An integrated on-board battery charger with a nine-phase PM machine

Abstract

Abstract-A fully integrated on-board battery charger for electrical vehicles (EVs) has been developed recently using a nine-phase machine. All the components used for propulsion are employed in the charging process, no additional components are required, and there is no need for hardware reconfiguration between charging and propulsion modes of operation. The proposed solution can be connected directly to single-phase or three-phase grid to perform charging, so that the expensive offboard charger infrastructure is not needed. The only requirement is to use a nine-phase machine in combination with a nine-phase inverter in the powertrain of the EV. This however inevitably brings in further advantages in the propulsion mode, such as increased fault tolerance and the current subdivision into more phases. The benefits of the topology, originally developed for an induction machine, make it interesting for further investigation. Therefore, the performance of the charger is examined here using a permanent magnet synchronous machine (PMSM). The results show that the charger topology is applicable to other types of synchronous machines and is, even more importantly, independent of the angular spatial shift between the individual three-phase windings of the nine-phase machine's stator. The results are comparable with those obtained using an induction machine and confirm the viability of the solution in conjunction with the PMSM as a propulsion motor.

IoT-Based Supervisory Control of an Asymmetrical Nine-Phase Integrated on-Board EV Battery Charger

“…where n ∈ {0, 1, 2} and m ∈ {a, b, c}. By applying the transformation given by (1), the corresponding sequence current components are given in (14) [24]:…”

“…Furthermore, the effect of slot harmonics on the stator current waveform can be mitigated in multiphase machines [13]. The application of nine-phase machines guarantees zero average torque production during the charging process of EVs because of their higher degrees of freedom [14]. Moreover, nine-phase machines offer an improved line filtering capability through the stator leakage inductances.…”