• 제목/요약/키워드: Drive strategy

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A Novel High-Performance Strategy for A Sensorless AC Motor Drive

  • Lee, Dong-Hee;Kwon, Young-Ahn
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.2B no.3
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    • pp.81-89
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    • 2002
  • The sensorless AC motor drive is a popular topic of study due to the cost and reliability of speed and position sensors. Most sensorless algorithms are based on the mathematical modeling of motors including electrical variables such as phase current and voltage. Therefore, the accuracy of such variables largely affects the performance of the sensorless AC motor drive. However, the output voltage of the SVPWM-VSI, which is widely used in sensorless AC motor drives, has considerable errors. In particular, the SVPWM-VSI is error-prone in the low speed range because the constant DC link voltage causes poor resolution in a low output voltage command and the output voltage is distorted due to dead time and voltage drop. This paper investigates a novel high-performance strategy for overcoming these problems in a sensorless ac motor drive. In this paper, a variation of the DC link voltage and a direct compensation for dead time and voltage drop are proposed. The variable DC link voltage leads to an improved resolution of the inverter output voltage, especially in the motor's low speed range. The direct compensation for dead time and voltage drop directly calculates the duration of the switching voltage vector without the modification of the reference voltage and needs no additional circuits. In addition, the proposed strategy reduces a current ripple, which deteriorates the accuracy of a monitored current and causes torque ripple and additional loss. Simulation and experimentation have been performed to verify the proposed strategy.

The Study on Optimal PWM for 3 Phase Induction Motor Drive (3상 유도전동기의 운전을 위한 Optimal PWM에 관한 연구)

  • 이윤종;서기영;정동화
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.9
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    • pp.368-375
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    • 1985
  • This paper describes the OPTIMAL PWM strategy to reduce harmonic losses for a variaboe-speed drive of an induction motor. This OPTIMAL theory is the strategy which can reduce motor losses by defining harmonic losses as a performance index and achieving it's minimization. This PWM strategy is compared with the conventional NATURAL PWM technique by a numerical method, and verified the validity of numerical method by a result of implementing in a practical 1 Hp-3 Phase induction motor drive system. Also, we could achieve a maximum efficiency to drive an induction motor by selecting appropriately one alternative between OPTIMAL and NATURAL PWM techniques, and employing it in a full driving range.

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Impoved Performance of Sensorless Induction Motor Drive in Low Speed Range Using Variable Link Voltage (가변 링크전압에 의한 센서리스 유도전동기의 저속운전 성능개선)

  • 김상균;권영안
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.2
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    • pp.90-98
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    • 2004
  • Variable-speed drives are being continually innovated. Recently, sensorless induction motor drives have been much studied due to several advantages. Most sensorless algorithms are based on the mathematical modeling of motors, and all the information is obtained from the monitored voltages and currents. Therefore, the accuracy of such variables largely affects the performance of a sensorless induction motor drive. However, the output voltage of the SVPWM-VSI which is widely used in a sensorless induction motor drive has a considerable error, especially in a low speed range. This paper proposes a variation of the dc link voltage as a high-performance strategy for overcoming the above problem. The proposed strategy leads to an improved resolution of the output voltage of the SVPWM-VSI in a sensorless induction motor drive. Simulation and experiment have been performed for the verification of the proposed strategy.

Design of Hybrid Type Levitation and Propulsion System for High-Speed Maglev (초고속 자기부상열차를 위한 하이브리드형 부상 추진 시스템 설계)

  • Cho, Han-Wook;Han, Hyung-Suk;Lee, Jong-Min;Kim, Bong-Sup;Rho, Kyu-Suk;Kim, Dong-Sung
    • Proceedings of the KIEE Conference
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    • 2009.04b
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    • pp.94-96
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    • 2009
  • This paper deals with the design considerations of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several design considerations such as machine structure, manufacturing, and control strategy are described. In order to verify the design scheme and feasibility of control strategy, dynamic test set is implemented and tested.

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Voltage Control Strategy for Maximum Torque Operation of Stator-Flux-Oriented Induction Machine Drive in the Field-Weakening Region (약계자 영역에서 유도 전동기의 고정자 자속 기준 최대 토크 운전을 위한 전압 제어 기법)

  • Kim, H.J.;Yu, J.S.;Won, C.Y.;Kim, E.J.;Jo, H.K.;Kim, S.H.
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.30-32
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    • 2005
  • In this paper, voltage control strategy for maximum torque operation of stator flux-oriented induction machine drive in the field-weakening region is proposed. In a conventional stator flux-oriented (SFO) induction machine drive system of the maximum torque capability cannot be obtained. The field-weakening method is used to vary the stator-flux reference in proportion to the inverse of the rotor speed. The proposed algorithm, based on the voltage control strategy, ensures the maximum torque operation over the field-weakening region. The proposed algorithm, voltage control strategy for maximum torque operation of capability, which is insensitive to the variation of machine parameters In the field-weakening region. The proposed algorithm is verified by simulation.

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A New Overmodulation Strategy for Traction Dirve. (견인용 인버터를 위한 새로운 과변조 기법)

  • 배본호;설승기;김상훈;이인석;한성수
    • Proceedings of the KSR Conference
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    • 1998.11a
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    • pp.171-178
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    • 1998
  • This paper proposes a new overmodulation strategy to give a better voltage utilization by tracking voltage vector along hexagon sides. This strategy enables the inverter to control both magnitude and angle of current. Therefore, the vector control using this strategy can lead to better output torque dynamics compared to the conventional slip frequency control with six-step voltage, which is widely used in the traction drive. In this strategy, the d-axis output voltage of a current controller to control the flux is conserved and the q-axis output voltage to control the torque is controlled to place the voltage vector on the hexagon boundary In case of overmodulation. The limited q-axis voltage is used for anti-windup of q-axis current controller. This paper also presents a new field weakening scheme which incorporate the proposed overmodulation strategy. In this scheme, the flux level is selected by both required current limit and the available maximum voltage along hexagon sides. The validity of the proposed overall scheme is confirmed by the computer simulations for a typical traction drive with a 210[㎾] induction motor.

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New Overmodulation strategy for Propulsion system of the Light Rail Transit (경량전철용 추진제어장치의 새로운 과변조 기법)

  • Lee, Eun-Kyu;Choi, Jae-Ho
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.194-199
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    • 2003
  • The traction drive system for the urban transit Rubber-tire system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the Proposed traction drive system is verified by the MATLAB simulation results.

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New control strategy of propulsion system for the Transit Maglev System (자기부상열차용 추진제어장치의 새로운 제어기법)

  • 이은규;최재호
    • Journal of the Korean Society for Railway
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    • v.5 no.4
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    • pp.267-275
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    • 2002
  • The traction drive system for the urban transit maglev system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the proposed traction drive system is verified by the MATLAB simulation results.

Back ground and frontier on Matrix Converter (PWM Cyclo-Converter) for new drive system in next generation

  • Koga, Takashi;Lee, Hyun-Woo
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.200-207
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    • 2003
  • Today we have excellent motor drive system using high frequency carrier PWM control voltage source inverter with vector control strategy. In the other hand, we have met serious problems caused by high frequency switching. PWM Cyclo-converter called Matrix converter is expected as the new strategy possible to improve these problems and add some more convenient features suitable for new drive system with system integration. In this paper, we will introduce the background of this development and features of this converter from our research, additionally introduce remarkable active promotions for this converter as a survey.

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Back Ground and Expectation for Matrix Converter (PWM Cyclo-Converter) as New Drive System in Next Generation

  • Koga Takashi;Lee Hyun-Woo
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.216-222
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    • 2003
  • Today we have excellent motor drive system using high frequency carrier PWM control voltage source inverter in the other hand, we have met serious problems caused by high frequency switching. PWM Cyclo-converter called Matrix converter is expected as the new strategy Possible to improve these problems and add some more convenient features suitable for new drive system. in this Paper, we will introduce the background, features and outline of this converter, and additionally introduce some remarkable activity on this converter

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