近年來，隨著環保意識漸漸抬頭，可再生能源越來越受到各界的重視，其中包含太陽能、風能、水能等等。在輸送再生能源過程中，電流可能為交直流輸送條件，故電網上的直流傳輸及監測更顯重要。最先進傳感器技術可為輸電網即時控制及電能監控提供準確訊息，在許多非電路串接式電流量測傳感器中，基於穿隧磁阻效應之電流感測器，因相較習知霍爾效應電流感測器，具有更高靈敏度、線性度及低功耗等優點，形成現今電流感測器技術發展之重要方向。
本論文針對對稱四氣隙磁芯閉環式TMR電流感測器進行基礎研究，首先基於最小磁場均勻係數之最佳化設計方法，針對磁芯形狀、截面形狀、關鍵尺寸參數及導線固定位置來進行分析，並且增加金屬外殼設計來屏蔽外界干擾磁場，尋求克服偏心誤差之方法，用以達到高精度架構之規格。最後以實驗雛型進行各項論點之驗證，從量測數據分析中，得出本論文之建議架構卻可達成預期之目標，為高精度之電流傳感器提供基礎之研究理論及實驗相關技術。

In recent years, growing environmental awareness has driven increasing attention to renewable energy sources such as solar, wind, and hydro power. In this context, DC transmission within power grids has become more critical. Advanced sensor technologies enable real-time control and monitoring by providing accurate current information. Among non-intrusive current sensors, tunnel magnetoresistance (TMR)-based sensors offer higher sensitivity, improved linearity, and lower power consumption compared to traditional Hall-effect sensors, making them a promising solution in current sensing applications.
This thesis presents a closed-loop TMR current sensor using a symmetric four-air-gap magnetic core. An optimization approach based on minimizing magnetic field uniformity is used to analyze core geometry, cross-section, key dimensions, and wire placement. A metallic shield is also designed to suppress external magnetic interference and reduce eccentricity errors. The sensor design is supported by static and transient magnetic simulations in ANSYS, followed by experimental prototyping and circuit implementation. Final measurements validate the simulation results and confirm the sensor’s high linearity and sensitivity, demonstrating the potential of TMR technology in precision current sensing.