Double-Rotor Electric Variable Transmission Systems

This chapter discusses various double-rotor electric variable transmission (DR EVT) systems, including the system configurations and DR machines as well as the basic and advanced DR types. It presents the corresponding design criteria, design example, and potential applications. With the ever-increasing demand on electromechanical energy conversion, the development of electric machines has been extended from a traditional single-input single-output (SISO) system to a versatile multi-input multi-output (MIMO) system. Similar to the development of traditional machines, the induction DR machine is being challenged by other advanced DR machines, such as the permanent magnet (PM) synchronous DR machine and switched reluctance (SR) DR machine. The aforementioned DR EVT systems, no matter what types of electric machines adopted, all rely on using double rotors to split the engine power in which the electrical power generated by the inner rotor is controlled via the slip-rings and brushes.