Single-phase Switched Reluctance Motor Research Articles

A Wireless-Driven, Micro, Axial-Flux, Single-Phase Switched Reluctance Motor

This study proposes a novel, axial-flux, single-phase switched reluctance motor for micro machines with wireless-driven capability. The rotor and stator each have two poles, and the stator utilizes two permanent magnets to provide the required parking position and rotational torque. By reducing the number of magnetic poles and coils in the stator, and by utilizing a cylindrical design for its stator components, the micro motor is able to be easily manufactured and assembled. Safety and convenience are also achieved through the use of a wireless drive, which negates the need for power connections or batteries. This study utilizes the topology method in rotor design to reduce excessive torque ripple. For this study, an actual micro, axial-flux, single-phase switched reluctance motor with a diameter of 5.5 mm and length of 4.4 mm was built in combination with a wireless charging module and motor circuitry found on the market. With an induced current of 0.7 A, the motor achieved a maximum of 900 rpm, indicating possible applications with respect to toys, micro-pumps, dosing pumps, and vessels for gases, liquids, or vacuum that do not require feedthrough.

A Modified Bridgeless Converter for SRM Drive with Reduced Ripple Current

<p>Single Phase Switched Reluctance Motor is more popular in many industrial purposes for high speed applications because of its robust and rugged construction. For low cost and variable speed drive applications SRM are widely used.Due to doubly salient structure of motor, the torque pulsations are high when compared to other sinusoidal machines. The major drawback in using SRM drive is torque pulsations and increased number of switching components. In order to overcome these drawbacks, a bridgeless Single Ended Primary Inductor Converter (SEPIC) is proposed. The major advantages of this converter are continuous output current,smaller voltage ripple and reduced semiconductor current stress when compared to the conventional SEPIC converter. The ripple free input current is obtained by using additional winding of input inductor and auxiliary capacitors. To achieve high efficiency, active power factor correction circuits (PFC) are employed to precise the power factor. Further, the unity power factor can be obtained by making the input current during switching period proportional to the input voltage is proposed. The proposed system consists of reduced components and it is also capable of reducing the conduction losses. The working principles and the waveforms of proposed converter are analyzed. To analyze the circuit operation, theoretical analysis and simulation results are provided. Finally, the comparison between the waveforms of conventional SEPIC and proposed system is presented by using MATLAB/Simulink tools.</p>

商用交流電源により直接駆動可能な単相SRMの提案と実機特性

This paper presents a novel single-phase switched reluctance motor (SRM) that can be directly driven by a commercial AC power supply without any switching circuit and sensor. This proposed SRM is optimized based on a simple design technique. The optimized machine has higher motor efficiency compared with conventional induction motors. In addition, the novel SRM can start-up with direct commercial AC power supply. In this paper, the performance of the prototype single-phase SRM is verified through simulations and experiments.

Acoustic Noise/Vibration Reduction of a Single-Phase SRM Using Skewed Stator and Rotor

This paper presents a single-phase switched reluctance motor (SRM) with skewed stator and rotor so that the acoustic noise and vibration have been significantly reduced. The motor has the same skew angle for both stator and rotor laminations. The main source of acoustic noise and vibration is the rapid change of radial magnetic force along the air gap between the stator and rotor poles. Since the radial force (RF) is most intensified on the stator yoke near the salient poles, the abrupt change of the RF can be mitigated by skewing the stator and/or rotor laminations. Therefore, the RF can be more distributed throughout the stator core, and in turn, the peak value of the RF is reduced. In this paper, the distribution of the RF with respect to the skew angles is analyzed through the finite-element method simulation to design a single-phase SRM with the significantly reduced vibration and noise. Based on the simulation results, prototype motors with three different skew angles (0°, 30°, and 64°) have been constructed and tested, validating that the proposed design is effective in mitigating acoustic noise and vibration.

기동 방법에 따른 단상 SRM의 토크 특성 해석

The single-phase switched reluctance motor(SRM) has only one inductance variation and the positive torque is generated in the restricted section. So, it cannot be started by itself. To solve this problem, many researchers have addressed the several starting method for the single-phase SRM.BR This paper is focused on the torque characteristics of the single-phase SRM according to starting method. The four major starting method - permanent magnet, saturable stator pole, to grade the rotor, stepped rotor pole - is selected to analyze the torque characteristics. The analysis model of each starting method is designed to changed the pole shape or inserting other material in the basic model. The torque characteristics of each analysis model is obtained by using FEM analysis. The FEM analysis is performed at incremental rotor positions over half inductance cycle in any one pole with 250AT, 500AT, 750AT. The distortion factor of each analysis model is analyzed through the FFT to compare the distortion between basic model and four analysis model.

Performance of Passive Boost Switched Reluctance Converter for Single-phase Switched Reluctance Motor

A novel passive boost power converter forsingle-phaseswitched reluctance motor is presented. A simple passive circuit is proposed comprisingthree diodes and one capacitor. The passive circuitis added in the front-end of a conventional asymmetric converter to obtain high negative bias. Based on this passive network, the terminal voltage of the converter side is a general DC-link voltage level in parallel mode up to a double DC-link voltage level in series mode. Thus,it can suppress the negative torque generation from the tail current and improve the output power. The results of the comparative simulation and experiments forthe conventional and proposed converter verify the performance of the proposed converter.

A New Low-Cost Hybrid Switched Reluctance Motor for Adjustable-Speed Pump Applications

This paper presents a new low-cost hybrid switched reluctance (HSR) motor intended for use in adjustable-speed pump drive systems. The motor is a single-phase motor, driven by a unipolar converter, which uses both the reluctance torque and the permanent magnet interaction torque. Compared with conventional single-phase switched reluctance motors, it has an increased torque density. The cogging torque is beneficially used in this motor for reducing the torque ripple. It is demonstrated that such a motor drive system can be a suitable candidate to advantageously compete with the existing motor drive systems for low-cost applications. Finite-element models are used to analyze and predict the motor's performance. The proposed motor drive system has been fabricated, and its performance has been tested in the laboratory. These experimental results are also presented.

회전자 형상을 고려한 단상 SRM의 특성 해석

단상 스위치드 릴럭턴스 모터는 구조가 간단하고 견고하며 구동 및 제어장치를 간소화할 수 있어 경제적으로 산업분야 및 가전기기 분야에 사용할 수 있다. 특히 현재 많이 사용되고 있는 단상 유도전동기는 효율이 낮고 제어성이 떨어지기 때문에 이를 대체할 수 있는 전동기로 단상 SRM이 제시되고 있다. 본 논문에서는 일반적인 전동기 설계와 다상 SRM 설계를 기반으로 회전자 형상에 따른 단상 SRM의 설계 및 특성을 제시하고자 한다. The single phase switched reluctance motor has simple, robust structure and economical drive system. So, it is useful to apply in the industrial and home applied machines. Especially, the single phase induction motor, used much in field, has a low efficiency and control ability. For the replacement of it, the single phase SRM is presented. In this paper, the design and characteristics of single phase SRM considering the rotor shape will be presented in the base of general electric motor design method and poly phase SRM design method.

단상 스위치드 릴럭턴스 모터에 설치된 영구자석 기동장치의 디텐트 토크

The single-phase switched reluctance motor(SRM) generates the positive torque in the restricted section. So, it can not started by itself and the torque ripple is heavier than poly-phase. For self-starting and fixing rotating direction, the rotor should be placed at the rising inductance slope when stationary. The parking permanent magnet locates the rotor in the fixed position, which can be started by it-self. It is very simple and cost effective but has some drawbacks. It affects the rotor during the operation, so the characteristics of motor, such as a torque, speed, and ripple are changed to go bad. This paper presents the detent torque of parking magnet starting device through the finite element analysis and experiments. The finite element analysis is performed at incremental rotor positions over one detent torque cycle for any one pole. The prototype, fabricated in the previous research, is used for the experiments. The inductance, instant torque, and detent torque are calculated using the terminal voltage and phase current. Finally, the finite element analysis result and the experiment result are compared for analysis and validity.

Harmonic Intensity Reduction Technique for Single Phase Switched Reluctance Motor Drives Using a New Random PWM Scheme

This paper proposes a new random switching strategy using a DSP TMS320F2812 to reduce the harmonics spectra of single phase switched reluctance motors. The proposed method combines the random turn-on/off angle technique and the random pulse width modulation technique. A harmonic spread factor (HSF) is used to evaluate the random modulation scheme. In order to confirm the effectiveness of the proposed method an experiment was conducted. The experimental results show that the harmonic intensity of the output voltage for the proposed method is better than that for conventional methods.

Approximate optimization for maximum efficiency of high speed single phase switched reluctance motor using response surface modelling

This paper presents an approximate optimization to maximize efficiency and power factor of high speed Single Phase Switched Reluctance Motor (SPSRM) in vacuum cleaner. Moreover, an optimum design process for SPSRM has been performed with geometric and electric parameters by using Response Surface Methodology and 2-D Finite Element Method that is coupled with the circuit equation of the rectifier and converter. To confirm the propriety of the Finite Element Method and the motor performance, simulation waveforms and experiment waveforms for motor voltage and current were compared.

저토크리플 및 역률개선을 위한 수정된 단상 SRM 구동시스템

The single-phase switched reluctance motor(SRM) drive requires DC source which is generally supplied through a rectifier connected with a commercial source. The rectifier is consist of a diode full bridge and a filter circuit. Usually the filter circuit uses capacitor with large value capacitance to reduce ripple component of DC power. Although the peak torque ripple of SRM is small, the short charge and discharge current of the filter capacitor draws the low power factor and system efficiency. A modified single phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor. In the proposed drive circuit, one switching part and diode which can separate the output of AC/DC rectifier from the filter capacitor is added. Also, a upper switch of drive circuit is exchanged a diode in order to reduce power switching device. Therefore the number of power switch device is not changed, two diodes are only added in the SRM drive. To verify the proposed system, some simulation and experimental results are presented.

Converter Coupled Finite Element Analysis of Single Phase Switched Reluctance Motor

This paper deals with the characteristic analysis of the single phase switched reluctance motor based on the converter coupled FE analysis. The converter comprises a rectifier, LC filter and switching power device. A computational technique for the converter coupled FE analysis is introduced and its validity is proven by the experiment.

Design of the Starting Device Installed in the Single-Phase Switched Reluctance Motor

The single-phase switched reluctance motor (SRM) generates the positive torque in the restricted section. It cannot start by itself and the torque ripple is heavier than multiphase SRM as the positive torque is not generated in all the sections. For self-starting and fixing rotating direction, the rotor should be placed at the rising inductance slope when stationary. This paper proposes the design process of the starting device which puts the rotor in the starting position before it is started and design the starting device composed of the parking permanent magnet for the prototype single-phase SRM. The equation of the magnetic attractive force required at the acting point is derived from the equation of rotational motion and calculated by the experiment with the prototype. Finally, the proper position and magnetic attractive force of the permanent magnet as well as the starting torque is confirmed through the FEM analysis

Single-Phase SRM Drive With Torque Ripple Reduction and Power Factor Correction

In a single-phase switched reluctance motor (SRM) drive, the dc voltage source is generally supplied by a circuit consisting of a bridge rectifier and a filter capacitor connected to an ac line. The charging time of the capacitor is shorter from the ac source as capacity increases. The bridge rectifier draws pulsating current from the ac source, which results in a degraded power factor (PF) and lower system efficiency. A single-phase SRM drive system is presented in this paper, which includes the realization of a drive circuit for the reduction of torque ripple and PF improvement with a novel switching topology. The proposed drive circuit adds one switch and one diode, which can separate the output of the ac/dc rectifier from the large capacitor and supply power to the SRM alternately. This allows the drive system to realize torque ripple reduction and PF improvement through the switching scheme. The validity of the proposed method is analyzed by mathematical modeling and tested by simulations and experiments.

Starting the Single-Phase Switched Reluctance Motor Using Rotor Shorting Rings

This article presents a technique that uses rotor shorting rings to start the single-phase switched reluctance (SR) machine, from any rotor position, in a specified direction. It also outlines how the shorting rings enable starting of the machine. Transient finite-element analysis is used to illustrate the torque-producing mechanism from the aligned position using the rotor-mounted shorting rings. It is also used to determine the optimal stator and rotor pole arcs and shorting ring design for a 200-W prototype machine. An SR drive system incorporating rotor shorting rings is evaluated, and experimental results show the effectiveness of the technique

The high-speed operation of single phase switched reluctance motor considering magnetic saturation

In the high-speed operation of SRM, the conventional pulse width modulation (PWM) drive method is not available because of the limitation of switching speed; therefore the single-pulse drive method is commonly employed. On the contrary, the use of the single-pulse drive method cannot avoid the overcurrent in the low-speed operation because of the insufficient back emf and the difficulty of duty control. With these reasons, the switching method is commonly changed from PWM at the low-speed operation to the single-pulse method at the high-speed operation. In the fan application, the required load torque increases as a square of the fan speed; it requires more current for the torque generation. Therefore at the mode transition between PWM and single-pulse drive, it is unavoidable that the phase current rapidly increases if the nonlinearity of inductance to the current is not considered. In this paper, by using finite element method (FEM) which is considered with the nonlinearity of the inductance with respect to the current, the speed of mode transition is calculated (18 000 rpm) and verified by the experiment.

Evaluation of Rotor Conducting Screens on the Single-Phase Switched Reluctance Machine

The single-phase switched reluctance machine has a simple and robust construction and is suitable for high-speed operation. Torque production is a function of the difference between the aligned and unaligned inductance, and increasing this difference theoretically will increase the torque. In this article, conducting screens are incorporated into the rotor of a prototype 2/2 single-phase switched reluctance motor. The effect of the conducting screens on current response, flux linkage, and output torque is evaluated using finite element analysis and validated experimentally. At fixed current conduction angles, conducting screens improve the rate of change of inductance at low speed, and enhance performance at high speed when the machine operates in the single voltage pulse mode. The conducting screens have a negative effect on the output torque when using optimal commutation angles. Reasons for this phenomenon are given.

Energy efficiency for fractional power loads

The single-phase switched reluctance motor (SSRM) is presented as a robust and rather economic solution for fractional power-load applications where a low-starting torque is required. This work discusses the principle of operation of the SSRM, the prototype design, driving strategy for starting and steady state operation, modeling and simulation results, steady-state measurements, and performance comparisons with the conventional single-phase induction motor (SPIM). Simulation and experimental results are presented for a 4/4 SSRM prototype and associated electronic converter and found to be in good agreement. The results shown that under steady-state operation, the measured input power required by the SSRM is 37.5% smaller than that drawn by the SPIM to drive the load in similar conditions

Single-phase switched reluctance motor design

The evolution of a novel form of single-phase switched reluctance motor, suitable for example for high-speed fans is described. The motor has four stator and four rotor poles, but only two coils. The new motor is derived by simple analysis from the basic 2-pole machine using sweeping assumptions. It is predicted to have only half the core length, less copper loss, but significantly more iron loss than the 2-pole form. These conclusions are tested using computer-based analysis, and test results from a prototype motor are presented which confirm the attractiveness of the design. Attention then turns to the starting problem of all such machines, and a method using permanent magnets is shown to be particularly appropriate for the new motor. The operation of this method is analysed, and simulated starting responses are compared with experimental results.