Parameter auto-tuning for a linear permanent magnet synchronous motor drive

No-lapping concentrated windings permanent magnet linear synchronous motor (PMLSM) which possesses notable advantages such as big thrust force density, short winding head and small magnetic resistance is the preferred drive motor on Linear motor cordless upgrade system. In the paper 15 slots 16 poles PMLSM has been taken as example. On the basis of d-q dual-response theory, key parameters such as the motor resistance of q-axis (quadrature) and d-axis (direct) have been calculated by Finite Element Method. Thus mathematic model of PMLSM steady-state analysis has been built. PMLSM performances such as current, thrust force, power factor, efficiency, and electric power brake force affecting by supply voltage and ambient temperature change have been studied respectively both on load condition and no-load condition. The experiment results agree with theoretical analysis, with good prospects of permanent magnet (PM) linear synchronous motor for design and application of ropeless elevator.

A new transfer model vehicle system for automatic horizontal transport, especially in short-turning-area applications, has been developed in the authors' laboratory. It is driven by permanent magnet (PM) linear synchronous motors (LSMs), and can operate efficiently in orthogonally-crossed-guideway network in mass-reduced mode. This paper presents a fundamental study of the PM LSM vehicle running on such network guideways with two crossings. The experimental results have shown a good agreement of the vehicle motion with the demand pattern in network running operation.

Linear motor eliminates the middle part of mechanical drive train, but because of structural characteristics of itself, must to take effective measures to reduce thrust fluctuations, or direct drive will lost its original meaning. In this paper, firstly research on detent force of moving magnet type permanent magnet synchronous linear servo motor and analyze the principle of generate detent force, secondly analyze the cogging force of moving magnet type permanent magnet synchronous linear motor and obtain the expression of cogging force maximum value, finally propose effective method to reduce detent force.

Because of the uncertainty’s action in a linear permanent magnet synchronous motor drive system such as the external load force, the cogging force, the column friction force and the Stribeck effect force and the parameters variations, it is difficult to reach specific control performances by using the existing linear controller. To raise robustness under occurrence of parameters uncertainties and external force disturbances, the smart backstepping control system with three adaptive laws is proposed for controlling the linear permanent magnet synchronous motor drive system. In accordance with the Lyapunov function, three adaptive laws are derived to ameliorate the system’s robustness. Furthermore, the smart backstepping control system using revised recurrent fuzzy neural network and revised ant colony optimization with the compensated controller is proposed to improve the control performance. The revised recurrent fuzzy neural network acts as the estimator of the uncertainty’s disturbances. In addition, the compensated controller with error estimation law is proposed to compensate the minimum rebuilt error. Moreover, two learning rates of the weights in the revised recurrent fuzzy neural network are derived according to the discrete-type Lyapunov stability to assure convergence of the output tracking error and are adopted by using the revised ant colony optimization to speed-up parameter’s convergence. Finally, some comparative performances are verified through some tentative upshots that the smart backstepping control system by virtue of revised recurrent fuzzy neural network and revised ant colony optimization with the compensated controller results in better control performances for the linear permanent magnet synchronous motor drive system.

Thrust performance is one of the important indexes of permanent magnet linear synchronous motors. The traditional non-oriented silicon steel sheet is used as the core material of the permanent magnet linear synchronous motor, which limits the performance of the permanent magnet linear synchronous motors. For the oriented silicon steel sheet has a higher magnetic permeability in the rolling direction, a permanent magnet linear synchronous motor with similar number of poles and slots made of oriented silicon steel is proposed in this paper. By measuring the B-H curves of the rolling direction and the cutting direction, the thrust properties of the two motors made of traditional silicon steel sheets and oriented silicon steel sheets are analyzed and compared by the finite element method (FEM) under rated load and overload conditions respectively. The thrusts under different tooth-yoke ratios are discussed in the end.

The permanent magnet linear synchronous motors (PMLSM) are proposed for many applications ranging from ground transportation to reciprocating servo system and conveyance system for their simple structure and high performance. Generally, the acceleration and deceleration experiment of PMLSM is very difficult because it has restricted limits of operating. Therefore, this paper proposes disk type PMLSM in order to solve problem stated above. Since the proposed disk type PMLSM has infinite operation limits, it can be solved a problem in acceleration and deceleration experiment of PMLSM. This paper also deals with the analysis of disk type PMLSM considering slot opening and skew effect for a various air-gap length, in terms of air-gap flux density and detent force.

In permanent magnet linear synchronous motor (PMLSM) direct drive system, disturbance caused by load disturbance and perturbation of motor parameters would reduce the control precision in a certain extent. In order to restrict the disturbance in PMLSM direct drive system, a vector control (VC) strategy based on the disturbance observer (DOB) was proposed in this investigation. By using the observed disturbance of DOB to adjust the given value of current in speed loop, the compensation for a sudden disturbance is optimized and a high precision of PMLSM drive system is obtained. For the sake of improving the dynamic performance under unknown disturbances, the traditional PID controller in speed loop was replaced by a single neuron PID controller, which leads to a good adaptive capability and a better starting performance in a given speed. Finally, a higher steady precision and robustness would be realized.

Permanent magnet linear synchronous motors (PMLSM) offer several advantages over their rotary counterparts in many precision manufacturing applications requiring linear motion, which can achieve a much higher speed and a higher position accuracy. However, linear motors are more sensitive to disturbance and parameter variations. Furthermore, the linear motor systems are subject to significant nonlinear effects due to friction and force ripple. A sliding mode controller with an adaptive disturbance observer is processed to achieve high accuracy in the presence of external disturbance and parameter uncertainty. The position control for the gringding machine of a PMLSM feed drive using the proposed control strategies is illustrated. Simulation results show that the proposed controllers provide high-performance dynamic characteristics and are robust with regard to external load disturbance.

In this paper, the maximum thrust force per ampere (MTPA) strategy for saturated permanent magnet linear synchronous motors over the entire field weakening region is presented. In other words, influence of magnetic saturation on the MTPA and field weakening strategies as well as motor-inverter limitations is considered. Using the modified MTPA strategy leads to minimized copper losses, and so maximum capacity of motor is utilized. The proposed scheme incorporates all optimal strategies and operates the drive within the voltage and current limits of the motor/inverter. Simulation results for a prototype interior permanent magnet linear synchronous motor demonstrate that the MTPA and field weakening strategies can be successfully implemented for vector controlled saturated permanent magnet linear synchronous motor drives.

Currently, the linear motor has replaced the transmission mechanism composed of a rotary motor and a screw, and is widely used in direct drive applications such as computer numerical control (CNC) machine tools. As the thrust density of traditional linear permanent magnet synchronous motor is difficult to be further improved, linear permanent magnet vernier motors (LPMVM) based on magnetic field modulation principle are proposed to improve the thrust density further. A novel LPMVM is proposed in this paper. The topology and operation principle of the proposed LPMVM are introduced. The thrust density of the proposed LPMVM is improved significantly with a simple structure. The end force is analyzed and optimized to decrease the detent force further.

Reduction of the spatial harmonics of back electromotive force(EMF) is a useful way to reduce thrust ripple of permanent magnet linear synchronous motor (PMLSM). In this study, a method of v-skewing in the coils is proposed to reduce the harmonics to suppress thrust ripple in the PMLSM. The thrust and the harmonic are generated in a double-sided PMLSM model. The 3-D finite element method (FEM) is used to build the PMLSM model in consideration of the effect of the v-skewing. Motor platform and testing platform are also built to conduct experimental verification. Simulation results are compared with experiment values. The results indicate that the proposed method is effective for reduction of thrust ripple in double secondary PMSLM.

Permanent magnet linear synchronous motor (PMLSM) has important applications in transportation and industrial control systems for its direct thrust and high power density, etc. Thrust and normal force are the most important criteria for the PMLSM, and numerical methods and finite element analysis (FEA) methods have been conduced to evaluate the forces. In this paper, a prototype has been built to measure the thrust and the normal force of a PMLSM Through investigations with experiments, the traits of the thrust and the normal force have been found out, including the trends versus exciting currents with different amplitudes, different air gap lengths, variable magnetic poles, and different magnet arrangements. Conclusions are drawn through experimental analysis benefit to the electromagnetic design and control scheme evaluation for the PMLSM.

For linear motor system, which is an electromechanical multi-parameter, strong coupling, multi-variable, strong non-linear system, the fact that the system control is difficult to carry out is becoming increasingly prominent. This paper proposes an analysis of relative weights of various factors for thrust fluctuations in permanent magnet synchronous linear motor (PMSLM) based on the Fuzzy Analytic Hierarchy Process, (FAHP). First, the paper analyzes the complexity of PMSLM and thrust fluctuations causes the relevance and variability, pointing out how to reduce the linear motor thrust fluctuation analysis of the existing problems. Then, the paper introduces the theory of fuzzy analytic hierarchy theory and its application characteristics and steps. Finally, the application of fuzzy analytic hierarchy process is proposed to analyze linear motor thrust fluctuation factor weights. The results show the end effect of the thrust fluctuations, the ripple disturbance, magnet distribution and cogging effects. This result can be used as a key intervention to reduce the thrust fluctuation fluctuations for PMSLM.

In order to analyse the electromagnetic field of the permanent magnet linear synchronous motor, the wavelet finite element method is applied to compute the electromagnetic field of it. First, the basic theory of Daubechies' wavelet is studied. Then the wavelet finite element model of the electromagnetic field of permanent magnet linear synchronous motor is constructed. Then simulation analysis of electromagnetic field is carried out by the wavelet finite element method, the traditional finite element method and actual test. And simulation results show that the wavelet finite element method has better convergence and can use fewer wavelet finite elements to get the higher computing precision for computing the electromagnetic field of the permanent magnet linear synchronous motor.

The severe drawback of slotted permanent magnet linear synchronous motor (PMLSM) is the detent force, particularly when accurate positioning and constant low speed is required for numerically controlled machine tool. In this paper, a novel short-armature slotted type multi-segment permanent magnet linear synchronous motor (MSPMLSM) is proposed and constructed to reduce the detent force. It consists of a proper shift of the multiple segments of iron core relative to the PMs. The detent forces of MSPMLSMs with different number of segment are analyzed and simulated by finite element method (FEM). The proposed structure has been proved to be a very effective approach for the reduction of detent force. Then this paper presents the statistical and mathematical optimum design of a 3-segment PMLSM using response surface methodology (RSM) together with FEM to minimize the detent force. Full factorial design and steepest ascent method, one of the iterative search method, is proposed to establish optimal design area for applying RSM. Finally, the global optimal design is predicted and the optimally designed one is manufactured, and the numerical results and measured results are reported to validate the effectiveness of this proposed method.