High efficient wheelchair drive with PM synchronous motor

A project of a converter fed synchronous motor in a wheelchair drive is presented in this paper. The project is the continuation of previous work on synchronous wheelchair drives, based on 24 volts supplying voltage. This time, to avoid the constrains connected with low voltage, the authors propose a new configuration for the converter with a boost chopper and an inverter working on higher voltage. Special care was taken in designing the boost chopper, as this part of the circuit has the greatest influence on the overall efficiency of the drive. For generating inverter control signals a new algorithm was proposed. The features of the new algorithm and the limitations of the 8 bit system implementation were then discussed. The control strategy chosen for the drive assures near maximum operational efficiency of the motor. Finally the overall efficiency of the drive was analysed and compared to DC drive performance