Flying Capacitor Multilevel Inverter Research Articles

An improved modulation technique suitable for a three level flying capacitor multilevel inverter

This research paper introduces an innovative modulation technique for controlling a 3-level flying capacitor multilevel inverter (FCMLI), aiming to streamline the modulation process in contrast to conventional methods. The proposed simplified modulation technique paves the way for more straightforward and efficient control of multilevel inverters, enabling their widespread adoption and integration into modern power electronic systems. Through the amalgamation of sinusoidal pulse width modulation (SPWM) with a high-frequency square wave pulse, this controlling technique attains energy equilibrium across the coupling capacitor. The modulation scheme incorporates a simplified switching pattern and a decreased count of voltage references, thereby simplifying the control algorithm.

Output-feedback control of a grid-connected photovoltaic system based on a multilevel flying-capacitor inverter with power smoothing capability

With the large-scale integration of renewable energy systems, the power inertia and voltage support of the grid are low. Using the inverter with temporary storage capabilities cope with shortages and power fluctuations. This paper presents a new sensorless control of a single-phase grid-connected PV system based on a multilevel flying capacitor inverter MFCI) able to smooth out the power produced. The designed controller involves two cascade loops, an outer loop control extracts the maximum power despite climate change, and an inner loop consists of a model predictive control based on the Lyapunov theory for power factor correction and flying capacitor voltage balancing. Furthermore, an interconnected Kalman-like high-gain observer is combined with the predictive control algorithm to estimate the flying capacitor voltages accurately based on the actual grid current. The stability study of the suggested observer in the closed loop has been described. An algorithm that generates reference signals to manage power flows is also developed. The performance of the proposed controller has been verified on the MATLAB/Simulink platform, and the simulation results confirm the effectiveness of the proposed controller over different grid operating modes.

Enhanced low voltage ride-through control of multilevel flying capacitor inverter based wind generation

This paper introduces a cost-effective control method to enhance the low voltage ride-through (LVRT) capability and smooth the output power of a three-phase multilevel flying capacitor inverter (FCI) in wind turbine-based permanent magnet synchronous generator (PMSG). The proposed approach utilizes the energy storage capability of flying capacitors to mitigate wind power fluctuations and address short-duration outages and deep voltage sags. Additionally, a nonlinear controller based Lyapunov theory is developed to regulate capacitor voltages, improve power factors, and balance DC-link voltage. Numerical simulations are conducted in MATLAB/SimPower systems environment to validate the effectiveness of this comprehensive control strategy across different grid operation scenarios.

Rancang Bangun Multilevel Inverter dengan Filter Pasif L-C-L dan Teknologi IoT Untuk Memantau Perubahan Kecepatan Motor Induksi Satu Fasa

Multilevel inverter is a type of inverter used to generate AC signals with adjustable frequency and better quality. L-C-L passive filter is used to eliminate harmonic distortion in the generated AC signals. Meanwhile, IoT technology is used to remotely monitor and control the speed of the motor through a mobile application. In this thesis, the design of a flying capacitor multilevel inverter is used as an induction motor speed controller with the resulting Total Harmonic Distortion (THD) can be reduced if you add a level to the inverter. Then, L-C-L passive filter is designed to eliminate harmonic distortion in the generated AC signals. Furthermore, the implementation of IoT technology is carried out using Blynk IoT platform. The test results show that the multilevel inverter with L-C-L passive filter successfully generates AC signals with better quality compare without L-C-L passife filter. In addition, IoT technology is successfully implemented and allows users to remotely monitor and control the speed of the motor through a mobile application. Thus, the use of multilevel inverter with L-C-L passive filter and IoT technology can effectively increase the efficiency and control of single-phase induction motor.
 Keywords: multilevel inverter, L-C-L passive filter, IoT, induction motor, total harmonic distortion.

Comparison of Multilevel Inverters with T-type MLI: A Brief Review

This paper gives a comparative analysis of different types of Multilevel Inverters with T-Type inverters. The principal aim of the work is to analyse the T-type multilevel inverter operation with different multilevel inverters such as DiodeClamped Multilevel Inverter, Flying Capacitor Multilevel Inverter and Cascaded H-bridge Multilevel Inverter. All the inverters are compared and their advantages, disadvantages and usages are specified. The inverter used in our work runs on the multilayer bidirectional DC-DC converter. This can be used in Renewable Energy Sources and Electric Vehicle applications. The proposed design includes two power switches with an additional capacitor to balance the currents of the multilayer T-type (MLI) capacitor during an entire drive pattern or fault circumstances. In this design, the big capacitors being electrolytic in T-type Multilevel Inverter has been exchanged with longer-lasting film capacitors due to the highfrequency cycle-by-cycle current security between CN and CP. The converter’s dimensions and weight would be lowered by 20% because of this topology, as the number of switches and the capacitors used for balancing is reduced in this proposed design. The simulation analysis for five-level conventional T-type inverter and proposed T-type inverter with capacitor voltage balancing is done. The line-to-line voltages, line currents, phase voltages, three-phase voltages, and voltage total harmonic distortions are compared for conventional T-type inverter and proposed T-type inverter with capacitor voltage balancing. The simulation results shows that the proposed T-type inverter gives better performance compared to conventional T-type multilevel inverter.

Reduced Common Mode Multilevel Inverter Strategy in Photovoltaic Systems

Now-a-days, non-conventional energy sources are playing a vital role in the generation of electrical energy. This is due to the disadvantages in the conventional sources like pollution, non-availability of the resources, greenhouse effect. Hence more concentration is made by the researcher’s on these non-conventional sources so called as renewable energy sources. These renewable sources are used with the converters along with filters to give the best output. In this work, we are focusing on the renewable energy called solar energy and hence the converter is inverter in this case. Basically we have conventional inverters as well as multilevel inverters. Multilevel inverters are basically classified into three types and they are cascaded H-bridge multilevel inverter, diode clamped multilevel inverter, flying capacitor multilevel inverter. Among these cascaded multilevel inverter as many advantages like reduced number of components. This advantage is being used in this work and is simulated by using MATLAB.

A Lyapunov-Based Model Predictive Control Approach for Photovoltaic Microgrid Integration via Multilevel Flying Capacitor Inverter

In this study, we introduce a Model Predictive Control (MPC) approach based on a Lyapunov energy function, ensuring global asymptotic stability for a single-phase multilevel flying capacitor inverter (FCI) that interfaces with photovoltaic systems and microgrids. The defined cost function is derived from the Lyapunov energy function, harnessing the stored energy within the capacitor and inductor. This choice is rooted in the principle that as long as total energy is continuously dissipated, the system’s states will eventually reach the equilibrium point. Moreover, this cost function eliminates the need for tuning the weighting factors, a process that can be cumbersome and time-consuming due to the lack of clear guidelines. To assess the efficacy of the proposed control strategy, we conducted simulations using MATLAB/Simulink under varying weather conditions. The results obtained demonstrate that the MPC strategy not only ensures overall stability but also delivers high-quality sinusoidal current with minimal total harmonic distortion (THD), practical low steady-state error in the grid current, and rapid dynamic response, even in the face of changing weather conditions.

Switching Sequence Control 31-Level Asymmetric Cascaded of Reduced Switch Count Multilevel Inverter with Multi Carrier Pulse Width Modulation

Various pulse width modulation techniques, including as cascaded multilevel inverters (MLI), diode clamped multilevel inverters, and flying capacitor multilevel inverters, can be used to simply operate common inverters. Due to increased switching losses, current MLIs cannot reach high efficiency. Due to lower losses and THD than standard MLI topologies, the asymmetric cascaded multi-level H-bridge inverter architecture examined in this white paper employs fewer switches and more output voltage levels (Total Harmonic Distortion). The THD is less than the IEEE standard because of the suggested architecture. In this instance, phase difference (PD) multi-carrier PWM techniques are used to control the gate pulses using sinusoidal reference. Each switch receives a different pulse pattern thanks to a method of decimal-to-binary conversion. It is possible to utilise the suggested circuit for applications requiring moderate to high power, and it is quite simple to evaluate. Utilize the MATLAB/SIMULINK environment to simulate time-domain behaviour for the 31-level and 33-level multilevel inverter topologies.

Single Phase Hybrid Cascaded H-Bridge and Flying Capacitor Multilevel Inverter with Capacitor Voltage Balancing

Abstract—In this paper a single-phase hybrid cascaded H- Bridge and Flying capacitor multilevel inverter with capacitor voltage balancing is proposed. Flying capacitor and cascaded H- Bridge multilevel inverters are the two main multilevel inverter topologies. Cascaded H-bridge multilevel inverters require separate DC sources, whereas flying capacitor multilevel inverters contain capacitors that require balancing of their voltages. So, a hybrid-topology inverter, comprising of single- phase five level flying capacitor and five level cascaded H-bridge inverter with their outputs connected in series so as to reduce the total harmonic distortion (THD) is developed. This method gives fast and good control with minimum acceptable amount of harmonics. The proposed system is being simulated in MATLAB/Simulink software. Index Terms— H-bridge, multilevel inverter, Flying capacitor multilevel inverter, Harmonics, Simulink software.

Solar Photovoltaic System-Based Reduced Switch Multilevel Inverter for Improved Power Quality

This paper deals with a reduced switch multi-level inverter for the solar photovoltaic system-based 127-level multi-level inverter. The proposed technique uses the minimum number of switches to achieve the maximum steps in staircase AC output voltage when compared to the flying capacitor multi-level inverter, cascaded type multilevel inverter and diode clamped multi-level inverter. The use of a minimum number of switches decreases the cost of the system. To eliminate the switching losses, in this topology a square wave switch is used instead of pulse width modulation. Thereby the total harmonic distortion (THD) and harmonics have been reduced in the pulsating AC output voltage waveform. The performance of 127-level MLI is compared with 15 level, 31-level and 63-level multilevel inverters. The outcomes of the solar photovoltaic system-based 127-level multi-level inverter have been simulated in a MATLAB R2009b environment.

Flying capacitors multilevel inverter: architecture, control and active balancing

To improve efficiency and productivity of electric energy generators based on photovoltaic, wind or hybrid systems; several DC/AC conversion techniques have been developed and tested like multilevel inverters. Multilevel inverters are a performant solution for the ramp-up of converters. As soon as the DC supply voltage exceeds a few kV, it is necessary to combine switches, switching cells or converters. This paper presents a progressive study of an interesting type of these inverters namely flying capacitor multilevel inverters (FCMLI): architecture, evolutions, benefits and inconvenient. In fact, we processed 3-and 5-level FCMLI while presenting possible circuit schemes and simulation results on Matlab Simulink. Finally, a general formulation has been adopted and applied to a 17 level FCMLI.

A Generalized Phase-Shift PWM Extension for Improved Natural and Active Balancing of Flying Capacitor Multilevel Inverters

The emergence of wide bandgap power devices has brought the attention back to the flying capacitor (FC) multilevel inverters with a large number of stages, in an effort to increase the power density by minimizing the passive components. The main challenge that such systems face, particularly the ones based on high-frequency Gallium-Nitride devices and small-value ceramic capacitors, relate to the stringent requirements for precise and fast capacitor balancing. Conventional <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">natural balancing</i> techniques exhibit poor settling times, while most improved natural balancing methods are not easily scalable to more than five levels. The alternative of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">active balancing</i> normally requires one isolated sensor per FC which increases the overall system cost and footprint, or a single ac-side sensor that is more compact but calls for sophisticated PWMs that again are not available for multiple levels. In this paper we introduce a generalized pulse width modulation (PWM) strategy based on the phase-shift and carrier swapping principles for an arbitrary number of levels. We provide an easy and intuitive method for the extraction of the PWM pattern, the switching states, and their sequence. Simulations were carried out in Matlab/Simulink and experimental tests were conducted on a single-phase 7-level GaN inverter prototype. Not only is the extended PWM advantageous in natural balancing, but it also provides the right zero switching states for ac-side FC sensing in active balancing.

Switching Sequence Control 31-Level Asymmetric Cascaded of Reduced Switch Count Multilevel Inverter with Multi Carrier Pulse Width Modulation

Various pulse width modulation techniques, including as cascaded multilevel inverters (MLI), diode clamped multilevel inverters, and flying capacitor multilevel inverters, can be used to simply operate common inverters. Due to increased switching losses, current MLIs cannot reach high efficiency. Due to lower losses and THD than standard MLI topologies, the asymmetric cascaded multi-level H-bridge inverter architecture examined in this white paper employs fewer switches and more output voltage levels (Total Harmonic Distortion). The THD is less than the IEEE standard because of the suggested architecture. In this instance, phase difference (PD) multi-carrier PWM techniques are used to control the gate pulses using sinusoidal reference. Each switch receives a different pulse pattern thanks to a method of decimal-to-binary conversion. It is possible to utilise the suggested circuit for applications requiring moderate to high power, and it is quite simple to evaluate. Utilize the MATLAB/SIMULINK environment to simulate time-domain behaviour for the 31-level and 33-level multilevel inverter topologies.

Modeling and Control Design Based on Petri Nets Tool for a Serial Three-Phase Five-Level Multicellular Inverter Used as a Shunt Active Power Filter

In this work, we represent a shunt active power filter (SAPF) based on a serial three-phase flying capacitor multilevel inverter (FCMI) controlled by a Petri Nets representation (PNs). This structure is chosen for its significant performances. In fact, the use of the FCMI within the SAPF makes it possible to increase the apparent switching frequency of the structure in order to reduce the value then the volume and weight of the inductance of the output filter. Besides, the FCMI allows the synthesis of a high-voltage signal using low-voltage semiconductor components. Therefore, improving the reliability of this structure leads to the improvement of the dynamics of the SAPF. This paper deals with a new control methodology based on PNs to regulate the flying capacitor voltages and the reference currents issued by the instantaneous active and reactive power theory. Compared to a conventional SAPF composed by a classical two-level inverter and controlled by a simple PWM control, simulation results demonstrate that our proposed control enhances the dynamic system and the power quality by reducing the total harmonic distortion (THD) satisfying the limits of IEEE standards.

Review of reduced‐switch multilevel inverters for electric vehicle applications

AbstractThis paper deals with the detailed review and comparative analysis of latest reduced switch multilevel inverter topologies for electric vehicle applications. The recent trends in reduced‐switch multilevel inverters are discussed. Detailed review of the reduced‐switch multilevel inverter topologies, their merits and demerits, and the comparative analysis based on component count, total harmonic distortion, and efficiency are conducted. This paper gives a detailed review of recent trends in reduced‐switch multilevel inverter topologies for electric vehicle applications. Switching pattern of the topologies is provided for better understanding of the inverter operation. Comparative analysis of the reduced‐switch inverter topologies based on the component count, total harmonic distortion of output voltage, and efficiency is also presented in this paper. Based on the comparative analysis, it is observed that the interleaved nine‐level flying capacitor multilevel inverter topology achieved the lowest output voltage distortion of 1.6%, which is within the acceptable limits of IEEE 519‐2014 standard. It is observed that the three‐level active neutral point clamped multilevel inverter topology achieved the highest working efficiency of 99.4%. This paper discusses the most recent trends in reduced‐switch multilevel inverters. A comprehensive review of the recent publications and a crisp comparative analysis of the different inverter configurations based on component count, harmonic distortion of output voltage, and efficiency are presented in this paper.

Analysis of hybrid switches symmetric flying capacitor multilevel inverter based STATCOM

Static compensator (STATCOM) based on cascaded H-bridge (CHB) multilevel inverter (MLI) uses a lower number of switches compared to the other topologies. Therefore, it is preferred due to lower switch losses. However, it is possible to reduce further the number of switches and its losses in cascaded STATCOM. In this context, a STATCOM based on a cascaded symmetric flying capacitor (SFC) constituted by IGBT and IGCT is presented in this paper. Furthermore, the common issue of imbalance due to asymmetric switch losses has been resolved by proposing and implementing multistage feedback voltage control with a combination of level-shifted and phase-shifted LS-PS PWM switching techniques. Moreover, the switching and conduction power losses calculations and efficiencies of SFC-MLI based on these semiconductors are also presented. Finally, the experimental results show the effectiveness of the proposed topology and the control strategy.

A Review on harmonics elimination in real time for cascaded H-bridge multilevel inverter using particle swarm optimization

Renewable energy has a great importance for power generation as it does not use the fossils fuels. Energy generated from alternative energy sources are weather dependent. To generate a continuous power to meet the load requirements, Battery energy storage system are used. Power conversion process must be much efficient as possible to convert the DC stored energy into AC. This conversion process is usually done by the help of inverters. This paper gives the brief overview on three main categories of multilevel inverter like cascaded h-bridge, neutral point clamped and flying capacitor multilevel inverter and highlights their advantages which can also help the scholars to deeply explore the categories of multilevel inverter. Harmonic elimination is usually done by controlling the switching angles of the inverter. Among all the switching angles techniques, selective harmonic elimination pulse width modulation (SHEPWM) technique is widely used, that has also discussed in this paper. Furthermore, to eliminate the harmonics using SHEPWM, it has the set of nonlinear transcendental equations, these set of equations can be effieceintly solved by the optimization methods. The most efficient and reliable optimization method like particle swarm optimization has been discussed with multiple objective functions in this paper. This paper will help the scholars to understand the finest category of multilevel inverter for harmonic elimination in terms of efficiency and output quality.

Comparison of Multi-Carrier Based Modified SPWM Techniques for Three Level FCMLI

In this paper, a three phase three level flying capacitor multi level inverter is simulated for various multi-carrier based sinusoidal pulse width modulation (PWM) techniques and the result obtained were evaluated. Two type waves named triangular and trapezoidal triangular (TT) waves are used as Carrier waves. Other than normal sinusoidal PWM, Modified sine PWM technique is also used for effective comparison. In Modified SPWM a Sinusoidal wave is used as reference wave and carrier waves conducting for first and last 60° intervals are used as carrier. The Total Harmonic distortion (THD) obtained in various techniques are compared between all the methods. The harmonics, THD, fundamental value of output voltage is observed for various techniques.

Fast online diagnosis of open-circuit switching faults in flying capacitor multilevel inverters

Fast online diagnosis of open-circuit switching faults in flying capacitor multilevel inverters

A New Grid Interactive 11-Level Hybrid Inverter Topology for Medium-Voltage Application

Multilevel inverter (MLI) has wide applications due to its numerous advantages. An improved configuration of eleven-level MLI suitable for medium-voltage range has been proposed in this article. The proposed topology contains two half-bridge submodules, one flying capacitor MLI, and one full bridge submodule. A simple method of capacitor voltage balancing has been demonstrated with less ripple. The study about the effectiveness of proposed MLI has been justified by loss calculation to find the efficiency and voltage ripple analysis of the capacitor. The comparative assessment in terms of switch count, driver count, capacitor requirement, device peak inverse voltage, total standing voltage (TSVp.u), cost function, etc. for the developed hybrid inverter (HI) topology has been presented to establish the utility of the proposed HI. This topology has been checked for its operation under various operating conditions, including frequency and modulation index variation, overmodulation range, and also with motor load. The grid connectivity option of the proposed HI has been verified to ensure the suitability for application with renewable energy sources.