Initial Rotor Position Estimation of Interior Permanent Magnet Synchronous Motor Using Optimal Voltage Vector

SUMMARYThe initial pole position must be estimated for speed sensorless vector control of PM motors. This paper presents a method to estimate initial pole position for Surface Permanent Magnet Synchronous Motors (SPMSM). For estimating the initial pole position, we utilize Fourier transformation for detecting the inductance change caused by rotor magnetic saliency. The six inductances, obtained by Fourier transformation of the voltage and current measured when a pulse voltage is applied to the motor armature winding respectively, will directly provide the exact information of pole position. The polar distinction is also carried out using Fourier transformation on the basis of the inductance change caused by magnetic saturation. Experimental results on a 0.3-kW 8-pole SPMSM demonstrate the validity of the proposed method. Although no machine was coupled with the tested motor, there was no change in rotor position during pole position estimation. In polar distinction, the maximum rotor position change was only 1.38 electric degrees. A method to estimate initial pole position without a motor voltage sensor is also discussed.

A method for estimating initial pole position of surface permanent magnet synchronous motors using pulse voltage

Yamamoto

Ara

2006

Position sensorless control of interior permanent magnet synchronous motor using extended electromotive force

Tanaka

Miki

2007

Self Cite

SUMMARYDriving a permanent magnet synchronous motor (PMSM) requires the rotor position information to control the motor torque, and this is generally detected by mechanical position sensors such as an encoder or a resolver. However, these sensors increase the machine size and the cost of the drive, and reduce reliability of the system. Therefore, many papers about position sensorless drive method of PMSM have been published. This paper presents a position sensorless control of interior permanent magnet synchronous motor (IPMSM). A mathematical model of IPMSM using the extended electromotive force (EMF) in the rotating reference frame is utilized to estimate the rotor speed and position. This model has a simple structure integrating position information into the extended EMF term. Therefore, the sensorless control based on the mathematical motor model can be implemented simply. The estimation method proposed is based on the principle that the error of the current is proportional to that of extended EMF. This method was carried out using a 6-pole, 400-W, 1750 r/min test motor system. It was found that sensorless speed control was achieved from 80 r/min to 1800 r/min under 0 to 100% loads.

Sensorless vector control of IPMSM with DC link current measurement at low speeds

Kubota

Nakagawa

Kobayashi

2010

SUMMARYThis paper presents a method of estimating pole position of interior permanent magnet synchronous motors (IPMSMs). The proposed method estimates the pole position at low speeds and standstill by measuring only the DC link current of the inverter. The pole position is estimated by using the saliency of the IPMSMs. In order to detect the saliency, three-phase triangular carrier waves are used. The DC link current is measured at the tops and bottoms of the carrier waves. Experimentation is performed to confirm the validity of the proposed method.