Linear Active Disturbance Rejection Control of Buck-boost PFC based LED Driver Circuit

Light Emitting Diode (LED) technology has emerged as a better alternative to conventional lighting options like incandescent lamps, CFLs, etc. It has various advantages over conventional alternatives, e.g., better efficiency, longer life, multi-colored light, fast dimming capabilities, etc. LED driver circuits are adapted to supply power to LED loads. When LEDs are supplied through the AC mains, they are required to operate at a power factor near unity, creating a need for power factor correction (PFC) in the driver circuit. Also, the driver circuit should maintain a constant voltage at the load terminal such that a flicker-free operation of the LED is obtained. Buck-boost PFC configuration, derived from the basic buck-boost converter when operated in the discontinuous current conduction mode has inherent power factor correction property. This simplifies the control of the configuration to only a single voltage control loop. Active Disturbance Rejection Control (ADRC) is based on the control law implemented with the help of estimated states which are estimated with the help of an Extended State Observer (ESO). This work is focused on extending the concept of linear ADRC (LADRC) to buck-boost PFC based LED driver circuit and to evaluate its performance.