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 the merits and drawbacks of the machines, are summarized. Moreover, the latest development of the machines is also discussed.

A flux-switching permanent-magnet (PM) (FSPM) machine is a new class of stator-PM brushless machines, which offers the advantages of high reliability, high power density, and high efficiency. In this paper, by employing redundant winding in the existing FSPM machine topology, a new redundant FSPM (R-FSPM) machine is proposed for a fault-tolerant operation of critical applications. The redundant winding configuration is analyzed, and the corresponding suitable control strategy for the postfault operation is proposed. The electromagnetic performance of the R-FSPM motor drive under normal and fault conditions is analyzed by using a cosimulation method coupling magnetic and electrical circuit solvers. Finally, a 12-stator-tooth/10-rotor-pole R-FSPM machine is prototyped for verification. Both simulation and experimental results are presented, verifying the fault-tolerant characteristic of the proposed motor drive.

Four wheel independently driven (4WID) electric vehicles are promising vehicle architectures. However, the complex coordination control of the four driving motors and the operation reliability of the vehicle are challenges. In this paper, to address the multimotor coordinate operation against the actuator faults in the 4WID system, combining the adaptive sliding mode (ASM) control and the fault-tolerant (FT) control allocation, an adaptive sliding mode fault-tolerant coordination (ASM-FTC) control is proposed. First, a new vehicle dynamic model with a driving motor fault is set up. In the control layer, an adaptive variable exponential reaching law is used in the ASM to alleviate the chattering and improve the reaching speed, precision, and robustness. Then, the FTC allocation based on the quadratic programming is designed to properly coordinate the four in-wheel motors at the presentation of the motor fault. To verify the proposed control method, a 4WID electric vehicle platform is set up. Simulation and experimental results demonstrate the effectiveness of the ASM-FTC control.

This paper designs a double-side linear vernier permanent-magnet motor which incorporates the merits of high thrust force capability, high power factor and high efficiency. Since the parameters of the motor are very sensitive and the high thrust force capability comes along with the high force ripple, a framework of multi-objective optimization is proposed to improve the overall motor performances. The sensitivity analysis is used to select significant variables and the multi-objective differential evolution with ranking-based mutation operator is conducted with the response surface models to generate the Pareto solution set. The electromagnetic performances of the optimal motor are compared with the initial motor designed by individual parameter analysis step by step based on finite-element analysis. Finally, a prototype motor is manufactured and the experimental results validate the improved motor performances.

A five-phase fault-tolerant permanent-magnet (FTPM) motor can offer high torque density, low torque ripple, and good fault-tolerant capability. In order to improve operation performance under an open-circuit fault condition, this paper proposes a new remedial field-oriented control (RFOC) strategy for a five-phase FTPM motor. The novelty of the proposed RFOC strategy lies in the orthogonal reduced-order transformation matrix, which is derived from the fault-tolerant current references, and a new zero-sequence current related to torque ripple. The pulsation of the neutral voltage can be neglected in the RFOC strategy, having no effect on the control action. Also, the effect of the open-circuit fault on the motor drive model under the transformation matrix is discussed. A five-phase FTPM motor drive is prototyped and the proposed RFOC strategy is evaluated in terms of the steady-state and dynamic performances. The simulated and experimental results are given to verify the proposed strategy.

In this paper, a complementary and modular linear flux-switching permanent magnet (MLFSPM) motor is investigated, in which both the magnets and armature windings are placed in the short mover, while the long stator consists of iron core only. The proposed MLFSPM motor incorporates the high power density of a linear permanent magnet synchronous motor and the simple structure of a linear induction motor. It is especially suitable for long stator applications such as urban rail transit. The objective of this paper is to build the mathematical model for the purpose of control of this motor. The simulation results by means of finite-element analysis (FEA) verified the theoretical analysis and the effectiveness of this model. Both the analytical model and the FEA results are validated by experiments based on a prototype motor.