Long-distance power transmission in wide-area highway DC microgrids leads to terminal voltage drops, which severely degrades power quality. Conventional schemes predominantly adopt full power converters (FPC), which suffer from limited power density and low system efficiency. To address this issue, this paper proposes a high-efficiency DC series compensator based on Partial Power Processing (PPP) architecture and an improved Model Predictive Control (MPC) scheme. Firstly, the topological structure of the proposed compensator is introduced, and its operating principle is analyzed. Then, the application of the MPC strategy within this equipment is explored, followed by an analysis of its parameter sensitivity. Furthermore, a noise suppression factor is incorporated to significantly mitigate the impact of sampling noise on the MPC, thereby enhancing control robustness. Additionally, a current-sensorless MPC is formulated to reduce hardware complexity and lower potential failure rates. Finally, a 200W experimental prototype is developed. Experimental results demonstrate that the proposed topology and control strategy can achieve precise voltage compensation with superior dynamic and steady-state performance.