Design And Thermal Analysis Of Nuclear Power Emergency Diesel Generator Electronic Control System

With the vigorous development of China’s nuclear power industry,the safety of nuclear power plants cannot be ignored.Emergency diesel generator as 1E class backup power for nuclear power plant is that the key equipment for the safe operation of nuclear power plants.It must have a fast start response to provide stable and reliable power for nuclear power equipment in the event of a sudden power outage in a nuclear power plant.As the core of the stable operation of the diesel engine,the Electronic Control System needs to have strong stability.Aiming at the working characteristics and control requirements of nuclear power emergency diesel engines,this paper designs and develops a nuclear power diesel engine control system with industrial application capability,and analyzes its stability under different environmental temperatures.According to the functional requirements of the nuclear power diesel ECU.Analyzes the working principle,hardware requirements,selection of control algorithms and the overall program flow of control system speed adjustment.Finally,the 32-bit microprocessor MPC5644 A from the Power PC series of Freescale was selected as the system control chip,and designed the hardware circuit of the diesel engine’s electronic speed control system.It mainly includes MCU minimum control system circuit,power management circuit,input signal conditioning circuit,output drive circuit and communication circuit.According to the designed ECU circuit board,the thermodynamic simulation analysis software Icepak is used to establish the component-level and board-level thermal design models for the ECU.Through the simplification of the model,the division of the grid and the determination of the boundary conditions,the temperature field distribution of the ECU circuit board and components is obtained.And then,studied the adaptability and operating temperature of the system at different ambient temperatures.The results show that the electrical control system of the nuclear emergency diesel engine designed in this paper has sufficient temperature stability to cope with the change of the working environment temperature of the nuclear power plant.Finally,According to the requirements of diesel engine speed control and the on-chip resources of MPC5644 A,designed software for the control system.It mainly includes the design of watchdog reset program,switch driver and analog driver,as well as the design of system timing interrupt software,PWM control signal output program and CAN bus communication program.Finally,aiming at the important speed control functions of the system,analyzes the specific design process of the PID control algorithm.Software analysis and design of the calculation process of target speed and speed drop.The functional requirements of the ECU module are basically realized.