TIDUF18A October 2022 – February 2024
Resonant converters are typically most efficient when operating at or near the resonant frequency. Since this is a bidirectional battery charger, this design needs to cover a range of output voltages. This implies that n should be chosen such that the converter operates at as low a current as possible to help reduce I2R losses. Following this design concept the highest output current will occur at the lowest output voltage at which you need to supply full power. We will set n at this point such that the converter operates as close to resonance as possible. In this design this works out to be a turns ratio of 1.1:1. This enables the lowest losses while still allowing for a wide output voltage range.