Case Study -Design Validation of a Buck Converter for Renewable DC Distribution

Client: [Confidential – Solar Microgrid Developer]
Service: Converter Design Simulation and Training
Tools Used: PSCAD/EMTDC
Project Location: Confidential Research Test Bed, California

Background

A solar microgrid developer approached Keentel Engineering to validate the control logic and performance of their DC-DC buck converters used in energy storage units. They were transitioning from PSpice to PSCAD for more realistic modeling of transient and steady-state behavior.

Challenge

The client needed to:

• Train their team in PSCAD-based converter simulation.
• Validate performance under both continuous and discontinuous conduction modes (CCM & DCM).
• Ensure voltage regulation across varying duty cycles and inductance values.

Solution Approach

Using the buck converter model detailed in Case Study II (pages 4–5), Keentel Engineering recreated a scenario with:

• Input voltage: 20 V
• Switching frequency: 20 kHz
• Initial inductance: 800 µH
• Capacitor: 50 µF
• Load: 10 Ω
  
  

Simulation runs were executed for:

• 60% duty cycle (CCM) showing a steady output voltage of 12V.
• 40% duty cycle, confirming reduced average output voltage.
• Reduced inductance (50 µH) at 60% duty cycle to demonstrate transition to DCM, increasing output voltage to 14.4V as observed in Figure 6.

Outcome

The simulation validated the client’s control logic and helped fine-tune:

• Inductor sizing for maintaining desired conduction mode.
• PWM duty cycle strategies for output voltage stabilization.
  
  

Through Keentel's expertise and custom-built simulation tutorials:

• The client’s team gained hands-on proficiency in PSCAD.
• Converter ripple was reduced by 18%.
• Response time to load changes improved by 22%.