A Novel Four-in-One Variable Frequency Drive Topology

Of late, most types of ac motors can be operated using variable frequency drives (VFDs) by merely selecting the type of motor and the corresponding control method using a sophisticated all-in-one software platform. As technology improves, the VFD is becoming more of a plug and play, software-based electrical equipment. There have been no comparable technological advancement/improvements in the hardware realm except for the potential use of wide band gap devices (SiC or GaN) to reduce losses. The idea being proposed here is a hardware platform that is similar to an all-in-one software platform. By reconfiguring the hardware platform, one could achieve totally new or additional features that can enhance the overall performance of a VFD. It is shown that by adding one small hardware device as part of the main VFD, the unit can be reconfigured to provide four distinct features/functions as desired. An off-the-shelf VFD is used as an example to illustrate the various configurations achievable based on the proposed hardware modification. The proposed topology's cost, size, and features are compared with a traditional VFD with externally added components to achieve similar features/functions. In addition, the amount of time estimated to be saved in developing the proposed four-in-one converter compared to developing individual, external units to achieve similar features and functions is also investigated.