A bidirectional half-bridge three-level dc-dc converter current effective value minimization control method

Abstract

The invention discloses a current effective value minimizing control method for a bidirectional half-bridge tri-level DC (Direct Current)-DC converter. Three controlled quantities in a topological structure of the bidirectional half-bridge tri-level DC-DC converter are controllable, namely a primary side bridge arm middle point voltage duty ratio D1, a secondary side bridge middle point voltage duty ratio D2 and a phase shift angle Dalpha between primary side bridge arm middle point and secondary side bridge arm middle point voltage; minimized control of the current effective level is achieved under the premise that power required for transmission load is satisfied. According to the current effective value minimizing control method for a bidirectional half-bridge tri-level DC (Direct Current)-DC converter, D1, D2 and Dalpha is coordinately controlled, the current effective value of a transformer is minimum under the condition that the power required for the load is satisfied, copper loss of a magnetic element in a circuit and conduction losses of a switch tube are reduced, meanwhile switch tubes in the circuit can achieve zero-voltage conduction within the integral transmission power range, and switch loss of a power device is effectively reduced.

Description

technical field [0001] The invention relates to a control method of an isolated bidirectional DC-DC converter, in particular to an optimal control of a bidirectional half-bridge three-level DC-DC converter. Background technique [0002] The isolated bidirectional DC-DC converter is a DC-DC converter that can operate in two quadrants and can realize electrical isolation on the input and output sides. As an important part of power electronic transformers, it is used in smart microgrids, distributed power generation systems and It is widely used in electric locomotive traction system. [0003] High-power isolated bidirectional DC-DC converters are more commonly used bidirectional full-bridge two-level circuit structure, and its topology is as follows figure 1 As shown, it consists of two symmetrical H-bridges, an intermediate frequency transformer and two DC stabilizing capacitors. The converter has a simple structure, high power density, electrical isolation and bi-direction...

AI Technical Summary

Problems solved by technology

Phase shift control is simple and easy to implement, but it does not take advantage of figure 2 At the same time, because the inductor current lags behind the voltage, it also leads to power circulation in the input and output directions within a switching cycle (such as image 3 shaded part in

When the input and output voltage amplitudes do not match, the circulating power and current stress will increase greatly, thereby increasing the loss of switching devices and magnetic components, and reducing the efficiency of the converter

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