Methods, systems and modules for testing uninterruptible power supply (ups) systems with multiple ups modules

An Uninterruptible Power Supply (UPS) module configured for inclusion in a UPS system, the UPS module comprising:

• a rectifier circuit, switchably coupled to an AC input to the UPS module, configured to provide a rectified output voltage to a DC link node;
• a DC-DC converter circuit, switchably coupled to a back-up power input to the UPS module, configured to provide DC voltage to the DC link node, based on the back-up power input;
• an inverter circuit, coupled to the DC link node, configured to provide an AC output for the UPS module based on the rectified output voltage or the DC voltage;
• and
• a control circuit configured to activate an idle state for the UPS module, and to provide a UPS module test power input to the rectifier circuit, the DC-DC converter circuit, and/or the inverter circuit, and configured to determine a UPS module test power response to the UPS module test power input, and to compare the UPS module test power response to a predetermined UPS module test power response.