Photovoltaic power optimizer with overvoltage protection control and rapid shutdown device

Methods and apparatuses enabling the optimizer of a PV system comprising a DC bus in a series-loop configuration to reliably select, use and control of the MPPT mode vs. the limited power mode vs. rapid shutdown mode when connected in a series-loop circuit to ensure the desired DC bus requirements are met and maintained. The improved system reliability responds to overvoltage during communication latency by preventing overvoltage event between any data or control communication. The methods and apparatuses detailed herein are especially useful for PV systems where the optimizers cannot access the output connection cable that connects and provides electricity to the DC bus (e.g., in a series-loop configuration).