Multiple-resonant soft switch converter

Abstract

The invention discloses a multi-resonance soft-switch converter which comprises a symmetric square wave pulse generating circuit, a resonance circuit and a transformer T1 and is characterized in that the resonance circuit comprises a resonant inductor L1, a resonant capacitor C1, an excitation inductor Lm, an auxiliary inductor L2 and an auxiliary capacitor C2. The beneficial effects of the converter are that: 1. as an auxiliary unit is added, the impedance of a resonant unit is changed rapidly until infinitely great around the resonant frequency of the auxiliary unit, thus realizing gain regulating and providing a possibility for the realization of wide voltage range application; 2. the work frequency range is reduced and the control protection and efficiency optimizing can be easily realized; 3. viewing from a gain curve, higher harmonic (such as third harmonic) can be introduced by appropriate parameter design for causing current wave pattern to be closer to the square wave so as to reduce the effective value of the current and enhance the efficiency.

Description

technical field [0001] The invention relates to a multi-resonant converter circuit. More precisely, the present invention relates to a five-element current resonance type soft switching converter. Background technique [0002] In the traditional PWM chopper converter, its power components work in the hard switching mode, the switching loss is large, the efficiency is low, it is difficult to increase the power density through high frequency, and the EMI characteristics are poor, so many filter suppression units need to be added. It not only increases the cost, but also reduces the efficiency. [0003] The resonant converter uses a resonant circuit to create soft switching conditions for power components and reduce switching losses. In the resonant converter, a three-element LLC current resonant converter (see figure 1 ) is the most typical and widely used. [0004] Compared with other soft-switching converters, the LLC converter can realize the zero-voltage turn-on of the...

AI Technical Summary

Problems solved by technology

[0005] Disadvantages of the LLC converter: Since the LLC works best only near the resonant frequency, the rated operating point is often set near the resonant frequency. When the input voltage decreases or the output voltage increases, the operating frequency is lowered to obtain a greater gain; when the input voltage increases or the output voltage decreases, a lower gain is obtained by increasing the operating frequency

This largely limits the application of LLC soft-switching converters

In many applications that require a wide voltage range, the existing LLC converter is difficult to obtain a better application

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