Module-Level Power Electronics Platforms

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 /


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