Closed-Loop Dynamic Control for Dual-Stator Winding Induction Generator at Low Carrier Ratio With Selective Harmonic Elimination Pulsewidth Modulation

In this article, we present a closed-loop dynamic control scheme for a dual-stator winding induction generator (DWIG) with selective harmonic elimination pulsewidth modulation (SHEPWM). This control scheme can be applied in a variable-frequency ac power system based on the DWIG, which is able to operate in low-carrier-ratio conditions, especially in high-power aeroapplications. Common closed-loop induction machine control schemes, such as vector control strategy, generally lead to control failure with SHEPWM implemented. This proposed closed-loop dynamic control scheme makes the dynamic operation of the DWIG power system feasible with SHEPWM. The scheme consists of three main parts: the complex-signal observer for DWIG, outer loop controller for DWIG, and stator flux-linkage trajectory tracking controller. The complex-signal observer provides the extra steady-state components of control signals by using the complex coefficient filter. The outer loop controller provides the dynamic commands for control signals. Finally, the flux-linkage trajectory tracking control (FTTC) synthesizes these signals and serves as the inner loop. The simulation and experimental results verify the validity and effectiveness of the proposed scheme.