CSLB C-46 Solar ContractorPhotovoltaic System InstallationMedium
A solar designer is laying out a rooftop PV system. The building has several vents and chimneys that will cause intermittent shading on portions of the array at different times of the day. To optimize energy production under these conditions, which component is most effective at mitigating the effects of partial shading on individual modules?
- ACentral inverter with a single MPPT.
- BMicroinverters.
- CString inverter with a single MPPT.
- DOversized DC-to-DC converter.
Show answer & explanationAnswer & explanation
Correct answer: B. Microinverters.
Microinverters convert DC to AC at the module level, meaning each module has its own Maximum Power Point Tracking (MPPT). This allows each module to operate at its optimal power point independently, significantly reducing the impact of partial shading on the overall array output compared to string or central inverters with fewer MPPTs.
Why the other options are wrong
- A. A central inverter with a single MPPT would suffer the most significant power loss from partial shading across the entire array.
- C. A string inverter with a single MPPT would have the entire string's output limited by the shaded module.
- D. An oversized DC-to-DC converter is not a standard solution for partial shading mitigation and doesn't inherently provide module-level optimization.
Microinverter Shading Mitigation
Microinverters perform Maximum Power Point Tracking (MPPT) at the individual module level, allowing each module to produce its maximum power output independently, even when other modules are shaded.
- Maximizes energy harvest in shaded conditions.
- Each module operates independently.
- Reduces losses from partial shading.
Memory trick: Shade's a pain, but module-level tech helps gain.