• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.46-48
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• 2004

Recently, the study of sensorless drive of IPMSM is coming to be active. In sensorless drive, because the wrong estimation of the initial rotor position brings about the decrease of the starting torque, or a temporary reverse revolution, it is important to know the exact importation of the initial rotor position. In this paper, the initial rotor position estimation method is based on the current peak measured by applying the pulsewise voltage and the current peak is changed according to the rotor position owing to the saliency of the rotor. The effectiveness of the proposed algorithm is verified by the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.72-75
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• 2018

An initial rotor position estimation method is proposed in this study for an interior permanent-magnet synchronous motor without a resolver or an absolute encoder. This method uses least squares approximation to estimate the initial rotor position. The magnetic polarity is identified by injection of short pulses. The proposed estimation process is robust because it does not require complex signal processing that depends on the performance of a digital filter. In addition, it can be applied to various servo systems because it does not require additional hardware. Experimental results validate the effectiveness of the proposed method using a standard industrial servomotor with interior-permanent magnets.

• Journal of Power Electronics
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• v.14 no.3
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• pp.564-571
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• 2014

Rotor initial position is an important factor affecting the control performance of electrically excited synchronous motors. This study presents a novel method for estimating rotor initial position based on sliding discrete Fourier transform (sDFT). By injecting an ac excitation into the rotor winding, an induced voltage is generated in stator windings. Through this voltage, the stator flux can be obtained using a pure integral voltage model. Considering the influence from a dc bias and an integral initial value, we adopt the sDFT to extract the fundamental flux component. A quadrant identification model is designed to realize the accurate estimation of the rotor initial position. The sDFT and high-pass filter, DFT, are compared in detail, and the contrast between dc excitation and ac injection is determined. Simulation and experimental results verify that this type of novel method can eliminate the influence of dc bias and other adverse factors, as well as provide a basis for the control of motor drives.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.602-609
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• 2011

This paper proposes a simple initial rotor position estimation method to obtain a stable startup performance for back EMF-based sensorless control. The proposed estimation method is achieved at standstill by using the current response to difference between each of the stator winding inductance. This initial rotor position estimation method can be easily implemented to control algorithm without any other external devices. The proposed algorithm is also not affected by motor parameter. The validity of the proposed method is demonstrated by experimental result.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.207-209
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• 2005

Recently, the use of IPMSM is coming to be active, in many industrial applications. In sensorless drive of IPMSM, it is important to know the exact information of the initial rotor position, because the wrong estimation of the initial rotor position brings about the decrease of the starting torque, or a temporary reverse revolution, In addition, PMSM is necessary to use the accurate information of the inductance for the precise torque control owing to the reluctance torque. In this paper presents initial rotor position estimation method and, measure method of the each-axis inductance. And to minimize the speed estimations error, the estimated speeds are compensated by using an instantaneous reactive power in synchronously rotating reference frame.

• Journal of Power Electronics
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• v.5 no.1
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• pp.11-19
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• 2005

This paper describes the two control techniques to perform the sensorless vector control of a PMSM by injecting the high frequency voltage to the stator terminal. The first technique is the estimation algorithm of the initial rotor position. A PMSM possesses the saliency which produces the ellipse of the stator current when the high frequency voltage is injected into the motor terminal. The major axis angle of the current ellipse gives the rotor position information at a standstill. The second control technique is a sensorless control algorithm that injects the high frequency voltage to the stator terminal in order to estimate the rotor position and speed. The rotor position and speed for sensorless vector control is calculated by appropriate signal processing to extract the position information from the stator current at low speeds or standstill. The proposed sensorless algorithm using the double-band hysteresis controller exhibits excellent reference tracking and increased robustness. Experimental results are presented to verify the feasibility of the proposed control schemes. Speed, position estimation and vector control were carried out on the floating point processor TMS320VC33.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.1
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• pp.26-32
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• 2005

Rotor position information is essential in the operation of the switched reluctance motor(SRM) drive for generation the phase current switching signals. When an incremental encoder is used as a rotor position sensor, the initial rotor position can not be detected. Some sensorless rotor position estimation methods also have the same problem. In these systems, to initially align the rotor, the forced alignment method has a delay and reverse rotation before the motor can start. Therefore it can not be acceptable for unidirectional drive systems. So the forced alignment method is not desirable in all drive systems and the research on the SRM drives should be directed to a system without rotor alignment. In this paper, a new detection method of initial rotor position using the rate of change of current is suggested. Firstly, di/dt versus θ/sub R/ reference table, which is the relation between the rate of change of current and rotor position, is generated and then the squared Euclidean distance method is used to estimate the rotor position based on the table. The simulated and experimental results are presented demonstrating the feasibility and accuracy of this method.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.45-51
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• 2005

This paper presents a comparison of rotor position estimation of a switched reluctance motor(SRM) with built-in search coils by three methods. The search coil EMFs are not generated in the SRM with built-in search coils at standstill. So an initial rotor position estimation method is needed. In this paper squared euclidean distance, fuzzy logic and neural network methods we proposed for the estimation of initial rotor position. The simulated results of the three methods are compared. The simulated result of the squared euclidean distance method, which has the best performance, is supported by the experimental result.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.344-350
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• 2003

In this paper, an estimation technique of initial rotor position at standstill in Switched Reluctance Motor(SRM) is proposed. In case search coils are used as a position sensor, it has many advantages like low cost, decrease in the volume, high robust characteristics and wide applications. However, the initial rotor position detection is very difficult because the search coil's EMF is not exist at a standstill. In this paper, a near estimation method of initial rotor position is suggested using squared Euclidean distance. The simulation and experiment for the proposed method are achieved. The validity of the proposed method is verified by experimental results.

• Journal of IKEEE
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• v.23 no.2
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• pp.622-627
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• 2019

This paper propose an initial rotor position detection method for sensorless operation of a single-phase permanent magnet synchronous motor(SP-PMSM) with asymmetric air-gap. In general, the sensorless control based on back-emf estimation is difficult to estimate the back-emf at the zero and low speed regions. For this reason, an open loop start-up technique is indispensable, and it is also necessary to detect the initial position of the rotor in order to rotate in a certain direction. In this paper, we propose a method to detect rotor polarity by adding offset voltage to high frequency voltage signal based on the magnetic characteristics of SP-PMSM. The validity and usefulness of the proposed algorithm are verified through several experimental results.