Fuzzy PI double-loop control method based on stratification thoughts

Abstract

The invention provides a novel fuzzy PI double-loop control method based on stratification thoughts and a software and hardware scheme which is implemented by the method through a TMS320F2812DSP. According to the control method, a fuzzy control method is combined with a traditional linear PI voltage/current double-loop control method to form a closed-loop system according to the fuzzy control theory, and a boost convertor with given parameters serves as an embodiment for simulation verification. The simulation result shows that the dynamic performance and the static performance of the system can be greatly improved through the control method, protection can be achieved to the maximum degree, and the control design that the speed is as high as possible but does not exceed a protection limiting value is achieved. Besides overcurrent protection, special input inrush current limitation is further set, so that startup surge is retrained to the maximum extent, and power diodes for the startup surge are saved. The complexity and computation of the control algorithm with regard to stratification of input variables are decreased, and therefore the fuzzy PI double-loop control method provides possible thinking for flexibly achieving more additional control functions.

Description

technical field [0001] The invention relates to a DC-DC step-up circuit in the field of switching power supplies. Background technique [0002] The DC-DC converter is a time-varying nonlinear system. Due to the existence of various parasitic parameters and losses, it is difficult to establish an accurate model of its operation. The traditional linear PI control method is the most used in engineering. Although the design method of the single voltage loop control is simple and mature, its dynamic characteristics are slow, and it has been rarely used; the voltage and current double loop PI control has better dynamic and steady-state characteristics. , but because the controller is designed on the basis of assuming that the converter is a linear system, it is still difficult to meet the requirements in occasions with high performance requirements. So in recent years, researchers have gradually introduced control methods based on nonlinear systems to control power converters, an...

AI Technical Summary

Problems solved by technology

At present, there are two forms of combining fuzzy control and PI control: (1) voltage fuzzy PI control, which only uses the output voltage as the input control quantity, has better dynamic characteristics than single voltage loop PI control, but the response is still not good enough; (2) Fuzzy PI double-loop control, the combination of fuzzy control and current inner loop, the disadvantage is that the dynamics of the system are complex, it is difficult to analyze small signals, and it makes it difficult to design the voltage outer loop

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