Design of an integrated motor/controller drive for an automotive water pump application

This paper addresses key technical issues in the design of an integrated motor/controller drive unit for which the electric motor, its electronic controller, and load (a pump impeller) are all combined into a single structural assembly. A cost-based trade-off study is described that includes five different types of brushless machines, leading to the selection of an interior PM synchronous machine as the preferred prime mover for this application. The physical configurations of the motor and the controller were designed in order to minimize weight and volume while maximizing their cooling effectiveness. Several key issues associated with the controller design are described, including the physical layout of key components, the development of the EMI filter to meet automotive specifications, and analysis of worst-case component temperature rises using finite-element thermal analysis.