Download A High Step-up Bidirectional Isolated Dual-Active

A High Step-up Bidirectional Isolated Dual-ActiveBridge Converter with Three-Level Voltage-Doubler
Rectifier for Energy Storage Applications
Abstract:
A bidirectional isolated dual-active-bridge (DAB) converter with three-level
voltage-doubler rectifier (TL-VDR) is presented for energy storage applications.
The voltage conversion ratio is enhanced and the voltage stresses on transformer
windings are reduced with the help of TL-VDR. Optimized pulse widthmodulation (PWM) plus dual phase-shift-modulation (PSM) strategy is applied to
the presented DAB converter. The circulating current is reduced and the softswitching performance is achieved in wide voltage and load range. Therefore, high
efficiency bidirectional step-up/step-down power conversion is achieved with the
presented topology and control strategy. These features make the presented
converter attractive for energy storage applications. The operation principles and
characteristics are analyzed and verified with experimental results.
Existing system:
 A high step-up bidirectional DC-DC converter is required to control
bidirectional power transfer of the energy storage devices. Thus, high
efficiency bidirectional DC-DC converters have attracted much interest in
energy storage systems.
 A dual active- bridge (DAB) converter is attractive for isolated bidirectional
power conversion due to its symmetric structure and zero voltage switching
performance. However, this converter has a limited ZVS range and high
circulating current under wide voltage variation.
Proposed system:
 A novel bidirectional DAB converter utilizing a three-level voltage-doubler
rectifier (TL-VDR) on the high voltage side is proposed in this paper.
 With PWM plus dual phase-shift-modulation (PSM) control, soft-switching
for all switches can be realized over a wide range, which helps to reduce
switching losses.
 The TL-VDR can be employed to reduce the circulating current by
generating a trapezoidal three level in the high-voltage side, which
contributes to reduce conduction losses.
Circuit diagram:
Reference:
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