Permanent magnet (PM) brushless machines having magnets and windings in stator (the so-called stator-PM machines)have attracted more and more attention in the past decade due to its definite advantages of robust structure, high power density, high efficiency, etc. In this paper, an overview of the stator-PM machine is presented, with particular emphasis on concepts, operation principles, machine topologies, electromagnetic performance, and control strategies. Both brushless ac and dc operation modes are described. The key features of the machines, including themerits and drawbacks of the machines, are summarized.Moreover, the latest development of the machines is also discussed.

In a doubly salient permanent-magnet (DSPM) motor drive, it is difficult to get satisfied control characteristics by using a normal linear proportional plus integral (PI) controller due to the high nonlinearity between speed and current or torque. Hence, a new self-tuning fuzzy PI controller with conditional integral, which is performed by a single-chip N87C196KD, is proposed. The initial parameters of the controller are optimized by using genetic arithmetic. Simulation and experiments on the newly proposed 8/6-pole DSPM machine have shown that the proposed new self-tuning fuzzy PI controller offers better adaptability than the normal linear PI control and that the developed motor drive offers better steady-state and dynamic performances.

In this paper, magnetic field analysis of a new doubly salient permanent magnet (DSPM) motor is carried out based on finite element method (FEM). Hence, the corresponding static characteristics, including PM flux linkage, self-inductance, mutual inductance, and static torque are deduced (the interaction between the PM field and armature field are taken into account). New methods for measuring the motor inductance are also proposed. The theoretical analysis is verified by experimental results.

This paper presents the design and analysis of a new doubly salient permanent magnet (DSPM) motor. The corresponding output power equation is analytically derived. The initial calculation of motor dimensions and parameters, namely, the core diameter, stack length, permanent magnet size, and winding turns, are also discussed. An 8/6-pole DSPM motor is designed and built for exemplification. Moreover, finite element analysis of this motor is carried out to investigate the magnetic field distribution at different rotor positions and load currents, in which the leakage flux outside the stator circumference of the DSPM motor is firstly taken into account. Hence, the characteristics of the proposed motor are deduced. Experimental results of the prototype are given to verify the theoretical analysis and to confirm its high efficiency.

提出了一种新型分裂绕组双凸极变速永磁（doubly salient permanent magnet，简记为DSPM）电机，对其磁场、静态特性、控制策略等进行了系统深入的理论和实验研究。在理论上，给出了DSPM电机的稳态和动态数学模型，进而导出了该电机的输出方程，并论证了采用分裂绕组拓展电机转速范围的可行性。用有限元法分析了电机磁场，计及该电机所特有的外漏磁。根据DSPM电机工作原理和静态特性，提出相应的控制策略，制定了控制方案，并在以单片机为核心的控制器上实施。针对4相8/6极电机的特点，提出了无中线四相半桥式功率变换器拓扑结构，简化了控制系统。样机实验结果不仅验证了理论分析的正确性，而且表明该新型电机驱动系统具有优良的稳态和动态性能，在很宽的功率范围内具有高效率，分裂绕组能有效拓展电机行范围。

In this paper, a nonlinear varying-network magnetic circuit (VNMC) modeling method is developed for doubly salient permanent-magnet (DSPM) motors. The method is used to analyze the static characteristics of DSPM motors by specific permeance calculations, in which the interaction between the permanent-magnet field and the armature current field, as well as magnetic saturation, are taken into account. Two newly proposed DSPM motors (12/8-pole and 6/4-pole) are used as examples. There is good agreement between the results of the nonlinear VNMC modeling method and finite-element analysis. Moreover, the nonlinear VNMC method offers the advantage of calculating, effectively and efficiently, the static characteristics of DSPM motors having different dimensions, parameters, and conditions. Finally, the proposed method is verified by experimental testing of a 6/4-pole prototype.

This paper proposes a new 8/6-pole doubly salient permanent-magnet (DSPM) motor drive, which offers the advantages of higher power density, higher efficiency, and wider speed range. The corresponding control and operation of the motor drive are presented. A variable proportional-integral (PI) controller combined with bang-bang control for the DSPM motor drive is developed. Two operation modes, namely, four-phase and two-phase operation modes, are proposed for the 8/6-pole DSPM motor drive. The drive system is implemented and tested. The results show that the developed control scheme can operate the DSPM motor properly, and the DSPM motor drive offers high efficiency over wide power range and good dynamic performance. Furthermore, the two-phase operation mode of the 8/6-pole DSPM motor offers the possibility of eliminating the torque ripple of the motor drive.

The inductance characteristic of doubly salient permanent magnet (DSPM) motors is the basis of design, analysis, and control of the motor. Due to the nonlinearity and doubly salient structure of the motor, this characteristic is a function of not only the rotor position, but also the strengthening and weakening actions of the armature flux to the permanent magnet (PM) flux, which makes the measurement of inductance difficult. This article proposes new methods for the measurement of the motor inductance for any rotor positions and level of excitation. The methods are applied to the two newly proposed DSPM motors and the results are compared with those obtained by finite element analysis. It is shown that the proposed peak value method can correctly reflect the influence of the strengthening and weakening actions of the armature flux to the PM flux on the inductance of DSPM motors.