Performance Evaluation of Full SiC Switching Cell in an Interleaved Boost Converter for PV Applications Carl N.M. Ho, Francisco Canales, Sami Pettersson, Gerardo Escobar, Antonio Coccia, and Nikolaos Oikonomou Corporate Research, ABB Switzerland Ltd. Baden-Daettwil, Switzerland carl.ho@ch.abb.com Abstract—The paper presents device characteristics of a recent developed 1.2kV silicon carbide (SiC) switching cell and system performance of an interleaved boost converter using that switching cell. The static and dynamic characteristics of the full SiC switching cell, including a SiC MOSFET and a SiC diode, are experimentally extracted and the advantages of the devices are evaluated. A 2.5kW interleaved boost converter for PV applications is implemented as benchmark test system. It is used to evaluate the system efficiency improvement by using the full SiC switching cell. The experimental results show that the SiC MOSFET greatly improves the efficiency of the converter in contrast to Si 1.2kV IGBT devices. I. INTRODUCTION Silicon Carbide (SiC) material got more attention during the last decade due to the wide bandgap and high breakdown voltage characteristics as alternative to increase the maximum power rating, switching frequency and operation temperature for power semiconductor devices [1]-[3]. Among the types of power semiconductors, power diode was the first device adopting SiC technology and being commercially available. The main advantages are high breakdown voltage and low reverse recovery current [4]-[6]. However, some low power applications, such as PV inverters, can not bring SiC diode’s advantages into full play. This is because Silicon based IGBTs are usually used in high voltage and low switching frequency applications since the turn-off switching loss is relatively high compared to Si MOSFETs due to the well-known current tail phenomenon. Eventually, the switching frequency can not go higher, thus the loss reduction by means of SiC diodes is not significant in the overall semiconductor loss. On the other hand, Si MOSFETs are also an option for low power applications [7]- [8], since it provides short transition time in both turn-on and turn-off durations. However, the efficiency of the converter still suffers from high conduction loss in the MOSFET, especially for high voltage class (>900V) devices. Recently, SiC switches have been demonstrated to overcome the drawbacks of Si based switches. SiC switches provide high breakdown voltage, high junction temperature, fast transient time and low on-resistance [9]-[11]. It is a fact that a full SiC switching cell will bring the benefits of fast switching and low energy loss to modern power electronic systems. Among the SiC switches, SiC MOSFET is the most attractive device for power electronic systems design due to closer compatibility with Si devices, that means normally-off characteristic which will require lower complexity in the desing of the gate drivers. This paper presents characteristics of a SiC switching cell including a 1.2kV / 20A SiC MOSFET and a commercial 1.2kV / 20A SiC Schottky diode, Furthermore, the performance of an interleaved boost converter using the full SiC switching cell for PV applications is presented as a case study. The addressed issues include static characteristics and switching behaviors of the SiC switching cell. Besides, experimental results in a 2.5kW interleaved boost converter using the SiC switching cells are provided to show the benefits of using SiC MOSFET instead of Si IGBT devices in such application. II. SIC DEVICE CHARACTERIZATIONS The semiconductor characterization of a new device is the first work level for prototyping a power electronic system. Generally, results can be classified into two categories, static and dynamic characteristics. Based on the parameters, which are extracted from the semiconductors, the conduction losses and switching losses of a switching cell operating in a system can be estimated [12]-[14]. Moreover, it is important to optimize the system by selecting the most suitable operating point for the semiconductor devices and adjust the speed of the gate drive circuits accordingly to the application. In this section, both experimental extracted characteristics form the full SiC switching cell are presented A. Static Characteristics Static characteristics generally provide the static loss information and the key parameters for guiding the device transient actions. The Tektronix 371A Curve Tracer is used to extract the key parameters from the semiconductor devices [15]. The output characteristics, transfer characteristics, and forward characteristics of the most advance SiC MOSFET and SiC Schottky diode at 25˚C and 150˚C are presented in the following. 978-1-4577-0541-0/11/$26.00 ©2011 IEEE 1923