Investigation of electromagnetic torque production in induction motor during charging operation

Integrated battery chargers (IBCs) provide the flexibility of reusing the electric drive-train components of the electric vehicle (EV) for the charging operation. The purpose of the paper is to reuse its traction inverter and motor windings as rectifier and grid interfacing filter, respectively for charging and keeping rotor standstill without using any external brake. Various winding configurations are developed by splitting the three-phase induction motor (IM) winding into two parts at zero electrical degree to keep the rotor standstill. The different stator winding connections are proposed for IM which restricts the formation of rotating magnetic field (RMF). Cases are categorized into two parts, in the first part, RMF is cancelled to zero and in the other part, RMF is converted into pulsating magnetic field (PMF). Mathematical investigation for torque production in both cases is provided to prove that the proposed winding connections are incapable of developing electromagnetic torque in machine. Mathematical findings are validated by experimentation on split three-phase IM (STP-IM). This analysis is useful in identifying the nature of torque developed in motor during charging operation of EV.