Developing power electronics products for the electric vehicle industry demands an uncompromising approach to quality. Chargers, on-board converters, and DC/DC modules operate in harsh environments, handle high voltages and currents, and must meet stringent safety and performance standards. At EVSELab, we have adopted the Advanced Product Quality Planning (APQP) framework as the backbone of our product development process, ensuring that every product we deliver meets the highest standards of reliability and performance.
What Is APQP?
APQP is a structured product development framework originally developed by the Automotive Industry Action Group (AIAG) in collaboration with Ford, General Motors, and Chrysler. It provides a standardized approach to planning and executing the steps required to bring a new product from concept to production while ensuring quality at every stage.
The Five Phases of APQP
The APQP framework consists of five sequential phases, each with defined deliverables and quality gates:
- Plan and Define Program — Establish scope, objectives, and customer requirements
- Product Design and Development — Create the product design, prototypes, and design verification
- Process Design and Development — Define manufacturing processes and validate production readiness
- Product and Process Validation — Confirm that the product and process meet all requirements
- Feedback, Assessment, and Corrective Action — Continuous improvement based on production data
APQP is not merely a quality checklist — it is a philosophy that embeds quality thinking into every decision, from the initial concept through volume production and beyond.
Phase 1: Plan and Define Program
Customer Requirements Capture
Every EVSELab project begins with a thorough understanding of customer and market requirements. For a typical EV charger development project, this includes:
- Electrical specifications: Input voltage range, output power, efficiency targets, power factor requirements
- Environmental specifications: Operating temperature range, humidity, IP rating, altitude
- Safety and regulatory requirements: IEC 61851, IEC 62368, UL certifications, CE marking
- Mechanical constraints: Form factor, weight limits, mounting requirements, connector types
- Cost targets: Bill of materials (BOM) cost, manufacturing cost, total landed cost
Technology Readiness Level (TRL) Assessment
We assess the technology readiness of key components and subsystems using the TRL scale (TRL 1–9):
- TRL 1–3: Basic research and proof of concept — typically handled in our R&D lab
- TRL 4–5: Component validation in laboratory environment — breadboard and bench testing
- TRL 6–7: System prototype demonstration — integrated prototype testing under representative conditions
- TRL 8–9: System complete and qualified — production-representative units passing all qualification tests
For projects incorporating novel technologies (such as new SiC MOSFET devices or advanced control algorithms), we identify the current TRL and define a clear path to TRL 9 before committing to the development timeline.
Risk Assessment and DFMEA
At this stage, we conduct an initial Design Failure Mode and Effects Analysis (DFMEA) to identify potential design risks. Common risk areas in EV charger development include:
- Thermal management under extreme ambient conditions
- EMC compliance with stringent automotive or industrial standards
- Component derating and reliability under long-term cycling
- Supply chain risks for critical semiconductors and magnetics
Phase 2: Product Design and Development
Schematic and Layout Design
Our hardware engineering team develops detailed schematics and PCB layouts following design rules derived from years of power electronics experience. Key design practices include:
- Power loop minimization: Keeping high-frequency switching loops as tight as possible to reduce parasitic inductance and EMI
- Thermal via arrays: Strategic placement of thermal vias under power semiconductors for effective heat extraction
- Creepage and clearance compliance: Ensuring all high-voltage layouts meet the required safety distances per IEC 60664 and IEC 62368
- Signal integrity: Proper routing of gate drive signals, current sense traces, and communication buses
Simulation and Analysis
Before committing to physical prototypes, we conduct extensive simulation:
- Circuit simulation (LTspice, PSIM): Verify topology operation, component stress, and control loop stability
- Thermal simulation (ANSYS Icepak): Model junction temperatures, airflow paths, and heatsink performance
- EMC pre-compliance simulation (CST, ANSYS HFSS): Predict conducted and radiated emissions
- Mechanical simulation (SolidWorks FEA): Analyze enclosure stress, vibration modes, and thermal expansion
Design Reviews
We conduct formal design reviews at defined milestones:
- Schematic review: Cross-functional review of circuit design, component selection, and safety compliance
- Layout review: Verification of PCB layout against design rules, manufacturing constraints, and EMC best practices
- BOM review: Assessment of component availability, cost, and second-source options
Phase 3: Process Design and Development
Manufacturing Process Planning
EVSELab works closely with our manufacturing partners to define production processes that ensure consistent quality:
- SMT (Surface Mount Technology) process parameters: Solder paste specifications, reflow profiles, inspection criteria
- Wave soldering and selective soldering: For through-hole power components and connectors
- Conformal coating: Process definition for products requiring environmental protection
- Final assembly: Mechanical assembly sequence, torque specifications, harness routing
Process FMEA (PFMEA)
We conduct a separate Process FMEA to identify manufacturing risks:
- Solder joint quality for large thermal pads (SiC MOSFETs, power modules)
- Component orientation errors for non-symmetric packages
- ESD sensitivity during handling of GaN and SiC devices
- Calibration accuracy for current and voltage measurement circuits
Test Strategy Definition
Our test strategy includes:
- In-Circuit Test (ICT): Verify component placement, solder integrity, and basic functionality
- Functional Test: Full power-up test at defined operating points
- Burn-in Test: Extended operation at elevated temperature to screen infant mortality failures
- Final QC Inspection: Visual and dimensional inspection before packaging
Phase 4: Product and Process Validation
Design Validation Testing (DVT)
DVT confirms that the product design meets all specified requirements. For EV chargers, typical DVT includes:
- Efficiency measurement across the full operating range (input voltage, output power, temperature)
- Thermal characterization: Junction temperature mapping at maximum power under worst-case ambient conditions
- EMC testing: Conducted emissions (CISPR 11/32), radiated emissions, immunity (IEC 61000-4 series)
- Safety testing: Dielectric withstand, insulation resistance, earth continuity, leakage current
- Environmental testing: Temperature cycling (-40 to +85 degrees C), humidity (85/85), vibration, salt spray (if applicable)
- Reliability testing: Accelerated life testing, power cycling, HALT (Highly Accelerated Life Testing)
Production Validation Testing (PVT)
PVT confirms that the manufacturing process produces units that consistently meet the design specifications. This involves:
- Building a production-representative batch (typically 50–200 units)
- Running the full test sequence on every unit
- Statistical analysis of key performance parameters (efficiency, power factor, THD, output ripple)
- Cpk analysis to verify process capability
PPAP (Production Part Approval Process)
For automotive customers, we prepare a full PPAP package including:
- Part submission warrant
- Design records and engineering change documentation
- DFMEA and PFMEA
- Control plan
- Measurement system analysis (MSA)
- Dimensional results
- Material and performance test results
- Process flow diagram
- Sample parts
Phase 5: Feedback, Assessment, and Corrective Action
Continuous Improvement
Product launch is not the end of the APQP process. We maintain active feedback loops:
- Field failure analysis: Every returned unit undergoes root cause analysis
- Production yield monitoring: Weekly tracking of production yield and defect Pareto
- Customer feedback integration: Structured process for incorporating field feedback into design improvements
- Lessons learned database: Documented learnings from each project feed into our organizational knowledge base
Design Iteration
When field data or customer feedback indicates an improvement opportunity, we follow a structured engineering change process:
- Engineering Change Request (ECR) with detailed justification
- Impact analysis across affected products and processes
- Verification testing of the proposed change
- Controlled implementation with before/after validation
Why APQP Matters for EV Charging
The EV charging industry is at an inflection point. As charging infrastructure scales from thousands to millions of units globally, product quality and reliability become critical differentiators. Charger downtime directly impacts EV driver experience and operator revenue. Safety failures can have severe consequences.
By following the APQP framework, EVSELab ensures that our products are not just technically innovative, but also:
- Reliable: Designed and validated for the full expected service life
- Manufacturable: Optimized for consistent, high-yield production
- Compliant: Meeting all applicable safety, EMC, and performance standards
- Traceable: Full documentation from concept through production
Conclusion
The APQP framework provides EVSELab with a proven, systematic approach to product development that balances innovation with discipline. In an industry where the stakes are high and the requirements are demanding, this structured methodology gives our customers confidence that every product we deliver has been rigorously planned, designed, validated, and produced to the highest quality standards.
Want to learn more about EVSELab’s product development process? Contact us to discuss how our engineering methodology can benefit your project.
