Manual

Maximum Power Point Tracking
975-0560-01-01 Revision B 1–3
Maximum Power Point Tracking
MPPT allows the charge controller to harvest the maximum energy available from
the PV array and deliver it to the batteries. The MPPT algorithm continuously
adjusts the operating voltage of the array to find the maximum power point. Input
power is measured and compared to the amount of input power harvested at the
previous operating voltage. The next adjustment to the operating voltage is
dependent upon whether the charge controller harvested more or less power
than it did at the previous operating voltage.
The algorithm is implemented by applying a variable load on the array—shown
by the power curve (solid line) in Figure 1-1—until it finds the peak power (the
point at which the combination of the operating voltage and current is
maximized), as indicated by MPP in Figure 1-1. The charge controller will
continue adjusting the operating voltage to stay on the maximum power point.
This is necessary as MPP changes throughout the day due to panel temperature,
panel shading, and sunlight intensity. The adjustments happen without
interruption of output power flow to the batteries.
Fast Sweep™ Shade Tolerant MPPT Algorithm
The charge controller has a Fast Sweep MPPT algorithm that frequently conducts
a very fast sweep of the full operational array voltage window to dynamically
determine the array’s maximum power point. This feature helps deliver
consistently high energy harvest for the system, including when the array is
partially shaded. For more information on shade-tolerant MPPT optimization, see
the white paper, “Photovoltaic String Inverters and Shade-Tolerant Maximum
Power Point Tracking: Toward Optimal Harvest Efficiency and Maximum ROI,”
available at http://www.se-renbu-docs.com/SEShadeTolerantWP.pdf.
Figure 1-1 Maximum power point curve
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