Percorrer por autor "Valtchev, Stanimir"
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- An instantaneous regulation for the wired and wireless super-resonant convertersPublication . Valtchev, Stanimir; Medeiros, Rui; Valtchev, Svilen S.; Klaassens, BenThe paper develops further the method presented in [12], [14], based on energy balance in the resonant tank. This method allows a stable operation of the switches and a higher efficiency of any Series Loaded Series Resonant (SLSR) power converter, especially when contactless energy transfer is concerned. The strategy is based on guaranteeing the correct portion of energy transported by the resonant tank to the load. The portion has to vary corresponding to the error signal taken from the output voltage and remains unchanged if the error signal from the output is at its minimum. In a certain way this method is similar to the Current Mode Control of the classical power converters.
- The Efficient and Stable Charging of Electric Vehicle Batteries: Simplified Instantaneous RegulationPublication . Medeiros, Rui; Valtchev, Stanimir; Valtchev, SvilenThe future charging of the growing fleet of Electric Vehicles (EV) requires new solutions that guarantee a better efficiency and widely spread chargers. Both in fast charging and in slow charging of the electric vehicle (EV) and hybrid electric vehicle (HEV), the wireless charger is the better choice. The wired charger is limited by its cabling and relatively lower output voltage, while the contactless charger can be more universal and safe. What rests to be discovered is the more efficient energy transfer that would have a stable operation. The strategy is based on guaranteeing the correct portion of energy transported by the resonant tank to the load. Some results are shown from this implementation of the instantaneous energy control.
- Experimental study of the energy portions control in Series Resonant ConvertersPublication . Valtchev, Stanimir; Valtchev, SvilenAlthough the Series Resonant Converter (SRC) is not yet fully explored and widely applied it is becoming more and more important for the contactless charging of the Electric Vehicles (EV) batteries. From the point of view of the modern propulsion batteries the careful and reliable charging is very important and good solutions will be the SRC contactless battery charging and the online resonant energy transfer. To their high efficiency must be added the high stability of an instantaneous method of control. The proposed solution is based on correcting the portion of energy that is sent to the load in each half period through the resonant circuit. Experimental results are shown from the implementation of this idea in the SRC working on a loosely coupled (contactless) magnetic connection.
- Hardware-in-the-loop system numerical methods evaluation based on brush DC-motor modelPublication . Mudrov, Mikhail; Zyuzev, Anatoliy; Konstantin, Nesterov; Valtchev, Stanimir; Valtchev, SvilenHardware-in-the-loop (HiL) systems nowadays become popular. During the HiL creation process it is important to select a proper numerical method because the accuracy of the process simulation, in case of the HiL, depends on the correct numerical approach selection. That is why it is important to evaluate the most popular numerical approaches. The “Sequential” Euler (solves equations step-by-step), the Forward Euler (the most popular method for HiL creators), and the Second-order Adams-Bashforth approach are under consideration. A mathematical model based on the DC-motor with independent excitation is selected as a basis for the experimental numerical calculation. In consequence, recommendations for the numerical method selection are given, based on the obtained results.