TOSHIBA REVIEW
Vol. 74, No. 1, January 2019

  Special Reports 1

Green Energy Aggregation Cultivated by Toshiba for Effective Utilization of Renewable Energy

Toshiba’s Technologies for both Using Renewable Energy as Major Power Source and Stabilizing Electricity Supply and Demand
SASAKI Takashi

Toshiba’s Approaches to Green Energy Aggregation Service Contributing to Stabilization of Power Systems
KOSAKADA Masayuki / NAKAI Akimasa / FUJITSUKA Shinya
Power generation systems utilizing renewable energy sources with no carbon dioxide emissions, also known as green energy systems, are expected to be widely introduced as a countermeasure against global warming. Such systems include solar photovoltaic (PV), wind power, and other systems. However, as these systems are affected by weather conditions, their output tends to be unstable. In this context, attention is being increasingly focused on green energy systems stabilized by the use of battery energy storage systems that can store surplus generated power. To increase the usability of green energy, new services utilizing information and communication technologies (ICTs) connecting the storage batteries of electricity users and various distributed energy resources, including demand response (DR), virtual power plants (VPPs), and the energy resource aggregation business (ERAB) employing DR and VPPs, have become widely disseminated. Various other technologies are also required in order to connect large amounts of electricity supplies utilizing renewable energy sources while maintaining the stable supply and demand of electric power systems.
The Toshiba Group is engaged in research and development aimed at facilitating the provision of a green energy aggregation service with high environmental value by integrating technologies for renewable energy power generation, VPP, and electric power systems.

Latest Technologies for Solar PV Power Generation Systems
YABUI Ken / SADAMASA Akira / MIYAUCHI Hiroyuki
With the ongoing introduction of solar photovoltaic (PV) power generation systems following the enforcement of the Feed-In Tariffs (FIT) Act, the construction of new PV power plants is becoming difficult because of decreasing tariff rates as well as restrictions on connections to the power grid and on the shape of construction sites, resulting in increased demand for engineering and construction techniques in order to solve these problems. On the other hand, in response to growing concern over the reduction of carbon dioxide emissions, self-consumption type PV power generation systems, in which all electricity generated by a company is consumed in the company’s own facilities without using the FIT scheme, have been increasingly installed in recent years.
With these trends as a background, the Toshiba Group is promoting the development of the latest technologies for PV power generation systems. These include (1) efficient construction techniques using information and communication technologies (ICTs), (2) an output fluctuation suppression technology for PV power generation systems equipped with a battery energy storage system, and (3) a simulation technology to derive the optimal capacity of solar cell modules and a control technology to prevent surplus power generation for self-consumption type PV power generation systems.

Latest Technologies for Wind Turbine Systems
TANIYAMA Yoshihiro / YAMADA Toshimasa / OGASAWARA Kento
Technological innovations have been progressing in the field of wind turbine systems, one of the renewable energy systems aimed at achieving a decarbonized society. Among these innovations is increased single-unit capacity, as well as preventive maintenance through analysis of data collected from Internet of Things (IoT) devices.
Toshiba Energy Systems & Solutions Corporation has been promoting wind power generation business activities, mainly in Japan, since entering the market in 2010. We have been continuously working on the improvement of wind turbine generators (WTGs) in compliance with domestic regulations and guidelines as well as on the domestic production of several WTG components. We have also developed and introduced various techniques, as follows: (1) development of a technique for precise evaluation and diagnosis of wind conditions, even in mountainous areas with complex terrain, employing both large-scale computational fluid dynamics (CFD) analysis and wind resource analysis software; (2) development of proprietary equipment to achieve a method for single-blade construction at small worksites; and (3) enhancement of the performance of WTGs and their compatibility with power systems based on rotating machine technologies and control technologies cultivated through our thermal and hydroelectric power generation businesses. We are steadily working toward the realization of WTGs appropriate to the Japanese environment based on knowledge accumulated through construction and operation using these techniques.

Portfolio Management Technology to Select Optimal Combination of Electricity Users for Negawatt Aggregation Services
KUSAKIYO Kazuaki / OTSUKI Tomoshi / MATSUZAWA Shigeo
The tightening of the electricity supply and demand has become a matter of serious concern in recent years due to power fluctuations of renewable energy systems such as solar photovoltaic (PV) power systems and climate changes such as intense heat of summer. In this context, negawatt aggregation services have been introduced in Japan to balance electricity supply and demand by trading the electricity shaved by electricity users, or so-called negawatts, in response to the requirements of electric power companies. In order to maximize the effect of negawatt trading, it is essential for aggregators to select the optimal combination of multiple electricity users taking into consideration seasonal and daily variations and the operating conditions of their equipment.
The Toshiba Group has developed a portfolio management technology to select the optimal combination among a plurality of electricity users by precisely grasping the amount of negawatt power of individual users. We have evaluated the effect of our technology by using data that we have accumulated from past demand response (DR) events and confirmed that this technology achieves an increase in the amount of negawatt power.

Charge and Discharge Planning Technique for Multipurpose Utilization of Storage Batteries of Electricity Users
MURAI Masahiko / SAKAMOTO Tatsuro
In electricity markets, the energy resource aggregation business (ERAB) is expected to contribute to the stability of electric power systems through utilization of the energy sources of electricity users controlled by aggregators by means of virtual power plants (VPPs) and demand response (DR) services. In particular, storage batteries with flexible operability are suitable for the ERAB.
To realize effective utilization of the storage batteries of electricity users, the Toshiba Group has developed a storage battery charge and discharge planning technique for multipurpose use. This makes it possible to not only provide individual electricity users with services featuring a business continuity plan (BCP) function in the event of an emergency as well as peak shaving and shifting functions based on demand forecasts, but also to offer optimal services at the time of DR targeting all electricity users. We have conducted simulation tests and confirmed that this technique offers multiple services including DR services by ensuring sufficient surplus power of aggregated storage batteries in a scheduled period of DR.

Technologies for O&M Services Supporting Introduction of Renewable Energy Generation Systems
MIZUNO Hiroshi / KOISO Takashi / MIMURA Yuki
Renewable energy systems including solar photovoltaic (PV) power generation and wind turbine systems have established an enhanced presence in the Japanese electricity market. With the growing number of such power plants installed in locations throughout Japan, attention has been increasingly focused on remote monitoring solutions to support operation and maintenance (O&M) services for their equipment using various observation data collected by sensors and measuring instruments, or so-called smart maintenance.
In order to provide O&M services for PV power generation and wind turbine systems, the Toshiba Group is promoting the development of technologies to realize remote monitoring systems using cloud services. We have developed a solution for PV power generation systems that can detect a decrease in power generation performance and automatically identify the cause, as well as a total solution aimed at improving the efficiency and availability of wind turbine systems.

Tandem Solar Cell Combining Transmission Type Cu2O Solar Cell with Si Solar Cell to Achieve High Efficiency and Low Cost
YAMAMOTO Kazushige / SHIBASAKI Soichiro / NAKAGAWA Naoyuki
Attention is being focused on transmission type Cu2O solar cells made from cuprous oxide (Cu2O), which can be obtained using abundantly available materials and is able to transmit red and infrared light, as a promising candidate for solar photovoltaic (PV) generation. A Cu2O solar cell laminated on a silicon (Si) solar cell is expected to achieve high efficiency through the conversion of light with a wider range of wavelengths into electric energy.
Toshiba has been developing a tandem solar cell composed of a transmission type Cu2O solar cell laminated on a dominant crystalline Si solar cell with high efficiency and low cost as a key device for ultrahigh-efficiency solar PV generation that can achieve high electricity output even in a limited area. We have confirmed through simulations that this tandem solar cell achieves an ideal efficiency exceeding 30%. Applying our proprietary thin-film fabrication techniques, we have also succeeded for the first time in the world in forming an electricity-generating transmission type Cu2O solar cell on a transparent electrode, and have fabricated a prototype tandem solar cell using this Cu2O solar cell.

   

  Special Reports 2

Optimal Solutions for Water and Environmental Systems

Making Efforts to Ensure Sustainability of Water Supply and Sewerage Businesses
TAKIZAWA Satoshi

Solutions Contributing to Construction of Flexible and Sustainable Water and Environmental Systems
TONOZUKA Yoshikazu
A noticeable deterioration in water and environmental systems has recently been occurring in various countries, particularly in developing countries in the Asian and African regions, concurrently with population growth and rapid urbanization and industrialization. In this context, the Sustainable Development Goals (SDGs) were adopted by the United Nations General Assembly in 2015 as a global movement toward environmental conservation through international cooperation. In Japan, on the other hand, water supply and sewerage businesses have been facing problems in maintaining business continuity, including a shortage of human resources, aging facilities, and deteriorating financial conditions. To overcome these problems, it is necessary to make best use of the limited resources available by securing human resources, ensuring the inheritance of accumulated technologies, further improving service operations, and offering efficient operation and maintenance (O&M) services.
For the realization of strong water and environmental systems and achievement of the SDGs, the Toshiba Group is offering a wide variety of solutions utilizing information and communication technologies (ICTs) that flexibly and economically respond to issues in water and environmental systems appropriate to each life-cycle stage of individual water supply and sewerage companies.

Solutions Utilizing TOSWACS Integrated Platform to Achieve Automation of Water Supply and Sewerage Plant Operation
YOKOYAMA Suguru / MATSUDA Hiroaki / MATSUMOTO Jun
The need has arisen in recent years for water supply and sewerage businesses in Japan to achieve high efficiency due to the advantages of scale through the promotion of consolidation and cooperation, as well as to improve the efficiency of their business processes for operation and maintenance through the introduction of innovative technologies.
In response to customers’ requirements, the Toshiba Group has been supplying solutions that contribute to the automation of water supply and sewerage plant operation. These solutions, applying the TOSWACS integrated platform composed of monitoring and control technologies based on our long accumulation of development experience and information and communication technologies (ICTs), together with the latest technologies for optimization, visualization, and diagnosis, achieve reductions in the number of operators required for operation and maintenance while also reducing various other costs associated with plant operation.

Advanced Control Solutions Using Automation Techniques for Optimal Operation of Water Supply and Sewerage Facilities
HIRAOKA Yukio / YAMANAKA Osamu / ARIMURA Ryoichi
Water supply and sewerage facilities are currently confronting the need for improved efficiency of maintenance and management work using a smaller number of operators while suppressing plant operation costs including electric power and chemical costs.
In keeping with this trend, the Toshiba Group has been developing a broad array of automation techniques that can optimize the operations of water supply and sewerage facilities by applying information and communication technologies (ICTs). The use of these automation techniques has achieved the minimization of costs and environmental loads while securing the necessary water quality and water treatment capacity to meet demand by applying various approaches in addition to the conventional optimal control law and optimization techniques. We are committed to delivering advanced control solutions in order to realize optimal plant operations using these automation techniques for each process as well as the overall system.

Solutions to Improve Efficiency of Operation and Maintenance of Water Supply and Sewerage Facilities
HOKARI Hiroyuki / KUDO Yasutaka / MATSUMOTO Haruki
To realize sustainable water supply and sewerage businesses, various problems must be overcome including a lack of experienced personnel, the need for renewal of aging facilities, and decreasing income from water-related services. In order to surmount such problems, it is necessary for these business entities to improve the efficiency of their business processes through the introduction of innovative technologies.
In response to these requirements, the Toshiba Group has been working on the improvement of operational efficiency in each phase of the life cycle of water supply and sewerage facilities utilizing innovative technologies including information and communication technologies (ICTs). In the operation and maintenance phases, we ensure highly efficient operation of water purification plants by determining recommended chemical injection ratios utilizing the customer’s own know-how, based on analyses of process data accumulated by their monitoring and control system. We also apply measuring instrument data obtained by means of ICTs so as to gain an understanding of facility conditions and make preliminary diagnoses at the time of periodic inspections. Utilizing our experience and expertise in this field, we are making continuous progress in offering quick and optimal solutions tailored to the on-site requirements of individual customers while further improving the efficiency of their operation and maintenance.

Solutions for Water Supply and Sewerage Businesses Adapted to Various Public-Private Partnerships
MIYAO Keiichi / TAKEDA Satoshi / KOMINE Hideaki
In order to solve issues faced by water supply and sewerage businesses, including the shortage of human resources, aging facilities, and deteriorating financial conditions, the diversification of public-private partnerships (PPPs) has been progressing in Japan in recent years. This has resulted in many changes in business configurations, such as the establishment of public-private investment companies, the outsourcing of comprehensive maintenance and management operations encompassing both water supply and sewerage systems, and the introduction of concession contracts.
With these circumstances as a background, the Toshiba Group has been engaged in the development of technologies and solutions for the optimal operation of water supply and sewerage systems through expansion of the framework of PPPs from operation and maintenance (O&M) services to comprehensive outsourcing services and delegation of water services to third parties. Our objective is to provide higher value compared with the conventional forms of operation and to contribute to the realization of strong and sustainable water supply and sewerage businesses.

Solutions for Realization of Wastewater Recycling Plants with Higher Efficiency
NAKAMURA Kensuke / KAKINUMA Kenji / IDANI Tatsuya
As a consequence of the increase in both household and industrial water consumption in the Asian and African regions accompanying their economic development, water shortages have become a matter of serious concern in recent years.
To address this issue, the Toshiba Group has been engaged in the introduction of wastewater recycling plants to countries in these regions. From the viewpoint of efficient use of water, we have developed a solution that makes it possible to achieve high water recovery rates by means of a treatment process that suppresses the clogging of reverse osmosis (RO) membranes so as to secure sufficient supplies of recycled water. From the viewpoint of maintaining the treatment performance of plants, on the other hand, we have developed a solution to ensure stable plant operation by offering operation and maintenance (O&M) services that can remotely control individual facilities in accordance with constantly changing wastewater conditions based on various collected data. In addition to these solutions, we are aiming to further improve the efficiency of wastewater recycling plants through the practical application of high-concentration technologies and the use of cloud systems.

   

  Feature Articles

TMPM4K Motor Control Microcomputer for High-Performance PMSM Drive Systems at Lower Cost
MAEKAWA Sari / SUZUKI Nobuyuki / NIWA Ryota
Permanent magnet synchronous motors (PMSMs) have become widely disseminated in the consumer and industrial fields in recent years. Progress has been made in enhancing the performance of PMSM drive systems through the introduction of vector control to secure high efficiency while reducing noise. However, the application of vector control to PMSM drive systems is hindered by issues associated with increased costs. These costs arise due to either the necessity for expensive sensors including current sensors and position sensors for vector control, or the necessity for advanced technology on the user’s side if a sensorless control method for PMSM is employed in order to eliminate the requirement for expensive sensors.
In response to users’ needs for the easy introduction of vector control into motor drive systems, the Toshiba Group has been developing and supplying motor control microcomputers that feature a vector engine (VE) incorporating certain vector control functions as hardware. We have now commercialized the TMPM4K, a motor control microcomputer suitable for PMSM drive systems equipped with an improved VE and an advanced programmable motor driver (A-PMD) to generate inverter control pulse signals. The TMPM4K is expected to offer high performance due to increased processing speed while reducing costs due to the smaller number of parts required.

Demand Forecasting Technology Using AI for On-Demand Ridesharing Services
IRIMOTO Yuji / UEDA Hiroki / ITO Hidemasa
With the aim of constructing next-generation mobility systems in Japan, both the public and private sectors are moving forward with projects to introduce on-demand ridesharing services as efficient and low-cost transportation systems that can overcome the difficulties faced by the transportation sector in recent years accompanying the shift to an aging society with fewer children. To efficiently operate these systems, however, demand forecasting is essential in accordance with the various needs of users in each local community including the embarkation and disembarkation points, desired times, and frequency of operation.
Toshiba Digital Solutions Corporation, in cooperation with Junpuzi Co., Ltd., has developed a demand forecasting technology using artificial intelligence (AI) based on the results of learning and analysis of operation data and external environment data including weather data accumulated by Junpuzi Co., Ltd. over a period of about nine years. This technology makes it possible to forecast embarkation and disembarkation points and times and the number of users, and to display this information on a map according to the variations in reservation data, thereby allowing the operation schedule to be optimized. Demonstration experiments on on-demand ridesharing systems in 20 areas were inaugurated in July 2018.

LED Dimming System Composed of DC LED Bulbs and DC Dimmer for Rendering of Lighting Spaces
SAITO Yasuhiro / ITAMI Kazuaki
Halogen lamps commonly used as dimmable lighting in theaters and hotel banquet halls are dimmed by means of a phase-cut dimmer. When existing halogen lamps are replaced with light-emitting diode (LED) bulbs for energy saving, however, certain issues may be encountered. These are the frequent occurrence of flickering caused by malfunctions of the phase-cut dimmer when dimming LED bulbs using the existing dimmer, and the difficulty of continuously controlling the fade-in and fade-out conditions of LED bulbs.
In order to resolve these issues, Toshiba Lighting & Technology Corporation has developed an LED dimming system composed of LED bulbs operated with a DC supply and a dedicated DC dimmer. This LED dimming system has a configuration that allows the use of existing lighting fixtures and wiring by replacing the phase-cut dimmer with the DC dimmer, and the halogen lamps with DC LED bulbs. This system provides a flicker-free dimming function equivalent to that of conventional lighting systems using halogen lamps.

   

  Frontiers of Research & Development

“PGSpider” Distributed Data Search Framework Allowing High-Speed Retrieval of Data Stored in Edge Devices

* Company, product, and service names appearing in each paper include those that are trademarks or registered trademarks of their respective companies.