Robust and efficient torque control of permanent magnet synchronous motors in traction applications

A control scheme is presented for the robust performance of permanent magnet synchronous motor drives in the presence of voltage and current constraints. Strategies like Maximum Torque per Ampere (MTPA) are straightforward to implement and the approach is well suited for field-weakening and full voltage utilization of the inverter. In combination with fast torque control, these properties make the scheme ideal for traction applications, where weight and size constraints require a minimal inverter. The approach has been evaluated on trains in passenger service. These tests have shown that stability and performance are maintained over the entire range of operating conditions.