Variable phase-pole machines have the potential to extend the operational range to higher speeds through magnetic pole changes. The state-of-the-art vectorspace decomposition cannot model the transient behavior of the pole change for any possible phase-pole configuration as it creates a discontinuity. The proposed harmonicplane decomposition theory solves this issue by generalizing the vector-space decomposition to the fullest extend by using its discrete Fourier transformation interpretation. The theory for indirect rotor field-oriented control is developed using the harmonic-plane decomposition. A controlled, loaded pole change on a wound independently-controlled stator-coils machine using two transition strategies shows the harmonic-plane decomposition-based controller's ability to maintain torque in the transition. Additionally, the proposed controller accomplishes real harmonic injection and balanced steady-state operation.

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In this paper, lumped parameters for a variable phase-pole induction machine with wound independently controlled stator coils are computed using finite-element simulations. Differently from finite-element simulations of conventional electrical machines, this solution uses a per-solenoid approach.

Variable phase-pole machines are envisioned in applications requiring a large torque-speed operating area. The control of these machines relies on accurate models and parameters but research on parameter identification methods is scarce. This paper presents an offline parameter-identification method for variable phase-pole machines adopting a harmonicplane decomposition model. The method employs standard tests with single-frequency excitation in multiple pole configurations and uses the results to minimize a constrained, regularized weighted least-squares problem. Good agreement is exhibited in simulations when comparing a harmonic-plane decomposition model of a variable phase-pole machine using the inferred parameters to a benchmark vector-space decomposition model implementing parameters identified in the standard tests. The paper emphasizes the importance of performing measurements in multiple pole configurations and weighing these measurements appropriately to render an accurate set of parameters.

Multiphase electrical machines have the inherent advantage of fault tolerance as compared to conventional threephase machines. A special category of multiphase electrical machines are variable phase-pole machines, which allow a change between phase-pole configurations without hardware reconfiguration, but merely through current control. This paper proposes an open-fault detection method for variable phase-pole machines; fast, non-invasive, parameter-and operation-independent. The method analyzes the space harmonics of the current distribution using the harmonic plane decomposition theory, which is already used to perform a seamless switch between phase-pole configurations. Simulation results demonstrate the feasibility of the approach.