Efficiency investigation for electric vehicle powertrain with variable DC-link bus voltage

Abstract

The electric drive powertrain is a key part of an electric vehicle (EV). The performance and efficiency of an EV largely depend on its powertrain. In this paper, two induction motor based powertrains, one with constant and other having variable DC-link bus voltage (Vdc) are investigated from efficiency viewpoint. The variable Vdc is achieved using a DC-DC converter between inverter and input DC source. A technique to calculate the required Vdc for different operating condition of powertrain is also proposed. Both the powertrains are operated for wide speed and torque ranges. Efficiency maps for different parts of powertrains and complete system are presented for both the cases. It is experimentally observed that powertrain configuration with variable Vdc operates at higher efficiency in comparison to powertrain with constant Vdc.