A high-gain bidirectional three-phase dc-dc converter and its control method

Abstract

The invention discloses a high-gain bidirectional three-phase DC-DC converter and a control method, and belongs to the bidirectional high-frequency power conversion direction in the field of power electronics. A main circuit of the high-gain bidirectional three-phase DC-DC converter is mainly composed of three inductors L1 to L3, six power switch tubes S1 to S6, and four capacitors Cf, CL, CH1 andCH2, wherein the first inductor L1 is respectively connected with the power switch tube S1 and the power switch tube S4, the second inductor L2 is connected with the power switch tube S2 and the second capacitor Cf, and the third inductor L3 is connected with the power switch tube S3, the third capacitor CH1 and the fourth capacitor CH2. According to the control method, a 180-degree staggered control mode can increase the duty ratio range to the maximum extent and reduce total voltage ripples of the high-voltage side; the 120-degree staggered control mode can reduce the total current ripplesof the low-voltage side to the maximum extent. The high-gain bidirectional three-phase DC-DC converter has a higher voltage conversion ratio, the power switch tube has lower voltage stress. Moreover,the two high-voltage side capacitors CH1 and CH2 can realize automatic voltage stabilization, and the three filter inductors realize automatic current sharing.

Description

technical field [0001] The invention relates to the technical field of DC-DC converters, in particular to a high-gain bidirectional three-phase DC-DC converter 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 three-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, the voltage conversion ratio of the above-mentioned traditional bidirectional three-phase DC-DC converter is limited, and it is difficult to increase the voltage conversion ratio to 4 times above. Therefore, when a sufficiently large voltage conversion ratio needs to be obtai...

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 that the DC-DC converter cannot meet the requirement of obtaining a sufficiently large voltage conversion ratio.

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