This study aims to propose a more effective fuzzy logic controller (FLC) to achieve minimum deviation in frequency and power of an isolated hybrid power system. Here, in the FLC, scaling factor has been introduced and are optimized by using quasi opposition harmony search (QOHS) algorithm along with the other tunable parameters of the considered system. Performances of the scaling factor based FLC’s are compared with their corresponding proportional-integral-derivative controller, in terms of several performance measures such as integral absolute error (IAE), integral of multiplied absolute error (ITAE), integral square error (ISE) and integral of time multiplied square error (ITSE), in addition to the deviation due to step load perturbations. In each case, the scaling factor based FLC model shows an extraordinarily upgraded performance over its conventional counterpart.