Interleaved DC-DC converter with lead-acid storage batteries for power regulation of grid-connected variable-speed wind turbine

This paper presents a small-scale grid-connected wind power conversion system(WECS). The fluctuating output power of the WECS is regulated and kept constant using an interleaved dc-dc converter with 8 lead acid storage batteries connected in series. The control of the battery management system is designed to optimize the use of the 12V, 99Ah advanced Thin Plate Pure Lead (TPPL) lead acid battery, and to prolong the life of the battery with maintaining the integrated wind power delivered to the grid constant. Maximum power point tracking(MPPT) is incorporated into the battery management system, to maximize the output power of the wind turbine driven 1.5 kW interior permanent magnet synchronous generator(PMSG). Instead of using the two-level voltage source inverter, the three-level one is designed and constructed for the grid-integration of the variable-speed wind turbine to highly reduce the switching frequency without increasing the ripple components in the grid-side current of the LCL filter. The experimental results confirm that the proposed control of lead acid storage battery makes the overall system more reliable and cost effective.