Experimental Validation of the Harmonic Cancellation Technique

Harmonic Cancellation Technique (HCT) is a modulation technique which has been developed to reduce the output voltage THD of three phase voltage source inverters (VSI) when they are used to feed simultaneously both linear and non-liner loads. The HCT is based on the proper pre-distortion of the inverter output voltage in order to cancel out the low frequency harmonic content due to the non linear load operation. The theoretical development of this technique has been carried out and presented in previous works. However, the main objective of the present paper is focused on the experimental implementation of the aforementioned modulation technique. Thus, the main aspects related to the obtaining of a successful practical implementation of the HCT are described in detail. For this aim, a complete set of experimental results have been obtained by means of a typical railway converter and are shown in this paper.