Research On Hardware And Software Of Double-loop Cascade Speed Control System

With the developing of the modern cascade speed-control system, it has a widely used. Relative to the frequency control system, the modern cascade speed-control system cover a small area, has a low maintenance, low voltage converters and small power converter. However, most modern cascade speed-control systems are based on open-loop control system. It obviously does not meet the requirements for those speed control system, which require high control accuracy.According to the principle of the modern cascade control system, Details modeling and determine the system block diagram of modern double-loop cascade control system. According to the engineering design method, we should design the inner current loop first and then design the outer speed loop. The current loop is designed as a typical typeâ… system and the speed loop is designed as a typical typeâ…¡system.At last correct the parameters of the speed and current controller.According to the design requirements of digital control system, complete a digital dual-loop control system software and hardware implementation by using the ATMEL ATmega128 microcontroller. The hardware of digital dual-loop control system include ADC sampling circuits, PWM control signal output circuit, Set and display duty cycle circuit. According to the design features of each part of the circuit, software design includes ADC sampling procedures program, PWM control signal output program, digital PI controller program. Then test software design by using AVR experimental development board. Experiments show that the functional module can work properly. To achieve Dual closed-loop digital control through the main function calls the function module.