Research And Design Of A Photovoltaic Power Supply System With Bi-directional Inverter

As far as the current research and development of renewable energy be concerned, wind power and Photovoltaic (PV) energy is the most potential and available. But because of the presence of noise, the equipment of wind power only is suitable to be set in the remote and less populated areas. Meanwhile, the device of wind power must be set up on a large scale to achieve the goal of the economic benefits. Solar energy has its unique advantages, such as:the merits of abundant, pollution free, and broadly available. Silicon for manufacturing Photovoltaic panels is also the second most abundant element on Earth. Therefore, the development and utilization of solar energy will be bound to play an important role in the future transformation of the world’s energy structure and its importance can’t be matched by the other renewable energy.Today, the most of photovoltaic products on the market are designed just based on adequate solar energy to storage and utilization. For example:off-grid solar inverter, and so on. However, the solar exists a natural disadvantage, which is it is not possible a year for each day will be very adequate. So people save solar energy by batteries or other energy storage devices when energy is plenty. And then people use it when energy is inadequate. But, on the one hand energy storage devices only can store energy limited; on the other hand energy storage devices like a battery will cause secondary pollution to the environment.The topic of this research is the establishment of a photovoltaic solar power system based on bi-directional inverter. Which is known as bi-directional inverter is because it can control the power flow between dc bus and ac grid. When the output power from PV array is higher than DC load requirement, the inverter injects the surplus power into ac grid. When renewable energy can’t match load requirement, the inverter converts ac source to replenish the DC bus. It can be seen that this framework is no longer need battery module or storage equipment and also can make energy be used efficiency.The hardware circuit of this system is divided into the following three parts:Boost circuit with maximum power tracking, Full-bridge bi-directional inverter and MCU control board circuit. Boost circuit is commonly used in Boost circuit. The core of MCU control board is a PIC microcontroller.The software part of this system is written by use PIC C language and the inherent function library of the microcontroller. The perturbation and observation method is used to realize maximum power tracking. Unipolar high frequency switch modules and predictive current control method is used to reduce the harmonic interference of output current.Finally, this article shows that circuit simulation software is used to identify the feasibility of the proposed theory. And, the system is implemented to verify the validity.