Sensorless IPMSM drive with rotor position estimator based on analysis of phase current derivatives

Indirect Measurement of Motor Current Derivatives in PMSM Sensorless Drives

“…Accumulation of the current changes i for a set of three subperiods may lead to increased accuracy. Such an attempt still allows rotor position in every PWM period to be calculated [13]. There is no transient between the last passive subperiod in k-1 modulation period and the first passive subperiod in k period.…”

“…The standard methods presented in the references are summarized, followed by the proposal of a new approach to accumulated current change calculation. The assessment of the discussed methods was performed experimentally by the analysis of rotor position estimation errors in PMSM sensorless drive, with the use of the previously presented mathematical algorithm [13]. Motor torque control in sensorless drive involves accurate rotor position estimation at any speed.…”

“…This requirement is fulfilled by the use of different estimation algorithms switched according to actual speed. The considerations were limited to an algorithm designed for medium-and high speed range presented in [13], [14]. The estimator uses motor current derivatives measured when motor terminal voltages are zero to track the angle of EMF vector.…”

“…where diα(0)/dt, diβ(0)/dt, are motor current derivatives transformed into - stationary reference frame; k is a constant calculated from the motor parameters; iq is q-axis motor current expressed in d-q rotating reference frame. The second term of (2) was added to cancel the error caused by the motor saliency in Interior PMSM (IPMSM) [13].…”

Angle Tracking Observer for Filtering Rotor Position Estimates in Sensorless Electric Drives

“…This paper proposes applying an Angle Tracking Observer (ATO) to improve estimation accuracy of the parameter-based estimator presented in [7]. ATOs have been widely researched in regard to conditioning signals from position transducers.…”