A Partial Power Regulated DC Transformer Optimized by Genetic Algorithm for High Step-Up Power Conversion

An isolated partial power regulated DC transformer for step-up applications is proposed in this paper. The proposed converter consists of two DCXs operating at the unregulated state and a non-isolated DC-DC converter for the system output voltage regulation. The primary sides of the two DCXs are integrated by sharing a common bridge arm and the merging of the secondary side components can be realized by the series connection of the secondary windings, which is beneficial to reduce the number and cost of components. The partial power processing is realized with different input voltages of the two bridge arms of DCX1 and the power handled by the voltage regulator can be reduced furtherly by the two transformers. In order to minimize the total power loss furtherly, the genetic algorithm is adopted to realize parameter optimization. Compared with the traditional two-stage structure, the voltage regulator only processes a small part of the power, resulting in lower devices stress and power losses. The steady-state working principle, voltage regulation scheme, power share criterion and parameters optimal design are introduced in detail. An experimental prototype with 24-30V input and 200V/ 1A output is built under 1MHz switching frequency. The achieved peak efficiency is 95.45%.