Abstract: The present invention provides systems and methods for reducing harmonics, for example when using an AC to AC converter to drive a load such as a motor drive. In a first embodiment, a plurality of load driving circuits is provided, each drawing current from a 3-phase AC supply and driving an AC load, wherein each of said load driving circuit includes a 3-phase rectifier, with the rectifiers of the load driving circuits being controlled such that the rectification of the AC supply by the load driving circuits is staggered. In a second embodiment, a load driving circuit comprises an electronic inductor configured to control the DC link voltage and/or current such that the current drawn from the AC supply by the load driving circuit has a stepped profile. The first and second embodiments may be combined.

Abstract: The present invention provides systems and methods for reducing harmonics, for example when using an AC to AC converter to drive a load such as a motor drive. In a first embodiment, a plurality of AC/DC converter stages are connected in parallel between a 3-phase AC supply and a DC link, each of said AC/DC stages including a 3-phase rectifier, with the rectifiers of the load driving circuits being configured such that the rectification of the AC supply by the load driving circuits is staggered. Blocking diodes are used to prevent current circulation from one rectifier to another.

Abstract: The present invention provides systems and methods for reducing harmonics, for example when using an AC to AC converter to drive a load such as a motor drive. In a first embodiment, a plurality of load driving circuits is provided, each drawing current from a 3-phase AC supply and driving an AC load, wherein each of said load driving circuit includes a 3-phase rectifier, with the rectifiers of the load driving circuits being controlled such that the rectification of the AC supply by the load driving circuits is staggered. In a second embodiment, a load driving circuit comprises an electronic inductor configured to control the DC link voltage and/or current such that the current drawn from the AC supply by the load driving circuit has a stepped profile. The first and second embodiments may be combined.