The fundamental operating principle of an electronic energy meter (smart meter) relies on A/D converters or dedicated metering chips to perform real-time acquisition of user current and voltage. These signals are subsequently analyzed and processed by a CPU to calculate forward and reverse energy, peak and off-peak energy, or four-quadrant energy, with the results being output via communication interfaces, display screens, or other means.
Current sampling typically employs two distinct methods: Measurement of the live-wire current utilizes a manganese-copper shunt element, whereas measurement of the neutral-wire current employs a current transformer element.
The basic architecture of a complete, multi-rate, multi-functional fully electronic energy meter comprises converters for acquiring input voltage and current signals, a display screen, a data communication subsystem, non-volatile memory, a power supply, and a microcontroller embedded with the necessary operating software.