The design of a low-power gradient coil is of great importance for reducing the volume of low-field nuclear magnetic resonance (NMR) and improving its detection capability. In this paper, a gradient coil of low power without extra cooling device is optimized by solving the harmonic distribution of magnetic field at the field point and introducing the power consumption as the optimization objective function. Then, the gradient coil is designed by finite element method to solve the gradient field distribution in reverse. The simulation results show that the designed gradient coil possesses a very high linearity. Finally, the designed gradient coil is measured by Hall probe and NMR. The experimental results show that the designed gradient coils have the characteristics of strong gradient field, high linearity and low power. In conclusion, the gradient coils designed based on magnetic field harmonic analysis method are provided with low power consumption and excellent performance.

低功率梯度线圈的设计对于减小低场核磁共振（NMR）的体积和提高其检测能力具有重要意义。本文通过求解场点磁场谐波分布，引入功耗作为优化目标函数，对无额外冷却装置的低功率梯度线圈进行优化。然后，利用有限元法设计梯度线圈，逆向求解梯度场分布。仿真结果表明，所设计的梯度线圈具有很高的线性度。最后用霍尔探头和核磁共振对设计的梯度线圈进行测量。实验结果表明，所设计的梯度线圈具有梯度场强、线性度高、功率小等特点。综上所述，