A bidirectional high-gain non-isolated converter and its control method

Abstract

The invention discloses a bidirectional high-gain non-isolated converter, belonging to the technical field of a power electronic converter. The bidirectional high-gain non-isolated converter comprises five switching tubes, two coupling inductors, a high-frequency inductor and three capacitors, the two coupling inductors respectively comprises a low-voltage side winding and a high-voltage side winding, the low-voltage side windings of the two coupling inductors are connected in parallel for charging and are connected in series for discharging, and the high-voltage side windings of the two coupling inductors are connected in series for working all the time. Through the series-parallel connection structure of the coupling inductors, the bidirectional high-gain non-isolated converter disclosed by the invention has the ability of high gain specific voltage conversion; with the adoption of duty cycle and phase shift control, controllable bidirectional power transmission of the bidirectional high-gain non-isolated converter can be achieved; and moreover, soft switching of all switching tubes can be achieved, thus, the switching loss can be effectively reduced, and the efficiency is improved. The bidirectional high-gain non-isolated converter is particularly applicable for an occasion with high frequency, high gain and non-isolated bidirectional DC power conversion.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to the technical field of bidirectional non-isolated DC-DC power conversion. Background technique [0002] The bidirectional DC converter is one of the core devices in power supply systems such as renewable energy power generation, electric vehicles, and energy storage systems. Adjustment and other control functions. [0003] Due to the low output voltage of the energy storage battery (typically 12V, 24V, etc.), and the wide range of battery terminal voltages, the DC bus voltage of various distributed DC power supply systems is usually 400V or even higher in order to connect with the AC grid. . The huge difference between the battery voltage and the DC bus voltage brings great technical challenges to the bidirectional converter. First, the bidirectional converter must be able to achieve a high boost ratio and a high step-down ratio in both boost and buck modes, that is, it should...

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Problems solved by technology

That is, the duty cycle of one of the switch tubes is close to 1, and the duty cycle of the other switch tube is close to 0. The two switch tubes must bear the high current of the low-voltage side and the high voltage of the high-voltage side at the same time. The voltage and current stress of the switch tube sharply increased, resulting in a substantial decrease in efficiency

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