Three-phase resonant converter and method of controlling the same

A three-phase resonant converter, comprising:

• a three-phase transformer comprising three primary-side windings and three secondary-side windings;
• an input bridge arm assembly comprising a first input switch arm, a second input switch arm, and a third input switch arm respectively coupled to the three primary-side windings, each input switch arm comprising an upper switch and a lower switch;
• an output bridge arm assembly comprising a first output synchronous rectification switch arm, a second output synchronous rectification switch arm, and a third output synchronous rectification switch arm respectively coupled to the three secondary-side windings, each output synchronous rectification switch arm comprising an upper rectification switch and a lower rectification switch;
• a control unit configured to generate switching signals to control the input bridge arm assembly and the output bridge arm assembly;
• and
• a current balance controller coupled to the control unit and configured to:
• receive a first current, a second current, and a third current respectively corresponding to currents flowing from respective nodes between the upper switches and the lower switches of the first, second, and third input switch arms toward the three-phase transformer;
• determine a first phase angle difference and a second phase angle difference based on the first current, the second current, and the third current;
• and
• provide the first phase angle difference and the second phase angle difference to the control unit,
• wherein the current balance controller determines the first phase angle difference and the second phase angle difference based on at least one of a peak value, an average value, or a root-mean-square value of each of the first current, the second current, and the third current,
• wherein the control unit controls the first, second, and third output synchronous rectification switch arms such that:
• turn-on timing of the upper rectification switch and the lower rectification switch of the first output synchronous rectification switch arm is controlled according to a first phase angle;
• turn-on timing of the upper rectification switch and the lower rectification switch of the second output synchronous rectification switch arm is controlled according to a second phase angle equal to the first phase angle plus the first phase angle difference;
• and
• turn-on timing of the upper rectification switch and the lower rectification switch of the third output synchronous rectification switch arm is controlled according to a third phase angle equal to the first phase angle plus the second phase angle difference.