MPPT (Maximum Power Point Tracking)
Control algorithm in an inverter or charge controller that continuously adjusts operating voltage so a PV array delivers its maximum available power.
A PV array has a non-linear current-voltage curve. Power, the product of voltage and current, peaks at a single point, the maximum power point, which shifts as irradiance and cell temperature change. Current rises almost linearly with irradiance, while voltage falls with rising temperature (see temperature coefficient).
The MPPT stage, a DC-DC converter controlled by software, searches for that point many times per second. Common algorithms:
- Perturb and observe: nudges voltage and keeps the direction that raises power.
- Incremental conductance: compares dI/dV with −I/V to locate the peak.
- Periodic global sweep: scans the full curve to escape local peaks created when bypass diodes activate under partial shading.
Modern inverters achieve static tracking efficiency above 99% (EN 50530 test). Multiple MPPT inputs let strings with different orientations or lengths operate independently; module-level electronics such as microinverters and power optimisers push tracking down to every module. Battery charge controllers with MPPT harvest 10–30% more than simple PWM controllers, especially in cold weather.
Related terms
All terms →- String inverter
An inverter that converts the DC output of one or more series strings of PV modules into grid-synchronised AC, typically with several independent MPPT inputs.
- Microinverter
A small inverter mounted behind one or a few PV modules that converts their DC output to AC at module level, with individual power point tracking.
- Power optimizer
A module-level DC-DC converter that tracks each panel maximum power point and conditions its output before it enters a string inverter.
- Bypass diode
A diode wired in parallel with a group of cells in a PV module that lets string current flow around shaded or faulty cells, preventing hot spots.
- String (PV)
A group of PV modules wired in series so that their voltages add up while the current stays that of a single module.