Dual Volts-per-Hertz Control of Double-Inverter-Fed Wound Rotor Induction Machine

A double-inverter-fed wound rotor induction machine (DI-WRIM) is a two-port machine capable of maintaining rated torque even at twice the rated speed. Such machines are gaining popularity in high-speed and high-power applications for their versatility and degrees of freedom in control. The existing control methods for the DI-WRIM are all based on the dynamic model of the machine, and the associated controller structures are complex with multiple controllers. This article proposes a novel control scheme for the DI-WRIM based on the steady-state model, which requires only one controller. The proposed control scheme has the capability to operate the machine in both sub- and supersynchronous modes in all the four quadrants in the torque–speed plane. The simplicity of the proposed dual volts-per-hertz control method can be compared to the very popular scalar control used in cage rotor induction machine drives. Mathematical derivation of the control law with appropriate approximations is discussed. Experimental results are presented from a 5-hp eight-pole wound rotor induction machine drive.