Five-level Cascaded H-bridge Multilevel Inverter Research Articles

Prediction Errors Analysis and Correction on FCS-MPC for the Cascaded H-Bridge Multilevel Inverter

Predictive errors restrict high performance of finite control set model predictive control (FCS-MPC) in the cascaded H-bridge multilevel inverter.In order to solve this problem, the influence mechanisms of parameter mismatch, model discretization, and sampling error on voltage and current prediction errors are analyzed in this article. A hierarchical multifactorial error correction method is proposed. The known voltage prediction errors of the previous adjacent prediction periods are first fed back to calculate the voltage predictive error factors and self-correct the next voltage prediction errors. And then the current prediction errors are calibrated by the corrected voltage and the calculated current predictive error factor. This proposed method involves a simple structure and a good inhibitory ability on multifactorial prediction errors. Finally, experimental results in a three-phase five-level cascaded H-bridge multilevel inverter support the theoretical analysis and the proposed method.

Fault Recognition and Reconfiguration for Three-Phase Five-level Cascaded H-bridge Multilevel Inverter

Fault Recognition and Reconfiguration for Three-Phase Five-level Cascaded H-bridge Multilevel Inverter

Open Circuit Fault Diagnosis in Five-Level Cascaded H-Bridge Inverter

The development of power electronic converter, especially multilevel converter, is remarkable for several decades. The complex switching and increased power of semiconductor devices are prime reasons for faults in multilevel inverters and have raised question about reliability. To improve the reliability, a cost-effective solution in terms of fault diagnosis is essential. In this context, this study proposed an open circuit fault (OCF) diagnosis technique for a switching device in a five-level cascaded H-bridge multilevel inverter using fuzzy logic control. The OCF features like output voltage total harmonic distortion (THD) and normalized average output voltage are fuzzed as input variables of the fuzzy logic controller. These input variables are divided into various triangular antecedent membership function (MF). The output produced by the fuzzy controller as consequent MFs is divided into different levels to identify the faulty switch. In order to make a complete fault-tolerant structure, a reduced modulation index-based postfault control is suggested to get a balanced output voltage. The MATLAB/Simulink results and prototype results are the evidence to support the proposed fault diagnosis technique.

Modified PWM Technique for a Multi-Pulse Converter Fed Multilevel Inverter Based IM Drive

This article presents a 36-pulse converter and five-level cascaded H-bridge multilevel inverter (CHB-MLI) fed medium voltage induction motor drive (MVIMD) system. The multiwinding transformer (MWT) for a 36-pulse ac–dc converter is designed in such a way that it requires the least number of windings and enhances power quality at the grid end. This is helpful to reduce the size, weight, and cost of the presented MVIMD. The modified carrier level shifted pulsewidth modulation (MC-LSPWM) is used to control five-level CHB-MLI fed induction motor, which adheres the power quality standard IEEE519 at drive end. The main characteristic of used PWM is that it has inherent rotating switching pattern nature, which is helpful to enhance the power quality performance and to decrease the continuous conduction time of the H-bridge. Whereas, this continuous conduction among H-bridges, is not balanced in the level-shifted pulsewidth modulation (LSPWM). Therefore, conduction losses among the H-bridges of CHB-MLI are balanced and reduced by this MC-LSPWM for continuous operation, which is not possible with the conventional LSPWM. The practicality of this MVIMD with an indirect field-oriented control and MC-LSPWM technique, is substantiated via a comparison with the configuration reported in the literature, simulation, and experimentation, respectively. Performance of the drive system is evaluated during different operating conditions, such as starting, steady-state, speed and load perturbations. Further, a detailed comparative analysis of results is presented, which demonstrates that presented MWT configuration has fewer number of windings (only thirty-three windings), less conductor material and minimum losses. Thus, the presented configuration of MVIMD shows excellent performance characteristics with reduced size and weight such as currents total harmonic distortion is 2.5% (grid end), 3.66% (drive end) and efficiency of the drive is 88.101%, when the drive runs at rated conditions.

Datasheet-Driven Compact Model of Silicon Carbide Power MOSFET Including Third-Quadrant Behavior

This article presents a simulation model of silicon carbide (SiC) power MOSFET that accurately predicts both the static and dynamic third-quadrant behavior without compromising the first-quadrant's accuracy. Unlike existing models, this model features an asymmetric third-quadrant behavior for MOSFET characteristics necessary for the accurate synchronous rectifier simulations. Moreover, it includes the gate-dependent body diode behavior, essential for the accurate prediction of freewheeling high-side device behavior in half-bridge configurations with significant gate voltage oscillation. The model also includes reverse recovery characteristics for the accurate overshoot and power loss prediction. Despite having these added features, the model demonstrates good convergence and efficiency due to the replacement of conditional piecewise equations with continuous ones consisting of weighted variables. The model's convergence capability and efficiency have been verified by simulating a five-level cascaded H-bridge multilevel inverter. The model's superior efficiency and accuracy have been validated by comparing it with an established SiC power MOSFET model. Also, an easy-to-follow parameter extraction procedure is documented that only requires data commonly available in commercial datasheets for broader utility. Considering accuracy, efficiency, and convenience, the model is useful for all power electronics converter applications.

Optimized Modeling and Control Strategy of the Single-Phase Photovoltaic Grid-Connected Cascaded H-bridge Multilevel Inverter

This paper presents the modeling and control-loop design method with an inverted decoupling scheme of a single-phase photovoltaic grid-connected five-level cascaded H-bridge multilevel inverter. For the unity power factor, the proportional and integral current controller with a duty ratio feed-forward compensation is used. In addition, in order to achieve the maximum power point tracking of each photovoltaic array, when the stacked modules are in the partial shading condition, each direct current (DC) voltage is stably controlled to their maximum power points (MPP) by dedicated voltage controllers of each H-bridge module. This paper also presents a control method that minimizes the effect of the loop-interaction in the design of an individual DC-link voltage control loop in a two-input two-output system. The proposed control methods of the cascaded H-bridge multilevel inverter are validated through the simulation and experimental results of the 2-kW prototype hardware.

A Novel Computational Approach for Harmonic Mitigation in PV Systems with Single-Phase Five-Level CHBMI

In this paper, a novel approach to low order harmonic mitigation in fundamental switching frequency modulation is proposed for high power photovoltaic (PV) applications, without trying to solve the cumbersome non-linear transcendental equations. The proposed method allows for mitigation of the first-five harmonics (third, fifth, seventh, ninth, and eleventh harmonics), to reduce the complexity of the required procedure and to allocate few computational resource in the Field Programmable Gate Array (FPGA) based control board. Therefore, the voltage waveform taken into account is different respect traditional voltage waveform. The same concept, known as “voltage cancelation”, used for single-phase cascaded H-bridge inverters, has been applied at a single-phase five-level cascaded H-bridge multilevel inverter (CHBMI). Through a very basic methodology, the polynomial equations that drive the control angles were detected for a single-phase five-level CHBMI. The acquired polynomial equations were implemented in a digital system to real-time operation. The paper presents the preliminary analysis in simulation environment and its experimental validation.

Improved Output Voltage Quality using Space Vector Modulation for Multilevel Inverters

Space vector modulation (SVM) has received wide acceptance due to many benefits over other techniques such as higher output voltages, lower total harmonic distortion (THD), high-efficiency and flexible to be implemented in vector control systems. In digital implementation, the SVM equations can be optimally computed by eliminate the use of complex forms. In this paper, the simple SVM based on twolevel inverter is employed for higher levels of inverters. This is to retain the simplicity of SVM computation for three-level and five-level cascaded H-bridge multilevel inverter (CHMI). Moreover, the proposed method utilizes two controller boards to perform high computational workloads and to eliminate glitch and error problems. Experiment results show that the THD of output voltage in five-level CHMI gives the smallest value among the results obtained from other levels.

DSPACE implementation of cascaded H-bridge inverter for harmonics minimization using artificial-intelligence

Purpose – The active power filter with two-level inverter needs a high-rating coupling transformer for high-power applications. This complicates the control and system becomes bulky and expensive. The purpose of this paper is to motivate the use of multilevel inverter as harmonic filter, which eliminates the coupling transformer and allows direct control of the power circuit. The advancement in artificial intelligence (AI) for computation is explored for controller design. Design/methodology/approach – The proposed scheme has a five-level cascaded H-bridge multilevel inverter (CHBMLI) as a harmonic filter. The control scheme includes one neural network controller and two fuzzy logic-based controllers for harmonic extraction, dc capacitor voltage balancing, and compensating current adjustment, respectively. The topology is modeled in MATLAB/SIMULINK and implemented using dSPACE DS1103 interface for experimentation. Findings – The exhaustive simulation and experimental results demonstrate the robustness and effectiveness of the proposed topology and controllers for harmonic minimization for RL/RC load and change in load. The comparison between traditional PI controller and proposed AI-based controller is presented. It indicates that the AI-based controller is fast, dynamic, and adaptive to accommodate the changes in load. The total harmonic distortion obtained by applying AI-based controllers are well within the IEEE519 std. limits. Originality/value – The simulation of high-power, medium-voltage system is presented and a downscaled prototype is designed and developed for implementation. The laboratory module of CHBMLI-based harmonic filter and AI-based controllers modeled in SIMULINK is executed using dSPACE DS1103 interface through real time workshop.

Optimized switching scheme of cascaded H-bridge multilevel inverter using PSO

Abstract The paper uses particle swarm optimization (PSO) to determine the optimum switching angles of cascaded H-bridge multilevel inverter (CH-MLI) so as to produce the required fundamental voltage and reduce the harmonic content. This is done by solving the transcendental equations characterizing the harmonic content. The validity of the proposed method is verified through simulation studies for three-phase, five-level CH-MLI. To compare the results obtained using PSO, the simulation studies have been extended for three-phase, five-level CH-MLI using sinusoidal pulse width modulation (SPWM). The results obtained using PSO are found superior as compared to SPWM in terms of total harmonic distortion at different modulation indices.

Diagnosis of Faults due to Misfiring of Switches of a Cascaded H-Bridge Multi-level Inverter using Artificial Neural Networks

This paper presents an artificial neural network based fault identification system for a five-level cascaded H-Bridge multilevel inverter (MLI). A Radial Basis Function (RBF) neural network is trained using radial basis functiontraining algorithm to identify the location of the switch that is misfired at an instant prior to its actual firing time.The proposed fault diagnostic system identifies the fault with a greater accuracy and the results to various input patterns are presented in a tabular format for easy comprehension.