Modelagem e Controle Das Tensões Dos Capacitores Flutuantes do Inversor com Grampeamento Através de Capacitores Flutuantes

Abstract

An active control method to balance the flying capacitor’s voltage is presented for a single-phase full-bridge flying capacitor inverter. Based on the equations of flying capacitors, an analytical method that represents the natural capacitor’s voltage balancing is introduced. In this technique, switches’ duty cycle is modified to control flying capacitor’s voltage using a proportional integrative controller. This method considers that current direction influences the capacitor’s voltage balance. The controller generates small differences between the switches’ duty cycle, which change the charge process of the capacitors. Simulation and experimental implementation results show that the control is efficient, maintaining the capacitor’s voltage regulated. Experimental results of the inverter applied to a photovoltaic system connected to the electrical grid are presented.