Power conversion device

Abstract

The present application provides a kind of power conversion device, can improve the degree of freedom of device selection of ZVS auxiliary circuit, shorten the reset period of resonant current in ZVS auxiliary circuit and reduce the opening loss of main switch.Electric power conversion device has: converter, including main switch element, main rectifier element, output capacitor and the primary winding of coupling inductor;Resonant auxiliary circuit based on closed loop circuit, the closed loop circuit includes the secondary winding of coupling inductor and the first series circuit of first rectifier element and auxiliary switch element, the tertiary winding of coupling inductor and the second series circuit of second rectifier element, the auxiliary capacitor connecting the first series circuit and the second series circuit, secondary winding and tertiary winding are separate, it is the structure that first series circuit and second series circuit are connected in parallel with auxiliary capacitor, or the structure that tertiary winding is integrated with secondary winding.

Claims

1. A power conversion device comprising: The converter includes a main switching element, a main rectifier element, an output capacitor, and the primary winding of a coupling inductor; and The resonant auxiliary circuit is based on a closed-loop circuit, wherein the closed-loop circuit includes a first series circuit of the secondary winding of the coupled inductor, a first rectifier element, and an auxiliary switching element; a second series circuit of the tertiary winding of the coupled inductor and the second rectifier element; and an auxiliary capacitor connecting the first series circuit and the second series circuit. The secondary winding and the tertiary winding are separate components, consisting of the first series circuit and the second series circuit connected in parallel with the auxiliary capacitor, or the tertiary winding and the secondary winding are integrated. It also has a control unit. After the control unit turns on the auxiliary switching element, it turns on the main switching element. Then, after turning off the auxiliary switching element, or simultaneously turning off the auxiliary switching element, it turns off the main switching element. The control unit uses the voltage of the auxiliary winding or the tertiary winding of the coupling inductor, where the leakage inductance ratios of the primary winding and the secondary winding are unbalanced, to determine the turn-on timing of the main switching element.

2. The power conversion device according to claim 1, wherein, It is suitable for dual boost PFCs connected to a single-phase AC input. It has two boost circuits, including the main switching element and the main rectifier element. The resonant auxiliary circuit corresponds to the two boost circuits. The auxiliary switching element is shared in the resonant auxiliary circuit.

3. The power conversion device according to claim 1, wherein, A multiphase system comprising the main switching element and the main rectifier element, The resonant auxiliary circuit is a multiphase resonant auxiliary circuit corresponding to the multiphase resonant circuit.

4. The power conversion device according to claim 3, wherein, In the multiphase resonant auxiliary circuit, one or both of the auxiliary capacitor and the second rectifier element are shared by at least two phases.

5. The power conversion device according to claim 1, wherein, The auxiliary switching element is a first auxiliary switch that is driven when the current polarity of the primary winding is positive. The auxiliary capacitor is the first auxiliary capacitor. The closed-loop circuit further includes: The third rectifier element, the second auxiliary switch driven when the current polarity of the primary winding is negative, and the third series circuit of the secondary winding; The fourth series circuit of the three-stage winding and the fourth rectifier element; and The second auxiliary capacitor is connected to the third series circuit and the fourth series circuit, and is also connected to the first auxiliary capacitor. The secondary winding and the tertiary winding are separate components, and can be either a structure in which the third series circuit and the fourth series circuit are connected in parallel with the second auxiliary capacitor, or a structure in which the tertiary winding and the secondary winding are integrated.

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