Discrete current control of single-phase cascaded multilevel inverters operating with SHE-PWM

Author(s):  
Fabricio Hoff Dupont ◽  
Junior Romani
Electronics ◽  
2018 ◽  
Vol 7 (7) ◽  
pp. 111 ◽  
Author(s):  
Xingang Fu ◽  
Shuhui Li ◽  
Abdullah Hadi ◽  
Rajab Challoo

A single-phase Cascaded H-Bridge (CHB) grid-tied multilevel inverter is introduced with a detailed discussion of the proposed novel neural controller for better efficiency and power quality in the integration of renewable sources. An LCL (inductor-capacitor-inductor) filter is used in the multilevel inverter system to achieve better harmonic attenuation. The proposed Neural Network (NN) controller performs the inner current control and tracks the references generated from the outer loop to satisfy the requirements of voltage or power control. Two multicarrier-based Pulse Width Modulation (PWM) techniques (phase-shifted modulation and level-shifted modulation) are adopted in the development of the simulation model to drive the multilevel inverter system for the evaluation of the neural control technique. Simulations are carried out to demonstrate the effectiveness and efficient outcomes of the proposed neural network controller for grid-tied multilevel inverters. The advantages of the proposed neural control include a faster response speed and fewer oscillations compared with the conventional Proportional Integral (PI) controller based vector control strategy. In particular, the neural network control technique provides better harmonics reduction ability.


Author(s):  
Yong Yang ◽  
Jianyu Pan ◽  
Huiqing Wen ◽  
Mingdi Fan ◽  
Rong Chen ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3230
Author(s):  
Milovan Majstorovic ◽  
Marco Rivera ◽  
Leposava Ristic ◽  
Patrick Wheeler

The operation of single-phase Modular Multilevel Converter (MMC) is analyzed in the paper. A mathematical model of the converter is developed and described, based on which the structure and selection of parameters for Classical Control and Optimal Switching State Model Predictive Control (OSS-MPC) are defined. Additionally, the procedure for the determination of circuit parameters, such as submodule capacitance and arm inductance, is described and carried out. The listed control methods are designed and evaluated in Virtual Hardware-in-the-Loop together with single-phase MMC power circuit, regarding three control objectives: AC current control, voltage balancing control and circulating current control. Control methods are evaluated for both steady-state and transient performance and compared based on nine criteria: AC current reference tracking, THD of AC current and voltage, submodule capacitor voltage balancing, total submodule voltage control, circulating current magnitude and THD, number of control parameters and computational complexity. This is the first time that a fair comparison between Classical Control and MPC is considered in literature, resulting in superior performance of both control methods regarding four different criteria and the same performance regarding AC current reference tracking.


2021 ◽  
Vol 20 (2) ◽  
pp. 1-7
Author(s):  
Jahanzeb - ◽  
Shahrin Md. Ayob ◽  
Saifullah Khan ◽  
Mohd Zaki Daud ◽  
Razman Ayop

There is always a need to create efficient and optimized converters to deliver the best possible results to achieve a better THD profile in the waveform output. One way is by controlling the switching of the power switches of the converters using appropriate modulation schemes. While numerous works have been done in proposing new switching modulation strategies for multilevel inverters, this work will compare multicarrier PWM and near-to-level control (NLC) modulation schemes. In this paper, multicarrier PWM variants, namely, PD-PWM, POD-PWM, and APOD-PWM, are designed and simulated. Their voltage THD and spectrum performance are discussed when applied to single-phase 7, 9, and 11-level cascaded multilevel inverters. Then NLC modulation will be designed and applied to similar multilevel inverter circuits. It will be shown that the NLC exhibits some superior performances compared to PWM-based but with several drawbacks that can be optimized. 


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