An efficient control of a series connected two-synchronous motor 5-phase with non sinusoidal EMF supplied by a single 5-leg VSI: Experimental and theoretical investigations

This paper proposes the control scheme of an original drive which is made up of two 5-phase permanent magnet synchronous machines (PMSM) connected in series. Even if the Electro-Motive Forces (EMF) are trapezoidal, it is possible, by using a special series connection between the two machines and by implementing a special vector control, to impose independent torques and speeds with a single five-leg Voltage Source Inverter (VSI). If special series-connection with classical vector control is sufficient to achieve flux/torque decoupling when the EMFs are sinusoidal, it is necessary to modify the control scheme when the EMFs are not sinusoidal.Simulations and experimental results demonstrate the efficiency of the independent control of the two 5-phase synchronous machines connected in series, and the efficiency of the proposed improved control for different loads.

► The basis of an independent control of two 5-phase PM machines, connected in series to a single inverter, are presented.
► The influence of the harmonics of the EMF of the PM machines in the behavior of the system is discussed.
► An original strategy to determine optimal torque reference of each PM machine is presented.
► Experimental and simulation results demonstrated the efficiency and the robustness of the proposed strategy.
► The presented strategy leads to reach high level requirements in terms of torque quality.