带电压反馈智能接触器的热分析模型

Thermal Analysis of Contactors with Voltage Feedback System

针对智能与普通交流接触器热分析问题的异同点,建立了同时考虑主回路和磁系统发热的智能接触器热分析模型.该模型根据智能接触器的线圈控制回路在脉宽调制下交替导通-关断的特点,利用磁路法建立了线圈控制回路导通与关断时磁系统的特性微分方程组,并通过求解该微分方程组建立其磁系统的热源模型.同时,结合两种接触器的共同特点将普通交流接触器的热分析方法扩展到了智能接触器.利用该热分析模型对一采用优化线圈及铁芯参数的智能接触器在稳态工作下的温升进行了热分析,并进行了实验验证.分析结果表明,与普通交流接触器相比,智能交流接触器在更小的线圈及铁芯参数下,仍可有效降低磁系统的发热温升,且稳态工作下的温升满足国家标准要求.

Based on the similarities and differences of thermal analysis issues between the intelligent and general AC contactors,a thermal analysis model considering influences of both main conductor loop and electromagnetic system is constructed for the intelligent contactor.According to the alternating turn-on and turn-off characteristics of the coil circuit controlled by the pulsewidth modulation,the model constructs a set of differential equations with magnetic circuit meth-od to describe characteristics of the electromagnetic system and its thermal source model by subsequently solution to these equations.Linking with the features common of the two kinds of contactors,the extension of the thermal analysis method of general contactor to intelligent contactor is demonstrated as well.With the proposed thermal analysis model,the steady-state temperature rise of an actual intelligent contactor by an optimized coil and core parameter is evaluated and compared with the measurement.The analysis results show that the temperature rise of the miniaturized electromagnetic system of the intelligent AC contactor can be decreased effectively compared with the general AC contactor to meet the requirements of national standards.