Solid-state switch device and operating method for the same

A solid-state switch device connected between a three-phase power supply source and a load, comprising:

• a first phase bridge arm circuit, including a first power semiconductor switch and a second power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the first power semiconductor switch and the second power semiconductor switch are connected in series in a first phase of the three-phase power supply source;
• a second phase bridge arm circuit, including a third power semiconductor switch and a fourth power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the third power semiconductor switch and the fourth power semiconductor switch are connected in series in a second phase of the three-phase power supply source;
• a third phase bridge arm circuit, including a fifth power semiconductor switch and a sixth power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the fifth power semiconductor switch and the sixth power semiconductor switch are connected in series in a third phase of the three-phase power supply source;
• a phase voltage sampling circuit, configured to acquire sampled values of first phase voltage of the first phase bridge arm circuit, sampled values of second phase voltage of the second phase bridge arm circuit and sampled values of third phase voltage of the third phase bridge arm circuit;
• and
• a control circuit, configured to performs the following operations:
• determining direction of a line voltage between the first phase bridge arm circuit and the second phase bridge arm circuit according to the sampled values of the first phase voltage and the sampled values of the second phase voltage, and turning on one of the power semiconductor switches in the first phase bridge arm circuit whose body diode's direction is the same as the direction of the line voltage and one of the power semiconductor switches in the second phase bridge arm circuit whose body diode's direction is the same as the direction of the line voltage;
• turning on the other of the power semiconductor switches in the first phase bridge arm circuit and the other of the power semiconductor switches in the second phase bridge arm circuit within a half cycle after the immediate zero-crossing of the line voltage, and determining, after the immediate zero-crossing of the line voltage, direction of a voltage across the third phase bridge arm circuit according to the sampled values of the first phase voltage, the sampled values of the second phase voltage and the sampled values of the third phase voltage, and turning on one of the power semiconductor switches in the third phase bridge arm circuit whose body diode's direction is the same as the direction of the voltage;
• and
• turning on the other of the power semiconductor switches in the third phase bridge arm circuit within a half cycle after the immediate zero-crossing of the voltage across the third phase bridge arm circuit,
• wherein the first phase bridge arm circuit, the second phase bridge arm circuit and the third phase bridge arm circuit are connected in a star connection.

An operating method for a solid-state switch device connected between a three-phase power supply source and a load, wherein the solid-state switch device includes a first phase bridge arm circuit, a second phase bridge arm circuit and a third phase bridge arm circuit which are connected in a star connection, the first phase bridge arm circuit includes a first power semiconductor switch and a second power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the first power semiconductor switch and the second power semiconductor switch are connected in series in a first phase of the three-phase power supply source, the second phase bridge arm circuit includes a third power semiconductor switch and a fourth power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the third power semiconductor switch and the fourth power semiconductor switch are connected in series in a second phase of the three-phase power supply source, and the third phase bridge arm circuit includes a fifth power semiconductor switch and a sixth power semiconductor switch, which each includes a first end, a second end and a control end and each includes a body diode, wherein the second ends of the fifth power semiconductor switch and the sixth power semiconductor switch are connected in series in a third phase of the three-phase power supply source, the operating method comprising:

• acquiring sampled values of first phase voltage of the first phase bridge arm circuit, sampled values of second phase voltage of the second phase bridge arm circuit and sampled values of third phase voltage of the third phase bridge arm circuit;
• determining direction of a line voltage between the first phase bridge arm circuit and the second phase bridge arm circuit according to the sampled values of the first phase voltage and the sampled values of the second phase voltage, and turning on one of the power semiconductor switches in the first phase bridge arm circuit whose body diode's direction is the same as the direction of the line voltage and one of the power semiconductor switches in the second phase bridge arm circuit whose body diode's direction is the same as the direction of the line voltage;
• turning on the other of the power semiconductor switches in the first phase bridge arm circuit and the other of the power semiconductor switches in the second phase bridge arm circuit within a half cycle after the immediate zero-crossing of the line voltage, and determining, after the immediate zero-crossing of the line voltage, direction of a voltage across the third phase bridge arm circuit according to the sampled values of the first phase voltage, the sampled values of the second phase voltage and the sampled values of the third phase voltage, and turning on one of the power semiconductor switches in the third phase bridge arm circuit whose body diode's direction is the same as the direction of the voltage;
• and
• turning on the other of the power semiconductor switches in the third phase bridge arm circuit within a half cycle after the immediate zero-crossing of the voltage across of the third phase bridge arm circuit.