Pulse Modulation Technology Of Repetitive Frequency Pulse Power Source Based On Solid State Switch And Its Application

With the continuous development of semiconductor technology, semiconductor switches is replacing gas switches in pulse generators due to their many advantages such as compactness, high PRF, good controllability, long lifetime, and excellent stability.For this reason, employment of solid-state switchesinpulse modulators began to prevail in past two decades. High power pulses have found use in many fields such as industrial manufacturing, environmental protection and medical treatment, etc. These applications require high-voltage, high PRF, short risetime, more compact and high-efficiency pulse generators. To meet these requirements, this thesis presents how to design all solid-state pulse generators with semiconductor switches and magnetic switches (MSs). Four major parts are included.Firstly, the implementation methods of all solid-state pulse voltage multipliers are studied basing on semiconductor switches, and both unipolar and bipolar rectangular high-voltage pulses are obtained. We creatively introduced the truncation technology and phase-shift control method into the all solid-state pulse voltage multipliers and well-shaped rectangular pulses are obtained on the resistor loads. One unipolar all solid-state Marx generator with-32kV output voltage, one unipolar all solid-state pulse adder with20kV/200A output voltage and one bipolar all solid-state pulse adder with±5kV/60ns output volage were constructed. Their performances were introduced respectively.Secondly, the design and resetting process of magnetic switches are studied. The influences on the magnetic switch performance of many magnetic parameters are analyzed, specially the influence on permeability and magnetic loss of dB/dt. Methods of increasing the initial permeability and aspect ratio through improving the manufacturing process are summarized. The idea of measuring the dynamic magnetic parameters based on the actual circuit is proposed. Dynamic hysteresis curves of different magnetic cores are obtained, which provide accurate data for the design of magnetic switches. Different resetting methods of magnetic cores are discussed and a new self-resetting circuit with magnetic switches is proposed for the first time.Thirdly, different topologies are discussed basing on all solid-state pulse voltage multipliers and magnetic pulse compression (MPC) technology. The design of the magnetic switch for the typical one-stage magnetic pulse compression circuit is introduced in details and the influences on the compression effect of each parameter are analyzed. With the measured dynamic magnetic parameters, PSPICE simulation was carried out and the results matched well with the experimental results. In the typical one-stage MPC circuit, the pulse risetime was compressed from560ns to30ns. Pulses with30kV and30ns risetime were obtained, based on this typical one-stage MPC circuit. When MSs are connected in series with all solid-state pulse generators, the magnetic assistant effect will decrease the switching loss and shorten the pulse risetime. The one-stage MPC circuit with a pulse forming line output rectangular pulses with12.4kV voltage amplitude,44ns risetime and falltime,220ns pulsewidth. It should be emphasized multy discharges on the dielectric barrier discharge (DBD) load under a single shot are excited when Blumlein transmission lines (BTLs) are discharged by a MS. Thus extremely intense non-thermal plasma is generated, which has great potential in industrial applications.Fourthly, preliminary DBD experiments are carried out with a nanosecond pulse generator based on BTLs and MSs. The excited plasma is used to dispose Rhodamine B in the solution and the disposal effect is very good. The influences on the disposal effect of different electrical parameters are analyzed.