Shunt hybrid power filter control in power systems with interharmonics

A shunt hybrid power filter to compensate harmonic currents in power systems was designed and successfully tested by simulations and experiments. Nevertheless, low sub- and interharmonics were able to disturb its control. The result was a poor damping performance, an unstable DC-link voltage and high inverter currents. This paper presents different solutions to enhance the control of the filter. One solution is to stabilize the DC-link with a diode rectifier. Another or additional option is to detect the sub- and interharmonics separately and remove them from the reference signal. Finally, multiple dq-transformations are used to detect harmonics separately.