Torque sharing function control of switched reluctance machines with reduced current sensors

This paper presents a Torque Sharing Function (TSF) control of Switched Reluctance Machines (SRMs) with different current sensor placements to reconstruct the phase currents. TSF requires precise phase current information to ensure accurate torque control. Two proposed methods with different chopping transistors or a new PWM implementation require four or two current sensors to replace the current sensors on each phase regardless of the phase number. For both approaches, the actual phase current can be easily extracted during the single phase conducting region. However, how to separate the incoming and outgoing phase current values during the commutation region is the difficult issue to deal with. In order to derive these two adjacent currents, the explanations and comparisons of two proposed methods are described. Their effectiveness is verified by experimental results on a four-phase 8/6 SRM. Finally, the approach with a new PWM implementation is selected, which requires only two current sensors for reducing the number of sensors. The control system can be more compact and cheaper.