• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.10
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• pp.1065-1072
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• 2008

A HDD adopts a sensorless brushless DC (BLDC) motor as a spindle motor. Because there is no direct sensor measuring rotor position. open loop commutations with inductive sensing are used to increase the rotor speed up to a certain speed where the zero crossings of the back electromotive force (EMF) voltage are measurable. Therefore, successful open loop commutations are necessary for the stable start-up control of the spindle motors. In this paper, the time scale and the number of the open loop commutations are employed for design parameters to guarantee robustness to torque constant variation and initial rotor position. The design results are verified by experiments on a very low current start-up of the spindle motor with various environment. The experimental results show that the design results can decrease the start-up failure rate considerably.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.705-708
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• 2000

Switched Reluctance motors(SRM) attract much attention in motor because they are reliable and inexpensive. With advance in power electronics and high-speed processors the performance of SRM has been enhanced greatly. But they require rotor position information to operate, In many systems rotor position sensors are undesirable and have disadvantages. To overcome the disadvantages include by position sensors a number of sensorless methods for SRM's have been proposed by researchers. This paper describes a method for indirect sensing of rotor position in SRM's pulsewidth modulation voltage control. The method required no priori knowledge of motor parameters excepts for the number of stator and rotor poles. The detection method uses the change of the derivative of the phase current to detect the position.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.186-189
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A gopinath observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor, A gopinath observer is implemented to compute the speed and position feedback signal. The validity of the proposed scheme is confirmed by various response characteristics.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.229-231
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• 2006

본 논문은 매입형 영구자석 전동기의 고정자 전압방정식으로부터 관측기를 구성하고, 회전자 좌표계상에서 추정속도를 구하여 퍼지제어기를 이용한 속도 보상 센서리스제어를 수행하였다. 전동기의 전압방정식과 퍼지제어기만을 이용하기 때문에 전동기의 기계적 방정식에서 발생하는 기계적 제정수의 영향에 대해 강인한 특성을 갖는다. 제안된 알고리즘의 타당성과 강인함은 실제 구동을 통하여 증명한다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.501-504
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• 1999

과거 벡터 제어의 모델링에 있어 무시되어온 철손의 영향이 최근 여러 논문들에서 연구되어졌으며, 이의 영향이 적지 않음이 밝혀졌다. 본 논문은 속도 센서리스에서의 철손으로 인한 영향을 보상, 직접 회전자 자속 제어와 직접 고정자 자속 제어에 적용하였다. 또한 센서리스 제어에서의 철손의 영향과 그 보상 방법을 보여주며, 시뮬레이션을 통해 이러한 제안의 타당성을 보인다.

• Journal of IKEEE
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• v.26 no.1
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• pp.95-103
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• 2022

In this paper, the efficiency of a sensorless method with square-wave injection for a low-cost inverter, so called B4 inverter is presented. This inverter comprises only 4 switches to reduce system cost. It is distinguished from the conventional B6 inverter that has 6 of switching elements. The B4 inverter, injected a 1 kHz of harmonic wave, has been modelled using the functions and library in Matlab/Simulink. This paper described each component of sensorless algorithm. Among them, the Notch Filter is used to extract the harmonic component of the phase current and a second-order low-pass filter was used to reduce the ripple of the estimated speed. It is shown through simulation that the rotor angle of a permanent magnet synchronous motor is detected by multiplying the current waveform extracted using the notch filter by the harmonic voltage. The feasibility of the proposed method is shown through Simulink 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 KIEE Conference
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• 1996.07a
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• pp.458-460
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• 1996

In this study, the full-state flux observer is designed in the synchronous DQ-frame and the speed adaptation rule is derived by using the MRAS(Model Reference Adaptive System) theory. In this rule, the induction motor becomes a reference model and the flux observer is taken as a adjustable model. A guideline of the adaptation gain is investigated for the precise and stable speed adaptation and the proposed scheme is compared with the conventional one designed in the stationary DQ-frame.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.244-247
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A minimum order state observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor. A minimum order state observer is implemented to compute the speed and Position feedback signal. The validity of the proposed sensorless scheme is confirmed by various response characteristics.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.63-64
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• 2017

This paper proposes a speed estimator for sensorless control of diesel-generator (genset) systems, where the speed of the genset is calculated from the back-EMF frequency of the generator. The back-EMF frequency is extracted from a phase output current by using multiple second-order generalized integrators (SOGIs) connected in parallel and series and separated frequency-locked loops. The proposed method (PS-SOGI-FLL) is able to estimate the fundamental frequency in the distorted output current with high accuracy and strong robustness. Simulation results are shown to verify the validity of the proposed method.