A Universal Two-Sensor Current Detection Scheme for Current Control of Multiphase Switched Reluctance Motors With Multiphase Excitation

In this paper, a universal two-sensor current detection scheme is proposed for the current control of different multiphase switched reluctance motors (SRMs) under multiphase excitation. In the proposed scheme, only two current sensors are utilized to separate the phase currents by selecting the currents flowing through each sensor, and detect the excitation current flowing through the lower switch of each phase. The current overlapping states are analyzed for SRM drives with different phase numbers. Compared to existing schemes, the proposed method is applicable for all three-phase, four-phase, five-phase, and six-phase drives, without external circuits and any changes in converter topologies, which is much easier to implement. For three-phase and four-phase SRM drives, the phase currents can be simply calculated from the two sensor currents, without pulse injection and voltage penalty, which improves the sampling accuracy and system performance. Furthermore, with the proposed scheme, the five-phase and six-phase systems both can be made equivalent to two independent single-sensor systems, where all the phase currents can also be obtained by employing pulse injection. Therefore, it provides a promising solution to phase current detection for different SRMs with multiphase excitation by using only two current sensors. Simulation and experimental results are provided to verify the proposed schemes.