Research And Design Of Analog Control System Based On Domestic FPGA

Analog control systems have been widely used in wastewater treatment,nuclear power generation,food,petrochemical,power,and other fields.In the field of industrial control,the state of the controlled object is often constantly changing,which will affect the state of the front-end main control unit.At this time,to eliminate deviations,corresponding adjustments need to be made to the system.These analog parameter adjustments all have a delay process,and a single variable open-loop control system is used,After the changes in the above parameters,it is difficult to achieve normal values and the process is long.However,the analog control system adopts a closed-loop coordinated control strategy that incorporates the controlled equipment into the overall system,which effectively solves the problems existing in the single variable open-loop control system.Based on this,this paper conducts research on analog control systems applicable to the industrial field and designs a domestic FPGA-based analog control system that can achieve continuous closed-loop control of relevant parameters of generators,switch valves,and other auxiliary equipment,so that the analog parameter values of the controlled object can change or maintain within a certain range according to the set goals.This article first introduces and compares the current analog signal control systems at home and abroad,and summarizes the advantages and disadvantages of traditional control systems.Combining the technical specifications and design requirements of modern control systems,adopting modular design ideas not only widens the signal output range but also has good scalability and portability.This system utilizes a domestic GOWIN FPGA processor for incremental PID algorithm control,and outputs analog signals through a domestic DAC and V/I conversion circuit to complete closed-loop control of the equipment.Finally,the analog control system is measured and analyzed in combination with the international general signal source evaluation method and the technical indicators set in the Technical Conditions for Distributed Control Systems in Fossil fuel power station(GB/T 36293-2018).The entire system mainly includes an FPGA control system,digital isolation,linear regulated power supply circuit,DAC conversion,V/I conversion circuit,wire break detection circuit,and ADC voltage sampling circuit.After completing the hardware construction and software programming debugging of the system,the technical indicators of the system were evaluated and measured according to the proposed evaluation method.The experimental data showed that the system can output a current signal in the range of 4m A to 20 m A,and can complete PID control of the equipment.The absolute error of the output analog control signal is less than 16 μA.Temperature change rate less than 1 μA/℃,the system can withstand changes in the resistance value of the controlled equipment from 0 to 800 Ω,and operates stably for a long time within a variable load range,with fast response speed and good universality.It has a wide application prospect in the field of precision control.