High-frequency isolation alternating/direct current conversion circuit and control method thereof

A high-frequency isolation alternating/direct current conversion circuit, comprising:

• a single-phase alternating current source, a direct current source, a first capacitor, a second capacitor, a third capacitor, a high-voltage energy-storage filter, a first high-frequency full-bridge inverter circuit, a second high-frequency full-bridge inverter circuit, a third high-frequency full-bridge inverter circuit, a drive circuit, a first inductor, a second inductor, a high-frequency isolation transformer, and a control circuit connected to the drive circuit, wherein the first capacitor is connected in parallel to the single-phase alternating current source, the second capacitor is connected in parallel to the direct current source, and the first high-frequency full-bridge inverter circuit, the second high-frequency full-bridge inverter circuit and the third high-frequency full-bridge inverter circuit are each composed of a switch tube;
• in the first high-frequency full-bridge inverter circuit, a first alternating current end and a second alternating current end are respectively connected to a second end of the first inductor and a second end of the first capacitor, a first direct current end and a second direct current end are respectively connected to a positive pole and a negative pole of the high-voltage energy-storage filter, and a first end of the first inductor is connected to a first end of the first capacitor;
• in the second high-frequency full-bridge inverter circuit, a first alternating current end is connected to a first end of the high-frequency isolation transformer at a single-phase alternating current source side by means of the second inductor, a second alternating current end is connected to a second end of the high-frequency isolation transformer at the single-phase alternating current source side by means of the third capacitor, and a first direct current end and a second direct current end are respectively connected to the positive pole and the negative pole of the high-voltage energy-storage filter;
• and
• in the third high-frequency full-bridge inverter circuit, a first direct current end and a second direct current end are respectively connected to a positive pole and a negative pole of the direct current source, and a first alternating current end and a second alternating current end are respectively connected to a first end and a second end of the high-frequency isolation transformer at the direct current source side.

A high-frequency isolation alternating/direct current conversion circuit, comprising:

• a three-phase alternating current source, a direct current source, a high-voltage energy-storage filter, a first high-frequency full-bridge inverter circuit, a second high-frequency full-bridge inverter circuit, a third high-frequency full-bridge inverter circuit, a drive circuit, a resonant inductor, a resonant capacitor, a filter capacitor at a direct current side, a high-frequency isolation transformer, and a control circuit connected to the drive circuit, wherein the three-phase alternating current source is coupled to an alternating current end of the first high-frequency full-bridge inverter circuit, a first direct current end and a second direct current end of the first high-frequency full-bridge inverter circuit are respectively connected to a positive pole and a negative pole of the high-voltage energy-storage filter, and an LC filter is connected between the three-phase alternating current source and the alternating current end of the first high-frequency full-bridge inverter circuit;
• in the second high-frequency full-bridge inverter circuit, a first alternating current end is connected to a first end of the high-frequency isolation transformer at a three-phase alternating current source side by means of the resonant inductor, a second alternating current end is connected to a second end of the high-frequency isolation transformer at the three-phase alternating current source side by means of the resonant capacitor, and a first direct current end and a second direct current end are respectively connected to the positive pole and the negative pole of the high-voltage energy-storage filter;
• and
• in the third high-frequency full-bridge inverter circuit, a first direct current end and a second direct current end are respectively connected to a positive pole and a negative pole of the direct current source, and a first alternating current end and a second alternating current end are respectively connected to a first end and a second end of the high-frequency isolation transformer at the direct current source side.