直流传感器回馈补偿系统的设计  

Design of Feed-back Compensation System of DC Sensor

作　　者：王晓蔚[1] 任士焱[1] 

机构地区：[1]华中科技大学电气与电子工程学院,武汉430074

出　　处：《高电压技术》2007年第7期63-66,共4页High Voltage Engineering

基　　金：国家自然科学基金(50277018)~~

摘　　要：在磁势自平衡回馈补偿式直流传感器中,一次被测电流磁势绝大部分已被电抗器直接由交流电源提供的电流自动平衡掉,剩余磁势由直流传感器的回馈补偿系统补偿。直流传感器的差值电流回馈补偿电路利用双向铁心磁放大器的基本原理,在电抗器铁心的空腔内设置零安匝检测铁心和线圈以检测该半周期内直流磁势平衡的安匝差,用于自动跟踪补偿,是一个具有反馈特性的闭环系统。差值补偿电流输出与磁势自平衡电流输出的和即为被测直流电流。为了分析控制系统的稳定性,用方块图来表示控制系统的组成。差值电流回馈补偿系统是一个典型的闭环系统。应用劳斯及古尔维茨稳定判据,通过特征方程的根与各项系数的关系来判别系统的特征根是否全部具有负实部,从而分析线性系统的稳定性。This paper has introduced the design of DC sensor＇s feed-back compensation system. The DC sensor is divided into 2 types of principle based on open loop and closed loop measurement theories. The sensor based on open loop theory has many advantages such as simple construction, small volume, and lightweight. The oscillation and heavy driving power doesn＇t exist. The sensor based on closed loop theory has many advantages such as high accuracy, good linearity, strong anti-interference and so on, but it also has disadvantages such as the stability problem brought by high open loop gains （generally greater than 1000）. Its circuit is complex and its high-power drive is difficult. The new type of DC sensing theory and method based on self-balance of magnetic potential and feedback compensation which combines the advantages of the open loop theory with advantages of the closed loop theory is developed. The DC sensor＇s feed-back compensation system is a representative closed-loop system which has a feedback characteristic. A differential current compensation circuit is composed by detecting cores C2 and C3, coils W50 and WDC, compensation coil W0, differential current measurement unit and amplifier A. The zero ampere-turns compensation of the detecting core is realized by this circuit. The system composed of the detecting and compensation coils and electronics module A is an automatic DC compensation system whose open loop gain is small. The compensation current of this system still has the characteristic of automatically tracking that is outstanding advantage of closed loop system. The sum of the secondary balance current /2, and the compensation current I2c multiplies by the proportion coefficient W2, then the primary measured direct current can be obtained. In order to analyze the stability of control system, the block diagram is constructed. Finally it can be judged that the DC sensogs feed-back compensation system is stable according to the Routh Criterion.

关 键 词：磁势自平衡 回馈补偿 PID控制 劳斯判据 传递函数 稳定性 

分 类 号：TM761[电气工程—电力系统及自动化]