基于现场总线的高隔离度可调直流电源嵌入式控制器设计

Design of Adjustable High Isolation DC Power Embedded Controller Based on Fieldbus

模块级联是用于绝缘实验所需的高性能对称双极型矩形波脉冲电源的一种方法,为实现级联,需要有能够协调工作的高隔离度直流电源;设计出嵌入到各电源的板级嵌入式控制器BEC(Board-level Embedded Controller),使各BEC作为从节点利用RS485接口和ModBus协议与嵌入式主控制器EHC(Embedded Host Controller)构成一个主从式现场总线网络,并在主节点EHC的控制下协调工作;利用BEC内的STM32F103C8处理器产生隔离DC-DC桥的互补PWM控制信号和高隔离输出电压,并进行电流和输出电压的隔离检测;由基于电流切换的变参数增量式数字PI算法来确定脉冲宽度值,产生Buck调压电路的闭环PWM控制信号,实现输出电压的调压和稳压控制;实验结果表明该嵌入式控制器能够满足级联式对称双极型矩形波脉冲电源对高隔离度可调直流电源的需要。

The multi-module cascade is a method used for insulation test which need a pulse power supply of high-performance.Symmetrical,and bipolar.In order to cascade,it needs a high isolation DC power which can coordinated control.Designing the BEC（Boardlevel Embedded Controller） that which have embed to each power.As slave nodes,each BEC should utilize the RS485 connection and Modbus protocol with EHC（Embedded host controller） to constitute a master-slave fieldbus network,and working under the control of master node.Utilizing the BEC s STM32F103C8 processor to generate a complementary PWM controller signs which can isolate DC-DC bridge,and check the electric current,output voltage under isolation.Through the variable parameters incremental digital PI algorithm which based on the current switch to determine the value of pulse width to generate the closed loop PWM control signal of Buck regulating circuit,realizing voltage regulation and stabilization of output voltage.Experimental results show that the embedded controller can satisfy the cascading symmetrical bipolar rectangular wave pulse power supply for high isolation adjustable DC power supply needs.