Principal Engineer, Power Density

Job Description

The Enphase Energy SST Product Innovation Team sits in the Office of the CTO and is responsible for defining, prototyping, and scaling the next generation of Enphase storage and power systems. We are a fast-moving, multi-disciplinary group on a mission to push the boundaries of energy density, reliability, and system efficiency.

This is a hands-on leadership role. You will attack every loss mechanism - conduction, switching, magnetic, capacitive, and thermal - and systematically eliminate them through technology innovation, topology optimization, and cross-functional integration. You will work side-by-side with mechanical and thermal engineers to translate efficiency gains into cooling reduction and footprint compression. If you have deep expertise in power inverters, know where every watt is lost, and know how to make the product smaller and more efficient - this role was built for you.

What You Will Do

• Lead the power density rapid increase roadmap: Own the strategic and execution roadmap to rapidly increase power density. Define the target metrics (W/in??, W/in2, W/kg, efficiency vs. cooling), break down the improvement into loss-reduction initiatives, and drive cross-functional execution to hit the milestones.
• Identify the easiest approach to solve power density packaging problems: Quickly assess complex power density and packaging challenges and identify the simplest, highest-impact solution. Distinguish between problems that require fundamental topology changes versus those solvable through packaging, cooling, or component selection. Guide the team to prioritize the path of least resistance that delivers the greatest density improvement.
• Map and attack all power conversion loss mechanisms: Develop a comprehensive loss budget for the SST system: conduction losses, switching losses, magnetic losses, capacitive losses, and control overhead. Prioritize loss mechanisms by impact and attack them systematically.
• Integrate with mechanical and thermal teams for footprint reduction: Translate every efficiency gain into cooling system optimization. Collaborate with thermal engineers to reduce thermal resistance, lower coolant flow requirements, and eliminate heat sink mass. Work with mechanical engineers on compact packaging, integrated cooling channels, and structural optimization. Push the boundary where efficiency gains directly shrink the skid.
• Define and enforce loss budgets: Establish component-level and system-level loss budgets. Allocate loss targets to each subsystem (inverter stage, transformer, filter, auxiliary) and enforce them through design reviews and validation testing.
• Benchmark and track industry trends: Monitor state-of-the-art in industry. Identify technology gaps and opportunities. Ensure Enphase maintains or extends leadership in power density.
• Mentor and grow the power density team: Build a culture of loss-awareness and power-density-first thinking. Mentor junior engineers on loss analysis, topology selection, and system integration. Create design guidelines and training materials.

Who You Are and What You Bring

• BS, MS, or PhD in Electrical Engineering, Power Electronics, or closely related field
• BS + 15 yrs | MS + 12 yrs | PhD + 8 yrs
• Candidates with greater experience are strongly encouraged to apply
• Deep knowledge of power converter topologies: Proven expertise in designing power converters across a range of power levels. Ability to select and optimize topology for specific voltage, power, and efficiency targets.
• Comprehensive loss mechanism analysis: Mastery of conduction, switching, magnetic, capacitive, and thermal loss mechanisms. Ability to derive loss equations from first principles, build loss budgets, and prioritize improvement opportunities based on impact.
• Power semiconductor device expertise: Deep understanding of state-of-the-art semiconductor device characteristics, loss models, and gate drive requirements. Experience selecting devices for high-frequency, high-voltage power conversion. Familiarity with device datasheets and how to extract accurate loss parameters.
• Strong communication and leadership: Ability to articulate loss budgets, trade-offs, and roadmap priorities to technical teams and leadership. Comfortable driving cross-functional initiatives and holding teams accountable to meet targets.
• Self-driven ownership: Ability to take full ownership of the power density roadmap and drive it to completion with high quality and on schedule.
• Solution-oriented thinking: Focus on identifying and implementing practical solutions rather than just identifying problems. Ability to quickly assess complex power density challenges, generate multiple solution paths, and select the most effective approach based on constraints, timeline, and impact.

The base pay range for this position is $130,000 to $226,000. This salary range may be modified in the future. The successful candidate's starting pay will be determined based on job-related skills, experience, education or training, work location, and market conditions. This position is also eligible for bonus, equity, and benefits.