Bi-directional energy flow grid-tied inverter

• Main Author: Zhu, Dexuan.
• Other Authors: Choo Fook Hoong
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/54687
• Institution: Nanyang Technological University

A hybrid DC-AC smart grid system has been designed and setup in the Water and Energy Research Laboratory (WERL). The hybrid DC-AC grid system consists of an AC grid and a DC grid and operates in both grid-tied and autonomous mode. In this hybrid grid, various renewal energy sources are connected to the de grid while the ac grid is connected to the public grid. The bi-directional grid-tied inverter bridges the gap in the hybrid system where it is used to convert power from dc to ac as well as from ac to dc depending on the power supply and demand profile. Based on different requirements of system, some strategies should be considered in the controller. At normal operating condition, the global power sharing strategy is needed to transfer the power and also this strategy could make the transfer more stable. If there is something wrong in DC grid or the battery is fully charged or discharged, which makes the DC bus voltage unstable, DC bus voltage regular strategy is needed to maintain the DC bus voltage. If the load power requirement is larger than the power that DC and AC source could supply, it should shed the non-priority load and supply the priority load first. So load shedding strategy is needed. Choosing control strategies for the algorithm should be designed by detecting the system operating conditions and selecting the correct strategy, hence, the objective is to design the controller which could meet this requirement.