PWM plus dual phase-shifting control method for bidirectional DC/DC convertor

Abstract

The invention discloses a PWM plus dual phase-shifting control method for a bidirectional DC / DC convertor. The method includes the steps of collecting the port voltage of the bidirectional DC / DC convertor in real time, and computing the duty ratio of a control signal when rematch of the leakage inductance voltage is conducted; acquiring the outward phase-shift angle j output by a circuit closed-loop controller; computing the inward phase-shift angle j0 acted on a second bridge arm of a modified H bridge when circuit power circulation is eliminated totally according to the obtained duty ratio and the outward phase-shift angle; generating the parameters of the outward phase-shift angle, the duty ratio and the inward phase-shift angle into a control signal of the circuit. The PWM plus dual phase-shifting control method for the bidirectional DC / DC convertor has the advantages of being suitable for the convertor with the bi-directional DC / DC topological structure, wherein one side of the convertor is the modified H bridge, the other side of the convertor is buck, boost or other derived circuits, reducing the current stress of a circuit switch device, expanding the soft switching range of the circuit, completely eliminating the circulation power in the circuit when the circuit works under different working conditions of light or heavy load, and improving work efficiency of the circuit.

Description

technical field [0001] The invention relates to a PWM plus double phase shifting control method for a bidirectional DC / DC converter. Background technique [0002] Bidirectional DC / DC is applied in many occasions that require bidirectional transmission of power. Phase shift control technology is applied to bidirectional DC / DC converters, which can conveniently manage bidirectional transmission of energy, and is easy to realize soft switching of power devices. There are certain defects in the traditional phase-shift control technology. For example, when the converter works under the condition that the port voltage does not match, the current stress of the circuit switch increases, the range of soft switching becomes smaller, and the internal circulating power of the converter increases, which brings more Much loss. [0003] At present, some related control methods have been proposed for the problem of port voltage mismatch, such as: [0004] (1) For the bidirectional DC / DC t...

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Problems solved by technology

[0005] (2) in such as figure 2 On the basis of the shown dual-active full bridge, the control strategy of external phase shift and internal phase shift is adopted on the primary side and the secondary side H-bridge at the same time. This method can eliminate the power circulation flowing in the dual-active full bridge. Active full bridge topology, small application range

[0006] (3) Based on the dual-active full-bridge, the dual-phase-shift control method is implemented on the H-bridge on the side of the dual-active full-bridge. This method can also eliminate the power circulation in the circuit. Its working waveform is as follows: image 3 ; But only when the converter is working under heavy load, that is, when the external phase angle is large, the circulating current power of the circuit can be eliminated by setting a suitable internal phase shifting angle, and the circulating current cannot be completely eliminated in the entire phase shifting range. However, when the converter works at light load, it is in a state of relatively low working efficiency. This method does not improve the working state of the circuit at light load.

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