单位功率因数三相PWM变流器的相量调节方法

本文提出一种基于幅相控制方式单位功率因数三相电压型PWM变流器的相量调节方法。根据相量间的直角三角形关系和能量转换平衡原则，建立了该系统的低频数学模型，分析了系统的相量调节方式。在此基础上，提出一种电流前馈的调节方式，即将直流侧负载电压的变化率转化为到达下一个平衡状态时相位与调制深度的附加控制量，以提高系统的快速性。实验证明：控制系统实现了单位功率因数和能量的双向流动，且输出直流电压恒定可调，相电流的谐波含量非常小，系统动态性能较好。     

一种三相PWM变流器的功率因数调节方式

提出了一种基于幅相控制、实现功率因数可调的三相PWM变流器控制方法.通过建立系统低频数学模型,分别在整流和逆变状态下,探讨系统实现功率因数、从电网吸收或回馈容性、感性无功功率的动态调节过程.分析了控制角、受控的功率因数角、最大负载能力、最大回馈电网电能与调制深度、负载、电感量之间的关系.实验表明,该PWM变流器具有控制...     

滞环电流控制的新型三相电压型变流器

随着电力电子技术的发展,可逆变流装置得到了广泛应用传统的相控整流器存在功率因数低、输入电流谐波成分高等缺点,影响了电网的供电质量。针时这类非线性负载所产生的负面影响,提出了一种滞环电流控制的新型三相电压型变流器,分析了系统的控制原理,论述了系统的设计过程,运用Psim软件进行仿真分析,采用IGBT作为功率元件,基于DSP构造了一套可逆变流器装置。该装置实现了单位功率因数,并使输入电流为正弦电流,得到了与仿真分析相一致的试验结果     

滞环电流控制的新型三相电压型变流器

随着电力电子技术的发展,可逆变流装置得到了广泛应用.传统的相控整流器存在功率因数低、输入电流谐波成分高等缺点,影响了电网的供电质量.针对这类非线性负载所产生的负面影响,提出了一种滞环电流控制的新型三相电压型变流器,分析了系统的控制原理,论述了系统的设计过程,运用Psim软件进行仿真分析,采用IGBT作为功率元件,基于DSP构造了一套可逆变流器装置.该装置实现了单位功率因数,并使输入电流为正弦电流,得到了与仿真分析相一致的试验结果.     

一种新型高功率因数变流器研究

研究了一种新型高功率因为流器,采用ＴＬ４９４对开关器件进行ＰＷＭ控制,可输入电流波形近似正弦波,功率因妆近为１。在介绍电路工作原理基础上,重点对其输入电流进行了分析,给出了计算机仿真与实验结果。     

一种功率因数改进型可控硅变流器及应用

常规的三相桥式可控硅整流电路在调速领域内已获得了广泛的应用，但是这种变流器的应用自身存在着功率因数低电流谐波大等缺点，至今无法解决，本文提出了一咱具有４线桥结构的改进型变流器。这种改进型变流器的突出特点是提高功率因数，降低电流谐波和提高输出分辨率。具有良好的节能效果。文中主要讨论分析了改进型变流器本身的运行原理及在直流调速训的应用。     

三相单位功率因数整流器的电流控制方法研究

在三相单位功率因数整流器中，实际电流能否跟踪参考电流将影响整个系统的控制性能，文章指出了一种适合数字化控制的电流控制方法，以李雅普诺夫直接法为基础，引入了反馈增益，用来抑制系统参数变化的影响，并比较了变反馈增益和定反馈增益的效果。仿真结果表明了该方法将有效地克服系统参数变化对控制性能的不利影响。     

一种功率因数校正变流器的研究

研究了一种由带中心抽头变压器与斩波器构成的交流器，理论分析表明可以调制输入电流波形，达到消除低次谐波、提高功率因数的目的，给出了计算机仿真结果。     

一种三相电压型SPWM变流器的实现

本文基于三相电压型SPWM变流器的稳态控制模型，采用相位和调制深度的协调控制完成功率因数调节和输出直流电压稳定，并导出该控制模式下功率因数可控的必要条件。实验验证了该变流器方案的可行性。     

间接电流控制可调功率因数电流型PWM变流器

电流型PWM变流器（PWM-CSC）因其良好的功率因数和直流电流源特性，可望在某些场合取代产生大量谐波的二极管或晶闸管相控整流装置，但是，PWM-CSC本身的强耦合非线性特性，使得变流器常采用复杂的直接电流控制策略，实现功率因数可调和能量回馈非常困难。提出一种基于dq坐标系的间接电流控制方法，该方法将变流器的直流输出作为网侧电流有功分量的给定值，通过此给定值和tgj的乘积调节无功电流的大小，然后利用PWM-CSC交流侧电流的离散方程，求出当前变流器的控制量，间接控制变流器的网侧电流，从而控制了变流器的有功功率和无功功率，实现了变流器的可调功率因数和能量回馈。论文最后对变流器的稳定运行范围进行了讨论，得出变流器提供的无功功率受有功功率限制的结论。     

基于自然坐标与功率前馈的三相电压型PWM变流器控制

针对三相电压型PWM变流器控制系统,提出一种自然坐标与负载功率前馈控制方法。根据p-q理论在自然坐标下的表征,引入瞬时有功电压和瞬时无功电压的概念。从而基于电网电压定向的矢量控制策略引入PWM变流器的自然坐标控制方法,省去了电网相位检测和坐标系变换,降低控制复杂度。针对PWM变流器矢量控制下直流侧负载(包括有源负载和无源负载)功率波动对直流侧电压产生较大冲击和波动问题,基于功率平衡和p-q理论推导了负载扰动点到三相交流电流指令的前馈通道增益矩阵,提高PWM变流器直流侧稳压控制的鲁棒性。RCP实验证明所提方法的正确性和可行性。     

Dual voltage converter with improved power factor and enabling voltage control

In this paper, a novel version of the dual voltage converter is presented with improved voltage regulation and enabling a wide range of voltage control by using self-turn-off devices (power transistors) instead of diodes. Further, this system operates with unity displacement factor. We have obtained the analytical expressions of this circuit. The results are, however, quite complex. We could calculate values of the voltage and current waveforms by using a computer. The calculated values are essentially in agreement with the experimental values. Experimentally, an ideal load characteristic with null voltage regulation was obtained by the conduction angle control for power transistors. Further, a wide range of voltage from 220 V to 39 V was obtained. A disadvantage for this system is the requirement for snubber circuits with a larger value of capacitor in order to suppress the surge voltages at turn-off periods.     

Diode-clamped multi-level power converter with a zero-sequence current loop for three-phase three-wire hybrid power filter

This paper proposes a three-phase three-wire hybrid power filter configured by a three-phase passive power filter and a three-phase diode-clamped multi-level power converter with a small power capacity of zero-sequence current loop connected in series to compensate for the harmonic currents of nonlinear load. The salient feature is that a small power capacity of zero-sequence current loop is applied to overcome the problem of balancing voltages of two DC capacitors for a diode-clamped multi-level power converter applying in the three-phase three-wire hybrid power filter. A laboratory prototype is developed to verify the performance of the proposed three-phase three-wire hybrid power filter. The experimental results have demonstrated the feasibility and practicality of the proposed three-phase three-wire hybrid power filter.     

高功率因数三相软开关PWM变流器

本文提出一种三相软开关PWM变流器,它具有电路结构简单,开关次数较传统变流器少的特点,电路的开关切换是以单纯的ZVS方式进行的,从而可以减少开关损耗和抑制EMI。文章阐述了变流器输入功率因数为1和输出直流电压恒定的控制方法,通过改变调制信号的调制度a和相位角φ,不但可以使输入电流和相电压保持同相位,输入电流波形为正弦波,而且可以使输出直流电压保持恒定。     

一种双PWM变换器新改进型直接功率控制策略*

为了解决双PWM变换器常规直接功率控制的电压外环响应速度慢的问题,提高控制系统跟踪性能,首先,设计了一种新型开关矢量表,在某些扇区由原来的一个矢量控制变为两个矢量控制,从而改善有功功率和无功功率的变化程度在不同扇区影响的差异性,增强灵敏程度和实时性;其次,提出电机侧功率向前反馈的控制策略,增设反馈网络,提高响应速度,确保功率给定,改变了常规电压外环缓慢的调整过程。并在功率波形、突加负载的响应速度、电网电流、谐波等方面,与常规直接功率控制进行了实验对比。实验结果表明,本文设计的控制系统能在负载变化时实现快速跟踪响应并恢复和保持稳态,验证了该策略的有效性。     

A voltage-source PWM rectifier-inverter with feedforward control of instantaneous power

In general, diode rectifiers with electrolytic capacitors on the dc side have been used as dc power supplies for voltage-source inverters. Rectifiers of this type, however, cause many problems such as poor power factor and harmonics. Recently, voltage-source PWM rectifier-inverters have been studied to provide the following advantages: (1) harmonic-free on both ac sides; (2) unity power factor on the input ac side; (3) power flow of either direction or power regeneration; (4) reduction of the dc capacitor. However, it is difficult for a conventional voltage-source PWM rectifier-inverter to regulate the capacitor voltage on transient states because it has only a voltage feedback loop. This paper describes a voltage-source PWM rectifier-inverter with feedforward control of instantaneous power. Based on the pq theory, the instantaneous power which is calculated in the control circuit of the inverter is fed forward to the control circuit of the rectifier. The feedforward control of instantaneous power contributes greatly to sufficiently suppress voltage fluctuation of the dc capacitor on transient states. Transient characteristics are discussed, and some interesting experimental results of a laboratory model are shown.     

Synchronous control of indirect matrix converter for three-phase power conditioner

This paper describes an average model of indirect matrix converter (IMC) with an output LC filter in stationary and rotating reference frames. The developed model is non-linear and should be linearized in order to design linear controllers. Transient performance of the IMC is compared with that of conventional inverter in classic AC/DC/AC system. In order to make the IMC applicable for power conditioner applications a synchronous controller is designed. A power conditioner acts in one or more ways to deliver a voltage of the proper level and characteristics to enable load equipment to function properly. In order to afford the power conditioner requirements the controller has two segments. One segment controls the IMC with balanced input supply voltage and the other controls the system with unbalanced input supply voltage. The system can provide balanced output voltages with slight distortion of line side currents. Theory analyses, the model validation and simulation results are presented to verify the effectiveness of this control method.     

A voltage source PWM rectifier-inverter with feedforward control of instantaneous power

In general, diode rectifiers with electrolytic capacitors on the dc side have been used as dc power supplies for voltage source inverters. This type of rectifiers, however, causes many problems such as poor power factor and harmonics. Recently, voltage source PWM rectifier-inverters have been studied to provide the following advantages; (1) harmonic-free on both ac sides; (2) unity power factor on the input ac side; (3) power flow of either direction or power regeneration; (4) reduction of the dc capacitor. It is, however, difficult for a conventional one to regulate the capacitor voltage on transient states because of having only a voltage feed-back loop. This paper describes a voltage source PWM rectifier-inverter with feed-forward control of instantaneous power. Based on the pq theory, the instantaneous power which is calculated in the control circuit of the inverter is fed forward to the control circuit of the rectifier. The feed-forward control of instantaneous power makes a great contribution to sufficiently suppress voltage fluctuation of the dc capacitor on transient states. Transient characteristics are discussed and some interesting experimental results of a laboratory model are shown.