晶闸管投切电容器过零检测电路的改进  

Improvement of Zero Crossing Detection Circuit of Thyristor Switched Capacitor

作　　者：李勇[1] 程汉湘[1] 陈杏灿 

机构地区：[1]广东工业大学自动化学院,广东广州510006 [2]中国移动通信集团广东有限公司广州分公司,广东广州510090

出　　处：《广东电力》2017年第1期69-72,115,共5页Guangdong Electric Power

基　　金：广东省自然科学基金资助项目(S2011010004950)

摘　　要：传统的晶闸管投切电容器的过零检测电路采用MOC3083型光耦合器触发晶闸管,存在容易产生击穿、误触发和损坏等缺点。针对此缺点,重新设计过零检测电路和晶闸管驱动电路。利用光耦合器和三极管的特性捕捉过零点,由光耦合器导通时输出的低电平信号作为过零信号,并由脉冲变压器来驱动双向晶闸管;由过零检测电路与晶闸管驱动电路共同作用得到过零投切信号,以单片机控制的方式来实现晶闸管的可靠触发。在600 V电压下进行试验,并将改进后的电路与传统的MOC3083型过零驱动电路进行比较,结果表明改进后的电路能够准确地检测晶闸管两端的过零信号,并在过零点时投入电容器,且冲击涌流小,较MOC3083型过零驱动电路可靠性高。MOC3083 typed optical coupler triggered thyristor is used for zero crossing detection circuit of traditional thyristor switched capacitor （TSC）, which may cause defects of breakdown, spurious triggering and damages. Therefore, it is re- quired to redesign zero crossing detection circuit and driving circuit of the thyristor. The zero crossing point（ZCP） is caught by making use of characteristics of the optical coupler and the triode, and the output low level signal is taken as zero crossing signal when the optical coupler is in breakover state and the bidirectional thyristor is driven by pulse transformer. Under the combined action of zero crossing detection circuit and driving circuit of the thyristor, zero crossing switched signal is ob- tained and then by means of single chip microcomputer control, it is able to realize reliable triggering of the thyristor. Ex- periment was carried out under 600 V voltage and the improved circuits were compared with traditional MOC3083 typed zero crossing driving circuit. Results indicate that the improved circuits can correctly detect zero crossing signals at both ends of the thyristor, and input the capacitor at ZCP with small impact flow, which means higher reliability.

关 键 词：晶闸管投切电容器 过零检测电路 驱动电路 单片机 

分 类 号：TM714.3[电气工程—电力系统及自动化]