A Wi-Fi-Based Wireless Firmware Download System for Modular Multilevel Converters

A modular multilevel converter (MMC) consists of a large number of submodules, each containing an embedded controller whose firmware needs to be updated as needed. Conventional wired programming methods, such as JTAG-based individual programming, become increasingly inefficient as the number of submodules grows, resulting in increased maintenance time and wiring complexity. In large-scale MMC systems, individually connecting each submodule controller via wired interfaces not only prolongs the update procedure but also increases the risk of human error during maintenance. This paper proposes a Wi-Fi-based wireless firmware download system for MMC submodule controllers based on a dual-core DSP(Digital Signal Processor). The proposed system adopts a hierarchical communication structure consisting of a host PC, a fixed wireless access point (AP) installed inside the converter panel, Wi-Fi modules, and DSP controllers. Firmware images are transmitted wirelessly via TCP/IP, and a group-based sequential download method is applied to distribute network load and ensure communication stability under large-scale deployment. A custom bootloader and flash kernel are implemented on the DSP to perform reliable flash erasing, programming, and verification with checksum-based integrity checking at each stage. The system supports independent firmware download for dual-core CPU1 and CPU2, and provides real-time status monitoring including connection state, firmware version, and download progress through a graphical HMI(Human-Machine Interface). Experimental results confirm that the proposed system enables reliable and efficient wireless firmware updates, significantly reducing maintenance procedures compared to conventional wired methods.