Small electric vehicle drive control according to maximal efficiency criteria

This paper deals with induction drive control implementation according to the requirement of maximal efficiency for a traction application in a small electric car. Optimum setting of the motor slip frequency was found according to the criteria of maximal motor efficiency in a wide range of torque and speed (see [1] and [2]). The traction drive is an application without any extreme dynamic response requirement. It is possible to use scalar control strategies without any significant impact on the vehicle dynamic behavior. An implementation of the optimum motor setting into a scalar control is described in this article. Optimum rotor frequency and stator current look-up tables for any operating point in the used range of desired torque and actual speed were generated and used in common induction machine scalar control schemes.