Practical Evaluation of Dimming Control Methods for Electronic Ballasts

The authors compare and evaluate 1) the traditional frequency-control dimming method and 2) a recently-patented voltage-control dimming method in electronic ballasts for fluorescent lamps. The power factor, energy efficiency, electronic loss, efficacy (lumen/W), and crest factor of 2times36W electronic ballasts based on these two dimming methods are recorded and compared over a wide dimming range. It is found that the voltage dimming control approach is much better than the frequency control method in most of the compared aspects as the lamp is dimmed. In particular, voltage dimming approach has much higher energy efficiency and lumen per watt than the frequency control one. Unlike the frequency dimming method, voltage dimming control has a distinctive feature in that its electronic loss decreases with decreasing lamp power