Module-Level Power Electronics Platforms
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The International Association for Fire Fighters introduced language to NEC 2017 that seeks to...
Seven years have elapsed since Enphase Energy released its first-generation microinverter system, a...
Contemporary microinverter systems were introduced in 2008. Six years later, the potential benefits...
The development and deployment of module-level power electronics (MLPE) dates back to the introduction of products such as Ascension Technology’s 300 W SunSine microinverter and Netherlands-based NKF Electronics’ OK4 inverter line in the late 1990s. Enphase modernized the microinverter platform with the release of its M-175 model in 2008, and also created one of the first system-level MLPE solutions with array aggregation cabling products and its Enphase Enlighten web-based data acquisition and monitoring system. It was the first time that a mainstream PV solution allowed users to easily view and analyze system performance at the module level, and it was an eye-opening experience for solar installers and their customers.
In the decade that has elapsed since Enphase introduced its first-generation microinverter system, the MLPE landscape has slowly been moving toward a higher level of not only product integration but also MLPE-related business partnerships and acquisitions. Examples include SunPower’s 2014 acquisition of microinverter manufacturer SolarBridge Technologies, SMA’s 2016 acquisition of a 27% stake in dc optimizer vendor Tigo Energy, and the 2017 partnership between Enphase and LG to develop an ac module product. In comparison, SolarEdge Technologies built its product portfolio, which includes dc power optimizers that couple with its string inverters, from the ground up with a core focus on leveraging the benefits of MLPE.
While both technical advancements and business acquisitions and partnerships have been reshaping the evolving MLPE landscape, many industry stakeholders contend that regulatory directives, such as NEC 2017 Section 690.12, “Rapid Shutdown of PV Systems on Buildings,” have provided MLPE vendors with a huge competitive boost in the US solar market. This article provides company and product information for eight companies that are active in the MLPE ecosystem in the US and beyond.
In 2009, Dr. Zhi-Min Ling and Dr. Yuhao Luo founded microinverter systems vendor APsystems in California. It is currently headquartered in Seattle. Ling did postdoctoral work at the University of California, Berkeley, and Luo holds a PhD in electrical engineering from the University of California, Los Angeles. Ling and Luo were colleagues at Solaria prior to founding Altenergy Power, which rebranded as APsystems in 2015. APsystems currently has a global footprint with offices in Australia, China, Europe, Mexico and the US.
APsystem’s flagship product, the YC500A microinverter, integrates with two modules and can interconnect with 240 Vac and 208 Vac services. At 240 Vac, it supports a maximum of seven microinverters (14 modules) per 2-pole 20 A branch circuit. With a peak ac power rating of 500 W, the YC500A can accommodate PV modules up to 365 W, but, per the manufacturer, is ideally suited for modules from 280 W to 310 W. The YC500A uses a daisy-chain ac output aggregation approach and power line communication (PLC) between the inverters and the system’s energy communication unit gateway. APsystems also offers a slightly higher-power dual-MPPT YC500i microinverter model with an ac output rating of 548 W. The YC500i features an integrated ground and a trunk cable ac aggregation architecture. It supports ac branch circuits of six microinverters (12 modules) per 2-pole 20 A branch circuit. Both the YC500 series inverters have a maximum input voltage of 55 Vdc and an MPP tracking range of 22 V–45 V.
In 2014, APsystems announced the availability of its 3-phase YC1000-3 microinverter. The YC1000-3 accommodates three modules up to 365 W each or four modules up to 310 W each. Two YC1000-3 models are available that are configured for 3-phase 277/480 V and 120/208 V services. Both models have a 900 Wac continuous power rating and provide phase-balanced and phase-monitored 3-phase ac output. On the dc side, the YC1000 models have a maximum input-voltage rating of 60 Vdc and a MPP tracking range of 16 V–55 V. The YC1000-3 microinverter system uses Zigbee wireless communication and includes an integrated ground.
At Solar Power International in Las Vegas this September, APsystems launched its next-generation YC600 dual-module utility-interactive microinverter. The recently launched microinverter meets the latest grid compliance standards, including UL 1741 SA requirements for California Rule 21. Developed for integration with 60-cell and 72-cell PV modules, the YC600 has a maximum continuous power rating of 548 W and a peak power output of 600 W. It has a maximum input voltage of 55 Vdc and an MPP tracking range of 22 V–45 V. With an ac trunk cable architecture, the system supports ac branch circuits of seven microinverters (14 modules) at 240 Vac and six microinverters (12 modules) at 208 Vac. APsystem’s YC600 microinverter meets NEC 2014 and 2017 Section 690.12 rapid-shutdown requirements. It features Zigbee wireless communication over a mesh network and free system monitoring using APsystem’s ArrayApp software. To simplify installation, the platform Energy Communication Unit offers wireless connectivity to the site’s internet network. APsystems offers 10- and 25-year warranty options on its microinverters.
APsystems / Seattle, WA / 844.666.7035 / usa.apsystems.com
Alexandre Kral and Dr. Christopher Jones founded privately held Chilicon Power in 2010. Both Kral and Jones have degrees in electrical engineering from the University of California, Los Angeles. One unique aspect of Chilicon Power’s business is that the company’s microinverter and gateway products are not only designed but also manufactured in California.
Chilicon Power’s current microinverter is its CP-250E model, which is Rule 21 compliant and can provide reactive power on demand. To provide compatibility with both 60- and 72-cell PV modules, the CP-250E has a wide input-voltage range of 22 V–33.5 V and a maximum input-voltage rating of 60 Vdc. The CP-250E ships from the factory with a maximum continuous output-power level of 250 W, which supports 13-module branch circuits at 208 Vac or 15-module circuits at 240 Vac. Alternately, installers can use the CP-100 gateway to extend the maximum continuous output-power rating to 285 W; in this extended-power mode, the product supports 11-module branch circuits at 208 Vac or 13-module circuits at 240 Vac.
The CP-100 gateway features a 7-inch 800-by-480-pixel LCD touch screen. It uses PLC to interface with the system’s microinverters and also offers Wi-Fi, Ethernet and Z-Wave connectivity. The Z-Wave wireless home automation mesh network protocol enables the gateway to interface with smart home security and energy monitoring devices from vendors such as Aeon Labs. The CP-100 can also provide consumption monitoring and supports zero net export and self-supply modes with the installation of current transformers in the site’s ac panel. The gateway can be cloud interconnected or can operate as a stand-alone unit where connectivity is not available.
Chilicon Power’s microinverter system is compatible with storage inverters from vendors including OutBack Power, Magnum Energy and Schneider Electric in ac-coupled configurations. The CP-250E microinverter carries a standard 25-year warranty.
Chilicon Power / Los Angeles, CA / 310.579.2449 / chiliconpower.com
Founded in May 1997, Darfon Electronics has a design and manufacturing focus that includes a wide range of product groups such as human interface devices, power and energy devices, and integrated components. For example, Darfon is currently the world’s number one notebook keyboard manufacturer. The company has a worldwide footprint that includes its global headquarters in Taiwan, as well as facilities in China, the Czech Republic and South Korea. Darfon’s US subsidiary, Darfon America, is located in Mountain View, California. Darfon Electronics is one of 16 independently operated companies in the BenQ Group and is traded on the Taiwan Stock Exchange.
Darfon’s current microinverter lineup includes two models, the MIG300 and the G320. The MIG300 has a continuous ac output-power rating of 250 W and a peak ac output rating of 260 W. It has a maximum input voltage of 60 Vdc and an MPP tracking range of 24 V–40 V. A trunk cable aggregates up to 16 microinverters per 20 A single-phase ac branch circuit and 24 microinverters per 30 A ac branch circuit. In 2015, Darfon partnered with PV mounting solutions provider IronRidge to develop the ACRak 300. The ACRak combines Darfon’s MIG300 microinverter with IronRidge’s XR100 XR Rails. To reduce installation time and improve overall installation quality assurance, the ACRak features factory-assembled sections of rail, microinverters and cabling.
Launched at Solar Power International 2016, Darfon’s third-generation microinverter, the G320, is compatible with 60- and 72-cell modules with STC power ratings of up to 350 W. The microinverter platform has multiple phase configurations and is available in four voltage options that are set at the factory (208 V, 220 V, 240 V and 277 V), making it suitable for deployment in residential, commercial and industrial applications. The G320 has a maximum input voltage of 60 Vdc, an operating voltage range of 22 Vdc–60 Vdc and an MPPT range of 24 Vdc–45 Vdc. Its continuous power rating is 300 W. Crews can install a maximum of 19 G320s on a 30 A branch circuit in 240 Vac systems and up to 66 (balanced) units on a 30 A 277 Vac circuit. The platform features flexible cabling configurations with or without trunk cabling.
Darfon’s microinverters carry a 25-year warranty. Its microinverter platform includes a cloud-based monitoring system. Darfon also offers a lineup of combiner boxes for branch circuit aggregation.
Darfon America / Mountain View, CA / 650.316.6300 / darfonsolar.com
Raghu Belur and former Cisco colleague Martin Fornage launched Enphase Energy in 2006 with the vision of creating not only a modern microinverter system that pushed power conversion and optimization into the array at the module level, but also a platform that enabled what was at the time an unprecedented level of system monitoring granularity. Both Belur and Fornage are still actively involved at Enphase, serving in the roles of vice president of products and strategic initiatives and chief technology officer, respectively. Enphase completed its IPO in 2012 and trades on the NASDAQ exchange with stock symbol ENPH. While Enphase has faced challenges in terms of its share price and profitability, it has clearly had the biggest impact of any microinverter system company on the development and advancement of the product class.
In early 2017, Enphase Energy began shipping its next-generation integrated solar, storage and energy management offering, the Enphase Home Energy Solution with IQ. The system features the company’s sixth-generation Enphase IQ Microinverter. The Enphase IQ 6+ Micro supports 60- and 72-cell modules up to 400 Wdc, and the Enphase IQ 6 Micro is compatible with modules up to 330 Wdc. The IQ 6+ model has a maximum input voltage of 62 Vdc and an MPP tracking range of 27 V–45 V. The IQ 6 model has a maximum input voltage of 48 Vdc and an MPP tracking range of 27 V–37 V. At 240 Vac the IQ 6 supports 20 A ac branch circuits of 16 modules, and the IQ 6+ supports 20 A ac branch circuits of 13 modules. The new microinverter design includes a double-insulated noncorroding polymeric enclosure. Enphase IQ 6 microinverters comply with fixed power factor, voltage and frequency ride-through requirements, and meet requirements for distributed solar on utility networks, including Rule 21 in California and Hawaiian Electric Company Rule 14H. Enphase IQ microinverters carry a warranty of 25 years. The C250 model, developed for 480 V 3-phase systems with 72-cell modules, rounds out Enphase’s microinverter lineup.
From the start, Enphase has had a system-level engineering approach. In February 2017, it added an energy storage component to its system with the availability of its AC Battery in the US. The AC Battery, a scalable modular energy storage system, is a component of Enphase’s Home Energy System, which includes the company’s IQ microinverters, Envoy networking hub and gateway, and module-level Enlighten monitoring software. The Enphase AC Battery uses lithium iron phosphate chemistry from Eliiy Power. The cells provide 1.2 kWh of capacity at a nominal voltage of 25.6 Vdc. The AC Battery can discharge to 100% of rated capacity and has a round-trip cell efficiency specification of 96%. Weighing only 55 pounds, the AC Battery is designed for single-person installation and interconnection with standard household wiring. Its enclosure is NEMA 2 rated for indoor installation in an unoccupied space. The AC Battery carries a 10-year or 7,300-cycle warranty for greater than 80% of its initial rated capacity.
In addition to offering integrated energy storage solutions, Enphase will add new ac module products in 2017, including some produced in partnerships with LG and Jinko Solar. Premiered in July at Intersolar North America in San Francisco, LG’s 60-cell 330 Wdc NeON 2 ACe model integrates Enphase’s IQ 6+ microinverter for ac module applications. This version, built on the IQ microinverter, includes an inverter-to-module mounting bracket that ships in a collapsed position, permitting optimal shipping density. Once on the rooftop, installers lift up the microinverter to connect the trunk cable, which elevates the microinverter off the back of the module by 15 mm to allow sufficient airflow for cooling. LG’s NeON 2 ACe ac module has a continuous ac power rating of 280 W.
Enphase Energy / Petaluma, CA / 877.797.4743 / enphase.com
Magnum Energy, founded in 2006, designs and manufactures inverter-chargers for mobile, marine, off-grid and backup power applications, as well as producing PV charge controllers, component integration panels and system monitoring equipment. In 2014, Sensata Technologies acquired Magnum Energy. Headquartered in Attleboro, Massachusetts, and founded in 1916, today Sensata Technologies is a global provider of sensing, electrical protection, control and power management solutions with operations and business centers in 13 countries.
In 2016, Magnum announced the launch of its MicroGT 500 microinverter. Designed for integration with the company’s battery-based inverter-charger systems, as well as for use in grid-direct power export applications, the MicroGT 500 communicates with Magnum Energy battery-based inverters in ac-coupled mode to taper the charge based on temperature-compensated battery state-of-charge parameters.
Each dual-MPPT MicroGT 500 microinverter supports two PV modules. For the dc side, Magnum recommends a module STC power range of 180 W–310 W, but the inverter can accommodate modules of up to 365 W. The microinverter has a maximum input voltage of 55 Vdc and an MPP tracking range of 22 V–45 V. Its rated ac power output is 500 W. Each 20 A breaker supports ac branch circuits of up to seven microinverters (14 modules). The MicroGT 500 is NEC 690.12 compliant.
Magnum was the first manufacturer in the US to offer inverter-charger models with split-phase 120/240 Vac output. Its 24 Vdc and 48 Vdc nominal MS-PAE series inverter-chargers connect to the grid for ac battery charging, but do not export power to the utility grid without the integration of an ac-coupled string or microinverter system, such as its MicroGT 500 microinverter. Magnum Energy’s MagWeb GT communication unit provides an integrated dashboard of the MicroGT output and MS-PAE Inverter/Charger output, including the battery state of charge.
Magnum Energy / Everett, WA / 425.353.8833 / magnum-dimensions.com
Founded in 2006, SolarEdge Technologies offers an end-to-end power electronics solution for distributed power projects. Its system includes module-level power optimizers, module-level monitoring, single- and 3-phase string inverters, and a dual-port inverter for energy storage systems. Guy Sella, currently serving as CEO, and Lior Handelsman, vice president of marketing and product strategy, founded the company. SolarEdge began commercial shipments of its first-generation string inverter, module-level dc optimizer and monitoring systems in 2010. The company’s global headquarters are in Herzliya, Israel, and its US division is headquartered in Fremont, California. SolarEdge completed its IPO in 2015 and trades on the NASDAQ exchange with stock symbol SEDG.
SolarEdge offers both module-integrated and module–add-on power optimizers. Its P-Series optimizer is designed to integrate with a single module. The product lineup has five models. The P300 and P320 optimizers are compatible with 60-cell modules and have a maximum input voltage of 48 Vdc and an MPP tracking range of 8 V–48 V. With a maximum input voltage of 60 Vdc, the P370 optimizer is compatible with higher-power 60- and 72-cell modules. Developed for 72- and 96-cell modules, the P400 optimizer has a maximum input voltage of 80 Vdc and an MPP tracking range of 8 V– 80 V. Rounding out the series, the P405 optimizer is compatible with the high-voltage and low-current characteristics of thin-film modules. It has a maximum input voltage of 125 Vdc and an MPP tracking range of 12.5 V–105 V. SolarEdge also offers a five-model P-Series Commercial optimizer lineup. The company designed the higher-power P-Series Commercial products for use with two PV modules connected in either series or parallel. All P-Series optimizers are rated for 1,000 V applications, carry a 25-year warranty and are designed specifically for integration with SolarEdge inverters.
SolarEdge’s inverter portfolio includes both single- and 3-phase models, as well as a dual-port inverter for projects that require energy storage. In 2017, SolarEdge began shipping a new line of single-phase inverters with its HD-Wave architecture. The inverter topology allows for high-power conversion efficiencies with a small form factor that is also extremely lightweight. The highest-capacity HD-Wave model, the 7.6 kWac SE7600H-US with disconnect switch, measures 17.7 by 14.6 by 6.8 inches (height by width by depth) and weighs only 26.2 pounds.
In September, SolarEdge and LG announced a partnership targeting the high-end residential and commercial PV rooftop markets in North America. The package combines LG’s high-efficiency NeON modules with SolarEdge’s string inverters and P370 and P800 power optimizers for residential and commercial installations, respectively. It also includes free module-level monitoring. The residential ac module is compatible with SolarEdge’s HD-Wave and StorEdge inverters, as well as its recently launched inverter-integrated electric vehicle chargers.
SolarEdge Technologies / Fremont, CA / 510.498.3200 / solaredge.com
Headquartered in San Jose, California, SunPower has achieved an impressive level of not only component but also business integration with its SunPower Equinox system for residential applications. All of the system’s components—module, microinverter, racking and monitoring—are SunPower products and come with 25-year product and production warranties.
As a business entity, SunPower dates back to 1985, when its co-founder, Dr. Richard Swanson, a professor of electrical engineering at Stanford University, earned grants from the Electric Power Research Institute and the US Department of Energy to support his research into cost-effective PV cell designs. Additional investments by two venture capital firms led to the incorporation of SunPower in the same year. SunPower held an IPO in 2005 and trades as SPWR on the NASDAQ exchange. In 2011, Total, a French multinational oil and gas company, purchased a 60% stake in the company. In 2014, SunPower acquired Austin, Texas–based microinverter designer and manufacturer SolarBridge Technologies, paving the way for its ac module platform.
The SunPower Equinox system includes SunPower ac modules and factory-installed microinverter, a low-profile InvisiMount rail-based racking and mounting system, and an EnergyLink monitoring platform. SunPower’s 96-cell SPR-X22-360-C-AC ac module has a nominal STC rating of 360 W with a +5/-0 power tolerance. Its average module conversion efficiency value is 22.2%. On the ac side, the SPR-X22-360-C-AC module has a maximum continuous power rating of 320 W. It supports single-phase 20 A branch circuits of up to 12 ac modules.
SunPower / San Jose, CA / 800.786.7693 / sunpower.com
Headquartered in Los Gatos, California, privately held Tigo Energy was founded in 2007. Tigo was one of the first developers of dc optimizer platforms for PV systems and has ramped up its product innovation and release in recent years. The US Department of Energy awarded Tigo $3.5 million in 2012 as part of the SunShot Initiative incubator program. In 2016, SMA Solar Technology acquired a 27% stake in Tigo, opening the door for the development of dc-optimized SMA inverter designs.
Tigo developed its TS4 universal platform for both factory-integrated module applications, where the TS4 platform replaces the standard module junction box, and for retrofit applications, where installers deploy add-on units in the field. The TS4 system base provides a single plug-and-play interface for electronic covers that offer a range of functions: diodes that provide bypass functionality similar to that of conventional modules, except that the diodes are field replaceable; diodes plus monitoring; diodes with monitoring and safety, including NEC 690.12 rapid-shutdown compliance, module-level deactivation, automatic or manual shutdown, and overvoltage and overtemperature protection; diodes with monitoring, safety and module-level optimization; and finally, diodes with monitoring, safety, optimization and longer, higher-voltage string configurations. The TS4 platform is CSA listed to UL 1741. This year Tigo Energy has extended its modular TS4 platform design to support 1,500 Vdc PV systems.
In addition to partnering with SMA, Tigo has built relationships with inverter manufacturers thanks to the push to develop systems that meet NEC 2017 rapid-shutdown requirements. This cooperation has allowed companies including ABB, Fronius USA, Ginlong Solis, Kaco new energy, Sungrow USA and Yaskawa–Solectria Solar to certify that their inverter products meet rapid-shutdown requirements when used in conjunction with Tigo’s TS4 safety product.
In the fall of 2017, Tigo announced two new products. Its TS4 Duo add-on or retrofit product supports two PV modules connected in series with a combined power of up to 700 W and a combined voltage of up to 90 Vdc. Tigo offers three covers for the Duo product, including TS4-R-O-Duo (optimization), TS4-R-S-Duo (safety), and TS4-R-M-Duo (monitoring). Both the TS4-R-O-Duo and TS4-R-S-Duo are NEC 690.12 rapid-shutdown compliant and were pending UL approval at the time of publication. Additionally, Tigo released its new SMART App, which enables installers to design, configure, register commission of and monitor customers’ PV systems from the field via a mobile phone.
Tigo’s TS4 solution is available as a factory-integrated J box solution from module manufacturers including ET Solar, Jinko Solar, Sunpreme and Trina Solar. Tigo backs its TS4 products with a 25-year warranty.
Tigo Energy / Los Gatos, CA / 408.402.0802 / tigoenergy.com
Joe Schwartz / SolarPro / Ashland, OR / solarprofessional.com