Direct three-phase single-stage flyback-type power factor corrector

Based on the work of Hui and Chung (see ibid., vol. 33, no. 15, p.1274-76, 1997) a three-phase converter system consisting of three single-phase flyback-type AC/DC converter modules in star-connection is proposed and investigated     

基于二象限APF的单相功率因数校正器

为消除单相整流装置产生的谐波,提出了一种基于二象限有源滤波器(APF)的单相功率因数校正器,包括其主回路拓扑与控制策略。使用T型拓扑可滤除高次谐波,在主回路加装二极管可削减有源滤波器电流峰值,并在控制回路中使用双前馈以实现快速响应。对该拓扑和控制方案进行了Matlab仿真,并设计了基于dsPIC33F系列数字控制器的实验样机。仿真和实验结果均表明该技术可在降低成本的情况下,仍将功率因数提升至99%。     

A microprocessor-based adaptive power factor corrector fornonlinear loads

A microprocessor-based adaptive power factor corrector for poor power factor (linear or nonlinear) loads is introduced. The system power factor is measured by the microprocessor and compared with a predetermined reference value. Accordingly, the microprocessor adjusts the power factor to get the predetermined value. This is achieved by controlling the firing angle of a thyristorized static VAR (volt-ampere reactive) compensator through microcomputer software. The system power factor is measured by the microprocessor at every supply cycle, and the above sequence is repeated. The proposed scheme achieves both accurate measurement and adjustment of the system power factor     

NCP1631控制交错并联功率因数校正器的研制

采用PFC控制芯片NCP1631设计了一款工作在全电压输入范围下的交错并联PFC电路。详细分析并讨论了NCP1631芯片的特点以及PFC变换器的设计参数等,最终研制了一台500 W交错并联BOOST型PFC变换器样机。实验结果表明,采用NCP1631的交错并联PFC电路,在宽输入电压范围内具有良好的功率因数校正效果。     

Limits in boost power factor corrector operating in border-line mode

The single-phase boost power factor correctors may operate in the so called border-line mode, which is distinguished by variable switching frequency. If some constraints are imposed on variability of this frequency some limits to output voltage and power of the circuit appear at once. The paper shows the origin of them and presents formulas and graphs helpful in a proper choice of circuit parameters in order to keep the switching frequency within a predefined range, also under the changes of input line voltage and of the load resistance.     

基于DSP的单ADC数字功率因数校正器研究

传统数字功率因数校正器要使用三路ADC采样,特别是电感电流的采样会造成电路效率的下降以及复杂度的上升。研制一台基于Boost电路的数字功率因数校正器,控制回路只使用了一路ADC采样平均输出电压以及输出电压纹波。开关管所需要的占空比值会预先计算好,采样的平均输出电压形成输出平均电压环,采样的输出电压纹波形成输出电压纹波环。两个环路分别对占空比相应的部分进行控制,保证了整个系统可以达到较好的功率因数校正效果。最后,采用TMS320F28335数字信号处理器作为控制芯片,实验结果验证了该方法的正确性。     

开关电源的有源功率因数校正电路设计

有源功率因数校正可减少用电设备对电网的谐波污染,提高电器设备输入端的功率因数。详细分析了有源功率因数校正APFC(active power factor corrector)原理,采用平均电流控制模式控制原理,设计了基于UC3854BN芯片的一种有源功率因数校正电路方案,着重分析了电路主要参数的选择和设计。实践证明,采用APFC后,大大减小了输入电流的谐波分量,实现了功率因数校正。     

一种有源功率因数校正器的设计与实现

介绍了一种有源功率因数校正器的设计方法.采用Infineon公司高性能功率复合控制器TDAl6888作为控制器件,以实现功率因数校正.通过功率因数校正,大大减少了电流谐波,提高了输入端的功率因数.     

An active power factor correction technique for three-phase dioderectifiers

A novel active power factor correction method for power supplies with three-phase front-end diode rectifiers is proposed and analyzed. The implementation of this method requires the use of an additional single switch boost chopper. The combined front-end converter draws sinusoidal AC currents from the AC source with nearly unity input power factor while operating at a fixed switching frequency. It is shown that when the active input power factor correction stage is also used to regulate the converter DC bus voltage, the converter performance can improve substantially in comparison with the conventional three-phase AC-to-DC converters. These improvements include component count reduction, simplified input synchronization logic requirements, and smaller filter refractive components. Theoretical results are verified experimentally. The proposed method has the disadvantage of substantially increasing the current stresses of the switching devices and the high-frequency ripple content of the prefiltered AC input currents     

A topology survey of single-stage power factor corrector with aboost type input-current-shaper

A topological review of the single stage power factor corrected (PFC) rectifiers is presented in this paper. Most reported single-stage PFC rectifiers cascade a boost-type converter with a forward or a flyback DC-DC converter so that input current shaping, isolation, and fast output voltage regulation are performed in one single stage. The cost and performance of single-stage PFC converters depend greatly on how its input current shaper (ICS) and the DC-DC converter are integrated together. For the cascade connected single-stage PFC rectifiers, the energy storage capacitor is found in either series or parallel path of energy flow. The second group appears to represent the main stream. Therefore, the focus of this paper is on the second group. It is found that many of these topologies can be implemented by combining a two-terminal or three-terminal boost ICS cell with DC-DC converter along with an energy storage capacitor in between. A general rule is observed that translates a three-terminal ICS cell to a two-terminal ICS cell using an additional winding from the transformer and vice verse. According to the translation rule, many of the reported single-stage PFC topologies can be viewed as electrically equivalent to one another. Several new PFC converters were derived from some existing topologies using the translation rule     

Control system for three-phase active power filter whichsimultaneously compensates power factor and unbalanced loads

The effectiveness of an active power filter depends basically on three characteristics: (a) the modulation method used; (b) the design characteristics of the PWM modulator; and (c) the method implemented to generate the reference template. For the last characteristic there are many methods, most of them complicated and hence difficult to implement and adjust. In this paper, a new method, which has simplicity at its main characteristic, is presented. The method is based on “sample and hold” circuits, synchronized with the peak value of the phase-to-neutral mains voltage. This method is useful for shunt active power filters and is capable to eliminate harmonics, compensate power factor, and correct unbalance problems simultaneously. It also has the ability to slow-down sudden transient changes in the load. Experimental results, with the reference template obtained with the method, are presented in the paper     

Indirect current control of a unity power factor sinusoidal currentboost type three-phase rectifier

The indirect current control scheme has evolved from the success of the hysteresis current controlled voltage regulated rectifier, which has been shown to be capable of: unity and even leading power factor operation; near sinusoidal current waveforms; and bilateral power transfer without the need of bi-directional solid state power switches. The advance consists of replacing the inner hysteresis current feedback loop by the standard sinusoidal PWM control and in the process saving the cost of the current measuring transducers. The scheme is evaluated through tests on 1 KW size laboratory models and through digital simulations. A theory of the system dynamics is developed and stability boundaries are presented     

峰值电流控制提高三相整流功率因数的方法

在对大电容滤波的三相不控整流电路仿真研究的基础上,指出了该电路存在的工程应用局限性。在分析电流谐波畸变与功率因数之间的理论关系的基础上,提出了一种峰值电流控制提高三相不控桥式整流电路功率因数的方法,并进行了试验验证,证明其在提高功率因数的同时,有效地降低了滤波电感的体积及重量,实现三相整流滤波电路的小型化设计,具有一定的工程应用价值。     

Single-phase to three-phase power conversion interface

This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface.     

具有高功率密度的三相AC-DC 48V电源

在电力系统的电源质量国际标准规定中,电网连接设备的线电流谐波要低于门限值;因此,要求AC-DC变流器运行时要具有高功率因数和低线电流失真。本文实现了一种用于电源系统的三相AC-DC48V电力电子变流器,并进行了相关的实验测试与讨论。在电源设计上的主要限制条件是要求功率密度达到每立方分米9000W,同时供电线路中不用中性线。     

A novel three-phase single-stage distributed power inverter

In this paper, a novel three-phase, DC/AC converter suitable for distributed power applications is proposed. The system consists of three DC/DC boost converters with a common point and operating as a three-phase inverter with intrinsic step-up capability. The converter obtained can invert, amplify and, where possible, regenerate bidirectional power sources such as fuel-cells, small gas turbines, and photovoltaic arrays. There are two main advantages to the system: the use of only six insulated gate bipolar transistors and small passive elements, and the fact that it does not need reverse voltage blocking capability. Simulation and experimental results show the effectiveness of the proposed system during both steady-state and dynamic operations.     

Apparent power transducer for three-phase three-wire system

In a newly developed transducer apparent power is measured by using a multiplier, in which the AC component of the output is used. For a three-phase three-wire system, two multipliers are used according to the so-called `two wattmeter' method. The AC output components are +30° and -30° phase-shifted, respectively, and then the difference is converted to a DC signal which corresponds to the total apparent power     

A soft switching active snubber optimized for IGBT's in singleswitch unity power factor three-phase diode rectifiers

This paper describes a soft switching active snubber for an IGBT operating in a single switch unity power factor three-phase diode rectifier. The soft switching snubber circuit provides zero-voltage turn-off for the main switch. The high turn-off losses of the IGBT due to current tailing are reduced by zero-voltage switching. This allows the circuit to be operated at very high switching frequencies with regulated DC output voltage, high quality input current and unity input power factor. Simulation and experimental results are included     

用于三相工业应用系统宽电压电源

由三相交流电源供电的工业设备往往需要一个辅助电源为控制电路提供稳定的低压直流电压。但是,对这种稳压电源的技术要求比单相电源高得多,其额定输入电压比较高。而且在工业环境中,由于大负载接入电网或者脱离电网,或者由于在某个地方电网出现故障,电网电压常常会出现很大浪涌、长时间跌落或者瞬间下降。这就要求电源能够处理所有这些情况而不会出现故障。     

Reactive power reduction in three-phase electric arc furnace

A conventional three-phase electric arc furnace causes flicker at the point of common coupling with AC mains. This generally occurs with AC mains having a low short-circuit capacity. The flicker is caused by flucluating reactive power consumption of the furnace. This paper describes a way, through computer simulation, of increasing the dynamic performance of the furnace and keeping reactive power consumption constant. This can be achieved with the addition of a three-phase power controller and a booster transformer to the power source and the introduction of a new control method of regulating the reactive power input. The problem of flicker can thus be minimized. This was experimentally tested on a single-phase model and the results obtained were very satisfying. Due to laboratory facilities, the three-phase testing was not performed