Hybrid-Bridge-Based DAB Converter with Voltage Match Control for Wide Voltage Conversion Gain Applic

Abstract

This paper proposes a voltage match (VM) control for hybrid-bridge-based dual active bridge (DAB) converter in wide voltage conversion gain applications. With the addition of an auxiliary half bridge circuit, the topology becomes an integration of a half-bridge and a full-bridge DAB converter. Unlike other PWM generation method for DAB converters, this converter utilizes four-level voltage at one port of the transformer to obtain matched voltage waveforms within the range of twice the minimum conversion gain. Wide conversion gain, decoupling of the two power control variables and wide zero voltage switching (ZVS) ranges can be achieved with the proposed voltage match control. Full load ranges of ZVS for the six main power switches can be achieved and the two auxiliary switches can also operate in a wide ZVS range. In addition, the power control is done only using two control variables and its implementation is very simple, only needing a divider and a conventional voltage regulator.

Existing System

Modulation.

Proposed System

In this paper, to achieve wide voltage gain for bidirectional power flow applications, a voltage match (VM) control is proposed for hybrid-bridge-based DAB converter. The topology has been inspired and is derived from adding two switches and two split capacitors to the DAB topology. Unlike other DAB converters employing two or three level voltage waveform modulation, it utilizes four level voltage waveforms at one port of the transformer to achieve wide ZVS range for all the switches within the range of twice the minimum conversion gain. Besides, the power control is simplified as it is only related to two control variables since duty cycle for the other bridge can be fixed as 0.5. As a result, a half bridge instead of full bridge circuit can be employed to simplify topology without affecting the merits of wide ZVS range and wide voltage conversion gain. The controller is simple and can be easily implemented by digital control.

Architecture

Topology of hybrid-bridge-based DAB converter