Online Sensorless Position Estimation for Switched Reluctance Motors Using One Current Sensor

• Published in: IEEE transactions on power electronics Vol. 31; no. 10; pp. 7248 - 7263
• Main Authors: Chun Gan, Jianhua Wu, Yihua Hu, Shiyou Yang, Wenping Cao, Kirtley, James L.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bus-current-sensor; Buses (vehicles); Estimating techniques; Estimation; Excitation; High speed; Inductance; Motors; Optical wireless; position estimation; Position sensing; Pulse duration modulation; pulse width modulation (PWM); Reluctance; Reluctance motors; Rotors; Sensorless control; Sensors; switched reluctance motors (SRMs); Transistors; Windings; Bus current sensor (BCS); sensorless control; position estimation; switched reluctance motors (SRMs); pulse width modulation (PWM)
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2015.2505706

This paper proposes an online sensorless rotor position estimation technique for switched reluctance motors (SRMs) using just one current sensor. It is achieved by first decoupling the excitation current from the bus current. Two phase-shifted pulse width modulation signals are injected into the relevant lower transistors in the asymmetrical half-bridge converter for short intervals during each current fundamental cycle. Analog-to-digital converters are triggered in the pause middles of the dual pulse to separate the bus current for excitation current recognition. Next, the rotor position is estimated from the excitation current, by a current-rise-time method in the current-chopping-control mode in a low-speed operation and a current-gradient method in the voltage-pulse-control mode in a high-speed operation. The proposed scheme requires only a bus current sensor and a minor change to the converter circuit, without a need for individual phase current sensors or additional detection devices, achieving a more compact and cost-effective drive. The performance of the sensorless SRM drive is fully investigated. The simulation and experiments on a 750-W three-phase 12/8-pole SRM are carried out to verify the effectiveness of the proposed scheme.