1 Introduction
The "Energy Conservation Technology Strategy" released by Japan's Ministry of Economy, Trade and Industry in April 2008 proposed the following five energy conservation technologies:
(1) Super Combustion System Technology – Improves Combustion Efficiency;
(2) Energy storage technology that transcends time and space;
(3) Energy-saving technologies in the field of information-based social life;
(4) Advanced energy-saving technologies for transportation;
(5) Adopt power electronic energy-saving technology.
Among these measures, power electronics technology is listed as one of the five key energy-saving technologies, thus confirming its important position in the energy-saving technology strategy. This technology can improve the energy utilization efficiency of numerous electromechanical devices to achieve energy conservation.
2. Development Plan for New Power Electronic Devices and Their Applications
In addition to current energy-saving technologies based on silicon as the core component, novel power electronic devices and equipment such as SiC (silicon carbide) and GaN (gallium nitride) are expected to achieve industrial application, which will bring innovative technological breakthroughs for future development. Compared with Si, SiC and GaN devices can reduce losses. Their applicable fields differ depending on the ease of crystal growth, cost, and thermal conductivity. GaN is suitable for high-frequency, medium-voltage applications, while SiC is suitable for high-voltage, high-current applications.
(1) It has been reported that various power conversion devices using SiC devices can improve efficiency by about 2-10% (depending on the load condition) in the transportation industry such as hybrid vehicles and electric vehicles, improve efficiency by 4-5% in computer power supplies, and are expected to improve efficiency by about 2% in water pump and fan motor drives. In the power field, power loss can be significantly reduced.
SiC power devices have only seen breakthroughs in recent years, and there is still much room for improvement in device manufacturing technology, such as the stable growth of epitaxial layers and the cost reduction of large-diameter, high-quality wafers. Secondly, it is also necessary to establish process technologies for manufacturing high-efficiency devices and solve peripheral technical issues such as packaging for higher operating temperatures, soft switching, and high-frequency countermeasures.
(2) Regarding GaN, it is expected that it will have higher operating frequency power devices than SiC, and be applicable to fields such as communication, power conversion, aviation, and aerospace.
(3) Gemstone devices are also known as more ideal devices, and the United States and Japan are conducting research and development on them.
In terms of device manufacturing, Japan has proposed three indicators: ① larger wafer diameter; ② lower wafer defect rate, i.e., reducing dislocation density; ③ lower on-resistance and improve withstand voltage.
The planning indicators and schedule are shown in Figure 1.
(4) Application device
• To expand the application of power electronics technology, Japan has set a goal of increasing the power density of power conversion devices, with specific objectives including:
10W/CC in 2010, 50W/CC in 2017, and 100W/CC in 2025.
• High-efficiency inverters: Yaskawa Electric of Japan has developed SiC inverters, and its future development goals are: ① ultra-low loss SiC switching elements (normally off type MOSFETs); ② improve inverter design technology.
3. New power electronic devices will expand their application areas.
Competition among Japan, the US, and Europe in technological development is fierce. In the substrate wafer market, some companies hold a monopoly, while Japan leads in process technology, device technology, and packaging technology. To gain international competitiveness in power electronics technology, Japan plans to leverage its strengths, investing capital, equipment, and human resources through corporate conglomerates, forming networks with relevant parties to effectively advance technological development. Combined with technological development, it will promote the dissemination and adoption of results aligned with international standards.
(1) According to Japan's "Energy Conservation Technology Strategy 2008", the main areas for the promotion and application of power electronic devices and their applications are as follows:
SiC devices are currently used in large power equipment, industrial equipment, distributed power sources, home appliances, information equipment, IGBTs to reduce losses, and high-speed railway traction power systems.
• SiC and GaN devices: From 2012 to 2015, their applications gradually became widespread in the following fields:
①SiC power devices/inverters:
Home appliances, distributed power sources, industrial equipment, automobiles and hybrid electric vehicles (HEV), electric vehicles (EV), switching components, electric locomotives, low-voltage electrical appliances for power distribution, and information equipment (rectifier components).
②GaN power devices/inverters
Home appliances, distributed power sources, radio ground stations (switching components), vehicle radar, and information equipment (rectifier components).
③ Gemstone components: to be used in information equipment and low-voltage power distribution instruments after 2020.
(2) With the improvement of device performance, the application areas will expand to:
With high-density packaging of power devices, modularization of systems, and mechatronics integration, they are mainly used in high-voltage power supplies and power supplies for information equipment.
With increased current density, it is mainly used in general-purpose inverters and hybrid electric vehicles (HEVs).
With its high heat resistance and high frequency operation, the device is mainly used in radar, communication base stations, and mobile phone base stations.
• Improved soft switching, matrix converters, EMI and communication technologies are mainly used in power systems and high-speed railway traction systems.
Low-loss high-frequency devices (HFETs for switching) are mainly used in power supplies, home appliance inverters, and general-purpose inverters.
(3) Develop supporting and related technologies for the application of related devices:
• Home Energy Management System (HEM);
• Building Energy Management System (BEMS);
• Regional Energy Management System (LEMS).
For details, please click: Development Plan for New Power Electronic Devices in Japan's Energy-Saving Technology Strategy
