A DC-link-based low-voltage management device with natural language interaction capability

This paper presents a low-voltage management device equipped with an upper-layer natural language instruction parsing module. The device is applied to the low-voltage governance of rural power grids and enables intelligent interaction between natural language commands and devices. The front-end adopts a voltage-multiplying PFC (Power Factor Correction) topology, and achieves power factor correction and stable DC output through voltage-current dual-loop control; the back-end uses a half-bridge inverter circuit combined with LC filtering and quasi-proportional resonant control to output standard 220 V AC voltage. A novel BERT-based natural language instruction parsing model (BERT-NLIP) is proposed to parse natural-language commands and convert them into structured parameter settings for the embedded controller; a synchronous phase-locked technology is adopted to coordinate the phases of the PFC and the inverter, thereby suppressing the double-frequency ripple on the DC bus; a multi-frequency quasi-resonant controller is introduced to specifically suppress odd-order harmonics. A supervisory safety mechanism and a goal-oriented automatic scheduling strategy are further introduced to ensure reliable command execution and support practical line-loss-reduction control. The paper presents the detailed main circuit structure and the design process of control loop parameters. Simulation and experimental results verify that the command parsing accuracy is high, the output voltage is stabilized at 220 V, and the total harmonic distortion rates under empty-load and full-load conditions are as low as 2.5% and 2.1% respectively.