Rotor Position Estimation for Permanent Magnet AC Motor at Standstill

• Main Authors: Sian-Chuan Guo, 郭憲傳
• Other Authors: Sheng-Ming Yang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/38786728158207834176

碩士 === 國立臺北科技大學 === 電力電子產業研發碩士專班 === 100 === Incremental encoders or sensorless control methods are incapable to detect the rotary angle when a motor is at stationary status. As a result, a specific signal sent to the motor is required to obtain information of the rotary angle. However, the control method above for achieving the rotary angle is not suitable to all sensorless controllers when the motor is at stationary status. For example, a motor at stationary has none back-EMF, making measuring methods based on back-EMF useless. This study uses the inductance-rotary angle relation and the principle of inductor saturation to solve the above issue. Information of the motor’s rotary angle may be obtained by applying two voltage pulses of different values and measuring the current response. This method is suitable to measure the initial position of the motor when at stationary. The study begins by first describing the mathematical model of a permanent magnet AC (PMAC) motor and its control principles, followed by describing the physical characteristics of inductance applied this pulse-voltage method. The mathematical model for the pulse-voltage method is then derived. Finally, the method of applying pulse voltage to obtain the rotary angle at stationary status for a PMAC motor is described.