Limiting the Interference of Semiconductor Converters on the Power Supply Network Using Tuned Filters

This paper presents the results of simulation calculations of circuits with tuned filters for the 5th and 7th harmonic components and experiments on an electric drive with a 4 kW frequency converter, which were aimed at verifying the benefits in several variants of input filters. The benefits over series-arranged inductor suppression were assessed mainly in terms of the content of higher harmonic components of the inverter input current, in terms of THDi. The paper presents a quantitative comparison of the results obtained under different filter circuit conditions, i.e., the use of two tuned filters for the 5th and 7th harmonic components of the current, the use of a filter only for the 5th harmonic component of the current, the assessment of the influence of the RF filter on the effects of the tuned filters. The paper presents favorable results from simulations and experiments with substantial effects when using tuned filters, as the THDi of the inverter input current was reduced to values in the vicinity of 10% at a power factor of 0.99 after tuning the filters.