Improved sensorless control of a permanent magnet machine using fundamental pulse width modulation excitation

Abstract

A new method to estimate the rotor position of permanent magnet synchronous motor (PMSM) drives over a wide speed range, including zero frequency is introduced. The method measures the motor current derivative in response to the standard pulse width modulation (PWM) sequence to estimate rotor position. No additional signal injection or separate test vectors are required although modification is needed when narrow PWM voltage vectors occur. Three compensation techniques are proposed to improve the quality of the position estimation and reduce current distortion when narrow vectors are used for position estimation. Experimental results for sensorless speed and position control of a 4 kW PMSM verify the effectiveness of the proposed techniques.

Motor Temperature Monitoring Based on Impedance Estimation at PWM Frequencies

“…The outcome of this calculation consists in 20 values of R EQ , each of them representing the weighted average of the winding resistance R k within the relevant 5 kHz bands. According to (9), the average values of R EQ are mainly affected by the values of R k found at frequencies where the voltage excitation U k is larger. Obtained in the prescribed manner, sets of 20 R EQ values are shown in Fig.…”

“…In each test, relevant data regarding R k (f) change are weighted-averaged over the entire frequency interval from 10 kHz up to 100 kHz by using (9). For each winding temperature  w , (9) provides the weighted average resistance R EQ ( w ) for the given temperature.…”

“…Instead of test signals, the method uses the PWM voltage pulses as an intrinsic input disturbance available from all three-phase inverters. The same approach has been advantageously used in estimating the rotor position in shaft-sensorless drives [9][10][11][12][13].…”

Sensorless speed control of five-phase PMSM drives with low current distortion

“…The main difficulty when applying current derivative-based position estimation schemes to real systems arises from the parasitic effects within the motor, the inverter and the cabling [24]. And hence, narrow active voltage vectors must be extended to a minimum vector duration tmin which is set according to the high frequency decay.…”

Open loop control of a stepping motor with step loss detection and stall detection using back-EMF based load angle estimation

“…Research concerning sensorless control for PMSM and induction machines is getting mature [7]- [12]. Research efforts have also been made to implement sensorless control for stepping motors [13]- [15].…”