Development Of A Modular High-Repetition-Rate Nanosecond Pulse Generator Based On Blumlein And TLT

In recent years,the number of cancer patients in China remains high.Cancer brings great physical and psychological trauma to the patients.To combine the advantages of both microsecond pulsed electric field(?sPEF)and nanosecond pulsed electric field(nsPEF)treatments,a high-frequency nsPEF treatment of tumor is introduced recently.The method is expected to solve the problem of surface discharging in the course of nsPEF treatment and muscle contraction during the treatment of ?sPEF.This method has received extensive attention.High-frequency nanosecond pulse generator is the main equipment to study the effect of tumor cells exposed to high-frequency nsPEF.Therefore,the development of a high-frequency,fast-rising-edge and narrow-pulse-width nanosecond pulse generator is important.Firstly,the principles of basic topological structures involved in the pulse generator were described,including the principle of Blumlein and transmission line transformer(TLT).The principles of traditional Blumlein and improved Blumlein were introduced.The wave processes of Blumlein in charging and discharging conditions were analyzed.The timing of control signals and ideal output waveforms were analyzed.The principles of traditional and improved TLTs were illustrated.The connection mode of the output side of the TLT was presented.Three different-type generator topologies combining improved Blumlein and TLT were proposed in the paper,including unipolar,bipolar and polarityadjustable topology.The control sequence of three topologies was introduced.Simulation circuits was established with PSpice,the ideal output and the influence of stray parameters for the output were simulated and analyzed.Secondly,the designation of all parts in the generator was described.The transmission lines in the generator were designed with both microstrip lines and coaxial cables.So,two type Blumleins and TLTs were obtained.Different type generators were achieved by combining different type Blumlein and TLT.Solid-state switch was chosen as power switch in the generator.The drive circuit was designed and achieved by PCB.FPGA was used to control the system.The control program and the transmission path of control signals were devised.Finally,a test platform was established for testing the performance of the generators.Three generators were fabricated according to different types of Blumlein and TLT.The performance of these generators was tested in different conditions.The final two-stage unipolar generator can output pulses with amplitude of 0-2kV,pulse width of 20 ns,and a repetition rate of 0-10 kHz.The three-stage bipolar generator can output bipolar pulses with amplitude of 0-3kV,pulse width of 120 ns,and a repetition frequency of 0-10 kHz.The four-stage generator with adjustable polarity can output pulses with amplitude of 0-10 kV,a pulse width of 30 ns,repetition rate up to 200 kHz and adjustable polarities.All these generators had good performance and can be extended to get higher output parameters.These generators can be used for the research of tumor treatment as hardware platforms.