The project undertaken was to design and build a direct current (dc) to dc boost converter. More specifically, a zero-voltage-transition step-up dc-dc converter. With variable input voltages ranging from 6V dc to 12V dc using the pulse width modulation module of the PIC microcontroller, this converter has potential uses with fuel cell, solar panel applications and any DC appliance requiring voltage far more than the source can deliver.
This converter is designed to provide stable 12V output by stepping up the available low voltage supply without any storage element. The output voltage is controlled by microcontroller unit using voltage feedback technique. The output of the boost converter is measured continuously and the value is sent to the microcontroller unit to produce pulse width modulation signal. The PIC controller produces PWM signal using inbuilt CCP (compare, capture and PWM) module. The PWM signal which controls the switching of MOSFET. Thus by switching of MOSFET it would try to keep output as constant. Simulation and experimental results describe the performance of the proposed design built around a PIC16Fxxx series Microcontroller.
For the design solution, the implementation of a microcontroller based boost converter with feedback contains 3 subsystems – a conventional PWM boost converter, a snubber cell, and a control circuit. A PIC microcontroller is used to send the gating signals to a driver which drives the Metal-Oxide-Semiconductor Field Effect Transistors (MOSFET), allowing the converter’s output to be kept steady at 12V and 250Watt through pulse width modulation, even with a fluctuating input voltage.
A switching frequency of 100 kHz frequency was achieved, and the method of soft switching implemented was zero voltage transition. The use of a PWM boost converter allows for a variable input and constant output. The output is regulated by the control circuit which adjusts the duty cycle of the gating pulse to maintain a constant output.
With the energy markets moving towards more environmentally friendly energy sources, the applications for dc/dc boost converters is increasing. Some of the typical applications of this converter can be found in the auxiliary power supplies of hybrid vehicles. Fuel cell–powered electric vehicles (FCPEV) require an energy storage device to start up the fuel cells and to store the energy captured during regenerative braking. Low-voltage batteries are preferred as the storage device to maintain compatibility with the majority of today’s automobile loads. A dc/dc converter is therefore needed to interface the low-voltage batteries with the fuel cell powered higher voltage dc bus system, because the present fuel cell technology lacks energy storage capability.
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