Common Mode Voltage Reduction in Quasi-Z Source Inverter for Electric Vehicle Applications Using MBPWM Technique

Unlike traditional voltage source or current source inverters, ZSI/qZSI can boost and invert DC power in a single stage, making them attractive for applications like EVs where battery voltage may vary. Common mode Voltage (CMV) is the voltage between the neutral point of the motor and ground. High CMV in motor drive systems can cause: Higher leakage currents, Electromagnetic interference (EMI), Insulation stress, bearing currents, leading to premature motor failure. Reducing CMV is essential for reliable and safe EV operation. Pulse-width modulation (PWM) is used to control the QZSI output voltage. The QZSI offers several advantages over traditional inverters, including improved efficiency, reduced cost, and increased reliability. The proposed system is designed to reduce the CMV through a combination of passive LC filtering and shoot-through (ST) modulation techniques. The LC filter is designed to attenuate high-frequency components of the CMV while the ST modulation is used to discharge the CMV to the DC bus. MBPWM reduces the common mode voltage due to the optimized distribution of shoot through states across switching period compared to conventional SBPWM technique. So combining LC filtering with MBPWM effectively mitigate the common mode voltage in inverter fed electric drives. The performance of the proposed system is evaluated through simulations using MATLAB/Simulink. The results show that the proposed system can effectively reduce the CMV and voltage regulation of the QZSI output.