This paper proposes a Flying Capacitor DC/DC Boost Converter (FCBC) with a small capacitance of the flying capacitor. As a result the size and weight of the proposed converter can be reduced. The capacitance of the flying capacitor is designed based on switching device voltage rating and regardless of the output voltage ripple influences. Moreover, the achieved maximum efficiency of the designed 3-level FCBC is 98.5% at the output power of 1 kW. Finally, the effectiveness of small capacitances of the flying capacitor in the 3-level and 5-level FCBCs are investigated. The characteristics of the distorted voltage across an input voltage source and an input inductor and the distorted current to the output side which is an output capacitor and a load are investigated with several capacitances of the flying capacitors for 3-level and 5-level FCBCs. As a result, it is experimentally confirmed that the distortion of the voltage across the input voltage source and the input inductor is drastically reduced by increasing the number of level.On the other hand, the distortion of the current to the output side which is the output capacitor and the load is almost same even the number of level is increased. Therefore, the experimental results show that small capacitance of the flying capacitor can be used in the n-level FCBC.Index Terms-flying capacitor, output voltage ripple, multi-level flying capacitor boost converter.

Abstract--Solar power generation had been used as a renewable energy since years ago. Residential that uses solar power as their alternative power supply will bring benefits to them. The main objective of this project is to develop an automatic solar tracking system which will keep the solar panels aligned with the Sun in order to maximize in harvesting solar power. The system tracks the maximum intensity of light. When the intensity of light is decreasing, this system automatically changes its direction to get maximum intensity of light. LDR light detector is used to trace the coordinate of the Sun. While to rotate the appropriate position of the panel, a DC geared motor is used. The system is controlled by two relays as a driver and a microcontroller as a main processor. This project is covered for a single axis and is designed for residential usage. Finally, the project is able to track and follow the Sun intensity in order to get maximum power at the output regardless motor speed.Index Terms--solar tracking, sun tracking.

The purpose of the present paper is to analyze the input inductor design and to establish the relationship between the capacitance of the flying capacitor and the output voltage ripple in order to reduce the size and weight of the flying capacitor DC-DC boost converter (FCBC). The inductance of the input inductor is designed by considering the maximum input current ripple, and the experimental results are used to confirm that the input current ripple is within the designed value. Furthermore, according to the design specifications, the required inductance of an input inductor is approximately 25% of that of a conventional two-level DC-DC boost converter, and the required inductor core volume is approximately 35% of that of a conventional two-level DC-DC boost converter. Moreover, the capacitance of the flying capacitor and the output voltage ripple are confirmed to be independent of each other. Theoretically, this is because the time constant of the output capacitance and the output resistance of the FCBC is larger than the switching period of the switching frequency. This finding is confirmed by the simulation and experimental results of the present study. On the basis of this finding, the capacitance of the flying capacitor can be estimated and designed without considering the output voltage ripple. Moreover, the achieved maximum efficiency of the designed FCBC is 98.5% of the output power at 1 kW.

The paper proposes a Marx topology DC-DC boost converter (MTBC) with a high boot ratio, where a parallel connection is applied on the input side in order to reduce the conduction and copper losses while a series connection is applied on the output side in order to reduce the voltage stress on switching devices. With the proposed circuit configuration, the high boost ratio DC-DC converter achieves high efficiency. A three-stage MTBC with a boost ratio of 8.33 between the input and output voltages was designed and constructed. A maximum efficiency of 94.5% was achieved with the designed three-stage MTBC. The loss analysis showed that the iron and conduction losses were dominant. The volume analysis showed that the proposed three-stage MTBC requires approximately 23% less of a total volume compared to the conventional isolated DC-DC converter with a two-series-output-rectifier (ICSR) while reducing the power loss of semiconductor devices.