Induced Current Reduction in Position-Sensorless SRM Drives Using Pulse Injection

This article proposes a new pulse injection scheme for low-speed position-sensorless switched reluctance motor (SRM) drives with the reduced induced current. Conventional injection methods utilize a constant injection amplitude for position estimation; however, the induced current in idle phases nonlinearly varies with the rotor position and has significant magnitude. It results in large negative torque and degrades the control performance. To mitigate this problem, an injection amplitude regulator based on terminal sliding-mode control is put forward. The amplitude of pulse voltages is adjusted online through a nonlinear control law, and the induced current can be maintained at a minimal level over the whole idle-phase period. Moreover, the adverse impacts of motor parameter uncertainties are eliminated. As a result, the proposed scheme does not require SRM's magnetic characteristics and is easy to implement. The effectiveness was experimentally validated on a three-phase 12/8 SRM setup with comparisons of the conventional method.

Automated summary

This article proposes a new pulse injection scheme to reduce the induced current in low-speed position-sensorless switched reluctance motor (SRM) drives. A constant injection amplitude is traditionally used for position estimation, but the induced current in idle phases varies nonlinearly with the rotor position and has a significant magnitude. To mitigate this problem, an injection amplitude regulator based on terminal sliding-mode control is introduced. It adjusts the amplitude of pulse voltages online through a nonlinear control law to maintain the induced current at a minimal level throughout the idle-phase period.