메탈헬라이드램프용 순시재점등 전자식안정기 개발

The most shortcoming of metalhalide lamps is what the instant restarting cannot be realized when the arc tube is in the hot condition. The discharge starting voltage of arc tube in the hot condition is much higher than in the cold condition. Therefore it takes about five minutes to restart the metalhalide lamps, that is to say, it is possible to start when the pressure and the temperature are decreased. But, if the lamp is restarted in the hot condition, we must supply the high voltage pulse with 20kV at the both sides of lamps. The proposed electronic ballast is consist of a electromagnetic interference (EMI) filter, a power factor correction (PFC) circuit, a flyback converter, a half-bridge inverter, and a high voltage ignitor circuit. By this composition we can restart the lamp with the voltage 20kV, even if the lamp is in the hot condition.