Harmony of Efficiency and Control
Synchronous average harmonic current (SAHC) compensation technology provides flexible control of efficient resonant power architectures with improved load invariance. Prior control methods based on rectification may exhibit load dependent gain behavior. Our innovative technology has a well defined voltage gain relationship, (n·sin(πd1)/sin(πd2)), plotted below.
A buck mode is shown using control of a first duty cycle signal, d1, and a boost mode is shown using control of a second duty cycle signal, d2. An additional regulation mode is made possible by setting d1 equal to d2, resulting in a unit gain between an input and output. These regulation modes support designs for simple DC/DC conversion as well as design applications with multiport (AC&DC)/(DC&AC) connectivity.
The control relationship for our converter is illustrated in the following figure in comparison to classic architectures. A typical power stage and control degrees of freedom are shown for each respective architecture. The classic variable frequency resonant power supply architecture (a) enables efficient power switch utilization and favorable magnetic integration. However the classic architecture exhibits undesirable load dependent behavior which makes design integration difficult. Classic phase shift power supplies (b) are a type of current controlled architecture which require additional feedback sensing and filtering to result in low impedance load independent voltage gain. The classic synchronous buck-boost converter (c) is a robust architecture which allows flexible voltage gain, but may have efficiency tradeoffs with respect to switch operation, magnetic integration, and parts count. Our synchronous average harmonic converter (d) shares positive aspects of the classic resonant power supply (a) and the classic buck boost converter (c) such as efficiency and improved load independence.
