龚氏桥全可控整流电路

论述桥式和全波相结合的单相可控整流电路,该电路突破可控整流电路最大输出电流点和最佳功率因数点只能在最高输出电压点上的传统,可在低电压输出电流达到桥式电路的2倍以上。桥全可控整流电路只要在桥式电路上增加一只整流或可控整流器件即可获得,不但吸取全波和桥式二类经典电路的优点,而且把二类电路包含在内,成为性能最好、电路数量最多、最高形式的单相可控整流电路。     

航空机电作动器的混合整流全状态反馈控制

研究了一种适用于多电飞机供电系统的新型混合整流电路,并针对航空机电作动器负载特殊的用电特性,提出了一种基于全状态反馈的混合整流控制方法,在保证整流效果的同时,解决了负载功率短时大范围变化引起的直流电压不稳定问题。这种新型混合整流电路将二极管整流电路和脉宽调制(PWM)整流电路并联输出接负载,两者共同承担有功功率且比例可控,通过适当控制PWM电路达到网侧低谐波的目的,且当负载制动时,能量可以回馈交流侧电网。建立了混合整流器的线性化全状态数学模型,设计了基于线性二次型(LQR)最优化理论的全状态反馈控制策略。通过在MATLAB/Simulink下的建模与仿真,比较了全状态反馈控制方法与传统三状态反馈控制方法,并在机电作动器样机上进行了实验验证。仿真和实验结果表明,采用全状态反馈控制的新型混合整流方案对于功率大范围变化负载具有更好的控制性能。     

能量反馈型电子负载的研究

为了能量反馈型电子负载能够连续稳定运行,采用STM32单片机作为控制器,通过对系统分析,提出较为实用的控制模型。经过Simulink仿真,采用滞环算法和PID算法控制系统,可以得到满意的效果。实验结果表明:整流级的电流相位可以滞后或超前其电压相位任何角度,逆变级工作在功率因数是1的逆变状态,整个系统可以稳定连续运行。系统的控制模型正确,控制方案可行。     

测控雷达伺服系统整流电路的建模与仿真

电力电子整流电路是测控雷达伺服系统的重要组成部分。某型测控雷达采用了三相零式反并联可逆整流电路结构。分析了整流电路可逆运行的工作原理以及晶闸管触发电路的控制方式,利用MATLAB/Simulink的建模功能,建立了触发脉冲产生电路和整流电路的模型,仿真得出系统可逆运行时电机的工作状态以及整流电路输出电压波形。仿真结果显示,此整流电路可以实现电机的四象限运行,所建模型正确。利用该模型可以对测控雷达伺服系统的分析和设计起到很好的辅助作用。     

基于SVPWM的高功率因数整流器研究

介绍了三相电压型PWM整流器的数学模型和空间矢量PWM(SVPWM)控制技术,并根据设计要求完成了主电路中相关参数的设计。实验发现,采用SVPWM电流控制技术能够使网侧电压与电流同相位,表明电压型PWM整流器实现了高功率因数整流。     

单相PWM整流电路控制方法及仿真分析

分析单相PWM整流电路的结构、工作原理和控制方法,通过选择适当的工作模式和工作时序,可使PWM整流电路输出直流电压稳定。将正弦脉宽调制技术应用于PWM整流电路,使其交流侧输入电流非常接近正弦波,且与输入电压同相位。同时调节交流侧电流的大小和相位,使能量在交流侧和直流侧双向流动。在建立基于Simu-link7.6的仿真模型基础上,通过分析PWM整流电路各处电压、电流波形,验证其控制方法及仿真设计的正确性。     

校正开关型电源的功率因数

对于复杂的开关型电源设计者来说,想获得很高的功率因数是比较困难的。如果电源电路的功率因数很低,电源就可能达不到联邦通讯委员会关于电磁容性方面的规定。另外,由于较底的功率因数造成很大的输入尖峰电流:从而降低了电路的可靠性现在,电源设计者应用两种新出现的集成电路,可以较容易地解决这一问题:在应用功率 MOS 管的功率转换电路中,用新型的集成控制电路来校正提高电源的功率因数、并且使电源的输入电压有很宽的调节范围.     

多VIENNA级联型整流电路的协调控制

针对级联式高压整流电路的控制问题,采用多个VIENNA整流器级联构成高压直流系统,设计了主电路拓扑与双闭环控制器,并提出一种多VIENNA整流器电压平衡的协调控制策略。通过仿真试验,验证了双闭环级联型VIENNA高压整流电路的稳定性及其协调控制的正确性。     

小束斑电子束脉冲轰击偏压电源的研制

为了获得一种性价比较高的电子束表面处理技术,采用定频调压电路,研制出一种新型偏压脉冲电源。这种电源由偏压主电路拓扑、偏压变压器和偏压整流滤波电路组成,其中偏压主电路由偏压基值发生电路和偏压脉冲发生电路组成。偏压基值发生电路控制偏压脉冲基值,偏压脉冲发生电路控制偏压脉冲频率和占空比。脉冲偏压电源的脉冲基值、脉冲频率、占空比均连续可调,相应实现脉冲束流的幅值、束流频率和占空比的调节。检测分析了脉冲偏压电源的输出电压波形,带载时的输出束流波形,并观察分析了电子束轰击后钨合金组织变化规律。结果表明所研制的脉冲偏压电源输出电压稳定、可调性好,能满足小束斑脉冲电子束轰击工艺的要求。     

三相桥式全控整流电路反相序工作的仿真

三相桥式全控整流电路反相序工作是调试中常见状态。为了对此状态下整流电路的工作过程进行分析,采用Matlab/simulink软件对此进行了仿真。结果表明,在控制角(α)从0°到180°的增加过程中,反相序输出电压波形出现了反复,输出电压平均值(Ud)出现两次最大值。通过分析反相序对触发信号的影响,对此现象进行了解释,并得到Ud的计算公式。     

Half-bridge neutral point diode clamped rectifier for power factor correction

A high power factor rectifier based on neutral point clamped scheme is proposed. The voltage stress of each power semiconductor of the adopted rectifier is equal to the half dc bus voltage instead of full dc link voltage in the conventional switching mode rectifier. The control signals of the power switches are derived from the dc link voltage balance compensator, line current controller, and dc link voltage regulator. The hysteresis current control scheme is employed to draw a clean sinusoidal line current, high input power factor, regulated dc link voltage, and balance capacitor voltages. Three voltage levels are generated on the ac terminal of the adopted rectifier. To verify the proposed operation scheme, performance characteristics are given by the experimental results.     

Novel single-phase AC/DC converter with two PWM control schemes

A novel single-phase AC/DC converter with two pulsewidth modulation (PWM) schemes is proposed to draw a sinusoidal line current with nearly unity power factor, achieve balanced neutral point voltage and regulate the DC bus voltage. With the aid of neutral point clamped scheme, a three-level voltage pattern is generated on the AC side of the proposed rectifier. To track the tine current command derived from a voltage controller and a phase-locked loop circuit, a hysteresis current control scheme is used in the inner loop control. A capacitor voltage compensator is employed to achieve the balanced neutral point voltage. To investigate the effectiveness of the proposed control scheme, the simulation and experimental results based on a laboratory prototype circuit are performed.     

Control technique for high power factor multilevel rectifier

Three control techniques for a high power factor multilevel pulsewidth modulation (PWM) rectifier are proposed. The proposed rectifier is based on series connection of full-bridge cell to achieve a high power factor, low current distortion, low voltage stress of power semiconductors and two balanced output voltages. The look-up table is used in the proposed control schemes to reduce the hardware circuit. A capacitor voltage compensator is used to balance two dc capacitor voltages in order to obtain high quality PWM voltage pattern. Based on the proposed control schemes, two-level or three-level PWM pattern can be generated on the ac side of the adopted rectifier. The proposed techniques for a high power factor multilevel rectifier illustrate its validity and effectiveness through the respective simulations and experiments. According to the measured results, the current harmonics drawn from the mains meet the International Electrotechnical Commission (IEC) 1000-3-2 limits     

Single-phase three-level rectifier and random PWM inverter drives

A novel ac/dc/ac converter topology with three-level pulsewidth modulated (PWM) scheme for the single-phase ac/dc rectifier and random PWM scheme for ac drives is proposed. In order to improve the power quality in the single-phase rectifier, a ROM-based (read-only memory) control scheme, based on hysteresis current comparator, region detector, and capacitor compensator, is used to achieve a sinusoidal line current with low current distortion. The control scheme of the adopted three-level rectifier is easy to implement. The blocking voltage of power switches is clamped to half of the dc bus voltage. To reduce the mechanical vibration from an induction motor, random pulse position PWM scheme is adopted to spread the harmonics in a wide frequency range which results in the reduction of torque pulsation in the ac motor drives. Simulation and experimental results based on the laboratory prototype circuit are presented to verify the proposed control scheme     

变速恒频电源闭环控制系统设计

 本文讨论了变速恒频电源闭环控制电路的设计。闭环控制电路的目的除保证变速恒频电源达到所要求的动、静态性能指标外,对其中交交变频器输出中存在的直流、次谐波及其它谐波分量要有强的抑制能力,以减小主电路滤波器的体积重量。为此,文中提出了采用微分反馈并联校正、比例积分串联校正及电压调节的闭环控制系统方案,并进行了一系列实验研究和验证。     

Implementation of a single-phase AC/AC converter based on neutral-point-clamped topology

A single-phase ac/ac converter based on neutral-point-clamped scheme is proposed to perform unity input power factor and to provide a stable ac voltage to the critical loads. The ac/dc rectifier part is controlled to generate a unipolar pulsewidth modulation (PWM) waveform on the ac terminal by using four power switches with voltage stress of half the dc-link voltage. The carrier-based current control scheme is employed in the inner control loop to track the line current command. To regulate the dc bus voltage, a proportional-integral (PI) control is adopted in the outer control loop. The dc/ac inverter part of the system with four power switches is employed to generate a stable and clean sinusoidal output voltage to the critical load. The instantaneous current control scheme is used to track the output voltage command. To verify the effectiveness of the proposed control algorithm, the simulation and experimental results based on a laboratory prototype were implemented and discussed.     

基于DSC整流器和双闭环PR逆变器的模块化中频静变电源

与传统中频电源相比,模块化中频静变电源具有选用灵活、可靠性高、冗余性好、便于系统维护等优点。中频静变电源整流器在控制母线电压稳定的同时还要实现单位功率因数控制。为此,具体分析了双电流环控制策略,给出了双电流环控制器中电压电流正负序分离原理和双dq锁相环的具体实现方法,即延时信号抵消(DSC)和双闭环准比例谐振(PR)。针对逆变器输出电压基波无差跟踪困难、谐波含量高等问题,采用双闭环多重准PR控制策略,实现中频电压的稳定输出。仿真和试验结果表明,双电流环控制器能同时实现母线电压稳定和单位功率因数控制,采用双闭环多重准PR控制策略的中频逆变器能够输出稳定的中频交流电压。     

Space vector modulation strategy for an eight-switch three-phase NPC converter

A three-phase neutral point clamped (NPC) converter is presented for power factor correction and dc-link voltage regulation. A simplified space vector pulsewidth modulation scheme (SVPWM) is adopted to track line current commands. Using a simplified SVPWM algorithm, the calculated time for the time duration of voltage vector is reduced. The adopted NPC converter has less power switches compared with the conventional three-level NPC converter. Only eight power switches and four clamping diodes with voltage stress of half the dc bus voltage are used in the circuit configuration. Based on the proposed control algorithm, a reference voltage vector is generated on the ac terminal for drawing the sinusoidal line currents with unity power factor. Computer simulation and experimental results based on a laboratory prototype are presented to verify the validity and effectiveness of the proposed control strategy.