Self-Synchronized Multifrequency Plant Measurement of a Boost Converter

Inhalt:
The design of analog controllers for DC-DC converters requires their small-signal plant. It is commonly measured by a gain-phase analyzer, performing a time-consuming frequency sweep. To reduce measurement time, this paper proposes a faster, self-synchronized multifrequency excitation method. A microcontroller detects the edges of the PWM-signal and – in each period – injects a new perturbation bit to the feedback-path. Measurement of the output voltage and control signal in time domain deliver the transfer function when compensating the aliasing effects. The measurement results for a boost converter, performed with multiple common binary excitation signals, show excellent agreements with the conventional sine sweep.