Space Vector PWM for Three Series-Connected Permanent Magnet Synchronous Motors Drive System

Since multiphase machines have more additional degree of freedom than three-phase machine, which can be utilized to control other machines, a number of machines can be controlled independently. The stator windings of the machines can be series connected by an appropriate phase transposition, with the supply coming from a single multiphase inverter. This paper proposed a novel series-connected system, composed of two dual three-phase permanent magnet synchronous motors (PMSMs), one two-phase PMSM and a seven-phase voltage source inverter (VSI) and controlled using space vector PWM. In such a way, independent control of the three series-connected PMSMs is achieved. The simulation results indicated that three machines can operate independently while taking three different loads, supplied from the same seven-phase inverter.