CSLB C-46 Solar ContractorPhotovoltaic System InstallationMedium
A solar designer is creating a system layout for a residential rooftop with multiple small obstructions (e.g., vents, chimneys). To maximize energy harvest and minimize the impact of partial shading, what is the most effective inverter technology to specify?
- AMicroinverters at each module.
- BString inverter with multiple MPPT inputs.
- CCentral string inverter with a single MPPT.
- DHybrid inverter with battery backup.
Show answer & explanationAnswer & explanation
Correct answer: A. Microinverters at each module.
Microinverters perform MPPT at the individual module level. This means that if one module is partially shaded, it only affects the power output of that specific module, allowing other unshaded modules to continue producing at their maximum potential, thus maximizing overall system output.
Why the other options are wrong
- B. While better than a single MPPT, a multi-MPPT string inverter still manages strings of modules. Shading on one module in a string affects that entire string, not just the single module.
- C. A single MPPT string inverter would suffer significant power loss across the entire string if even one module is shaded.
- D. A hybrid inverter's primary function is battery integration, not specifically shading mitigation for complex arrays.
Microinverter Shading Mitigation
Microinverters optimize power at the individual module level, effectively mitigating the impact of partial shading by ensuring that only shaded modules experience reduced output, while others continue to produce maximally.
- MPPT is performed for each individual module.
- Shading on one module does not affect the performance of other modules.
- Maximizes energy harvest in complex or shaded layouts.
- Higher initial cost but often better performance in challenging conditions.
Memory trick: Microinverters Make Minimizing Shading Maximize Output.