Simulated Annealing Characterization of Equivalent Circuit Models for Precision Coaxial Current Shunts

Equivalent circuit model characterization of shunts is an optimization problem where the solution consists of finding a simplified circuit model that best describes the impedance measurements on different frequencies of a shunt. A model consists of a model scheme and its parameters. This paper proposes the LCR-SAFit algorithm which searches for the best solution by minimizing the complex mean squared error across different model schemes and real measurements. LCR-SAFit uses two simulated annealing algorithms, SA-Approx and SA-FineTune, for finding the parameters of a model scheme. SA-Approx is used for approximating the area of the global minimum. SA-FineTune additionally fine-tunes the previously found solution. Impedance measurements for 7 different shunts were made using an LCR-meter for frequencies up to 10 kHz.