Switching Converters Dynamics Considering Non-Ideality of the Error Amplifier within the Analogue Control System

Abstract

The paper discusses a pulse voltage converter with a high switching frequency of a switch with an analog control system capable of providing the required conversion frequencies. The pulsed voltage converter under study has a control system with a proportional-integral regulator, implemented on the basis of a general-purpose operational amplifier. Operational amplifiers with such parameters are widely used as part of modern control microcircuits for pulse-width converters. In this work, the influence of the technological spread of the gain of the operational amplifier on the dynamics of the converter is studied. The studies were carried out both using the developed nonlinear dynamic model of the system, and using a small-signal open-loop dynamic model. A technique has been developed for selecting the parameters of the controller, taking into account the technological spread of the gain of the operational amplifier based on a nonlinear dynamic model. An analysis of the results obtained using a nonlinear dynamic model showed a significant influence of the specified spread on the dynamics of the system, even when the cutoff frequency of the open-loop control system is significantly removed from the frequency of the high-frequency pole of the operational amplifier. This must be taken into account when designing pulse voltage converters with analog control systems, namely, when choosing the parameters of regulators. It is shown that with the optimal values of the controller, selected according to the proposed method, the effect of technological gain spread on the frequency characteristics of an open circuit in the low-mid frequency regions is minimal, which indicates the effectiveness of the method.