Abstract: For independent load sharing of current harmonics between parallel inverter units (1a, 1b, 1c) in an AC power system without intra-unit control signal communication, where each inverter unit is connected to a common load (8) through a separate impedance (7a, 7b , 7c), amplitude and phase of a selected current harmonic is determined for each unit by processing of a current value M measured in a power output line (51a, 51b, 51c) from the unit before the separate impedance and is compared with amplitude and phase of a feed-back voltage or current (V) from the power output line to produce an error signal, which is used for determination of a control signal component for the selected harmonic for incorporation into a control signal input to control means for controlling the content of said harmonic in the voltage and/or current supplied by the inverter unit (1a, 1b, 1c) to the common load (8).

Abstract: For independent load sharing of current harmonics between parallel inverter units (1a, 1b, 1c) in an AC power system without intra-unit control signal communication, where each inverter unit is connected to a common load (8) through a separate impedance (7a, 7b, 7c), amplitude and phase of a selected current harmonic is determined for each unit by processing of a current value M measured in a power output line (51a, 51b, 51c) from the unit before the separate impedance and is compared with amplitude and phase of a feed-back voltage or current (V) from the power output line to produce an error signal, which is used for determination of a control signal component for the selected harmonic for incorporation into a control signal input to control means for controlling the content of said harmonic in the voltage and/or current supplied by the inverter unit (1a, 1b, 1c) to the common load (8).