S.D. Gamini Jayasinghe

Direct Integration of Battery Energy Storage Systems in Distributed Power Generation

In this paper, a wind energy conversion system interfaced to the grid using a dual inverter is proposed. One of the two inverters in the dual inverter is connected to the rectified output of the wind generator while the other is directly connected to a battery energy storage system (BESS). This approach eliminates the need for an additional dc-dc converter and thus reduces power losses, cost, and complexity. The main issue with this scheme is uncorrelated dynamic changes in dc-link voltages that results in unevenly distributed space vectors. A detailed analysis on the effects of these variations is presented in this paper. Furthermore, a modified modulation technique is proposed to produce undistorted currents even in the presence of unevenly distributed and dynamically changing space vectors. An analysis on the battery charging/discharging process and maximum power point tracking of the wind turbine generator is also presented. Simulation and experimental results are presented to verify the efficacy of the proposed modulation technique and battery charging/discharging process.

Evaluation of Low Voltage Ride-Through capability of synchronous generator connected to a grid

The grid compliance of generators has been largely focused on wind power generators in literatures. With the increase in installation of distributed power systems, the dynamic performance of governor controlled prime mover driven generators might be affected. This paper discusses the Low Voltage Ride Through (LVRT) compliance of a governor controlled generator connected to a ring structure transmission system. The LVRT compliance of the generator is examined through case studies for various scenarios. This simulation study implies that a particular prime mover driven generating unit may be able to comply with the LVRT requirement in one grid code, but may fail to comply with the LVRT requirement in another grid code.