A kind of pwm plus double phase shifting control method for bidirectional dc/dc converter

Abstract

The invention discloses a PWM plus double phase shift control method for a bidirectional DC / DC converter, comprising: collecting the port voltage of the bidirectional DC / DC in real time, and calculating the duty ratio of the control signal when the leakage inductance voltage is re-matched ; Obtain the external phase angle j output by the closed-loop controller of the circuit; calculate the internal phase angle acting on the second bridge arm of the improved H bridge when the circuit power circulation is completely eliminated according to the obtained duty cycle and the external phase angle j 0 ; The three parameters of external phase angle, duty cycle and internal phase angle are used to generate the control signal of the circuit. The beneficial effects of the present invention are: the present invention is applicable to a bidirectional DC / DC topology structure in which one side of the converter is an improved H-bridge, and the other side is a buck, boost or its derivative circuit, which can reduce the current stress of the circuit switching device , expand the soft switching range of the circuit, and can completely eliminate the circulating power in the circuit when the circuit works in different working conditions such as light load or heavy load, and improve the working 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...

AI Technical Summary

Problems solved by technology

[0004] (1) For the bidirectional DC / DC topology shown in Figure 1(a), the control strategy of PWM plus traditional phase shifting is adopted. This strategy realizes the voltage at both ends of the transformer leakage inductance Active matching improves the working condition of the bidirectional DC / DC converter to a certain extent. circulation problem

[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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