No Clipping Losses Despite an Undersized Inverter

Summary

A comparison of inverters with a one to one ratio and a two to one ratio. Two to one ratio inverters are less lenient to show clipping losses. 

240W Inverter	600W Inverter (for two panels)

Both of these inverters are undersized (DC/AC ratio > 133%). Note the 600W output power inverter is split between two panels and therefore the dc/ac ratio is 410/300.

This split between two panels is the key difference that arises.

Panels in Series vs. Individual Inputs

• In systems where a micro inverter handles two panels in series, the combined voltage increases while the current remains the same. This can:
  • Shift the operating point of the inverter.
  • Reduce current-related constraints, potentially reducing clipping losses.
• This contrasts with a micro inverter that handles one panel per input, where the panel's entire DC output goes directly to the inverter without sharing.

Inverter Maximum Voltage Rating

• Inverters have a maximum voltage rating that influences their behavior:
  • If the system design results in high voltage close to this maximum, the inverter might derate (reduce its output) to protect itself, especially at high temperatures.
  • If the operating voltage is lower (due to fewer panels in series or other design factors), the inverter avoids such derating losses.

Ultimately two panels in series creates a higher voltage that allows the inverter to handle more power without exceeding its current-handling limitations, which are often a bottleneck in power conversion. This balance helps prevent the inverter from reaching its maximum output prematurely. Coupled with the fact that loses may be labelled under derating losses the two panels in series can show no clipping losses in the summary tab.