• Title/Summary/Keyword: Low torque

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Design Techniques for Reducing Cogging Torque in Permanent Magnet Flux Switching Machine

  • Wang, Daohan;Wang, Xiuhe;Jung, Sang-Yong
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.361-364
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    • 2013
  • Permanent magnet flux switching motor (PMFSM) is a novel double salient machine which employs PMs instead of field winding for excitation. PMFSM contains only one set of armature winding, thereby features simple control strategy, low cost power inverter and substantial high efficiency. Due to the unique double salient structure and operation principle, the generated cogging torque in PMFSM is critical and quite different compared to the traditional PM machines. This paper presents and investigates various design techniques for reducing cogging torque in PMFSM. Firstly, an analytical model is proposed to study the influence of different methods on cogging torque. Then the optimal design parameters for minimizing cogging torque are determined by the analytical model, which significantly reduces the computational efforts. At last, the cogging torque with different design approaches are simulated by FEA along with the average output electromagnetic torque, which validates the analysis above.

Effects of blade configuration and solidity on starting torque of Darrieus wind turbine

  • Roh, Sung-Cheoul;Kang, Seung-Hee
    • Wind and Structures
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    • v.32 no.2
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    • pp.169-177
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    • 2021
  • This study investigates the effects of blade configuration and solidity of Darrieus wind turbine on the starting torque characteristics. Generally, the configuration of Darrieus wind turbine is divided into Troposkien, parabola, Catenary, Sandia, modified-parabola and straight types. A numerical analysis has been carried out using Multiple Stream Tube (MST) method to investigate the effect of blade configuration and solidity of Darrieus wind turbine on the starting torque under the initial low range of rotational speed. The simulation results show that the starting torque of Darrieus wind turbine varies considerably depending on the blade configuration. The initial starting torque was larger with Troposkien, Parabola, Catenary, and Sandia configurations than with modified parabola or straight types. The increase in solidity with increasing number of blades raised the starting torque and improved the dynamic stability during the initial operational speed of Darrieus wind turbine. Additionally, these torque results represent basic data for fluid-structure interaction (FSI) simulation of the steady-dynamic operation of the turbine.

Low Parameter Sensitivity Deadbeat Direct Torque Control for Surface Mounted Permanent Magnet Synchronous Motors

  • Zhang, Xiao-Guang;Wang, Ke-Qin;Hou, Ben-Shuai
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1211-1222
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    • 2017
  • In order to decrease the parameter sensitivity of deadbeat direct torque control (DB-DTC), an improved deadbeat direct torque control method for surface mounted permanent-magnet synchronous motor (SPMSM) drives is proposed. First, the track errors of the stator flux and torque that are caused by model parameter mismatch are analyzed. Then a sliding mode observer is designed, which is able to predict the d-q axis currents of the next control period for one-step delay compensation, and to simultaneously estimate the model parameter disturbance. The estimated disturbance of this observer is used to estimate the stator resistance offline. Then the estimated resistance is required to update the designed sliding-mode observer, which can be used to estimate the inductance and permanent-magnetic flux linkage online. In addition, the flux and torque estimation of the next control period, which is unaffected by the model parameter disturbance, is achieved by using predictive d-q axis currents and estimated parameters. Hence, a low parameter sensitivity DB-DTC method is developed. Simulation and experimental results show the validity of the proposed direct control method.

Reduction of cogging torque of Servo motor with Rare earth Permanent Magnets & Its application (희토류 영구자석 서보모터의 코깅토오크 저감방법 및 시제품에의 적용)

  • Han, Moon-Kyu
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.128-130
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    • 1998
  • In a recent as the compact and the precision motor is needed, the use of rare earth permanent magnet with high energy product is frequent. Accordingly it is important to reduce the cogging torque for improving the control precision of motor. In order to develop the motor with low cogging torque which is contented with the requirement of customer, the prototype is designed and complete based on analysis method to reduce the cogging torque. The experimental results verify the validity.

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Preliminary Design Analysis of Low Speed Interior Permanent Magnet Machine with Distributed and Concentrated Windings

  • Ahsanullah, Kazi;Dutta, Rukmi;Rahman, M.F.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.2
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    • pp.139-147
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    • 2014
  • The paper presents a systematic comparison of four topologies of the interior permanent magnet machine (IPMM) designed for low speed applications. This comparative study investigates the suitability of the concentrated winding and distributed winding in the stator and the flat-shaped or V-shaped magnets in the rotor poles. The paper also studies the inductance characteristics of the designs using finite element analysis. Various steps taken to minimize the cogging torque and torque ripple in the studied machines were also discussed in details.

Characteristics of the Two-phase Induction Motor By the Inverter Fed Control

  • Yang Byoung-Yull;Kwon Byung-Il
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.4
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    • pp.312-316
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    • 2005
  • The single phase induction motor has been commonly applied to small-sized electrical appliances because of its low cost, but it has low efficiency and large torque ripple, and it is incapable of speed control. However, two-phase induction motors have small torque ripple, high efficiency and variable speed control, because they are inverter fed. In this paper, the dynamic characteristics of the two-phase induction motor, such as the torque ripple, current and speed, are analyzed by using the time-stepping finite element method, and compared with the cage-type single phase induction motor.

A Study on the Effect of Valve Timing on the Performance and Idle characteristics of 3-Cylinder LPG Engine (밸브 타이밍 변화가 3기통 LPG 엔진의 성능과 Idle 특성에 미치는 영향에 관한 연구)

  • 이지근;이한풍;노병준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.3
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    • pp.27-34
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    • 1997
  • The effects of the intake and exhaust valve timing to improve the engine performance in a spark ignition 3-cylinder LPG engine with a closed loop fuel supply system were studied. The engine torque and power have been measured using the 75kW EC-dynamometer while adjusting the optimal fuel consumption ratio with a solen- oid driver. As the results from this experiment, when intake valve opening is $12^{\circ}$ BTDC, intake valve closing is $36^{\circ}$ ABDC, exhaust valve opening is $12^{\circ}$ ATDC, and exhaust valve closing is $36^{\circ}$ BBDC respectively, the best torque characteristics in low and high speeds for a gives engine were obtained. And also we could find that the torque characteristics in low speeds were affected by the timing of exhaust valve open. An increased valve overlap by the EVC delay was ineffectual to the torque characte- ristics improvement in high speeds.

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Improvement of DITC SRM with a Novel 4-level Converter (4-레벨 컨버터 회로를 통한 SRM의 DITC 시스템의 성능향상)

  • Liang, Jianing;Lee, Zhen-Guo;Lee, Dong-Hee;Ahn, Jin-Woo
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.929-930
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    • 2006
  • This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Moto (SRM) with a novel 4-level converter to obtain smooth torque and dynamic performance improvement. The DITC method can reduce the high inherent torque ripple of SRM drive system, but driving efficiency and dynamic performance are somewhat low due to the slow excitation current build-up. Since the 4-level converter can obtain a addition high voltage to get fast excitation current and demagnetization current, so, it can improve dynamic performance easily. As a high performance SRM drive system with low torque ripple and high dynamic performance can be implemented. The validity of proposed method is verified by some computer simulations and comparative experiments.

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Feed-Forward Approach in Stator-Flux-Oriented Direct Torque Control of Induction Motor with Space Vector Pulse-Width Modulation

  • Kizilkaya, Muhterem Ozgur;Gulez, Kayhan
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.994-1003
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    • 2016
  • Two major obstacles in the utilization of electrical vehicles are their price and range. The collaboration of direct torque control (DTC) with induction motor (IM) is preferred for its low cost, easy implementation, and parameter independency. However, in terms of edges, the method has drawbacks, such as variable switching frequency and undesired current harmonic distortion. These drawbacks result in acoustic noise, reduced efficiency, and electromagnetic interference. A feed-forward approach for stator-flux-oriented DTC with space vector pulse-width modulation is presented in in this paper. The outcome of the proposed method is low current harmonic distortion with fixed switching frequency while preserving the torque performance and simple application feature of basic DTC. The method is applicable to existing and forthcoming IM drive systems via software adaptation. The validity of the proposed method is confirmed by simulation and experimental results.

Extending Switching Frequency for Torque Ripple Reduction Utilizing a Constant Frequency Torque Controller in DTC of Induction Motors

  • Jidin, Auzani;Idris, Nik Rumzi Nik;Yatim, Abdul Halim Mohd;Sutikno, Tole;Elbuluk, Malik E.
    • Journal of Power Electronics
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    • v.11 no.2
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    • pp.148-155
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    • 2011
  • Direct torque control(DTC) of induction machines is known to offer fast instantaneous torque and flux control with a simple control structure. However, this scheme has two major disadvantageous, namely, a variable inverter switching frequency and a high torque ripple. These problems occur due to the use of hysteresis comparators in conventional DTC schemes, particularly in controlling the output torque. This paper reviews the utilization of constant frequency torque controllers (CFTC) in DTC to solve these problems while retaining the simple control structure of DTC. Some extensions of the work in utilizing a CFTC will be carried out in this paper which can further reduce the torque ripple. This is particularly useful for a system which has a limited/low sampling frequency. The feasibility of a CFTC with an extended carrier frequency in minimizing the torque ripple is verified through experimental results.