A constant gain bidirectional dc-dc resonant converter and its control method

Abstract

The invention discloses a constant-gain bidirectional DC-DC resonant converter and a control method thereof. The circuit structure on both sides of the transformer of the resonant converter is completely the same, including one port, two resonant capacitors and their anti-parallel auxiliary diodes, one Resonant inductor, an auxiliary inductor and two power switch tubes. The constant-gain bidirectional DC-DC resonant converter disclosed by the invention has a symmetrical circuit structure, and the forward and reverse working performances are consistent. Under the control method designed in the present invention, the zero-voltage turn-on (ZVS) of all power switch tubes can be well realized by means of the auxiliary inductance, the circulating current loss of the converter can be reduced, and the constant voltage gain in the range from rated load to no-load can be realized at the same time , with the help of the auxiliary diode, it can play the role of overload time-limited power, and realize the natural bidirectional flow of energy in the forward and reverse operation modes, which improves the transmission efficiency and reliability of the converter.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies in the field of power electronics, and specifically relates to a constant-gain bidirectional DC-DC resonant converter, especially an LC series resonant converter, and a fixed-frequency synchronous equal-width converter for controlling the converter. Control Method. Background technique [0002] In order to alleviate the energy crisis and environmental pollution problems, the development and utilization of renewable energy have developed rapidly in recent years, such as solar energy, wind energy, tidal energy, biomass energy, etc.; however, most of the above-mentioned renewable energy such as solar photovoltaic power generation and wind power generation Energy is greatly affected by the environment and weather, and has random and intermittent characteristics. Therefore, for DC-DC converters, it needs to cope with a wide range of loads. [0003] For DC-DC converters, high transmiss...

AI Technical Summary

Problems solved by technology

The converter has relatively prominent shortcomings. First, it is uncontrollable at no-load, and second, it requires a very high switching frequency to maintain the output voltage at light load. As the switching frequency becomes higher, the circulating current of the converter increases, and the output efficiency lower

The most common control strategy is frequency conversion control, that is, the voltage gain is adjusted by controlling the switching frequency. However, for LC series resonant converters, under frequency conversion control, the forward and reverse gain characteristics are inconsistent, which is not conducive to dynamic performance; there is another commonly used The control strategy is fixed-frequency phase-shift modulation on the primary side. However, under this control strategy, the maximum equivalent gain is 1, and the large phase-shift angle will cause serious circulation loss and lower transmission efficiency.

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