Design Of AC&DC Hybrid Micro-Grid Controller

At present, distributed generation technology has been gradually matured, and its application also continues to be expanded. Considering the distribution network security and stability, power balance, reliability of power supply and the power quality, the distribution network has limitations with grid-connected system of a large-scale distributed power supply. With the development of Micro-Grid technology, various difficult problems, such as grid-connected technology, have been solved. AC&DC hybrid Micro-Grid combines the advantages of DC Micro-Grid and AC Micro-Grid, which improves the distribution network flexibilities of DG, energy storage devices and load, and simplifies energy conversion process and its devices. The AC&DC hybrid Micro-Grid has become the main trend of Micro-Grid development in the future.In order to improve the amount of the connected DG to the power grid and ensure the security and the stability of the distribution network, applying potent management methods is of great importance. For the requirements of AC&DC hybrid Micro-Grid’s control and energy management, this thesis designed an energy management system architecture, which can achieve one or more AC&DC hybrid Micro-Grid’s energy control and management. This energy management system mainly consists of:the energy management unit on advanced level and the energy management unit on Micro-Grid’s level. The AC&DC hybrid Micro-Grid can be regarded as a special in distribution network, this thesis mainly aims at discovering how to design the Micro-Grid controller’s hardware and software, which controller is same as the energy management unit on Micro-Grid’s level.The energy management and control of AC&DC hybrid Micro-Grid is a complicated process, which includes a lot of communication data, data processing and system control tasks. Therefore, the embedded technology, designed hardware and software of Micro-Grid controller are employed in this thesis. The Micro-Grid controller hardware is composed of the core control unit, the peripheral interface, the power supply module and basic circuit modules. The core control unit is comprised of ARM, DSP and CPLD, which is regarded as a multi-core processing system. The peripheral interface provides many communication ports, which support various communication mode and communication protocol, multi-channel analog input and output conversion ports and multi-channel digital input and output ports. The Micro-Grid controller has many hardware interfaces, which makes data processing faster and the antijamming capabilities of peripheral interfaces more excellent.The software of Micro-Grid controller, based on Linux OS environment, mainly contains the communication protocols design, the analog and digital data input or output control, the data acquisition, the system control and so on. Micro-Grid controller is operated based on the Linux operating system which enables the controller to process multiple tasks simultaneously and improve the real-time performance of data.In addition, an AC&DC hybrid Micro-Grid experiment platform which consists of energy storage device, PV, loads and so on, is constructed in the thesis work. Moreover, an advanced energy management system is designed and an integrated test system of Micro-Grid controller is built at the same time. This thesis has tested the various performance of Micro-Grid controller through the relevant experiment. The result showed that the Micro-Grid controller had a stable operation, a quick data acquisition, a reliable data transmission, and accurate data calculation and energy management strategy execution.