Synthesis of Dynamic Errors Correcting Algorithm for Auto–Balancing Bridge Methods

Autobalancing bridge method is widely used to measure the impedance of various objects in many fields of science and technology. The article presents an innovative approach to address auto-balancing bridge dynamic errors to extend the range of operating frequencies. The mathematical model of auto-balancing bridge, implemented using operational amplifier, was analysed, obtaining its simplified version taking into account the most important sources of errors. The concept was developed and the algorithms for compensation of the impact of dynamic errors on the measurement of admittance components were synthesized. The presented algorithms allow the correction of admittance measurements only based on “raw” results obtained with the use of an auto-balancing bridge. Methodology was described and numerical simulation was carried out on a selected example. As shown in the paper, the developed correction algorithms allow extending significantly (400 times) the range of admittance measurement frequencies. These algorithms do not require interfering the auto-balancing bridge structure, but only engage the computing power of modern measurement channels.