Rectifier/invertor reactive component minimization

The problem of filter-component placement is considered in connection with the size and cost minimization of the reactive elements in a rectifier/inverter. First, the optimal placement is found for the filter elements. Given the terminal constraints, two circuit topologies are possible: one with a capacitor filter on the DC side and the other with it on the AC side. By calculating the component values, which minimize size for both the AC and DC side filters, and then repeating this calculation for a number of different switching strategies, it has been found that it is always desirable to have the capacitor filter on the DC side of the converter. Once the filter placement is specified, filter minimization becomes dependent only on the switching pattern. The frequency of the switching pattern has generally been limited by the switching losses of the devices used in the converter. However, by using zero-switching-loss inverter topologies, the use of uniform-sampled delta-modulation strategies is possible at a much higher switching frequency than those attainable in conventional converters. Filter ratings are reduced even further due to the higher switching speeds