Research On Dgitial Power Supply Minimum System Based On AVR Microcontroller

With the rapid development of power electronics, switching power supply has been widely used, the ever-changing high-tech products to a higher switching power supply requirements. The existing power source widely uses TL494, UC3875 and so on special-purpose power source chip to drive the switching valve,the chip itself is unprogrammable, poor to control,difficult to extend,difficult to upgrade and repair, while the power chip is difficult overcome by the temperature drift and aging caused by error, can not guarantee that the system always has the precision and reliability. But the digital control can solve these problems and also implement complex control strategy. The digital controller has higher reliabity and stability,and the design of digital controller is flexible.The digital controller can realize the intellgent power and reduce the design cycle of new products. Recent years, with digital control, digital control circuit structure of the development and market demand-driven, digital control power supply in the power field advantage will become increasingly evident.On this basis,we use simulation software platform for digital switch into the study.In this paper, Firstly,the digital control's characteristics,advantages and the current market situation were introduced,the challengs of the digital control facde in use was pointed out.An in-depth study on the digital contol technology of power supply was accomplished,such as the design method of digital controller,digital control strategy,digital control algorithm,and other main questions which existed in digital control system.Secondly,Based on the system performance analysis,we design the system plan, and then on the main circuit analysis, design parameters of the main circuit of the hardware, And using simulation software to the main circuit to verify design intention.Thirdly, we use the simulation methods to design digital controller and use software to analysis it.Digital PID algorithm plays an important role in digital control of the power supply. the installation method has generally collects the expansion critical proportion law, the expansion response curve law and so on, but these methods design's PID parameter is obtains through the experience, the precision is not high. Therefore, in this paper PID parameter setting is the use of time domain and frequency domain, this method is simple,direct and fast, moreover designs the parameter accuracy is high.