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This paper proposes a d–q cross-coupling current controller for permanent magnet synchronous motor (PMSM) drives. Slotting and cross-coupling effects in PMSMs cause the effective air-gap length to vary with the rotor angle and distort the distribution of the air-gap flux. Such distortions have a significant influence on the current control by changing the relationship between the stator currents and voltages. To investigate their effects, a d–q model is established in this paper, which is suitable for describing the voltage characteristics of the actual PMSMs. The model contains the angle-dependent parameters, the cross-coupling inductance between d–q axes, and the q-axis permanent magnet flux linkage, unlike the ideal d–q model. The transfer function matrix from the d–q currents to d–q voltages of PMSM is newly derived from the model. Based on that, the current controller with the feedback and feedforward terms of 2-by-2 matrix is proposed. It is designed so that the independent gains are in low-pass filter forms and the coupling control gains are zero with eliminating interference between d–q axes. The proposed controller contributes to providing the stable control performance by canceling the slotting and cross-coupling effects. The performance of the proposed current controller is verified by experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a novel drive method for interior permanent magnet machines (IPMMs). In the proposed system, a two-phase IPMM is fed from a single-phase H-bridge inverter for low-cost applications. Its main winding in d -axis is connected to the inverter and the auxiliary winding in q-axis is inherently short circuited. This configuration enables the motor to operate in a wider speed range with higher energy efficiency than most other single-phase drive systems. Also, its torque capability in the high-speed range is as high as that of the three-phase IPMM drive despite the reduced power devices, drivers, and current sensors. Accordingly, the proposed system has benefits such as simple structure, low cost, high-power density, and improved efficiency. In this paper, the system is modeled with an equivalent three-phase machine. Based on the model, its torque characteristics and operating areas are analyzed and compared to those of the conventional IPMM drives. A speed control algorithm is also developed. It includes a maximum torque per ampere control to improve drive efficiency and a flux-weakening control to maximize the feasible inverter output voltage. The proposed system and control algorithm are verified by experimental results. [ABSTRACT FROM PUBLISHER]

This paper develops an online interturn fault diagnosis method for permanent magnet synchronous machine (PMSM). The mathematical model of the PMSM with interturn fault is established. The zero-sequence voltage component and zero-sequence current component are analyzed in the PMSM, respectively. Then, the new fault indicators are defined to remove the influence of the variation of the rotor speed and an effective frequency tracking algorithm is presented to extract fault indicators. In this proposed method, not only the interturn fault can be effectively detected, but also the phase in which this fault occurs can be accurately identified. The experiments are carried out and the experiment results verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a novel hybrid excited generator, which is suitable for a variable-speed wind power generation system. Two sets of excitation sources are employed, which are permanent magnets (PMs) on the rotor and the field windings on the stator. The rotor is design with PM-iron structure, namely the PMs and iron poles are alternatively located in rotor, which can provide PM excitation and flux modulating simultaneously. Meanwhile, the adjacent stator teeth are designed with different height, which enables the stator with flux modulating effect, and, therefore, bidirectional flux modulating can be achieved. Some specific harmonics excited by the rotor PMs can be effectively adjusted by the field current, and the back electromotive force and electromagnetic torque can be regulated accordingly. Therefore, the proposed generator can achieve constant voltage control and maximum power point tracking control by controlling the field current. The design considerations and field regulating principle are analytically investigated. An improved Tabu search algorithm is used to optimize the proposed generator, and finite-element method is used to realize preliminary study of the electromagnetic performances. A prototype is manufactured and experimental tests are conducted to verify the theoretical analysis and control strategies. [ABSTRACT FROM PUBLISHER]

Hybrid-excitation switched reluctance motors (HESRMs) have attracted considerable attention for various drive applications due to their simple structure, low cost, and high-torque/power capabilities. This paper comprehensively evaluates and compares a high-torque segmented-stator HESRM drive with a conventional SRM drive in terms of static magnetic and dynamic performances. The stator of the segmented HESRM consists of six individual U-shaped segments; each one has two teeth associated with a permanent magnet (PM) installed between them. The static magnetic characteristics of a segmented HESRM and a conventional SRM, including flux distribution, phase flux linkage, electromagnetic torque, are analyzed and compared. The total fluxes created by the PM and by the excited current are strongly coupled. The details of mathematical model as well as dynamic performances of the segmented HESRM is derived and compared with the conventional SRM. Finally, a segmented HESRM and a conventional SRM of the same size are prototyped for experimental verification. From the comparative study, it is indicated that the segmented HESRM has better characteristics than the conventional SRM, such as less iron consumption, higher static and dynamic average torque production, lower torque ripple, higher power and torque densities, higher efficiency, and stronger starting capability. The measured results of static magnetic characteristic, steady-state and transient performances, and torque–speed characteristic of two SRM drives verify the finite-element analysis, modeling, and corresponding predictions. [ABSTRACT FROM PUBLISHER]

The aim of this study is to introduce the maximum torque per total ampere (MTPTA) control strategy for brushless doubly fed induction machine drives taking iron loss into account. In this regard, the condition for realizing the MTPTA is investigated in the presence of iron loss by a theoretical approach. It is shown the proposed strategy is realized when the MTPTA criterion tracks zero as reference signal. As a result, the current is not only shared between the stator windings fairly but also total stator currents are minimized for a given torque. The experimental results confirm the performance of the proposed control strategy. [ABSTRACT FROM AUTHOR]

A sensorless algorithm is developed on the basis of a rotor flux observer in the stationary frame. In particular, it involves a parameter adaptive algorithm for an initial rotor flux like the observer, which was recently proposed by Bobtsov et al. (Automatica, vol. 61, Nov. 2015). In the proposed method, the flux observer is linked to the parameter estimator via a compensating term that results from parameter error. This method has a robust property against dc bias errors, i.e., it cures the inherent weakness of the pure integrator (flux observer) to dc offsets that frequently occur in current measurements and voltage estimates. The robust performance is demonstrated through simulations and experimental results. [ABSTRACT FROM AUTHOR]