Current source gate drivers for 3-phase VSI operated in small-scale wind turbine systems

The paper is dedicated to the improvement of efficiency of small-scale wind turbines' (SSWT) power electronic converters. An efficiency of the 3-phase voltage source inverter that operates with low output voltage (<60 V) and high grid-side input voltage (380 V) is investigated. Such a solution allows skipping the intermediate DC/DC boost converter and thus reducing conversion losses and complexity of a system. The inverter has to oaperate with low duty cycles, which, in turn, demands increasing of switching speed and thus requires application of advanced transistors. To evaluate the switching performance, studies were carried out with various types of switches, namely Si IGBT, Si MOSFET, Cascode SiC JFET, SiC MOSFET using classic gate drivers and proposed current source drivers. Detailed switching waveforms were obtained using the double pulse method and analyzed for each type of the switch. The switching speed was assessed and losses were evaluated. Two types of transistors were selected for testing in the VSI paired with an EMRAX 228 generator. Inverter efficiency data was obtained and analyzed for two types of transistors/drivers and the speed-torque curve applicable for a 3 kW turbine. It is shown that the suggested solution improves the efficiency of SSWTs' inverters.