Research Of RTOS Based Versatile PID Controller

This paper mainly reaches the design and realization of a versatile digital PID controller.The digital PID algorithm is widely used in industry,and many controllers work based on this theory,with specific functions,there are many different applications with different performance requirements,and the controlled object differs such as voltage,current,or equivalent resistance,the purpose of this paper is to present the design of a versatile PID controller and its application,detailed information of both hardware and software is contained in the paper,it is applied in three-phase full bridge circuit and proved excellent performance,and there is a large space of further application.The hardware of the versatile PID controller uses the ARM7 core S3C44BOX as the CPU,I/O module contains 4*4 matrix keyboards and 640*480 LCD and UART,the signal is sampled by the internal 10 bits ADC module of the CPU,it is competent for common use,two feedback interfaces(voltage,current)are adopted.The PWM is used as the output function,0～5v control signal is obtained by low pass filter and it connected to the trigger module of the main circuit.The embedded real time operating kernel uC/OSⅡis adopted as the main part of the system software,the GUI software package is used to manage input and output,the incremental PID algorithm is selected for calculation.The uC/OSⅡmanages the running of each task,and uC/GUI is responsible for LCD display and keyboards scanning.The PC end software is designed using C#.The versatile PID controller is now capable of stable voltage limited current control, stable current limited voltage control and constant V/I control and each mode can be shifted between each other manually or automatically,RTC is adopted as system clock, tasks can start at specific time or shift mode,the PC end software can be used to monitor the state of the hardware system.In the last chapter of this paper the application of this system in three-phase full bridge circuit is presented with detailed debugging trouble shooting.