• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.82-88
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• 2009

Low costed position sensor or sensorless control method is generally used in the motor control for home appliance because of the material cost and manufacture standard restriction. In conventional sensorless method, the stator resistance and back-EMF coefficient are varied by the motor speed and load torque variation. Therefore, position error occurred when the motor is operated by sensorless control method because of these variations. In this paper, the compensation method is proposed for sensorless position error using 2 hall sensors.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.15-22
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• 2009

In this paper, a sensorless control of PMSG(Permanent Magnet Synchronous Generator) for small wind turbine systems, which is based on stator flux and back-emf estimation. Also, a cost-effective AE/DC/AC converter that consists of a two-leg three-phase PWM converter and a half-bridge PWM converter is used for vector control of PMSG, which is impossible with the conventional diode-rectifier type converter. A sensorless control algorithm can eliminate pulse encoders for speed measurement, which reduces the system cost. Using PSIM simulation, the validity of the converter control performance and MPPT control of PMSG have been verified.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.38-43
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• 2011

This paper presents the improvement of start-up characteristic of sensorless controlled IPMSM(Interior Permanent Magnet Synchronous Motor) with SMO(Sliding Mode Observer). It is difficult to utilize the rotor position information at starting point for the back EMF estimation based sensorless control. For this reason, open loop control is normally used during start-up period. However, changing from open loop to closed loop control might bring a problem on the transient characteristics for difference load conditions. To solve this problem, we add another rotor angle controller. Simulation results and experimental results are presented to verify proposed method.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.2
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• pp.41-50
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• 1993

This paper describes an effort to develop a microcomputer-based parameter identification system for three phase and two phase brushless DC motor. Back EMF equation is derived from back EMF waveform of three phase and two phase brushless DC motor. In this paper, a new identification algorithm for the brushless DC motor parameters by Pasek's technique is developed. It is found that Pasek's equation is valid for the brushless DC motor, too. The results obtained clearly shows that it is possible to implement the identification system for the determination of the brushless DC motor parameters. To minimize errors due to the ripple component in the measured armature current, digital averaging firis employed. The whole identification process of signal generation, measuring, parameter determination is fully automated. The use of the propod method in the parameter identifition system shows that the averaged current curve is in excellent agreement with the estimated current curve. Therefore, this close agreement confirms the validity of this technique.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.4
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• pp.291-299
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• 2007

To operate a permanent magnet synchronous motor (PMSM) at a maximum torque per ampere (MTPA) operation point, the exact values of machine parameters such as inductances and back-EMF constant, which are sensitive to motor phase currents and temperature respectively, should be blown. An adaptive estimation method for on-line estimation of the machine parameters is not suitable for practical applications since it has difficulties in estimating exact values and requires complex mathematical calculations. The purpose of this paper is to present a simple MTPA operation point tracking control strategy for vector controlled PMSM drives with slow dynamic loads. The proposed method searches MTPA operation points by modulating current phase angle and observing the variation in command power. The current angle modulation strategy is designed to sense the effect of load variations in the command power. Therefore, the proposed method can track the MTPA operation points of the PMSM regardless of load variations. Computer simulation and experimental study is also presented to show the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.242-243
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• 2008

사다리꼴 역기전력을 갖는 BLDC 전동기 제어는 구형파 전류를 인가함으로서 DC 모터와 같은 제어를 할 수 있어 많은 응용 분야에 사용되고 있다. 구형파 전류를 인가하기 위하여 연구된 PWM방식을 분석해 보면 몇 가지 문제점을 가지고 있다. 기존의 연구내용으로는 유니폴라 PWM방법, 바이폴라 PWM 방법, 하이브리드 PWM 방법이 있으나 PWM을 정확히 분석해보면 원하는 전압을 인가할 수 없는 부분이 있음을 알 수 있다. 특히 방향을 바꾸는 시점이나 속도를 급격히 줄이는 부분에서는 원하는 전압이 인가되지 않음을 알 수 있다. 본 논문에서는 이러한 문제점을 분석하고 정확한 전압이 인가될 수 있는 방법을 제안한다.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.821-823
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• 2002

브러시리스 직류 전동기(Brushless DC Motor : BLDCM)는 기존의 직류 전동기의 단점인 브러시를 제거한 것으로 제어가 간단하면서도 넓은 범위에서 속도 제어가 가능하고 효율이 높으며 저가로 제어기 제작이 가능하다. 그러나 BLDC기을 구동하는데 필수적인 센서는 제품의 가격을 증가시킬 뿐만 아니라 외부 환경-특히 온도의 영향을 많이 받는다는 단점이 있다. 이러한 것은 BLDCM의 사용 환경이 다양해짐에 따라 많은 문제점을 야기하게 되며 따라서 센서리스 구동이 요구된다. 본 논문에서는 BLDCM의 센서리스 구동에서 정상상태 운전뿐만 아니라 안정된 초기 구동에 관한 연구를 수행한다. 정상상태 운전은 측정된 역기전력을 이용하여 회전자의 위치를 결정함으로써 이루어지며, 초기 구동을 개선하기 위해 환류 다이오드로부터 측정된 전류 신호를 이용하여 초기 구동을 하게 된다.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.58-62
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• 1990

Air gap flux density is obtained strictly from air gap permeance and MMF distribution using the design parameter of BLDCM when the stator slot is considered. Then the theoretical equations representing the cogging torque and BEMF are proposed. The effect of skew is described analytically, and skew effect on air gap permeance and MMF is studied. Consequently we verified analytically that skew of slots and magnets influenced on the reduction of the cogging torque and BEMF ripple, and the shape of BEMF.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1455-1458
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• 2005

This paper presents the method of reducing torque ripple of Blushless Direct Current(BLDC) motor. In the BLDC motor, the torque is decided by the back-EMF and current waveform. If the back-EMF is constant, the torque ripple depends on the current ripple during commutation period. The current in commutation period is acquired by circuit analysis and then the torque ripple simply can be reduced by varying input voltage to flow the current continuously. And suggested method is confirmed by dynamic with parameters of 500W BLDC motor.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.878-879
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• 2011

본 논문에서는 10극 12슬롯의 분수슬롯을 가지는 영구자석 동기전동기의 권선방법을 알아보고자 한다. 권선방법은 수학적인 수식을 통해 계산되었고 권선법에 따른 결과는 2차원 유한요소법으로 검증을 하였다. 무부하 역기전력과 토크 파형을 비교하여 분수슬롯 권선법의 최적화된 설계방법을 찾고자 하였다.