• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.59-70
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• 2002

This paper proposes a position and speed sensorless vector control for Synchronous Reluctance Motor(SynRM) operating at optimum efficiency and high response, in which core loss is taken into account, and discusses the performance of system. The proposed control scheme is based on the flux estimation combined stator voltage and current. In this paper, current angle condition of efficiency optimization which minimizes the copper and iron losses is derived based on the equivalent circuit model of the SynRM. The research result of closed loop position and speed control with efficiency optimization control is given to verify the proposed scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.65-71
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• 2006

In this paper, a novel motor control method is proposed to improve the performance of sensorless drive of BLDC motors. In the terminal voltage sensing method, which is a great portion of sensorless control, a precise rotor position cannot be obtained when excessive input is applied to the drive during synchronous operation mode. Especially in the transient state, the response characteristic decreases. To cope with this problem, the unknown input (back-EMF) is modelled as the additional state of system in this paper. Taking into account the disturbance adopted by the back-EMF, the observer can be obtained by the augmented system equation. An algorithm to detect the back-EMF of the BLDC motor using the state observer is constructed. As a result, the novel sensorless drive of BLDC motors that can strictly estimate rotor position and speed is proposed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.185-191
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• 2010

This paper describes a new position sensorless control for the switched reluctance motor (SRM) by monitoring the rate of change of current with respect to the inductance variation. Two consecutive switch-on times in hysteresis current control are compared to calculate the rate of change of current and hence to estimate the rotor position and speed. The proposed sensorless control algorithm is simple to implement as it does not depend on extensive computation or additional hardware. Simulation and experimental results are presented to demonstrate the feasibility of the proposed sensorless control method.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.333-335
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• 2006

본 논문은 영구자석 교류 전동기의 센서리스 위치 오차 최소화 제어 방법에 관한 것으로, 회전자의 위치오차가 최소화 하도록 회전자 속도 추정 gain을 자동으로 조정함으로써 회전자의 속도 및 위치에 대한 오차를 최소화하기 위한 방법이다. 본 논문의 구성은 회전자 위치 오차를 최소화하기 위한 제어기와 이를 회전자 속도 게인으로 활용하는 적용 대상으로 구성 되어 있다. 이는 모터의 온도 및 운전 환경에 따른 parameter의 변동에 강인하도록 제어기의 게인을 자동 설정하며 회전자의 오차를 최소화 하도록 하는 제어기를 제안한다. 또한 본 논문에서 제한하는 알고리즘을 검증하기 위하여 시뮬레이션 하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.3
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• pp.154-161
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• 2005

This paper proposes a speed-sensorless induction motor control system using a rotor speed compensation. To explain the proposed system, this paper describes an induction motor model in the synchronous reference frame for the vector control. The rotor flux is estimated by the rotor flux observer using the reduced-dimensional state estimator technique. The estimated rotor speed is directly obtained from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. The error of the rotor time constant is indirectly reflected in the rotor speed compensation using the compensation of the flux error angle. To precisely estimate the rotor flux, the actual value of the stator resistance, whose actual variation is reflected, is derived. An implementation of pulse-width modulation (PWM) pulses using an effective space vector modulation (SVM) is briefly mentioned. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.336-343
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• 2008

This paper proposes a novel sensorless control scheme for a Permanent Magnet Synchronous Motor (PMSM) by using a parallel reduced-order Extended Kalman Filter. The proposed scheme can obtain rotor position and speed by back-EKF that is estimated by reduced-order ETD and save computation time great)y due to using a parallel structure that works by turns every sampling time. Therefore, proposed scheme has merits of conventional EKF, and problems of parameter sensitivity are partially overcome. And proposed scheme can safely estimate rotor speed and position by using new algorithms according to driving regions. Experimental results show the validity of the proposed estimation technique, and to verify the merit of the proposed scheme, a comparison of a new reduced-order EKF algorithm with a conventional EKF algorithm has been also made in terms of computation time.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.1
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• pp.29-34
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• 2005

The wound induction motor can provide high starting torque and reduced starting current simultaneously by inserting large resistor externally when starting. And this technique is one of the well known methods among the induction motor starting methods and generally used for heavy load starting such as crane and cement factories. The conventional PI controller has been widely used in industrial application due to the simple control algorithm and is generally used for control of current torque, position, and speed for the wound induction motor drive system. However, the conventional control system for wound induction motor may result in poor performance because sensors have to be used but are often limited by the environmental condition. Recently, to overcome these problems, many sensorless vector control methods for the wound induction motor have been studied. This paper presents a MRAS method for sensorless vector control of the wound induction motor drive. In the conventional MRAS method, in low frequency, the stator resistance variation may result in poor performance. Therefore, this paper presents a MRAS method with stator and rotor resistance tuning for sensorless vector control of the wound induction motor to overcome several shortages of the conventional MRAS caused by parameter variation and to enhance the robustness of the sensorless vector control. The validity and effectiveness of the proposed method is verified through digital simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.455-464
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• 2019

The sensorless control based on the flux linkage of PM synchronous motors has excellent position estimation characteristics at low speeds. However, a limitation arises because the integrator of flux estimator is saturated by the DC offset generated during the analog to digital conversion(ADC) process of the measured current. In order to overcome this limitation, HPF with a low cutoff frequency is used. However, the estimation performance is deteriorated (Ed- the verb deteriorate already includes the meaning of 'problem') at high speed due to the low cutoff frequency, and increasing the cutoff frequency of the HPF induces further problems of phase leading and initial starting failure at low speeds. In this paper, the cutoff frequency of HPF was synchronized to the operation frequency of the motor: at low speeds the cutoff frequency was set to low in order to reduce the phase leading of the estimated flux, and at high speeds it was set to high to raise the DC offset removal performance. As a result, the operating range was increased by 200%. Furthermore, a phase compensation algorithm is proposed to reduce the phase leading of the HPF to less than 1.5 degrees over the full operating range. The proposed sensorless control algorithm was verified by experiment with a PM synchronous motor for a washing machine.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.503-504
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• 2015

This paper deals with the analysis of characteristics of position and speed estimator of an adaptive sensorless control algorithm for PMSM drives. The analysis shows that the back emf constant variation results in the position estimation error, but does not the speed estimation error. The simulation and experimental results are shown to verify the analysis result and the usefulness of the back emf constant estimator.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.31-35
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• 2010

In this paper, a speed estimation method at coasting operation in an induction motor speed sensorless control for railway vehicle traction systems is presented. At coasting operation, there is no information obtaining rotor speed since all switches of an inverter are turned off. The inverter frequency should be synchronized with the rotor frequency for repowering at coasting condition. The proposed method injects DC current to the induction motor during a short time, then the flux angle and rotor speed needed for control can be estimated rapidly.