谐波含量

全负载范围内或电网电压谐波含量大时，可实现高的输出功率因数和低的进网电流ηTHD。

THD of the grid current is small and power factor is high at full range of loads or even in abnormal grid voltage .

系统样机测试结果表明：满载时，系统效率99%以上，功率因数99%以上，谐波含量5%以下，满足设计要求，验证了系统设计的可行性。

The result of experiment shows that efficiency is higher than 99 % , power factor is higher than 99 % and THD is low than 5 % in the full load . It satisfies the design requirements and it validates the feasibility of the topology .

有源功率因数校正（ActivePowerFactorCorrection，APFC）技术的优点是总谐波含量小，功率因数高。

Active power factor correction ( APFC ) technology can achieve high power factor and low total harmonic distortion ( THD ) .

然后，利用快速傅里叶变换工具（FFT）对仿真结果进行谐波含量分析。

Then , the harmonics in simulation output are analyzed by Fast Fourier Transform Algorithm ( FFT ) .

功率因数校正器采用频率固定的PI控制，实现了在各种非线性负载下降低电流谐波含量，提高功率因数的目的。

As a result , it reduces the content of harmonic current and improves the power factor with a group of nonlinear loads .

但在输入周期内占空比恒定时，输入电流谐波含量较大、输入功率因数（PowerFactor，PF）相对较低，尤其在输入电压较高时。

However , the input power factor ( PF ) is relatively low and the input current contains rich harmonics when the duty cycle is constant over the whole line cycle .

串联H桥多电平变频器具有输出电压高、功率大，输入侧和输出侧谐波含量小，输入功率因数高等特点。

The series H-bridge multilevel converter has the advantages of high output voltage , high power , lower harmonic content in line and motor sides and high input power factor .

不同的LC滤波参数对输出电压的谐波含量影响很大，滤波参数选取不当会使滤波效果不能满足设计要求。

Different LC filter parameter matching exerts a distinct influence to the harmonic voltage . Improper parameter selection may make filter unsatisfy the analysis request .

逆变器控制采用优化的特定消谐PWM技术，以滤波后总谐波含量（THD）为目标函数，计算预定开关角度。

The inverter uses optimal selective harmonic elimination PWM technology and computes predetermined switching angle , using total harmonic distortion factor as aim function .

这种新型绕组利用其中两种不同极对数p和q对应感应电势在理论上可以有不同电回路的特点，对转子导体进行重复利用，从而具有较高的利用率和低的谐波含量。

The new machine has a p / qpole wound-rotor changing-pole winding which is repeatedly used in p or q pole-pair numbers , therefore it has higher rotor conductor availability ratio and low harmonic content .

尽管与二极管整流相比，PWM整流器电网电流中的谐波含量大大降低，然而并不能完全消除，并受到各种因素的影响。

Although the grid current harmonics are much lower using PWM rectifier than that using diode rectifier , they can not be eliminated completely and are affected by many factors .

脉宽调制（PWM）技术的引入使整流器输入电流正弦化，可运行于单位功率因数，且谐波含量低。

Pulse Width Modulation ( PWM ) method makes the rectifier have the advantages of sinusoidal input current , unity power factor and low total harmonic distortion ( THD ) .

SPWM信号作为逆变桥的控制信号可产生谐波含量少，波形质量高的正弦波形。

The SPWM signals which are used as control signals of inverter bridges can produce high quality sine waveform with less harmonic content .

基于电压源逆变器（VSI）的静止无功发生器（SVG）直接应用PWM控制技术，具有结构紧凑、易于控制、谐波含量小以及功率密度大等优点。

VSI-based SVG using PWM technology has some advantages such as compact structure , simple control , little harmonics and high power density .

并对在谐波含量较多的变电站中如何应用傅氏算法精确测量基频U、I进行了探讨。

Combine to in a transformer substation with more content of power system harmonics how applied the FFT precision to measure the basic frequency U , I to carry on the study .

仿真和实验结果证明，采用PWM调制策略控制风力发电逆变器不仅可以实现灵活、可靠的控制，而且还可以减小谐波含量，从而提高逆变器输出电能质量。

The simulative and experimental results proved that PWM strategy not only provides flexible and reliable control , but also reduces the harmonic content and thus improves the inverter output power quality .

正弦脉宽调制（SPWM）逆变器作为逆变器的一种，可输出谐波含量小的正弦波形。

As one of inverters , Sinusoidal Pulse Width Modulation ( SPWM ) inverters can achieve low total harmonic distortion ( THD ) output wave .

采用SVPWM调制方式，有利用率高、开关损耗小、谐波含量低等优点。

SVPWM modulation mode with which the DC voltage utilization ratio is high , the switch wastage is small and the harmonic content is low .

论文研究的主要内容是PWM整流器的控制算法，通过对控制算法的改进，提高PWM整流器能量变换的效率，达到减小谐波含量、提高功率因数的目的。

This paper mainly investigated the algorithms of Pulse Width Modulation ( PWM ) rectifier and aimed at enhancing the efficiency of rectifier energy transform and reducing the harmonic by improving the algorithms .

在软件设计中，采用瞬时电压反馈，并采用PI控制算法，从而产生高质量的电压输出波形，减小输出电压中的谐波含量。

In software design , this article uses the transient voltage feedback and the PI control algorithm , thus result high quality output voltage waveform , reduces the harmonics content of output voltage .

该方法将参考阶梯波分为30°等间隔，通过对每个间隔幅度的单独控制来降低输出PWM波形中的谐波含量。

In this strategy , step reference waveform is divided into 30 ° intervals , and by proper setting amplitudes of the intervals , the harmonics of the inverter output voltages can be effectively decreased .

下位机程序主要实现对电网信号的采样以及各个电能参数的计算，其中包括利用FFT变换获取30次以内的谐波含量。

In the client computer program , the signal sampling and the calculation of various energy parameters are realized . The harmonic component of 0 to 30 times is acquired by using the FFT .

摘要：单相PWM整流器以高功率因数、低谐波含量以及能量可以双向流动等优点，广泛应用于新能源发电以及交流传动等领域。

ABSTRACT : Single-phase PWM rectifier has been widely used in the fields of ac electric drives and renewable energy distribution generations with the advantages of high power factor , low current harmonics and bidirectional energy flowing .

最后通过仿真得到客车逆变电源不同的LC滤波参数与逆变器输出电压谐波含量的关系。

In the end of the thesis , by carrying on system simulation , compare experiment result with simulation result . We can get the relationship between LC filter parameter and output voltage harmonics .

SVPWM能有效的减少输出电流失真及切换损耗，它与目前广泛使用的正弦式PWM比较，可以显著的增加有效输出电压及降低谐波含量。

The SVPWM can effectively lessen the distortion of output current and switch loss . Compared with sine PWM used widely at present , it can prominently increase effective output voltage and reduce harmonics .

有源PFC技术具有功率因数高和总谐波含量小等优点，在过去的二十年里，得到了长足的发展和广泛应用。

Active PFC techniques have been researched systematically and used widely in the recent twenty years because of high power factor ( PF ) and low total harmonic distortion ( THD ) .

在PWM电机驱动系统中，多电平逆变技术可以降低系统中的共模电压和谐波含量，但是由于开关频率是固定的，在开关频率处的谐波仍很大。

Applications of multilevel inverter can reduction of the common mode voltage and harmonic components in PWM motor drive systems . However , the harmonic component on switching frequency is still very high because of the fixed switching frequency .

通过PSpice仿真软件仿真和实际实验研究表明，该电路能有效提高电子镇流器的功率因数，降低输入电流的谐波含量。

Through simulation with PSpice simulator and actual experiment , it is proved that the circuit can effectively improve the power factor of electronic ballast and decrease input current harmonic distortion .

借助瞬时无功功率理论，分析了PWM整流技术能够提高串级调速系统功率因数的原理，该技术提升了系统的功率因数和减少了网侧谐波含量。

With the help of instantaneous reactive power theory , the principle that PWM rectification technology can enhance cascade speed control system power factor has been analyzed . The technology has enhanced system power factor and reduced line side harmonic content .

总之，逆变器交流输出电压和频率稳定精度均较高，电压波形的总谐波含量THD较低且正弦特性较好。

In short , the inverter AC output voltage and frequency stability precision are higher , and total harmonic content THD of voltage waveform is lower and sinusoidal characteristics are better .