Overview and development of design concepts of AC power sources for measuring test equipment

This overview presents measures taken during R&D of three-phase AC power sources designed for phantom calibration of electric energy meters. Properties of portable and stationary version of power source, which are directly governed by the measuring requirements of energy meters, unlike conventional applications differ in terms of precision, time stability and total harmonic distortion (THD). The problem is described in detail in the case of four amplifiers with different topological approaches in regard to accuracy and minimum distortion of their output variables. The structure of topologies and the use of unique correction circuit - which is particularly suitable for the elimination of distortion caused by nonlinear loads - are described in detail. Illuminated is also the problem of parasitic DC voltage component, which is particularly acute due to the unbalanced magnetization of all magnetic component, either being the part of power source or device under test.