This paper presents a control strategy for restarting procedure of sensorless permanent magnet synchronous motor (PMSM) drives using an indirect matrix converter (IMC). The IMC has many advantages such as long lifetime, compact size, and high reliability. It is widely used in numerous applications such as renewable energy conversion systems and adjustable speed drives. In the adjustable speed drives, recently, the sensorless PMSM drives without an encoder or resolver for detecting a PMSM rotor position have intensively researched. In the rotating condition of the sensorless PMSM drives, if the operation of power conversion system is stopped, it cannot restart without an initial rotor frequency and position of the PMSM. Therefore, in order to restart the sensorless PMSM drives, an additional control strategy is required for detecting the initial rotor frequency and position of the PMSM. In this paper, the control strategy for restarting procedure of the sensorless PMSM drives using the IMC is proposed. The effectiveness of the proposed control strategy is verified by simulation and experiment results.
