电抗器IGBT电路实现原理

通过引用零值器与泛值器的概念设计无铁磁材料电抗器,将绝缘栅双极晶体管(IG-BT)器件用零值器与泛值器等效表示,用零值器与泛值器设计频率固定的电压反向型和电流反向型电抗器。根据IGBT器件等效成零值器与泛值器总是连接在一起的特点,将零值器与泛值器设计的电压反向型和电流反向型电抗器进行等效变换,最后用IGBT器件变换零值器与泛值器,得到了IGBT电路实现频率固定的电压反向型和电流反向型电抗器原理电路。     

IGBT电路实现三相可控电抗器电压不对称运行分析

为了探索利用IGBT实现的非铁磁三相可控电抗器在实际工程中的运行状况,对利用IGBT实现的三相非铁磁性电抗器电路进行了基于Multisim软件的仿真分析。通过改变仿真电路的参数,探索IGBT实现的非铁磁三相可控电抗器的可控范围,并模拟实际工程中电力系统的不对称运行情况下IGBT实现的非铁磁三相可控电抗器通的输入电流和输入电压的波形,分析该电抗器在不对称工况下的运行状况。结合了工程实践中的实际应用,分析表明此电抗器能够满足现代电力工业对电抗器的要求。     

低压三相电抗器IGBT电路实现

主要针对低压三相电抗器的IGBT电路实现的问题进行了仿真分析。首先针对三相四线制低压电抗器IGBT电路实现问题进行分析,运用Multisim11.0软件进行电路仿真分析,仿真结果表明,接入IGBT电路实现的电抗器可以稳定运行,各相电流幅值误差在1%以内,相位误差在0.4°以内。然后,对三相三线制低压电抗器IGBT电路实现问题用相同的方法进行了分析,仿真结果表明,电路可以稳定运行,电流幅值误差在0.2%以内,相位误差在2以内。通过两项仿真实验,证明了低压电抗器IGBT电路实现的可行性,为其应用推广提供了理论上的依据。     

低应力全桥型串联谐振直流环节变流器

提出了串联谐振直流环节节流器的新拓扑结构,在取消直流大电感并为开关器件提供零电流开关条件的同时,有效地降低了开关器件的电压电流应力,可采用与同等容量下非谐振型交流器相同等级的开关器件。介绍了电路工作原理,分析了器件的电压电流应力,并给出了仿真及实验波形。     

一种高效倍压升压型软开关功率因数校正电路

提出一种高效零电压转换倍压升压型变换器的功率因数校正电路。新型软开关技术可以实现整流器主开关和无源开关零电压转换,而辅助开关零电流通断。所述软开关技术没有增加电路主开关的电压和电流应力。由于所用电路主电路导通流经更少的半导体功率器件,因此具有较少的器件导通损耗。该电路结构适合低压输入和中高功率应用场合。计算机仿真和实验样机验证了理论预期。该样机实现转换效率高达97%,功率因数为0.992。     

无桥拓扑有源PFC的理论和仿真研究

针对传统有源Boost-PFC的功率开关器件开关导通损耗大,承受较高的电压、电流和热应力的不足之处,提出了一种新型的无桥有源PFC电路(BLPFC)结构.该电路用两个IGBT取代了传统整流桥下桥臂的两个整流二极管,并采用双闭环平均电流控制策略,使之具有传统PFC提高功率因数和降低电网谐波的特点,又具有提高系统开关器件效率,降低系统损耗,发热和成本的优点.利用Matlab/Simulink的SimPowerSystems工具包对设计的BLPFC电路进行仿真,仿真结果表明,与传统的有源PFC相比,无桥有源PFC电路能够很好地提高系统的效率,降低开关器件损耗,抑制电流谐波,且输入电流能够很好地跟踪输入电压波形.     

基于DSP的大功率永磁直流电机调速系统设计

大功率永磁直流电机具有效率高、体积小等许多优点。设计了基于DSP的大功率永磁直流电机调速系统,系统功率电路采用IGBT模块作为开关器件,采用分时电路为主电路,即减小了输入电流的脉动,又减小了电机电流波动。为了减小系统的体积重量,系统没有输入电感,用IGBT储能电容抑制电压尖峰和输入电流纹波,给出了电容充放电电流计算公式,公式表明电容充放电电流最大值等于负载电流。利用PWM调制,实现了系统软启动、软关断和转速调节。实验表明,在最大转速时I,GBT电压尖峰小于输入电压的40%,输入电流波动小于额定值的25%。     

一种新型并联型零电流全桥DC/DC变换器

提出了一种新型的含并联辅助电路的零电流转换(ZCT)全桥DC/DC变换器拓扑结构。该变换器采用脉宽调制(PWM),通过在原边增加一个由电容和电感构成的并联有源辅助电路,在开关管状态发生变化时,控制辅助电路的谐振电流,实现了主开关管和辅助开关管的零电流开关(ZCS),也实现了输出整流二极管的软换流,使整流二极管承受的电压相对较低,即为输出电压,特别适合于开关器件为IGBT的高电压大功率场合,消除了IGBT拖尾电流引起的开关损耗,改善了电路性能。分析了变换器的工作原理及零电流开关的实现条件,给出了主电路拓扑结构和谐振网络相关参数设计。根据所选取的参数对主电路进行了仿真研究,结果验证了电路分析的正确性和可行性。     

IGBT小电流开通失效研究及结构改进

对绝缘栅双极型晶体管(IGBT)在小电流开关测试失效进行了分析研究,对IGBT栅极和集电极的电压电流波形监测发现,IGBT在小电流开通时电压电流波形存在严重的振荡问题,电压幅值超过器件最大额定值,导致器件失效。分析了IGBT芯片电容和栅极电阻对小电流开通振荡的影响,通过对IGBT芯片结构进行改进,将小电流振荡抑制在安全值范围内,解决了IGBT小电流开通失效问题,改进后的IGBT器件性能参数和应用测试温升接近国外竞品。     

零电压双LLC谐振软开关超高频感应加热电源变换器

提出了一种用于超高频感应加热电源的双LLC谐振槽路的零电压谐振开关变换器.这种新型的拓扑结构能够吸收电路中杂散分布电感和器件内部的寄生电容,开关器件工作于零电压软开关模式,解决了一般高频变换器中分布电感电容引起的电压电流振荡过冲高和开关损耗大的问题.另一方面,由于输入端引入了高频平波电感,使得变换器同时具有电压型和电流型逆变器的优点,两只开关的控制不需要死区时间的限制,因而更加适合于高频工作.本文分析了电路的工作原理,并给出了1MHz频率下电路工作的仿真与实验结果.     

Pathological representation of the two‐output CCII and ICCII family and application

The pathological mirror and nullor representation of the two‐output current conveyor family is given. New pathological mirror and nullor representations of the two‐output current conveyor family are given and compared with the corresponding nullator norator resistors' realizations. Simplified representations of the two‐output current conveyors based on using two single‐output current conveyors are given. Two examples are given, the first example demonstrates the importance of the pathological representation in the generation of a family of 16 oscillators from a two‐output current conveyor‐based current mode oscillator. A second example of a current mode low‐pass filter using two single‐output inverting current conveyors is considered. Its simplified modeling using a single balanced output inverting current conveyor is compared with the original current mode filter and the simulation results are given. Copyright © 2010 John Wiley & Sons, Ltd.     

Simulation of Controlled Sources Using Operational Amplifiers

By using feedback around an infinite-gain controlled source four finite-gain controlled sources may be simulated. Cascading two of these yields other types of controlled sources. New configurations are obtained by compensating imperfect controlled sources and also by using a negative resistance in the feedback loop. By making use of the singular elements (nullator and norator), some alternative configurations are derived, raising interesting possibilities for network synthesis techniques which employ controlled sources. Finally, replacing infinite-gain controlled sources by operational amplifiers yields practical circuits.     

Generation and classification of CCII and ICCII based negative impedance converter circuits using NAM expansion

A new simplified generation method of negative impedance converter circuits (NIC) is introduced. The generation method is based on nodal admittance matrix expansion starting from the input admittance of the NIC circuit terminated by a load rather than treating the NIC as a two‐port network element. The four pathological elements, namely nullator, norator, voltage mirror and current mirror, are used in the generation procedure. Two classes of the NIC pathological circuits are defined; each class includes two types. Eight pathological NIC circuits are generated for each class. Two alternative current conveyor and inverting current conveyor‐based realizations for each pathological circuit based on alternative pairing of the pathological elements are defined resulting in a total of 16 NIC circuit for each class and a total of 32 NIC circuits. A new NIC‐based circuits realizing floating negative impedances are also introduced. Copyright © 2010 John Wiley & Sons, Ltd.     

低电压大电流整流电源并联供电

介绍了低压大电流整流电源的特点和组成,为了提高整流效率,应采用双反星形整流电路,介绍了此电路的工作原理.与之匹配的整流变压器有两种型式:传统的双反星带平衡电抗器整流变压器和三相5柱整流变压器,并介绍了后者的工作原理.当晶闸管双反星形整流器配置了三相5柱整流变压器,在多台并联运行时直流输出电流会发生剧烈振荡,详细分析了振荡的原因和改进的措施.     

An experimental investigation of a reactor‐type current limiter by cancellation of a noninductive state with power semiconductors

This paper presents experimental results on a new type of current limiter using a model current limiter. This type of current limiter consists of a reactor with two coils reverse wound so as to maintain the noninductive state in the core. A parallel circuit with a power semiconductor switch and a resistor is connected to one of the two coils in series. Maintaining the noninductive condition by turning on the semiconductor switch during the normal loading state, theoretically there is no voltage drop across the limiter, that is, the impedance of the limiter remains at zero. The limiter has a current limiting impedance value during current limiting performance under short circuit conditions. The principle is that, when turning off the semiconductor switch, the resistor is inserted in the circuit, so that the noninductive condition is canceled. The effects of the turn ratio of the reactor winding and the characteristics of the inserted resistor with linear and nonlinear characteristics are experimentally studied. The normal current through a semiconductor is reduced by taking a high winding turn ratio of the coil connected to a semiconductor. On the other hand, the voltage across the semiconductor terminals during the current limiting period increases in proportion to the winding turn ratio of the coil. The current limiting impedance and energy absorption of nonlinear resistors during the current limiting period are numerically analyzed and compared, and a method to determine the optimum winding ratio is proposed. © 2000 Scripta Technica, Electr Eng Jpn, 132(2): 19–28, 2000     

Power losses in symmetrical conducting sections located in a transverse harmonic magnetic field

The application of a general method which connects the numerical finite element method of Bubnov-Galerkin with the method of separation of variables for the analysis of eddy current power losses in long symmetrical linear non-ferromagnetic sections located in a transverse harmonic magnetic field is presented. On the basis of the relationships obtained the numerical calculations were performed and plots of eddy current power losses were made for the selected symmetrical conducting sections.     

应用于谐振型限流器的双分裂铁心电抗器研究

为了降低串联谐振型限流器中流过晶闸管短路电流的幅值和上升率,提高电容器旁路电路的可靠性,提出一种双柱双分裂铁心电抗器,将晶闸管串接在双分裂电抗器的一个支路,然后再与补偿电容器并联。系统正常运行时,双分裂电抗器表现为大电感,流过的电流很小;在电网线路发生短路故障时,晶闸管导通,双分裂电抗器表现为小电感,快速转移流过补偿电容器的短路电流,谐振状态破坏从而实现限流功能。设计并制作了一台应用于400 V串联谐振型限流器的双柱双分裂铁心电抗器样机,基于三维棱边有限元法对电抗器磁场分布和电感参数进行了计算。电抗器以单支路小电流模式运行时,电感为192 m H;以双支路大电流运行模式时,电感为151μH。通过短路电流冲击测试发现,双分裂电抗器可实现电流快速转移且两支路电流均匀分配,电感测试值与仿真值吻合较好。为了降低晶闸管的冲击电流,提出一种在保持单支路运行电感恒定的前提下调整双支路运行电感的方法,仿真结果证明了该方法的有效性。     

±800kV干式平波电抗器的国产化制造

介绍了国内干式电抗器企业的技术发展及其技术开发上的重大突破,干式平波电抗器以其对地绝缘简单、无油化、功率倒送不会产生临界电介质应力、运行维护费用低、重量轻等特点广泛应用于电力系统中。提出了±800kV干式平波电抗器的开发应从电场分布、电流分布和波分布等方面进行设计的观点。实例说明国内电抗器生产企业有能力通过自主开发设计来满足特高压直流工程的要求。