Three-phase isolating type bidirectional AC-DC converter and control method therefor

Abstract

The invention discloses a three-phase isolating type bidirectional AC-DC converter and a control method therefor, and belongs to the technical field of a power electronic converter. The converter comprises an alternating current side filter, a three-phase rectifying / inverter bridge, an alternating current side switch circuit, a high frequency isolating transformer unit, an active magnetic reset circuit, a direct current side switch circuit and a direct current side filter; the working state of the high frequency transformer in the converter is similar to normal shock; the voltage pressure of a direct current side switch tube is reduced by adopting the active magnetic reset mode; the control method adopts an improved current type SVPWM (space vector pulse width modulation) method to enable the alternating current side switch to work at a low frequency, so that the loss of the alternating current side switch is reduced; and the bidirectional converter has the characteristics of wide output voltage scope, free of a direct current bus, and capability of realizing electric isolation, so that the converter is suitable for being used as an interface converter between a power grid and a storage battery.

Description

technical field [0001] The invention discloses a three-phase isolated bidirectional AC-DC converter and a control method thereof, especially an isolated bidirectional AC-DC converter and its improved current type SVPWM ( SpaceVectorPulseWidthModulation, a space vector pulse width modulation) method, belongs to the technical field of power electronic converters. Background technique [0002] In the AC micro-grid system, the power generation of new energy such as photovoltaics and wind power shows great fluctuations due to the influence of natural conditions, and the power grid itself does not have the function of storing energy, so energy storage devices are needed to maintain the power balance of the system and Stable, the battery has been widely used in the microgrid system due to its large storage energy, convenient installation and cost advantages. The battery is directly connected to the microgrid through an interface converter. During the peak period of power consumpti...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a three-phase isolated bidirectional AC-DC converter and its control method for some deficiencies in the above-mentioned background technology, so that the three-phase rectification / inverter bridge and the bidirectional switch circuit on the AC side The switch tube works in low frequency mode, which reduces the switching loss of the switch tube on the AC side. The magnetic reset method of the transformer is active magnetic reset to reduce the voltage stress of the switch tube on the DC side, which solves the two-stage converter. Two energy conversions And the technical problem that the high-frequency operation of the traditional space vector control AC side switching tube is not conducive to efficiency improvement

Images