Zero Voltage Switching AC-DC Converter Based on Zero State Modulation

Power conversion is required in many applications including grid-interfacing battery storage, solar, fuel-cell and electric vehicle chargers. Converting from AC to DC power using a power convertor is critical, but its size, cost and performance have not been optimized. The increase in switching frequency reduces the size of inductors/capacitors and improves control, but often results in switching loss and electromagnetic interference (EMI). This technology is a novel implementation of an AC to DC power converter that will allow the converter to operate at high switching frequencies while minimizing switching loss and EMI and improving power density. 

Description

This technology can achieve zero voltage switching (ZVS) across the whole operating region of an AC-DC power converter while maintaining constant frequency operation, which is not possible with current technologies. This approach allows for a simplified filter design, and has an extremely small filter inductor requirement, up to 20 times smaller than a typical hard switching converter. The control is based on fixed frequency approach, which allows interleaving that can result in a reduced filter capacitor requirement. This AC-DC converter with its improvements in efficiency, cost, size and performance can be used in multiple applications such as grid-interfacing photovoltaic cells, grid-interfacing storage, EV drives, and cascaded H-bridge based millivolt converters. The proposed converter is applicable for three phase-three wire DC-AC, three phase-four wire DC-AC, single-phase DC-AC and DC-DC applications. 

Applications and Industries

• Solar converters 
• Fuel-cell converters 
• Battery storage converters 
• Any industry that uses power conversion 

Benefits

• Reduces loss in power conversion process 
• Reduces high frequency noise from EMI in power conversion process 
• Highly efficient 
• Compact 
• High frequency 
• High energy density 
• New topology 

Contact 

To learn more about this technology, email partnerships@ornl.gov or call 865-574-1051.