A unified method to the design of an improved high frequency sliding mode current controller for DC/DC boost converter in continuous current condition based on analogue implementation

Abstract

In this study, an improved high frequency sliding mode current controller is proposed for DC/DC power converters in continuous current condition using analogue-based implementation. The sliding mode control is a variable frequency method. In this strategy, the controller frequency is a function of summation of all time delays of different parts of control circuit. If these delays increase, the switching frequency extremely decreases, steady error of the output voltage increases; and also, the converter frequency may be less than the audible frequency. In practical applications, it is extremely important that the output voltage tracks exactly its reference signal. Moreover, the switching frequency of a power converter must be more than $$ 20\;{\text{kHz}} $$ in practice. A good way for enhancement of the switching frequency and dynamical performance of the sliding mode method is to use all state variables of the controlled system in the sliding manifold. This attempt has been made for the voltage regulation and input current control of a typical Boost converter in this paper. Using sliding mode theory and Filippov’s method, the stability of the suggested controller is established. Simulations and practical implementation of the proposed system show that the developed controller is successful to control the converter at high frequencies by removing the voltage error in steady region, despite using low speed and cheap electrical devices in the control circuit.