A Sensorless Direct Torque Control Scheme Suitable for Electric Vehicles

International audienceIn this paper a sensorless control is proposed to increase the efficiency of a Direct Torque Control (DTC) of an induction motor propelling an Electric Vehicle (EV). The proposed scheme uses an adaptive flux and speed observer that is based on a full order model of the induction motor. Moreover, it is evaluated on an EV global model taking into account the vehicle dynamics. Simulations were first carried out on a test vehicle propelled by a 37-kW induction motor to evaluate the consistency and the performance of the proposed control approach. The commonly used European drive cycle ECE-15 is adopted for simulation. The obtained results seem to be very promising. Then, the proposed control approach was experimentally implemented, on a TMS320F240 DSP-based development board, and tested on 1-kW induction motor. Experimental results show that the proposed control scheme is effective in terms of speed and torque performances. Indeed, it allows speed and torque ripple minimization. Moreover, the obtained results show that the proposed sensorless DTC scheme for induction motors is a good candidate for EVs propulsion

Comparative Analysis of Estimation Techniques of SFOC Induction Motor for Electric Vehicles

International audienceThis paper presents system analysis, modeling and simulation of an electric vehicle with different sensorless control techniques. Indeed, sensorless control is considered to be a lower cost alternative than the position or speed encoder-based control of induction motors for an electric vehicle. Two popular sensorless control methods, namely, the Luenberger observer and the Kalman filter methods are compared regarding speed and torque control characteristics. They are also compared against the well-known model reference adaptive system. Simulations on a test vehicle propelled by 37-kW induction motor lead to very interesting comparison results

Direct torque contrl of induction machine based on optimal voltage vector determination according to criterion of torque ripple reduction

U radu je opisana metoda izravnog upravljanja momentom asinkronoga stroja temeljena na određivanju optimalnoga vektora napona prema kriteriju smanjenja valovitosti momenta. Elementi izvornog znanstvenog doprinosa rada su metoda za određivanje promjena vektora statorskog toka i elektromagnetskog momenta u ovisnosti o odabiru upravljačkog vektora napona i modificirani algoritam izravnog upravljanja momentom asinkronoga stroja temeljen na određivanju optimalnoga vektora napona prema kriteriju smanjenja valovitosti momenta. Pri tome je analiziran glavni pogon niskopodnog tramvaja serije TMK 2200 za Zagreb. Opisana metoda je najprije provjerena simulacijski, a zatim eksperimentalno u ispitnom laboratoriju tvrtke Končar - Elektronika i informatika. Metoda za određivanje promjena vektora statorskog toka i elektromagnetskog momenta u ovisnosti o odabiru upravljačkog vektora napona temelji se na izvedenim jednadžbama koje opisuju na koji način pojedini vektori napona izmjenjivača djeluju na upravljačke veličine. Metoda izravnog upravljanja momentom temeljena na određivanju optimalnoga vektora napona prema kriteriju smanjenja valovitosti momenta zahtijeva određivanje točnog položaja vektora statorskog toka unutar sektora kompleksne ravnine. Kod metode se ovisno o pogonskim uvjetima uzimaju u obzir po tri različita vektora napona izmjenjivača, za njih se računaju prediktivne vrijednosti momenta, a odabir vektora napona izmjenjivača koji će se primijeniti u sljedećem vremenskom periodu ovisi o funkciji cilja definiranoj bez težinskih faktora. Stoga se metoda može uvrstiti u prediktivne metode, ali je u odnosu na prediktivno upravljanje momentom jednostavnija. Budući da se računaju samo statorske veličine, te nije potrebno poznavati sve parametre asinkronoga stroja ni brzinu vrtnje, metoda je također robusnija u odnosu na prediktivno upravljanje momentom. Dobiveni rezultati pokazuju kako primjena metode izravnog upravljanja momentom temeljene na određivanju optimalnoga vektora napona prema kriteriju smanjenja valovitosti momenta rezultira najmanjim vrijednostima elektromagnetskog momenta od vrha do vrha i gotovo najmanjom valovitošću momenta koja se za zadane pogonske uvjete može postići primjenom prediktivnog upravljanja momentom.In the doctoral thesis the direct torque control of induction machine based on optimal voltage vector determination according to criterion of torque ripple reduction is proposed. The first element of the doctoral thesis original scientific contribution is the method for the determination of the voltage vectors influence on the stator flux vector and the electromagnetic torque and the second element is the modified algorithm for direct torque control of induction machine based on optimal voltage vector determination according to criterion of torque ripple reduction. Simulation and experimental results for the main propulsion drive of the low-floor tram series TMK 2200 operating in the city of Zagreb are presented in order to show the effectiveness of the proposed method. The experiments were carried out on a model of the main propulsion drive in Končar – Electronics and Informatics, Inc. test laboratory. The method for the determination of the stator flux vector module and the electromagnetic torque changes in dependence on the chosen voltage vector is based on the derived equations which describe the voltage vectors influence on the control variables. The method for the direct torque control of induction machine based on optimal voltage vector determination according to criterion of torque ripple reduction uses exact position of the stator flux vector in the complex plane sector. Depending on the operating conditions, three voltage vectors are taken into account and the predicted values of the electromagnetic torque are calculated for these voltage vectors. The voltage vector that will be applied in the next discrete time period is chosen according to the minimal value of the cost function which does not require weighting factors. Therefore, the proposed method belongs to predictive control methods but the proposed method is simpler in comparison with predictive torque control. The proposed method is also more robust because only stator variables should be calculated, and all induction machine parameters as well as the induction machine speed are not required. The obtained simulation and experimental results show that the application of the direct torque control of induction machine based on optimal voltage vector determination according to criterion of torque ripple reduction results with minimal electromagnetic torque peak to peak values and almost minimal torque ripple which can be achieved when the predictive torque control is applied