TY - JOUR
T1 - A Novel Flux Estimator Based on Multiple Second-Order Generalized Integrators and Frequency-Locked Loop for Induction Motor Drives
AU - Zhao, Rende
AU - Xin, Zhen
AU - Loh, Poh Chiang
AU - Blaabjerg, Frede
PY - 2017/8
Y1 - 2017/8
N2 - Accurate flux estimation is essential for the implementation of a high-performance ac motor drive. However, it still faces some problems, which can better be projected by analyzing performances of existing flux estimators, implemented with either a pure integrator or a low-pass filter (LPF). To solve the problems, an alternative flux estimator, implemented with a single second-order generalized integrator (SOGI) and a frequency-locked loop (FLL), is discussed for induction motor drives. The SOGI block included in this algorithm works for integrating the back-electromotive force, which unlike the pure integrator and LPF, does not experience saturation and significant dc offsets caused by different initial conditions. The single-SOGI-FLL estimator does not need additional magnitude and phase compensation, while its performance may deteriorate at low speed, caused by the inverse proportional relationship between its estimated flux and the frequency. A multi-SOGI-FLL flux estimator is, thus, proposed for uncompromised attenuation of dc and harmonic errors even under low-speed condition. Excellent flux estimation can, hence, be offered over the full-speed range, as proven through theoretical studies and experiments.
AB - Accurate flux estimation is essential for the implementation of a high-performance ac motor drive. However, it still faces some problems, which can better be projected by analyzing performances of existing flux estimators, implemented with either a pure integrator or a low-pass filter (LPF). To solve the problems, an alternative flux estimator, implemented with a single second-order generalized integrator (SOGI) and a frequency-locked loop (FLL), is discussed for induction motor drives. The SOGI block included in this algorithm works for integrating the back-electromotive force, which unlike the pure integrator and LPF, does not experience saturation and significant dc offsets caused by different initial conditions. The single-SOGI-FLL estimator does not need additional magnitude and phase compensation, while its performance may deteriorate at low speed, caused by the inverse proportional relationship between its estimated flux and the frequency. A multi-SOGI-FLL flux estimator is, thus, proposed for uncompromised attenuation of dc and harmonic errors even under low-speed condition. Excellent flux estimation can, hence, be offered over the full-speed range, as proven through theoretical studies and experiments.
KW - Flux estimation
KW - Frequency-locked loop (FLL)
KW - Induction motor (IM) drives
KW - Second-order generalized integrator (SOGI)
UR - http://www.scopus.com/inward/record.url?scp=85017649017&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2016.2620428
DO - 10.1109/TPEL.2016.2620428
M3 - Journal article
AN - SCOPUS:85017649017
SN - 0885-8993
VL - 32
SP - 6286
EP - 6296
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 8
M1 - 7637035
ER -