Patent ID: 6999329

Claim:
A method for parallel-connected inverter modules, whereby two or more inverter modules (A, B, C) are connected in parallel to feed the same load, each inverter module (A, B, C) comprising two or more output phases (u, v, w) for supplying electric power into a two or more phase load, the method comprising: determining the temperature (T Au , T Av , T Aw , T Bu , T Bv , T Bw , T Cu , T Cv , T Cw ) of each output phase (Au, Av, Aw, Bu, Bv, Bw, Cu, Cv, Cw) in each inverter module (A, B, C), wherein the method further comprises the steps of: comparing the temperatures of the output phases in each inverter module with the temperatures of the same output phase in the other parallel-connected modules, and generating an alarm signal if the temperature of the output phase in an inverter module differs from the temperatures of the same output phase of the other inverter modules by more than allowed by a predetermined limit.