Microinverter

Unlike a string inverter that combines all panels in a single series circuit, a microinverter performs MPPT tracking independently per panel, so the system output is not dictated by the worst-performing panel.

In a string inverter architecture, panels are connected in series to form a single "string": if one panel is partially shaded — from a chimney, an antenna, or a neighbour's roof — the output of the entire string drops to match the weakest panel. A microinverter breaks this dependency. Because each panel has its own inverter and MPPT algorithm, partial shading only reduces the output of the affected panel; the other panels keep operating at their optimal power point.

The consequence of this architecture is price. The cost of a microinverter system is generally 30-50% higher than a comparable string inverter system [Indonesian market prices 2024-2026, with the Enphase IQ8, APsystems DS3, and Hoymiles HMS series as reference benchmarks]. This premium covers the additional inverter units, special connectors, and more labour-intensive installation. As compensation, microinverters offer per-panel production monitoring in real-time and tend to carry a longer product warranty — generally 25 years, compared with 10-12 years on a mid-range string inverter.

Microinverters are most relevant for roofs with a complex profile: multiple planes, different orientations, or unavoidable shading obstacles.

Indonesian PLTS Application Example

A two-storey house in Surabaya with a roof facing three directions and an antenna mast on the east side is a typical candidate. If 10 panels of 400 Wp are installed with a 4 kWp string inverter and 2 panels are frequently shaded by the antenna, the production of the entire string can drop 15-25% at peak hours. With microinverters, the 8 unshaded panels keep producing at full output. At Surabaya's PSH of 4.9 kWh/m²/day [NASA POWER 1984-2023], the difference in annual production can materially affect the return-on-investment decision.