• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.110-113
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• 2000

In general, speed control method of the elevator system has used motor pole change type or motor primary voltage control type. But it will change to vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control that primary current of the induction motor be controlled independently with magnetizing current(field current of DC motor) and torque current(armature current of DC motor). In this paper, by analyzing the effect of the time constant variation of rotor of the induction motor on the slip frequency type indirect vector control, a drive system for the motor will be constructed using a fuzzy slip frequency type indirect vector controller with fuzzy control method for estimating the vector time constant in the slip frequency type indirect vector control. The goal of this study is to enabling even more efficient speed control by constructing on elevator driver based on the newly developed drive system.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1058-1065
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• 2015

This paper present a current predicting control method for PMSM (permanent magnet synchronous motor) to improve the tracking performance of stator current, which regards the current vector as the control target. Solving the model state equation in the static frame (α-β frame), the dynamic change of current vector will be gained as three independent terms. These change terms, which contain the prediction of current vector, are discretized and simplified by Taylor series expansion and used to get the voltage vector as the predictive control quantity. SVPWM will transform the control voltage to the switching signal of inverter, which is newly deduced for the current vector. Simulation and experiment results are given to testy and verify the performance of this method.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.181-185
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• 2000

To get high efficiency in variable speed control of induction motor it is required that the vector control should be separated from flux components current and torque component current. In this paper the vector control is modeled by the estimation of the stator flex. Representing induction motor speed controller as a digital system with he use of he 32bit DSP improves the motor control performance The IGBT is used as the switching device and the validity of the proposed vector control is proved through voltage current wave and the characteristics of the velocity response as the drive circuit being simplified

• Journal of Power Electronics
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• v.6 no.1
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• pp.67-72
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• 2006

This paper introduces two different types of AC current control methods for an indirect vector controlled induction motor using a matrix converter. The proposed methods combine the advantages of matrix converters with the advantages of the indirect vector AC current control methods. The first proposed method explains the basic idea of the hysteresis current control method for matrix converters and shows its capability and stability in comparison to the conventional method usually used for VSI. With the aid of the special configuration of the matrix converter, we also propose another current method which is modified from the first one in order to reduce both current ripple and torque ripple. Simulation results have verified the feasibility and the effectiveness of the proposed methods.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.195-198
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• 1997

This paper proposes the effective compensation method of the rotor time constant of induction motor. An indirect vector control method is highly dependent on the motor parameters. To solve the problem of performance degradation due to parameter variation in an indirect vector control of induction motor, we compensate the rotor time constant by current error feedback. The proposed method is a simple on-line rotor time constant compensation method using the information from terminal voltages and currents. As the current error, difference between current command and estimated current, approaches to zero, the value of rotor time constant in an indirect vector controller follows the real value of induction motor. This scheme is valid transient region as well as steady state region regardless of low or high speed. This method is verified by computer simulation. For this, we constructed the simulation model of induction motor, indirect vector controller and current regulated PWM (CRPWM) voltage source inverter (VSI) using SIMULINK in MATLAB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1648-1654
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• 2016

This paper analyzes complex vector current control for the enhanced cross-coupling compensation in accordance with parameter variation in grid-connected inverter system, and verifies through simulation and experiment. Complex vector current control is performed in the synchronous reference frame through d-q transformation. It generates cross-coupling components with rotating nominal angular frequency. In general, cross-coupling elements are compensated by decoupling terms added to output of conventional decoupling PI controller. But, it is impossible to compensate them perfectly which transient response is especially deteriorated such as large overshoot and slow tracking, when variation of grid impedance or measurement error occurs. However, complex vector current control can improve stability and response characteristic of current control regardless of the situation as before. Decoupling controller and complex vector controller are represented through complex forms, and these controllers are analyzed by using frequency response in s-domain, respectively. It is verified that complex vector controller has more superior response characteristic than decoupling controller through MATALB, PSIM and experimental in 5kW grid-connected inverter when L filter parameter is varied from 1.1mH to increase double, 2.2mH.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.65-68
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• 2001

In the vector control methods of induction motor, the stator current is divided into the flux and torque component current. By controlling these components respectively, the methods control independently flux and torque as in the DC motor and improve the control effects. To apply the vector control methods, the position of the rotor current is identified. The indirect vector control use the parameters of the machine to identify the position of rotor flux. But due to the temperature rise during machine operation, the variation of rotor resistance degrades the vector control. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations is executed.

• Journal of IKEEE
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• v.22 no.3
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• pp.716-722
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• 2018

This paper presents a voltage angle control strategy for surface permanent magnet synchronous motor (SPMSM) drives used in low-cost applications, wherein a current vector control is not employed. In the proposed method, the current vector control scheme, which requires high precision phase-current sensing units and a fast calculation capability of a motor drive controller, is replaced with the voltage angle controller. The proposed voltage angle controller calculates a d-axis voltage command to make the d-axis current zero by using a simple equation obtained from the voltage equation of SPMSM. The proposed method shows performance similar to the current vector controlled SPMSM drive during steady-states and its structure is very simple and thus it can be easily implemented with a low-cost microcontroller. The effectiveness of the proposed method is verified through simulations and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1204-1210
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• 2016

The phase currents must be accurately measured to achieve the instantaneous torque control of AC motors. In general, those are measured using the current sensors. However, the measured current signals can include the offset errors and scaling errors by several components such as current sensors, analog amplifiers, noise filter circuits, and analog-to-digital converters. Therefore, the torque-controlled performance can be deteriorated by the current measurement errors. In this paper we have analyzed the influence caused by vector control of 2-phase induction motor when two errors are included in measured phase currents. Based on analyzed results, the compensation method is proposed without additional hardware. The proposed compensation method was applied vector-controlled inverter for 2-phase induction motor of 360[W] class and verified through computer simulations and experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.1001-1008
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• 2003

A time-delay compensation method for vector control system is proposed that can compensate for voltage and current distortions resulting from a time delay in the overall system due to the low pass filter, hysteresis control inverter, microprocessor program computation time, and so on. The proposed scheme estimates the time delay using the difference between the Q-axis stator current command and the time-delayed actual Q-axis stator current in a synchronous reference frame, then compensates the time delay in the voltage and current using the angular displacement of a DQ transformation. Accordingly, the proposed scheme can accurately compensate for the time delay related to the overall system, thereby significantly improving the performance of the vector control system, as verified by simulation and experiment.