Control method of LCC resonant DC-DC converter and device thereof

Abstract

The present discloses a control method of a LCC resonant DC-DC converter and a device thereof, used for controlling the LCC resonant DC-DC converter to realize zero-voltage soft switching operation in a wide input voltage range and a wide load range. According to the control method, by circuits controlling turn-on time and turn-off time of switch tubes of the LCC resonant DC-DC converter, the turn-on time and the turn-off time of the switch tubes vary with an input voltage and a load. The turn-on time and the turn-off time of the switch tubes are determined by an error value between an output voltage and a reference signal. Because a resonant current can not have an abrupt change, when any switch tube turns off, a body diode of the other switch tube immediately turns on, so that the switch tubes all work in a zero-voltage soft switching state. The control method of the LCC resonant DC-DC converter and the device thereof can reduce a switching frequency variation range of the conventional LCC resonant DC-DC converter and maintain the zero-voltage soft switching operation condition of the LCC resonant DC-DC converter in the wide input voltage range and the wide load range.

Description

Technical field [0001] The invention relates to a control method and device of an LCC resonant DC-DC converter. Background technique [0002] In recent years, power electronics technology has developed rapidly, and power technology, as an important part of the power electronics field, has gradually become a hotspot of application and research. Switching converters have established their mainstream status in the power supply field with their high efficiency and high power density. With the continuous improvement of industry requirements, switching power supplies have been developing in the direction of miniaturization, modularization and high frequency. Resonant converters have received extensive attention from industry and academia because of their good soft switching characteristics and low EMI interference. In the traditional two-element resonant converter, the series resonant converter has poor light-load voltage regulation capability, and the parallel resonant converter has ...

AI Technical Summary

Problems solved by technology

Generally, considering the complexity of the control circuit implementation, frequency conversion control is widely used in LCC resonant DC-DC converters, but the switching frequency of traditional frequency conversion control varies widely, which seriously increases the difficulty in the design of magnetic components and drive circuits in the converter; on the other hand, the use of The EMI spectrum distribution of the resonant converter controlled by frequency conversion also changes with the switching frequency when the input voltage and output power are different, which also brings difficulties to the design of various EMI filters

Although fixed frequency control eliminates the above problems by ensuring a fixed switching frequency, the soft switching range of LCC resonant DC-DC converters is severely limited and increases the voltage and current stress of each component, so it has not been widely used

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