Voltage and Current Converter

Voltage-to-Voltage Converter:
                  Input                      Output
Vrms      0 ~ 280V        0.57 ~ 1.77V with 5VDC offset or
Vpp        0 ~ 400V        0.80 ~ 5.00V with 5VDC offset

Current-to-Voltage Converter:
                  Input                      Output
Irms      0 ~ 500mA      0.00 ~ 1.77V with 5VDC offset

      In order for the grid voltage and current flowing in the load can be read by the ADC microcontroller, voltage signal are converted using a voltage-to-voltage converter that is step-down transformer. While the current signal converted using current-to-voltage converter that is a step-up transformer which has very low inductance at primary coil and high inductance at secondary coil. For this purpose, we can use the adapter transformer. In this case, I_out and I_in fed to the low voltage coil and we get v0 and ground from high voltage coil as Figure 1.

Figure 1

      At the ADC input of microcontroller, we found clipper diode that can be utilized as a main component to build a zero cross detector that can be used to measure the period of input voltage. But in this study, the input voltage that is usually sinusoidal form will be entered as a whole, so that in future this system can be developed for the calculation of RMS values and power.

The Need for Phase Difference Measuring Instrument
Measure the Frequency of Grid Voltage rather than Measure the Frequency of Current

The Signal Conditioning
The use of the microcontroller ADC
Frequency Measurement
Phase Difference Measurement
Output Display Format