A Buck-Boost Transformerless DC–DC Converter Based on IGBT Modules for Fast Charge of Electric Vehicles

Abstract

A transformer-less Buck-Boost direct current–direct current (DC–DC) converter in use for the fast charge of electric vehicles, based on powerful high-voltage isolated gate bipolar transistor (IGBT) modules is analyzed, designed and experimentally verified. The main advantages of this topology are: simple structure on the converter’s power stage; a wide range of the output voltage, capable of supporting contemporary vehicles’ on-board battery packs; efficiency; and power density accepted to be high enough for such a class of hard-switched converters. A precise estimation of the loss, dissipated in the converter’s basic modes of operation Buck, Boost, and Buck-Boost is presented. The analysis shows an approach of loss minimization, based on switching frequency reduction during the Buck-Boost operation mode. Such a technique guarantees stable thermal characteristics during the entire operation, i.e., battery charge cycle. As the Buck-Boost mode takes place when Buck and Boost modes cannot support the output voltage, operating as a combination of them, it can be considered as critically dependent on the characteristics of the semiconductors. With this, the necessary duty cycle and voltage range, determined with respect to the input-output voltages and power losses, require an additional study to be conducted. Additionally, the tolerance of the applied switching frequencies for the most versatile silicon-based powerful IGBT modules is analyzed and experimentally verified. Finally, several important characteristics, such as transients during switch-on and switch-off, IGBTs’ voltage tails, critical duty cycles, etc., are depicted experimentally with oscillograms, obtained by an experimental model.

Analysis of the Usefulness Range of the Averaged Electrothermal Model of a Diode–Transistor Switch to Compute the Characteristics of the Boost Converter

“…In order to improve the accuracy of modelling this characteristic, the heat generation model should take into account not only power losses related to the conduction of the IGBT but also power losses resulting from its switching. The method of modelling losses associated with the transistor switching for the needs of the averaged diode-transistor switch model is presented in [27] for the MOSFET transistor. In the range of very low values of the I out current, the cause of the discrepancy may also be the omission of leakage currents of the transistor and the diode at the stage of formulating the considered model.…”

“…Averaged models of the diode-transistor switch have been described in the literature for many years, and the results of computations performed using such models are described for different DC-DC converters [3,12,[17][18][19][20][21][22][23][24][25][26]. However, until recently, such models were formulated only for converters containing ideal switches [3,[17][18][19][20][21][22] or Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) [12,[23][24][25][26], although IGBTs are not less popular in this application [27][28][29][30]. It is worth noting that when using models of ideal switches, it is impossible to compute the junction temperature of the diode and the transistor operating in the DC-DC converter.…”

Improvement of Multilevel DC/DC Converter for E-Mobility Charging Station

“…Based on this characteristic, the converter circuit can be simplified by removing the gate amplifier power supply of the multilevel topology, which uses multiple switching devices according to the circuit configuration. Thus, a field effect transistor of the multilevel converter, excluding the lowest level of buck converters configured in series in the multilevel converter, is configured in the negative terminal of the input power supply, and the gate amplifier voltage is used as the power supply voltage, thus simplifying the circuit configuration [17][18][19][20].…”

Maximum Power Point Tracking Techniques for Photovoltaic Panel: A Review and Experimental Applications

“…In the non-isolated, the configuration indicates that the mentioned barrier is vanished and therefore, the efficiency tends to be higher since the number of components is lower [21]. Known non-isolated architectures are Cuk, SEPIC, boost, buck-boost, positive superlift Luo, and ultra-lift Luo [22][23][24][25][26][27].…”