Modified PWM Technique for Harmonic Reduction

Abstract

This paper presents a Shunt Active Filter (SAF) based on the Variable Index Pulse Width Modulation approach. In the proposed method of Pulse Width Modulation (PWM), the triangular wave is derived by integration of the reference signals. This method introduces two basic advantages; the first one is that the triangular signal contains the information of the signal to be obtained in output and the second advantage is that its amplitude is varied in proportion to the amplitude of the reference signal. Therefore, in this PWM method, the modulation index is varied according to the variation of the reference signal, so it is termed as Variable Index Pulse Width Modulation. In order to demonstrate the validity of the proposed method, the obtained simulation results are compared with results of the Space Vector Modulation (SVM) approach. Furthermore, it is shown that in the case of nonsinusoidal voltages, the SAF with the proposed control strategy can provide the filtering action. This method is quite easy to implement and requires lower circuitry. The results show that the proposed method can satisfy the IEEE-519 standard regarding the reduction of harmonics.

A Simplified Method of Improving the Power Quality in Power Electronic Circuits using a Single Pair of IGBTs

“…Without electricity, the whole world will plunge into darkness, with the country's economy falling drastically -after all, every working device requires electricity. The world, therefore, should grateful to Thomas Alva Edison and Benjamin Franklin, Who discovered this great wonder, a thing of great importance today [21][22][23][24][25][26][27][28][29][30].…”

Enhanced Instantaneous Power Theory with Average Algorithm for Indirect Current Controlled Three-Level Inverter-Based Shunt Active Power Filter under Dynamic State Conditions

“…In recent years, various research works on this particular algorithm have been reported in the literature including Synchronous Reference Frame (SRF) [12,13], Instantaneous Power (PQ) Theory [11,[14][15][16][17][18], DQ-axis with Fourier (DQF) [19], Fast Fourier Transform (FFT) [20], Synchronous Detection (SD) [21,22], wavelet-based approach [23], and Artificial Neural Network (ANN) [24,25]. Among all the existing algorithms, PQ Theory has advantages over the others such as simple design, increased speed, and fewer calculations, making it more likely to be implemented practically.…”

“…However, the latest trend in PQ Theory algorithm is still applying numerical filters such as low pass filter (LPF) [14,[16][17][18], both LPF and high pass filter (HPF) [11], and band reject filter (BRF) [15] to detect the desired real power signal for reference current generation. The dependency on these sluggish numerical filters is the main factor that limits the harmonics extraction performance which in turn degrades the overall harmonics mitigation result.…”

“…Besides that, another weakness of the conventional PQ Theory algorithm is related to the characteristic of its generated reference current. To date, the nonsinusoidal reference current is mainly derived from the extracted current harmonics [11,[14][15][16][17][18] and thus forces the SAPF to operate based on direct current controlled (DCC) scheme [26][27][28] where the knowledge of actual SAPF injection current is required in generating the desired PWM switching signals to control the switching activities of SAPF for harmonics mitigation.…”

Intensive random carrier pulse width modulation for induction motor drives based on hopping between discrete carrier frequencies

“…The sinusoidal PWM (SPWM) was the basis for the modern PWM strategies applicable to PWM-VSI drives. PWM-VSIs represent the dominant technology in industry today [1][2][3][4][5]. A large number of PWM switching pattern generators have been developed over the past four decades to meet the requirements, mainly, distortion free output waveforms.…”