Analysis and Comparison of DBD Power Supplies With Different Control Methods

For the topology of a full-bridge circuit connected to a small-leakage transformer, both symmetrical and phase-shifted control can generate bipolar high-voltage pulses. However, which one of these two control methods is better or worse has not yet been discovered. In this article, we investigate their difference in depth through theoretical analysis as well as experimental verification to explore the effects of input voltage, frequency, and pulsewidth on the output characteristics of each control method. It is found that at the end of the pulse under phase shift control, the primary side of the transformer is shorted, which results in a steep falling edge, causing a secondary discharge, and the excimer lamp is driven with higher luminous efficiency. Meanwhile, the energy stored in the parasitic components and load capacitance is completely released so that the initial voltage before the start of each pulse is zero. Thus, the peak pulse voltage is not affected by the frequency and pulsewidth but changes with the input voltage. At the end of the pulse under symmetrical control, the primary side of the transformer is open-circuited, and the remaining energy can only be released slowly through the excitation resistor, which does not allow for a steep falling edge. Thus, the discharge efficiency will be lower. At the same time, the initial voltage is not zero before the start of each pulse, resulting in the peak output voltage being affected by the input voltage, frequency, and pulsewidth simultaneously.