A Practical Implementation of a Two-Stage 350-W Universal Charger for Power Mobility Device Charging Applications

Area of Science:

• Electrical Engineering
• Power Electronics
• Renewable Energy Systems

Background:

• Power Mobility Devices (PMDs) require efficient and reliable charging solutions.
• Existing chargers may lack universal compatibility or optimal efficiency across various loads.
• Adherence to stringent safety standards (IEC 61000-3-2, CISPR 22) is critical for grid-interfaced power electronics.

Purpose of the Study:

• To develop and validate a universal, two-stage charger for PMDs.
• To achieve high efficiency and reliable performance for electric wheelchairs and scooters.
• To ensure compliance with international safety and electromagnetic compatibility standards.

Main Methods:

• Implementation of a rectifier-boost power factor correction (PFC) topology for AC grid interface.
• Design of a dual-loop controller for an LLC resonant converter with a wide operation region.
• Comprehensive design, implementation, and rigorous testing of the charger's key aspects.

Main Results:

• The PFC stage achieves ≈96% efficiency across all loading conditions, establishing a ≈386-VDC bus.
• The LLC converter achieves a peak efficiency of 95.5%, resulting in a two-stage charger efficiency of 91.6%.
• The charger successfully passed all power factor (PF), total harmonic distortion (THD), and conducted EMI safety requirements.

Conclusions:

• The developed two-stage (PFC+LLC) charger offers a universal and efficient solution for PMD charging.
• The design provides a practical guide for the development and testing of high-performance power electronic chargers.
• The charger meets critical safety and regulatory standards, ensuring safe and reliable operation.