Position Sensorless Control of Switched Reluctance Motor Drives
In order to reduce the cost and volume of the motor drive, position sensorless control of switched reluctance machine (SRM) becomes an alternative solution to obtain the rotor position. In general, for torque or speed control of a SRM, position feedback from an encoder or resolver is necessary. Passive rotor position estimation based on the measurement of terminal voltage and phase current of active phases does not require additional hardware and it does not generate additional power losses. Phase self-inductance is estimated only in the active region by using the phase current slope difference at rotating shaft condition. In a three-phase machine, each phase takes up one third of rotor period and three-phase inductance estimation will cover the total rotor period. The rotor position is estimated based on the corresponding phase self-inductance estimation region. When the estimated inductance of a phase reaches the maximum value, the self-inductance estimation is transferred to the next region.