• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.5
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• pp.440-446
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• 2006

The magnitude of output torque in a BLDC Motor depends on torque angle so that the exact initial position of rotor is essentially required for good starting. This paper presents a novel starting control method for smooth starting in a position-sensorless controlled BLDC motor drive for reciprocating compressor of refrigerator. The proposed method starts a BLDC motor using information on the initial position of rotor, determined from current response characteristics, and shows robust starting capability to starting load variations. The effectiveness of the proposed method is verified through experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.139-146
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• 2018

This work puts forward a theoretical analysis on position estimation performance of interior permanent magnet synchronous motor (IPMSM) according to the injection frequency in carrier-based sensorless operation. The effects of spatial harmonics on inductance and voltage distortion due to the nonideal characteristics of IPMSM and inverter are examined as factors influencing the position estimation performance. Furthermore, the position estimation performance is analyzed by calculating the current at the switching instant in several operating conditions. In summary, the half switching frequency injection is more robust to the nonideal characteristics of IPMSM, especially with light load condition. The validity of the analysis is verified by the simulation and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1405-1411
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• 2007

In this paper, a new speed sensorless control based on a fuzzy compensator are proposed for the interior permanent magnet synchronous motor (IPMSM) drives. The conventional proportional plus integrate(PI) control are very sensitive to step change of the command speed, parameter variations and load disturbance. To cope with these problems of the PI control, the estimated speeds are compensated by using the fuzzy logic controller (FLC). In the FLC used by the speed compensator of the IPMSM, the system control parameters are adjusted by the fuzzy rule based system, which is a logical model of the human behavior for process control. The effectiveness of algorithm is confirmed by the experiments.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2005-2007
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• 1998

The rotor speed flux information most important in the speed sensorless vector c So in the paper used current voltage model for flux information in a induction motor. Voltage realized low pass filter insted of integrator, c model realized used of current equation. And cur voltage model estimated flux compoed of Pl cont For conpensation of estimated flux error conpansation algorithm using exactly, rapidly flux obtained for conpensation of estimated flux Proposed control system used TMS320C31 DS high speed processing. The effectiveness of proposed method is verified by simulation experimental results. This method shows h characteristic speed estimation highly flux esti and stable, robust character of load regulation.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.338-344
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• 2004

This paper presents a sensorless speed control of a DC servo motor using a fuzzy-sliding observer in the presences of load disturbances. A fuzzy-sliding observer is proposed in order to estimate the speed of a motor rotor. First, a sliding observer is used to estimate the derivative of the armature current directly using the armature current mesured in the DC servo motor. Second, the optimal gain of the Luenberger observer is set up using the fuzzy control. Experimental results show the good performance in the DC servo motor system with the proposed fuzzy-sliding observer.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.752-760
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• 2018

In this paper, interior permanent magnet synchronous motor (IPMSM) design for sensorless drive, considering magnetic neutral point shift according to magnetic saturation, has been proposed. Sensorless control was divided into a method based on inductance and a method based on back induced voltage. Because induced voltage is very small at zero or low speed, error in rotor initial position estimation may occur. Using the ratio of saliency addresses this problem. When using high-frequency injections at low speed, the rotor's initial position is estimated at the smallest portion of the inductance. IPMSM has the minimum inductance at the d-axis. However, if magnetic saturation leads to magnetic neutral point variation, following the load current change, there is a change in the minimum point of inductance. In this case, it can lead to failure of initial rotor position estimation. As a result, it is essential that the blocking design has an inductance minimum point shift. As such, in this study, an IPMSM design method, by blocking magnetic neutral point change, has been proposed. After determining the inductance profile based on the finite element analysis (FEA), the results of proposed method were verified.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2656-2658
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• 1999

This paper presents a control scheme for a three-phase PWM converter system without any voltage sensors. Two input currents and one load current are measured. In a general PWM converter system, the required AC input and DC output voltage values in order to control the converter are estimated using the differential equations of the converter from the measured input currents and load current values in the switch modes of the converter circuit. The PI controller is used as DC voltage controller and sinusoidal tracking controller which tracks directly AC input current is used as input current controller. The Proposed method is verified by simulations. This paper describes the estimation method and configuration of the controller, and discusses steady state and transient performances of the converter

• Journal of Power Electronics
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• v.3 no.2
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• pp.99-114
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• 2003

This paper presents a feasible development on a highly accurate quick response adjustable speed drive implementation fur general purpose induction motor which operates on the basis of sensorless slip frequency type vector controlled sine-wave PWM inverter with an automatic tuning machine parameter estimation schemes. In the first place, the sensorless vector control theory on the three-phase voltage source-fed inverter induction motor drive system is developed in slip frequency based vector control principle. In particular, the essential procedure and considerations to measure and estimate the exact stator and rotor circuit parameters of general purpose induction motor are discussed under its operating conditions. The speed regulation characteristics of induction motor operated by the three-phase voltage-fed type current controlled PWM inverter using IGBT's is illustrated and evaluated fur machine parameter variations under the actual conditions of low frequency and high frequency operations for the load torque. In the second place, the variable speed induction motor drive system, employing sensorless vector control scheme which is based on three -phase high frequency carrier PWM inverter with automatic toning estimation schemes of the temperature -dependent and -independent machine circuit parameters, is practically implemented using DSP-based controller. Finally, the dynamic speed response performances for largely changed load torque disturbances as well as steady state speed vs. torque characteristics of this induction motor control implementation are illustrated and discussed from an experimental point of view.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.1
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• pp.9-18
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• 2007

This paper proposes the modeling of sensorless drive system using 120 degree conduction method for IPM (Interior Permanent Magnet) BLDC motors and analyzes characteristics of the terminal voltage that is used to detect the rotor position. This paper shows that the ZCP (Zero-Crossing Point) of the measured terminal voltage used In sensorless control is ahead of that of the back EMF of IPM motors because they have a saliency. This research also analyzes that the amount of position detection error is related to saliency, rotor speed, and load condition. In addition, this paper shows that motors have bigger advance angles than we have expected because the ZCP of terminal voltage precedes the actual ZCP, and under operation conditions such as heavy load and high speed it may generate abnormal currents that flow toward opposite direction after phase current becomes zero.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.653-658
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• 2013

This paper describes a new sensorless speed control method for permanent magnet synchronous motor(PMSM) using direct torque control(DTC). The direct torque control offers fast torque response, lesser hardware and processing costs as compared to vector controlled drives. In this paper the current error compensation technique is applied for sensorless speed control of synchronous motor. Through this method, the controlled stator voltage is applied to the synchronous motor so that the error between stator currents of the mathematical model and the actual motor can be forced to decay to zero as time proceeds and therefore, the motor speed approaches to the setting value. Especially, any PI controllers are not necessary in this control method. The simulation results indicate good speed and load responses from the low speed range to the high.