Photovoltaic Power Generation Systems Responsible for Expanding Renewable Energy Use

Photovoltaic Power Generation Systems Contributing to Realization of Low-Carbon Society
KITABAYASHI Masayuki

Trends in Photovoltaic Power Generation Systems and Toshiba's Approach
INABA Michihiko / WATANABE Kenji
Expectations for renewable energy have recently been rising. In particular, the introduction of photovoltaic (PV) power generation systems is expanding both in Japan and overseas. The development of high-efficiency, low-cost PV systems is essential for their widespread dissemination, in addition to the appropriate economic support measures.
Toshiba is promoting the system integrator business for PV systems not only in Japan but also in overseas markets through its Photovoltaic Systems Promotion Division, which was established on January 1, 2009. We offer main components consisting of PV systems, secondary batteries for the stabilization of output fluctuations, maintenance tools, and technologies for interactive operation between PV systems and home energy management systems (HEMS) or smart grid systems.

Mega Solar Systems for Electric Power Utilities
HASEGAWA Yoshiaki / NIIMOTO Takeshi / OWADA Koji
Toshiba is making efforts to disseminate large-capacity photovoltaic (PV) power generation systems, or so-called mega solar systems, through the development of various technologies for electric power utilities. Among the results achieved are the following: (1) reduction in the cost of solar cell array foundations through wind velocity distribution analysis, (2) reduction in the cost of solar cell array frameworks through a structural design review, (3) development of sealed-type packages for power conditioning systems (PCSs) to facilitate the installation of inverters in coastal areas, and (4) functions for system stabilization so as to make mega solar systems more widely available.
We are continuing our efforts to reduce system construction costs through both the standardization of equipment specifications and the development of new construction methods, to promote the further spread of mega solar systems.

Large-Scale Power Conditioning Systems for Photovoltaic Generation Systems in Overseas Markets
AMBO Tatsuaki / IKAWA Eiichi / Ruben INZUNZA
The introduction of renewable energy systems is rapidly expanding worldwide. In particular, projects for large-scale photovoltaic (PV) power plants with a capacity of 10 MW or higher are in progress in various countries.
The Toshiba Group has developed and released a lineup of power conditioning systems (PCSs) for PV generation systems targeted at overseas markets, including 500 kW and 630 kW models compliant with both the International Electrotechnical Commission (IEC) standards and the Golden Sun Certification standards and a 500 kW model compliant with the UL standards. As integrated PV substations, including PCSs, high-voltage interconnection type insulated transformers, and switchgears in outdoor-rated enclosures, are often installed separately in large-scale PV power plants, we have developed and evaluated a prototype 1 MW PV substation. To fulfill the requirements for system interconnection in the North American market, we have confirmed the compliance of the system through utility interconnection tests performed with a full-scale setup.

Verification Tests on Photovoltaic Power Generation System with Output Fluctuation Suppression Function
NAOI Shinya / NORO Yasuhiro / OKUDA Yasuo
The dissemination of large-scale photovoltaic (PV) power generation systems is expected to significantly expand in the future. However, as PV power and other renewable energy sources are affected by weather conditions, their output tends to be unstable. The introduction of large quantities of PV power into an electricity system will therefore cause fluctuations in the output voltage and the frequency.
As a solution to this issue, Toshiba has developed a large-scale PV power generation system equipped with an output fluctuation suppression function using a battery energy storage system. We are now conducting verification tests and have confirmed the effectiveness of the fluctuation suppression function even in the case of large fluctuations in PV output.

Fault Monitoring and Diagnostic System for Photovoltaic Modules
SATO Makoto / NODA Etsuo / WAKAMATSU Kengo / PIAO Ying
To improve the generating efficiency of photovoltaic (PV) power generation systems, demand has risen for technologies that can contribute to the effective operation of PV power plants as well as technologies that can realize high-efficiency PV modules.
Toshiba has developed a fault monitoring and diagnostic system for PV modules incorporating the following technologies to provide comprehensive support for the operation and maintenance of PV systems: (1) an active sensing and monitoring system that can collect detailed data on the performance of PV modules, (2) a data-driven diagnostic system that can detect faults in a system using collected voltage and current data, and (3) an image-based diagnostic system that can identify cells in which a fault has occurred and the causes of failure.

System Integration Framework for Global MW-Class Photovoltaic Power Generation Solution
ISHII Gaku / IWAMASA Mikito / HASEGAWA Yoshiaki
MW-class photovoltaic (PV) power generation systems, or so-called mega solar systems, are increasingly in demand in both the public-sector and industrial markets. PV power generation system integration (hereafter abbreviated as PV SI) is the key to the success of these projects in terms of meeting various requirements for and constraints on such systems, including the geographical and meteorological conditions of the installation site, investment objectives, and so on.
Toshiba has been developing a PV SI framework and an information technology (IT) platform to achieve an accurate and efficient engineering process for such systems. The PV SI framework offers the flexibility to change system configurations and business requirements through a service-oriented architecture (SOA)-based engineering environment and a spreadsheet-like interface to access the SOA-based engineering environment, as well as the ability to calculate the optimal solution by a constraint processing mechanism.

High-Efficiency Inverter Circuit Technology for Residential Photovoltaic Power Conditioning Systems
MOCHIKAWA Hiroshi / TSUDA Junichi / KOYAMA Yushi
Power conditioning systems (PCSs) for residential photovoltaic (PV) systems convert the DC power generated by PV modules into AC power used by home appliances, and are required to be compact with low noise and low heat output. To meet these requirements, demand is increasing for an inverter circuit with high power conversion efficiency even at switching frequencies exceeding the audible frequency range.
To realize compact, high-efficiency, transformerless PCSs, Toshiba has developed both a proprietary inverter circuit technology that achieves a conversion efficiency of 99% at a carrier frequency of 25 kHz, and an electromagnetic interference (EMI) noise suppression technology that can effectively reduce the leakage current and electromagnetic noise generated by high-frequency switching.

Organic Thin-Film Solar Cell Technologies for Realization of Low-Cost and High-Performance Solar Cells
SAITO Mitsunaga / OHKA Haruhi / HOSOYA Masahiro
Photovoltaic (PV) power generation technologies have recently been attracting considerable attention as promising sources of renewable energy. In order to realize efficiency higher than that of conventional solar cells, novel solar cells including compound semiconductor solar cells and quantum dot solar cells are under development. However, silicon-based solar cells are still the mainstream in the PV module market, because novel solar cells pose several problems such as their high manufacturing costs and high costs for the introduction of production equipment such as vacuum apparatus.
Toshiba has been engaged in research and development of both highly efficient organic semiconductor materials and device structures with high photovoltage and photocurrent, and has developed production equipment and a thin-film coating process technology using a meniscus printing method for the production of large-area solar cell modules so as to realize low-cost and high-performance solar cells. Organic thin-film solar cell technologies can offer various applications such as battery chargers for mobile devices, PV modules for home use, building materials, and so on at lower cost, taking advantage of the features of thin films on flexible substrates.

Thin-Film Transistor Using Oxide Semiconductor for Realization of Thin and Lightweight Sheet Display
MIURA Kentaro / UEDA Tomomasa / YAMAGUCHI Hajime
Thin and lightweight sheet displays similar to paper will create dramatic changes in the usage of displays, leading to the realization of thinner and lighter mobile devices, wall-hung TVs that blend into interiors like posters, and so on. The driving capability and stability of thin-film transistors (TFTs) on a plastic substrate are becoming increasingly critical for achieving practical use of sheet displays.
As a solution to this issue, Toshiba has developed an amorphous oxide semiconductor for TFTs processed on a transparent plastic substrate at 200°C. The driving capability and stability of the TFT are more than 10 times higher than those of amorphous silicon (a-Si) TFTs that are commonly used for liquid crystal display (LCD) TVs. We have developed a 3-inch prototype organic light-emitting diode (OLED) sheet display with simultaneously formed integrated gate driver circuits of 1 g in weight and 0.1 mm in thickness except for the driver circuits, and confirmed its practicality.

TMPM370 Microcomputer for Vector Control of Motor Drive Applications Featuring Low Power Consumption
SUZUKI Nobuyuki / HASEGAWA Yukihisa / KOSHIBA Susumu
In order to save energy in air conditioners, refrigerators, washer-dryers, and other home appliances from the standpoint of environmental awareness, demand has recently risen for both a sinusoidal drive technology and a vector control technology to drive motors with high efficiency, low vibration, and low noise. Vector control is being increasingly adopted by Japanese home-appliance manufacturers and is expected to also expand to manufacturers in developing countries.
Toshiba has developed the TMPM370 microcomputer with an embedded vector engine, which is effective in controlling applications requiring a sinusoidal drive. The TMPM370 is user-friendly for designers intending to newly introduce vector control and can reduce the load of software development.

Uncompressed High-Definition Video Signal Transmission Using MHL^TM Technology for Mobile Devices
MATSUMURA Masafumi / ISHIWATA Kayoko / OHURA Kazumasa
Mobile High-Definition Link (MHL) is a high-speed, high-definition (HD) audio and video transmission technology that responds to the needs of the latest mobile devices with high performance and high functionality. MHL makes easy connection possible between mobile devices and digital display devices without hampering the usability of the mobile devices, based on audio and video transmission technologies for conventional digital consumer products. Furthermore, it allows uncompressed HD video signal transmission from a mobile device to a digital TV and simultaneous power feeding to the mobile device.
Toshiba is engaged in the development of new products equipped with MHL technology and is playing a role as a promoter member of the MHL Consortium in order to realize the next-generation MHL specifications.

dynabook_TM Qosmio_TM T851 Glasses-Free 3D AV Notebook PC
SAKAI Akio / NAKAMURA Seiichi / NAGASAWA Norikazu
In response to the wide dissemination of three-dimensional (3D) image contents in recent years, Toshiba has developed the dynabook Qosmio T851 glasses-free 3D audiovisual (AV) notebook PC, which enables users to watch 3D images without the need for dedicated glasses, as the seventh-generation model in the dynabook Qosmio series. The T851 allows users to enjoy 3D contents more comfortably and more naturally through new technologies including 3D window technology, face tracking technology, and 2D to 3D (2D3D) real-time conversion technology, in addition to glasses-free 3D technology. The T851 also features a new decoration technology using in-mold forming (IMF) film with textures for improvement of not only tactile feeling but also fingerprint resistance.

RIANT Graphics Library to Improve Efficiency of Development of 3D GUIs on Embedded Devices
FUKAI Yusuke / Armand GIRIER / NAKANISHI Akira
Embedded devices equipped with graphics processing unit (GPU) chips, such as smartphones, digital televisions, and so on, increasingly feature graphical user interfaces (GUIs) that offer attractive graphics and animation effects. However, it is difficult to efficiently develop such GUIs due to the complex processes involved.
As a solution to this issue, Toshiba has developed the RIANT graphics library for embedded devices to support the development of GPUs, which makes it possible to add two-dimensional (2D) and three-dimensional (3D) animation effects without difficulty. RIANT can improve 3D drawing capabilities and speed by drawing existing 2D widgets through GPU functions, while also maintaining the functionality and portability of 2D GUI toolkits.

Vacuum Interrupter-Type Load Tap Changers
SUGIYAMA Hironori / KAKOKI Osamu / EGUCHI Naoki
On-load tap changers (OLTCs) are used to change the tap of an energized transformer in order to adjust the voltage. As the diverter switch of OLTCs for conventional oil-immersed transformers is subjected to erosion due to arcing in the oil during tap changing operations, oil contaminated by the resultant sludge must be purified by an oil filter and it is necessary to perform inspections and maintenance at regular intervals. Vacuum interrupter-type load tap changers (VI-LTCs) have recently been attracting considerable attention as a solution for the extension of maintenance intervals and operating lifetimes, because the contacts of the vacuum interrupters are not significantly worn away and the oil is only slightly stained.
Toshiba has already developed and released VI-LTCs applicable to oil-immersed transformers of up to the 30 MVA class. We have now newly developed VI-LTCs of intermediate capacity applicable to oil-immersed transformers of up to the 154 kV-100 MVA class.