To increase the fault tolerance for cascaded H-bridge multilevel inverters (CHMIs) based on level-shifted pulse width modulation (LS-PWM), a modified LS-PWM method is proposed for the inverters operating under faulty conditions. To cover both open- and short-device fault cases, two types of switching scheme are included in this PWM method. With this PWM method, the neutral shift can be applied as fault-tolerant control for CHMIs based on LS-PWM. Finally, three-phase-balanced line-to-line voltages and currents with minimum harmonic distortion are produced for the inverter with disabled power cells. In addition, this LS-PWM method has the capability to improve power distribution among the H-bridge power cells under the faulty conditions. Simulation and experimental results show that the proposed PWM method performs satisfactorily to achieve fault tolerance.

A Modified Level-Shifted PWM Strategy for Fault-Tolerant Cascaded Multilevel Inverters With Improved Power Distribution

Field Programmable Gate Array (FPGA) is a general purpose programmable logic device that can be configured by a customer after manufacturing to perform from a simple logic gate operations to complex systems on chip or even artificial intelligence systems. Scientific publications related to FPGA started in 1992 and, up to now, we found more than 70,000 documents in the two leading scientific databases (Scopus and Clarivative Web of Science). These publications show the vast range of applications based on FPGAs, from the new mechanism that enables the magnetic suspension system for the kilogram redefinition, to the Mars rovers’ navigation systems. This paper reviews the top FPGAs’ applications by a scientometric analysis in ScientoPy, covering publications related to FPGAs from 1992 to 2018. Here we found the top 150 applications that we divided into the following categories: digital control, communication interfaces, networking, computer security, cryptography techniques, machine learning, digital signal processing, image and video processing, big data, computer algorithms and other applications. Also, we present an evolution and trend analysis of the related applications.

Field Programmable Gate Array Applications—A Scientometric Review

Among the renewable energy applications, the most popular inverters are cascaded multilevel inverters. Irrespective of numerous benefits these inverters face reliability issues due to the presence of more circuit components in the design. This has been a critical challenge for researchers in designing inverters with enhanced reliability by reducing the total harmonic distortion (THD). This paper proposes a 31-level asymmetric cascaded multilevel inverter for renewable energy applications. The proposed topology produces waveforms consisting of the staircase with a high number of output levels with lesser components with low THD. The investigations on the feasibility and performance of MLI under steady-state, transient, and dynamic load disturbances. The results are validated from a 1.6kW system which provides the proposed inverter.

/pdf/real-time-implementation-of-a-31-level-asymmetrical-cascaded-4l0bux3352.pdf

Real-Time Implementation of a 31-Level Asymmetrical Cascaded Multilevel Inverter for Dynamic Loads

The Flying Capacitor Multi Level Inverter (FCMLI) has a great advantage with respect to the availability of voltage redundancies. This work proposes a switching pattern for a modified inverter structure. It is used to improve the performance of chosen single phase five level H-bridge type FCMLI as compared to conventional FCMLI. The chosen multi level inverter is simulated for various multicarrier based Pulse Width Modulation(PWM) techniques for a resistive load. The PWM techniques include Phase Disposition (PD) PWM, Phase Opposition and Disposition (POD) PWM, Alternative Opposition and Disposition (APOD) PWM, Carrier Overlapping (CO) PWM, Phase Shift (PS) PWM and Variable Frequency (VF) PWM and the harmonics of the output voltages are observed for various modulation indices. The performance of chosen FCMLI is confirmed through MATLAB-SIMULINK based simulation. It is observed that sinusoidal reference with PODPWM provides output with relatively low distortion. Its also seen that COPWM strategy is found to perform better since it provides relatively higher fundamental RMS output voltage.

/pdf/performance-evaluation-of-multi-carrier-based-pwm-techniques-1imq7j7328.pdf

Performance Evaluation of Multi Carrier Based PWM Techniques for Single Phase Five Level H-Bridge Type FCMLI

Wind power generation has increased in the past twenty years due to the development of power electronic converters. Power generation through wind has advantages over other renewable sources, such as having more efficiency, being pollution-free, and its abundant availability. Power electronic converters play a vital role in the wind energy conversion system. This paper presents a wind-electric system with a permanent magnet synchronous generator, diode rectifier, DC-DC converter (buck-Boost or Cuk converter), and a three-phase five-level inverter. The five-level inverter is a modified form of a cascaded H-bridge inverter that uses a single DC source as an input irrespective of several levels and phases. As the wind speed changes, the Permanent Magnet Synchronous Generator (PMSG) voltage and frequency changes, but for practical applications, these changes should not be allowed; hence, a voltage controller is used that maintains the output voltage of a DC converter, andthus a constant AC output is obtained. The DClink voltage is maintained at the desired voltage by a Proportional plus Integral (PI)-based voltage controller. The DC link voltage fed to the multilevel inverter (MLI) is converted to AC to feed the load. The MLI is controlled with a new Selected Harmonic Elimination (SHE), which decreases the total harmonic distortion (THD). The system is simulated with an Resistive plus Inductive (RL) load and is tested experimentally with the same load;the results prove that the Cuk converter has a better efficiency compared to the Buck-Boost converter, and the system has less THD when compared with the conventional SHE Pulse Width Modulation (PWM) technique.

https://www.mdpi.com/2079-9292/9/6/979/pdf

Combined Harmonic Reduction and DC Voltage Regulation of A Single DC Source Five-Level Multilevel Inverter for Wind Electric System

Multilevel Inverters are becoming popular for their high voltage operating capability for high power applications. This paper presents a comparative study of Cascaded H-Bridge, Neutral Point Clamped and Flying Capacitor multilevel voltage source inverters. These five-level inverters are simulated in MATLAB/ Simulink using multi carrier sine pulse width modulation. FFT analyses of output voltages for an RL load is carried out. The advantages of Cascaded H-Bridge inverter over the other two types of inverters are brought out in this paper.

Comparison of Cascaded H-Bridge, Neutral Point Clamped and Flying Capacitor multilevel inverters using multicarrier PWM

Multi level inverters (MLIs) have been attractive for high power applications. Among the various MLIs, the Cascaded H-Bridge inverter is promising for grid connected wind power and photovoltaic applications. This paper compares three types of MLIs namely the Neutral Point Clamped MLI, the Flying Capacitor MLI, and the Cascaded HBridge MLI. In addition, the Cascaded H-Bridge MLI with a single DC source is presented. These MLIs are simulated in MATLAB using multi-carrier sine pulse width modulation (MCPWM) technique. Simulated output voltages and currents for an RL load are shown for the four configurations and compared based on the total harmonic distortion (THD). Results obtained show the applicability of the Cascaded H-Bridge inverter with a single DC source for grid connected wind power applications.

Seven-level three phase cascaded h-bridge inverter with a single dc source

Predictive Analysis using deep learning techniques are emerging in several engineering domains. Artificial Neural Networks consists of network of layers to learn, process and predict from the data. Their implementation in electrical and electronics engineering has consistently helped in producing intelligent industries with effective results. The brushless direct current (BLDC)motor generates magnetic fields by switching DC current to the motor windings using electronic closed-loop controllers. BLDC motors require low maintenance, and exhibit high speed and sufficient torque capacity and hence are used in various applications. This motor has an edge over other motors because of its superior performance and ease with which the power converters can regulate its speed. This article describes a technique for varying the speed of a BLDC motor that involves altering the voltage of bridge converter, which feeds the motor winding. The speed control is carried out with a speed controller (PI-based). The motor is modelled in MATLAB/Simulink, and a PI controller is employed to provide the speed control. Simulated waveforms of EMF signals are achieved along with rotor speed, Hall Effect signals, electromagnetic torque, and PWMsignals. Artificial neural networks (ANN) are used to forecast the corresponding parameters, and they are fed with the gathered data to produce results that are reasonably close to the results from the simulations. Hence, both the simulation-based approach as well as the predictions from the data provided, yield satisfactory outcomes.

Deep Learning Based Predictive Analysis of BLDC Motor Control

This paper implements Single Phase Matrix Converter (SPMC) in different topologies for various functions such as frequency converter, rectifier, inverter and chopper. A single topology, capable of performing all functions of generalized single phase converter utilizes either AC or DC supply to synthesize the output using Pulse Width Modulation (PWM) techniques. The circuit requires four Common emitter anti-parallel Integrated Gated Bi-polar Transistor (IGBT) with diode pair for bi-directional switching. A safe commutation strategy is facilitated by a switching sequence to avoid voltage spikes on switches. Prior to hardware implementation, simulations were performed to investigate the behavior of SPMC using MATLAB/Simulink.

Modeling and simulation of Single Phase Matrix Converter using PWM

Harmonic elimination at the fundamental frequency is very much appropriate for high and medium range of power generation and applications. This paper considers a new technique for selective harmonic elimination (SHE), in which the total harmonic distortion (THD) is minimized when compared with that of the conventional one. With this technique, the harmonics at lower order are eliminated, which are more predominant than the higher ones.Cascaded H-Bridge inverter fed by a single DC is considered which is simulated with the switching angles generated by both the conventional method of SHE and the new method of SHE. The simulated results of the load voltage and the waveforms of the harmonic analysis are shown. The THD values are compared for the two techniques.  The experimental results are also shown for the new technique. The switching angles are generated with the help of field programmable gated array (FPGA) in the hardware. The value of experimental THD of voltage is compared with that of simulated THD and the comparison prove that the results are satisfactory.

https://ijpeds.iaescore.com/index.php/IJPEDS/article/download/10420/11122

T. Porselvi

Papers

Comparison of Cascaded H-Bridge, Neutral Point Clamped and Flying Capacitor multilevel inverters using multicarrier PWM

Seven-level three phase cascaded h-bridge inverter with a single dc source

Deep Learning Based Predictive Analysis of BLDC Motor Control

Modeling and simulation of Single Phase Matrix Converter using PWM

FPGA Based Selective Harmonic Elimination Technique for Multilevel Inverter