Design and Implementation of a Two-Stage Grid-Connected High Efficiency Power Load Emulator

The need to reduce the time consumption in developing and implementing power converters, and to improve the effectiveness of the test equipment, continues to grow. This trend is further accelerated through the development of electricity-based technology, such as the electric or hybrid vehicle. As the price of energy continues to increase, regenerative test equipment used for validating power converters are gaining importance and attention. This paper focuses on the development of a two-stage regenerative power load emulator. This type of intelligent load requires a connection to the network interface, which, for some applications, should be bidirectional and must possess a galvanic isolation. The development of such grid-connected unit that processes ac-dc conversion is treated in this paper. A 5 kW prototype is used as a base to model, simulate, design, implement, and test such a system. The stability of the interconnection between the two conversion stages is established and tested in real-time applications. The prototype was tested at 180, 220, and 260 V RMS. The measured efficiency is higher than 90%, and the power factor is 0.99 over a wide range of operation.