Constant-frequency double-degree-of-freedom real-time calculation single-stage single-phase rectifier control method

Abstract

The invention relates to a constant-frequency double-degree-of-freedom real-time calculation single-stage single-phase rectifier control method, and belongs to the high-frequency power conversion direction in the field of power electronics. Constant frequency modulation is adopted, a driving signal of a power semiconductor device is obtained only through a voltage closed loop and sampling of alternating current side voltage, the primary side voltage duty ratio is 50% constantly, the secondary side voltage duty ratio and the phase shift angle are controlled to achieve unit power factor correction, and meanwhile when a primary side switch just achieves soft switching, the soft switching of all power semiconductor device can be realized in a large range, and the leakage inductance peak current of the transformer is minimum, so that the switching loss and the conduction loss can be reduced according to the boundary control just realized by the primary side soft switching. The unity power factor of the single-stage single-phase voltage source type DAB AC-DC converter is realized through full-digital control, the conversion efficiency of the converter is improved, and the converter can be applied to various industrial equipment and civil devices, such as an uninterruptible power supply, an electric vehicle charging pile and the like.

Description

technical field [0001] The invention relates to a real-time calculation single-stage single-phase rectifier control method with constant frequency and double degrees of freedom, which belongs to the direction of isolated high-frequency power conversion in the field of power electronics. Background technique [0002] Single-phase isolated rectifiers are now widely used in various industrial equipment and consumer installations, such as uninterruptible power supplies (UPS), electric vehicle charging piles, etc. The most commonly used topology is composed of two stages. The front stage is composed of a Boost circuit to achieve power factor correction, and the latter stage is composed of a high-frequency isolated DC-DC converter, such as a dual active bridge (DAB) or a resonant DC-DC. converter. The biggest advantage of the DAB topology using bidirectional switches on the AC side is that AC-DC energy conversion can be completed in a single stage, resulting in high-quality curre...

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Problems solved by technology

For example: "Switching control strategy to extend the ZVS operating range of a Dual Active Bridge AC / DC converter" published by Energy Conversion Congress and Exposition (ECCE) [Energy Conversion Conference and Expo] in 2011 [Switching control strategy extends dual active bridge AC / DC converter] / ZVS working range of DC converter], in this paper, two more effective modes are selected among the four existing modes of the DAB topology with a half-bridge structure on the AC side (transformer leakage inductance peak current and transformer leakage inductance current effective lower value) to extend the ZVS operating range of the dual active bridge AC / DC converter, but it is only a proof of concept and does not specifically consider the peak current of the transformer

[0004] In order to ensure a wide range of soft switching of the converter, suppress the peak current of the transformer, and realize voltage closed-loop and power factor correction at the same time, some scholars use the switching frequency as a new control variable for optimal control, for example: IEEETransactions on Power Electronics [IEEE Power Electronics Electronic Journal] "CombinedPhase-Shift and Frequency Modulation of a Dual-Active-Bridge AC–DC ConverterWith PFC" published in 2016 [Frequency Modulation and Phase Modulation Combined Dual Active Bridge AC–DC Converter With PFC] In the article Although it effectively suppresses the peak current of the transformer and ensures the soft switching of the converter, it is difficult to implement because of the use of look-up tables and complex formula derivation

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