Design considerations for an automotive integrated starter-generator with pole-phase modulation

Automotive manufacturers worldwide are investigating the introduction of new technology into their products to reduce fuel consumption and emissions. The new 42 V ISO draft standard for passenger automobiles makes an integrated starter-generator both a possibility and a necessity. This paper first examines the required properties of this new system and then goes on to define what we believe to be the most appropriate system configuration. In the process, methods for extending the speed range of an induction machine are analyzed and a new method for an efficient pole changing technique, called pole-phase modulation (PPM), is described. The control of such a novel drive is given, for both motoring and generating operation, including transition from one to the other mode. Experimental results, obtained on the actual machine are also given.