Power factor correction of compact fluorescent and tubular LED lamps by boost converter with hysteretic control

Abstract

Compact Fluorescent Lamps (CFLs) and Light-emitting Diode (LED) lamps have received wide acceptance in lighting applications during the last few years. However, without a power factor correction (PFC), the lamps reach a lagging power factor below 0.64 while the total harmonic distortion (THD) in the input current can be over 136%. Therefore, this paper presents an efficient, small size, low cost, and analog technology based on PFC for CFLs and tubular LED lamps. The topology to couple the line with the ballast of the lamp consists of a boost electronic converter under a hysteretic controller that is designed based on hysteretic current mode control. Besides, an experimental prototype is implemented with the PFC applied to a 15 W CFL and 12 W tubular LED lamp. The results show that the prototype corrects the lagging power factor to a value close to 0.98 and that harmonic levels are obtained below the limits set by the IEC 61000-3-2 Class C standard. Furthermore, the test showed that lamps with the PFC can be switched on and off more times than lamps without the PFC due to the low THD produced in the CFL, thus avoiding abrupt changes in the line current. These results are promising, as the controller does not require a compensation ramp as in other PWM control strategies, and it can be adapted to any type of lamp that draws a pulsating input current. In addition, the proposed controller could be applied to correct the power factor or regulate voltage for other applications, as it is an autonomous control technique with compact implementation.