• 전기전자학회논문지
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• 제24권4호
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• pp.1104-1108
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• 2020

본 논문에서는 3상 영구자석 동기전동기의 속도리플 저감을 위한 가변형 비례공진 전향보상 알고리즘을 제안한다. 일반적인 토크 맥동의 원인은 전류측정오차 및 데드타임으로 인한 전기적 맥동과 회전자 편심과 편심 부하로 인해 발생될 수 있다. 이러한 토크 맥동은 전동기의 속도 맥동을 야기하고 전동기 구동 시스템의 운전 성능을 저하시킬 수 있다. 이를 위한 본 논문에서는 속도 맥동의 원인을 분석하고 속도 맥동을 저감하기 위한 알고리즘을 제안하였다. 제안한 알고리즘은 속도 맥동에 포함된 특정 운전 주파수를 저감하기 위해 가변형 비례 공진 제어기를 적용하였고, 전향보상 제어기 구조를 이용하여 보상동작이 수행되도록 하였다. 제안한 알고리즘은 다양한 실험을 통하여 타당성과 효용성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1087-1089
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• 2003

This paper presents a method to reduce commutation torque ripple in a sensorless brushless DC motor drive without current sensors. To compensate the commutation torque ripple completely, the duration of commutation must be known. The proposed method measures the duration of commutation from terminal voltage waveforms, calculates a PWM duty ratio to suppress the commutation torque ripple from the output of speed controller, and applies the calculated PWM duty ratio only during the commutation. Experimental results show that vibrations are considerably reduced when the proposed method is applied to the sensorless brushless DC moter drive for air-conditioner compressor.

• 전력전자학회논문지
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• 제26권5호
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• pp.342-348
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• 2021

The PV module of solar power systems requires maximum power point tracking (MPPT) technique because the power-voltage and current-voltage characteristics vary depending on the surrounding environment. In addition, the 120 Hz ripple voltage on the DC-Link is caused by the imbalance of the system voltage and current. The effect of this 120 Hz ripple voltage reduces the efficiency of the power generation system by increasing the output current distortion rate. Increasing the capacity of DC-Link can reduce the 120 Hz ripple voltage, but this method is inefficient in price and size. We propose a technique that detects 120 Hz ripple voltage and reduces the effect of ripple voltage without increasing the DC-Link capacity through a controller. The proposed technique was verified through simulations and experiments using a 1 kW single-phase solar power system. In addition, the proposed technique's feasibility was demonstrated by reducing the distortion rate of the output current.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 추계학술대회
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• pp.315-316
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• 2011

This paper presents speed control scheme of the PMSM which has torque compensator to reduce the speed error and ripple. The proposed speed controller is based on the conventional PI control scheme. But the additional torque compensator which is different to the conventional differential controller produces a compensation torque to suppress speed ripple. In order to determine the proper compensation, the activation function which has discrete value is used in the proposed control scheme. With the proposed activation function, the compensation torque acts to suppress the speed error increasing. The proposed speed control scheme is verified by the computer simulation and experiments of 400[W] PMSM. In the simulation and experiments, the proposed control scheme has better control performance compare than the conventional PI and PID control schemes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1003-1005
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• 2000

The switched reluctance drive provides a good adjustable steed characteristics like a D.C series motor. However, because of the torque production mechanism, it also has some disadvantage such as higher torque ripple and fluctuation in speed. To reduce torque ripple and to control speed precisely at low condition current level technique is adopted. The SRM drive with current control of invariable frequency and phase swichting control has good speed regulation characteristics. Digital control system with an 80c196kc micro-controller is used to realize this drive system. Test results show that the control system has the goof ability to achive precise speed control at low speed.

• 전기전자학회논문지
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• 제18권1호
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• pp.128-133
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• 2014

본 논문에서는 출력 리플 전압을 온도에 따라 개선시킬 수 있는 서미스터를 이용한 히스테리틱 벅 변환기를 제안한다. 회로가 민감 할 수 있는 높은 온도에서는 두 비교 전압을 비교적 크게 결정하지만, 회로가 안정적으로 동작 할 수 있는 온도에서는 두 비교 전압을 작게 결정하여, 출력 리플 전압을 최소화 시킨다. 모의실험결과는 출력 리플 전압을 30mV이상 감소시켰으며, 로드 레귤레이션은 0.011mV/mA 이다. 제안하는 회로는 빠른 응답과 저 전력이 요구되는 디지털 회로를 구동하는 전원 관리 회로로서 활용되기 적합하다.

• 대한기계학회논문집A
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• 제31권1호
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• pp.18-25
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• 2007

Linear motor is easily affected by load disturbance, force ripple, friction, and parameter variations because there is no mechanical transmission to reduce the effects of model uncertainties and external disturbance. These nonlinear effects have been reduced for high-speed/high-accuracy position control either through the better motor design or via the better control algorithm that can compensate the nonlinear effects. In this paper, a nonlinear adaptive control algorithm is designed and applied for the position control of permanent magnet linear synchronous motor. In order to estimate and compensate the nonlinear effects such as friction and force ripple, the estimation and the nonlinear adaptive control laws are derived based on the virtual control input and a suitable Lyapunov function. The proposed controller is evaluated through the computer simulations. The control algorithm is also implemented to a DSP board and interfaced to the PMLSM for verifying the realtime control performance.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.614-622
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• 2010

This paper presents a control method, which reduces the pulsating torque and DC voltage problems of a doubly fed induction generator (DFIG)-based wind turbine system. To reduce the torque and power ripple, a current control scheme consisting of a proportional integral (PI) controller is presented in a positive synchronously rotating reference frame, which is capable of providing precise current control for a rotor-side converter with separated positive and negative components. The power theory can reduce the oscillation of the DC-link voltage in the grid-side converter. In this paper, the generator model is examined, and simulation results are obtained with a 3 kW DFIG-based wind turbine system to verify the proposed control strategy.

• Journal of Power Electronics
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• 제11권2호
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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.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1925-1930
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• 2010

겐트리형 리니어 모터의 주행 축은 동기화가 필수적이며 그렇지 못할 경우에는 위치의 어긋남이나 불안정한 동작으로 인해 동기오차가 발생하며 이는 고속 고정밀 선형운동에 악영향을 미친다. 또한 두 리니어모터의 축은 로터리 모터와 달리 동력 전달장치를 제거함으로 인해 모델의 불확실성이나 외란에 민감할 뿐만 아니라 마찰과 리플의 특성에 쉽게 영향을 받는다. 본 논문은 겐트리형 리니어 모터의 주행 축을 대상으로 위치제어에 악영향을 주는 대표적인 비선형 함수인 마찰력과 리플력을 추정하여 보상하며 두 축간의 동기오차를 줄이기 위해 동기제어 알고리즘을 설계하였다. 제안된 비선형 적응제어기는 모의실험을 통하여 성능을 검증하였다.