Initial Position Estimation in SRM Using Bootstrap Circuit Without Predefined Inductance Parameters

Initial position estimation is an essential concern for switched reluctance motor (SRM) sensorless controls. However, the existing approaches have a strong dependence on the predefined inductance model, suffer from the electromagnetic interference (EMI), and require high-bandwidth controllers. In this paper, a method to estimate the initial rotor position of SRMs using bootstrap circuits is presented. This method seeks to obtain the rotor position at standstill by analyzing the time required for the charging current reaching its peak value in the bootstrap circuit. This method has many advantages such as the independence of any inductance parameter, the requirement of lower bandwidths of the control system, the reduced EMI influence, and no movement induced to the rotor. The feasibility and the applicability of the proposed method are verified by simulation and experiment studies. Also, the influence of motor parameters on the estimated results is analyzed.