• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.179-184
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• 2008

This paper presents the design of the feed forward controller to improve on the non-interference control performance of a single PWM converter in parallel for high-speed trains. The feed forward controller is designed to minimize the interference generated by converter switching in parallel operation of PWM converters. The gain value of the feed forward controller is calculated by inductance values of the input transformer. However, it is difficult to decide this gain value exactly because inductance values are changed by the operation condition of an input transformer. In this paper, the proposed design of feed forward controller can exactly decide the gain value using the leakage inductances estimated by detecting the variation of input current. the validity of the proposed feed forward controller is proved through the simulation results.

• 전력전자학회논문지
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• 제7권5호
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• pp.413-418
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• 2002

본 연구는 관성의 변화에 견실한 피드포워드 적응 위치제어기를 제안한다. 제안된 피드포워드 적응 위치제어기는 PI 위치제어기에 피드포워드와 기준모델 적응제어기를 추가한 구조를 가진다. 제어기의 특징은 과도상태에서 적응제어기가 위치오차와 기준모델의 속도 정보를 이용하여 피드포워드 이득을 조정한다. 이것은 과도응답 특성을 향상시키고, 정상상태의 수렴 시간을 개선시킨다. 위치 오차에 속도의 정보를 받아들여 기존의 Pl 위치제어 및 기준모델 적응제어에 비하여 속응성이 우수하다. 그리고, 적응제어기에 규준화 함수를 사용하여 입력크기에 대해 출력신호가 일정한 응답특성을 가지도록 하였다. 시뮬레이션을 통하여 제안된 피드포워드 적응 위치제어기 동작의 타당성을 보였다.

• 전력전자학회논문지
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• 제27권5호
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• pp.367-375
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• 2022

Generally, a proportional-resonant controller is used to eliminate steady-state errors during the voltage-current control of a double-conversion uninterruptible power supply (UPS) in a stationary reference frame. Additionally, the feed-forward control compensating for the load current, which can be considered a disturbance of the voltage controller, can be used to improve the disturbance rejection performance. However, during the parallel operation of UPSs, circulating current can occur between UPS modules when performing both feed-forward control and droop control because feed-forward control reduces the circulating current impedance. This study proposes a feed-forward compensation technique that considers the impedance of circulating current. An additional feed-forward compensation technique is developed to enhance the disturbance rejection performance. The validity of the proposed feed-forward compensation technique is verified by the experiment results of the parallel operation of a 500 W double-conversion UPS module.

• Journal of Power Electronics
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• 제11권2호
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• pp.140-147
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• 2011

In this paper, a novel position controller based on state feedback and feed-forward is proposed. Traditional position and speed controllers are replaced by a single controller with the position and speed as state feedbacks, and the position command and load torque as feed-forwards. The feedback and feed-forward gains are obtained by analytic modeling and design. The load torque, rotor speed and position are estimated by an observer based on a Kalman filter (KF) with a low resolution mechanical position sensor. Feed-forward compensation by an estimated load torque is used to improve the dynamic performance during load torque changes.

• 전기학회논문지
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• 제60권5호
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• pp.1011-1016
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• 2011

This paper presents a robust current controller for a surface-mounted permanent magnet synchronous motor(SPMSM) by using a PI observer. The decoupling PI(proportional-integral) controller combined with an additional feed-forward compensation has been used for the current controller. The classical feed-forward compensation using velocity information and system parameters is not expected to achieve a robust performance against parameter uncertainties. This paper has adopted a PI observer for the feed-forward compensation to cope with parameter uncertainties without using velocity information. A simple PI observer has been designed to compensate the disturbances that represent velocity coupled terms and parameter uncertainties. Experimental results as well as computer simulations with 630W SPMSM confirm that the proposed approach can deal with the effects of the disturbance and improve the control performance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.63-64
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• 2012

• Journal of Power Electronics
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• 제13권3호
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• pp.400-408
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• 2013

This paper presents a discrete state-space controller using state feedback control and feed-forward decoupling to provide a desirable control bandwidth and control stability for dynamic voltage restorers (DVR). The paper initially discusses three typical applications of a DVR. The load-side capacitor DVR topology is preferred because of its better filtering capability. The proposed DVR controller offers almost full controllability because of the multi-feedback of state variables, including one-beat delay feedback. Feed-forward decoupling is usually employed to prevent disturbances of the load current and source voltage. Directly obtaining the feed-forward paths of the load current and source voltage in the discrete domain is a complicated process. Fortunately, the full feed-forward decoupling strategy can be easily applied to the discrete state-space controller by means of continuous transformation. Simulation and experimental results from a digital signal processor-based system are included to support theoretical analysis.

• Journal of Power Electronics
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• 제4권4호
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• pp.217-227
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• 2004

A robust controller that combines the merits of the feed-back, feed-forward and model-following control for induction motor drives utilizing field orientation control is designed in this paper. The proposed controller is a two-degrees-of­freedom (2DOF) integral plus proportional & rate feedback (I-PD) speed controller combined with a model-following (2DOF I-PD MFC) speed controller. A systematic mathematical procedure is derived to find the parameters of the 2DOF I-PD MFC speed controller according to certain specifications for the drive system. Initially, we start with the I-PD feed­back controller design, then we add the feed-forward controller. These two controllers combine to form the 2DOF I-PD speed controller. To realize high dynamic performance for disturbance rejection and set point tracking characterisitics, a MFC controller is designed and added to the 2DOF I-PD controller. This combination is called a 2DOF I-PD MFC speed controller. We then study the effect of the 2DOF I-PD MFC speed controller on the performance of the drive system under different operating conditions. A computer simulation is also run to demonstrate the effectiveness of the proposed controller. The results verify that the proposed 2DOF I-PD MFC controller is more accurate and more reliable in the presence of load disturbance and motor parameter variations than a 2DOF I-PD controller without a MFC. Also, the proposed controller grants rapid and accurate responses to the reference model, regardless of whether a load disturbance is imposed or the induction machine parameters vary.

• 전력전자학회논문지
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• 제15권3호
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• pp.226-234
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• 2010

본 논문은 실제적인 변압기 운전환경에서 변화하는 승압형 인덕턴스를 실시간으로 추정하여 그 값을 통해 이득값을 계산하는 전향제어기를 제안하였다. 승압형 인덕턴스는 입력 전류의 변화분과 입력 교류 전압의 측정치만을 이용하여 추정되고, 그 값은 최소자승법을 적용하여 최적화 된다. 제안된 전향제어기는 변압기 운전 환경의 변화에도 강인한 제어가 가능하며, 입력 전류의 고조파 성분을 감소시켜 간섭현상에 따른 성능 저하를 최소화 할 수 있다. 제안된 기법의 타당성은 시뮬레이션과 실험 결과를 통해 검증하였다.

• Journal of Power Electronics
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• 제14권4호
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• pp.687-694
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• 2014

This paper focuses on the analysis and compensation of thrust ripples in permanent magnet linear synchronous motors (PMLSM). The main drawback in PMLSMs is the presence of thrust ripples, which are mainly due to the interaction between the permanent magnets and armature slotted core. These thrust ripples reduce the performance of the drive system in high precision applications especially at low speeds. This paper analyzes thrust ripples using the discrete wavelet transform. These undesired thrust ripples are compensated by using an adaptive feed forward controller. It is observed that this novel controller reduces about 65 percent of the thrust ripples. An extensive simulation is performed through MATLAB and it is validated through experimental results using a d-SPACE system with a DS1104 control board.