为限制Nd:YAG激光器闪光灯抽运源在触发预燃时的功耗和电磁干扰,以符合国家关于医用电气设备对电磁兼容性的要求,研发了准谐振腔体触发预燃技术。由于脉冲变压器的寄生参量无法消除,会在电路中产生复杂的振荡过程。利用这一谐振特性,通过调节触发频率,使之与谐振频率相同,达到准谐振状态点燃闪光灯。实验证明该电路稳定可靠,其峰值电压可降到10kV以下,远低于同类闪光灯触发电压16kV的标称值。结果表明,该电路完全达到了国家关于医用电气设备对电磁兼容性的标准。

In order to restrict the power dissipation and electromagnetic interference when the flash-lamp-pumped system of solid laser is at the time of burst and preignition,the technology of quasi-resonant triggering and preignition was developed.Based on this technology,a long-pulsed medical Nd:YAG laser was designed to meet the electromagnetic compatibility requirements of national medical electrical equipment.Because parasitic parameters of the pulse transformer can not be eliminated,complicated oscillation should occur in the circuit.Making use of this resonance characteristic of the pulse transformer,the triggering frequency was adjusted the same as the resonant frequency,namely,quasi-resonant state,to ignite flash-lamp.The experiments proved this circuit was reliable and stable.The value of triggering-pulsed peak voltage could descend below 10kV,much lower than the nominal triggering voltage,16kV.The results show that the circuit completely meets the national electromagnetic compatibility standards on medical electrical equipment.