According to an aspect of the present invention, there is provided a distributed power system including a DC power source and a power module. The power module includes an input coupled respectively to the DC power source and an output. An inverter is coupled to the output. The inverter converts power input from the output of the power module to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power module. During operation of the distributed power system, in some embodiments, the signaling mechanism may superimpose a signal on the output of the power module. The signaling mechanism may include a switch integrated with the inverter, the switch modulating the signal onto the output of the power module. A receiver integrated with the power modules receives the signal from the inverter. Alternatively a detection mechanism in the power module detects a signal at the frequency of the electrical grid. Alternatively, a signal from the electrical grid is detected in the output of the power module at a higher frequency up-converted from the frequency of the electrical grid. Alternatively, a detection mechanism in the power module detects a switching frequency of the inverter. The power modules are may be configured for operation in a safety mode, and during the safety mode, the power at the output of the power module, the voltage across the output of the power module, and/or the current flowing through it, are limited so as not to endanger personnel. The power module may include a detection mechanism wherein during operation of the distributed power system, the detection mechanism detects a signal from the inverter. Based on the signal, the operation of the power module is varied from the safety mode of operation to a normal mode of operation for converting power of the DC power source from the input to the output of the power module.