Shaping Induction Machine Rotor Slots for Driving Cycle Loss Reduction

This paper develops an induction machine design methodology to reduce energy consumption during a city driving cycle using steady-state optimal flux. Conventional induction machine design has focused on maximizing steady-state efficiency. Driving cycle loss evaluation using proper control has not been well addressed considering transients. In this paper, the total energy consumption during transients is separated into the accumulated steady-state energy consumption and the energy consumption for rotor flux state (RFS) transients. Parametric analysis of transient and steady-state losses is conducted using a lumped parameter model. An operating point dependent analytical model is developed to achieve desired the torque and stator flux control and is verified by finite element analysis (FEA). Geometric design tradeoffs for the total driving cycle losses, accumulated steady-state losses and increased energy consumption for RFS transients are presented for four key design variables. Design optimization for driving cycle loss reduction is conducted in a full design space.