Low-order harmonics control in staircase waveform useful in high-power application by a novel technique

Abstract

Summary Few switching transition in high‐power and medium‐voltage application of power converters is desirable. The optimal pulse‐width modulation (OPWM) at fundamental switching frequency offers a better quality waveform at lower switching losses. It is a preprogrammed modulation technique where certain amounts of lower order harmonics are controlled and fundamental voltage is maintained. Here, a set of nonlinear transcendental equations is obtained, which exhibits multiple, unique, or no solution in different range of modulation index (MI). This paper proposes an advanced and fast method to obtain switching instants for OPWM equations. Moreover, it can solve a large number of such equations as computation of Jacobian matrix in the subsequent iteration is estimated from the previous values. Moreover, the proposed method also removes the singularity problem especially for large OPWM equations. The computational, simulation, and hardware results are provided to validate the concept for various cases.

Low switching frequency modulation of a 3 × 3 matrix converter in UPFC application using differential evolution method

“…Since the system of equation represented by (39) can give a variety of solutions such as multiple, unique, or no solution in different ranges of modulation, a number of methods can be used to solve these equations. [22][23][24][25][26][27][28][29][30] The solutions are normally calculated offline and then stored into lookup table and are implemented in various applications for different operating conditions. In this paper, the solutions are obtained using an evolutionary-based differential evaluation (DE) technique, which includes the benefits of GA and PSO techniques.…”

“…Since the system of equation represented by (39) can give a variety of solutions such as multiple, unique, or no solution in different ranges of modulation, a number of methods can be used to solve these equations 22‐30 . The solutions are normally calculated offline and then stored into lookup table and are implemented in various applications for different operating conditions.…”

“…The high switching loss decreases the efficiency of the system and reduces the reliability of the whole system. Various optimization techniques are proposed in the literature to solve electrical engineering problems that are diverse in nature 22‐24 . For VSCs, the harmonics control governing equations are nonlinear transcendental by nature and therefore will provide unique, multiple, or no solutions in different modulation index or operating points.…”

“…Various optimization techniques are proposed in the literature to solve electrical engineering problems that are diverse in nature. [22][23][24] For VSCs, the harmonics control governing equations are nonlinear transcendental by nature and therefore will provide unique, multiple, or no solutions in different modulation index or operating points. In literature, various methods are proposed to obtain solutions for these equations.…”

An improved SHM‐PWM scheme for three‐phase seven‐level CHB inverter to improve power quality by fulfilling CIGRE WG 36‐05 and EN 50160 and sharing equal power between the H‐bridge cells

“…In literature, several modulation schemes have been proposed for controlling the output voltage waveform quality of multilevel inverters. These can be listed as sinusoidal pulse width modulation (SPWM), space vector modulation, selective harmonic elimination (SHE)‐pulse width modulation (PWM), optimal minimization of THD (OMTHD), optimal PWM (OPWM), and selective harmonic mitigation‐(SHM) PWM . Out of these PWM schemes, SHE‐PWM scheme works on the low‐switching frequency, and it is used to completely eliminate (E‐1) number of specific low‐order harmonics of the output voltage using “E” number of switching instances in each quarter cycle of the output waveform.…”