Implementation of harmonics power factor meter using fuzzy logic [articol]

Abstract

In linear load conditions, power factor definition is unique. However increased use of power electronic devices, adjustable speed drives, and other nonlinear loads, causes the voltage and current waveforms to become non sinusoidal and highly distorted. In such a situation, different power factors are proposed. In this paper a new fuzzy based harmonics power factor (FHPF) meter is introduced to represent these power factors as a single index. The proposed harmonics power factor amalgamates the recommended PQIs, such as displacement power factor, transmission efficiency power factor and oscillation power factor. The FHPF was applied to non linear load with different distortion cases under, sinusoidal and non sinusoidal conditions. Considering the advantages of the fuzzy systems such as simplicity, ease of application, flexibility, speed and ability to deal with imprecision and uncertainties, this factor can be useful for power quality evaluation, cost-effective analysis of PQ mitigation techniques and billing purposes. It is shown that the new FHPF is expressive and accurately represents the existing power quality indices in all cases and in all situations. MATLAB simulations are performed. A hardware prototype of FHPF meter is developed using PIC. The current and voltage signals are sampled and the different power factors are calculated. Fuzzy logic coding is done and using a LCD, the index is displayed. The results are promising for implementation.