Selective Harmonic Elimination PWM Control for Cascaded Multilevel Voltage Source Converters: A Generalized Formula

Abstract

This paper proposes a generalized formulation for selective harmonic elimination pulse-width modulation (SHE-PWM) control suitable for high-voltage high-power cascaded multilevel voltage source converters (VSC) with both equal and nonequal dc sources used in constant frequency utility applications. This formulation offers more degrees of freedom for specifying the cost function without any physical changes to the converter circuit, as compared to conventional stepped waveform technique, and hence the performance of the converter is greatly enhanced. The paper utilizes the merits of the hybrid real coded genetic algorithm (HRCGA) in finding the optimal solution to the nonlinear equation system with fast and guaranteed convergence. It is confirmed that multiple independent sets of solutions exist. Different operating points for both five-and seven-level converters including singleand three-phase patterns are documented. Selected experimental results are reported to verify and validate the theoretical and simulation findings.Index Terms-Cascaded multilevel converter, hybrid genetic algorithm, pulse-width modulation (PWM), selective harmonic elimination.

Analysis of strategies of modulation voltage of the active rectifier based on the modular multilevel converters

“…Знак «+» перед функцией угла Θ означает по-вышение уровня напряжения, знак «-», соответст-венно, понижение уровня напряжения на одну ступень. Все углы Θ должны лежать в диапазоне от 0 до π/2, а количество углов коммутации k рав-но ½ от числа подмодулей в плече n. Для трехфаз-ной системы могут быть удалены гармоники не выше 3k -2 (если k -нечетное число) или не выше 3k -1 (если k -четное число) [23].…”

An 11-switch multilevel inverter with a modified space vector modulation

“…To control these inverters, both high and low switching frequency approaches have been applied. For instance, multicarrier PWM strategy [10], space vector modulation [11], and carrier-based space vector modulation [12] fall under high switching frequency approaches, while voltage vector approximation [13] and selected harmonic elimination [14] are examples of low switching frequency methods.…”

Harmonic Minimization in Seven Level Cascaded Multilevel Inverter Using Selective Harmonic Elimination PWM Techniques

“…By utilizing the proposed topology number of switches will decrease altogether and thus the proficiency will improve [5]. In high power applications, the harmonic substance of the yield waveforms must be lessened however much as could be expected keeping in mind the end goal to maintain a strategic distance from bending in the matrix and to achieve the most extreme vitality efficiency [6].…”