Fuzzy controller based active power line conditioner for harmonic mitigation

Abstract

The expeditious rise in power semiconductor devices led to the evolution of many power electronic loads for improving controllability and system efficiency. These loads are non-linear in nature and draw non sinusoidal current. Typical examples include electric arc furnace, variable frequency drives, rectifier circuits, switched mode power supply, compact fluorescent lamps, etc. The non-linear loads inject harmonics into the supply and affect the customers having linear loads connected to the same Point of Common Coupling (PCC). The sensitive loads like microelectronics based equipment in hospitals, home appliances such as video player and digital computers connected at that PCC are also affected. In order to protect these sensitive loads, several standards have been developed such as Institute of Electrical and Electronics Engineers (IEEE) 519, International Electro-technical Commission (IEC) 61000 that clearly indicate the limit on voltage and current harmonics that can be injected at PCC. Numerous solutions have been addressed in literature for reducing harmonics such as passive filters, series Active Power Filters (APF) or Active Power Line Conditioners (APLC), shunt APLCs and hybrid filters. The shortcomings of passive filters are their bulky size, providing compensation only for tuned frequencies and causing resonance with system impedance. Hence the use of APLCs for harmonic alleviation is suggested by many authors. Now a days high power Alternating Current (AC) and Direct Current (DC) drives are being used for speed control applications in many industries. The harmonics produced by these high power drives cannot be alleviated using conventional two-level APLC newline