an inverter parallel system control method based on pulse duration modulated wave reconstitution. The method includes the following steps that 1 the frequency of pulse duration modulated waves is calculated according to the requirement of an inverter, and the frequency is set as the control period frequency of a master controller and modulated wave frequency of slave controllers; 2 signals of voltage, electricity, and the like of the inverter are acquired through a signal acquiring unit and signal filtering is carried out; 3 comparator parameters of the space vector modulated wave are calculated by a master control unit in a pulse duration modulated wave period; 4 the comparator parameters and synchronizing signals are encoded by a signal programming unit and broadcast to all the slave controllers in a serial mode; 5 the comparator parameters and synchronizing signals are received and encoded by the slave controllers, and signal reconstitution pulse duration modulated wave signals encoded serve as driving signals of power devices. Synchronism and consistency of the driving signals of each power device are guaranteed by the control method based on the pulse duration modulated wave reconstitution inverter parallel system. Zero-sequence circle current of the inverter in parallel is essentially removed and reliability of the system is improved.

Description

technical field [0001] The present invention relates to the field of three-phase inverter control, in particular to a control device and method for an inverter parallel system based on pulse width modulation wave reconstruction, Background technique [0002] At present, the cost of generating electricity from renewable energy such as wind energy and solar energy is too high, and the entire industry relies on state subsidies to survive. Affected by the international financial crisis, many European countries have reduced or canceled state subsidies, which has severely damaged related industries, and many related companies have gone bankrupt. Reducing the cost per kilowatt-hour of power generation, improving power generation efficiency, and making it truly competitive in the market are huge challenges for the renewable energy industry. Developing low-cost, high-capacity renewable energy power generation systems is one of the effective ways to achieve the above goals, and inver...

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Problems solved by technology

[0003] At present, the parallel control technology of inverters mainly includes three control methods: master-slave control, distributed control and droop control. In particular, it is difficult to keep the voltage amplitude, waveform and phase of each power module consistent during dynamic conditions, making the existing control strategy ineffective. Reduce the current sharing inductance of the parallel system, which seriously restricts the promotion and application of inverter parallel technology

Patent application number 201310123180.8 discloses a method for the control system of the inverter to send a synchronous enabling signal to the signal output arbiter, but the method can only ensure the synchronization of the triangular carrier wave, and cannot solve the problem of different pulse width modulation waves of each inverter. zero-sequence circulating current

Patent application number 200810074029.9 discloses a parallel control method for inverters. This method controls the output voltage amplitude, phase and DC component of the output voltage of each inverter, and divides the load equally. The pulse width modulation wave is still controlled by each inverter. The inverter control unit is calculated, but due to the existence of calculation errors and sampling errors, the consistency of the drive signals of the power devices of each control unit cannot be achieved

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