Research Of Control Method And Design Of Single-cell Electrical Injection Digital Power Based On STM32

With the development and application of computer and embedded microprocessor technology, digital control began to enter the control field of switching power supply Compared with analog control technology, digital control technology has many advantages, for example, digital control not only can realize more complex control algorithms, but also can realize the real-time monitoring of the power system working-status, set power parameters flexibly and diagnose of the power failure on-line. The embedded microprocessor has some advantages, such as, abundant external devices resources, higher processing speed and so on, which makes it widely used in the design and under development of digital power applied in single-cell electrical injection. Digital control technology can short the research and design cycle of digital power control circuit, so we can modify the program simply to realize the improvements and upgrades of the control algorithm. Therefore, the digital design of single-cell electrical injection digital power has become a hot topic in the practical design.This article is supported by the National Natural Science Foundation project "The Development of a Multi-analysis mode & Multi-function micro-fluid IC chip single cell analyzer (approval number:21327007)".For the index requirements and characteristics of output the smaller voltage ripple coefficient, the wider output voltage range and the flexible adjustment on single-cell electrical injection digital power, This article develops a special single-cell electrical injection digital power based on the STM32 microprocessor to improve the performance index. The digital power supply developed in this article has the following characteristics:Firstly, low cost and simple structure; Secondly, the use of the positive-negative symmetrical fold voltage rectifier circuit can effectively restrain the output voltage ripple coefficient; Thirdly, realize a wider range of voltage (160V-630V) and adjustable output; Finally, using the STM32 embedded microprocessor to realize the digital control.Key content and achievements made by this article is mainly reflected in the following aspects:To begin with, The basic working principle of switching power supply and the half-bridge topology of main circuit is carried out a detailed analysis; In addition, the dual-loop PID control strategy for current and voltage are also studied on the basis of the exploration of regulation control on switching power supply for is conducted.Secondly, the single-cell electrical injection digital power system control strategy is studied, and the complex control algorithm combined BP neural network and conventional PID is focused. The conventional PID control theory, analog PID control system and digital PID control system are introduced. The tuning process and rules of PID parameters are also given. Combining with conventional PID control algorithm, the complex control algorithm combined BP neural network and conventional PID is studied to achieve PID self-tuning parameters by overcoming the issues of complex PID parameter adjustment; The simulation comparison with traditional PID control is conducted, and the simulation results show that the algorithm proposed in this study can effectively improve the system overshoot, improve system dynamic and static performance advantages.Thirdly, the hardware design process of single-cell electrical injection digital power prototype, each module hardware circuit diagram and key module parameters of high-frequency transformers are provided.Fourthly, the software design of single-cell electrical injection digital power prototype is completed and developed. The software implementation process of the two-way complementary symmetrical PWM control signal, PID regulation control and isolation sampling of output voltage are described in detail.Finally, after theoretical analysis in-depth and simulation of control strategy, the single-cell electrical injection digital power prototype system based on STM32 is designed. And then its performance has been tested. After the analysis of the input voltage mutation waveform and the output voltage waveform in the case of no-load and load, the reliability and stability that when resisting outside interference case of single-cell electrical injection digital power system in the paper are verified.