Discontinuos carrier-based modulation for three level flying capacitor converter

Abstract

This paper presents a discrete time controller for the voltage balancig of three-level flying capacitor converter that uses carried-based discontinuous modulation. The discontinuous modulation produces multilevel equivalent PWM line-to-line output voltages with reduced harmonic distortion and equally distributes the commutations among the switches. A state machine is used to reduce the number of commutations. Using this state machine a nonlinear controller is proposed to make it possible to control the voltage of the flying capacitors. Moreover, it is important to mention that the implementation of the proposed modulation and controller is straightforward, requiring neither a complex hardware nor a high computation effort. Finally, results from a hardware in the loop implemented using the TMS320355 are given to validate the theoretical development.