A high-gain bidirectional four-phase dc-dc converter based on coupled inductors and its control method

Abstract

The invention discloses a high-gain bidirectional four-phase DC-DC converter based on a coupling inductor and a control method. The converter comprises the four-phase coupling inductor, eight power switch tubes S1 to S8 and five capacitors CL, C1, C2, CH1 and CH2, wherein the inductance of all phases of the coupling inductor includes inductance L1 to L4, the coupling mode is a positive-negative coupling mode, and that is to say, positive coupling is realized between odd-number phases and between even-number phases of the coupling inductor and negative coupling is realized between the odd-number phases and the even-number phases. The converter has a higher voltage conversion ratio, and the voltage conversion ratio of the converter can be increased to be four times that of a traditional bidirectional four-phase DC-DC converter; the power switch tubes have lower voltage stress, the voltage borne when the power switch tubes S2, S4 and S6 are turned off is one half of the high-voltage sidevoltage, and the voltage borne when the power switch tubes S1, S3, S5, S7 and S8 is one fourth of the high-voltage side voltage.

Description

technical field [0001] The invention relates to the technical field of DC-DC converters, in particular to a high-gain bidirectional four-phase DC-DC converter based on coupled inductance and a control method. Background technique [0002] In recent years, with the development of new energy power generation, electric vehicles and energy storage systems, bidirectional high-gain DC-DC converters have received extensive attention and research. [0003] In the prior art, the traditional bidirectional four-phase DC-DC converter circuit topology such as figure 1 As mentioned above, due to the influence of parasitic parameters in the circuit, especially the influence of the equivalent internal resistance of the inductor and capacitor, it is difficult for the above-mentioned traditional bidirectional four-phase DC-DC converter to obtain a larger voltage conversion ratio. Therefore, when a sufficiently large voltage conversion ratio needs to be obtained, the above-mentioned circuit w...

AI Technical Summary

Problems solved by technology

[0005] The first is to use a transformer to realize buck-boost, and its energy conversion link is DC-AC-AC-DC. However, due to the large number of conversion links in this solution, the energy conversion efficiency becomes low.

[0006] The second is to use switched capacitor technology to achieve buck-boost, but this solution requires too many switching devices, which increases the cost and complicates the control

[0007] The third is to use coupled inductor technology to achieve buck-boost, but the leakage inductance of the coupled inductor will cause excessive voltage spikes and increase losses

[0008] To sum up, in the prior art, there is still no effective solution to the problem of how to obtain a sufficiently large voltage conversion ratio under the premise of requiring as few components as possible for the DC-DC converter.

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