Single-phase power factor correction (PFC) circuits, a class of front-end ac/dc converters widely used in consumer electronics, are also foundational to ac charging systems for electric vehicles (EVs). These circuits are used in onboard chargers (OBCs), wallboxes, and portable EV supply equipment (EVSE), where they shape grid current, meet regulatory requirements, and supply stable dc voltage for downstream conversion stages.
Researchers develop a sensorless boost PFC method delivering near 0.9998 power factor and low distortion, enabling smaller and more reliable power supplies for electronics.
Researchers have developed a sensorless boost PFC control method that achieves near-unity power factor and low total harmonic distortion, enabling simpler and potentially more reliable ac/dc power conversion.
Improvements at the PFC stage can directly affect EV ac charging system efficiency, size, cost, and long-term reliability, particularly in Level 1 and Level 2 charging applications.
Conventional boost PFC converters rely on current sensors, which can introduce noise sensitivity, signal delay, added hardware complexity, and additional failure points. In EV charging systems, these limitations can affect electromagnetic compatibility, calibration stability, and durability over extended operating lifetimes. By eliminating the current sensor, the proposed control strategy reduces component count, improves noise immunity, and simplifies circuit design.
The research was conducted by a team from South Korea and China, led by Sung-Jun Park, Professor in the Department of Electrical Engineering at Chonnam National University, and published in IEEE Transactions on Consumer Electronics. The method uses a single voltage-loop control structure derived from the inductor voltage relationship, with delay compensation to address phase lag that can distort input current in digitally controlled PFC systems.
The approach avoids complex observers and detailed mathematical models, allowing implementation on standard digital signal processors without major architectural changes. Low sensitivity to circuit parameter variation supports suitability for high-volume manufacturing, including applications where long-term stability and reduced maintenance are priorities.
The control method was validated on a 1.3-kW prototype, achieving a power factor of up to 0.9998 and total harmonic distortion of 2.12% at full load. While demonstrated at consumer-electronics power levels, the underlying PFC control strategy is applicable to the front-end ac/dc stages used in EV onboard chargers and ac charging infrastructure, where cleaner grid interaction and reduced hardware complexity can support scalable deployment.
“As millions of electronic devices draw cleaner, sinusoidal current — with high power factor and low THD — from the wall socket, it reduces stress on the power grid. Lastly, cheaper and more reliable power supplies could mean lower upfront costs for consumers, furthering electric vehicles and renewable energy systems,” explained Park.
Filed Under: Charging, Onboard Charging, Technology News