Kazuaki Mino

Comparative evaluation of three-phase high-power-factor AC-DC converter concepts for application in future More Electric Aircraft

A passive 12-pulse rectifier system, a two-level, and a three-level active three-phase pulsewidth-modulation (PWM) rectifier system are analyzed for supplying the dc-voltage link of a 5-kW variable-speed hydraulic pump drive of an electro-hydrostatic actuator to be employed in future More Electric Aircraft. Weight, volume, and efficiency of the concepts are compared for an input phase voltage range of 98-132 V and an input frequency range of 400-800 Hz. The 12-pulse system shows advantages concerning volume, efficiency, and complexity but is characterized by a high system weight. Accordingly, the three-level PWM rectifier is identified as the most advantageous solution. Finally, a novel extension of the 12-pulse rectifier system by turn-off power semiconductors is proposed which allows a control of the output voltage and, therefore, eliminates the dependency on the mains and load condition which constitutes a main drawback of the passive concept.

A gate drive circuit for silicon carbide JFET

In this paper, a gate drive circuit for a 1300 V/4 A SiC-JFET is proposed and evaluated experimentally for a switching frequency of 200 kHz. Furthermore, a comparison of the switching behavior of a SiC-JFET/Si-MOSFET cascode and of the SiC-JFET driven by the proposed gate drive circuit is shown.

Design, Modeling, and Improvement of Integrated EMI Filter With Flexible Multilayer Foils

Integrated electromagnetic interference (EMI) filter design method with flexible multilayer (FML) foils is presented. An analysis model for integrated EMI filter with FML foils, distributed electromagnetic component (DEMC) model, is proposed. The DEMC model is verified by the experiment. In addition, method to improve the high-frequency performance of integrated EMI filter is investigated. Prototype of integrated EMI filter with FML foils is made for 1 kW switching power supply. In comparison with the traditional discrete EMI filter, it can reduce total volume by 45%.

Integrated EMI filter design with flexible PCB structure

A novel integrated EMI filter structure is proposed in this paper, based on the flexible PCB integrated L-C winding. By employing this integrated L-C structure, CM inductors, DM inductors and CM capacitors are integrated in a single unit. By compare with the planar PCB winding that used in previously proposed method for integrated EMI filters, we found that flexible PCB winding need less length, which means less loss and room. A prototype was built, and measurement result presented.

A Zero Voltage Switching SVM (ZVS–SVM) Controlled Three-Phase Boost Rectifier

A zero voltage switching space vector modulation (ZVS-SVM) controlled three-phase boost rectifier is proposed. A branch composed of one active switch, one resonant inductor and one clamping capacitor is added to the six-switch boost rectifier. In addition, a ZVS-SVM for the rectifier is proposed. It can effectively suppress the reverse recovery process of the bridge switch anti-parallel diodes. All the switches are turned on under zero voltage condition, thus the switching loss is reduced, and electromagnetic inference can be lowered. The switching frequency of the rectifier is fixed. The auxiliary switch works at the same frequency with other switch. All the switches in the rectifier have lower voltage stress. A digital signal processor controlled 4-kW prototype is built to verify the theory

Novel hybrid 12-pulse boost-type rectifier with controlled output voltage

Novel hybrid 12-pulse line interphase transformer (LIT) rectifier systems with integrated single-switch or two-switch boost-type output stage that ensure a constant output voltage independent of mains and load conditions are proposed for supplying actuators of future more electric aircraft. The principle of operation, the dimensioning, and the system control are discussed. The theoretical considerations are experimentally confirmed for a 10 kW laboratory prototype. Finally, the single-and the two-switch system are comparatively evaluated concerning the level of input current ripple, power factor, and overall efficiency.

Ultra compact three-phase rectifier with electronic smoothing inductor

This paper describes the practical realization of an electronic smoothing inductor (ESI) topology, which can reduce the harmonic current level, the output voltage ripple, and the volume of diode bridge rectifiers with a low realization effort. The control strategy and an EMI filtering concept for the ESI are presented and are verified by numerical simulation and experimental results for steady state and dynamic operation. By using the ESI a power density of 7.9 kW/dm/sup 3/ for a 5 kW rectifier prototype is realized. Furthermore a high efficiency of 98.6% and an improved power factor of 0.956 is obtained.

Utilizing Flexible Printed Circuit Board (FPCB) to realize passives integration in LLC resonant converter

There are altogether four passive components in the resonant tank of LLC resonant converter: the series resonant inductor, the resonant capacitor, the parallel inductor and the transformer. A new method utilizing the flexible printed circuit board (FPCB) to realize passives integration in LLC resonant converter is presented. The design process is provided, and the experimental results verify its feasibility. However, due to the severe high frequency loss of the dielectric material used in FPCB technique, the converter efficiency decreases greatly at heavy load condition after the resonant capacitor is integrated, and the switching frequency range to realize output voltage regulation against load variation also becomes wider. We use another two kinds of dielectric material with better characteristic replace the substrate dielectric material in FPCB technique, then the efficiency improves and the switching frequency range shrinks. As a result, the fully integrated structure can reduce the total passive components size by 36% compared to the discrete structure with even better performance. Hence the power density is increased remarkably.

An integrating structure of EMI filter based on interleaved flexible multi-layer (FML) foils

A novel integrated EMI filter structure is proposed in this paper, based on FML foils. It integrates common mode inductors and differential mode capacitors and inductors into a single unit. A novel interleaved flexible multi-layer (FML) foil structure is proposed to overcome the difficulty of enlarging the DM capacitance. A prototype is constructed based on this concept and was put into a front-end converter to replace a discrete EMI filter. Testing result presented.

Impact of dielectric material on passive integration in LLC resonant converter

In this paper, a transformer structure integrating three resonant tank components C_s, L_s, and L_p of the LLC resonant converter is proposed and implemented. For the structure, the analysis and calculation of C_s as well as the calculation and design of L_s and L_p is introduced in detail. In the verification experiments, two kinds of dielectric materials are applied. They result in different performances. The experimental results include the efficiency, the switching frequency, and the temperature rise.