Three-level double step-down full bridge inverter

Abstract

The invention relates to a three-voltage dual-reduction full-bridge inverter, wherein it comprises power circuit (1), two reduction circuits (2, 3), filter capacitors and load circuit (4), and work-frequency switch circuit (5); the inputs of circuits (2, 3) are connected to circuit (1), while outputs are connected to filter capacitor and load circuit (4). The invention is characterized in that: the ground part of filter capacitor (Cf) via two switch tubes is connected to the anode and the cathode of bus voltage; the external bus voltage is reduced from 2Ud to Ud. The invention has simple structure and control method.

Description

1. Technical field [0001] The invention relates to a three-level double-step-down full-bridge inverter, which belongs to an inverter in an electric energy conversion device. 2. Background technology [0002] With the development of power electronics technology, power converters are developing in the direction of high frequency and high efficiency. At the same time, many applications such as aerospace and UPS have put forward high requirements for power supply reliability. In traditional bridge inverter circuits, because the switch tubes are directly connected in series, there is a potential for the bridge arm to pass through, and an additional control dead zone is required, and this dead zone will cause distortion of the output voltage waveform. At the same time, the body diode of the switching tube in the bridge circuit participates in the work. For MOS devices, measures to improve MOSFET performance often lead to poor body diode performance, and it is difficult to optimiz...

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Problems solved by technology

[0004] DBHBI and half-bridge inverters (hereinafter referred to as half-bridge inverters) also have the following disadvantages: the voltage stress of the device is twice the input voltage, and it is difficult to apply in high-voltage input applications; the bridge arm can only output + 1 and -1 two-state level, working in bipolar modulation mode, the output waveform of the bridge arm has a large harmonic content, which requires high switching frequency and a large filter; the DC side needs a large capacitor to share the bus voltage equally, or The input voltage itself is required to provide positive and negative bus voltage and ground, which is not satisfied in most applications

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