ANALYSIS OF MEASURING CIRCUITS WITH CAPACITIVE CONVERTERS
Boris Mamikonyan
ANALYSIS OF MEASURING CIRCUITS WITH CAPACITIVE CONVERTERS
MAMIKONYAN BORIS
Doctor of technical sciences, Professor,
Electro-Energetic, Information and Automated Systems Department,
National Polytechnical University of Armenia, Gyumri Branch,
2, M. Mkrtchyan st., 3103, Gyumri, Republic of Armenia
bomam@yandex.ru
Capacitive sensors (CS) are widely used in information-measuring and controlling systems for conversion of mechanical quantities and many technological parameters. In recent years when MEMS-technology and devices have emerged, which combine microelectronic and micromechanical components, the application of capacitive sensitive elements has immensely increased. Wide application of CS demands that simple, precise and reliable meters of capacitive primary converter (PC) be developed, which should be compatible with current microcontroller devices for processing the information and controlling the measurement process. The measuring circuit (MC), which along with the PC is a constituent part of CS, is to ensure that the measurement result of the PC informative parameter is invariant to both destabilizing factors, affecting the PC (e.g. voltage and frequency of the feeding generator), and its non-informative parameters.
There has been given solution of the technical problem of invariant measurement of the capacitive primary converter (PC) parameters on the alternating current without application of potential-current signals. As a measuring circuit there has been used the voltage divider circuit and as an output signal the angle of phase shift between the two output voltages of the MC has been used. To form the output signal, temporary separation of the measurement channel has been used. The advantages of the phase method are mostly due to possibilities of using microcontrollers. In the technical solutions of the problems under consideration the microcontroller regulates the measurement process and processes the measurement results. The proposed technical solution is simple in practical realization and can ensure high measurement accuracy with the limit of permissible basic relative error, which doesn´t exceed 0.1%.
1. 24/25, N. Shnorhali st., 3103, Gyumri, Republic of Armenia