单周期控制三相电压型PWM整流器

文章对基于单周期控制的三相PWM高功率因数整流器进行了研究,推导了单周期控制三相电压型PWM整流器的控制规律。它不需要乘法器更不需要对输入电压进行检测,其控制逻辑简单并且以恒定频率工作,可以在每个开关周期控制输入电流跟踪正弦参考量,从而实现低电流谐波畸变和高功率因数。基于Multisim2001软件平台,建立了基于单周期控制的三相电压型PWM整流器的仿真模型,完成了6kW三相PWM整流器的设计和实验研究,仿真和试验结果都验证了理论分析的正确性。     

Performance investigation of a current-controlled voltage-regulatedPWM rectifier in rotating and stationary frames

Active front-end rectifiers with reduced input current harmonics and high input power factor will be required in the near future for utility interfaced applications. In order to meet the new and more stringent regulations with force-commutated switches, the voltage source inverter approach is superior to the conventional current source approach, in terms of number of components and control options. However, the straightforward power angle control of the rectifier is characterized by a slow response and potential stability problems. This paper proposes a current-controlled PWM rectifier as an alternative. It provides near sinusoidal input currents with unity power factor and a low output voltage ripple. Moreover, it produces a well-defined input current harmonic spectrum, exhibits fast transient response to load voltage variations, and is capable of regenerative operation. PWM pattern generation is based on a carrier technique and the current controller is implemented in the: (a) stationary (abc) frame; and (b) rotating (dqo) frame. The design and the performance of the two controller options are investigated and compared     

Implementation of a three-level rectifier for power factorcorrection

In this paper, a new single-phase switching mode rectifier (SMR) for three-level pulse width modulation (PWM) is proposed to achieve high input power factor, low current harmonics, low total harmonic distortion (THD) and simple control scheme. The mains circuit of the proposed SMR consists of six power switches, one boost inductor, and two DC capacitors. The control algorithm is based on a look-up table. There are five control signals in the input of the look-up table. These control signals are used to control the power flow of the adopted rectifier, compensate the capacitor voltages for the balance problem, draw a sinusoidal line current with nearly unity power factor, and generate a three-level PWM pattern on the AC side of adopted rectifier. The advantages of using three-level PWM scheme compared with two-level PWM scheme are using low voltage stress of power switches, decreasing input current harmonics, and reducing the conduction losses. The performances of the proposed multilevel SMR are measured and shown in this paper. The high power factor and low harmonic currents at the input of the rectifier are verified by software simulations and experimental results from a laboratory prototype     

A multilevel buck converter based rectifier with sinusoidal inputs and unity power factor for medium voltage (4160-7200 V) applications

A novel rectifier topology for high power (0.5 to 10 MVA) current source based AC motor drives is proposed. This rectifier is composed of a multi-winding transformer, a multi-level diode rectifier and a modified multi-level buck converter. The rectifier produces near unity input power factor and sinusoidal input current under any operating conditions. In addition, the proposed rectifier features reliable operation and low manufacturing cost. In this paper, the operating principle of the proposed rectifier is introduced. A number of design issues are investigated, which include PWM switching patterns, input power factor and line current harmonic distortion. Some design considerations such as the effect of the line inductance discrepancy on system performance are addressed. Experiments on a 5 kVA/208V four-level prototype are carried out for verification.     

Techniques for minimizing the input current distortion ofcurrent-controlled single-phase boost rectifiers

Techniques for minimizing the input current distortion of current-controlled single-phase boost rectifiers are described. The switching patterns of several boost rectifiers are examined to identify the nature of their input current waveforms. This analysis is used to examine the low-frequency current distortion levels, and hence the power quality, associated with the rectifiers. A PWM (pulse width modulation) strategy that selectively switches between positive unipolar PWM and negative unipolar PWM, called phase-adjusted unipolar PWM, is shown to produce the lowest current distortion levels. A novel two-switch asymmetrical half-bridge rectifier is presented that draws an input current at a unity fundamental power factor and with the same low distortion as obtained with the four-switch H-bridge rectifier. The operation of the various rectifiers is examined with reference to theoretical predictions, circuit simulations, and experimental results. This analysis is used to compare the performances of the various rectifier switching patterns     

A three-phase half-controlled rectifier with pulse width modulation

A three-phase pulse-width-modulated (PWM) half-controlled rectifier using a novel PWM control strategy whereby the low-order harmonic content in both the input current and the output voltage is reduced is presented. The circuit operates with a unity displacement factor at its input and uses minimum power components. The PWM strategy developed can be implemented on a three-phase half-controlled rectifier bridge with only three controlled switches to obtain PWM controlled rectification. Although the circuit operation is explained with force-commutated SCR switches, the basic controlled PWM operation is valid for any type of switch control. The circuit has wide applications ranging from rectifiers to battery chargers to motor drives. Even if an input current filter is desired, its size will be small due to the PWM pattern used     

Low-harmonic GTO converter for fundamental power factorcompensation

A low-harmonic GTO (gate turn-off) thyristor AC-to-DC converter with line current lead-lag phase shift control ability is proposed and analyzed. The converter can be used either as a low-harmonic GTO-controlled rectifier or a fundamental input power factor compensator in a power supply system. The effect of PWM (pulse width modulation) current phase number on the harmonic contents and converter output voltage control range is investigated. Lower order input current harmonics are eliminated over a wide range, using a specially designed PWM current pattern. The effect of the PWM current pulse number on the power factor compensation characteristic is investigated     

A New Control Method for Input–Output Harmonic Elimination of the PWM Boost-Type Rectifier Under Extreme Unbalanced Operating Conditions

Under severe fault conditions in the distribution system, not only input voltages but also input impedances must be considered as unbalanced. This paper presents a new control method for input–output harmonic elimination of the pulsewidth-modulation (PWM) boost-type rectifier under conditions of both unbalanced input voltages and unbalanced input impedances. The range of imbalance in both input voltages and input impedances, for which the proposed method is valid, is analyzed in detail. An analytical approach for complete harmonic elimination shows that PWM boost-type rectifier can operate at unity power factor under extremely unbalanced operating conditions resulting in a smooth (constant) power flow from ac to dc side. Based on the analyses in open-loop configuration, a feedforward control method is proposed. Elimination of harmonics at ac and dc side of the converter affects the cost of dc link capacitor and ac side filter. The proposed method is very useful when the PWM boost-type rectifier is subject to extreme imbalance due to severe fault conditions in the power system. In addition, by using the proposed method, the PWM boost-type rectifier can be operated from the single-phase supply in cases where three-phase source is not available. Simulation results show excellent response and stable operation of the PWM boost-type rectifier under the proposed control algorithm. Experimental and simulation results are in excellent agreement.      

一种充电设备整流电路新型控制策略的研究

在此将三相PWM整流电路应用于充电设备主电路,以达到充电设备输出长期稳定、可靠性好、输出纹波小、传递效率高的要求。在整流器控制策略上采用基于电压定向的的矢量控制,对电压定向原则进行了分析,并推导了dq轴电流解耦方式。仿真结果表明采用该方案整流器能快速跟踪给定,具有直接电流控制的动态响应快、稳态性能好的特点。由于采用了网侧电流闭环控制也使网侧电流变化对系统参数不敏感,从而增强了电流控制系统的鲁棒性。     

基于DSP实现的高频整流电源

详细介绍了如何用TMS320F240与智能功率模块IPM实现滞环电流控制的高频整流电源。实验样机表明该整流电源输入功率因数高、对电网污染小、结构简单且工作可靠，可作为大功率不间断电源的输入电路。     

三相电流型整流器空间矢量调制仿真研究

相对于传统的电压型PWM整流器而言,电流型PWM整流器用于电机驱动具有动态响应快,便于实现再生制动和四象限运行,限流能力强,短路保护可靠性高,能在宽范围内精确控制转矩和速度等优点,在小、中等功率得到广泛的应用。利用三相电压型整流器（VSR）的电压空间矢量调制技术（SVM）实现三相电流型整流器（CSR）的三逻辑空间矢量调制,对其数学模型进行了推导,并利用Matlab建立了系统的仿真模型。仿真结果证明了该方法的有效性,实现了电流型整流器交流侧的单位功率因数和直流侧电流的平稳运行,对电力无功补偿和谐波抑制具有很好的效果。     

A fuzzy-controlled active front-end rectifier with current harmonicfiltering characteristics and minimum sensing variables

A control strategy which allows conventional voltage-source current-controlled (VSCC) pulsewidth modulation (PWM) rectifiers to work simultaneously as active power filters is presented. The proposed control strategy also allows compensating the system power factor and compensating unbalanced loads. The measurement and/or calculation of the harmonics and reactive power are not required, making the proposed control scheme very simple. The active front-end rectifier acts directly on the mains line currents, forcing them to be sinusoidal and in phase with the mains voltage supply. To improve the dynamic of the system, the amplitude of the current is controlled by a fuzzy system, which adjusts the DC-link voltage of the PWM rectifier. The strategy is based on connecting all the polluting loads between the PWM rectifier and their input current sensors. The main advantages of this approach are the following: (1) there is no need to install a specially dedicated active power filter; (2) it also works simultaneously as a power factor compensator; and (3) no special and complicated calculations are required for harmonic elimination. The viability of the proposed active front-end rectifier is proved by simulation and with experimental results obtained from a 2 kVA PWM prototype     

三相电压型PWM整流器设计

本文在对比了电压型和电流型PWM整流器的基础上,采用模块化设计思想设计了一种具有工程实用性的三相电压型PWM整流器,包括主电路、驱动电路、检测电路及保护电路的设计,并利用MATLAB进行相关仿真,仿真结果表明本方案达到提高功率因素的目的。     

单相PWM整流器控制方法及谐波分析

传统二极管不控整流或晶闸管相控整流,对电网注入大量谐波及无功功率,造成电源污染.PWM整流器采用全控型开关器件取代二极管或半控型器件,并将PWM控制技术引入整流器,在稳定直流电压输出同时,使交流侧电源电流接近正弦波,实现能量的双向流动.通过介绍单相PWM整流器的控制方法,利用Matlab/Simulink搭建仿真模型,比较分析不同控制方式下PWM整流器运行时电压波形及输入电流的谐波频谱.     

电网不平衡条件下三相电压型PWM整流器非线性控制研究

本文提出了一种电网不平衡条件下三相电压型PWM整流器的控制方法。首先,建立了三相电压型PWM整流器的数学模型,基于网侧单位功率因数及负载电压恒定的控制目标,建立了网侧电流给定方程组。其次,基于“三相不平衡abc静止坐标系”与“不平衡坐标变换”建立的dq解耦模型,采用输入-输出线性化的电流控制策略,实现了有功电流与无功电流的独立控制。仿真实验结果表明：文中所提出的控制策略是有效的。     

电网不平衡条件下PWM整流控制策略的研究

通常情况下由于各种原因三相电网电压是不完全平衡的.这就使得常规的PWM整流器整流效率较低,为了提高电网不平衡条件下PWM整流器的整流效率,本文讨论了一种在电网不平衡条件下PWM整流的控制方法,在分析不平衡电网数学模型的基础上,建立了正、负序双电流控制策略的数学模型,利用Simplorer7.0对系统进行了仿真,通过对不平衡条件下常规的PWM整流器和不平衡条件下正、负序双电流控制的仿真结果进行对比,表明正、负序双电流控制可以提高网侧功率因数,改善系统的动态性能,同时得到较平稳的整流输出电压,有利于提高系统整体的运行效率。     

矩阵整流器输入与输出滤波器特性的研究

矩阵整流器是一种真正的降压型四象限AC-DC变换器,可以用在各种三相电压供电的直流电源领域。鉴于矩阵整流器采用波形高频合成原理实现输入电压-输出电压的变换和输出电流-输入电流的变换,并非纯硅变换器,输入LC滤波器与输出LC滤波器的设计至关重要,并决定着整流器系统的功能、性能和可靠性。在理论分析矩阵整流器与电流源PWM整流器具有共同变换本质的基础上,采用电路DQ转换方法,建立输入LC滤波器-矩阵整流器-输出LC滤波器系统的DC等效电路,重点分析了DC特性高低对滤波器参数设计要求,进而给出设计原则和参数选择公式,并进行实验验证。     

A complete DC and AC analysis of three-phase controlled-current PWMrectifier using circuit D-Q transformation

A recently proposed circuit P-Q transformation is used to analyze a three-phase controlled-current PWM rectifier. The DC operating point and AC transfer functions are completely determined. Most features of the power converter are clearly interpreted. They are: (1) the output voltage can be controlled from zero to maximum; (2) the system is equivalently an ideal current source in the steady state; (3) the system can be described as linear circuits; and (4) the input power factor can be arbitrarily controlled within a certain control range     

A novel load current control method for a leading power factorvoltage source PWM rectifier

A novel PWM voltage source rectifier, controlled by the load DC current instead of the DC voltage, has been developed. Its main characteristics are: (a) there is neither input current sensors nor DC voltage sensor; (b) it works with an unchangeable and predefined PWM pattern; (c) it presents a very strong stability; (d) its stability does not depend on the size of the DC capacitor; (e) it can work at leading power factor for all load conditions; and (f) it can also work with zero regulation for all load conditions. Digital simulations, analyses, and experiments confirm all these characteristics of the control method     

A predictive instantaneous-current PWM controlled rectifier withAC-side harmonic current reduction

A new single-phase bridge rectifier controlled by a predictive instantaneous-current PWM control scheme for reducing AC-side harmonic currents and improving power factor is proposed. The rectifier can operate at the unity displacement power factor and has fast response to an input signal as a current reference. The effect of the DC-side voltage ripples is taken into account. The paper describes three digital control schemes for such rectifiers and presents experimental and simulation studies on steady-state and dynamic performances of the rectifier. The effectiveness of the control schemes is confirmed by experiments and simulations. The proposed rectifier can be used for applications such as UPS systems and static VAr compensators