Contribution to the Full 3D Finite Element Modelling of a Hybrid Stepping Motor with and without Current in the Coils

The paper presents our contribution to the full 3D finite element modelling of a hybrid stepping motor using COMSOL Multiphysics software. This type of four-phase motor has a permanent magnet interposed between the two identical and coaxial half stators. The calculation of the field with or without current in the windings (respectively with or without permanent magnet) is done using a mixed formulation with strong coupling. In addition, the local high saturation of the ferromagnetic material and the radial and axial components of the magnetic flux are taken into account. The results obtained make it possible to clearly observe, as a function of the intensity of the bus current or the remanent induction, the saturation zones, the lines, the orientations and the magnetic flux densities. 3D finite element modelling provide more accurate numerical data on the magnetic field through multiphysics analysis. This analysis considers the actual operating conditions and leads to the design of an optimized machine structure, with or without current in the windings and/or permanent magnet.

ROBUST ADAPTIVE CONTROL SCHEME FOR IMPROVING LOW-SPEED PROFILE TRACKING PERFORMANCE OF HYBRID STEPPING MOTOR SERVO DRIVE

A robust adaptive control approach is presented to improve the performance of the control scheme proposed in the authors＇ previous work, aiming at producing a low ripple hybrid stepping motor servo drive for precision profile tracking at a low speed. In order to construct a completely integrated control design philosophy to reduce torque ripple and at the same time to enhance tracking performance, the properties of nonlinear uncertainties in the system dynamics are uncovered, and then incorporated into the design of the controller. The system uncertainties concerned with ripple dynamics and other external disturbances are composed of two categories. The first category of uncertainties with linear parameterization arising from the detention effect is dealt with by the wellknown adaptive control method. A robust adaptive method is used to deal with the second category of uncertainties resulting from the non-sinusoidal flux distribution. The μ-modification scheme is used to cease parameter adaptation by the robust adaptive control law, thus ensuring that the trajectory tracking error asymptotically converges to a pre-specified boundary. Experiments are performed with a typical hybrid stepping motor to test its profile tracking accuracy. Results confirm the proposed control scheme.

Linear Piezoelectric Stepping Motor with Broad Operating Frequency

The existing resonant linear piezoelectric motors must operate with high working voltage in resonant condition,resulting in their narrow operating frequency range and poor running stability.Here,with the large displacement output characteristics of piezoelectric stacks,the trajectory at the drive foot of stator is firstly produced with two space quadrature piezoelectric actuators excited by sawtooth wave and square wave.Secondly,the friction drive principle of motor is used to analyze the working mechanisms of the continuous stepping motion.Finally,the motor prototype is designed and experiments are carried out.The experimental result shows that the motor can stably operate within the scope of 350 Hz to 750 Hz.When the excitation voltage is 30 Vand pre-load is 3Nor10 N,the lateral amplitude of the drive foot is approximately 4μm and the stable average interval ranges from3.1μm to 3.2μm with the error rate of 5%—7.5%.

Fault-Tolerant Operation of Five-Phase Permanent Magnet Synchronous Motor with Independent Phase Driving Control

The multi-phase motor drive system with multiple H-bridge power supply has high fault tolerance,which is widely used in aerospace,electric vehicle,ship integrated power system and other fields.In this paper,a fault-tolerant control strategy based on decoupling control and stator current compensation is proposed for the propulsion system of five-phase PMSM with independent neutrals.Firstly,the mathematical model of PMSM is established by using vector space decoupling method;Secondly,a stator current compensation method is adopted to carry out fault-tolerant control after the motor has single-phase and two-phase open-circuit faults and the fault-tolerant control system based on decoupling control is established;Finally,the decoupling control model and the fault-tolerant control of stator current compensation are verified by the simulation and experiment.The simulation and experiment results show that the method can reduce the torque ripple caused by the stator winding open-circuit fault,and the operation performance of the motor under fault condition is significantly improved.

Encoderless Five-phase PMa-SynRM Drive System Based on Robust Torque-speed Estimator with Super-twisting Sliding Mode Control

In this paper,a robust torque speed estimator(RTSE)for linear parameter changing(LPC)system is proposed and designed for an encoderless five-phase permanent magnet assisted synchronous reluctance motor(5-phase PMa-SynRM).This estimator is utilized for estimating the rotor speed and the load torque as well as can solve the speed sensor fault problem,as the feedback speed information is obtained directly from the virtual sensor.In addition,this technique is able to enhance the 5-phase PMa-SynRM performance by estimating the load torque for the real time compensation.The stability analysis of the proposed estimator is performed via Schur complement along with Lyapunov analysis.Furthermore,for improving the 5-phase PMa-SynRM performance,five super-twisting sliding mode controllers(ST-SMCs)are employed with providing a robust response without the impacts of high chattering problem.A super-twisting sliding mode speed controller(ST-SMSC)is employed for controlling the PMa-SynRM rotor speed,and four super-twisting sliding mode current controllers(ST-SMCCs)are employed for controlling the 5-phase PMa-SynRM currents.The stability analysis and the experimental results indicate the effectiveness along with feasibility of the proposed RTSE and the ST-SMSC with ST-SMCCs approach for a 750-W 5-phase PMa-SynRM under load disturbance,parameters variations,single open-phase fault,and adjacent two-phase open circuit fault conditions.

MINIMUN TIME OPTIMAL CONTROL OF STEPPING MOTOR

The paper describes a new method of the stepping motor moimun time optimal control with closed-loop control. A mathematical model and optimal control strategy for the optimal control of stepping motor are proposed. Realizing technology for accelerating

Static-torque Characteristics of Three-phase Hybrid(HB) Stepping Motors and Influence of Way of Winding Connection on Operating Characteristics of Motors of This Kind

The paper presents the static-torque characteristics of three-phase hybrid stepping motors and discusses the influence of way of winding connection on operating characteristics of motors of this kind.

Numerical Modeling of the Coupled Electromagnetic and Mechanical Phenomena of Linear Stepping Motors

In this paper, we propose an electromagnetic-mechanical model based on the finite element and Macro-Element (ME) technique to analyse and study the dynamic characteristics of a Tubular Linear Switched Reluctance Stepping Motor (LSRSM). After the resolution of the non-linear electromagnetic equation governing the behaviour of the different materials of the motor using the nodal-based finite element method, this equation is then coupled to the mechanical equation firstly through the magnetic force computed by Maxwell stress tensor, and secondly by the modified flux distribution due to the moving part. Because of the precision required in the mobile part displacement and the very small air gap of stepping motors, the simulation of the movement is assured by the Macro-Element (ME) technique compared to other movement techniques that present many disadvantages. The validity of the developed model is verified through the comparison of the computed displacement of the LSRSM moving part with those given experimentally [2]. The Results shows satisfactory agreement. The obtained dynamic characteristics, particularly the starting magnetic force, are obtained by considering two values of the supplying currents.

A hybrid stepping motor system with dual CPU

An indirect method of measuring the rotor position based on the magnetic reluctance variation is presented in the paper. A single-chip microprocessor 80C196KC is utilized to compensate the phase shift produced by the process of position signals. At the same time, a DSP (Data Signal Processor) unit is used to realize the speed and current closed-loops of the hybrid stepping motor system. At last, experimental results show the control system has excellent static and dynamic characteristics.

Speed sensorless FCS-MPTC based on FOSM-MRAS five-phase permanent magnet synchronous motor

For the two-level five-phase permanent magnet synchronous motor(FP-PMSM)drive system,an improved finite-control-set model predictive torque control(MPTC)strategy is adopted to reduce torque ripple and improve the control performance of the system.The mathematical model of model reference adaptive system(MRAS)of FP-PMSM is derived and a method based on fractional order sliding mode(FOSM)is proposed to construct the model reference adaptive system(FOSMMRAS)to improve the motor speed estimation accuracy and eliminate the sliding mode integral saturation effect.The simulation results show that the FP-PMSM speed sensorless FCS-MPTC system based on FOSM-MRAS has strong robustness,good dynamic performance and static performance,and high reliability.

Analysis of Direct Torque Control for Marine Five-Phase Induction Motor

Based on the principle of direct torque control,a DTC(Direct Torque Control)system with five-phase induction motor has been studied.Providing direct control of stator flux and electromagnetic torque by optimized voltage vector,five-phase induction motor enhances flexibility of the invert states selection by increasing the number of voltage vectors,resulting in more precise control of stator flux and electromagnetic torque.The model of DTC for five-phase induction motor is constructed on equations and the method of approximate circle of torque track is used to conduct the simulation analysis of the system.The simulation results demonstrate that the DTC for five-phase induction motor control has merits of little calculation compared with vector control,simple structure,fast response and greater dynamic performance.

Research on simulation system of virtual three-phase stepping motor

To change the current phenomenon of ＂Being an armchair strategist＂ in the research of a stepping motor, the virtual simu- lation system of stepping motor was developed using virtual reality technique. The basic principle of stepping motor was expounded. The development strategy of the simulation software is introduced. Some key problems and their solutions, including coordinate transformation of rotor and order of on-off electricity for stator, were put forward in system development. Finally, there are three virtual simulation examples of the on-off electricity way in this paper. This work provides a valuable auxiliary tool for the study of the stepping motor.

Development of an underactuated prosthetic hand with the step motor

We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.

Performance Analysis and Comparison of Two Fault-Tolerant Model Predictive Control Methods for Five-Phase PMSM Drives

Model predictive current control(MPCC)and model predictive torque control(MPTC)are two derivatives of model predictive control.These two control methods have demonstrated their strengths in the fault-tolerant control of multiphase motor drives.To explore the inherent link,the pros and cons of two strategies,the performance analysis and comparative investigation of MPCC and MPTC are conducted through a five-phase permanent magnet synchronous motor with open-phase fault.In MPCC,the currents of fundamental and harmonic subspaces are simultaneously employed and constrained for a combined regulation of the open-circuit fault drive.In MPTC,apart from the torque and the stator flux related to fundamental subspace,the x-y currents are also considered and predicted to achieve the control of harmonic subspace.The principles of two methods are demonstrated in detail and the link is explored in terms of the cost function.Besides,the performance by two methods is experimentally assessed in terms of steady-state,transition,and dynamic tests.Finally,the advantages and disadvantages of each method are concluded.

Detection of rotor position by harmonic back EMF of hybrid step motor

The magnhc network model of a hybrid step motor is established by the air gap rate permeance method,and the expression of harmonic back EMF is deduced, and from the analysis above, a vovel use of harmonic backEMF sed to extract rotor peition is proposed and a new position sensor integral with the motoris designed .Experi-ments verified the correctness of the theorecal analysis. Ths type of rotor position sensor lays a foundation for closed-loop conrol of step motor.

Six-step Voltage Control of PM Brushless AC Motors under High Speed Flux-weakening Operation for EV/HEV Applications

The torque-speed characteristics of brushless motor having an interior permanent magnet rotor and a sinusoidal back-emf waveform are compared experimentally when it is operated in brushless AC(BLAC) mode and brushless DC (BLDC) modes with both 2-phase,120° conduction(BLDC-120) and 3-phase,180° conduction(BLDC-180).Particular emphasis is on high-speed,six-step voltage controlled,flux-weakening operation.It is shown that for EV/HEV applications,even for interior PM brushless motors which have sinusoidal back-emf waveforms,in order to achieve maximum torque per ampere capability over wide operation speed range,it is advantageous to employ a hybrid operation mode-BLAC operation in the constant torque region and six-step voltage control(BLDC-180 operation,together with current phase control) in the flux-weakening region.

An Experimental Investigation on the Dynamic Behavior of Step Motor Drives

Step motors, compared to other drive systems, are low-cost and easy to use devices. However, despite these undeniable advantages, they are characterized by some critical running conditions, due to the loss of synchronization between the stator＇s magnetic field and the rotor. In order to theoretically investigate such a behavior, several complex mathematical models have been developed, which require several parameters to be defined. For most step motors, such parameters cannot be easily drawn from their data-sheets; on the contrary, in this paper the authors refer to a simplified electro-mechanical model where the most of the parameters are known from data-sheets. The dependence between electrical and mechanical quantities can be investigated by an experimental point of view. At this aim, a specific novel test rig has been designed and developed for either static or dynamic characteristics measurement of small size step motors. In particular, the test rig allow to measure rotor＇s angular position, motor＇s torque, currents flowing in the motor＇s phases. The paper ends with the report of the results of several experimental tests, carried-out on a small-size motor in different running conditions, and with some preliminary remarks on the basis of the measures analysis.

A Step Motor Driver For the Let-off Mechanism of Looms

It is simple with good quality,and versatile with low costto use a step motor drive for the let-off mechanism ofweaving machines.This paper deals with the investiga-tion of this mechanism about the warp tension detectingand the design of the step motor drive system,which ispracticable,reliable and with low power consumption.So it is worthwhile to spread and push forward its appli-cation.

两相式混合步进电机速度和位移控制案例设计

步进电机在电脉冲信号的控制下能实现一定的角位移或线位移,掌握步进电机的控制技术非常重要。以两相混合式步进电机为控制对象,以单片机AT89C52和可编程计数器/定时器8253为主对电机进行速度和位移控制设计,对某一具体案例采用Proteus软件进行设计与仿真,包括控制电路和程序的设计。仿真和实验结果表明:该系统结构简单、容易实现、成本低,可用于其他步进电机的控制,并为教学或工程应用提供了参考。

带LC滤波器的永磁同步电机多步模型预测电流控制

【目的】为提升永磁同步电机(PMSM)模型预测电流控制(MPCC)的控制性能,在PMSM与逆变器之间增加LC滤波器。【方法】建立带LC滤波器的三阶多步MPCC系统,对逆变器电流、电容电压及电机电流进行预测控制,并与一阶多步MPCC和磁场定向控制(FOC)进行仿真对比。【结果】仿真结果表明:在相同开关频率和预测步数下,相较于一阶MPCC,三阶MPCC下PMSM的转矩脉动和电流脉动明显减小,电流总谐波失真(THD)更低;对于三阶MPCC,随着预测步数的增加,电流THD、电流脉动和转矩脉动逐步减小。【结论】随着预测步数的增加,三阶MPCC系统的控制性能逐步提升;三阶MPCC的控制性能优于一阶MPCC;在较高开关频率处,四步至五步的三阶MPCC的控制性能优于FOC。