Fuzzy Based Digital Automatic Voltage Regulator of a Synchronous Generator with Unbalanced Loads

Voltage stability and power quality of the electrical systems depend on proper operation of the Automatic Voltage Regulators (AVR) of generators. Nowadays, design technology of the AVRs is being broadly improved. According to wide range operating conditions of the generators and loads, the fuzzy AVRs are going to be the modern type of regulators, particularly, for the genset alternators operating in distribution systems. There are many research presented on the optimum performance of the fuzzy AVRs. They are focused mostly on the balanced loads with minor attention to the unbalanced loads and voltages that are very common for the generating sets embedded in distribution systems. In this study, performances of a simulated digital fuzzy AVR evaluated for a wide range of unbalanced loads operating conditions. Feedback signals, sampling time and scaling factors of fuzzy logic based controller have significant impacts on the overall system performance. A few quality indices are specified and their values are compared for different feedback signals and various unbalanced operating conditions and accordingly, the optimum feedback signal is introduced.