Integrated motor controlled by multi-inverter with pole-changing functionality and fault tolerance

Energy saving is arguably the most important factor in issues regarding energy and carbon emission. For electric vehicles in particular, saving energy extends the driving range. This can be achieved with a highly efficient variable-speed drive that can cover a wide speed range, and changing the number of poles is one way of realizing such a drive. In addition, electric vehicles must be fault tolerant so that they can still be driven in the event that some components fail. To achieve high performance with pole changing, fault tolerance, and low torque ripple, a motor with two winding groups is combined with two inverters and operated using individual current control. Our results confirm that changing the number of poles allows the motor to operate over a wide speed range in excess of five times the base speed. The new motor has half the torque ripple of a conventional machine and can also continue to drive even if one inverter breaks down.