Resonant circuit and control method thereof

A parallel resonant circuit, comprising N(N≥2) resonant circuits connected in parallel, each of the N resonant circuits comprising power switches and a rectifier bridge, and each of the N resonant circuits further comprising:

• a sampling unit, configured to sample an output currents and an output voltage of the rectifier bridges of a corresponding resonant circuit to obtain an output current signal and an output voltage signals;
• an average value calculating unit, configured to calculate an average output current based on N output current signals;
• a voltage loop controller, configured to adjust an output voltage of the corresponding resonant circuit based on a reference voltage value;
• generate a first current difference by comparing an output current of the corresponding resonant circuit with the average output current;
• correct the reference voltage value based on the first current difference to generate a final reference voltage value;
• generate an output voltage difference by comparing the final reference voltage value and the output voltage of the corresponding resonant circuit;
• and generate a first control voltage signal based on the output voltage difference;
• a current loop controller, configured to generate a second current difference by comparing a first current threshold and the output current of the corresponding resonant circuit;
• and generate a second control voltage signal based on the second current difference;
• a selection unit, configured to receive the first control voltage signal and the second control voltage signal;
• selectively output the first control voltage signal or the second control voltage signal to the corresponding resonant circuit based on a comparison between the first current threshold and the output current of the corresponding resonant circuit;
• adjust a switching frequency of the corresponding resonant circuit based on the first control voltage signal or the second control voltage signal, thereby achieving current-sharing or current-limiting control of the corresponding resonant circuit;
• wherein when the output current of the corresponding resonant circuit is less than the first current threshold, the selection unit selectively outputs the first control voltage signal to control the corresponding resonant circuit to operate in a current-sharing mode;
• and
• when the output current of the corresponding resonant circuit is greater than or equal to the first current threshold, the selection unit selectively outputs the second control voltage signal to control the corresponding resonant circuit to operate in a current-limiting mode.