Abstract
Solar energy is more attractive and acceptable as one of available power sources in future from a view point of a clean and inexhaustible power supply. However, the electric power generated from a solar photovoltaic array largely depends on weather conditions. Therefore a constant mechanical power can not be obtained from one motor which is driven on the basis of the electric power from a solar photovoltaic array. In order to produce a stable mechanical power, the authors propose the parallel operation system using two induction machines.
This paper presents on the stability of the proposed system in which the machine A is related to a solar phtovoltaic array coupled with a general purpose inverter and another machine B is interconnected directly to the utility-grid AC line. It is shown that the system can generate a stable mechanical power with cooperation of the machine B even if the output power of the machine A becomes zero. Furthermore the operating frequency of the inverter is determined by utilizing the relation of the maximum power and the optimal operating voltage of a solar photovoltaic array. As a result, the output power of the machine A becomes always a maximum value under variable weather conditions.
