Online sensorless position estimation for switched reluctance motors using one current sensor

Chun Gan, Jianhua Wu, Yihua Hu, Shiyou Yang, Wenping Cao, James L. Kirtley

Research output: Contribution to journalArticlepeer-review


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.
Original languageEnglish
Pages (from-to)7248-7263
Number of pages16
JournalIEEE Transactions on Power Electronics
Issue number10
Early online date4 Dec 2015
Publication statusPublished - Oct 2016

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  • bus-current-sensor
  • position estimation
  • pulse width modulation
  • sensorless control
  • switched reluctance motors


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