Digital Control of Four Switch Synchronous Buck-Boost Power Converter based on PIC18F4520 Microcontroller

The paper presents a practical realization of digital voltage control of a synchronous "buck-boost" power converter, with a wide range of input voltage changes. The power converter is adapted to the power from input solar panels and for different types of output loads. The paper analyzes the basic principles of above mentioned power converter in continuous conduction mode. Also, the paper presents a control strategy based on the PIC18F4520-MICROCHIP microcontroller. All measuring signals (input and output voltage, as well as output current) are connected to the input of the digital controller via galvanically isolated measuring circuits, with appropriate A/D conversion. Finally, some of the most important experimental results obtained during testing of the synchronous “buck-boost" power converter at different input voltages and different output loads are presented.