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Tomoyuki K.,NEC Corp | Yoshinori C.,NEC Communication Systems Ltd. | Kaneaki K.,NEC Communication Systems Ltd. | Tomotaka N.,Takasago Ltd.
NEC Technical Journal | Year: 2010

A submarine cable system is fed power from power feeding equipment that supplies constant current. Such power feeding equipment is expected to enable an ultra-high voltage output to supply power for long-distance submarine cable systems, as well as supporting long-period operations. This paper introduces power feeding equipment for application to NEC's submarine cable systems that achieves compact, high voltage and high reliability characteristics.

Takasago Ltd. and NEC Corp | Date: 2012-11-14

Provided is a power system that can arbitrarily set output power while stabilizing output voltages. Connection terminals 13 and 23 of lower power sources 1 and 2 are connected to external connection terminals 41 in parallel. Voltage measurement section 31 measures voltage values of external connection terminals 41 as measured voltage values. Power converters 12 and 22 measure power supply capacities of lower power sources 1 and 2, respectively. Output instruction section 32 adjusts power or currents flowing through connection terminals 13 and 23 based on the measured voltage values and the power supply capacities so that the measured voltage values are included in a predetermined voltage range.

Ma C.,Shanghai JiaoTong University | Yoshida K.,Takasago Ltd | Honda K.,Takasago Ltd
2015 54th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2015 | Year: 2015

This report discusses using the new SiC-MOSFETs in a front-end DC-DC converter for distributed power systems. In such an application, high efficiency and high power density are the major driving factors that naturally require a high switching frequency. The SiC-MOSFET is widely considered a desirable switching device for the high-frequency power conversion/inversion circuits due to its high voltage, low on-resistance, and fast switching speed. Here a 700-V 40-kW isolated bidirectional resonant LLC DC-DC converter is designed and fabricated using both the conventional Si-IGBTs and SiC-MOSFETs. The experimental results show the DC-DC converter using SiC-MOSFETs can reach a system efficiency around 98%, about 2% higher than that of the DC-DC converter using the conventional Si-IGBTs at rated power. It is also found that high-power and high-frequency transfer such as working at 100 kHz is now not commercially available. The optimized design and fabrication of the high-frequency transformer is crucial to promote the application of SiC-MOSFETs in high-power isolated DC-DC converters. Besides, accurate modeling of the SiC-MOSFET, high-precision simulation of the converter, and cost-performance evaluation/prediction are also important. © 2015 The Society of Instrument and Control Engineers-SICE.

Preparation of battery charging infrastructures is the key to the dissemination of electric vehicles. Some types of EV chargers are already available according to applications. We would like to introduce the need for the CHAdeMO protocol that allows any vehicle to be charged optimally and the functional specifications and technologies applied to the large-capacity EV Fast Charger "TQVC500M3" that features battery recharging at the most rapid rate.

Sugawa M.,TAKASAGO Ltd.
NEC Technical Journal | Year: 2012

EV development test systems are used to test the performance of motors and inverters for hybrid and electric vehicles by simulating the behaviors of the component parts of an electric power train. They are compatible with HILS systems, which simulate an entire vehicle by combining an EV power emulator and a vehicle control simulator. This paper outlines the recent technological advances in EV development test systems and introduces a battery charge-discharge test system.

Nanba M.,TAKASAGO Ltd.
NEC Technical Journal | Year: 2012

The key to realize a low-carbon society is the efficient use of a variety of energy systems. We would like to introduce the functional specifications and technical details of a multi-source power conditioner that combines optimally storage batteries and solar power generation etc.

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