Design and development of a smart power electronics Interface between DC and AC Grids

Introduction: Recent drops on the prices of power electronics devices made their commercialization possible. Also, developments in semi-conductor technology increased the capabilites of power electronics devices in terms of their voltage and current ratings. Therefore, power system operators are looking into ways of using power electronics interfaces for larger purposes.

One such application can be a "smart-interface" between the large AC grid and smaller DC grids. DC grids refer to smaller networks (microgrids) or large buildings that run on DC systems. It is a fact that most of the end-use products (laptops, mobile phones, LED lights or even Electric Vehicles) run on DC and most renewable energy based generators (such as PV or fuel cell, again Electric vehicles with vehicle to grid technology) generate DC as well. Considering this fact, there is a new trend to use DC grids as the mainstream in places wherever possible. This way, the power lost in DC-AC and AC-DC conversion will be saved and the systems will be more efficient and stable.

This project aims at designing a smart Point of Common Coupling (PCC) between a DC grid and and AC grid so that the integration can be performed smooth.

Method/Case Study: Firstly, current status of DC grids and their benefits will be reviewed. Then, the requirements for smooth integration between large AC grid (national grid) and the smaller DC grids will be outlined. Finally, a power electronics interface will be designed and developed to achieve above requirements. It is expected that Matlab/Simulink will be used as a simulation environment.

Results/Conclusions: The proposed project has the following contributions to knowledge:

  • Show benefits of DC grids in terms of efficiency and stability
  • Develop a smart interface between DC and AC grids which will operate at high voltage and current values and ensure smooth operation

Therefore, the proposed article will target an evident knowledge gap and provide guidance to power engineers working on DC/AC integration. The developed smart interface can be utilized to ensure that DC grids are behaving as constant load or generator to the larger AC grid. So that not only the benefits of DC grids will be reaped but also their deployment will be made very easy.