DESIGNING AND VERIFICATION OF FPGA BASED PROTOTYPE OF VSG

Abstract

Rotating inertia (rotational mass) of synchronous machines and a control system implemented on the rotating motion of synchronous generators will lead to stabilization of frequency of the voltage. But gradually as some part of synchronous generators are getting replaced by distributed energy resources and the inertia provided is getting decreased which leads to instability in grid frequency. One of the best way to add inertia is by emulating synchronous generator. One way to emulate synchronous generator is by imitating its swing equation which is called as Virtual Synchronous Generator(VSG). In the first stage of this dissertation implementation of VSG technology is executed in RSCAD and real-time simulation for various modes of operations is carried and results are included. The real-time simulations shows that the inclusion of VSG technology in microgrid has its significant effect on the stabilization of microgrid frequency. In the next stage the VSG controller block which gives the power to be delivered or received by the energy storage element(which is adjusted manually if there is no VSG) is implemented by using only digital blocks with the use of VERILOG HDL (Hardware Description Language) and the same code is dumped into a XILINX SPARTAN-3E FPGA board which now behaves as the VSG Controller. To Validate the VSG implemented on FPGA, this FPGA is connected to RTDS in place of VSG controller implemented in RSCAD by using HIL(Hardware In Loop) facility available in RTDS Simulator. Then Real-time simulations are carried for different mode of operations of microgrid and the results are compared with the results obtained in first stage and found that the performance of hardware implemented on FPGA is nearly same as that of VSG controller in RTDS simulator which shows that the VSG has significant effect on the frequency stabilization of microgrid during disturbances.