To realize the online observation of the flux linkage of interior permanent magnet (PM) synchronous machine for electric vehicles after uniform demagnetization under multiple operating conditions, an improved model reference adaptive system (MRAS) flux linkage observer is proposed based on a novel double closed-loop control approach in this article. First, a double closed-loop control strategy of interior permanent magnet synchronous motor (IPMSM) is established employing maximum torque per ampere (MTPA) and sliding mode controller (SMC). The MTPA significantly improves the current utilization and system efficiency, and the SMC is applied to replace the traditional PI velocity loop controller to increase the anti-interference capability of the whole system. Then, the MRAS and single neuron adaptive proportional integral (SNPI) algorithm are adopted to develop an SNPI-MRAS flux linkage observer, which can modify the adaptive law of the MRAS online and overcome the shortage of low observation accuracy of traditional PI-MRAS flux observer when the machine parameters change. Next, a feedback gain matrix term is inserted in the SNPI-MRAS, which can guarantee that the linear forward channel of the SNPI-MRAS is a strictly positive real matrix. Finally, the effectiveness of the proposed method is verified. The outcomes demonstrate that the proposed method can effectively improve the dynamic response of the observer and increase its accuracy and convergence speed.

In this paper, a novel limited swing angle torque permanent magnet motor (LSATPMM) is proposed, and the operating principle of the circuit breaker of the proposed LSATPMM and a mathematical model are analyzed. The characteristics of the high voltage circuit breaker (HVCB) of the proposed machine are analyzed and calculated by numerical finite element analysis methods. The co-simulation of the Maxwell Circuit Editor and Ansoft Maxwell is used to analyze the dynamic characteristics of HVCB. The advantages of the presented operating mechanism for LSATPMM, such as the ability to adjust the opening and closing torque characteristic, high reliability, robust drive system and fault tolerance, are discussed. Finally, a prototype of LSATPMM is created and tested; and the characteristic curve of position versus torque is acquired in order to confirm the proposed design.

This article presents an improved transient temperature evaluation method for permanent magnet synchronous machine (PMSM) based on the lumped parameter thermal network (LPTN) and the segmented iron loss calculation model with compensation terms. The modeling methodology for the proposed iron loss calculation model (PILCM) is given in detail, including the process of model establishment and parameter determination. By introducing the compensation term of eddy current loss and hysteresis loss in different frequencies and magnetic density ranges, the loss characteristics of the proposed model demonstrate higher computational accuracy than conventional iron loss calculation model (CILCM), which can be confirmed by magnetic characteristic testing experiments of lamination steel. In addition, an experimental platform of the temperature rise is built for evaluating the temperature of end winding, the absolute error of the LPTN + PILCM and the LPTN + CILCM under rated condition are $1~^{\circ }$ C and $2.3~^{\circ } $ C, respectively. The error of overload running time predicted by LPTN + PILCM under two overload conditions are 3.6% and 5.3%, respectively, which has higher accuracy than the results of 11.7% and 13.1% predicted by LPTN + CILCM.

In this article, a sensorless control method based on signal injection and a high-pass filter (HPF) circuit is presented to control the unsymmetrical bistable multimagnetic circuit permanent magnetic actuator. In this method, a high-frequency sinusoidal signal was indirectly injected into the idle phase via a HPF circuit, and the peak of the high-frequency capacitance current was measured, which was used to calculate the idle phase inductance. Thereafter, the mover position was calculated by the one-to-one relationship between the idle phase inductance and the mover position. Combined with the HPF circuit and the proposed average current peak algorithm, the influences of back-EMF and coil resistance were eliminated. The magnetic saturation effects can also be ignored in the proposed strategy. The estimated noise, caused by measurement noise and signal distortion, was filtered using a simple mathematical filter. The flexibility and accuracy of the presented strategy were verified by simulation and experimental investigation.

A new type of double‐stator permanent magnet spherical motor (DSSRPMSM) is proposed. Compared with most existing spherical motors, this motor uses a large number of stator iron cores, which can generate larger magnetic flux density and significantly improve torque capacity. The proposed DSSRPMSM can continuously rotate, swing and spiral, and can be used in the multi‐degree‐of‐freedom motion fields of industrial robot joints, moment gyroscopes, panoramic photography tables and so on. Because the motor has the dual characteristics of rotary motor and arc linear motor, the comprehensive effects of stator slotting and stator iron core breaking should be considered. Cylindrical and trapezoidal PM poles are equivalent to dihedral PM poles, and stator coils are equivalent to PM pole models. Analytical models of PM pole magnetic field and stator magnetic field in a spherical coordinate system are established, and the air gap magnetic flux density under unequal magnetic potential boundary conditions is calculated by conformal transformation. The analytical calculation method proposed is consistent with the results of finite element method (FEM) simulation, and the experimental test further verifies the effectiveness and accuracy of this method.

In this paper, a novel asymmetrical bistable short mover permanent magnet actuator is presented. The comparisons between the presented machine and the asymmetrical structure bistable permanent magnet actuator are introduced. The static and dynamic characteristics of the high-voltage circuit breaker with the presented machine are calculated and discussed. The influences of the length of the mover and the initial mover position in the presented machine are studied and researched. The merits of the presented machine, such as less permanent magnet volume, low cost, small mover mass, and high starting speed, are researched and discussed. The Genetic Algorithm is used to optimize the presented machine. Finally, a conventional permanent magnet actuator prototype is created and tested on account of the limited experimental conditions. The characteristic curves of position versus retaining force are acquired to confirm the proposed design.