Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

https://ieeexplore.ieee.org/ielaam/41/8031005/7815312-aam.pdf

Review of Silicon Carbide Power Devices and Their Applications

This paper contributes to the steady-state analysis of the bidirectional dual active bridge (DAB) dc-dc converter by proposing a new model that produces equations for rms and average device currents, and rms and peak inductor/transformer currents. These equations are useful in predicting losses that occur in the devices and passive components and aid in the converter design. An analysis of zero-voltage switching (ZVS) boundaries for buck and boost modes while considering the effect of snubber capacitors on the DAB converter is also presented. The proposed model can be used to predict the converter efficiency at any desired operating point. The new model can serve as an important teaching-cum-research tool for DAB hardware design (devices and passive components selection), soft-switching-operating range estimation, and performance prediction at the design stage. The operation of the DAB dc-dc converter has been verified through extensive simulations. A DAB converter prototype was designed on the basis of the proposed model and was built for an aerospace energy storage application. Experimental results are presented to validate the new model for a 7 kW, 390/180 V, 20 kHz converter operation and the ZVS boundary operation.

High-Power Bidirectional DC–DC Converter for Aerospace Applications

Aiming for converters with high efficiency and high power density demands converter topologies with zero-voltage switching (ZVS) capabilities. This letter shows that in order to determine whether ZVS is provided at a given operating point, the stored charge within the mosfet s has to be considered and the condition $L I^2 \geq 2Q_\text{oss} V_\text{DC}$ has to be fulfilled. In the case of incomplete soft switching, nonzero losses occur which are analytically derived and experimentally verified in this letter. Furthermore, the issue of nonideal soft-switching behavior of Si superjunction mosfet s is addressed.

ZVS of Power MOSFETs Revisited

This study deals with the optimal control of hybrid energy storage systems for electric vehicle applications. These storage systems can capitalize on the high specific energy of Lithium-Ion batteries and the high specific power of modern ultracapacitors. The new predictive algorithm uses a state-based approach inspired by power systems optimization, organized as a probability-weighted Markov process to predict future load demands. Decisions on power sharing are made in real time, based on the predictions and probabilities of state trajectories along with associated system losses. Detailed simulations comparing various power sharing algorithms are presented, along with converter-level simulations presenting the response characteristics of power sharing scenarios. The full hybrid storage system along with the mechanical drivetrain is implemented and validated experimentally on a 500 W, 50 V system with a programmable drive cycle having a strong regenerative component. It is experimentally shown that the hybrid energy storage system runs more efficiently and captures the excess regenerative energy that is otherwise dissipated in the mechanical brakes due to the battery's limited charge current capability.

Predictive Algorithm for Optimizing Power Flow in Hybrid Ultracapacitor/Battery Storage Systems for Light Electric Vehicles

A switched-capacitor bidirectional dc–dc converter with a high step-up/step-down voltage gain is proposed for electric vehicles with a hybrid energy source system. The converter presented has the advantages of being a simple circuit, a reduced number of components, a wide voltage-gain range, a low voltage stress, and a common ground. In addition, the synchronous rectifiers allow zero voltage switching turn-on and turn-off without requiring any extra hardware, and the efficiency of the converter is improved. A 300 W prototype has been developed, which validates the wide voltage-gain range of this converter using a variable low-voltage side (40–100 V) and to give a constant high-voltage side (300 V). The maximum efficiency of the converter is 94.45% in step-down mode and 94.39% in step-up mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.

/pdf/a-switched-capacitor-bidirectional-dc-dc-converter-with-wide-4fru054evl.pdf

A Switched-Capacitor Bidirectional DC–DC Converter With Wide Voltage Gain Range for Electric Vehicles With Hybrid Energy Sources

An electric scooter is a promising solution to the global warming problem due to its high driving efficiency and carbon-free drive by electric power from renewable energy. It is a problem that their widespread use is limited by the time and effort required to recharge them. This paper proposes a new Dynamic Wireless Power Transfer EDLC scooter system with 5×2 multi-coils feeding and Si C-VM OSFET single-ended inverters. An EDLC energy storage unit allows many charges of the stepping-stone type Dynamic-Wireless Power Transfer. Transfer power can be small despite the large amount of energy by the 5×2 multi-transfer coil power feeding system. The developed single-ended inverter with a new V-trench SiC-MOSFET is small-size, light-weight, and low-cost. It can operate stably against extreme fluctuations of load by running through power-feeding stations.

A New Prototype of Dynamic WPT Charging EDLC Scooter System with 5×2 Multi-Transfer Coils and SiC-VMOSFET Single-Ended inverters

This paper discusses the bidirectional Wireless Power Transfer (WPT) device for vehicle-to-house (V2H). It uses a simple, compact single-ended converter and self-synchronized phase-difference control mechanism. This paper proposes a way whereby phase difference control could be self-contained on the slave side without mutual communication. This method allows for high-power wireless transmission despite the low coupling coefficient between the transfer coils. The phase difference and transmission power can be altered by changing the MOSFET conduction time on one side without synchronizing the phases on both sides.

A Dual-Active Single-Ended Wireless V2H System with Self-Synchronized Phase-Difference Control Method

Open H-Bridge Topology-based Edge-Resonant Zero Current Soft-Switching PWM-Controlled Bidirectional DC-DC Converter

可変誘導性リアクタンス機能を持つ5エレメント多重共振形DC-DCコンバータ;可変誘導性リアクタンス機能を持つ5エレメント多重共振形DC-DCコンバータ;A Five-Element Multiplex Resonant Full-Bridge DC-DC Converter with a Variable Inductive Reactance

A novel step-up dc-dc converter is presented in this paper, which is suitable for obtaining a high dc-dc voltage ratio. The proposed dc-dc converter features the snubberless zero current soft-switching (ZCS) commutation with MHz high frequency driving of GaN-HEMT by adopting quasi resonance and dual parallel load resonance; multi-resonant while minimizing the number of semiconductor power devices. The circuit configuration and operation principle are described together with briefing the switch-mode transitions. A frequency-domain analysis is provided on the basis of the equivalent circuit, and the design guideline is revealed. The essential performances of the proposed dc-dc converter are demonstrated by experiment of 1-2 MHz / 120 W prototype.

Tomokazu Mishima

Papers

A New Prototype of Dynamic WPT Charging EDLC Scooter System with 5×2 Multi-Transfer Coils and SiC-VMOSFET Single-Ended inverters

A Dual-Active Single-Ended Wireless V2H System with Self-Synchronized Phase-Difference Control Method

Open H-Bridge Topology-based Edge-Resonant Zero Current Soft-Switching PWM-Controlled Bidirectional DC-DC Converter

可変誘導性リアクタンス機能を持つ5エレメント多重共振形DC-DCコンバータ;可変誘導性リアクタンス機能を持つ5エレメント多重共振形DC-DCコンバータ;A Five-Element Multiplex Resonant Full-Bridge DC-DC Converter with a Variable Inductive Reactance

MHz-Driving Current-Fed Snubber-less ZCS Multi-Resonant DC-DC Converter with High Step-Up Voltage Ratio