Student Number : 0400486V - MSc (Eng) dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / The Voltage Dip Test Facility at the University of the Witwatersrand utilises a resistive load during testing of variable speed drives. This method produces valuable results regarding the performance of drives under dip conditions. It has been shown that load type does influence the performance of drives and this variation cannot be tested under current conditions as only linear loading is attainable with resistive loads. This thesis proposes a programmable load based on the concept of field-oriented control of an induction motor. The concepts involved with field-oriented control are discussed and shown to be suitable for this application. An implementation strategy utilising custom-designed software and an off-the-shelf VSD is developed and executed. The performance of the programmable load is analysed under both steady-state and dynamic conditions.

The diploma thesis deals with the design of a programmable load. As first, the research of available commercial devices was made in the theoretical part. Based on this research, the design possibilities of programmable load were discussed. As next, the design of resistor network was made, using a computer program that was developed for this purpose. Practical part deals with a realization of module of load, control board and software development. Proposed system consists of control board and ten modules. Modules have floating input terminals. This approach facilitate to arbitrary combination of their inputs. Modules are designed to work with DC and AC power supplies.