A bidirectional diode containing multilevel inverter topology with reduced switch count and driver

In this paper, a bidirectional diode containing multilevel inverter is introduced to reduce the number of switching elements especially in the case of a high number of output voltage levels. In comparison with classic and recently introduced symmetrical topologies, which are trying to reduce the switch count, this topology has a lower number of semiconductor switches in the same number of output voltage levels. This makes the proposed inverter to be a suitable choice for medium voltage applications like renewable energy applications as well as medium voltage electric drives. Moreover, it can be used in a cascaded configuration for high voltage levels. To depict the performance of the proposed structure, a comprehensive comparison is made between this topology and classic and recently proposed symmetric topologies in terms of switch and gate driver count, power losses, and cost. The performance of the proposed symmetrical 11-level converter is analyzed and simulated in MATLAB/Simulink for both PWM and selective harmonic elimination switching methods. Not only the results are desirable but also the experimental results of laboratory prototype validate the simulation results.     

A new generalized switched diode multilevel inverter topology with reduced switch count and voltage on switches

This article presents a new multilevel inverter topology with reduced power switches. The proposed topology composes of several series connection of basic unit for obtaining a required output voltage level. The proposed topology can operate in symmetric condition. The proposed topology is connected in a cascaded structure to produce a higher number of output voltage levels. The proposed cascaded structure is optimized with the minimum number of components for the maximum number of levels. To prove the superiority of the proposed multilevel inverter topology, different technical parameter comparisons are carried out with recently developed multilevel inverter topologies from the literature. The calculation of total standing voltage is examined for the proposed topology. The operation of the proposed topology is tested and verified for nine-level output voltage. The simulated results are carried out, and it is strengthened by the real-time prototype results.     

基于级联型逆变器的新型PWM技术研究

级联型H桥多电平逆变器的PWM调制技术一般采用载波移相SPWM技术和错时采样SVPWM.对这两种PWM调制技术进行分析,应用一种新型简化多电平PWM技术,即单元矢量延时叠加PWM(Overlap time staggered PWM,OTS-PWM)技术于级联型H桥多电平逆变器.通过对OTS-SPWM和OTS-SVPWM调制技术的的仿真研究,总结了相应的调制规则.最后通过对OTS-SVPWM技术进行实验研究,验证了方案的实用价值.     

基于数学推导的级联型多电平容错逆变器输出性能研究

载波相移SPWM技术应用于级联型多电平逆变器,其载波相移角度差π／N和2π／N两种相移方式,对不同级联数目的逆变器输出有不同影响。当三相逆变器中功率单元发生故障被切除后,输出电压不再平衡．而利用中性点偏移技术,可使逆变器输出线电压重新达到平衡,从而具备较好的容错能力：通过对载波相移PWM技术和中性点偏移原理的数学推导,得出采用载波相移角π/N方式与中性点偏移技术,逆变器输出性能有较大提高的结论。最后对级联型九电平逆变器A相中某一功率单元故障后状况进行仿真实验．验证了数学推导的正确性。     

一种新型移相级联式高压变频器

介绍Diamond-HV移相级联式高压变频器的原理、结构、控制策略、技术性能及现场应用结果。这种高压变频器设计新颖、独特，功率器件少、结构简洁，可靠性高，负荷均衡、线性度好，具有良好的控制特性。移相变压器副边绕组少、制作简单。多电平逆变器能产生多阶梯、低失真电压波形，特别适合于大功率高电压场合。Diamond-HV系列高压变频器输入输出谐波含量低、du／dt小，可直接驱动普通异步电动机．     

基于单元组合的多电平逆变器设计

在研究传统的级联型多电平逆变器的基础上提出了一种多电平逆变器基本构成单元的概念,并从这一概念出发,提出了基于基本构成单元串并、并串思想生成多电平逆变器拓扑的方法.以此方法得到的大量多电平逆变器拓扑,不仅涵盖了已有的基本多电平电路拓扑,而且得到一些新的拓扑结构,从而将多电平变换拓扑统一在基本构成单元的概念之内.为了验证所得到拓扑的正确性,以串一并拓扑为例,进行了仿真和实验验证.这一概念也为多电平逆变器新拓扑的生成提供了思路.     

混合级联型多电平逆变器的研究

提出了一种混合级联型多电平逆变器拓扑结构,给出了逆变器的控制方案。仿真结果表明,逆变器能够以较低的开关频率输出接近于正弦波的电压且只有很低的共模电压。     

链式多电平变换器特定谐波消除脉宽调制方法研究

链式多电平变换器调制方法中,特定谐波消除脉宽调制SHEPWM(SelectedHarmonicElimi-nationPulseWidthModulation)具有输出波形质量高、消除谐波效果好、直流电压利用率高等优点。研究了链式多电平变换器的SHEPWM技术,针对其1/4周期对称的阶梯波形,给出了一种每个H桥开关频率相同的控制方法,同时列出了该方法下的链式多电平变换器的SHEPWM通用非线性超越方程组,重点提出了利用单个H桥的开关角度叠加求取初值的方法。以5电平链式多电平变换器为例,通过Matlab仿真证明了结论的正确性。     

电流型多电平变流器拓扑分析

对电压型和电流型多电平变流器的研究主要集中在拓扑结构和相应的开关控制策略方面.分析了一种新型的单相5电平电流型变流器的拓扑结构.将新拓扑结构和原先的拓扑结构进行比较分析,可以看出新拓扑结构有许多突出的优点,如所需开关器件和均流电感数目少,结构更加简单.在对开关的控制上采用载波位置相反分布型控制策略,控制简单且容易执行.为了使负载输出电流谐波减少,可以通过对输出电平的宽度进行调节,以得到更平滑的负载输出电流.Matlab仿真波形验证了新拓扑结构的正确性和谐波消除法的可行性.     

A reliable and efficient single-phase modular multilevel inverter topology

Bilevel inverters are replaced by multilevel inverters due to their capability of producing quality output voltage with low total harmonic distortion (THD). On the contrary, increase in number of semiconductor switches has questioned the reliability of the multilevel inverter topologies. To enhance the reliability, this paper proposes a single-phase five-level inverter topology with inherent fault-tolerant feature. The proposed inverter can sustain faults in sources and semiconductor switches by amending the switching combinations. No healthy switch is needed to be bypassed during the fault to ensure the optimum utilization of the switches. An analysis on the basis of reliability, cost, and efficiency is carried out of the proposed inverter and compared with the existing topologies. To prove the claim, the experimental results of the developed hardware model is analyzed and compared with the simulation results of MATLAB/SIMULINK.     

一种新型移相级联式高压变频器

采用HV-IGBT元件、作桥级联式的电平逆变技术多重化输出和模块化设计的移相级联式高压变频器．具有结构简洁．安全可靠、无谐波污染等特点．详细介绍了其结构和特点。经试验和实际应用证明．这种高压变频器所用功率器件少．负荷均衡．输入输出线性度好．具有良好的控制特性。     

基于多电平变换逆变电路的拓扑分析

多电平变换逆变电路是一种新的、用于“清洁电力电子装置”的变换电路。本文指出实现多电平变换逆变电路的关键问题之一是电平钳位,并以此为依据将现有的多电平电路拓扑结构进行了分类。文中分析了基于“二极管或电容钳位”和“使用独立直流电源钳位”的两类典型多电平路拓扑结构的优缺点,并在现有的“混合单元多电平逆变电路”单元结构基础上提出了一种新的、使用不同电压比的控制方式。     

New generalized topologies of asymmetric modular multilevel inverter based on six-switch H-bridge

In this paper, for high and low numbers of voltage levels, two new generalized multilevel converters are introduced, which comprise a six-switch H-bridge and several switched-source units. Switched-source units consist of bidirectional and unidirectional switches along with a dc voltage source. The two proposed topologies are compared with topologies based on the six-switch H-bridge, conventional H-bridge, and some new topologies regarding the number of switches, dc voltage sources, gate drivers, and per-unit voltage block on switches. The comparison results reveal the superiority of the proposed topology with low number of voltage level (LNL) and proposed topology with high number of voltage level (HNL) regarding the per-unit voltage block and number of elements, respectively. Thus, the proposed topologies lead to reduction cost and weight of system. Furthermore, for high number of levels, HNL topology is more appropriate than LNL topology and vice versa. The performances of the proposed 15-level LNL and 61-level topologies are simulated by MATLAB, and proposed 15-level LNL topology in producing all voltage levels is validated by experimental results.     

A fault‐tolerant modular multilevel inverter topology

Multilevel inverter topologies have received an increasing importance for their modular structures with better integration of renewable energy sources and reduced filtering requirements. But reliability is compromised in the process of decreasing the number of switches to produce the maximum number of voltage levels. This paper elevates a single‐phase fault‐tolerant inverter topology, which is modular in structure. The proposed inverter is analyzed for open‐ or short‐circuit faults in sources and open‐circuit faults in switches. Sine Pulse Width Modulation with multicarriers technique is used to control the circuit. The carrier signals are reconfigured under fault conditions based on levels to be generated by bypassing the faulted switch or source. The circuit is simulated in MATLAB/SIMULINK, and experimental setup is developed to claim the fault tolerance of proposed inverter.     

阶梯充电自平衡开关电容多电平逆变器

针对传统多电平逆变器功率器件多、结构复杂等缺点,将开关电容技术应用于多电平逆变器拓扑,提出一种可扩展的模块化多电平逆变器.所提逆变器通过开关电容模块中的双电容阶梯充电与串联叠加以及模块的串并联转换,能够以较少的器件输出更多的电平,可以降低逆变器输出电压的谐波畸变率.逆变器不需要额外的电压平衡控制或电压平衡回路即可实现电...     

单元串联多电平中压变频器的研制综述

介绍一种最近研制成功的单元串联多电平中压变频器 ,详细阐述了该装置的原理、结构、控制策略、技术性能以及试验结果 ,介绍了高速浮点型DSP在中压变频调速装置中的软硬件设计思想。试验结果验证了设计方案的正确性和可行性。     

基于载波相移THI-PWM技术的多电平逆变器研究

针对传统的电压型多电平逆变器直流电压利用率低的问题,在对载波相移SPWM调制技术进行数学分析的基础上,将三次谐波注入(Third Harmonic Injection,THI)的思想引入到载波相移技术中,提出了一种适用于多电平逆变器的载波相移THI-PWM调制技术,使得系统的波形系数从1.732上升到2,直流电压利用率提升15%左右。在Matlab/Simulink中搭建了三相五电平逆变器模型进行仿真验证,结果证明了该方法理论的正确性和可行性。     

一种基于开关函数的逆变器新型模型

提出了一种基于开关函数的逆变器新型模型 ,分析了其适用条件 ,并分别对该模型进行仿真和实验研究。研究结果表明该模型具有非常快的仿真速度和较高的精度     

A new structure of single-phase two-stage hybrid transformerless multilevel PV inverter

Transformerless inverters are becoming popular for grid-connected photovoltaic applications due to their simplicity, reduced size, weight, cost, and higher efficiency. In this paper, a two-stage hybrid transformerless multilevel inverter (MLI) for single-phase grid-connected photovoltaic power generation system (PVPGS) is presented. The proposed topology comprises a multilevel boost converter (MLBC) and a symmetrical hybrid MLI. MLBC combines the boosting and switched capacitor voltage functions to produce self-balanced multiple voltage levels. The proposed MLI is derived from a combination of bidirectional switches, a half bridge, and a diode-clamped branch, which can produce only two variations in the total common mode voltage and is capable of suppressing leakage current as per DIN VDE 0126-1-1 grid standards. It offers the advantages of scalability, reactive power capability, reduced total harmonic distortion, and filter size. The proposed hybrid transformerless seven-level inverter is simulated in MATLAB, and experimental setup is built to validate the effectiveness of the proposed configuration. Finally, a comprehensive comparison is made with other seven-level inverter topologies.     

Experimental verification of a hybrid multilevel inverter with voltage-boosting ability

A new nine-level natural-balanced boost hybrid multilevel inverter (BH-MLI) is proposed in this paper. Each phase of the proposed BH-MLI is designed with only 11 semiconductor switches and two electrolytic capacitors. Here, the capacitor voltages are balanced by utilizing the series-parallel and natural balancing techniques effectively. Furthermore, the proposed circuit eradicates the multiple DC sources by introducing a single DC link for single- and three-phase applications. The proposed topology can be easily extendible to obtain higher level output voltage waveform due to its modular-switched capacitor cells (SCCs). Besides, the higher voltage level generation does not pose high-voltage stress on any of the topology components, as the blocking voltage of all devices within the source voltage magnitude. Further, a quantitative comparison is conducted among the state-of-art switched-capacitor multilevel inverter (SC-MLIs) to highlight the superiority of the proposed configuration. Finally, the performance of the proposed BH-MLI is experimentally validated with phase disposition-pulse width modulation (PD-PWM) and round control method at different modulation indices, load conditions.