Fuji Electric Review
Vol.70-No.4,2024
Power Semiconductors to Achieve a Decarbonized Society
Power Semiconductors to Achieve a Decarbonized Society
Global efforts are expanding to reduce greenhouse gas emissions, the primary driver of global warming. As a company that is committed to its role in achieving the Sustainable Development Goals (SDGs) through energy and environment businesses, Fuji Electric, in line with its corporate philosophy, which embodies our drive to “contribute to prosperity,” “encourage creativity,” and “seek harmony with the environment,” is focused on creating new products and technologies to contribute to the decarbonization of society. This special issue focuses on power semiconductors, which are essential devices in efforts to decarbonize society, showcasing new products designed for automobile electrification and the adoption of renewable energy sources such as solar and wind power, as well as new technologies developed to enhance the efficiency and reliability of power electronics equipment.
FUJITA, Hideaki
ONISHI, Yasuhiko; MIYASAKA, Tadashi; IKAWA, Osamu
To reduce greenhouse gas emissions through the introduction of renewable energy sources, such as solar and wind power generation; electrification of automobiles; and increased efficiency in power electronics equipment, there are growing expectations for power semiconductors as key devices. Their representatives include insulated gate bipolar transistors (IGBTs) and metal-oxide-semiconductor field-effect transistors (MOSFETs) that use silicon carbide (SiC). Centering on these two devices, Fuji Electric offers products that meet the needs for higher efficiency, greater miniaturization, and increased reliability. We are also working on developing high voltage vertical GaN-MOSFETs and technologies to increase product durability in corrosive environments.
KAMIYA, Masahide; ARAI, Nobuhide; ADACHI, Shinichiro
The electrification of automobiles is moving forward to reduce greenhouse gas emissions. This transition applies not only to large vehicles but also compact and small vehicles. Accordingly, Fuji Electric has developed the “M682” IGBT module, which is suitable for 50- to 100-kW class motor output capacities of light and compact vehicles. The cooler has a direct liquid cooling structures that directly cool the Cu base plates, and the optimized shape and arrangement of its ribs provided in flow paths allow the module to deliver compact sizes, low pressure losses, and low thermal resistance. The module, which has been downsized by 10%, can be used for motors with an output capacity of 50, 75, and 100kW, depending on the combination of a cooler and a chip, even with the same package.
KANI, Tomoyuki; UCHIDA, Takafumi
The spread of renewable energy is accelerating to reduce greenhouse gas emissions. Power semiconductors used in power conversion systems are thus required to further reduce generated loss and increase current density. To meet these demands, Fuji Electric has developed an All-SiC module with a rated voltage of 2,300V that is suitable for the 2-level circuit of a power conversion system with 1,500V DC. Equipped with the 3rd-generation SiC-MOSFET chips in the HPnC package, which is suitable for high capacities, this module has reduced the generated loss by 50% when integrated in a power conversion system. It has also approximately tripled the current density, despite the module footprint having been reduced by 68%.
KOBAYASHI, Yuto; ZHENG, Mao; ONOGAWA, Atsushi
With the aim of reducing greenhouse gas emissions, the introduction of renewable energy resources is expanding. The increasing installation of solar power generation systems often involves the co-location of storage systems (ESSs) along with solar panels and PCSs. Fuji Electric has offered the lineup of the “M276” Standard 2-Pack IGBT module with 1,200V ratings, which are suited for 3-level PCSs and ESSs used in medium-capacity solar power generation systems. We newly added to the lineup a model with a maximum rated current of 800A. We have expanded the chip mounting area by 35% using two insulating substrates, optimized the chip size, and increased the rated current with the same external dimensions, allowing the module to provide higher output current than the previous one by 38% when used for PCSs and by 17% to 18% when used for ESSs.
ASANO, Taizo; AKAHANE, Masashi; IWAMOTO, Motomitsu
As the transition to the smart factory is increasing using AI and the IoT, predictive maintenance is now required for power electronics equipment to minimize system downtime. One of the causes of failure in power electronics equipment is the lifetime of a power module, and to predict this, it is necessary to accurately detect the temperature of power devices. Accordingly, Fuji Electric has developed a temperature sensor IC to be integrated into power modules. The temperature signal is converted into a digital signal to minimize the effects of switching noise and the circuit is designed to have low temperature dependence and be less affected by noise inside the IC, resulting in the temperature sensing accuracy of ±3°C at the range of -40°C to +200°C.
TAKEDA, Mariko; ITO, Hideaki; KIMIJIMA, Daisuke
The usage of power modules in severe corrosive environments can cause short circuits due to sulfur corrosion. To develop products that can be used even in severe environments, Fuji Electric has established a sulfur corrosion evaluation technology based on corrosion mechanisms. We have studied the effects of voltage application conditions, types of gases, and types of substrates and discovered that applied voltage of alternating current (AC) and using mixed flowing gas (MFG) are suitable for the conditions of accelerated tests for sulfur corrosion. This technology enables us to simulate corrosion morphology in the actual use environment and evaluate the corrosion rate by accelerating 79 times the rate of the test environment based on ISA-71.01 standard.
TANAKA, Ryo; KONDO, Tsurugi; TAKASHIMA, Shinya
Fuji Electric is working on the development of vertical GaN-MOSFETs, which are expected to be the nextgeneration power semiconductor devices following SiC-MOSFETs. We covered the GaN surface with an AlN protective film and perform heat treatment at 1,300°C to activate implanted dopants and remove crystal defects caused by the implantation while suppressing the thermal decomposition of GaN. In addition, combining the plasma CVD process, which allows the MOS interface to be flat, we achieved a vertical GaN-MOSFET with a breakdown voltage of 1,200V. The on-resistance was approximately halved to that of SiC-MOSFETs, demonstrating the feasibility of high breakdown voltage and low on-resistance vertical GaN-MOSFETs.
SAKAI, Takuma; YUKAWA, Fumio; Hiu Baocong
Fuji Electric offers a high-precision IGBT simulator that helps improve the performance and shorten the development periods of power electronics equipment. This simulator outputs the loss and temperature of devices through the selection of circuit configurations and PWM control methods and the inputting of parameters. We newly developed life expectancy calculation function. This function can quickly calculate temperature changes, which are responsible for thermal fatigue of the device, and count the magnitude and the number of occurrences based on the rain flow method. It then applies them to the Arrhenius equation, thereby estimating highly precise power cycling lifetime at actual operating temperatures. This technology has enabled appropriate design with excessive margins reduced.
