一种用于三电平逆变器的SVPWM调制方法研究

本文从二极管箝位型三电平逆变器的基本结构出发，分析其输出状态，推导出六角形空间电压矢量图。然后从一种改进的，可以减小开关损耗，避免高的dv／dt三电平空间矢量PWM调制策略出发，建立了基于Matlab的详细仿真方案，验证了方案的可行性。文章给出了扇区判断的算法流程图，脉冲生成模块的内部结构图，其中的扇区判断的算法和脉冲生成方法对于用DSP实现三电平SVPWM具有重要的参考价值。     

基于矢量合成的三电平PWM整流器脉宽调制技术的研究

介绍了二极管中点箝位型三电平PWM整流器电路的拓扑结构和传统的空间矢量脉宽调制(SVPWM)的基本原理。分析了一种小矢量合成虚拟空间矢量的三电平SVPWM脉宽调制方法,并把它与基于冗余小矢量的中点电位滞环控制策略相结合,从而更好的控制中点电位的波动。为避免参考电压矢量在扇区切换中输出矢量突变,采用了一种首发矢量全部采用正小矢量或负小矢量的空间矢量调制算法。最后把调制策略应用到三电平整流器中进行仿真分析,仿真结果验证了调制策略的正确性和有效性。     

基于KL坐标系三电平SVPWM算法的仿真研究

传统三电平SVPWM算法复杂,根本原因是采用直角坐标系,判断参考矢量所落八的扇区等,需要大量的三角函数计算。针对于多电平SVPWM,在此指出了坐标系选取不当是造成计算复杂的根本原因。采用KL坐标系,空间矢量的合成仅含有乘法和加法运算,运算量的大小与电平数无关。仿真验证说明了算法可行且简单有效,避免了大量三角函数的运算。可以应用到三电平及多电平SVPWM算法中。     

一种优化三电平逆变器的SVPWM算法的研究

针对传统SVPWM算法计算复杂的缺点,提出一种基于60°坐标下三电平逆变器SVPWM调制算法的控制策略。该控制策略可大幅简化传统SVPWM算法参考矢量扇区判定及开关矢量作用时间的运算,通过在g-h非正交坐标系内对大小扇区规则判断、基本矢量作用时间计算和作用顺序方法进行了研究,减小了控制器的计算工作量。采用Matlab/Simulink仿真软件对该控制策略进行了仿真,仿真结果验证了该控制策略的正确性及有效性。     

基于TMS320F240的三电平逆变器SVPWM实现

在两电平的常规空间矢量PWM算法的基础上，给出了三电平空间矢量PWM算法，并提出一种改进的三电平空间矢量PWM调制策略来进行二极管钳位型三电平逆变器的控制，从而实现最小开关损耗。基于TMS320F240 USP实现了三电平逆变系统的数字控制，实验结果论证了该方案的可行性。     

多电平逆变器通用简化空间矢量调制法

空间矢量调制法在多电平逆变器中已得到广泛使用,然而传统SVPWM算法需要扇区判断和繁琐的三角函数运算,且所有的基本电压矢量必须预先计算并储存起来供后续运算调用,这样既增加了控制器的计算量,影响响应速度,又占用了一定的存储空间。此外,随着电平数的增加,算法会越来越复杂。为此,提出了一种通用的简化空间矢量调制法,在定位了参考电压矢量后,基于两个表格进行简单的逻辑运算即可得到所需的开关状态和开关顺序,且该算法适用于更高电平的逆变器。最后,搭建了三电平NPC逆变器和五电平NPC/H桥逆变器的MATLAB仿真模型,并对三电平NPC逆变器做了实验研究,仿真和实验结果验证了该算法的有效性和通用性。     

载波相移技术在H桥级联多电平STATCOM中的应用

本文介绍了载波相移技术包括载波相移正弦脉宽调制（CPS-8PWM）和错时采样空间矢量调制（STS—SVM）的基本原理,提出了载波相移正弦脉宽调制和错时采样空间矢量调制在H桥级联多电平STATCOM中的实现方法,并进行了仿真验证。仿真结果表明,基于载波相移正弦脉宽调制和错时采样空间矢量调制的H桥级联多电平STATCOM能...     

NPC逆变器SVPWM的区间计算和开关序列输出优化

多电平逆变器拓扑实际应用中,常规的空间矢量脉宽调制（SVPWM）算法需进行大量的三角函数运算和复杂的扇区逻辑判断,开关序列产生繁琐,输出偶次谐波严重。为解决这些问题,提出一种优化算法。通过坐标变换归一化处理和扇区旋转减少计算,采用开关序列再生机理简化序列产生机制。仿真结果表明,运用该方法后,运算量至少减小50%,开关序列产生快速,输出电压无偶次谐波,三次谐波以及三的倍数次谐波。     

60°转360°电压空间的SVPWM软件算法

提出了一种电压空间矢量调制的新型软件算法,在该算法中无须进行电压矢量夹角的三角函数运算及扇区判断,只需定义60°电压空间内的矢量运算公式,由程序自动将360°的电压空间矢量运算转化为60°的电压空间矢量运算,该方法简单,容易实现,为CPU节约了大量的空间资源,文章最后给出了其在交流异步电机控制上的实验波形与结果。     

基于DSP的三电平逆变器SVPWH调制研究

本文介绍二极管箱位式三电平电压空间矢量脉宽控制的基本原理和实现方法：重点分析一种易于DSP实现的三电平PWM整流器空间矢量脉宽调制优化算法,该算法只需进行简单的坐标变换,再经过普通的算术运算即可计算出各基本矢量的作用时间。以TMS340F2812为控制平台,DSP主要实现系统的初始化和脉冲输出功能,最后用matlab／simulink仿真验证给出实验结果,证明了方案的正确性。     

Space Vector Modulation Applied to Three-Phase Three-Switch Two-Level Unidirectional PWM Rectifier

This work presents a methodology to apply space vector modulation to a three-phase three-switch two-level Y-connected unidirectional pulsewidth modulation (PWM) rectifier. Converter switching stages are analyzed to determine switch control signals for space vector modulation. A switching sequence is proposed in order to minimize the number of switch commutations and to reduce the switching losses. Duty cycle functions are determined and the desired switching sequences are performed by a simple PWM modulator with no need of to determine the present sector of vector. For this propose is just necessary to impose the desired current sectors from input voltage references. The vector control structure used with the proposed modulation technique is also described. In order to validate the proposed modulation technique, experimental results are presented for a 20 kW prototype.     

A General Space Vector PWM Algorithm for Multilevel Inverters, Including Operation in Overmodulation Range

This paper proposes a simple space vector pulsewidth modulation algorithm for a multilevel inverter for operation in the overmodulation range. The proposed scheme easily determines the location of the reference vector and calculates on-times. It uses a simple mapping to generate gating signals for the inverter. A five-level cascaded inverter is used to explain the scheme. The scheme can be easily extended to a n-level inverter. It is applicable to neutral point clamped topology as well. Experimental results are provided for five-level and seven-level cascaded inverters     

Space Vector Modulation for Two-Level Unidirectional PWM Rectifiers

This paper presents the concepts for application of space vector modulation to two-level unidirectional pulsewidth modulation (PWM) rectifiers, and a methodology for the use of this modulation is proposed and applied in three different groups of rectifiers. For each group of rectifiers, the converter switching stages are analyzed to determine switch control signals for space vector modulation. One switching sequence is proposed for all rectifiers in order to minimize the number of switch commutations and reduce the switching losses. Duty cycle functions are determined, and the desired switching sequences are performed by a simple PWM, without the need to determine the present sector of the vector. For this purpose, it is necessary to impose the desired current sectors from input voltage references only. In order to validate the proposed modulation techniques, simulation and experimental results are presented for a 20-kW prototype.      

基于电压空间矢量的三相PWM整流器控制研究

首先建立了三相电压型PWM整流器的数学模型，并对其矢量控制策略进行了分析，在此基础上提出了一种简单的电压空间矢量算法，该算法根据参考电压矢量在坐标系上的分量直接计算电压空间矢量在各个扇区内的作用时间，实验结果验证了所提出控制算法的可行性。     

A 3-D generalized direct PWM algorithm for multilevel converters

A three-dimensional (3-D) generalized direct pulse width modulation (PWM) algorithm is proposed for multilevel converters in a three-phase, four-wire system. It is proved to be equivalent to the newly proposed generalized 3-D space vector modulation (SVM). However, the direct PWM greatly simplifies the calculation process and is much easier to implement in digital controllers. The direct PWM can be used in all applications needing a 3-D control vector, such as active filters, uninterruptible power supplies, etc. Simulation and experimental results are given to show the validity of the proposed control strategy.     

Program-controlled soft switching PRDCL inverter with new space vector PWM algorithm

A soft switched space vector PWM inverter is developed using new parallel resonant DC-link (PRDCL). This PRDCL can operate on variable DC-link pulse position and width resulting in enhanced PWM capability, which is superior to other resonant DC-links. A new space vector algorithm is presented suitable for this PRDCL inverter. The suggested algorithm is able to eliminate narrow PWM pulses that impede DC-link operation. This PWM control, however, requires complex and precise timing sequences in relation to PRDCL operation, which is nicely solved by adopting a new programmed controller with a buffer and a programmable timer.     

Real-Time Calculation of Switching Angles Minimizing THD for Multilevel Inverters With Step Modulation

Multilevel inverters have been widely applied in industries. A family of optimal pulsewidth modulation (PWM) methods for multilevel inverters, such as step modulation, can generate output voltage with less harmonic distortion than popular modulation strategies, such as the carrier-based sinusoidal PWM or the space vector PWM. However, some drawbacks limit the application of optimal PWM. One of such crucial drawback is that the optimal switching angles could not be calculated in real-time and one has to rely on lookup tables with precalculated angles. We propose a novel real-time algorithm for calculating switching angles that minimizes total harmonic distortion (THD) for step modulation. We give a mathematical proof that the output voltage has the minimum THD. We implemented the algorithm on a digital signal processor and provide experimental results that verify the performance of the proposed algorithm.      

Space Vector Sequence Investigation and Synchronization Methods for Active Front-End Rectifiers in High-Power Current-Source Drives

Space vector pulsewidth modulation (PWM) schemes for the active front end of a high-power drive normally produce low-order and suborder harmonics due to the low switching frequency and the drifting of synchronization between the PWM waveform and the rectifier input frequency. To provide a synchronized PWM and achieve the best harmonic performance, different space vector sequences suitable for a current-source converter are investigated in this paper. Details on how to achieve the waveform symmetries with a minimum switching frequency for each sequence are discussed. A thorough comparison of the harmonic performance of different space vector sequences is carried out. An optimum space vector modulation method by switching between two best sequences is proposed to achieve the best line-current total harmonic distortion with reduced switching losses. In addition, two synchronization methods, namely a PWM frame regulation method and a direct digital phase-locked loop synchronization method, are proposed. Both methods are equally effective in providing tight synchronization of the PWM waveform with the rectifier input frequency. The work has been verified in simulation and experiment.     

Space vector PWM technique with minimum switching losses and avariable pulse rate [for VSI]

A novel randomized control strategy for three-phase voltage source inverters, based on voltage space vectors, is described. An implicit asymmetrical modulating function results in switching losses in the inverter being reduced by about half in comparison with those using the classic space vector pulsewidth PWM method. The pulse rate is varied within individual 60° sectors of the vector plane, so that the power spectra of the output voltage are spread over a wide frequency range and acquire a continuous part. Relevant theoretical analyses, computer simulations and experimental results are presented