Operating Principle and Characterisation of a Novel Contra-Rotating Dual-Rotor Switched Reluctance Machine

This paper proposes a novel dual mechanical port machine composed of a stator with a single set of windings with two coaxially housed rotors which are capable of rotating in opposite directions. This topology makes the machine suitable for applications in renewable energy as well as in hybrid drive systems. A torque characteristic in function of the switch-on angle is derived for each rotor from which the possible operating modes of the whole machine are established. Due to the fact that two rotors are magnetically coupled to a single stator winding, the total back-emf is the result of the superposition of the back-emf produced by each rotor separately. The modulating effect of the relative position of the rotors on the back-emf profile is validated for a range of operating modes by means of simulation and experimental results. The results show that when the machine is operating as a transmission, with one rotor motoring and the other generating, the total time-average back-emf profile is zero.