Design And Research Of Pulse Generator With RSD

High power and super-high speed semiconductor switch RSD(Reversly Switched Dynistor) has great advantages in pulse power system : simultaneous turn-on in all area, high di/dt, high speed, high power, low power loss, infinite series, easily used in series and parallel connection, low cost and long lifetime etc. It is one of perfect switches of pulse power system.Based on the structure and turn-on mechanism of RSD, the turn-on characteristics and condition is researched, which has provided basis for the application of RSD in pulse power system. The normal turn-on needs two conditions: (1) In pre-charge stage, the voltage polarity of RSD is reversed. At this time, the magnetic switch must separate the main circuit and the pre-charge circuit. (2) Avoid partial turn-on, sufficient charge must be injected in pre-charge stage. The injected plasma must be distributed along whole J2 junction.One of the key devices in RSD's trigger is magnetic switch. It is employed as a separator between the main circuit and the pre-charge circuit. Based on the basic theory of electromagnetism, the relationships between the winding turns, the cross-section of the magnetic core, separating voltage and saturation time are discussed. The experiments have been done. The results have testified the truth. The reset circuit of magnetic switched is also discussed. In order to decrease the influence to the main circuit, a method of decrease the saturation inductance is introduced.Another problem in pulse generator with RSD is how to trigger RSD's turn-on. The difficulty is the high voltage of the trigger circuit because the trigger circuit is parallel with the main circuit. In this paper, there shows two solutions. One is used thyristors in series, another is used pulse transformer. The thyristors solution is suitable for medium or low voltage lever, and the pulse transformer is for high voltage lever. When uses thyristors in series, there are two issues. One is voltage balancing in static state, which can be solved by balance resistance. The other issue is how to solve the voltage imbalance because of the asynchronous turn-on. This can be solved by RC absorb net. The transformer solution, especially using small size RSD to trigger large size RSD, is also discussed. In this solution, the key factors are the transformer's saturate time, the pre-charge current of small size RSD, the magnetic switch's saturate time, the pre-charge current and time of large size RSD. To simple the design of the pulse transformer, an equal circuit of pulse transformer is proposed.As a part of pulse power system, the measurement of pulse current is urgency to be solved. The Rogowski coil in measurement pulse current has many advantages: linearity, high response ability, insulated with the measurement circuit and low cost. But because of the resistance of the coil, the measure wave is aberrant. In this paper, the Rogowski coil is researched, and a revise method is discussed to solve the aberration, which let the Rogowski coil be suitable for the pulse system.