Sine wave inverter capable of working in parallel and controlling method thereof

Abstract

The invention relates to a sine wave inverter which can work in parallel and a control method thereof, belonging to a sine wave inverter. Including inverter circuit and inverter control circuit, the inverter control circuit includes PLC chip and its peripheral control circuit, power line, PLC and synchronous control DSP, inverter and current sharing control DSP, voltage sampling and shaping circuit, output voltage sampling circuit , Output current sampling circuit, drive control circuit. PLC and synchronous control DSP adjust the voltage reference sinusoidal signal of each inverter to keep the same frequency and phase. Calculate the power difference by power, and use the power difference to fine-tune the phase and amplitude of the reference signal respectively to realize current sharing control. The invention does not need signal interconnection wires, has strong communication immunity and high reliability, and is applied to a sine wave inverter control system without signal interconnection wires to realize complete electrical isolation and hot swapping of each inverter.

Description

1. Technical field [0001] The invention belongs to the technical field of parallel control of sine wave inverters, and in particular relates to a method and realization technology for parallel operation of single-phase and three-phase sine-wave inverters, single-phase and three-phase on-line uninterruptible power supplies (UPS), and the like. 2. Background technology [0002] The control block diagram of an existing sine wave inverter that can work in parallel is as follows: figure 1 As shown, it includes two parts: a power unit composed of an inverter circuit and an inverter control unit. The inverter control unit mainly includes a voltage sampling and shaping circuit, an output voltage sampling circuit, a reference sinusoidal signal generator, a voltage regulator and a drive control circuit. ; It is characterized in that it also includes a synchronous control unit connected between the voltage sampling and shaping circuit and the reference sinusoidal signal generator and a...

AI Technical Summary

Problems solved by technology

[0005] The main disadvantage of this parallel scheme is that the same-frequency and same-phase control of the square-wave synchronous signals of each parallel inverter must be completed through two signal interconnection lines between each inverter, and the existence of signal interconnection lines still increases the The hardware complexity of the system reduces the reliability of the system

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