四级传输线脉冲变压器研制

Development of 4-stage transmission line pulse transformer

介绍了一种传输线脉冲变压器(TLT)的最优化设计理论,在此基础上,研制了一台四级传输线脉冲变压器。所研制的TLT所使用的磁芯基本符合级间无耦合结构TLT最优化设计的要求。采用了柔韧性好的同轴电缆,绕制完成后各级次级线电感值大小分别为1.83,3.52和5.41 mH,符合预定目标。利用Blum-lein作为脉冲源,对所研制的TLT进行了测试,测试结果表明:输入脉冲宽度150 ns,幅值10 kV,上升前沿20ns,输出脉冲宽度150 ns,幅值约40 kV,上升前沿约20 ns,基本波形保持较好,但下降沿和尾部波形不理想,初步分析可能的原因是TLT输出端杂散电容电感引起的阻抗不匹配。此变压器可用于低阻抗陶瓷脉冲形成线输出端的阻抗变换。

The optimization theory of a transmission line pulse transformer（TLT） has been introduced, and a 4-stage TLT was built and tested based on the theory. Magnetic cores used in this TLT met the optimization requirement of the TLT structure without coupling between stages. Coaxial cables with good flexibility were used, and the secondary line inductance of each stage was 1.83, 3.52 and 5.41 mH respectively, which was up to the preset goal. Through a Blumlein pulsed generator, a pulse with a voltage up to 10 kV, a duration of 150 ns and a rise-time about 20 ns was injected into the TLT. Then at the output terminal of the TLT, a pulse with an amplitude of 40 kV, a duration of 150 ns and a rise-time slightly larger than 20 ns was obtained. The result indicates that the pulse＇s basic shape can be maintained well through this TLT except the falling edge and tail. The probable reason, imperfect load match brought by stray inductance and capacitance, is preliminarily analyzed. This transformer can be used to realize the output impedance transformation of the ceramic pulse forming line with low characteristic impedance.