A control strategy for
distributed power generation modules in a power
system that varies the line frequency or
voltage according to a predetermined pattern to cause a PV
inverter to modify its
power output and thereby avoid overcharging a battery. When the power
system operates in islanded mode, the AC load demand can be lower than the available energy from the PV array, causing the battery to become overcharged. To avoid this
scenario, a
hybrid inverter executes a pattern generator
algorithm that varies the line frequency or
voltage linearly, exponentially or any mathematical function or look-up tables. The PV
inverter executes a
pattern detection algorithm that detects the linear, exponential, or any mathematical function or look-up table change in the line frequency. In response, the PV inverter modifies its
power output until an overcharging condition of the battery is removed. The line frequency /
voltage can be varied within the anti-
islanding limits to avoid premature disruption of the power
system, and no additional settings are required at the device level in order to operate in any mode of operation: islanded, grid-connected or genset-connected.