Multiple-inverter parallel control method for quickly restraining harmonic circulating current

Abstract

The invention discloses a multiple-inverter parallel control method for quickly restraining harmonic circulating current. The method comprises the following steps: obtaining harmonic circulating current of output current of inverters by adopting an ip-iq algorithm, reversing the phase of the harmonic circulating current to be superposed to a voltage loop to be output to obtain an instruction of a current regulating loop, so that the harmonic circulating current of the output current of the inverters can be efficiently and quickly restrained, and the fact that the harmonic circulating current is restrained through parallel connection of multiple inverters is realized. The invention further provides a variable-window computing method for the moving average power to improve the average power calculation, reduce deviation caused by conventional fixed period calculation and improve the calculating accuracy for average power; with the moving average calculation, the average power can be calculated once in each sampling period, so that the real-time property for power calculation is greatly improved, the power sharing can be well realized through performing droop control on power, the harmonic circulating current can be further reduced. The multiple-inverter parallel control method for quickly restraining the harmonic circulating current can be widely applied to a multiple-inverter parallel control system of a microgrid, and especially suitable for a microgrid with nonlinear load operation.

Description

technical field [0001] The invention relates to the technical field of multi-inverter parallel control of a microgrid, in particular to a multi-inverter parallel control method for fast harmonic circulation suppression. Background technique [0002] With the increasingly severe global energy crisis and environmental pollution, people pay more and more attention to the development and utilization of new energy. As a widely distributed and efficient clean energy, new energy will replace traditional energy more and more. At present, new energy power generation is considered to be the most promising new energy technology in the world, and countries have invested huge sums of money in research and development, and vigorously expand its market application. As an effective means for the development and utilization of new energy, microgrid can efficiently utilize distributed power. [0003] A key issue in the operation of the microgrid is the parallel operation of multiple inverter...

AI Technical Summary

Problems solved by technology

At present, the method of virtual impedance is generally used to reduce the circulating current, and the suppression effect on the fundamental circulating current is better, but it is difficult to suppress the harmonic circulating current, and it will even increase the distortion rate of the inverter output voltage.

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