Single-stage isolated bidirectional converter and control method thereof

Abstract

The present invention provides a single-stage isolated bidirectional converter and its control method. The converter includes: a first full-bridge circuit unit, a half-bridge circuit unit, a second full-bridge circuit unit, and a phase-shifting inductance unit , a transformer and a filter capacitor, the transformer includes a first winding and a second winding, the first winding is provided with a center tap, the center tap is connected to the first port, and the two ends are respectively connected to the first full bridge circuit unit through the phase-shifting inductance unit. The two ends of the second winding are respectively connected to the midpoints of the two bridge arms of the second full-bridge circuit unit; the two ends of the first full-bridge circuit unit are respectively connected to the two ends of the half-bridge circuit unit. The two ends of the half-bridge circuit unit are also connected to the two ends of the filter capacitor, and the midpoint of the bridge arm is connected to the second port; the two ends of the second full-bridge circuit unit are respectively connected to the third port and the fourth port connected. Therefore, the conversion efficiency and service life of the converter are improved, and the volume is small.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a single-stage isolated bidirectional converter and a control method thereof. Background technique [0002] Isolated bidirectional converter (AC / DC bidirectional converter) is a power electronic device used for electric energy conversion, which can work in rectification mode and inverter mode, provides energy transmission between AC and DC, and provides electrical isolation through a transformer. Isolated AC / DC bidirectional converters can be used in driving motors, electric vehicle power battery charging and discharging, lithium battery energy storage and other fields. [0003] In related technologies, most isolated AC / DC bidirectional converters adopt a two-stage structure, which consists of a first-stage bidirectional non-isolated AC / DC converter and a first-stage bidirectional isolated DC / DC converter, and the two stages are connected in parallel The DC bus capacit...

AI Technical Summary

Problems solved by technology

However, the two-stage isolated AC / DC bidirectional converter has the following disadvantages: (1) When using the above-mentioned two-stage isolated AC / DC bidirectional converter, due to the power transmission between the AC port and the DC port, it needs to go through Two conversions can be completed, so the conversion efficiency is low; (2) In the two-stage isolated AC / DC bidirectional converter, the bus capacitor needs to be used as the energy buffer unit of the two-stage converter, and the required capacitance is relatively high. Aluminum electrolytic capacitors are used, but the aluminum electrolytic capacitors are large in size and short in life, resulting in a large size and short service life of the two-stage isolated AC / DC bidirectional converter; (3) bidirectional non-isolated AC / DC The DC converter needs to use a Boost inductor with a large inductance to reduce the current ripple, thereby reducing the electromagnetic interference conducted to the AC terminal, and reducing the power loss on the semiconductor switch tube and inductor

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