Double step-up/double step-down combined AC/AC converting circuit

Abstract

Disclosed is dual booster / dual buck combination AC-AC conversion circuit which belongs to the AC-AC frequency conversion technology. The circuit includes a power supply, two booster bridge circuits (1, 3), two buck bridge circuits (5, 7), a DC section circuit (4) in the middle and an output filtering circuit (6). The two booster bridge circuits form a dual booster PWM rectifying circuit; the second booster bridge circuit works at the positive half cycle of the input current and the first booster bridge circuit works at the negative half cycle of the input current. The two buck bridge circuits form the dual buck circuit; the first buck bridge circuit works at the positive half cycle of the input current and the second buck bridge circuit works at the negative half cycle of the input current. The dual booster PWM rectifying circuit and the dual buck circuit all adopt the current hysteresis control method which has the ability of automatic current limit and has fast dynamic response. The dual booster / dual buck combination AC-AC conversion circuit of the invention is suitable for the medium and large power field with high efficiency, such as the airplane frequency conversion power supply, UPS, new energy electricity generation which have unified surge control and active filtering.

Description

technical field [0001] The invention relates to a dual boost / double buck combined AC-AC conversion circuit, which belongs to the AC-AC frequency conversion technology in electric energy conversion devices. Background technique [0002] At present, the frequency conversion AC power supply technology has many advantages such as fewer system components, simple structure, high efficiency, light weight, small size, low cost, high reliability, and good maintainability. Compensation (SVG), unified power flow controller (UPFC), superconducting magnetic energy storage (SMES), four-quadrant AC motor drive, grid-connected power generation of renewable energy such as solar energy and wind energy, active power filter (APF), large-capacity UPS And many other occasions have been widely used. [0003] In modern aircraft, the variable frequency AC power system has replaced the traditional variable speed constant frequency power system and constant speed constant frequency power system. Bec...

AI Technical Summary

Problems solved by technology

The main disadvantage of this circuit topology is: the switch tubes are connected in series, and there is a hidden danger of the switch tubes being short-circuited.

At the same time, the freewheeling diode of this circuit is the parasitic diode of the switching tube, and its reverse recovery time is quite long, resulting in a large reverse recovery loss

These two problems have affected the reliability and conversion efficiency of this PWM AC-AC conversion circuit.

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