共查询到20条相似文献,搜索用时 31 毫秒
1.
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. 相似文献
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A single-phase controlled-current PWM rectifier 总被引:9,自引:0,他引:9
The analysis and test results are given for an experimental single-phase controlled-current PWM (pulse-width-modulated) rectifier that operates at unity power factor with near sinusoidal current waveform and that has power reversal capability. The twice-line-frequency AC power is identified as a source of voltage harmonics in the DC link. The harmonics enter into the voltage regulation feedback loop to distort the AC current waveform. These undesirable harmonics can be removed by a low-pass filter. It is noted that the overall design must address the possibility of instability due to the low-pass filter in the feedback path 相似文献
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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 相似文献
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基于智能整流技术的电网电流谐波补偿方法研究 总被引:1,自引:0,他引:1
目前用于电网电流谐波补偿的电器设备,主要以PWM整流器为主。基于PWM整流器的电源产品只能被动地减小自身向电网输出的谐波电流,而对电网中业已存在的电流谐波污染束手无策。为了解决电网中电流谐波污染以及相关联的电压波形失真问题,采用基于SRM(智能整流模块)技术对电网电流谐波进行补偿。仿真结果表明,基于SRM的电力电子装置在从电网吸取电流并在向负载供电的同时,还能对电网电压的波形进行补偿,使电网电压波形接近正弦波形。 相似文献
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This paper describes the conception and analysis of a unidirectional hybrid three-phase rectifier suitable for medium- and high-power applications. The rectifier is composed of a single-switch diode bridge boost-type rectifier in parallel with a pulsewidth modulation (PWM) three-phase unidirectional boost rectifier. The objective is to obtain a structure capable of providing sinusoidal input currents with low harmonic distortion and dc output voltage regulation. The diode rectifier operates at low frequency and has a higher output power rating. Therefore, the PWM unidirectional rectifier is designed to operate with a small power rating and at a high switching frequency. The total harmonic distortion of the proposed structure varies between 0% and 32%, depending only on the amount of power processed by the PWM three-phase unidirectional rectifier. The rectifier topology conception, principle of operation, control scheme, and simulation and experimental results of a 20-kW laboratory prototype are also presented in this paper. 相似文献
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《Power Electronics, IEEE Transactions on》2009,24(1):75-84
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It is well known that a PWM-controlled rectifier can offer advantages of reduced low-order harmonics and unity input power factor when compared to a conventional thyristor converter. However, theoretically optimum PWM strategies are often difficult to implement physically or are not easily extended to regenerative operation. The authors propose an alternative PWM strategy based on AC-AC matrix converter theory, which generates only high-order switching harmonics, presents a unity power factor load to the supply, implicitly extends to regeneration (and operation with a center tapped DC output), and is feasible to physically implement for real-time output voltage control. Both the theory and physical simulation results are presented 相似文献
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《Power Electronics, IEEE Transactions on》2008,23(4):1679-1691
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Bor-Ren Lin Shuh-Chuan Tsay Mu-Shan Liao 《International Journal of Electronics》2013,100(11):1189-1204
A simple strategy and low cost control for the switching mode rectifier to work simultaneously as a power factor corrector and an active power filter (APF) to reduce current harmonics drawn from the nonlinear load are analysed and presented in this paper. The principal component of the control circuit is an Intel 80196MC microcontroller that performs the dc bus voltage and line current control. The sliding mode control is used in the current loop to achieve fast line current dynamics. The source currents only are measured in the proposed control scheme instead of both the source and load currents needed in the conventional control approach. A simple proportional-integral control is adopted in the voltage loop to achieve slow dc bus dynamics. The proposed control strategy can achieve a high power factor and low current harmonics. No dedicated APF is needed in the proposed control strategy. To demonstrate the effectiveness of the integrated power factor compensator for elimination of reactive power and current harmonics, software simulation and hardware tests are performed. 相似文献
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Bor-Ren Lin 《International Journal of Electronics》2013,100(2):225-247
A novel three-level pulsewidth modulation (PWM) rectifier/inverter is proposed: this single-phase three-level rectifier with power factor correction and current harmonic reduction is proposed to improve power quality. A three-phase three-level neutral point clamped (NPC) inverter is adopted to reduce the harmonic content of the inverter output voltages and currents. In the adopted rectifier, a switching mode rectifier with two AC power switches is adopted to draw a sinusoidal line current in phase with mains voltage. The switching functions of the power switches are based on a look-up table. To achieve a balanced DC-link capacitor voltage, a capacitor voltage compensator is employed. In the NPC inverter, the three-level PWM techniques based on the sine-triangle PWM and space vector modulation are used to reduce the voltage harmonics and to drive an induction motor. The advantages of the adopted th-ree-level rectifier/inverter are (1) the blocking voltage of power devices (T1, T2, Sa1-Sc4) is clamped to half of the DC-link voltage, (2) low conduction loss with low conduction resistance due to low voltage stress, (3) low electromagnetic interference, and (4) low voltage harmonics in the inverter output. Based on the proposed control strategy, the rectifier can draw a high power factor line current and achieve two balance capacitor voltages. The current harmonics generated from the adopted rectifier can meet the international requirements. Finally, the proposed control algorithm is illustrated through experimental results based on the laboratory prototype. 相似文献
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三电平PWM整流器多采用电压控制外环和电流控制内环组成的双闲环控制系统。电压外环的作用是根据直流电压Udc的大小决定三电平PWM整流器输出功率的大小和方向以及三相电流的给定信号。电流内环的作用是使整流器的实际输入电流能够跟踪电流给定,实现单位功率因数或功率因数可变。文中主要研究了三电平PWM整流器的系统设计,并进行了仿真。结果表明,所设计的双闭环系统具有良好的抗扰动性能,动态响应也得到了明显的改善。 相似文献
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Neacsu D.O. Wagner E. Borowy B.S. 《Industrial Electronics, IEEE Transactions on》2008,55(4):1628-1636
A solution for high current applications consists of paralleling power stages of lower power. Given the complexity of these systems, a comprehensive computer-based analysis is required before physical implementation. This paper presents a simulation benchmark for selection of the pulsewidth modulation (PWM) algorithms used to control interleaved three-and four-wire three-phase power inverters. The analysis considers the resulting phase current harmonics, dc link current harmonics, neutral point voltage, and inter converter circulation currents. Analytical aspects of different current control structures used within interleaved power electronics systems and effects of selecting various PWM algorithms are revealed for both the three-wire and the four-wire structure. Finally, analysis of the DSP implementation for different practical solutions is shown. 相似文献
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Guanghai Gong Heldwein M.L. Drofenik U. Minibock J. Mino K. Kolar J.W. 《Industrial Electronics, IEEE Transactions on》2005,52(3):727-737
A passive 12-pulse rectifier system, a two-level, and a three-level active three-phase pulsewidth-modulation (PWM) rectifier system are analyzed for supplying the dc-voltage link of a 5-kW variable-speed hydraulic pump drive of an electro-hydrostatic actuator to be employed in future More Electric Aircraft. Weight, volume, and efficiency of the concepts are compared for an input phase voltage range of 98-132 V and an input frequency range of 400-800 Hz. The 12-pulse system shows advantages concerning volume, efficiency, and complexity but is characterized by a high system weight. Accordingly, the three-level PWM rectifier is identified as the most advantageous solution. Finally, a novel extension of the 12-pulse rectifier system by turn-off power semiconductors is proposed which allows a control of the output voltage and, therefore, eliminates the dependency on the mains and load condition which constitutes a main drawback of the passive concept. 相似文献
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针对微型燃气轮机(微燃机)发电系统的特点,建立了以电压型双向脉宽调制(PwM)变换器为功率变换装置的起动/发电控制模型。微型燃气轮机发电系统起动时,采用矢量控制;发电运行时,采用电压外环电流内环的双环PWM整流控制。仿真实验结果表明:起动时,高速永磁同步电机(PMSG)采用矢量控制比速度开环控制性能更优,减少了起动时间,满足快速起动的要求;发电运行时,与二极管整流相比,PWM整流能使交流侧电流跟踪发电机的感应电动势,功率因数约为1,降低了发电机侧的电流谐波,即减少了谐波热。同时保证了发电机在一定宽速范围内,输出直流电压稳定,并且在起动一发电过渡转换过程中,直流母线电压降落后,快速恢复为稳定值,满足平滑转换的要求。 相似文献
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This study concerns the modeling and control of a pulse-width-modulated (PWM) rectifier in the case of network variations. The aim is to limit and stabilize variations of DC output voltage and line currents in such circumstances. Network variations can result in costly damage to power converters and their loads but a power converter such as the PWM rectifier, using cascade digital control, offers many capabilities to stabilize the system with optimized control. A generalized model of the PWM rectifier is first presented using the Clarke notation in order to separate the positive and negative sequences. The model is also extended to the harmonics. The cases of harmonic disturbance and an unbalanced network are then analyzed and an optimized regulation is presented for the latter case, validating the generalized model. Experimental results are proposed. The line current compensation loop method coupled with identification of network parameters offers a good solution to stabilize the PWM rectifier in an unbalanced network 相似文献
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This paper describes a 6.6-kV adjustable-speed motor drive for pumps and blowers without transformer. The power conversion system consists of a front-end diode rectifier, a five-level diode-clamped pulsewidth modulation (PWM) inverter with a voltage balancing circuit, and a hybrid active filter for harmonic-current mitigation of the diode rectifier. The control of the inverter is characterized by superimposing a third-harmonic zero-sequence voltage on each of the three-phase reference voltages to achieve the so-called overmodulation and reduce the switching stress of insulated gate bipolar transistors (IGBTs). A 200-V 5.5-kW downscale model is designed, constructed, and tested with focus on the five-level PWM inverter and the voltage balancing circuit. Experimental results obtained from the 200-V downscale model verify the viability and effectiveness of the 6.6-kV adjustable-speed motor drive, showing that the four split dc capacitor voltages are well balanced in all the operating conditions and that the switching stress of the IGBTs is reduced at low modulation indexes. 相似文献
18.
《Industrial Electronics, IEEE Transactions on》2009,56(7):2420-2430
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A Modular Strategy for Control and Voltage Balancing of Cascaded H-Bridge Rectifiers 总被引:1,自引:0,他引:1
《Power Electronics, IEEE Transactions on》2008,23(5):2428-2442
20.
This paper presents a new control strategy to improve the performance of the PWM boost type rectifier when operating under an unbalanced supply. An analytical solution for harmonic elimination under unbalanced input voltages is obtained resulting in a smooth (constant) power flow from AC to DC side in spite of the unbalanced voltage condition. Based on the analysis of the open loop configuration, a closed loop control solution is proposed. Simulation results show excellent response and stable operation of the new rectifier control algorithm. A laboratory prototype has been designed to verify the discussions and analyses done in this paper. Theoretical and experimental results show excellent agreement. Elimination of the possibility of low order AC and DC side harmonics due to unbalance is expected to materially affect the cost of DC link capacitor and AC side filter. The proposed method is particularly useful in applications where the large second harmonic at the DC link may have a severe impact on system stability of multiply connected converters on a common link 相似文献