• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권11호
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• pp.577-585
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• 2003

This paper proposes a new speed sensorless control method of a permanent magnet synchronous motor using an instantaneous reactive power. In the proposed algorithm, the line currents are estimated by a observer and the estimated speed can be yielded from the voltage equation because the information of speed is included in back emf. But the speed estimation error between the estimated and the real speeds is occured by errors due to measuring the motor parameters and sensing the line current and the input voltage. To minimize the speed estimation error, the estimated speed is compensated by using an instantaneous reactive power. In this paper, the proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of algorithm is confirmed by the experiments.

• 조명전기설비학회논문지
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• 제26권3호
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• pp.61-68
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• 2012

This paper deals with a fault diagnosis algorithm for open faults in the switching devices of PWM inverter-fed IPMSM (Interior Permanent Magnet Synchronous Motor) drive. The proposed diagnostic algorithm is realized in the controller using the informations of three-phase currents or reference line-to-line voltages, without requiring additional equipments for fault detection. Under switch open fault conditions, the conventional dq model used to control an AC motor cannot directly be applied for the analysis of drive system, since three-phase balanced condition does not hold. To overcome this limitation, a fault model based on the line-to-line voltages is employed for the simulation studies. For comparative performance evaluation through the experiments, the entire control system is implemented using digital signal processor (DSP) TMS320F28335. Simulations and experimental results are presented to verify the validity of the proposed diagnosis algorithm.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.71-80
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• 2005

This paper presents the position sensorless vector control of a cylindrical permanent magnet synchronous motor(PMSM) in the field weakening region. The position sensorless algorithm using an instantaneous reactive power of the PMSM is proposed. An instantaneous reactive power can be obtained from the vector product of rotor currents and back emf of the PMSM. Back emf includes the information of rotor speed. So the estimated speed can be yielded from the voltage equation of the PMSM. In other words, the estimated speed is compensated by using an instantaneous reactive power. To extend the speed range of the PMSM in the constant horsepower region, the field weakening control is applied. The proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of the proposed algorithm is verified by the experimental results.

• Journal of electromagnetic engineering and science
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• 제6권1호
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• pp.10-17
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• 2006

For the sake of the potential ability of overcoming interference in TD-SCDMA(time division-synchronous code division multiple access) systems, pilot signal is adopted, but the presented TD-SCDMA protocol has not considered the Rake technique for their mobile terminals. This paper developed a RAKE receiver algorithm and an implementation circuit, which make use of the pilot signal in the burst structure of the TD-SCDMA base station to estimate main channel parameter(channel delays) in the downlink of TD-SCDMA wireless network. The algorithm can reduce multipath interference for the mobile units in multiusers' case. Theoretic performance analysis presented in the paper and computer simulations show that there is a range of BER for Rake receiver and confirm that the proposed RAKE receiver algorithm achieved a better performance under multipath fading propagation and multiusers conditions.

• 전기학회논문지
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• 제64권7호
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• pp.1005-1011
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• 2015

This paper proposes the DC offset compensation algorithm with fast response to the sensed grid voltage in the single-phase grid connected inverter. If the sensor of the grid voltage has problems, the DC offset of the grid voltage can be generated. This error must be resolved because the DC offset can generate the estimated grid frequency error of the phase-locked loop (PLL). In conventional algorithm to compensate the DC offset, the DC offset is estimated by integrating the synchronous reference frame d-axis voltage during one period of the grid voltage. The conventional algorithm has a drawback that is a slow dynamic response because monitoring the one period of the grid voltage is required. the proposed algorithm has fast dynamic response because the DC offset is consecutively estimated by transforming the d-axis voltage to synchronous reference frame without monitoring one cycle time of the grid voltage. The proposed algorithm is verified from PSIM simulation and the experiment.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.174-183
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• 1998

A simple and robust digital current control technique for a permanent magnet (PM) synchronous motor under the parameter variations is presented. Among the various current control schemes for an inverter-fed PM synchronous motor drive, the predictive control is known to give a superior performance. This scheme, however, requires the full knowledge of machine parameters and operating conditions, and cannot give a satisfactory response under the parameter mismatch. To overcome such a limitation, the disturbances caused by the parameter variations will be estimated by using a disturbance observer theory and used for the computation of the reference voltages by a feedforward control. Thus, the steady-state control performance can be significantly improved with a relatively simple control algorithm, while retaining the good characteristics of the predictive control. The proposed control scheme is implemented on a PM synchronous motor using the software of DSP TMS320C30 and the effectiveness is verified through the comparative simulations and experiments.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.58-63
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• 2012

The Test Signal Method is adopted to analyze the impact of thyristor controlled series capacitor (TCSC) on sub-synchronous oscillation. The results show that the simulation system takes the risk of Sub-synchronous Oscillation (SSO) while the TCSC is operating in the capacitive region. A supplementary excitation damping controller (SEDC) is used to mitigate SSO caused by the TCSC. A new optimization method which is aimed for optimal phase compensation is proposed. This method is realized by using the particle swarm optimization (PSO) algorithm. The simulation results show that the SEDC designed by this method has superior suitability, and that the secure operation scope of the TCSC is greatly increased.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.771-774
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• 1999

This paper presents a new timing structure for real time communications and its performance analysis. The cycle time consists of several "one time slot" which may be an interval defined by a synchronous traffic part followed by an asynchronous traffic part. If a station receives a token within a synchronous interval, it transmits its synchronous message if any, otherwise it may transmit an asynchronous message. This scheme is different from usual allocation schemes which divide one cycle into alternating synchronous and asynchronous subslots. This protocol is designed to prevent low priority messages from delaying too much due to lots of high priority messages. We propose the algorithm and show its justification by simulation.

• 한국정밀공학회지
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• 제15권8호
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• pp.60-70
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• 1998

A harmonic drive is compact torque transmission device with no backlash which is widely applied in industrial field to transmit torque precisely. However, one of the disadvantages of harmonic drives is the existence of mechanical flexibility caused by its structural properties, which imposes great limitation on designing precise controller This paper proposes a nonlinear controller for synchronous operation of DC servo-motors with harmonic drive, using Integrator Backstepping method. Furthermore, an alternative algorithm for serial type synchronous operation of multiple DC servo-motors is proposed. Simulation results by SIMULINK for proposed controller shows considerably small error and rapid approach to reference input, which can be adapted to industrial applications.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권11호
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• pp.541-547
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• 2003

Speed and torque controls of permanent magnet synchronous motors are usually attained by the application of position and speed sensors. However, speed and position sensors require the additional mounting space, reduce the reliability in harsh environments and increase the cost of a motor. Therefore, many studies have been peformed for the elimination of speed and position sensors. This paper investigates a novel speed sensorless control of a permanent magnet synchronous motor. The proposed control strategy is based on the MRAS(Model Reference Adaptive System) using the state observer model with the current error feedback and the magnet flux model as two models for the back-emf estimation. The proposed algorithm is verified through the simulation and experiment.