4-Level GaN Inverter and Motor HF-Loss Models for EVs
Improving electric drive-train efficiency directly enhances the range of electric vehicles. This project focuses on boosting efficiency through system-level optimisation of four-level GaN inverters and electric machines.
The adoption of electric vehicles is gaining momentum due to growing concerns over climate change and advancements in battery technology. However, mass adoption is facing challenges due to inadequate but increasing charging infrastructure and range limitation. By increasing the efficiency of electric drive-train, the range of the electric vehicle can be increased.
At HPE, concepts to increase the efficiency of electric drive-train and address range limitation are investigated. The project is part of the EU-ENLIGHTEN project, to design and develop next generation 1200V drive inverter. With a system voltage of 1200 V, utilizing GaN devices rated for 650 V, four-level inverter topologies are investigated to increase the number of voltage levels and reduce harmonic distortion of phase currents. GaN devices enable higher switching frequency operation, improving the phase current ripple, and increases the power density of the inverter due to reducing size of passive and filter components.
In the project, optimised PWM modulation schemes and four-level inverter
topologies are studied and developed. Together with high-fidelity winding and iron loss models of electric machines, these are employed to perform
comprehensive system-level optimisations. The optimisations focus on minimising system (inverter and motor) losses in low current/torque region, as most of the energy in a typical drive cycle is consumed within this operating range.