Low-Cost High-Performance Generator for Testing Current Transformers Based on Frequency-Domain Feedback

Characterizing the harmonic measurement performance of current transformers (CTs) requires a proper generator for applying realistic periodic current waveforms, mimicking those found in distribution grids. This paper proposes an approach for implementing a high-performance current generator, based on the usual, low-cost architecture consisting of a power amplifier, a transformer to boost its capability and a reference CT. Frequency-domain error feedback is adopted, with feedback gain set according to a preliminary frequency response measurement. This enables heavily mitigating the nonlinearity introduced by the current boost transformer, which no longer must be heavily overdesigned to reach high accuracy.