With his years of experience at major technology companies, few quality and reliability experts are as well-suited to their jobs as Ciaran Fox, vice president of quality and reliability for Enphase Energy. Enphase believes so deeply in continuously raising quality standards that the head of quality assurance and reliability reports directly to the Enphase CEO.
“When we talk about the Enphase cycle of quality, the process starts out in design, goes into testing, goes into manufacturing, and then goes into the field, and this is a cycle or wheel with feedback systems that we’re continuously turning,” says the energetic VP of quality and reliability. “The faster we can turn the wheel, the faster we can continuously improve our products.”
The company’s ability to accumulate hundreds of gigabytes of field data on a weekly basis via its Enlighten monitoring software is directly used to understand field conditions and improve Enphase products. This system of surveillance and remote diagnostics serves many functions including acting as what Fox characterizes as “an in-situ detector of grid fluctuations.” This is an important competitive advantage with respect to quality product monitoring. “Using this system and remote diagnostics, we have developed a library of more than 150,000 grid waveforms that Enphase uses during the product development process to simulate grid fluctuations, identify possible stress points, and make the units more robust.”
“Continuous improvement is fundamental to our quality strategy,” Fox says. “This means learning from the field and building tools that facilitate and automate real-time field feedback.”
“We fundamentally believe that you can’t test in quality, you have to design it in and make it part of every aspect of the business.” Fox says. When Enphase develops products, “it starts with clearly defining product and field requirements that correspond to how the components inside Enphase products are used, and what kind of stress these components experience. All of this is specified in a series of documents that start at the product’s inception, documents that have to be approved by company executives.”
“Enphase’s product development process is similar to what I saw used in large, experienced companies like an IBM,” he says. “Enphase uses a stage-gate product development process and at milestone checkpoints, we take readouts that represent successive levels of increasing quality requirements, culminating in the certification of the product.”
Hardware and software must both be stressed well beyond their specifications. Only by “testing to fail” can the numerous variables that could potentially lead to field failures be discovered and addressed. “We have the mentality of pushing our designs to their breaking points, understanding those breaking points and continuously improving on them. This is about knowing how your product can fail, even if you believe those stress conditions will never actually happen in the field.”
Fox cites a vivid example of Enphase’s enhanced testing that takes robustness to another level. “We submerge the microinverters in water, and operate the units while under thermal cycle stress. It’s a test of water ingress into the unit and what that could cause in the unit during operation. We’re testing for the kind of thing that makes it able to stand up to a hurricane.”
For the shrinking number of microinverters that do come back from the field to the testing labs, Enphase’s failure analysis team works meticulously to diagnose the cause of the possible performance issues, running systems diagnostics and tearing down the units to the component level. Those forensics-based reliability learnings are fed back to the product development group, which can then “take steps to reduce stress on individual components, and where there is stress, add more robustness to that, either by the component’s design or process improvements,” he says.
Enphase’s quality and reliability expertise as well as its impressive suite of customized testing equipment have been recognized by such third-party product compliance testing entities including CSA and VDE. Enphase labs are VDE TDAP (technical data acceptance) certified. This accreditation means that “we can do the testing, share the results, and obtain required certifications,” according to Fox.
The system verification testing capability present at Enphase’s facilities in Petaluma has been largely replicated and deployed at the company’s European campus in Lyon, France. The testing regimens for Europe are more challenging in some ways than the United States, since “there are many different standards, so we have to specifically tailor the units to each country,” he says.
One hundred percent of Enphase microinverter systems are tested during manufacturing. “We not only test all Enphase products during manufacturing, but also conduct ongoing reliability tests at the production site to assure we are meeting our requirements and continuously improving. We do not leave quality and reliability to chance,” Fox says.