Effective control of an Integrated Starter-Alternator with an IPM synchronous machine

This paper describes the control strategy of an integrated starter-alternator prototype. Control specifications include a high starting torque in the low speed range as well as a smooth transition from motor to generator operation mode at higher speed. Inverter voltage limitation has to be managed during high speed operation. An interior permanent magnet synchronous machine with a fractional-slot winding is adopted. The control strategy takes advantage of the magnetic model of the electrical machine, which is well suited for flux-weakening application with advantages for the power stage ratings. Details of the control design and experimental test results are reported.