Integrated-Starter/Alternator with Sensorless Ringed-Pole PM Synchronous Motor Drive

The so called Integrated-Starter/Alternator (ISA) is a high efficiency electrical machine that is connected to an Internal Combustion Engine (ICE) obtaining a mild hybrid electric vehicles. The ISA has a twofold task: starting-up the engine and generating electrical energy to be stored into a battery. This paper is focused on the first task. Two different motor are taken into account: an external rotor SPM machine and an IPM machine. For the control drive both the rotor configuration require the knowledge of their rotor position, then a sensorless technique based on the high frequency voltage injection for rotor position detection has been implemented. In order to create a high frequency anisotropy in the SPM rotor configuration, a ringed-pole solution has been adopted. Experimental tests have highlighted that the first machine has a good performance starting up the engine with a good speed and position estimation in spite of the particular no constant load. As regard the IPM machine, with this machine the sensorless engine start-up is not possible because at high current the anisotropy disappear a cause of saturation effects.