New chip control method cuts power converter losses by up to 35%
Researchers have demonstrated a variable switching frequency technique that reduces energy losses in power converters used in renewable energy systems and electric vehicle chargers. The method improves efficiency across a wide operating range, offering manufacturers a straightforward way to cut costs and heat generation without redesigning hardware.
Originaltitel: A Variable Switching Frequency Control Technique for DC-AC Flying Capacitor Multilevel Converters to Improve Efficiency and Inductor Utilization
<p>This work proposes a variable switching frequency scheme for a flying capacitor multilevel (FCML) converter in dc-ac operation to better utilize the output inductor for its rated peak-to-peak current ripple and substantially reduce converter losses over the ac line cycle. The proposed technique holds the inductor current ripple constant by leveraging the duty-cycle dependent inductor current ripple, and variably changes the switching frequency to hold this constant at its rated design value. Practical lower switching limits are taken into consideration in developing this approach, and experimental results validate the feasibility in a common micro-controller framework. Hardware results are provided for a 400 Vdc to 240 Vrms 6-level FCML inverter and showcase loss reductions on the order of 10 − 35% across the measured power range, compared to conventional control with fixed frequency operation.</p>