Impact of PWM methods and load configuration in the design of intercell transformers used in parallel three-phase inverters

Interleaving techniques applied to the parallel association of converters provide the reduction of the output current ripple and the increase of its frequency, leading to a reduction of the associated filters. The best way of paralleling commutation cells is by means of InterCell Transformers (ICT). The design of such special magnetic components strongly depends on the magnetic flux flowing through their core. This flux is modified by different PWM methods if ICTs are used in three-phase systems. The main objective of the paper is to show how different PWM methods (related to the carrier disposition and also to zero sequence signal injection) influence the flux inside ICTs used in different topologies of three-phase systems. In addition, the most popular PWM methods are compared in order to find the best ones regarding the flux in the ICT. Experimental results validate the analysis presented in this work as well as the reduction on the ICT flux provided by the optimal zero sequence signals.