Enphase Converts 13.8 kV to 800 VDC With 132 Modules in Its First IQ SST Test, With 34.5 kV Next and Pilots in 2027

Power Electronics Product Solid State Transformers
Marin Holt
October 29, 2026
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8 minutes read

Conversion: 13.8 kV AC to 800 VDC
Test system: 132 power modules, 44 in series per phase
Module rating: 5.5 kW each, GaN switching
Next steps: 34.5 kV test, megawatt-scale racks by end of 2026, pilots in 2027
Q3 revenue: $293.3 million

Enphase Energy said on October 27 that its IQ Solid-State Transformer converted 13.8 kV AC to 800 VDC at its research and development lab in Austin, Texas. The test system used 132 power modules. Each phase carried 44 modules in series, and the three phases ran as one system. Enphase said the output stayed at a stable 800 VDC through load steps that simulated the fast-changing demands of AI compute racks. The Fremont, California company plans to extend the test to 34.5 kV in the coming weeks. It plans megawatt-scale racks at rated power before the end of 2026 and customer pilots in 2027.

Each power module handled only a few hundred volts, so no single module saw the full 13.8 kV. Each 5.5 kW-rated module combines gallium nitride switching, the fifth-generation Kestrel ASIC and a high-frequency transformer that Enphase designed in house. The company already builds the first IQ SST modules at its plant in Arlington, Texas. Enphase said the design keeps running if one module fails.

What the Test Showed

“The system performed exactly as designed,” said Hans van Antwerpen, chief technology officer at Enphase Energy. “All 132 modules shared the voltage evenly, and the 800 V output held steady through every load step. The architecture scales by adding power modules in series, so 13.8 kV gives us a clear path to 34.5 kV.” Raghu Belur, co-founder and chief product officer, tied the design to the nearly 90 million microinverters the company has shipped.

The demonstration came one day after Enphase and Infineon announced 900 V gallium nitride monolithic bidirectional switches for the same power modules. The two companies already paired on 650 V GaN devices for the Enphase IQ9 microinverters. Enphase has tested the 900 V parts and is now integrating them into IQ SST development, Semiconductor Today reported. Production qualification comes next. “Moving to 900V gives us more voltage headroom while retaining the benefits of high-frequency switching,” van Antwerpen said in that announcement. “It allows us to remove converter stages from the system and reduce the number of components in the power path.”

The Business Behind It

Enphase reported the same day that third-quarter revenue was $293.3 million. GAAP net income was $23.4 million, and cash and marketable securities stood at $931.8 million. The company shipped 1.42 million IQ microinverters, or 655.2 megawatts DC, and 129.9 MWh of IQ batteries. Enphase said it is developing IQ SST for two global technology leaders. Its IQ SST customer and partner pipeline more than doubled in the quarter to over 50. The company expects commercial shipments to start in 2028.

Other solid-state transformer work runs at similar voltages. In August, the New York Power Authority and the Electric Power Research Institute tested a one-megawatt solid-state transformer under realistic utility conditions at an EPRI test site, MIT Technology Review reported. North Carolina State University professor Srdjan Lukic built that prototype in his lab. The prototype was roughly 98% efficient, Lukic said, while an equivalent conventional transformer and rectifier would be about 96% efficient together. The prototype operates at about 15,000 volts. Heron Power raised $140 million in February to commercialize its own solid-state transformer.

Why It Matters

Converting medium-voltage AC straight to 800 VDC removes conversion stages between the utility feed and the rack. For a data center operator, the test is the first public evidence that the Enphase series-module design holds its output under rack-style load steps at a real distribution voltage. Two numbers matter next: the 34.5 kV run and the megawatt-scale rack test. Enphase promised both before the end of 2026.

For buyers, the gap between a lab test and a product is still two years. Pilots start in 2027 and shipments in 2028. Today the revenue remains a microinverter and battery business. Infineon has tested the new switch but has not qualified it for production, so the module in the 2028 product is not the module in this test.

Critical Perspective

The 13.8 kV test proves voltage sharing across 132 modules at a few hundred volts each, but Enphase disclosed no efficiency figure, no rated power for the full stack and no duration for the load steps. The 5.5 kW module in this test does not yet carry the 900 V Infineon switch, which is tested but not qualified for production, so the hardware that ships in 2028 will differ from the hardware that passed here. The pipeline of over 50 is a count of names rather than signed orders, and the $293.3 million quarter still comes from microinverters and batteries. Until the 34.5 kV run and the megawatt-scale rack test land before year end, what is the evidence that the series architecture holds 800 VDC at rated power rather than in a lab load step?