逆变桥无死区控制技术研究

分析了逆变器的死区效应,给出了桥式逆变器无死区控制方案。根据电流极性将桥臂等效为2个开关单元,无需设置死区时间。采用桥臂反并联二极管导通方法检测桥臂输出电流方向,无需电流传感器,降低了成本。采用简单的模拟电路设计了无死区控制的逻辑电路,以半桥逆变器为例进行了实验研究。实验结果表明,该控制方案可以明显改善逆变器的输出波形,提高直流电压利用率,开关管驱动信号只在半个基波周期内有效,开关损耗显著降低,有很好的实用价值。     

3H桥开关次数均衡死区消除SVPWM

针对死区时间引起H桥拓扑各桥臂输出电压波形偏离给定参考电压的问题，根据一个开关周期内调制波与输出电流极性提出了具有12种导通状态的新型开关方式。基于新型开关方式提出了3H桥开关次数均匀分布死区消除SVPWM方案。以三相感应电机作为负载，推导出采用死区消除SVPWM后，在输出电流过零处工频与高频工作桥臂具有的天然死区时间。MCU输出各桥臂上下开关管相位互差180°SVPWM信号以及表征调制波与输出电流极性的电平信号，而后信号经FPGA处理后获得死区消除SVPWM信号。实验结果中给出了在相同参考电压下，采用死区消除SVPWM时输出电压最大偏离给定电压在1.3%左右，而采用有死区SVPWM时最大偏离给定电压在23%左右。由此可见，由MCU与FPGA相结合的数字系统能够很好地实现开关次数均衡死区消除SVPWM策略。     

基于TMS320F2812控制的高频逆变死区时间补偿方法研究

为了防止逆变桥中同一个变流臂上下两组元件同时导通而引起直流侧电源的短路,要求导通上下桥臂的PWM互不重叠,就此提出了一种基于TMS320F2812控制的高频逆变死区时间补偿方法。通过实验表明,该补偿方法能合理地控制死区时间,避免同一个变流臂上的上下两组元件同时导通,成功地解决了逆变电路输出电压失真的问题,操作简单、实用性强,有广阔的应用前景。     

三相单级全桥PFC变换器输入电流死区分析与补偿

研究一种三相单级全桥结构功率因数校正(PFC)变换器,该变换器工作于电感电流断续模式(DCM),可同时实现PFC、输入/输出侧电气隔离以及输出电压调节.通过对该变换器理想和非理想条件下等效电路的分析,发现由于主电路中各开关管和二极管存在导通压降,当输入电压低于主电路压降时,导通相电流将出现死区,该死区随着输入电压幅值的降低而增大.结合电路的工作原理,提出了一种抑制电流死区的补偿电路.补偿电路由6个小功率开关管和电阻构成,通过相应的控制策略,当输入电压最小的一相电压低于主电路压降时.该相电流通过补偿电路构成回路,消除电流死区.仿真与实验结果证明了理论分析的正确性.     

三相并网型逆变器死区补偿方法

为防止逆变器上下桥臂发生短路,需要在IGBT的驱动信号中设置死区时间。由于死区时间的存在会改变逆变器直流侧的电压输出,导致网侧电流输出畸变,将死区效应所造成的电压扰动矢量进行前馈补偿,根据并网型逆变器的电流特点,提出了一种用低通滤波器与加权滤波的方法获取正序电流的方法,用以判断电压补偿矢量。通过实验验证了该方法的准确性和有效性。     

基于Si9122A的同步整流输出DC/DC变换器

研制了半桥结构的DC/DC变换器.采用带同步整流驱动输出的新型半桥控制芯片Si9122A实现了对变换器中初级开关管和次级同步整流管的PWM控制.该变换器电路结构简洁,控制调整方便.由于输出整流电路中采用低导通电阻的同步整流MOSFET替代了肖特基二极管,芯片自带同步整流管驱动信号,解决了自驱动方式信号差和外驱动方式电路复杂的问题.最后给出了实验结果.     

死区对电压型逆变器输出误差的影响及其补偿

针对电压型逆变器的死区效应,分析了死区对逆变器输出电压谐波和电流的影响,提出一种基于功率导通时间实时检测的死区补偿和电机相电压检测方法.为避免电流过零点的直接检测或间接预估,设计硬件电路直接检测功率管的导通时间,得到逆变器的实际死区时间,并在软件中进行补偿,同时得到电机实际的相电压.采用该方法得到的死区时间反映了开关器件导通和关断时间受结温和导通电流影响的特性,最后对上述方法进行了实验验证.     

一种适用于GaN基电机驱动器的新型死区自适应控制方法EI北大核心CSCD

设置死区时间是为了防止桥臂电路上下管直通问题,保证电机驱动器的可靠性。氮化镓(gallium nitride,GaN)基电机驱动器对死区设置较为敏感,死区时间过长会导致GaN器件反向导通损耗过高及电机驱动器输出波形畸变,过短则会造成输出电容损耗及高电流尖峰。该文对第一及第二死区时间的影响进行分类讨论,分析得出两种死区时间的优化原则,并基于此提出一种新型死区自适应控制方法。这种方法无需添加额外硬件电路,可以在消除输出电容损耗及电流尖峰的同时减小反向导通损耗,提高效率,并有效降低电机驱动器负载电流的总谐波失真,提高电机运行稳定性。仿真和实验验证新型死区自适应控制方法的有效性,且其在重载及高开关频率状态下较传统死区设置方法具有明显优势。     

智能化IGBT驱动电路研究

研究并设计了一种基于复杂可编程逻辑器件(CPLD)的智能化IGBT驱动电路.该电路由CPLD实现各种控制、保护逻辑.驱动电路的高、低电平驱动方式可通过改写CPLD中VHDL源代码来实现.同时,该电路可以选择两路直接驱动和桥臂互补驱动两种工作模式.电路具有开通盲区设置,死区时间设置功能,短路保护运用软降栅压结合软关断技术,软降栅压时间,软关断斜率可通过外接电路自由整定.电路本身自带隔离驱动电源.试验证明该电路具有良好的驱动及保护能力.     

PWM逆变器死区效应的逻辑补偿电路的设计

在由ＰＷＭ调制的功率转换器中,为防止上下同一桥臂的２个功率管发生直通短路而加入几个微秒死区时间,但这样会引起输出波形的畸变,笔者设计了一种针对死区效的逻辑补偿电路,可以应用于离线控制的ＰＷＭ逆变器中。     

一种适合感应加热电源的IGBT驱动电路

为满足感应加热电源对绝缘栅双极晶体管(Insulated Gate Bipolar Transistor,简称IGBT)驱动和保护功能的要求,采用可驱动大功率MOSFET和IGBT的IXDD414CI芯片作为主驱动元件,设计了一种驱动电路.该电路具有降栅压软关断和软关断封锁脉冲的保护功能,并能输出报警信号;其工作频率高,延迟时间小,驱动能力强,保护功能完善,因而非常适合用于大功率感应加热电源.详述了驱动电路构成和工作原理,给出了实验结果.     

Implementation of a Soft Switching Converter with High Input Voltage

This paper presents an interleaved zero voltage switching (ZVS) DC/DC converter with high input voltage applications. In order to reduce the voltage stress of MOSFETs, two half‐bridge zeta converters are connected in series at high voltage side. Thus, the voltage stress of MOSFETs can be clamped at one‐half of input voltage. Asymmetric pulse‐width modulation (APWM) is adopted to control power switches. With the resonant behavior by the leakage inductance of transformer and the output capacitance of MOSFET at the transition interval, MOSFETs can be turned on at ZVS. For each half‐bridge zeta converter, two series transformers are connected in series at the primary side and in parallel at the secondary side in order to reduce the current stress of secondary windings for high load current applications. Interleaved PWM scheme is used to control two half‐bridge converters in order to reduce the size of output filter inductor and capacitor due to the partial ripple current cancellation. Experimental results, taken from a laboratory prototype rated at 1 kW, are presented to demonstrate the converter performance. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis and Implementation of an Interleaved ZVS Converter with High Input Voltage

An interleaved half‐bridge converter is presented for high input voltage application. The features of the proposed converter are zero voltage switching (ZVS) turn‐on for all active switches, ripple current reduction at output side, load current sharing and load voltage regulation. Two half‐bridge converters connected in series and two split capacitors are used to limit the voltage stress of each power switch at one‐half of input DC bus voltage. Thus, active switches with low voltage stress can be used at high input voltage application. On the other hand, the output sides of two half‐bridge converters are connected in parallel to share the load current and reduce the current stresses of the secondary windings and the rectifier diodes. Since two half‐bridge converters are operated with interleaved pulse‐width modulation (PWM), the output ripple current can partially cancel each other such that the resultant ripple current at output side is reduced and the size of output inductors can be reduced. In each half‐bridge converter, asymmetrical PWM scheme is used to regulate the output voltage. Based on the resonant behavior by the output capacitance of MOSFETs and the leakage inductance (or external inductance) of transformers, active switches can be turned on at ZVS during the transition interval. Thus, the switching losses of power MOSFETs are reduced. The proposed converter can be applied for high input voltage applications such as three‐phase 380‐V utility system. Finally, experiments based on a laboratory prototype with 960‐W rated power are provided to demonstrate the performance of proposed converter. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis and implementation of a soft switching DC/DC converter with three asymmetric PWM circuits

This paper presents a soft switching converter with three buck‐type active clamp circuits (or asymmetric half‐bridge circuits) to achieve the functions of the low power rating on the transformers and power semiconductors and low current rating on the rectifier diodes and output inductors. Three half‐bridge circuits are stacked at the high voltage side to reduce the voltage stress of each power switch at one‐half of input voltage and connected in parallel at the low voltage side to share load current and reduce the current rating on each magnetic component and the rectifier diode. Thus, the size of the output chokes is reduced. In each half‐bridge converter, the asymmetric pulse‐width modulation is adopted to control power switches. Power MOSFETs can be turned on with zero voltage during the transition interval due to the resonant behavior by the output capacitance of MOSFETs and the leakage inductance (or external inductance) of transformers. Experiments based on a laboratory prototype with 1 kW rated power are provided to demonstrate the performance of proposed converter. Copyright © 2012 John Wiley & Sons, Ltd.     

五相双绕组感应发电机励磁控制系统硬件设计与实现

本文研究了一种五相双绕组感应发电机励磁控制系统的硬件设计与实现方法。该发电机的转子为笼型,其定子上有两套五相绕组:一套是控制绕组,接有励磁变换器;另一套是功率绕组,经整流输出直流电能。励磁变换器由以绝缘栅双极型晶体管(IGBT)模块为基础的主电路、驱动电路、数学信号处理电路、采样调理电路、保护电路等部分组成。励磁控制器向发电机提供所需的可变励磁无功,控制发电机励磁,从而实现对输出电压的控制。     

混合集成IGBT驱动器的实验与分析

QP12W05S-37(A)是一种自带隔离电源的混合集成型IGBT驱动器,作为隔离放大器,可应用于任何需要栅极放大驱动的场合.通过光耦为功率开关器件提供必要的初/次级之间电气隔离.并且采用检测IGBT的集电极欠饱和压降的方法来实现过流及短路保护功能.文中主要分析IGBT的驱动和保护问题,详细介绍混合集成IGBT驱动器Q...     

一种桥式拓扑结构下MOSFET高速驱动电路

针对桥式拓扑中MOSFET因栅极驱动信号振荡产生的桥臂直通问题,分析了振荡与驱动电路各参数之间的关系,并设计了一种驱动电路。该电路结构简单、工作频率高、延迟时间小、抗干扰能力强,因而非常适用于高频感应加热电源。理论分析和实验结果表明,经过改进的驱动电路解决了驱动信号振荡问题,从而保证了MOSFET在高速应用场合的可靠运行。所设计的电路已应用于530kHz/2.5kW感应加热电源,实验波形证明了其合理性和有效性。     

Hybrid DC–DC converter with high efficiency,wide ZVS range,and less output inductance

In this paper, a new soft switching direct current (DC)–DC converter with low circulating current, wide zero voltage switching range, and reduced output inductor is presented for electric vehicle or plug‐in hybrid electric vehicle battery charger application. The proposed high‐frequency link DC–DC converter includes two resonant circuits and one full‐bridge phase‐shift pulse‐width modulation circuit with shared power switches in leading and lagging legs. Series resonant converters are operated at fixed switching frequency to extend the zero voltage switching range of power switches. Passive snubber circuit using one clamp capacitor and two rectifier diodes at the secondary side is adopted to reduce the primary current of full‐bridge converter to zero during the freewheeling interval. Hence, the circulating current on the primary side is eliminated in the proposed converter. In the same time, the voltage across the output inductor is also decreased so that the output inductance can be reduced compared with the output inductance in conventional full‐bridge converter. Finally, experiments are presented for a 1.33‐kW prototype circuit converting 380 V input to an output voltage of 300–420 V/3.5 A for battery charger applications. Copyright © 2015 John Wiley & Sons, Ltd.     

后级调整技术在多路输出反激电路中的运用

详细分析了一种运用了后极调整技术的多路输出反激变流器的工作原理.和磁开关不同,该变流器在主反馈输出上没有最小输出负载的要求,从而电路可以达到更高的效率.同时文中还给出了该电路的一个实用的小信号模型.实验结果验证了该变流器的特点.     

液体酸度测量

在利用传感器进行液体酸度测量的时候,往往由于传感器电极本身的差异,或是由于放大电路元器件的精确度的不同而引起的系统误差总是不可避免的,同时,温度对于输出信号的影响也是不可忽视的。本文分别从软硬件2个方面来解决由于系统误差而引起的输出信号的飘移问题。文中首先简要介绍了pH值电极的工作原理,然后给出了2种软件标定和温度补偿方法,最后提供了一个pH值电极信号测量的后置放大电路的设计方案,并重点指出了在硬件电路实现时的一些关键问题,特别是第一级运放电路元件的选型问题。