Simple speed sensorless DTC-SVM scheme for induction motor drives

The paper focuses on the development of a novel DSP based high performance speed sensorless control scheme for PWM voltage source inverter fed induction motor drives. Firstly, two generic torque and flux control methods the Field Oriented Control (FOC) and Direct Torque Control (DTC), are briefly described. For implementation the sensorless scheme DTC with Space Vector Modulation (DTCSVM) has been selected because it eliminates the disadvantages associated with the DTC while keeping the advantages of both FOC and DTC. Secondly, the simple flux vector observer allowing speed sensor elimination is given. The novelty of the presented system lays in combining the DTC-SVM structure with a simple observer for both torque/flux and speed sensorless control. Furthermore, the DTC-SVM structure which operates in speed sensorless and torque control mode is presented. Finally, the description of a 50 kW laboratory drive and experimental results illustrating properties of the system are given

Sterowanie predykcyjne z optymalną sekwencją łączeń falownika trójpoziomowego zasilającego napęd z silnikiem indukcyjnym klatkowym

W artykule przedstawiono nowatorski system predykcyjnego sterowania z modelem (ang. Model Predictive Control – MPC) bez-czujnikowym napędem z silnikiem klatkowym zasilanym z falownika trójpoziomowego pracującego w szerokim zakresie prędkości łącznie z osłabianiem strumienia stojana. Do ważnych zalet opracowanego układu sterowania napędu należą: bardzo wysoka dynamika regulacji momentu i strumienia, stała częstotliwość łączeń falownika i brak konieczności doboru współczynników wag w funkcji kosztów sterowania predykcyjnego. Opisano zasady teoretyczne zastosowanej optymalnej sekwencji łączeń w metodzie sterowania predykcyjnego. Przedstawione wyniki eksperymentalne napędu o mocy 50 kW potwierdzają zalety zaproponowanego systemu sterowania predykcyjnego.The paper presents a novel model predictive torque control scheme for three-level inverter-fed sensorless induction motor drive operated in wide speed region including field weakening. Among the important features of the developed drive are: very high dynamics, constant switching frequency and no need to adjust weighting factors in the cost function. The theoretical principles of the used optimal switching sequence predictive control methods are discussed. The experimental results measured on 50 kW drive validate performances of the proposed predictive control system

Constant switching frequency predictive control scheme for three-level inverter-fed sensorless induction motor drive

The paper presents a novel model predictive flux control (MPFC) scheme for three-level inverter-fed sensorless induction motor drive operated in a wide speed region, including field weakening. The novelty of the proposed drive lies in combining in one system a number of new solutions providing important features, among which are: very high dynamics, constant switching frequency, no need to adjust weighting factors in the predictive cost function, adaptive speed and parameter (stator resistance, main inductance) estimation. The theoretical principles of the optimal switching sequence predictive stator flux control (OSS-MPFC) method used are also discussed. The method guarantees constant switching frequency operation of a three-level inverter. For speed estimation, a compensated model reference adaptive system (C-MRAS) was adopted while for IM parameters estimation a Q-MRAS was developed. Simulation and experimental results measured on a 50 kW drive that illustrates operation and performances of the system are presented. The proposed novel solution of a predictive controlled IM drive presents an attractive and complete algorithm/system which only requires the knowledge of nominal IM parameters for proper operation