A Method for Estimating and Restraining the DC Component of the Output Voltage of a Bridge Inverter

Abstract

The invention relates to a method for estimating and suppressing the direct current component of the output voltage of a bridge inverter. A DC component suppression module is added to the three-phase bridge inverter system; since the DC component of the inverter bridge arm voltage is proportional to the DC component of the inverter output voltage, the DC component suppression module controls the inverter bridge arm voltage The DC component is 0 or close to 0 to control the DC component of the inverter output voltage. Specifically, after comparing the estimated DC component of the inverter bridge arm voltage with 0, it is compensated by the PI controller, and the output value of the PI controller is obtained by After a certain limit processing, it is superimposed on the sinusoidal reference voltage, voltage loop or current loop output of the inverter. The invention can estimate the magnitude of the DC component of the bridge arm voltage of the inverter and the DC component of the inverter output voltage, and effectively suppress the DC component output by the inverter.

Description

technical field [0001] The invention relates to the fields of electrical manufacturing technology and power supply equipment control technology, in particular to a method for estimating and suppressing a DC component of a bridge inverter output voltage. Background technique [0002] The limitation of traditional fossil energy and the problems of climate change and environmental pollution brought about by its widespread use make it difficult for the industrial and economic development model based on fossil energy to continue. Thanks to the promotion of the rapid development of renewable energy technology and information technology, the organizational structure, technical foundation and economic model of the world's energy industry are gradually changing. In this context, concepts such as distributed power generation, microgrid, smart grid, and energy internet have been proposed one after another, all with the key goal of promoting the flexible and efficient use of renewable e...

AI Technical Summary

Problems solved by technology

In addition to causing additional losses, the inverter output voltage contains a DC component, which also has the following hazards: 1) If the inverter output DC component is too large, the output filter inductor will be saturated, making the inverter unable to work normally; 2) If the inverter output With an isolation transformer, it will cause the transformer to saturate and cause the system to overcurrent; 3) The DC component will cause serious asymmetry of the nonlinear load current and damage the electrical equipment; 4) For the inverter parallel system, the DC component will cause DC circulation, reducing the System reliability; 5) When the inverter is connected to the grid, the incoming current contains a DC component, which will damage the grid

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