Research And Design Of Digital Switching Power Supply Controlled By V~2C

Digital switching power supply overcomes the disadvantages of the simulator of compensator in analog switching power supply,such as being susceptible to external interference and unable to track the status,etc.,which has become a trend of the development of switching power supply.Switching power supply control has always been a research hotspot in power supply design.At present,in addition to the traditional control methods such as single-loop voltage control,double-loop peak current control,V~2 control,and so on,there are also fuzzy control and sliding mode variable structure.Compared with the new control method based on digital control,the new control method is only more accurate and flexible than the control method.Its application in power supply has not broken through the limitation of the double feedback loop,and the improvement in dynamic characteristics is limited.The three-loop V~2C control can break through the limitation of the dual feedback loop and has better dynamic performance.Since it was proposed in 2005,the research is mostly software simulation,less hardware verification and application,and all are analog control.Research on its digital control.Based on this,this paper studies and designs a digital switching power supply controlled by V~2C,which aims to make the digital power supply have better anti-interference dynamic characteristics after being subjected to load changes.This article uses an indirect design method based on continuous systems.A small-signal model was established for the Buck converters of voltage control,peak current control,V~2 control,and V~2C control,respectively,and Matlab was used for simulation comparison.The results show that V~2C control has better anti-interference dynamic characteristics.The effects of time quantization and amplitude quantization are analyzed.A digital V~2C controlled Buck converter loop small-signal model is established.For the model without considering the influence of the zero-order retainer,several continuous system designs are compared Discrete equivalent method,select w transform design method to improve.By comparing the discrete PID control and the zero-pole compensation method,it is considered that the discrete PID control cannot accurately control and compensate the digital V~2C controlled Buck converter when considering the equivalent series resistance of the capacitor,and the zero-pole compensation method is used to obtain the digital compensation After the device,design the hardware and software system.The hardware design includes the minimum system design of the main control chip,the PWM MOS tube drive circuit design,the auxiliary power supply design,the signal conditioning circuit design,and the OLED circuit design.The software system design includes the control flow of the entire system and some important code configuration instructions,the programming of the z-domain discrete compensator,etc.Finally,after ensuring that the parameters of the Buck open-loop circuit are properly selected,the Buck circuit under several control methods is simulated.The data shows that the V~2C control takes into account good anti-interference with small overshoot and short recovery time after a sudden load change Characteristic.Test the digital power hardware,the output voltage ripple is 10.955mV,and the rising time is 120μs.The overshoot of output voltage 5A to 1A was 14m V,the overshoot of 1 Ato 5A was 12mV,and the load mutation recovery time was 104μs.The power efficiency of la-5a with load is above 85%,and the efficiency is the highest at 3 A,which is 91.34%.The actual measurement results verify the simulation results of the software and reach the expected target of the design.