Optimal Sizing of Hairpin Conductors in highway operation with PWM power supply

Nowadays, one of the key challenges in the design of electric drives’ components is the reduction of high losses at high-frequency operations. The aim of this work is to investigate the AC losses in hairpin windings (HWs) triggered by a space vector pulse width modulation (SVPWM) during both maximum torque per Ampère (MTPA) and flux-weakening (F-W) operations of an interior permanent magnet synchronous motor (PMSM). The ensuing additional losses are evaluated and a fast methodology for the conductor sizing is illustrated. Subsequently, after evaluating the harmonic content of the current feeding the electric motor, estimated considering a standardized highway driving cycle, the losses are assessed using analytical and finite element methods (FEM) and then compared with an HW layout taken as benchmark. The results demonstrate that HWs, when appropriately sized, can significantly reduce AC losses compared to conductors optimised for low-speed extra-urban conditions.