Electrification Ramps Up
Seemingly ever-changing, the energy market is now poised to kick into high gear when it comes to embedded electronics. To help system developers keep pace, chip vendors are rolling out advanced solutions for solar, smart metering, vehicle charging and more.
The energy market seems to be in a constant state of transition, with the dual challenges of improving legacy systems and enabling new innovations. In November, market research firm Frost and Sullivan released a report outlining the top growth opportunities in the energy and environmental industries for 2021.
According to the report, the move to a decarbonized electricity system continues to gain pace, with coal plant closures increasing. Meanwhile, renewable energy investments continue to accelerate. Utility-scale investment stays strong, but residential and commercial solar PV systems are forecast to see very strong growth, increasingly in combination with battery energy storage, fundamentally changing the energy system, says the report. It forecasts an average of $340 billion will be invested annually in renewable energy sources over the next decade. Frost and Sullivan also says that global battery energy storage investment will increase by 20% to reach $47 billion by 2030.
Whether it’s inverter circuitry for solar energy or smart metering for new connected-power grid innovations, leading chip vendors from the microcontroller (MCU) and analog IC space are developing new solutions that serve today’s ever-evolving energy infrastructure demands. Over the past couple years, a diverse crop of those IC solutions has emerged, including chips and reference designs aimed at solar energy, smart metering, power grid infrastructure, electric vehicle charging and more.
SIC-BASED SOLAR INVERTER
Exemplifying those trends, Silicon carbide (SiC) technology offers a level of energy efficiency that’s caught the interest of the solar energy market. Along those lines, last summer ON Semiconductor introduced a full SiC power module for solar inverter applications, which was selected by the global provider of power and thermal management solutions, Delta, to support its M70A three-phase PV string inverter portfolio.
The NXH40B120MNQ family of full SiC power modules integrate a 1200V, 40mΩ SiC MOSFET and 1200V, 40A SiC boost diode with dual boost stage (Figure 1). The use of SiC technology delivers the low reverse recovery and fast switching characteristics needed to achieve the high levels of power efficiency required in applications such as solar inverters, says ON Semi.
As part of ON Semi’s portfolio of Power Integrated Modules (PIMs) based on wide bandgap (WBG) technology, the NXH40B120MNQ offers a high level of integration with pin assignment optimized for inverter design. By using SiC components, the power module delivers low conduction and switching losses, enabling the use of higher switching frequencies, which contributes to higher inversion efficiency.
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The modules are designed for ease of use, with solderless press-fit connections and customer-defined thermal interface options, depending on customer preferences. The NXH40B120MNQ full SiC power module is available in 2-channel and 3-channel variants, and is complemented by the NXH80B120MNQ0, a 2-channel module that integrates a 1200V, 80mΩ SiC MOSFET with 1200V, 20A SiC diode.
MOSFET FOR SOLAR INVERTERS
For its part, in November, Fronius International launched its Symo GEN24 Plus solar inverter based on SiC technology from Infineon Technologies (Figure 2). The unit’s Multiflow technology makes it suited for a wide range of applications supporting energy self-sufficiency. It not only powers for direct use in the household, but it also offers an interface for energy storage systems. The hybrid inverter is designed for water heating and the charging of electric cars, and can be connected to external systems.
To maximize the advantages of SiC, engineers from Fronius and Infineon jointly optimized the layout and chip assembly of the modules. Based on Infineon’s Easy module, the inverter’s booster stages use 1200V CoolSiC MOSFETs in combination with CoolSiC diodes. In combination with the high voltage storage from BYD, the Symo GEN24 Plus achieved a record value in the System Performance Index (SPI) of 94% in the 10kW class—the only one in this combo rate Class A energy efficiency.
According to Andreas Luger, Head of R&D Power Electronics from the Solar Energy Business Unit at Fronius, the CoolSiC technology enables a significant increase in switching frequency. Compared to the previous generation, the functionality is significantly improved, while its size remains comparable. Each device now also has an output for a secure power supply, and backup power, in addition to the standard connection options for a hybrid inverter.
SiC technology is also used for the battery stage in the solar inverter. One Easy 1B 1200V from Infineon with an RDS(on) of 45mΩ is used in the bidirectional DC-DC converter. The inverter stage implements a SiC hybrid solution in an Easy 2B module, which has also been tailored to the needs of Fronius. The NPC1 topology combines silicon-based 650V TRENCHSTOP 5 IGBTs and rapid diodes with CoolSiC Schottky diodes. The modules are controlled in all stages with an EiceDriver IC gate driver.
The combination of SiC MOSFET modules in the booster and battery input with hybrid modules in the inverter stage ensures the best possible ratio of efficiency and cost, says Infineon. Because Infineon’s SiC power semiconductors have a high-power density, the Symo GEN24 Plus from Fronius offers many functions such as backup power, storage connection, multi-MPP tracker and energy management. The inverter weighs only 24kg and has a small volume (594mm x 527mm x 180mm). Its active air-cooling can reduce the temperature of the power electronics parts, and thus extend service life. The inverter is available in the power classes 6kW, 8kW and 10kW. Fronius supplies this inverter primarily in Europe, South America and Australia.
dSPIC-BASED MICROINVERTER
For its approach to a solar inverter implementation, Microchip Technology makes use of its dsPIC Digital Signal Controller family of MCUs. The company provides a reference design called “Grid-Connected Solar Microinverter Reference Design” [1]. It demonstrates the flexibility and power of SMPS dsPIC Digital Signal Controllers in grid-connected solar microinverter systems (Figure 3a).
The design has a maximum output power of 215W and ensures maximum power point tracking for PV panel voltages between 20VDC to 45VDC. High efficiency was achieved by implementing a novel interleaved active-clamp flyback topology with Zero Voltage Switching (ZVS), says Microchip. The reference design is implemented using a single dsPIC33F “GS” digital-power DSC from Microchip that provides the full digital control of the power conversion as well as all system management functions (Figure 3b). The design enables you to use the dsPIC33F “GS” DSC to cost effectively develop products using advanced switching techniques and topologies that lower switching losses and improve overall system efficiency.
The dsPIC33F “GS” DSC family of MCUs includes advanced features such as Live Update flash capability, which is especially helpful for high-availability or “always-on” systems. Live Update can be used to change the firmware of an operating power supply, including the active compensator calculation code, while maintaining continuous regulation.
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Other key features of this family include up to five 12-bit ADCs with as many as 22 ADC inputs, providing total throughput of 16 MSPS with a 300ns ADC latency. The dsPIC33EP “GS” devices include 12-bit DACs for each of the four analog comparators for higher-precision designs. The two on-chip programmable gain amplifiers can be used for current sensing and other precision measurements. Including these advanced analog amplifiers on the device reduces the number of external components required, thereby saving cost and board space.
SMART METERING
Collecting electricity metering data remotely over wireless networks is certainly nothing new. But in this era of Smart Metering and IoT technologies, metering has advanced to new levels. Serving those needs, last summer STMicroelectronics (ST) teamed up with Stackforce (an ST Authorized Partner) to deliver a wireless M-Bus (wM-Bus) software stack that leverages the integrated sub-GHz radio and multiple modulation schemes supported by STM32WL MCUs to cut bill-of-materials costs and enhance flexibility for developers of Smart-Metering systems (Figure 4).
Developed by Stackforce, the wM-Bus stack complies with most of EN 13757-3/-7, covering the upper layers of the Wireless M-Bus protocol stack, as well as the lower layers (EN 13757_4) and its wM-Bus modes S, T, and C used throughout Europe in the 868MHz band. The mode N for operation at 169MHz is also an option, too. In addition, it meets several other metering standards, including the most common Open Metering System (OMS) specification, as well as more specific standards like Dutch Smart Meter Requirements (DSMR) or CIG Italian Gas Committee specifications.
Supported by the STM32 development ecosystem, STM32WL MCUs are ultra-low-power devices that use a range of ST technologies and design approaches to meet smart-meter designers’ needs. The sub GHz radio inside STM32WL has a wide linear frequency range, dual power output, and can satisfy EN 300 220, FCC CFR 47 Part 15, ARIB T108, and other radio-equipment regulations, including China regulatory requirements to assist development of products for markets worldwide. Other key features include an integrated switched-mode power supply (SMPS) and hardware cryptographic accelerators.
IC FOR ELECTRICITY METERING
Analog Devices (ADI) offers an electricity metering solution in the form of some specialized chips. This includes its ADE9153B1 device, a highly accurate, single-phase, energy metering IC. The device implements sensor monitoring and self-calibration which the company brands “mSure.” mSure technology allows meter health monitoring and advanced tamper detection (Figure 5). The monitoring feature allows the user to check the overall accuracy of the sensor and signal path to identify accuracy drifts that occur over time on the current and voltage channels, independently.
Similarly, mSure offers advanced tamper detection with the ability to detect unusual changes on the sensors. mSure runs in parallel to the metering measurements, allowing uninterrupted and unaffected metrology in the ADE9153B. Self-calibration with mSure enables a meter to automatically calibrate the current and voltage channels without accurate reference meters or accurate sources when a shunt resistor is used as the current sensor. The self-calibration feature supports Class 1 and Class 2 meters.
The ADE9153B includes three high- performance ADCs, providing an 88dB signal-to-noise ratio (SNR). The ADE9153B offers accurate measurement of line voltage and current, and calculates active, fundamental reactive, and apparent energy, as well as RMS. A wide range of power quality information is included, such as dip and swell detection. Current Channel A is well suited for shunts and has a flexible gain stage providing full-scale input ranges from 62.5mV peak down to 26.04mV peak. Current Channel B has gain stages of 1×, 2× and 4× for use with current transformers (CTs). A high speed, 10MHz, serial peripheral interface (SPI) port allows access to the ADE9153B registers.
DESIGN-IN EXAMPLE
Last year, ADI released a customer design win article “Electricity Meter Accuracy Monitoring Enabled by ADI’s mSure Technology” [2]. The piece describes how ADI worked with Helen Electricity Network (a distribution system operator in Helsinki, Finland) and Aidon (a supplier of smart grid and smart metering technology and services) for a field trial performed using Energy Analytics Studio, an ADI edge-to-cloud meter analytics solution using mSure technology. The system monitors the accuracy of an electricity meter through its deployed life and detects a wide range of tamper types.
In the system, ADI’s mSure was integrated in every new meter in the field, and a cloud-based analytics service that continually monitors and reports measurement accuracy of each meter in situ. The analytics service provides a utility company with visibility into the accuracy of all meters in its meter population to get ahead of meter issues, quickly replace meters that are outside of their allowed accuracy limits, and, if allowed by regulation, reduce and eliminate sample testing. This allows a utility company to take better advantage of the existing advanced metering infrastructure (AMI) network.
The cloud-based analytics service is used in conjunction with purpose-built evaluation devices installed on premise, in series with a primary meter. The evaluation devices shown in Figure 6 embed the ADI ADE9153B energy measurement IC, which includes mSure technology to enable advanced diagnostics. This way, the meter can pass raw diagnostic information to the analytics service, which performs analysis to provide alerts, observe trends and give reports on the health of the meter. In a real deployment, utility companies can deploy meters based on the ADE9153B energy measurement IC and use the analytics service to seamlessly gain the benefits of mSure, says ADI.
LOW-POWER MCU
MCU vendors continue to see opportunities in the energy market. In December, Renesas Electronics expanded its RA4 Series MCUs with the new 32-bit RA4M3 Group of MCUs (Figure 7). The company says the devices are well suited for developing safe and secure IoT edge devices for low-power applications such as metering, industrial, HVAC and other applications.
The RA4M3 MCUs boost operating performance up to 100MHz using the Arm Cortex-M33 core based on Armv8-M architecture. Featuring high-performance, Arm TrustZone technology, Renesas’ Secure Crypto Engine and a suite of new memory enhancements, the RA4M3 Group makes it easy to develop safe and secure IoT edge devices.
According to Renesas, the RA4M3 Group is designed for low-power IoT applications that require a balance of high-performance, strong security and higher memory. The RA4M3 MCUs combine TrustZone technology with Renesas’ enhanced Secure Crypto Engine, enabling customers to realize secure element functionality in a wide variety of IoT designs. The Secure Crypto Engine incorporates multiple symmetric and asymmetric cryptography accelerators, advanced key management, security lifecycle management, power analysis resistance and tamper detection.
The RA4M3 MCUs drive power consumption down to 119µA/MHz in active mode running CoreMark from flash memory and 1.6mA in standby mode with standby wakeup times as fast as 30µs—a critical element for energy applications operating in the field for extended periods. For memory-intense applications, designers can combine Quad-SPI and SD-card interfaces with the MCU’s built-in embedded memory to increase capacity.
The background operation and flash Bank SWAP option is ideal for memory optimized firmware updates running in the background. The increased embedded RAM with parity/ECC also makes the RA4M3 MCUs ideal for safety-critical applications. The RA4M3 MCUs also feature several integrated features to lower BOM costs, including capacitive touch sensing, embedded flash memory densities up to 1MB, and analog, communications and memory peripherals.
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DC-DC BUCK BOOST
Power grid infrastructure systems face some unique design challenges. According to Texas Instruments (TI), it’s a common challenge for engineers to design for low IQ while providing enough output current to send signals between connected smart grid applications and a network via commonly used radio-frequency standards. Such standards include narrowband IoT (NB-IoT), Bluetooth Low Energy and long-range and wireless M-Bus. Engineers are tasked to conserve energy in wirelessly connected applications that run on batteries.
To address that hurdle, in September TI introduced what it claims is the industry’s first DC-DC buck-boost converter to combine programmable input current limit and integrated dynamic voltage scaling to extend battery life by at least 50% (Figure 8). The TPS63900 maintains the industry’s lowest quiescent current (IQ), 75nA, with 92% efficiency at 10µA and delivers up to three times more output current than competing devices, says TI. This is expected to help engineers extend the life span of battery-powered industrial and personal electronics applications.
The TPS63900 integrates dynamic voltage scaling to deliver power while keeping the system at the minimum voltage required to operate efficiently, maximizing battery life and reducing required maintenance for industrial applications. This feature enables design engineers to optimize power architectures for ultra-low-power sensors and wireless connectivity integrated circuits, supporting applications like energy infrastructure systems that can operate for at least 10 years using the primary battery. For example, the buck-boost converter can be paired with TI’s MSP430FR2155 in security sensors or wireless IoT sensors to monitor the vibration of water pumps for predictive maintenance and help drive down costs.
As the industry’s lowest IQ buck-boost converter to integrate a programmable input current limit, the TPS63900 efficiently charges supercapacitors to buffer peak loads, protect battery capacity, and extend system lifetime and performance. Fully charged supercapacitors help buffer the energy required to operate components that require high peak currents, such as those found in motorized smart locks.
The TPS63900 increases the stability of connected applications by reducing up to 50% of the output-voltage ripple caused by load transients. The buck-boost converter’s ultra-fast transient response maintains low IQ while keeping the internal regulation loop active. This capability is particularly beneficial for applications like smart water and gas meters that are always on but need to consume high power in a short amount of time when sharing data. The TPS63900 is available in a 2.5mm × 2.5-mm wafer small outline no-lead (WSON) package.
SUPERFAST CHARGING FOR EVs
The proliferation of electric vehicle (EV) charging stations is yet another growing area of the energy market where embedded technologies are making a difference. Last summer Spain-based power conversion group Ingeteam and Infineon Technologies joined up to create a superfast electric vehicle (EV) charging system (Figure 9a). Rated at 400kW, the converter INGEREV RAPID ST400 from Ingeteam is based on Infineon’s CoolSiC MOSFETs in an EasyDUAL 2B housing (Figure 9b). A single charging point implements eight of Infineon’s FF6MR12W2M1_B11 modules. Depending on the charging capabilities of the respective car, an EV now only needs to stop for a minimum of 10 minutes for an 80% percent battery charge. This is comparable to refueling a conventional car with internal combustion engine.
The design of the INGEREV RAPID ST400 converter has proven to operate successfully at real life conditions. In 2019, the first project integrating this technology was developed, implemented, and commissioned by IBIL, the leading recharge technology services company in Spain, for Repsol, the multi-energy provider and leading Spanish petrol station operator.
Located at Ugaldebieta in the Bay of Biscay region, it was commissioned in October 2019 as a lighthouse project in the field of electro mobility. The facility on the heavily frequented A-8 motorway features four ultra-fast charging points. These units guarantee optimal distribution of the available power between the four vehicles that can be simultaneously connected. According to Infineon, the technology has operated without any major downturns since the start. SiC technology enables high switching speeds with lower switching losses, says the company. This results in shorter charging times and charging stations that are about one-third smaller, since considerably fewer components are required for cooling.
DAQ SYSTEM FOR EVs
The scope of this article is focused on energy infrastructure, and therefore doesn’t cover technologies inside electric vehicles (we discuss automotive technologies as a separate topic). That said, the emerging and growing energy infrastructure for electric vehicles is tightly tied to on-board vehicle technologies. With that in mind, an interesting recent representative example of state-of-the-art battery management is a the MAX171852 announced in February by Maxim Integrated.
The MAX17852 is a 14-channel, high-voltage, ASIL-D data-acquisition (DAQ) system. Designed for integration within electric vehicles, hybrid electric vehicles and other transportation systems, the IC is well suited for smart junction box, 48V and other automotive battery systems, which can see voltages up to 400V and beyond (Figure 10).
OEMs and electric vehicle manufacturers require that all battery systems meet the highest safety requirements set by the ISO26262 guidelines, says Maxim. Through comprehensive diagnostics and a safety-driven architecture, the company designed and manufactured the MAX17852 to enable customers to design their systems to meet the highest ASIL-D standards for voltage, current, temperature and communication.
The IC also offers what Maxim claims is the highest accuracy for delivering voltage, current and temperature data with tight time synchronization. It allows a typical cell voltage measurement of ±0.45mV at room temperature and a maximum of ±2mV error in a temperature range of 5°C to 40°C, enabling car OEMs to get the most mileage range out of their batteries.
With a current sense amplifier capability of ±300mV, and a gain setting up to 256 times and 0.3% current sense gain error, the MAX17852 provides fast, accurate data for calculating power management, state of health and state of charge. The 14-channel battery data acquisition system integrates a current sense amplifier so that current information is acquired at the same time as cell voltage and temperature. The MAX17852 allows both Hall effect sensor and shunt resistors to be used as sensing components. 
RESOURCES
References:
[1] Microchip’s Grid-Connected Solar Microinverter Reference Design https://www.microchip.com/developmenttools/ProductDetails/PartNO/Grid-Connected-Solar-Microinverter
[2] Electricity Meter Accuracy Monitoring Enabled by ADI’s mSure Technology www.analog.com/en/technical-articles/electricity-meter-accuracy-monitor-enabled-by-adis-msure.html
Analog Devices | www.analog.com
Infineon Technologies | www.infineon.com
Maxim Integrated | www.maximintegrated.com
Microchip | www.microchip.com
ON Semiconductor | www.onsemi.com
Renesas Electronics America | www.renesas.com
STMicroelectronics | www.st.com
Texas Instruments | www.ti.com
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • MARCH 2021 #368 – Get a PDF of the issue
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Jeff served as Editor-in-Chief for both LinuxGizmos.com and its sister publication, Circuit Cellar magazine 6/2017—3/2022. In nearly three decades of covering the embedded electronics and computing industry, Jeff has also held senior editorial positions at EE Times, Computer Design, Electronic Design, Embedded Systems Development, and COTS Journal. His knowledge spans a broad range of electronics and computing topics, including CPUs, MCUs, memory, storage, graphics, power supplies, software development, and real-time OSes.
