Common Mode Voltage Reduction Method for H7 Inverter Using DPWM Offset Based Modulation Technique

In this paper, a common mode voltage (CMV) reduction method for the three-phase two-level inverter using the H7 inverter and DPWM-based advanced modulation techniques is proposed. The conventional CMV reduction method using the H7 inverter requires an additional logic circuit for implementing a modified DPWM (MDPWM), and there is the problem that the CMV is not reduced in some areas. The proposed method generates the DPWM switching signals for the three-phase inverter using the modulation method of the offset voltage. The minimum value of the pole voltage reference V
_min
* is detected and compared with the triangular wave to produce the switching signal of the S7 switch. The proposed method implement switching signals of all the switches using only one carrier without additional logic circuit, and reduced the common mode voltage in all sectors. Simulation results are provided to show the performance of proposed method in CMV.