News: Microelectronics
23 November 2020
Infineon’s CoolSiC used in Fronius’ solar inverter
Fronius International GmbH of Wels, Austria has launched the Symo GEN24 Plus solar inverter, whose Multiflow technology makes it suitable for a wide range of applications supporting energy self-sufficiency. As well as providing power for direct use in the household it also has an interface for energy storage systems. In addition, the hybrid inverter is designed for water heating and the charging of electric cars, and can be connected to external systems.
The new solar inverter uses silicon carbide (SiC) CoolSiC MOSFETs from Infineon Technologies AG of Munich, Germany with an efficiency of over 98%. In combination with the high-voltage storage system from BYD, the Symo GEN24 Plus has achieved a record value in the System Performance Index (SPI) of 94% in the 10kW class, it is claimed, becoming the only one in this combination to achieve Class A energy efficiency.
Picture: Fronius’ Symo GEN24 Plus solar inverter combines CoolSiC MOSFET modules in the booster and battery input with hybrid modules in the inverter stage.
“SiC modules can be used to build very energy-efficient, robust, and reliable inverters. This technology enables a significant increase in switching frequency,” says Andreas Luger, head of R&D Power Electronics in the Solar Energy business unit of Fronius. “Compared to the previous generation, the functionality is significantly improved, while its size remains comparable. Each device now also has an output for a secure power supply, and backup power, in addition to the standard connection options for a hybrid inverter,” he adds.
“To maximize the advantages of SiC, engineers from Fronius and Infineon have jointly optimized the layout and chip assembly of the modules,” says Peter Wawer, president of Infineon’s Industrial Power Control Division. “Ultimately, the close communication between the development teams enabled system advantages that correspond to customer needs. Based on our tried and tested Easy module, the inverter's booster stages now use 1200V CoolSiC MOSFETs in combination with CoolSiC diodes. This full-SiC solution thus ensures maximum efficiency.”
Full-SiC is also used for the battery stage. One Easy 1B 1200V with an on-resistance (RDS(on)) of 45mΩ is used in the bidirectional DC/DC converter. The inverter stage implements a SiC hybrid solution in an Easy 2B module, which has also been tailored to the needs of Fronius. The NPC1 topology combines silicon-based 650V TRENCHSTOP 5 insulated-gate bipolar transistors (IGBTs) and rapid diodes with CoolSiC Schottky diodes. The modules are controlled in all stages with an EiceDriver IC gate driver.
The combination of SiC MOSFET modules in the booster and battery input with hybrid modules in the inverter stage ensures the best possible ratio of efficiency and cost, it is reckoned. As Infineon’s SiC power semiconductors have a high power density, the Fronius Symo GEN24 Plus offers many functions such as backup power, storage connection, multi-MPP tracker and energy management. The inverter weighs only 24kg and has a small volume (594mm x 527mm x 180mm). Its active air-cooling can reduce the temperature of the power electronics parts, and thus extend service life.
The inverter is available in the power classes 6, 8 and 10kW. Fronius supplies this inverter primarily in Europe, South America and Australia.
