• The Transactions of the Korean Institute of Power Electronics
• /
• v.2 no.4
• /
• pp.36-44
• /
• 1997

For high performance ac drives, the speed sensorless vector control and the stator flux orientation concept have received increasing attention. This paper describes a speed and flux sensorless vector-controlled induction machine(IM) drive based on the stator flux-oriented control. To improve the accuracy and operating range, the control system employs the previously presented speed and flux estimation methods, and then we present a developed method of estimating the speed of IM. In the proposed method all differential and integral terms have been eliminated by giving a very fast, low-cost, effective and practical alternative to the methods currently available. The effectiveness of the proposed method is verified by simulations and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.8
• /
• pp.1362-1368
• /
• 2016

This paper proposes the improved transition scheme for a sensorless drive of an interior permanent magnet synchronous motor (IPMSM). In order to operate the IPMSM, the current controller can be used until 300 rpm for the initial operation. After that, the control method of IPMSM is changed to the speed controller for the sensorless control method. At that point, the rotor speed overshoot is generated due to the rapid change of the current reference for the speed controller. The proposed algorithm is able to reduce the overshoot of a rotor speed by compensating the estimated feedforward value to the speed controller. The feedforward value of the current reference is estimated by using a coordinate transformation and is approximated to the current reference after the transition of the control mode. The effectiveness of the proposed scheme is verified by experiments using an IPMSM drive system.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.5
• /
• pp.427-436
• /
• 2002

This paper presents an implementation of high-dynamic performance of position sensorless motion control system of Reluctance Synchronous Motor(RSM) drives for an industrial servo system with direct torque control(DTC). The problems of high-dynamic performance and maximum efficiency RSM drives controlled by DTC are saturation of stator linkage flux and nonlinear inductance characteristics with various load currents. The accurate estimation of the stator flux and torque are obtained using stator flux observer of which a saturated inductance $L_d$ and $L_q$ can be compensated by adapting from measurable the modulus of the stator current and rotor position. To obtain fast torque response and maximum torque/current with varying load current, the reference command flux is ensured by imposing $I_{ds} = I_{qs}$. This control strategy is proposed to achieve fast response and optimal efficiency for RSM drive. In order to prove rightness of the suggested control algorithm, the actual experiment carried out at $\pm$20 and $\pm$1500 rpm. The developed digitally high-performance motion control system shown good response characteristic of control results and high performance features using 1.0kW RSM which has 2.57 Ld/Lq salient ratio.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.8-15
• /
• 2019

The PM synchronous motor drives with vector control have been applied to wide fields of industry applications due to its high efficiency. The rotor position information for vector control of a PM synchronous motor is detected from the rotor position sensors or rotor position estimators. The sensorless control based on the mathematical model of PM synchronous motor is generally used and it can be classified into back EMF -based sensorless control and magnet flux-based sensorless control. The rotor position estimating performance of the back EMF-based sensorless control is deteriorated at low speeds since the magnitude of back EMF is proportional to the motor speed. The magnitude of the magnet flux for estimating rotor position in the flux-based sensorless control is independent on the motor speed so that the estimating performance is excellent for wide speed ranges. However, the estimation performance of the model-based sensorless control may be influenced by the motor parameter variation since the rotor position estimator uses the mathematical model of the PM synchronous motor. In this paper, the rotor position estimation performance for the back EMF based- and flux-based sensorless controls is analyzed theoretically and is compared through the simulation and experiment when the motor parameters including stator resistance and inductance are varied.

• Proceedings of the KIEE Conference
• /
• 1990.11a
• /
• pp.326-331
• /
• 1990

In the vector-controlled induction machine drive, mechanical sensors restrict the wide applications of high performance AC drives. So in resent years, many papers have been presented which doesn't need mechanical sensors, named by sensorless vector control. But sensorless control has a few serious problem, one of which Is poor speed estimation in case of incorrect rotor resistance (Rr) information. This paper describes the stator flux orientation speed control strategy with the speed estimation algorithm. and the method of adapting Rr change due to thermal heating. By proposed method. We can acquire precise speed estimation and higher performance.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.216-218
• /
• 2006

In this paper, a new sensorless control based on an adaptive sliding mode observer is proposed for the interior permanent magnet synchronous motor(IPMSM) drives. With using voltage equation only, the adaptive sliding mode observer was investigated. The proposed adaptive sliding mode observer is applied to overcome the problem caused by using the dynamic equation. Furthermore, the Lyapunov theorem is used to prove the system stability included speed estimate and speed control. The effectiveness of the proposed algorithm is confirmed by the experiments.

• Proceedings of the KIEE Conference
• /
• 1997.07f
• /
• pp.2088-2090
• /
• 1997

This paper consists of the speed sensorless vector control of induction motors with the estimation of rotor resistance. In the application of variable-speed induction motor drives, if an inaccurate rotor resistance is used because the rotor resistance can change due to skin effects and temperature variables, it is difficult to achieve a collect field orientation. In this paper, to overcome these difficulties adaptive algorithm is designed for rotor resistance identification. The proposed adaptive algorithm for rotor resistance estimation in the synchronous reference frame is applied by sliding mode current controller satisfing persistent excitation(PE) condition. Adaptive flux observer is here used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Computer simulations are carried out to verify the validity of the proposed algorithm.

• Proceedings of the KIEE Conference
• /
• 1997.07f
• /
• pp.2117-2119
• /
• 1997

Several methods of induction motor drives, which use speed estimators instead of shaft encoders, have been reported. However, the sensorless field oriented control employing stator voltages and currents has difficulty in estimating rotor flux in the low-speed range. This paper investigates the rotor flux estimator which replace integrators with two lag circuits. The experimental results indicate good speed responses.

• Journal of Advanced Marine Engineering and Technology
• /
• v.27 no.4
• /
• pp.503-510
• /
• 2003

A new method of induction motor drive, which requires neither shaft encoder nor speed estimator, is presented. The proposed scheme is based on decreasing current gap between a numerical model and an actual motor. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing the current difference. the rotor approaches to the model speed. that is. reference value. The indirect field orientation algorithm is employed for tracking the model currents. The performance of induction motor drives without speed sensor is generally characteristic of poorness at very low speed. However, in this system, it is possible to obtain good speed response in the extreme low speed range.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.4
• /
• pp.505-512
• /
• 2007

The object of this paper is to study a new control structure for sensorless induction machines dedicated to electrical drives using a three-level voltage source inverter VSI-NPC. The amplitude and the rotating speed of the flux vector can be controlled freely. The scheme investigated is an Enhanced direct torque control "EDTC" for electric vehicle propulsion. The considered application imposes some constraints which are achieved in EDTC control (fast torque response, optimal switching logic, torque control at zero speed, and large speed control. The results obtained for an induction motor indicate superior performance over the FOC type without need for any mechanical sensor.