To improve the poor precision of flux estimation of the existing algorithm under the PWM wave input of electromotive force(EMF)
a modified stator flux estimation algorithm is adopted. Based on the modification of the existing algorithm
a lowpass filter(LPF)and a compensation unit are used. The compensation unit is for compensation of the amplitude and phase error caused by the LPF. The compensation formula is derived with time phasor method. The optimal compensation coefficient is ascertained via analyses at various synchronous speed. The simulation results show that the new algorithm can effectively eliminate the integrator drift with higher precision of flux estimation under permanent magnet synchronous motor wave input of EMF. The effectiveness of the new algorithm in a sensorless control of permanent magnet synehronous motor is also verified via simulation.
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