System and method for detecting connector faults in power conversion system

A system for detecting connector faults in a power conversion system comprising a plurality of series connected modules, each module having an input and an output connected by a connection contact, the system comprising:

• a loop connection provided between the output of a final module in the series and a first module in the series;
• a loop switch provided in the loop connection;
• a control unit in communication with each of the modules to control operation of the modules during a power conversion mode;
• loop current circuitry provided in one or more of the modules to generate a current flow from the output of the module;
• and
• voltage measurement circuitry within each of the modules provided to measure voltage of the input of the module relative to a local reference voltage and/or the output of the module relative to a local reference voltage;
• wherein the control unit is in communication with the loop switch, the loop current circuitry and the voltage measurement circuitry such that the control unit closes the loop switch when the system is not in power conversion operation, controls the loop current circuitry to generate the loop current and receives information from the voltage measurement circuitry of two or more of the modules, whereby the control unit compares the voltages measured for the input and/or output of each of the modules against the voltages measured for the output and/or input of the adjacent modules to determine the resistance of the connection contacts between the module and the adjacent modules.