Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Improved Programmable LPF Flux Estimator with Synchronous Angular Speed Error Compensator for Sensorless Control of Induction Motors
Authors Sang-Soo Lee ; Byoung-Gun Park ; Rae-Young Kim ; Dong-Seok Hyun
DOI 10.6113/TKPE/2013.18.3.232
Page pp.232-239
ISSN 1229-2214
Keywords induction motor; programmable low pass filter; sensorless control
Abstract This paper proposes an improved stator flux estimator through ensuring conventional PLPF to act as a pure integrator for sensorless control of induction motors. Conventional PLPF uses the estimated synchronous speed as a cut-off frequency and has the gain and phase compensators. The gain and phase compensators are determined on the assumption that the estimated synchronous angular speed is coincident with the real speed. Therefore, if the synchronous angular speed is not same as the real speed, the gain and phase compensation will not be appropriate. To overcome the problem of conventional PLPF, this paper analyzes the relationship between the synchronous speed error and the phase lag error of the stator flux. Based on the analysis, this paper proposes the synchronous speed error compensation scheme. To achieve a start-up without speed sensor, the current model is used as the stator flux estimator at the standstill. When the motor starts up, the current model should be switched into the voltage model. So a stable transition between the voltage model and the current model is required. This paper proposes the simple transition method which determines the initial values of the voltage model and the current model at the transition moment. The validity of the proposed schemes is proved through the simulation results and the experimental results.