Soft Switching Auxiliary Circuit, Three-Level Three-Phase Zero-Voltage Conversion Circuit

A soft switching auxiliary circuit, characterized in that:

• the soft switching auxiliary circuit is connected in parallel with a main switch transistor of a main circuit, and the soft switching auxiliary circuit comprises an auxiliary coupling inductor, a clamping diode and an auxiliary switch transistor, wherein the auxiliary coupling inductor has an input connected with a respective branch of the main circuit and an output connected with the clamping diode, the clamping diode is connected with one terminal of the main switch transistor, another terminal of the main switch transistor is connected with the auxiliary switch transistor, and the auxiliary switch transistor is connected with the clamping diode.

A three-level three-phase zero-voltage conversion circuit, characterized by comprising:

• a three-level three-phase main circuit and two auxiliary circuits, wherein upper arms of three branches of the three-level three-phase main circuit are respectively connected with one auxiliary circuit to constitute an upper soft switching circuit, and lower arms of the three branches of the three-level three-phase main circuit are respectively connected with the other auxiliary circuit to constitute a lower soft switching circuit, the two auxiliary circuits being connected with each other, wherein each of the two auxiliary circuits comprises an auxiliary coupling inductor, a clamping diode and an auxiliary switch transistor, wherein the auxiliary coupling inductor has an input connected with a respective branch of the main circuit and an output connected with the clamping diode, one terminal of the main switch transistor is connected with the auxiliary switch transistor, and the auxiliary switch transistor is connected with the clamping diode, and wherein the clamping diodes of the two auxiliary circuits are connected with each other.

A three-level three-phase zero-voltage conversion circuit, characterized by comprising:

• a three-level three-phase main circuit and two auxiliary circuits, wherein upper arms of three branches of the three-level three-phase main circuit are respectively connected with one auxiliary circuit to constitute an upper soft switching circuit, and lower arms of the three branches of the three-level three-phase main circuit are respectively connected with the other auxiliary circuit to constitute a lower soft switching circuit, the two auxiliary circuits being connected with each other, wherein each of the two auxiliary circuits comprises an auxiliary coupling inductor, a clamping diode and an auxiliary switch transistor, wherein the auxiliary coupling inductor has an input connected with a respective branch of the main circuit and an output connected with the clamping diode, the clamping diode is connected with one terminal of the main switch transistor, another terminal of the main switch transistor is connected with the auxiliary switch transistor, and the auxiliary switch transistor is connected with the clamping diode, and wherein the clamping diodes of the two auxiliary circuits are connected with each other.