Valve Base Controller (VBC) Used in HVDC Flexible System

Valve base controller (VBC) is the core part of control system for Modular Multilevel Converter (MMC) of HVDC Flexible, comprising man-machine interface, current control unit, bridge-arm control unit, valve monitoring unit, etc. Multiple communication methods such as CAN bus, high speed fiber optic are introduced in the system to realize massive data transfer as well as high speed valve monitoring and control. By means of a dual redundant hot standby structure and efficient and robust control arithmetic, including in self-drive synchronous inhibition algorithm and dynamically optimizing multi-target voltage distribution algorithm, VBC can ensure the HVDC Flexible system runs in a sound and stable manner. At the same time, valve monitoring unit carries out real-time check on a number of parameters and devices like voltage, current, valve status, circuit breaker, water-cooling system and the system itself, abnormality of any kind is followed up rapidly by corresponding protection action, thus guaranteeing the security of the primary side. VBC has been proved reliable and effective in VSC-based NanHui wind farm integration project.