The Push-Pull Plasma Power Supply - A Combining Technique for Increased Stability

Abstract

During the operation with a double-electrode Non-thermal Plasma (NTP) reactor with a Gliding Arc Discharge (GAD) there are many technical difficulties [1]. The reactor is the resistance energy receiver with a strongly non-linear characteristics. What is more, high voltages above 10 kV are needed for pre-ionisation during the ignition process, while after ignition, the maintaining voltage is several times less. There is also a need to limit the current immediately for keeping non-thermal conditions in the reactor. A plasma reactor used here is briefly described in the Polish patent [2]. In order to meet the requirements of the reactor's supply, there is a strong suggestion to use a Switched- Mode Power Supply (SMPS), the construction of which combines many interesting features that are not commonly encountered. The push-pull topology is not commonly used in such applications. As a standard, it is used in inverters where the low input voltage is processed. The topology requires a primary winding with special symmetry and the alternating current on the secondary side is obtained by switching the primary current between the two halves of the primary coil by delivering current to the centre tap of the primary coil. In this case, the primary current is switched by IGBT transistors. The control can take place both from the microcontroller and the integrated analogue controller, whose advantage is resistance to radiated disturbances. The power supply can successfully achieve power above 1 kW; however, when working with Micro Gliding Arc Plasma Reactor (MGAPR), such power ranges are not required [3]. In addition, the project is seen to have broad scientific perspectives of development. Improvements of ignition properties were obtained using achievements resulting from work on switching overvoltages. The power supply has a power and frequency regulation. Both of them can work in control feedback loops, but here in the experiment they are not used. The features mentioned are exceptional for the power supply and provide a wide range of possibilities in supplying the nonthermal plasma reactors. There are very wide adjustment properties in the range of 13–26 kHz and it has been proven to be exceptionally efficient in fulfilling its purposes.