Device and method for controlling resonant bridge power converter

Abstract

The invention relates to a device for controlling a resonant bridge power converter. The signal input terminal of the device is connected with the signal output terminals of a resonance circuit and a load respectively, and the signal output terminal of the device outputs a control signal to a power switching tube; the input terminal of the power switching tube is connected with a DC (direct current) voltage source; the power switching tube, the resonance circuit and the load are connected in series; and a cycle measurement module and a timing module are arranged inside the device used for detecting the voltage and current waveform. The invention further discloses a method for controlling a resonant bridge power converter. By adding the cycle measurement module used for measuring the cycle of the change in the direction signal of the resonant current outputted by the resonance circuit and the timing module used for limiting the delay time, the invention can ensure that the limited delay time is smaller than half the oscillation period of the resonance circuit and the variable delay always ends before the direction of the resonant current is changed, thus preventing the variable delay module from repeatedly resetting.

Description

technical field [0001] The invention relates to a resonant bridge power converter, in particular to a control device and a control method for the resonant bridge power converter. technical background [0002] At present, there are many kinds of control devices for resonant bridge power converters, among which voltage-controlled oscillators and self-sustaining oscillator controllers (SSOC) are the most common. Most of the control devices of resonant bridge power converters on the market are voltage-controlled oscillators. The principle is as follows: the feedback voltage output from the optocoupler is connected to the RC oscillator of the controller, so that the oscillation frequency changes with the feedback voltage However, the upper and lower limits of frequency are set by resistors and capacitors. The disadvantage of this control method is that the values ​​of resistors and capacitors are fixed, and the output frequency range cannot adapt to the error of the frequency cha...

AI Technical Summary

Problems solved by technology

Most of the control devices of resonant bridge power converters on the market are voltage-controlled oscillators. The principle is as follows: the feedback voltage output from the optocoupler is connected to the RC oscillator of the controller, so that the oscillation frequency changes with the feedback voltage The upper and lower limits of frequency are set by resistors and capacitors. The disadvantage of this control method is that the values ​​of resistors and capacitors are fixed, and the output frequency range cannot adapt to the error of the frequency characteristics of the resonant tank.

In addition, the self-sustaining oscillation controller (SSOC) also does not have the ability to adapt to changes in the parameters of the resonant tank components. If the component error causes the resonant tank oscillation cycle to be too short, the variable delay module in the controller will be reset repeatedly before the delay is over. , repeated resets will cause the delay to never end, eventually causing the circuit to stop oscillating

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