Theory and operation of a four-quadrant switched reluctance motor drive with a single controllable switch-the lowest cost four-quadrant brushless motor drive

Low-cost motor drives are being sought for high-volume energy-efficient home appliances. Key to the realization of such low-cost motor drives is the reduction of the power electronic converter to the barest in terms of its components, particularly the active devices, finding the motor with the least complexity for manufacturing and a controller that can extract the desired performance from the machine and converter combination. These and other factors such as self-starting, speed control over a wide range, and, most of all, the crowning aspect of four-quadrant operation with a bare minimum number of controllable switches remain as formidable challenges for low-cost motor drive realization. An innovative four-quadrant switched reluctance motor (SRM) drive with only one controllable switch is realized in this paper, for the first time, in the opinion of the authors. The motor drive is realized using a two-phase machine and a single controllable switch converter. The theory and operation of the proposed four-quadrant SRM drive with the proposed control algorithm for its realization are described. The motor drive is modeled, simulated, and analyzed to verify its feasibility for self-starting, speed control, and for four-quadrant operation, and the simulation results are presented. Experimental results confirm the validity of the proposed control algorithm for four-quadrant control of the SRM drive. The focus of the paper is mainly directed toward the control algorithm for realizing the four-quadrant operation of the two-phase SRM drive with a single controllable switch converter.     

A Novel Self-Commutating Low-Speed Reluctance Motor for Direct-Drive Applications

This paper presents a novel low-speed and high-torque motor, self-commutating low-speed reluctance motor (SCLRM), for direct-drive applications. With six diodes connected to the stator windings, it is capable of self-commutating when working on normal three-phase ac source for constant-speed operation. It provides an uncomplicated and low-cost method to increase the torque capability of the traditional vernier-type motors without the requirement of permanent magnets and inverter drive. In this paper, the basic theory of SCLRM is presented, including the operation principle and the mathematical models from which the calculation equations of the inductance parameters as well as the electromagnetic torque are deduced. Besides, the simulation and implemental results are shown, and the reasons of the improvement of the torque capability are analyzed. Moreover, an inverter drive system for SCLRM whose topology is different from that of the standard three-phase inverter is proposed for variable-speed applications     

A unipolar converter for a switched reluctance motor

A switched reluctance motor requires a power converter circuit to control the unipolar phase current in its phase windings. A converter circuit for a four-phase reluctance motor that uses only four switches is described. Unlike previous circuits with one switch per phase, the switches are created at the motor voltage. Each switch is connected to two of the four phase windings. The switching signals must be carefully derived so that independent control of the phase currents is maintained despite the common connections. Analysis is given to predict the ideal switching algorithm for the converter circuit. This produces the optimum torque at all speeds and currents. Experimental results are given for the performance of the proposed converter circuit as compared with that of other circuits with one switch per phase. It can be seen that for a given supply voltage and peak phase current, the novel converter circuit produces superior torque output from the motor. The low number of switches in the coinverter together with the performance of the four-phase reluctance motor will result in an ideal low-cost variable-speed drive     

两相无轴承电机开关损耗抑制算法

针对全桥功率拓扑以及传统SVPWM驱动算法在两相无轴承电机控制中存在的问题,本文研究采用两相三桥臂功率拓扑方案配合开关损耗抑制算法实现两相无轴承电机的驱动控制。首先,理论推导两相三桥臂功率变换器SVPWM算法。其次,在两相三桥臂SVPWM算法基础上,提出适合于高载频控制条件下的开关损耗抑制算法。第三,从开关器件工作损耗及相电流谐波含量等方面对传统SVPWM算法和开关损耗抑制算法进行对比。最后,在一台两相无轴承电机实验平台上验证所提开关损耗抑制算法的有效性。     

基于RPWM的变频器降噪研究

本文针对变频器供电交流传动系统带来的噪声问题,提出了一种随机开关频率与空间电压矢量调制结合的新方法,即可变延迟开关周期PWM方法(VDRPWM),以实现开关频率随机化;并以某型电机的变频器为研究对象,设计了三相空间电压矢量控制的电机系统.并利用Matlab/Simulink对三相空间电压矢量控制电机系统进行了仿真,研究结果表明该方法能明显减弱系统的二次以及高次谐波,降低了系统的噪声.该方法实现简单,对于大容量电机具有一定的应用前景.     

Microcontroller based digitally controlled ultrasonic motor drive system

Piezoelectric driven ultrasonic motors have been attracted as considerable actuators for the servo speed and position applications in recent years. These motors have important features and advantages to be preferred in the special movement applications. Ultrasonic motors have different operating principles and different drive and control systems than the electromagnetic motors. In this study, microcontroller based digitally controlled drive system has been proposed for a travelling-wave ultrasonic motor. Drive system includes power circuit, interface electronics circuits and microcontroller parts. Power circuit is combined from half-bridge serial-resonance inverter to provide highfrequency two-phase voltages. Interface circuits include gate drive, direction control, opto-coupler and filter circuits. Microcontroller is programmed to generate required digital control signals for overall control of the motor. Related to the reference speed, the microcontroller generates control signal resulting proper driving frequency. Consequently, the actual motor speed tracks the reference speed precisely. The speed feedback is taken from optical encoder and transmitted to the controller as digital speed and position signals. The developed drive system has been tested experimentally. The obtained results show the effectiveness and reliability of the proposed system. The microcontroller based drive system can be applied easily and successfully to the ultrasonic motor.     

PM brushless DC motor drive with a new power-converter topology

With the growing potential for widespread use of permanent magnet brushless DC motor (PMBDC) drives in many low-cost applications, such as HVAC, refrigerators, and freezers in houses and small-velocity servos in process industries, it has become important to minimize the cost. One obvious place for cost reduction is in the cost of the inverter and its associated controller. With that perspective, a novel application of the converter topology for the PMBDC known as “C dump” in switched reluctance motor drives is proposed in this paper. The advantages and disadvantages of this topology vis-a-vis the conventional three-phase H-bridge converter, are highlighted from the points of view of economy in switches, volt-ampere rating, associated controller cost, and packaging. Design considerations for the PMBDC are derived for use with the proposed converter topology. The operational and design characteristics of this converter-driven PMBDC drive are derived for four-quadrant performance. Guidelines for the design of the proposed topology are derived, and presented in the paper. Experimental results from a laboratory prototype are presented to validate the feasibility of the proposed PMBDC drive system     

Sensorless Direct Field-Oriented Control of Three-Phase Induction Motor Drives for Low-Cost Applications

A sensorless direct rotor field-oriented control (SDRFOC) scheme of three-phase induction motors for low-cost applications is presented in this paper. The SDRFOC algorithm is based on a sensorless closed-loop rotor flux observer whose main advantages are simplicity and robustness to motor parameter detuning. The whole algorithm has been developed and implemented on a low-cost fixed-point digital signal processor controller. Experimental results are presented for a 0.5-kW induction motor drive for a primary vacuum pump used in industry applications.     

Flux-Switching Motors for Automotive Applications

This paper presents a new class of brushless motor as an alternative to the permanent-magnet brushed motor used in the automotive industry. The new flux-switching motor is a very simple motor to manufacture, and, coupled with a powerelectronic controller requiring only two power semiconductor switches, it has the potential to be extremely low cost in high volume applications. The design of the motor and its simulation using coupled circuit and time-stepping finite-element analysis is presented. Tested performance has matched well with design targets and with simulation and is delivering performance comparable to a permanent-magnet brushed motor. The new motor and drive are very robust, requiring only two power MOSFETS and a simple microcontroller to create an extremely low-cost variable-speed drive for automotive applications.     

Low-cost battery-powered switched reluctance drives with integral battery-charging capability

This paper presents a low-cost battery-powered drive using switched reluctance motors. The converter topology proposed in this paper is cost effective while still maintaining an energy-efficient system for battery-powered drives. The proposed drive not only achieves cost-effective and efficient battery motoring, but also battery charging with minimal additional power semiconductor components. Charging is achieved through the windings of the switched reluctance motor, thus eliminating the need of external bulky transformers and separate charging units.     

Dual AC-drive system with a reduced switch count

A dual current-regulated pulsewidth-modulated voltage-source inverter based on multiple two-phase PWM inverters, also called a B4 topology, requiring a dual AC-drive system with reduced switch count is proposed. The drive utilizes a total of only eight switches to produce two sets of three-phase or two-phase sinusoidal output currents that can be employed to feed three-phase or two-phase induction motors. A suitable control strategy of this new scheme is shown to minimize the single-phase current now through the DC-link capacitors, which is a common problem in reduced-switch-count topologies. In order to verify the performance of the motor drive system, an application on traction of an electric vehicle is carried out. Results show that the AC current through the DC link can be minimized, and when utilizing two-phase motors on the proposed dual drive, the reduced voltage gain problem, also common in B4 topologies feeding three-phase motors, can be solved     

永磁直线电机精确相变量建模方法

针对永磁直线电机控制系统的精确动态仿真,提出了一种基于有限元的永磁直线电机一般化相变量建模方法。考虑电机非理想结构对推力的影响,建立了永磁直线电机的一般化相变量模型。采用3次样条插值,根据电磁场有限元计算结果获得了模型中电感、齿槽力、永磁体产生的磁链与动子位置的关系曲线。考虑功率电子模块中吸收电路的影响,提出了一种基于S-function的仿真建模方法,根据相变量模型的状态方程直接建立了Simulink下的永磁直线电机一般化仿真模型。对某种永磁直线电机进行了两相导通控制和id=0矢量控制下的控制系统仿真实验,仿真结果表明,基于有限元的相变量模型为永磁直线电机控制系统精确动态分析提供了一种快速、有效的一般化建模方法。     

功率MOSFET变换器在开关磁阻电动机驱动系统中的应用

本文介绍了一种新型调速系统－开关磁阻电动机驱动系统，分析了驱动系统的特点及其对功率变换器的要求，并论述了在中小功率场合应用功率ＭＯＳＦＥＴ作为功率变换器的意义，同时对该系统的功率变换器器件设计、功率ＭＯＳＦＥＴ的栅极驱动与保护作了研究。     

Optimal Design of 1 Phase Linear Oscillatory PM Motor Series for Small Compressor Like Drives: With FEM and Self-Starting Transients Validation

Refrigerator compressors are currently driven mostly by rotary line start or variable-speed (inverter-fed) motors with mechanical transmission. Direct driving of pistons by linear oscillatory resonant PM 1 phase motors has just been introduced to low power (less than 100 W) such applications. The present paper introduces a 3 pole PM mover 1 phase PM linear oscillatory motors, in terms of optimal nonlinear analytical design methodology, with FEM and dynamics validation. Both 50 and 250 Hz (inverter fed) operation for 2000 and 100 W is exemplified for minimum active materials costs and, respectively, minimum global costs (losses capitalized cost is added). For the line start case study (at 2000 W, 50 Hz) a circuit model for transients is introduced and the motor self-starting transients with full power delivery at above 91% efficiency is available. The 50 Hz motors are heavier around (5.7 kg/kW at 2000 W and 7.5 kg/kW at 100 W, respectively) than the 250 Hz motors around (1.2 kg/kW, 3 kg/kW) but the latter require inverter control.     

Position control of the induction motor using a passivity-basedcontroller

Most position tracking applications employ either DC or permanent-magnet motors. In this paper, an induction motor drive for position control applications is proposed. Such a drive adopts a passivity-based controller which mainly differs from the others because its formulation emphasizes system energy properties and behavior. The controller has simple equations and good robustness without using complex flux observers and the exact knowledge of the motor parameters, as well. The proposed drive has been practically implemented, achieving satisfactory results     

Implementation of EKF based sensorless drive system using vector controlled PMSM fed by a matrix converter

A PMSM sensorless drive fed by a matrix converter has been designed to show that a drive system with high performance and efficiency can be constructed by combining the advantages of matrix converters, permanent magnet synchronous motors and sensorless control. Sensorless control of the motor is performed by using Extended Kalman Filter. The characteristics of matrix converter and performance of PMSM which are implemented by using a digital signal controller has been analyzed. Differences between the sensored and sensorless PMSM drive systems are also presented by considering the waveforms of the drive system. Promising results illustrated that EKF based sensorless control of matrix converter fed PMSM drive system with a good performance is achievable at medium and high speed operations.     

AC motor drive systems with a reduced-switch-count converter

This paper presents two reduced-switch-count AC drive systems. One of the configurations was conceived to operate with a two-phase motor and the other one with a three-phase motor. The drive systems provide both bidirectional power flow and power factor control. Pulsewidth modulation techniques for the converter control are discussed. Experimental results are presented.     

Integrated metering and protective relay systems

The process of converting sampled analog signals to digital numbers using a low-cost microprocessor and an A/D converter for motor protection is considered. Distribution fault records, relay performance with extremely saturated low ratio current transformers, and advanced methods of protecting high-inertia drive motors are presented. The discussion also covers: digital filtering; range of operation of a digital overcurrent relay; the function of the anti-aliasing filter; advances in motor protection; rotor thermal model; and maintainable structured software     

A novel position sensorless control scheme for doubly fedreluctance motor drives

A novel position sensorless control algorithm for the newly developed doubly fed reluctance motor (DFRM) drives is presented. The control makes use of the 60 Hz terminal variables, which are easy to acquire and process, for estimation and control of the torque angle of the machine, while the speed of the system is given in an open-loop mode. The control is robust and suitable for variable-speed pump-type application. With this control, the required VA ratings of the PWM converter are only 50% of that of the DFRM motor, and the motor can be started with full load torque. This control scheme has been successfully implemented on a 2-HP DFRM drive