Electrical energy is usually transmitted via the central power grid through alternating current (AC) over high-voltage overhead lines. The growing demand for transport capacity for electrical energy over long distances worldwide poses new challenges for industrial power electronics. In addition, renewable energy sources are increasingly being integrated into the power grid, often delivering electrical energy in direct current (DC). Conventional high-voltage overhead lines can therefore only meet the new requirements to a limited extent.
High-voltage direct current (HVDC) transmission is used to support the AC grid. HVDC has significantly reduced losses in long-distance transmission and is therefore more economical than AC transmission in this area of application. The focus at Fraunhofer IISB is on the standardization of components in modular multilevel converters (MMC). These semiconductor-based MMC stations are the most important components at the end points of high-voltage DC transmission. Here, conventional AC transmission incurs transfer losses, which are avoided by MMC solutions. This is made possible by using cascaded semiconductors in the highest current power ranges so that DC current can be generated and regulated flexibly.
With our industry partners, we develop all components of the MMC submodules, including driver switches, safety concepts, key components, and valve-tower design for the MMC stations. In addition, individual failure protection mechanisms are evaluated, tested and assessed.
Cooperating with us, you can expect:
- High availability and reliability at component and system level
- State-of-the-art functional approaches, especially with regard to operational safety
- Many years of experience gained through projects with several international cooperation partners