A bidirectional dc-dc soft switching circuit and wide range soft switching control method

Abstract

The invention discloses a bidirectional DC-DC soft switch circuit and a wide range soft switch control method, comprising: a main inductance L, a first resonant inductance L r1 , the second resonant inductance L r2 , power switch tube S 1 ~S 4 , Diode D 1 ~D 4 , the first resonant capacitor C r1 , the second resonant capacitor C r2 ; One end of the main inductance L is simultaneously connected with the first resonant inductance L r1 One end of the second resonant inductance L r2 One end of the first resonant capacitor C r1 One end of the second resonant capacitor C r2 One end of the power switch tube S 1 The second terminal and the power switch S 2 The first end of the main inductance L is connected; the other end of the main inductor L is connected to the low-voltage side power supply V L or load R L The positive phase of the connection; the first resonant inductance L r1 The other end of the power switch tube S respectively 3 of the second terminal and the diode D 1 The cathode is connected; the soft switching function in the Buck / Boost bidirectional mode is realized, which broadens the soft switching realization range of the proposed bidirectional DC-DC soft switching circuit, and is suitable for applications with wide input or wide output.

Description

technical field [0001] The invention belongs to the technical field of DC-DC converters, in particular to a bidirectional DC-DC soft switch circuit and a wide-range soft switch control method. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] In recent years, with the development of new energy power generation, electric vehicles and energy storage systems, bidirectional DC-DC converters have received extensive attention and research. [0004] In the prior art, the traditional bidirectional DC-DC converter topology such as figure 1 As shown, the switching tube will produce certain switching loss and electromagnetic interference during the turn-on or turn-off process. When the switching frequency of the converter is low, its switching loss is relatively small; at present, the converter is developing towards miniaturization and light weight,...

AI Technical Summary

Problems solved by technology

[0005] The inventor found in the research that the current DC-DC soft switching schemes include quasi-resonant circuits, zero-switching PWM circuits, zero-switching PWM circuits, etc., most of which are improved Boost converters or Buck converters, and the energy can only be Direct flow, not suitable for electric vehicles, energy storage systems and other occasions that require two-way flow of energy

At the same time, there are many zero-voltage conversion PWM soft switching circuits currently used. The control method is mainly that the auxiliary switch is turned on for a short period of time before the main switch is turned on. However, this method is applied to wide input or wide output occasions, That is, when the duty cycle varies widely, the resonant inductance on the branch of the auxiliary switching tube may not be able to obtain enough energy to make the resonant circuit work normally, thus affecting the realization effect of soft switching

[0006] To sum up, in the prior art, there is still no effective solution to the problem that the bidirectional DC-DC converter needs a sufficiently high switching frequency and a wide range of soft switching.

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