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A Dual three-phase winding configuration in a 12-slot 10-pole Brushless Alternative Current Synchronous Motor (BLAC) has been adopting in electrical power steering systems. The main aim of this winding configuration is to get a fault tolerance capability when the motor is a failure. Different arrangements of the coils of the windings are possible to separate the three-phase winding. In this paper, we investigate the effect of the various winding configurations for the fault tolerance on the iron losses of the BLAC motor. To calculate accurate iron losses, we use the instantaneous distribution of magnetic flux from a two-dimensional finite-element method. As a result, we suggest the most effective winding configuration to make the BLAC motor efficiency in the event of the fault.

정현파 전류 구동의 분수 슬롯을 갖는 영구자석 동기 전동기는 코깅 토크 저감 측면에서 장점을 갖기 때문에 하이브리드 및 전기자동차의 전기조향장치시스템에 적용이 가능하다. 이러한 전동기는 그 목적에 따라 이층권 및 단층권 등의 다양한 형태의 고정자 권선 방법을 적용하고 있는데, 본 논문에서는 여러 가지 고정자 권선 방법에 따른 영구자석 동기 전동기의 철손 특성을 정밀 분석하였다. 이를 위해 시간 고조파를 고려한 철손 해석 기법을 사용하였으며, 유한요소 해석에 의해 얻어진 순시 자속밀도로부터 히스테리시스손 및 와전류손을 계산하였다. 해석 결과, 각 권선 방법에서 대부분의 철손은 고정자에서 발생하였으며, 철손밀도는 자계의 변화가 교번자계 특성을 갖는 치와 요크에서보다 회전자계의 특성을 갖는 고정자 치 끝단부에서 가장 높게 분포하였다. 또한 부하에 따른 철손은 정격부하 이하에서 단층권이 이층권에 비해 철손이 작았으며, 부하가 증가할수록 자기회로의 포화로 인해 단층권에서 급격히 철손이 증가함을 알 수 있었다.

This paper proposes an analytic model for four-switch inverter (FSI)-driven wye (Y) or delta (Δ)-connected motors with a current ripple reduction algorithm. FSIs employ four switches in controlling three-phase load instead of using six switches. They have split dc-link stage, and due to this inherent structure there exists the voltage difference between upper and lower capacitors, which results in distortion of the inverter output voltage. To study characteristics of FSIs, this paper presents an advanced simulation models of FSI-driven control system for 3-phase motor that can has a wire connection either Y or Δ. In addition, this paper introduces a current ripple reduction scheme that mitigates degradation of control performance due to the voltage difference between the dc-link capacitors. The validity of the proposed method and the analytic model is verified by simulations and experiments carried out with 1-HP induction machine with Y or Δ-connection

This paper presents a nonlinear sliding mode control (SMC) scheme with a variable damping ratio for interior permanent magnet synchronous motors (IPMSMs). First, a nonlinear sliding surface whose parameters change continuously with time is designed. Actually, the proposed SMC has the ability to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time and eliminates the singularity problem with the upper bound of an uncertain term, which cannot be measured in practice, by using a simple adaptation law. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. Moreover, a simple sliding mode observer is used to estimate the load torque and system uncertainties. The effectiveness of the proposed nonlinear SMC scheme is verified using comparative experimental results of the linear SMC scheme when the speed reference and load torque change under system uncertainties. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and less sensitivity to system uncertainties than the linear SMC method.

This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.