Zero-current detection system for series resonance power supply

The invention discloses a zero-current detection system for a series resonance power supply and belongs to the technical field of power electronics. The system comprises a current sampling circuit, a reference voltage source, a voltage comparator and a turn-off pulse forming circuit, wherein the current sampling circuit is connected to the inverse switch direct-current bus input end of the series resonance power supply, a current sensor T1 and a backward diode V1 are arranged in the current sampling circuit, the output end of the current sensor T1 is connected with the backward diode V1 in parallel, a negative pole of the backward diode V1 and the reference voltage source are connected to the input end of the voltage comparator, and the output end of the voltage comparator is connected with the turn-off pulse forming circuit. The zero-current detection system for the series resonance power supply solves the problems that voltage drop of a rectifier diode results in distortion, a second zero crossing point needs processing and the circuit is complicated in the prior art, and has the advantages that the circuit is simple and the zero-current detection function can be realized without utilization of rectification devices.