This paper presents an improved rotating restart method for a sensorless permanent magnet synchronous motor (PMSM) drive system using repetitive zero voltage vectors. To restart the sensorless PMSM drive system, a method for estimating initial rotor position and speed is required due to the absence of sensors such as encoders and resolvers. The rotor position and speed can be estimated using the short-circuit current vectors generated by applying zero voltage vectors. However, the estimated rotor position and speed can be inaccurate. The inaccurate rotor position that causes the current is distorted by the back-electromotive force of the PMSM, and it is impossible to precisely control the system. Therefore, an improved rotating restart method for the sensorless PMSM drive system using repetitive zero voltage vectors is proposed. The effectiveness of the proposed method is verified through simulation and experimental results using a 5-kW PMSM drive system.
Manuscript received November 28, 2018; revised March 6, 2019; accepted April 3, 2019. Date of publication May 8, 2019; date of current version January 3, 2020. This research was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry and Energy (MOTIE) of the Republic of Korea under Grant 20171210201100 and Grant 20172020108970. (Corresponding author: Kyo-Beum Lee.) D.-W. Seo is with the Power Grid Solution Division Power & Industrial System R&D Center, Hyosung, Seoul 08592, South Korea (e-mail:, sdw6737@hysung.com).
