A:  1) The inverter outputs three levels for each phase, so that the line (phase) voltage has more step waves to simulate sine waves, and the output waveform distortion is reduced;
2) The output voltage change rate (du/dt) is low, and the voltage spike is low, which can reduce the damage to the motor insulation;
3) The use of three-level inverter can effectively reduce the common mode voltage at the motor end, thereby reducing the voltage end shaft voltage and shaft current, and reducing the damage to the motor bearings;
4) Low three-level harmonic content, reducing EMC costs
5) Low three-level loss at the same carrier frequency, reducing heat dissipation costs;
6) Reduce the inductance of the feedback reactor and increase the sine of the input side waveform, which is more suitable for four-quadrant applications;
7) The reverse voltage of the IGBT is half of the DC bus voltage. For example, a 1140V inverter can use a 1700V IGBT, which has high reliability