Research On The Digital Switching Power Supply

The development of microprocessor provides a new method for switching power supply. Digital controller has many advantages such as it is programmable, immune to component changes due to variations, easy-to-be monitored and so on. So the more and more attention has been paid. Digital Signal Control (DSC) which is the integration of the DSP and the MCU is the industry's development trend of digital power supply. This thesis focuses on the study, implementation and improvement of a DSC based switching mode power supply.This thesis firstly introduces the construction, characteristics and development trend of the digital power supply, studies on the key points which are faced by designer trying to optimize the digital control system's performance. Secondly the digital control application, which consists of a digital AC-DC PFC and digital phase-shift full bridge DC-DC converter, is developed. The Man-Machine interface is designed using Labview at last. The detail design process is depicted, including the hardware and software design and experimental results. Furthermore, considering the characteristic and the advantage of the digital control, an improved PFC strategy is studied, based on one-cycle interleaving control, which is a more simple arithmetic for PFC in comparison with the traditional average current control. Because of a small amount of calculation without multiplier, low-performance chip will meet the requirements using one-cycle control PFC arithmetic. The new type of PFC solution is analyzed in detail, and some simulation and experiment results are presented to verify proposal idea. The thesis finally studies a novel control technique-V~2 control (Voltage-Voltage Control) for DC-DC converter. The digital control law for each modulation method on buck converter is derived and simulation is performed to verify the V~2 control has better transient response for DC-DC stage.