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     

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。     

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     

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 Novel Three-Phase PFC Rectifier Using a Harmonic Current Injection Method

This paper proposes a novel circuit topology for a three-phase power factor correction (PFC) rectifier using a harmonics current injection method. In consideration of lower cost, the harmonics injection method is more suitable than a conventional six-arm pulse width modulation (PWM) rectifier. The harmonics injection current is simply generated by only one switching leg. As a result, the proposed circuit has the advantage of only two switches. An optimal injection current is achieved in order to obtain an input current of sinusoidal waveforms. This paper discusses the basic operation and optimal design method for the proposed circuit. In addition, the validity of the proposed circuit is confirmed by simulation and experimental results. An input current of almost sinusoidal waveform was obtained and an input current total harmonic distortion (THD) of 8.5% was obtained at a load of approximately 1 kW.     

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     

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。     

AC voltage and current sensorless control of three-phase PWM rectifiers

In this paper, a novel control scheme of three-phase PWM rectifiers eliminating both the AC input voltage and current sensors is proposed. The phase angle and the magnitude of the source voltage are estimated by controlling the deviation between the rectifier current and its model current to be zero. The input currents can be reconstructed from switching states of the PWM rectifier and the measured DC link currents. To eliminate the calculation time delay effect of the microprocessor, the currents ahead one sampling period are estimated by a state observer and then are used for feedback control. The proposed control scheme reduces the system cost and improves its reliability. The feasibility of the proposed AC sensorless technique for three-phase PWM rectifiers has been verified through experiments using a high performance DSP chip.     

三相整流桥PFC电路拓扑的分析及控制

通过对三相二假管整流挢构成的功率因数校正（PFC）拓扑电路较详尽的分析,表明在无逆变功能的要求下,只需单只全控型开关元件,经脉宽州制PWM控制。在断续导通控制模式下,便可达到功率阁数接近1和交流正弦的进线电流的目的。文巾利用了单周控制和Matlab／Simulink软件,对三相二极管整流的Boost PFC电路进行了建模和仿真,得出了预期的结果．证明在原理上是可行的。此PFC电路只用一只全控型开关元件,从而可能降低设备的成本。     

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 control method for three-phase PWM rectifiers using asingle current sensor

This paper proposes a control method for three-phase voltage-source PWM rectifiers using only a single current sensor in the DC-link. A PWM modulation strategy for reconstructing three phase currents from the DC-link current is given. When 3φ input currents cannot be reconstructed, a method for modifying the switching state of the PWM rectifier and a method for the predictive state observer is proposed. Compensation of the 2 sampling delays is also included, and this method is combined with all of the experiments. Performance differences between the two methods in a typical voltage source PWM rectifier are investigated experimentally     

A three-phase soft-transition inverter with a novel controlstrategy for zero-current and near zero-voltage switching

This paper proposes a new soft-transition control strategy for a three-phase zero-current-transition (ZCT) inverter circuit. Each phase leg of the inverter circuit consists of an LC resonant tank, two main switches, and two auxiliary switches. The proposed strategy is realized by planning the switching patterns and timings of these four switches based on the load current information. It enables all the main switches and auxiliary switches to be turned on and turned off under zero-current conditions, and achieves a near zero-voltage turn-on for the main switches. Compared with existing ZCT strategies, the diode reverse recovery current and switching turn-on loss are substantially reduced, the current and thermal stresses in the auxiliary devices are evenly distributed over every switching cycle, and the resonant capacitor voltage stress is reduced from twice the DC bus voltage to 1.3-1.4 times the DC bus voltage. The proposed strategy is also suitable for three-phase power-factor-correction (PFC) rectifier applications. The operation principles, including a detailed analyst based on the state-plane technique, and a design rule are described in this paper. The circuit operation is first verified by a computer simulation, and is then tested with a 50-kW three-phase inverter to the full power level together with a three-phase induction motor in a closed-loop speed/torque control. Significant reductions in switching losses and voltage/current stresses over existing techniques have been experimentally demonstrated     

Zero-current-switched three-phase SVM-controlled buck rectifier

A zero-current-transition (ZCT) cell is analyzed and designed to be used with a three-phase pulsewidth-modulation buck rectifier. This rectifier was space-vector controlled and used unidirectional current switches. The proposed ZCT circuit is load independent and achieves a high noise and voltage stress reduction and provides ZCTs to almost all transitions of the rectifier's switches and to the additional auxiliary switches. Theoretical equations have been obtained for design purposes. The circuit is easy to design and the driving signals for the auxiliary switches are also easy to obtain, as demonstrated in this paper.     

基于新颖磁链观测的三电平PWM整流器的模糊PI控制策略研究

三电平PWM整流器在高压大功率场合有着广泛的应用,但是由于三电平PWM整流器自身的开关器件的非线性和对电路参数的依赖性,使得传统的PI双闭环控制无法更好的提高其动态性能,因此限制了其在更宽负载范围内的运用。本文在建立二极管钳位式PWM整流器数学模型的基础上,针对目前三相PWM整流器动态性能较差的特点,采用一种新型简化虚拟磁链定向,设计了一种模糊PI控制器。仿真实验表明:该控制方法设计简单,提高了PWM整流器的动态性能,而且较好地实现了电流的解耦控制,且使系统鲁棒性增强。     

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.     

基于空间电压矢量的三相电压型PWM整流器的研究

建立了三相电压型PWM整流器在三相静止坐标系和两相同步旋转坐标系下的数学模型,将双闭环工程设计方法应用于PWM整流器,研究了其前馈解耦控制策略。在此基础上结合空间矢量调制（SVPWM）的算法,设计了三相电压型PWM整流器控制系统,并在Matlab的Simulink中进行了系统仿真。仿真结果表明,设计方法可行,具有良好的动静态性能,实现了单位功率因数。     

Three-phase sinusoidal current rectifier with zero-currentswitching

This paper presents the application of zero-current switching in a three-phase rectification scheme with nearly sinusoidal line currents. The principle of third harmonic current circulation is used to reduce the distortion in the line currents. Zero-current switching is accomplished with the use of only two switches. The operation of the circuit is verified experimentally. Comparisons with a PWM based rectifier and a six-switch rectifier in terms of component stresses and EMI filter considerations are presented     

Minimum-loss strategy for three-phase PWM rectifier

In this paper, the conduction and switching losses of a voltage-fed three-phase pulsewidth modulation (PWM) rectifier are analyzed for various PWM schemes. On the basis of this result, a novel PWM strategy which minimizes the loss of a three-phase PWM rectifier is developed. This minimization result is derived from the following two factors: (1) less switching frequency ratio; and (2) the absence of switching in the vicinity of peak input current. As a result, it is anticipated that the switching loss of the rectifier is reduced by 46%, compared with continuous space-vector PWM rectifiers, and 20% compared with conventional discontinuous space-vector PWM rectifiers. Moreover, the proposed PWM scheme can produce the highest available output voltage because it is based on the concept of the voltage space vector. The effectiveness of the proposed PWM strategy is verified by experiments