Active voltage balancing strategy of asymmetric stacked multilevel inverter (original) (raw)
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A Review on Voltage Balancing Solutions in Multilevel Inverters
Indonesian Journal of Electrical Engineering and Computer Science, 2015
Multilevel inverters are used in high power and medium voltage applications. Employing multilevel inverter with renewable energy alone, the voltage balance cannot be made because the number of level increases in multilevel inverter the control gets complexity. So voltage imbalance problems are introduced. The voltage imbalance problems can be classified into two types; Midpoint unbalance and the central capacitor discharge. These problems can be solved by using voltage balancing solutions. The solutions are hardware based; software based, and combined solutions. By using these types of solutions the voltage balancing problems can be solved and the efficiency of multilevel inverter could be high. This paper reviews about various voltage balancing solutions in multilevel inverter.
A Five Level SC Inverter with reduced switch count and self balancing capability
El-Cezeri Fen ve Mühendislik Dergisi
Multilevel inverters (MLIs) have become a favoured option for medium voltage and high power DC to AC conversion applications to assure high power level cascade type inverter which accepts multiple/single DC sources and offers combined AC output for appropriate voltage and frequency. MLIs provide various benefits over two-level inverters, including lower dv/dt, the capacity to handle greater voltage levels, a quasi-sinusoidal output waveform, and lower Total Harmonic Distortion (THD), among others. The biggest problem in adopting the MLI is the increasing number of switches and it's design. MLIs based on switched capacitors (SC) for boost-type DC-AC converters often demonstrate a trade-off among switch voltage rating and switch count. This work introduces a new 5-level(5L) SC inverter by adding a switched capacitor module into the usual 3L neutral point clamped inverter leg(NPC). The SC unit consists of one bidirectional switch and two capacitors capable of withstanding one-quart...
Journal of Power Electronics, 2017
This paper presents a new cascaded asymmetrical single phase multilevel converter with a reduced number of isolated DC sources and power semiconductor switches. The proposed inverter has only two H-bridges connected in cascade, one switching at a high frequency and the other switching at a low frequency. The Low Switching Frequency Inverter (LSFI) generates seven levels whereas the High Switching Frequency Inverter (HSFI) generates only two levels. This paper also presents a solution to the capacitor balancing issues of the LSFI. The proposed inverter has lot of advantages such as reductions in the number of DC sources, switching losses, power electronic devices, size and cost. The proposed inverter with a capacitor voltage balancing algorithm is simulated using MATLAB/SIMULINK. The switching logic of the proposed inverter with a capacitor voltage balancing algorithm is developed using a FPGA SPATRAN 3A DSP board. A laboratory prototype is built to validate the simulation results.
A Generalized Multilevel Inverter Topology with Self Voltage Balancing
Multilevel power converters that provide more than two levels of voltage to achieve smoother and less distorted ac-to-dc, dc-to-ac, and dc-to-dc power conversion, have attracted many contributors. This paper presents a generalized multilevel inverter (converter) topology with self voltage balancing. The existing multilevel inverters such as diode-clamped and capacitor-clamped multilevel inverters can be derived from the generalized inverter topology. Moreover, the generalized multilevel inverter topology provides a true multilevel structure that can balance each dc voltage level automatically without any assistance from other circuits, thus, in principle, providing a complete and true multilevel topology that embraces the existing multilevel inverters. From this generalized multilevel inverter topology, several new multilevel inverter structures can be derived. Some application examples of the generalized multilevel converter will be given.
Multilevel inverters with less number of components and power supplies play important role in most of power electronic applications. In this paper, a new switched capacitor multilevel inverter (SCMLI) is presented which can generate more output voltage levels with less number of components and one required dc power supply in contrast to some of existing topologies. This structure uses a new switched capacitor converter (SCC) which includes several capacitors that can be charged by binary asymmetrically algorithm as self-balancing. At the next, proposed SCMLI is connected to another SCMLI unit as hybrid form and then, the output voltage levels are increased with good quality using hybrid modulation technique. Several simulation results by PSCAD/EMTDC software and comparisons in different aspects such as number of required switches, capacitors, number of components that are in current path and total blocked voltage is given to confirm the effectiveness of proposed topology.
A new topology of multilevel inverter with switches count reducing at symmetrical/asymmetrical mode
Indonesian Journal of Electrical Engineering and Computer Science, 2022
The multi-level inverter (MLI) has an important role in modern technologies due to its advantages. On the other hand, its circuits need a large number of switches, capacitors and direct current (DC) sources. This paper introduces a new topology for a MLI with a reduction in number of switches, no need for capacitors in exchange for an increase in number of levels in the output. The proposed model is operated in symmetric and asymmetric modes with the presence of resistive and inductive loads. Whereas, (5 and 9) output levels were obtained in symmetric and asymmetric modes, respectively. In contrast, the number of switches was halved and without need for capacitors, compared to the conventional MLI topologies not a secret that reducing the number of switches has the effect of reducing cost and complexity, in addition to the problems of balancing the voltage on capacitors. The programming environment used to build the proposed model of the MLI was MATLAB/Simulink, where the validity of the hypotheses contained in this paper were proved and the obtained results are identical to what was planned under different loads and different operation modes. In addition, the paper included a comparison study among the proposed topology and conventional topologies in terms of the number of switches, capacitors and sources.
Multilevel Inverter Topology with Self-Balancing Voltage and Modularity in Design
International Journal for Research in Applied Science and Engineering Technology IJRASET, 2020
Multilevel inverters have already gained high popularity among research teams as well as in production of high and medium-voltage applications for industrial purposes over the period of twenty years. Moreover, multilevel inverters are able to generate switched waveforms with reduced levels of harmonic sag compared to a conventional converter. Recent increased interest in multilevel inverters is due to their ability to generate high quality output waveforms at lower switching frequencies; the multilevel topology used in dynamic voltage restorer works towards the reduction of the total harmonic distortion counting all of the losses at the output end. This paper provides a new topology for the modulation in the multilevel inverter using switched capacitor. The self-balancing capability for the capacitor voltage and the SC connected in parallel so as to provide the voltage setup. The methodology presented works towards minimizing the THD by implementing the 9 level MLI and comparing the same to the other level in terms of distortion. The factors like cost are also considered in the design for which half bridge is being used.
This paper presents a new family of cascaded multilevel inverters (CMLIs) which can generate a considerable number of output voltage levels with minimum number of required accompanying switching devices. Conceptually, each stage of proposed CMLI is composed of using a novel capacitor-based unit including two floating capacitors, one embedded dc voltage source and three power switches. In this case, the balanced voltage of integrated capacitors can be precisely provided as self-voltage balancing without using any auxiliary circuits, close loop systems and intricate modulation techniques. In addition, to reach different number of output voltage levels, four different algorithms pertaining to the symmetrical, binary asymmetrical, trinary asymmetrical and also hybrid patterns for determining the magnitude of isolated dc voltage sources are presented. Hereby, proposed hybrid structure is capable of working under mixed switching frequency without aiming the conventional full H-Bridge cell. Therefore, a high quality of output waveforms with reduced switching devices as well as power loss dissipation can be alternatively achieved. To confirm the validity of proposed CMLI, a complete comparison with several recently presented topologies besides several simulation and experimental results based on trinary asymmetrical and hybrid evolved structures will be also given.
Review on Single-DC-Source Multilevel Inverters: Voltage Balancing and Control Techniques
IEEE Open Journal of the Industrial Electronics Society
Nowadays, single-dc-source multilevel inverter (SDCS-MLI) topologies are being considered as more suitable for many power system applications such as renewable energy conversion systems and electrified transportations compared to the multiple-dc-source MLIs. Voltage balancing of the auxiliary capacitors in those configurations is a major matter of concern. Different techniques have been developed to overcome this issue that can be mainly categorized as internal controller-based and external controller-based techniques. In the former techniques, the redundant switching states help balancing the capacitors voltages. On the other hand, the latter techniques involve external regulators to balance the capacitors' voltages. This article analyzes most of the existing techniques to control and balance the capacitors voltages in SDCS-MLIs, such as pulsewidth modulation, space vector modulation (SVM), hysteresis control, model predictive control, sliding mode, and artificial intelligence based control techniques. Furthermore, a comprehensive comparison is presented to illustrate the advantages/disadvantages of each technique. Finally, some industrial challenges and future works are projected. INDEX TERMS Control techniques, modulation techniques, multilevel inverters, single dc-source, singledc-source multilevel inverter (SDCS-MLI), voltage balancing.
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 Diode-Clamped 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.