High efficiency control of IPMSM for electric motorcycles

It is known from the relation between motor torque and armature current phase that there is an optimum current phase at which the maximum motor torque is reached for a given armature current. This means it is a condition of generating torque most effectively for a given armature current. In this paper, a maximum torque per armature current control strategy is proposed. In the proposed control strategy, the armature current phase is assigned upon a Look-up Table (LUT) in accordance with load conditions. The effectiveness of the proposed control is verified through experiments. Because the LUT can be developed with experiments offline, a high efficiency driving can be achieved in a wide load range without complicated online identification of motor parameters. Furthermore, neither torque meter nor power meter is needed in the proposed strategy.