Development of an FPGA-based Adaptable Peak Current-Mode Control for Use in Green Energy Conversion

An adaptable peak current-mode control (APCMC) was developed for a buck converter. This APCMC was implemented using a field programmable gate array (FPGA) and has applications in green energy conversion. An FPGA was chosen to implement the APCMC as it has the inherent capability for multitasking and has the capability for adding functionality without changing the hardware. The number of parts was minimized for the APCMC as it only requires an FPGA, power and timing circuitry, a comparator, and a single-pole RC filter. Instead of using a compensating ramp with a constant slope as is used in conventional peak current-mode control, the APCMC uses a compensating curve that has a varying slope that is optimized for each value of the duty cycle. The compensating curve was chosen such that it will not only prevent sub harmonic oscillations, but it will also enable a deadbeat response at all values of the duty cycle. The compensating curve was derived from a control model that used modified z-transforms.