Electronic ballast with constant power output controller for 250W MHD lamp

摘要

In this paper, the electronic ballast was developed to control 250W metal halide lamp. To avoid acoustic resonance phenomenon, we calculated the acoustic resonance band and determined the driving frequency to from 70kHz to 100kHz. Due to the switching loss of MOSFET, many problems are caused in the inverter circuit during lighting the lamp, so we have reduced the loss by connecting the capacitor to reduce inrush current. In this paper, main research area is to find the methods to operate the lamp on regulated constant output. After detecting the current I and voltage V of the lamp, we changed the driving frequency by changing the DC voltage level.