A Generalized Predictive Controlled T-type power inverter with a deterministic dc-link capacitor voltage balancing approach

Abstract

The thesis consists of implementing a Generalized Predictive Control (GPC) strategy for controlling the output voltage of the T-type converter with output LC filter, whose control signals are modulated by a fast three-dimensional Space Vector Modulation (SVM). The GPC strategy used for the T-type converter involves developing a system of dynamic equations from the output LC filter and load, which is transformed to a Controlled Auto-Regressive and Moving-Average (CARIMA) model in order to obtain a sequence of control signals, so that a cost function is optimized and the reference is tracked. The core of the thesis addresses the main problem of dc-link capacitor balancing. This is done by modeling the converter and deploying a mathematical analysis of the capacitor voltage difference dynamics, by singular perturbation approach. This analysis results in an explicit sinusoidal disturbance. Now, classical control theory is applied by using a Luenberger Observer (LO) in order to estimate the disturbance and encounter it, thereby keeping the dc-link capacitor voltage balanced in the due flow of the modulation and output voltage control. By this method, the output voltage across the filter capacitor is controlled, the dc-link capacitor voltage is balanced and the lowfrequency voltage ripples present in the dc-link of the T-type converter are reduced to an acceptable level.Máster en Electrónica, Tratamiento de Señal y Comunicacione