Energy Balance Associated with the Use of a Maximum Power Tracer in a 100-KW-Peak Power System

摘要

Design of a stand-alone photovoltaic (PV) system which includes batteries for energy storage requires not only sizing the array power output and battery storage capacity to meet the load, but also fixing the number of battery cells placed in series relative to the number of PV cells in series in order to keep the battery voltage in the neighborhood of the array maximum-power-point voltage during operation. When a maximum-power-point tracker (MPPT) is interposed between the array and the battery, the design task is simplified. The decision to use an MPPT depends primarily on the operating efficiency of the device. The recent development at MIT Lincoln Laboratory of low-cost maximum-power-point trackers capable of efficiencies greater than 98% at the 3-kW level broadens the range of applications where an MPPT can be used to advantage. Hourly simulation results for the 100-kW-peak PV stand-alone system under construction at Natural Bridges National Monument in Utah are compared for the cases with and without maximum power tracking to quantify the advantage of MPPT implementation. (ERA citation 05:011594)