三相PWM整流器的前馈解耦控制与仿真研究

基于前馈解耦控制策略,研究了三相电压型PWM整流器的建模与控制问题。首先,在d-q旋转坐标系下建立了三相电压型PWM整流器的数学模型,给出了三相电压型PWM整流器的双闭环控制结构,按此方法确定了电压、电流PI调节器的设计方法。仿真结果表明该方法能使所设计的PWM整流器运行于单位功率因数,输出的直流电压稳定在期望值且具有快速的动态响应,满足了设计要求。     

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。     

直接电流控制的三相桥式PWM整流电路的设计与分析

文章对直接电流控制的PWM整流电路开展研究,主要内容如下：（1）设计BOOST型三相桥式PWM整流器的主电路。（2）设计基于直接电流控制的PWM整流电路的控制系统。（3）建立直接电流控制系统Simulink仿真模型,进行仿真分析。仿真结果证明直接电流控制方案使得PWM整流器功率因数接近于1,流入电网的电流基本接近正弦波,对电网的谐波污染小。     

A unity power factor PWM rectifier with DC ripple compensation

This paper presents a new topology for a pulsewidth modulation (PWM) rectifier which achieves unity power factor on the AC supply side and ripple reduction on the DC output side. The main circuit of this rectifier consists of a conventional PWM rectifier and a pair of additional switches. The switches and PWM rectifier are controlled such that the ripple current on the DC line is reduced, and unity power factor is achieved on the AC line. As a result, this circuit does not require a large DC capacitor or a passive LC resonant circuit. Furthermore, control of the additional switches and PWM rectifier requires only a simple control circuit. The effectiveness of this circuit was confirmed by experiments and analysis. The rectifier is useful for uninterruptible power systems (UPSs) and DC power supplies, especially for cases in which batteries are connected to the DC line     

基于虚拟电网磁链定向的三电平PWM整流器矢量控制研究

为实现无网侧电压传感器的三电平PWM整流器控制,在分析三电平PWM整流器数学模型的基础上,采用一种新颖的虚拟磁链观测器,提出了基于虚拟电网磁链定向的三电平PWM整流器矢量控制策略,在双三电平变频器系统中对其进行了实验研究。实验结果表明,该控制系统可提高整流器功率因数,并具有良好的动静态特性。     

基于PMSG的风电系统并网控制策略研究

针对直驱型风力发电不控整流＋Boost＋PWM逆变器并网拓扑结构,利用Matlab/Simulink软件平台,搭建了整个并网系统的仿真模型,并对网侧PWM逆变器进行了控制策略的研究。仿真结果表明,这种控制策略能稳定直流电压,使风电机组能正确地并入电网,实现了有功、无功的解耦及单位功率因数控制。     

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。     

三相电压型PWM整流器控制策略的研究

为了减小用电设备对电网的谐波污染和提高自身的功率因数,PWM整流器的应用越来越广泛。文中根据PWM整流器在两相同步旋转坐标系下的数学模型,运用矢量控制的思想,实现了有功和无功的解耦控制。试验结果表明,控制方法具有响应速度快,稳态性能好,整流器接近单位功率因数运行,可显著抑制谐波对电网的干扰,改善电网运行品质,节约能源。     

三相PWM整流器直接功率控制的仿真研究

基于三相电压型PWM整流器的原理与结构组成,采用电压定向的不定频直接功率控制(VO-DPC),通过对其控制结构的分析,建立其MATLAB/SIMULINK仿真模型.根据仿真结果可以看出,直接功率控制的控制算法简单,而且可以提高整流器的功率因数,有效降低谐波含量.     

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 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     

三相双向PWM整流器模型与控制电路设计

为解决传统多脉冲变压整流器架构复杂,功率因数随着电压频率增加,输入功率因素也相应减少的问题。文中采用高频功率变换技术,对PWM整流器的模型与控制电路设计方法进行了分析,并在此基础上介绍了主电路参数的设计。并通过仿真和试验结果表明,文中所述设计的PWM整流器,达到了抑制谐波电流的目的,并可满足直流侧电压的抗干扰性和动态稳态性能,为PWM整流器参数的设计提供了参考。     

A novel ZCS-PWM power-factor preregulator with reduced conduction losses

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-current-switching PWM (ZCS-PWM) auxiliary circuit is configured in the presented ZCS-PWM rectifier to perform ZCS in the active switches and zero-voltage switching in the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZCS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path and the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Nine transition states for describing the behavior of the ZCS-PWM rectifier in one switching period are described. The PWM switch model is used to predict the system performance. A prototype rated at 1 kW, operating 50 kHz, with an input ac voltage of 220 V/sub rms/ and an output voltage 400 V/sub dc/ has been implemented in laboratory. An efficiency of 97.3% and power factor over 0.99 has been measured. Analysis, design, and the control circuitry are also presented in this paper.     

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     

DC voltage control and stability analysis of PWM-voltage-typereversible rectifiers

A PWM voltage rectifier has useful characteristics on its DC and AC sides. On its DC side, a DC-link unidirectional voltage is obtained and bidirectional power transfer capability is possible by reversing the flow direction of the DC-link current. On its AC side, near sinusoidal current waveforms and AC four-quadrant operation can be obtained, leading to high-quality power being exchanged between the power converter and the mains. The use of AC filters becomes unnecessary. The rectifier DC voltage must be regulated to a constant value. In this paper, three solutions for the DC voltage control are presented. In the first solution, the DC voltage is controlled by acting upon the quadrature component of the power converter fundamental Park's voltages with relation to the mains voltages. Slow responses are necessary because of stability reasons. Also, load power variations produce both active and reactive power variations in the power converter AC side. To improve the DC voltage response, a second control solution is presented. The power converter currents in Park's coordinates must be controlled. The DC voltage is controlled by controlling the direct Park's current component and, thus, acting only on the active power of the converter AC side. Faster responses are achieved. In this case, load power variations do not produce reactive power variations in the converter AC side. The third control solution is a simplified version of this last one. Experimental results from a 2 kVA IGBT-based prototype showing good system dynamic performance are presented     

A new single-phase ZCS-PWM boost rectifier with high power factor and low conduction losses

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-current switching PWM (ZCS-PWM) auxiliary circuit is configured in the presented ZCS-PWM rectifier to perform ZCS in the active switches and zero-voltage switching (ZVS) in the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZCS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved because of the following reasons: 1) the circulating current for the soft switching flows only through the auxiliary circuit; 2) a minimum number of switching devices are involved in the circulating current path; and 3) the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Seven transition states for describing the behavior of the ZCS-PWM rectifier in one switching period are described. The PWM-switch model is used to predict the system performance. A prototype rated at 1 kW, operating at 60 kHz, with an input alternating current voltage of 220 V/sub rms/ and an output voltage of 400 V/sub dc/, has been implemented in laboratory. An efficiency of 98.3% and a power factor over 0.99 have been measured. Analysis, design, and the control circuitry are also presented in this paper.     

Technique for sensing inductor and DC output currents of PWM DC-DCconverter

The design, analysis and trade-offs of a novel method to sense the inductor and DC output currents of PWM converters are presented. By sensing and adding appropriately the currents in the transistor, rectifier and capacitors of a converter using current transformers, the waveforms of inductor and DC output currents can be reconstructed accurately while maintaining isolation. This method offers high bandwidth, clean waveform, practically zero power dissipation and simple circuit. The technique is applicable to all PWM converters in both continuous and discontinuous modes, and is most suitable for the implementation of current mode control schemes like hysteretic, PWM conductance control, and output current feedforward. This approach has been experimentally verified at a wide range of current levels, duty cycles, and switching frequencies up to 1.4 MHz     

A line-voltage-sensorless synchronous rectifier

A line-voltage-sensorless control for three-phase pulsewidth-modulated (PWM) synchronous rectifiers is presented. A line synchronization and unity power factor control are described. Indirect synchronization without sensing the line voltage allows a standard vector-controlled inverter to be used as a synchronous rectifier without requiring any additional hardware. Furthermore, the line synchronization can be properly operated under line voltage distortion or notching and line frequency variation. All control functions are implemented with a single-chip microcontroller. It is shown via experimental results that the proposed controller gives good performance for the synchronous rectifier     

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.     

A fully software-controlled PWM rectifier with current link

A fully-software-controlled pulse-width-modulated (PWM) rectifier with a current link is presented. The rectifier uses six switches to connect the three-phase source of the load directly. Line power factor is controlled while maintaining DC current. The input filter of the rectifier is analyzed, showing that unity power factor is achieved by the lagging of the input current of the rectifier with respect to the source voltage. The PWM technique is developed using a space vector modulation, and its implementation is carried out with a minimal control hardware structure based on a 16 b single-chip microcomputer. It is shown experimentally that the scheme gives good performance