What is the current working principle of smart meters?

The current working principle of smart meters is mainly based on real-time sampling of the user's supply voltage and current, and then using a dedicated energy meter integrated circuit to process the sampled signal, finally converting it into a pulse output proportional to the electrical energy, and processing and controlling it through a microcontroller to display the pulse as electricity consumption and output it. The following is a detailed analysis of the working principle of smart meters:

1、 Sampling stage

Smart meters provide real-time sampling of users' voltage and current through built-in transformers (or splitters, voltage transformers) or direct sampling resistor networks. The transformer sampling method uses voltage transformers and current transformers to collect voltage and current signals respectively, while the direct sampling method uses a high thermal stability resistor voltage divider network to obtain voltage signals and uses manganese copper sheets with low temperature coefficient of resistance for direct current sampling.

2、 Signal processing stage

The voltage and current signals obtained from sampling are processed by specialized integrated circuits for electric energy meters, such as metering chips. The integrated circuit contains an A/D converter (analog-to-digital converter) that converts analog signals into digital signals and performs digital integration operations. During this process, the number of pulses (i.e. pulse constant) emitted by the A/D converter per unit time directly determines the measurement accuracy of the electricity meter.

3、 Calculation and Control Stage

The processed digital signal is sent to a microcontroller (microprocessor) for further processing and control. The microcontroller calculates the electricity data based on preset algorithms and rates, and stores the results in the storage module. At the same time, the microcontroller is also responsible for controlling the display module and displaying the power data in digital or graphical form.

4、 Communication and Data Transmission Stage

The smart meter also has a communication module for data transmission with the host or remote management system. The communication module can adopt various communication methods, such as power line carrier communication (PLC), MBUS, RS485, wireless LoRa, etc. Through these communication methods, smart meters can transmit real-time electricity data, alarm information, status information, etc. to remote management systems, achieving remote monitoring and management.

5、 Other functional modules

In addition to the basic working principle mentioned above, smart meters also have some other functional modules, such as safety modules, clock modules, and power on/off modules. The security module is used to implement functions such as secure storage of data, data encryption/decryption, and two-way identity authentication; The clock module provides real-time clock for the system as the basis for power freezing and rate switching; The power on/off module is used to control the user's power on/off operation.

In summary, the working principle of smart meters is a complex and intricate process involving multiple links such as sampling, signal processing, calculation and control, communication and data transmission. These links work together to achieve accurate measurement and remote management of electrical energy.