基于逆变技术的正弦交变磁场治疗系统的研究

Research on sinusoidal alternating magnetic field therapy system based on inverter technology

目的:研究并设计一款频率和磁场强度均连续可调的正弦交变磁场治疗系统,以克服市场上交变磁场治疗系统输出频率单一且输出磁场强度有效值低等缺点。方法:以多绕组亥姆霍兹线圈为磁场发生器,在逆变技术的基础上,运用考虑死区的双极性等效面积法和变速积分增量式PID(proportion,integration,differentiation)控制算法实现线圈中磁场频率和强度的精确控制;并通过仿真计算和系统电流及磁场强度测试,验证产生的波形的准确性和磁场强度的精确度。结果:该磁场治疗系统性能较好,正弦波的总谐波失真度(total harmonic distortion,THD)满足国际标准的规定,且得到的磁场强度符合理论计算和磁场仿真预期。结论:该磁场治疗系统能够产生连续可调的磁场,对于保证医护人员开展相关研究具有积极作用,为磁疗系统的研究提供了重要的技术参考。

Objective To develop a sinusoidal alternating magnetic field therapy system in order to overcome the disadvantages of the single output frequency and the low effective value of the output magnetic field strength of the alternating magnetic field therapy system in the market,of which the frequency and magnetic density both were continuously adjustable.Methods Multi winding Helmholtz coil was used as the magnetic field generator.On the basis of inverter technology,bipolar equivalent area method considering dead zone and variable speed integral incremental PID control algorithm were used to achieve the accuracy control of magnetic frequency and density in the coil.The accuracy of the resulting waveform and the accuracy of the magnetic field strength was verified by simulation calculation and system current and magnetic field strength test.Results The magnetic field treatment system gained high performance,total harmonic distortion(THD)of sine wave met the requirements of international standards.The obtained magnetic density was as expected of the simulation and calculation.Conclusion The device provides continuously adjustable magnetic field,which has a positive effect on the research for the medical staff,and technical references are provided to the research of magnetic field therapy system.