Offshore wind farms are turning to direct‑current (DC) collection systems because they cut cable losses, need fewer conversion steps and are easier to control. The heart of these systems is a high‑power DC‑DC converter that lifts the low‑voltage DC from each turbine up to a medium‑voltage level for efficient transmission. Traditional converters struggle when power climbs into the hundreds of kilowatts, hitting efficiency and reliability roadblocks. A research team at the Chinese Academy of Sciences’ Institute of Electrical Engineering has now cracked this problem. By building a detailed loss‑analysis model for a three‑level LLC resonant converter, they pinpointed where energy was being wasted—in semiconductor modules, high‑frequency transformers and rectifier circuits. Their solution, called a “loss reconstruction strategy,” dynamically tweaks control variables using a hybrid of variable‑frequency and pulse‑width modulation. This keeps the biggest loss sources suppressed across the whole power range. Prototype tests showed the new converter reaches a peak efficiency of 98.1% and maintains above 97.8% efficiency over a range that’s 30% wider than conventional designs. The result is a smaller, lighter converter that simplifies offshore wind power collection, boosts safety and reliability, and can be adapted for solar farms, large‑scale storage and data‑center transformers. The work, published in the IEEE Journal of Power Electronics, is backed by China’s “Green Power Future” R&D program.
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