The transition to electric vehicles (EVs) is essential for reducing fossil fuel
consumption. However, fast and ultra-fast charging remains challenging due to
high energy losses, large voltage ripples, and bulky, expensive components.
Existing power converters often suffer from inefficiency, voltage stress on
switches, and the need for large storage capacitors, reducing reliability and
increasing costs.
Core Features and Innovation
This invention introduces a bridgeless single-stage AC-DC CLLC resonant converter that eliminates diode bridge rectifiers to reduce power loss. It features soft-switching operation for minimal voltage stress and high efficiency, achieving over 96% efficiency and a power factor correction (PFC) above 0.98. Additionally, the converter employs an active voltage ripple reduction control scheme that minimizes output ripple to just 1.4% without bulky capacitors. A Variable Frequency Modulation (VFM) control algorithm ensures consistent output voltage, while the stacked switch configuration reduces voltage stress on each switch by half, making it suitable for high-voltage (800V) battery systems.
Novelty and Advantages
Unlike conventional converters, which are prone to high power loss and require large capacitors for voltage ripple reduction, this system achieves efficient power conversion in a single stage. By integrating ripple reduction directly into the system without adding complex auxiliary circuits, it significantly improves reliability and longevity.
Benefits
1. Reduced Energy Loss: Lower power loss and high efficiency.
2. Compact Design: Smaller, lighter, and more reliable due to reduced capacitor size.
3. Fast Charging: Supports high-voltage EV battery systems with stable output.
4. Enhanced Durability: Soft-switching operation increases the lifespan of components.
Broader Impact
This innovation supports faster, more reliable EV charging, promoting the widespread adoption of electric vehicles. By minimizing power loss and maintaining a high-power factor, it contributes to sustainable energy management and a reduction in greenhouse gas emissions.