Kretsanalysinstrument för envarvig spole

Sammanfattning: The thesis work was given on the request from ÅR Carton to produce a circuit able to measure current, voltage, frequency and the phase shift between the current and voltage in a one turn coil. The measured data was also to be sent to a computer for later use in analyzing the data. The most important question was which method to use to measure the current in the coil, suggested alternatives were between using a Rogowski coil or a Hall Effect sensor. The method was required to have minimal physical impact. Due to this, a Hall Effect sensor appeared to be the best choice. The measurement of the voltage was done by just measuring over the inductor, the resulting voltage was estimated as too high for the circuit to handle so a voltage divider was introduced to lower the voltage to a more appropriate level. The first tests of measuring the voltage and current showed that filters needed to be introduced to reduce some noise that was present in the signals. Both of the signals were converted to a DC signals with the help of RMS-to-DC converters. To measure the frequency and the phase shift of the sine waves a Schmitt trigger, the filter from before wasn’t enough to remove the noise completely so a comparator wasn’t sufficient to use, was introduced to convert each of the waves into square waves, which were then sent to an exclusive-or gate. These signals were then sent to a microcontroller which A/D converted the DC voltages and calculated the frequency and phase shift from the square wave of the exclusive-or gate. The microcontroller then sent the digital values and calculated data to a storage station using serial communication. Circuit diagrams were produced during the course of the project with the help of Microsoft Visio and Eagle Cad. A design for a printed circuit board was produced with Eagle Cad for the microcontroller and serial communication section of the circuit which was produced.