Hybrid Output Voltage Modulation (PWM-FSHE) for a Modular Battery System Based on a Cascaded H-Bridge Inverter for Electric Vehicles Reducing Drivetrain Losses and Current Ripple

This paper shows a preliminary study about the output voltage modulation of modular battery system based on seven-level cascaded H-bridge inverter used for vehicle propulsion. Two generally known techniques, pulse width (PWM) and fundamental selective harmonic elimination (FSHE), are extensively compared such an innovative considering EVs’ broad torque-speed range. The losses, as well inverter-induced current THD, modeled quantified using simulations. At low speeds, if index M is below 0.3, FSHE induces high THD (>>5%) and, thus, cannot be used. medium reduces drivetrain losses (including losses), while operating at higher it even THD. Thus, individual boundary between multilevel PWM can determined weightings efficiency quality. Based this, simple hybrid technique suggested inverters, improving simulated drive cycle by maximum 0.29% to 0.42% small passenger vehicle. Furthermore, FSHE’s speed dominance demonstrated experimental setup with inductive load.