Microcontroller Based High Power Factor Electronic Ballast to Supply Metal Halide Lamps
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 59, NO. 4, APRIL 2012
1779
Microcontroller-Based High-Power-Factor Electronic Ballast to Supply Metal Halide Lamps
Marco Antonio Dalla Costa, Member, IEEE, José Marcos Alonso Álvarez, Senior Member, IEEE, Jorge García, Member, IEEE, André Luís Kirsten, Associate Member, IEEE, and David Gacio Vaquero, Student Member, IEEE
Abstract—The analysis, design, and implementation of a microcontroller-based electronic ballast to supply metal halide (MH) lamps are presented. The proposed topology is based on the integration of the buck and flyback converters, the former providing power factor correction and the latter controlling lamp power. The lamp is supplied by a low-frequency square-waveform current, which is a convenient way to avoid acoustic resonances in high-intensity discharge lamps. Both converters operate in discontinuous conduction mode, thus allowing the use of only one highfrequency switch and simplifying the control. The electronic ballast is digitally controlled by using a low-cost microcontroller PIC16F684. The microcontroller performs all the necessary tasks during starting, warming-up, and steady state, including closed-loop control of lamp current and protections. The closed-loop control takes into account the lamp dynamical impedance. Experimental results for a 35-W MH lamp are presented, and the obtained overall efficiency is 90%. Index Terms—Electronic ballasts, metal halide (MH) lamps, microcontrollers.
I. I NTRODUCTION LECTRONIC ballasts for high-intensity discharge (HID) lamps have attracted attention, compared to electromagnetic ballasts, because of their advantages: lighter weight, smaller size, higher efficiency, higher immunity to supply voltage changes, optimized performance, digital control and supervision, etc. The main drawback of using electronic ballasts to supply HID lamps is the risk of the acoustic resonances (ARs) rising [1]. AR is the generation of standing pressure waves in
1779
Microcontroller-Based High-Power-Factor Electronic Ballast to Supply Metal Halide Lamps
Marco Antonio Dalla Costa, Member, IEEE, José Marcos Alonso Álvarez, Senior Member, IEEE, Jorge García, Member, IEEE, André Luís Kirsten, Associate Member, IEEE, and David Gacio Vaquero, Student Member, IEEE
Abstract—The analysis, design, and implementation of a microcontroller-based electronic ballast to supply metal halide (MH) lamps are presented. The proposed topology is based on the integration of the buck and flyback converters, the former providing power factor correction and the latter controlling lamp power. The lamp is supplied by a low-frequency square-waveform current, which is a convenient way to avoid acoustic resonances in high-intensity discharge lamps. Both converters operate in discontinuous conduction mode, thus allowing the use of only one highfrequency switch and simplifying the control. The electronic ballast is digitally controlled by using a low-cost microcontroller PIC16F684. The microcontroller performs all the necessary tasks during starting, warming-up, and steady state, including closed-loop control of lamp current and protections. The closed-loop control takes into account the lamp dynamical impedance. Experimental results for a 35-W MH lamp are presented, and the obtained overall efficiency is 90%. Index Terms—Electronic ballasts, metal halide (MH) lamps, microcontrollers.
I. I NTRODUCTION LECTRONIC ballasts for high-intensity discharge (HID) lamps have attracted attention, compared to electromagnetic ballasts, because of their advantages: lighter weight, smaller size, higher efficiency, higher immunity to supply voltage changes, optimized performance, digital control and supervision, etc. The main drawback of using electronic ballasts to supply HID lamps is the risk of the acoustic resonances (ARs) rising [1]. AR is the generation of standing pressure waves in