| Abstract |
This paper presents a comprehensive design of a 5 kW silicon-carbide (SiC) based three-phase powerfactor correction (PFC) to achieve high conversion efficiency. It evaluates the efficiency of theconverter by comparing two controllers: a controller without harmonic compensation (HC) in therotational reference frame and a controller with HC in the stationary reference frame. SiC switches, byexhibiting a low capacitive switching loss compared to Si switches, help increasing the switchingfrequency and reducing the size of the line filter. To achieve a very high efficiency converter, thecontroller has an impact on the efficiency, especially at low load. Normally, the current quality of gridconnectedconverter at low load reduces due to the non-linearity of the converter. This reductioninfluences the efficiency. In this paper, two methods are presented to improve the current quality atlow loads: either increasing the converter-side inductance to yield lower current ripple or improvingthe controller to mitigate the low frequency current harmonics. Both methods are investigated in thiswork and it is proved that using a proper controller can help reducing the converter-side inductor to 2/3which has a great impact on the efficiency. An optimized 5 kW SiC based PFC is designed. Maximummeasured efficiency of 99\% at full load is achieved. |
