Discrete-Time Trajectory based Control of DC-DC Converters and Applications to LED Driving
- Resource Type
- Conference
- Authors
- Roy, Raktim; Hariharan, K.; Kapat, Santanu
- Source
- 2022 IEEE Applied Power Electronics Conference and Exposition (APEC) Applied Power Electronics Conference and Exposition (APEC), 2022 IEEE. :1190-1195 Mar, 2022
- Subject
- Power, Energy and Industry Applications
Buck converters
Brightness
Switches
Light emitting diodes
Control systems
Steady-state
Trajectory
DC-DC converter
discrete-time trajectory based control
event driven sampling
HB-LED driver
- Language
- ISSN
- 2470-6647
High brightness LED application uses a PWM dimming for controlling the luminous output in which the LED driver is subjected to deliver either No-Load or full load current and the brightness is controlled by the duty-ratio of the dimming PWM. In order to avoid flickering, the dimming frequency ranges up-to tens of kilohertz in automotive applications. However, the controller designed based on a small-signal averaged model cannot satisfactorily perform under such dynamically varying load conditions and also results in reduced efficiency because of high switchings during each transients. This paper presents a geometric switching surface based controller tuning to achieve fast transient recovery without the requirement of linearized model. The digital hysteretic modulator guides the converter trajectory during the transient and steady-state. The event-based sampling approach achieves stable periodic behaviour and steady-state frequency regulation is achieved by adaptively varying the hysteretic band in real-time using time-to-digital (TDC) converter. The synchronous buck converter and high brightness LED array prototypes are made and the proposed control scheme is realized using a FPGA device. The time optimal recovery using both resistive load and LED array are demonstrated using the test results.