Smart meters are intelligent devices that people have been working on for many years to enable remote reading of electricity consumption and energy. They are also the basic unit of the automatic meter reading (AMR) system, and the automatic meter reading system composed of smart meters is an important step in realizing the smart grid.
Smart meter systems enable electricity suppliers to improve service quality while reducing management costs. This helps utility providers and governments reduce power losses, optimize energy consumption, manage demand for precious energy resources, and allows users to take full advantage of various electricity plans (such as time-of-use pricing) to save money and enjoy various conveniences. A well-developed smart meter system will greatly facilitate people's daily lives, while improving the effective distribution and utilization of electrical energy, generating significant business opportunities and social benefits in building an energy-saving and resource-conserving society and promoting energy conservation and emission reduction.
The implementation of smart meters utilizes several key technologies, including power line carrier communication (PLC) technology, dedicated communication lines (such as RS485 bus technology), and wireless communication technology. Currently, PLC technology is the mainstream technology for AMRs (Automatic Memory Controllers), therefore, the development and promotion of smart meters are closely related to the development of PLC technology.
Power line carrier communication systems use power transmission lines as the medium for transmitting carrier signals, which seems like an easy-to-implement and widely adopted solution. However, power transmission lines are not ideal carrier signal transmission media. Power lines significantly attenuate carrier signals, and interference from numerous electrical devices along the lines can have a total power far exceeding the carrier signal power, sometimes by hundreds of times. Therefore, establishing a reliable communication system on power lines is extremely challenging. Without proper system design, communication often fails completely or only at extremely low data transmission rates.
The image shows the functions of a smart meter system based on PLC technology.
Early power line carrier communication technology was mostly implemented using discrete components and general-purpose integrated circuit chips. Due to the limited hardware resources at the time, it was impossible to use advanced digital signal processing technology to generate complex carrier signals and process received carrier signals, let alone form a large-scale communication network on power lines. Therefore, early carrier communication systems could only achieve simple point-to-point communication and small-scale systems.
With the development of integrated circuit technology, advanced power line communication technology is gradually being implemented using dedicated integrated circuit chips, evolving from simple dedicated chips to multifunctional system-on-chips (SoCs) with multiple embedded CPU cores. Advanced power line communication chips possess powerful computing capabilities, making the implementation and management of large-scale communication networks possible.
Despite the gradual improvement in hardware conditions and resources for communication technologies, due to the unique characteristics of power line communication, especially the special conditions of power lines in China, without a good design (including digital signal processing algorithms and network system management), it is still difficult to guarantee the reliability of power line carrier communication and its large-scale application.
This is reflected in the development history of power line carrier communication in China over the past decade. Some previous technical solutions underestimated the difficulties of power line carrier communication and were put into use without extensive research, analysis, computer simulation, and field experiments. Other technical solutions simply copied those used for wireless communication or certain power line communication solutions that were effective on power lines abroad.
After more than a decade of exploration and the accumulation of experience and lessons learned, more and more industry professionals have gradually reached the following consensus: technologies effective for power lines abroad may not be fully applicable in China; technologies effective in wireless communication may not be applicable to power line communication; and a viable power line carrier communication technology solution must incorporate elements of network communication.
The first two points above tell us that we cannot mechanically copy technologies or solutions from different regions and fields. The third point foreshadows the development direction of power line carrier communication technology and suggests that technical solutions without network functionality are difficult to promote on a large scale and remain competitive. In the future, power line carrier technology will further improve its integration and reduce costs, while also developing towards multifunctional integrated network systems. Control response speed and communication speed will be further improved, and distributed processing will greatly accelerate this process.
Furthermore, with the accelerated development of various power line carrier communication applications, the sharing of power line resources will become a prominent issue. Therefore, a viable carrier communication technology and system solution must also be able to solve the problem of sharing communication media with various power line carrier communication application systems.
Riscon Microelectronics (Shenzhen) Co., Ltd. is one of many companies dedicated to promoting power line carrier communication applications. As a design company specializing in power line carrier communication chips, Riscon Microelectronics always prioritizes the interests of its chip and system users. This principle permeates the entire chip and system R&D process, extending to the design, integration, and testing of chip application reference circuits and systems, as well as mass production and field installation. Furthermore, it considers future system maintenance and upgrades for its customers. Currently, Riscon Microelectronics is one of the main power line carrier chip suppliers for the State Grid's smart meter system construction in China.
In the early stages of chip design, Ruiscom Microelectronics conducted extensive research, drawing on the advantages and disadvantages of various technologies used in other communication fields (such as mobile communication and satellite communication), taking full account of the special characteristics of power lines, especially the special characteristics of China's power grid, combining various advanced digital signal processing technologies and making the most of the computing power of the embedded microprocessor, and making efforts in anti-interference. After a large number of computer simulation analyses, a relatively comprehensive optimal implementation scheme was finally determined.
In the subsequent chip design process, its front-end and back-end design capabilities were fully utilized, combined with the chip packaging and manufacturing capabilities of its partners, to complete the design and finalization of the RISE3000 series chips.
Ruiscom Microelectronics has invested significant human and material resources in the implementation and improvement of the communication protocol, ensuring its compatibility with international standard protocols and incorporating routing control layers to meet the specific needs of China's power grid. This allows each communication terminal to not only perform its own communication functions but also provide services to the entire network that would normally require dedicated routing terminals.
In addition to providing users with a transparent network communication channel, Rasco Microelectronics' carrier communication chips also offer hardware resources for various applications, including a user-dedicated embedded microprocessor, serial communication interface, sufficient input/output control ports, and multiple external interrupt signal ports. Using these resources, users can write their own applications, transmit data to a host computer, directly control certain physical switches, or read external status signals, etc.
The RISE3000 series chips are a series of SoCs specifically designed for intelligent control networks. They utilize power lines as a communication medium to connect electrical devices along power lines into a control network. The RISE3000 series is designed to comply with international standards such as EIA- 709.1 , EIA- 709.2 , and EN50065-1. It also incorporates an automatic routing protocol layer and, with its superior physical layer design and robust network communication protocols, ensures reliable network communication performance.
Taking the RISE3501 power line carrier chip as an example (see figure), it integrates a modem module for carrier communication, with a physical layer communication rate of 5.5Kbps . It also features an embedded high-speed 8-bit CPU, 12KB of SRAM, and 64KB of FLASH memory. Furthermore, the device has eight software-configurable GPIO ports, eight configurable multiplexed input/output ports, and three 16-bit timers, and offers programmable BPSK modulation carrier frequency and programmable pulse width modulation (PWM) output.
The image shows the internal functional modules of the RISE3501 power line carrier chip.
With the advancement of urban modernization, the trend towards smart grids is becoming increasingly prominent. Besides smart meters, power line carrier communication technology is being used more and more widely in smart buildings, smart homes, and smart street lighting, playing an increasingly important role.
As always, Ruiscom Microelectronics will further strengthen its cooperation with enterprises and experts from all walks of life, and continue to contribute to the application of power line carrier communication technology in smart meters and the further promotion and popularization of smart meters.
