Development of 1kV DC voltage measurement circuit for solar energy system

Previous studies for measuring the high direct voltage focused on the resistive voltage divider or the hall voltage sensor. The cost of the hall voltage sensor is expensive and additional shielding method must be taken into account when using the voltage divider. In this paper, resistive voltage divider, integrated operational amplifiers and photocouplers are used cooperatively to design the 1kV DC voltage measurement circuit. Two photocouplers are used together with each current transfer ratio (CTR) balance each other out to reduce the influences on the high input direct voltage and the low output direct voltage ratio. The experimental results, with carefully setting the offset and gain calibration values, show that measurement circuit can get a good measurement accuracy with low cost for solar energy system.