FIG. 1B illustrates one serial string 103 of DC sources, e.g., solar panels 101a-101d, connected to MPPT circuit 107 and inverter 104. The current versus voltage (IV) characteristics is plotted (110a-110d) to the left of each DC source 101. For each DC power source 101, the current decreases as the output voltage increases. At some voltage value, the current goes to zero, and in some applications the voltage value may assume a negative value, meaning that the source becomes a sink. Bypass diodes (not shown) are used to prevent the source from becoming a sink. The power output of each source 101, which is equal to the product of current and voltage (P=i*V), varies depending on the voltage drawn from the source. At a certain current and voltage, close to the falling off point of the current, the power reaches its maximum. It is desirable to operate a power generating cell at this maximum power point (MPP). The purpose of the MPPT is to find this point and operate the system at this point so as to draw the maximum power from the sources.

In a typical, conventional solar panel array, different algorithms and techniques are used to optimize the integrated power output of system 10 using MPPT module 107. MPPT module 107 receives the current extracted from all of solar panels 101 together and tracks the maximum power point for this current to provide the maximum average power such that if more current is extracted, the average voltage from the panels starts to drop, thus lowering the harvested power. MPPT module 107 maintains a current that yields the maximum average power from system 10.