Accurate Analysis of the Control-to-Output Transfer Function of a Boost-Converter including Aliasing Effects of PWM Generation

A fast response to load changes of a power converter requires appropriate control loop design and, therefore, knowledge about the transfer functions. In contrast to the approximated control-to-output transfer function of commonly used averaging methods, in this paper, the accurate transfer function is simulated for a boost-converter by a time domain perturbation. Subsequently to a single-frequency sinusoidal perturbation, for reduced computing effort, a multi-frequency rectangular perturbation signal is introduced. It is shown that due to aliasing effects, compensation with the discrete Fourier transformation of the discrete duty cycle values, and a phase correction factor is necessary. This correction mechanism is then applied to the multi-frequency perturbation methods maximum-length binary sequence and discrete-interval binary sequence.