POWER SUPPLY CIRCUIT FOR DRIVING SURFACE DISCHARGE ELEMENT

PROBLEM TO BE SOLVED: To provide a power supply circuit for driving a surface discharge element that can perform a stable operation without limiting the output range even when the floating capacitance of the surface discharge element varies due to an external environment or discharge.SOLUTION: In a power supply circuit for driving a surface discharge element in which a discharge electrode and an induction electrode are arranged through a dielectric body interposed therebetween, a switching circuit is configured by connecting two sets of series circuits each comprising positive-side and negative-side switching elements in parallel, and supplied with DC power. A smoothing capacitor is connected to the switching circuit in parallel, and the primary side of a transformer is connected between the output terminals of the switching circuit. Current detection means detects current flowing through the negative-side switching element, and control means turns off the negative-side switching element based on a zero-cross point of the current detected through the current detection means.SELECTED DRAWING: Figure 1 【課題】外部環境や、放電によって沿面放電素子の浮遊容量が変動しても、出力範囲を制限することなく安定動作可能な沿面放電素子駆動用電源回路を提供する。【解決手段】実施形態の沿面放電素子駆動用電源回路によれば、放電電極と誘導電極とがそれらの間に誘電体を介して配置される沿面放電素子を駆動するものにおいて、スイッチング回路は、正側及び負側スイッチング素子からなる直列回路を２組並列に接続してなり、直流電源が供給される。平滑コンデンサはスイッチング回路に並列接続され、スイッチング回路の出力端子間に変圧器の１次側が接続される。電流検出手段は、負側スイッチング素子に流れる電流を検出し、制御手段は、電流検出手段を介して検出される電流のゼロクロス点に基づいて、負側スイッチング素子をターンオフさせる。【選択図】図１