Three-level converters feature with low switching loss and small filter size. In order to realize high power density design for three-level converters, SiC MOSFETs may be selected instead of using Si IGBTs. However, all SiC MOSFETs based converters suffer from extreme high total cost. In this paper, a SiC MOSFET & Si device hybrid ANPC converter is proposed. It consists of four Si active switches and only two SiC MOSFETs. Thus, it has lower total cost compared to all SiC MOSFETs based ANPC converter. Furthermore, a dedicated modulation scheme is proposed to completely move all the switching events from Si devices to SiC MOSFETs by using redundant switching states. As a result, the switching losses are significantly reduced and extremely high efficiency is achieved. The proposed converter has fully utilized the low switching loss advantage of SiC MOSFET and the low-cost advantage of Si devices, which shows significant superiority in high-end grid-connected inverter and rectifier applications.

Power electronics and communication electronics are both based on electromagnetic theory, but they are usually regarded as two distinct subfields in electrical engineering. In fact, however, electric power is the most common matter-based carrier of messages; thus, power electronics and communications can be jointly considered. Here we study the essential nature of dc-dc power converters and characterize the similarity of their operation principle to that of communication systems. Based on this similarity and the double modulation methods used in power electronics and communication, a double modulation strategy for both power and data is presented and applied in dc-dc power converters to achieve what we call ‘talkative power’. A modulation strategy called frequency hopping-differential phase shift keying (FH-DPSK) is also presented to overcome the crosstalk between chosen transmission systems. The proposed talkative power strategy sheds new light on and provides inspiration for the further development of power electronics and communication.

Continuously increasing demand of microgrids with high penetration of distributed energy generators, mainly renewable energy sources, is modifying the traditional structure of the electric distribution grid. Major power consumer countries are looking for alternative energy sources to avoid the impact of higher fossil fuel consumption. Thus, different policies have been promulgated to promote renewable energy technologies (RETs) and distributed energy resource (DER) deployment and are encouraging technological innovation. These policies aim to reduce greenhouse gas (GHG) emissions and achieve energy security and independence to meet an ever-increasing electricity demand. Many studies have been performed on the successful integration of RET and DER operation and control, protection and stability issues, all simultaneously and satisfactorily implemented during feasible microgrid operation. However, apart from the technical challenges, few microgrid studies exist on effective policies and incentives for microgrid promotion and deployment. This survey investigates the policy, regulatory and financial (economical and commercial) barriers, which hinder the deployment of microgrids in the European Union (EU), United States (USA) and China. In this paper, a clear view on microgrid policy instruments and challenges are investigated to aid future developments.

With the shortage of the energy and ever increasing of the oil price, research on the renewable and green energy sources, especially the solar arrays and the fuel cells, becomes more and more important. How to achieve high step-up and high efficiency DC/DC converters is the major consideration in the renewable grid-connected power applications due to the low voltage of PV arrays and fuel cells. The topology study with high step-up conversion is concentrated and most topologies recently proposed in these applications are covered and classified. The advantages and disadvantages of these converters are discussed and the major challenges of high step-up converters in renewable energy applications are summarized. This paper would like to make a clear picture on the general law and framework for the next generation non-isolated high step-up DC/DC converters.

The crosstalk voltage on the gate source terminal of SiC power MOSFETs in a phase leg circuit is composed of the gate-drain capacitor introduced voltage and the common source inductor introduced voltage. The mathematical model of the crosstalk voltage indicates that to suppress two types of crosstalk voltage, there exists a contradictory requirement on the off-state gate loop impedance. This challenge reduces the effectiveness of conventional crosstalk elimination methods. As an improvement, a crosstalk voltage suppression circuit that synchronously eliminates the crosstalk voltage of gate-drain capacitance and the common source inductance is proposed. In this work, instead of creating low impedance gate loop in the off state, a high impedance gate loop is formatted to eliminate the voltage drop on the common source inductance. Meanwhile the potential false turn-on or the negative voltage spikes caused by gate-drain capacitance is eliminated by the pre-charge voltage in the gate source capacitor. The required pre-stored charge is analyzed considering the nonlinear behavior of the junction capacitance of the SiC MOSFETs. The proposed gate driver is experimentally verified in different switching conditions.

Nowadays, due to the growing demands of data centers, the traditional line frequency transformer based data center power distribution system is becoming bulky and inefficient. Although SST based DC-PDS dramatically improves the system efficiency, the traditional multi-cell SST with input-series output-parallel (ISOP) architectures has limitations. Using high voltage devices to develop single-cell SST improves system performance, however, its application is limited by high voltage power devices. As an alternative solution, achieving high blocking voltage through the series connection of low voltage devices brings several advantages. Nevertheless, the series connection brings about voltage imbalance and switching loss increment problems. This paper proposes a medium voltage series resonant converter with series-connected SiC MOSFETs. By adding snubber capacitors to each SiC MOSFET and working at LLC resonant soft-switching mode, the voltage imbalance is reduced and switching loss is decreased. Then the analytical model of MVSRC is established. Moreover, the voltage imbalance model is established and the voltage imbalance sensitivity is defined to guide the snubber parameter selections. Afterward a design example of the 99% efficient 5kV/400V prototype is presented. Lastly, the experimental results verify the validity of proposed methods and the accuracy of analysis.