Trofazni kaskadni pretvarači s izravnom sinkronom širinsko-impulsnom modulacijom

A novel method of direct synchronous pulsewidth modulation (PWM) is applied for control of modular multilevel converters consisting from three standard triphase inverter modules along with an 0.33 p.u. output transformer. The proposed method provides synchronisation of the voltage waveforms for both each module and the composed voltage at the output of the converter. Multilevel output voltage of the converter has quarter-wave symmetry during the whole range including the zone of overmodulation. Both continuous and discontinuous versions of synchronous PWM, based on a vector approach for determination of the pulse patterns, have been analysed and compared using simulations of the systems with low switching frequencies, which normally are used in high power systems.Primijenjena je nova metoda izravne sinkrone šironsko-impulsne modulacije za upravljanje višerazinskim pretvaračima koji se sastoje od tri standardna trofazna izmjenjivačka modula te 0,33 p.u. izlaznog transformatora. Predložena metoda osigurava sinkronzaciju valnih oblika izlaznog napona za svaki izmjenjivački modul i za cjeli pretvarač. Izlazni napon višerazinskog pretvarača ima četvrtvalnu simetričnost u čitavom području vrijednosti, uključivo i područje nadmodulacije. Analizirane su i simulacijski uspoređene kontinuirane i diskontinuirane inačice sinkrone širinsko-impulsne modulacije, zasnovane na vektorskom načelu određivanja impulsnog niza. Simulirani su sustavi s niskom sklopnom frekvencijom, kakvi su standardno sustavi velike snage

Advanced Propulsion Power Distribution System for Next Generation Electric/Hybrid Vehicle

The report essentially summarizes the work performed in order to satisfy the above project objective. In the beginning, different energy storage devices, such as battery, flywheel and ultra capacitor are reviewed and compared, establishing the superiority of the battery. Then, the possible power sources, such as IC engine, diesel engine, gas turbine and fuel cell are reviewed and compared, and the superiority of IC engine has been established. Different types of machines for drive motor/engine generator, such as induction machine, PM synchronous machine and switched reluctance machine are compared, and the induction machine is established as the superior candidate. Similar discussion was made for power converters and devices. The Insulated Gate Bipolar Transistor (IGBT) appears to be the most superior device although Mercury Cadmium Telluride (MCT) shows future promise. Different types of candidate distribution systems with the possible combinations of power and energy sources have been discussed and the most viable system consisting of battery, IC engine and induction machine has been identified. Then, HFAC system has been compared with the DC system establishing the superiority of the former. The detailed component sizing calculations of HFAC and DC systems reinforce the superiority of the former. A preliminary control strategy has been developed for the candidate HFAC system. Finally, modeling and simulation study have been made to validate the system performance. The study in the report demonstrates the superiority of HFAC distribution system for next generation electric/hybrid vehicle

Multi-Level Converters

In the history of modern power electronics evolution, we are now going through the era of multi-level converters [1]. [...

STATOR WINDINGS CURRENTS HARMONICS OF INDUCTION MOTOR, WHICH CONTROL FREQUANCY CONVERTER / DAŽNIO KEITIKLIU VALDOMO TRIFAZIO ASINCHRONINIO VARIKLIO STATORIAUS APVIJŲ SROVIŲ HARMONINĖS SUDĖTIES TYRIMAS

Paper presents examination of induction motor stator windings currents harmonics, when modulation index and carrier frequency are changed. Mathematical model of symmetrical induction motor connected as star without zero wire is developed. Matlab Simulink models are created and tested. Santrauka Nagrinėjama trifazio asinchroninio variklio statoriaus srovių harmoninė sudėtis, keičiant sinusinės impulsų pločio moduliacijos gylį bei nešančiojo signalo dažnį. Pateikta simetriško trifazio asinchroninio variklio, jungiamo žvaigžde be nulinio laido, matematinis modelis. Matlab Simulink pakete buvo sukurtas sinusinės impulsų pločio moduliacijos modelis ir S-Function pagalba variklio modeliai. Imituojant gautos srovės buvo išskleidžiamos greitąja Furjė transformacija. Raktiniai žodžiai: sinusinė impulsų pločio moduliacija; trifazis asinchroninis variklis; statoriaus apvija; harmoniko