Development of Control Techniques Using Modified Fuzzy Based SAPF for Power Quality Enhancement


Low power distribution systems have severe power quality issues due to the non-linearity of several residential and industrial loads. The main power quality issue is the harmonics leading to the overheating of the transformers in the distribution systems. By employing passive filters, active filters, and custom power devices, the harmonics in the source current can be reduced. To overcome the drawbacks of conventional tuned filters and active power filters the modified shunt active power filter was introduced with the fuzzy logic controller.


In this paper, an effective way of reducing the total harmonic distortion using three-phase three-wire shunt active filter is carried out and this has been investigated through three control methods namely synchronous reference frame theory, real and reactive power theory, and indirect reference current theory. The recognized control methods are implemented with the fuzzy controller to improve the performance of the induction motor drive. The hardware setupwas implemented for the proposed fuzzy-based control technique to achieve better performance in terms of reduced total harmonic distortion and DC link voltage and improved speed performance of induction motor drive when compared to other control methods. Further power factor correction and better reactive power compensation are achieved by implementing hardware.


  1. Power quality
  2. SPAF
  3. FUZZY controller
  4. Total harmonics distortion
  5. DC link voltage
  6. Induction motor drives



Figure 1. Schematic Representation Of The Srf Control Technique For Shunt Apf.


Figure 2. Voltage And Current Waveforms Of Sapf Using Srf Method (A) Source Voltage (B) Load Current (C) Voltage At Pcc (D) Source Current (E) Filter Current (F) Dc Link Voltage.

Figure 3. A To C Active And Reactive Power Of Sapf: A) By Irct Method B) By P-Q Method C) By Srf Method.

Figure 4. A To C Power Factor Of Sapf: A) By Irct Method B) By P-Q Method C) By Srf Method.

Figure 5. Capacitor Dc-Link Voltage Of Three Control Strategies.

Figure 6. Voltage And Current Waveforms Of Sapf With An Induction Motor Drive Load (A) Input Voltage (B) Load Current (C) Voltage At Pcc (D) Input Current (E) Filter Current (F) Dc Link Voltage.

Figure 7. Rotor Current, Speed In Rad./Sec. And Torque Of Induction Motor Drive.


The simulating of the non-linear system of bridge rectifier with and without SAPF has been analyzed.The % THD has been decreased from 63.8 % to 0.48 % in the SRF method,2.04 % in the p-q method,6.67 % in the IRCT method,1.30 % for the induction motor drive load,1.07 % for the different load is considered. The hardware setup as implemented for the proposed work and the Power factor is improved by the percentage of 6.38 %, Reactive power compensation is achieved up to 88.3 % and Source current harmonics is reduced from 23.9 % to 3.2 %.The system has been analyzed with two types of load. For the bridge rectifier load, the total harmonic distortion was reduced to 0.48 %. In the induction motor drive load the % THD is reduced to 1.30%,It shows that the active filter is providing reduced % THD for the different types of load and the robust speed performance has been achieved using fuzzy-based SAPF techniques.


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