Damping potential of single-phase bidirectional rectifiers with resistive harmonic behaviour

To reduce the voltage distortion in a distribution network, parallel (shunt) harmonic impedances (SHIs) can be strategically positioned in the network. However, to avoid the additional cost of adding SHIs to the distribution network, the SHI function can be implemented as it secondary function of convertors connecting loads or generators to the mains. A control strategy for a single-phase bidirectional full-bridge AC-DC convertor is proposed. This control strategy allows a fixed resistive impedance to be programmed for harmonics, independent of the direction of the fundamental power flow. Hence, the bidirectional rectifier obtained behaves, as a secondary function, like a resistive SHI, providing damping for resonances and resulting in an overall improvement of the voltage distortion in the distribution network. The theoretical results obtained are verified by using an experimental test setup. The Superior damping potential of the experimental bidirectional rectifier with the proposed control scheme is demonstrated by a comparison with experimental results previously obtained for 'classical' control schemes

The location of a resistive shunt harmonic impedance along a distribution feeder and its influence on harmonic propagation

Although complete compensation is only possible using true active filters, resistive shunt harmonic impedances (SHI) have been shown to provide a considerable reduction of the harmonic propagation. In this paper, the harmonic mitigation potential of a resistive SHI is discussed concerning its influence on the voltage distortion profile along a typical distribution feeder, with the location of the SHI along the feeder as a parameter. Although the distortion values are dependent on the SHI location, it is shown that the end of the feeder is generally a good location to install the SHI, especially when the power system parameters can vary or are unknown. Calculations are performed on a typical radial distribution feeder. Both the power factor correction capacitors and the non-linear loads are concentrated in single nodes. The linear loads are disconnected to obtain the worst case for the voltage distortion. Also some measurements on a scale model of a typical distribution feeder are done and the experimental results confirm the results obtained from simulations