Smart Grid Market Trends and ON Semiconductor Smart Meter Solutions

Smart grid is built on the basis of integrated, high-speed two-way communication network, aiming to realize the efficient operation of power grid in a reliable, safe, economical, efficient, environmentally friendly and safe way by using advanced sensing and measurement technology, advanced equipment technology, advanced control method and advanced decision support system technology. This article will talk about the smart grid and smart meter market, and introduce the smart grid and smart meter solutions of ON Semiconductor, the leading high-performance and energy-efficient silicon solution supplier for green electronic products.

Rapidly developing smart grid and smart meter market
Driven by the awareness of green energy conservation, smart grid with smart meter as the core has become a key area for countries around the world to compete for development. The development of smart grid can also benefit utilities and users. For example, smart grid can help power agencies reduce operating expenses, reduce electricity theft, optimize operations and respond to user needs immediately. Users also have the opportunity to enjoy more flexible pricing, save costs due to network metering and help achieve home automation. In addition, the development of smart grid also faces other favorable factors, such as deregulation to intensify competition, and various wireless standards (ZigBee, PLC, Wi-Fi, WiMax and cellular mobile communications, etc.) are emerging.

Driven by these favorable factors, the development prospects of smart grid are quite promising. Taking smart meters as an example, it is expected that global shipments will grow from only a few million in 2008 to about 50 million in 2014, with a compound annual growth rate (CAGR) of 48%. From the perspective of technology trends, the future will move towards two-way real-time communication and open platform/modular services. System integration will also be an important future trend, and it is expected that updateable, plug-in hybrid electric vehicles (PHEV) and home automation will be integrated into smart grid systems. Smart meters will also move towards the adoption of advanced metering systems (AMI) and become part of the future home area network (HAN).

ON Semiconductor's smart meter solution based on AMIS-49587 and NCS5650
The medium and low voltage AC distribution lines used for power transmission can also be used as the transmission medium for data communication. Power line carrier (PLC) communication technology is a technology that transmits analog or digital signals at high speed on distribution lines by carrier. There is no need to rewire the existing power distribution network for communication, and the signal will not be attenuated and shielded by passing through the walls of buildings, which is more cost-effective. This makes this technology popular in many fields such as automatic meter reading systems and lighting control.

ON Semiconductor has developed a spread spectrum frequency shift keying (S-FSK) PLC modem (Modem) for low/medium voltage power line data communication - AMIS-49587. It is a highly integrated, low-power PLC solution that complies with the IEC61334 standard and is suitable for automatic meter reading and management of smart grids, street lighting control, smart power plugs, and building automation. This is the second generation of PLC modem products developed by ON Semiconductor after the early AMIS-30585. Its core is a 32-bit ARM processor, which completes the processing of the physical layer and MAC layer, runs the S-FSK modulation and demodulation algorithm, and also manages the communication with the external MCU. The device contains all analog and digital parts such as S-FSK signal processing and MCU interface management. AMIS-49587 supports the Advanced Metering System (AMI) for two-way communication between utilities and meters, and supports remote meter reading, disconnection of switches and load control. Currently, only about 8% of the 2.65 billion meters in the world are automated meters, so the application prospects of modem chips such as AMIS-49587 that support smart meter applications are very broad.

AMIS-49587 is a narrowband PLC transceiver using S-FSK modulation and precise filtering, which can achieve robust low data rate communication over long-distance power lines and 2,400 bps half-duplex adjustable rate communication. The low operating frequency of less than 20 kHz and the automatic repeater function make communication more reliable and the communication error is lower than that of existing solutions. This device is currently the only device that has been successfully applied in industrial fields for more than 8 years.

AMIS-49587 uses ON Semiconductor's mixed signal technology to integrate analog modem front-end and digital post-processing functions in one integrated circuit. Its most prominent feature is that as a PLC transceiver, in addition to completing the transmission and reception, modulation and demodulation of physical layer S-FSK signals, it also includes the processing of the media access controller (MAC) sublayer, so that designers do not need to involve the details of PHY and MAC protocol transmission, and focus more on the development of the application layer. Most competing solutions require complex embedded software to perform the same functions as AMIS-49587.

Through the exchange of logical link layer (LLC Layer) data packets by AMIS-49587, the underlying frame header, frame check, etc. will be automatically added. This greatly reduces the customer's software development workload, simplifies the design, reduces the development and application costs, and accelerates the listing process. These advantages make AMIS-49587 a core PLC communication device that fully meets the technical requirements of smart grids.

In addition, ON Semiconductor has also launched a highly efficient Class A/B low-distortion line driver, the NCS5650, for smart meter PLC line drive applications. The power supply voltage (VCC) of this device is single-ended 6 to 12 V or dual-balanced ±3.0 to 6.0 V. The design of the NCS5650 has been optimized to receive signals transmitted by the PLC modem, and the output stage is designed to drive up to 2 A of current, coupled to the AC main power supply through an isolation transformer or a simple coil.

The NCS5650 meets the application requirements of PLC line drivers and provides important application advantages. For example, this device is optimized for the A, B, C and D frequency bands of the European Committee for Electrotechnical Standardization (CENELEC) for smart meters, complies with the EN-50065 specification, and can be used for direct coupling or 1:1, 2:1 transformer ratio coupling. The unique 2 A drive capability of the NCS5650 ensures effective communication even at very low power line impedance.

NCS5650 also has advantages in electrical performance. The two-stage operational amplifier can achieve a full power bandwidth of 700 kHz, and the harmonic distortion is also very low, only 0.015% @ 1 kHz. The power consumption of this device is also very low, the rail-to-rail voltage difference is only 0.5 V, the quiescent current is only 20 mA, and the current in shutdown mode is only 150 ?A.

Figure 1 is a block diagram of the PLC solution using AMIS-49587. The solution mainly consists of PLC Modem, AMIS-49587, driver amplifier NCS5650 and coupling transformer.

The red arrow in the figure is the transmission path of the PLC signal. The S-FSK signal modulated by AMIS-49587 is amplified by NCS5650 and coupled to the power line through a transformer. The transformer realizes voltage conversion and impedance matching, and can also be used to isolate strong and weak electricity. In addition to signal power amplification, the two-stage op amp structure of NCS5650 also forms a 4th-order low-pass filter with a very steep attenuation characteristic. In Europe, where there are strict restrictions on power line access equipment, only by adding similar filters can the system ensure that the high-frequency interference injection into the power line meets the requirements of the EN 50065 specification.

The blue arrow indicates the receiving path. The signal coupled from the power line by the transformer is FSK demodulated and analyzed by the internal ARM through the low-pass filter formed by the built-in amplifier of AMIS-49587. The black arrow in the figure is the 50 Hz zero-crossing detection signal pin. The system relies on this signal for synchronization timing. The blue dotted line in the figure is the application processor in the meter, which is responsible for application layer processing communication and metering.

The power supply of this solution is very simple: a 12V power supply is used to power the line amplifier to drive the PLC signal coupling transformer; a 3.3V power supply is used to power the AMIS-49587.

ON Semiconductor's complete solution for smart meters
ON Semiconductor's solution for smart meters includes a series of standard products, application-specific standard products (ASSP) and application-specific integrated circuits (ASIC), which can provide the four basic functions of smart meters, including: power/power management, metering, storage and communication. Specific products include power factor controllers, AC-DC controllers, DC-DC controllers, regulators, MOSFETs, rectifiers, triacs, PLC modems, line drivers and signal amplifiers, filtering, input/output (I/O) and data protection, LCD backlight drivers, EEPROM memory, and smart card interfaces. Figure 2 shows a smart meter application composed of various devices (green parts in the figure) from ON Semiconductor.

As shown in Figure 2, there are many ON Semiconductor products that constitute smart meter applications. In addition to the above-mentioned AMIS-49587 PLC modem and NCS5650 PLC line driver, they also include: input/output protection (data filters for electromagnetic interference (EMI) and radio frequency interference (RFI) filtering, ESD protection diodes and arrays, voltage monitors for current and voltage management), input/output interfaces (data filters, PLL clock generators), smart card and SIM card interfaces, I/O expanders, voltage protection devices (diodes and rectifiers, transient voltage suppressors), operational amplifiers and comparators, power amplifiers, power line modems, EEPROM and SRAM memories, LCD backlight drivers and image/ambient light sensors, input bridge rectifiers, voltage regulator switches (AC-DC controllers and regulators), output rectification/synchronous rectification (Schottky diodes and rectifiers), linear voltage regulator switches (voltage references, display drivers, controllers, linear regulators, converters, charge pumps), etc.

Among them, the data filter NUF2042XV6 for input/output protection is a single-chip device developed for applications that require line termination, EMI filtering and ESD protection. Its bidirectional EMI can prevent noise from entering/exiting the system and save component costs. The transient voltage suppressor (TVS) P6KE6 series for voltage protection can prevent voltage-sensitive components from being affected by high voltage and high energy transients. It has good clamping ability, high surge capability, low impedance Zener and fast response time. NOA1302 is a wide dynamic range ambient light sensor (ALS) with integrated 16-bit ADC and 2-wire I2C digital interface. It uses programmable integrated optimization of noise performance and can provide linear response from nearly 0 lux to more than 100,000 lux. The sensor uses ON Semiconductor's proprietary CMOS image sensing technology to provide low noise and high dynamic range output signals and light response similar to human eye response.

Summary
When developing smart grids and smart meters, designers need to choose the right solution. ON Semiconductor provides a variety of solutions for smart grid and smart meter applications that meet various standards and customer specifications, with many advantages such as simplified design, reduced cost, reduced power consumption, reliable communication and faster time to market.