SLUAAP0 june   2023 BQ25798

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2How MPPT and VINDPM Works on Solar Battery Chargers
    1. 2.1 Buck MPPT
    2. 2.2 Boost MPPT
    3. 2.3 Buck-Boost MPPT
  6. 3Summary
  7. 4References

1 Introduction

The output voltage of a solar panel is tightly linked to the current drawn from the solar panel. If too much current is drawn from the solar panel the output of the solar panel will crash. The key to successful solar panel utilization is to find what is called the Maximum Power Point (MPP). At the MPP the maximum amount of power available from the solar panel is delivered [1], [2], [3]. Figure 1-1 shows Current vs. Voltage and Power vs. Voltage curves. Note how there is a clear MPP of approximately 7W and 13.5V for the Power vs. Voltage curve. Increasing or decreasing the panel voltage beyond this point lowers the panel output power.

GUID-20230411-SS0I-H9C1-QX0S-MVWFGVRD6BLJ-low.svgFigure 1-1 Sample I-V and P-V Curve

Different switch mode topologies are used to accommodate the different input and output voltages as well as allow for the higher efficiencies of a switching charger. In this application note, the buck, boost, and buck-boost topologies are discussed.