Isolation type high-frequency low-loss driving circuit

Abstract

The invention relates to a power electronics and electric energy conversion circuit, and aims to provide an isolation type high-frequency low-loss driving circuit. The isolation type high-frequency low-loss driving circuit comprises MOSFETs which are simplified to be switching tubes M; each driving circuit also comprises a square wave power supply, a resonant inductor, a primary winding and a first secondary winding, wherein the square wave power supply, the resonant inductor and the primary winding are connected in series; one end of the first secondary winding is connected to the gate pole of each switching tube M while the source electrode of the switching tube M is connected to the other end of the first secondary winding; and the primary winding and the first secondary winding are wound around the same magnetic core to form a transformer T1. According to the isolation type high-frequency low-loss driving circuit, capacitance resonance is input through the resonant inductor and the gate pole of the switching tube, so that the voltage on parasitical capacitor is sine waveform, and therefore, the driving of the switching tube is realized, and recycling of driving energy is also achieved, thereby reducing driving loss; in addition, the gate pole voltage can be clamped through a clamping winding, so that damage to the switching tube caused by an overhigh gate pole voltage can be prevented; and by adopting a way of increasing the secondary windings, driving of multiple switching tubes can be realized.

Description

technical field [0001] The invention relates to a class of power electronic electric energy conversion circuits, in particular to a class of isolated drive circuits. Background technique [0002] With the development of power electronics technology, the power density of power converters has been continuously improved, and its operating frequency has reached the MHz level. Although a higher operating frequency can reduce the volume of the energy storage element and increase the power density of the power converter, the driving loss of the MOSFET will also increase. The traditional DC / DC converter MOSFET drive circuit generally adopts such as figure 1 The structure shown is to realize: the switching tubes S1 and S2 constitute a bridge arm, Rg is the gate equivalent resistance, Cgs is the equivalent capacitance between the gate and the source, and Q is the driven switching tube. The shortcomings of this structure are: because the power electronic device is not an ideal switch...

AI Technical Summary

Problems solved by technology

The shortcomings of this structure are: because the power electronic device is not an ideal switch, there is an overlap time between the voltage at both ends of the switch tubes S1 and S2 and the current flowing through the switch tubes, resulting in serious switching losses; and the process of driving the switch tube Q is During the charging and discharging process of the equivalent capacitance Cgs, during the charging and discharging process of Cgs, the current flows through the gate equivalent resistance Rg, resulting in loss. This part of the loss increases with the increase of the switching frequency, and it will be serious at the frequency of MHz level. affect the efficiency of the circuit

The disadvantage of this structure is that it is difficult to control the gate voltage amplitude of the switching tube M

The disadvantage of this structure is: the switching tube works in the hard switching state

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