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The dual-stator winding induction generator (DWIG) is an alternative main generator in a variable frequency ac power system. So far, the existing studies have not covered the issue of DWIGs excitation controllability, which is a matter of importance for airworthiness. In this article, we develop an impedance-based modeling and analysis technique to investigate DWIGs excitation controllability. Two related topics are presented: the spontaneous self-excitation analysis in uncontrolled system and the implicit internal self-excitation pattern analysis in actively controlled system. In the topic about spontaneous self-excitation, a virtual impulse source technique is developed to derive the impedance-based method properly in the analysis for uncontrolled DWIG. In the second topic, the analysis performed in the presence of a closed-loop controller figures out the same underlying mechanism in both the plant's open-loop stability and the spontaneous self-excitation. The experimental results verify the proposed analysis and techniques that benefit the comprehensive understanding and practical application of DWIG-based power system. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Dual stator-winding induction generator (DWIG) is attractive in stand-alone power systems, and the aim of this paper is to develop the dc generating system of five-phase DWIG with an open phase. First, the relationship between flux and torque is constructed based on the reduced-order transformation, modified flux, and current. Second, the relation between modified voltage and current on the dq plane is constructed. The current of fundamental plane is used for the control loop of the power-winding voltage and control-winding voltage, respectively. Third, the current of the modified secondary subspace plane is used to control the five-phase DWIG operation at minimum control-winding loss. Finally, the simulation and experimental results are given to verify that the amplitude of phase current and output voltage can be regulated effectively by the proposed control strategy. [ABSTRACT FROM AUTHOR]