Buck型DC-DC变换器中数字预测模糊PID控制器的设计与实现

Design and implement of digital fuzzy PID controller with prediction algorithm for Buck DC-DC converter

为了提高数字DC-DC变换器的瞬态响应性能,设计了一种基于数字预测控制方法的模糊PID控制器.该控制器根据Buck型DC-DC变换器的电路结构,准确预测单个开关周期或多个开关周期后的负载电压和电感电流,以克服环路时延对系统瞬态响应的影响;同时,在基本PID控制基础上引入模糊控制,实时在线调整PID控制参数,以克服变换器的非线性特性对瞬态能力的影响.所设计数字控制器经FPGA验证,结果表明,与基本PID控制相比,所设计数字预测模糊PID控制器能有效提高变换器的瞬态响应能力,变换器的瞬态响应时间缩短1/3,电压超调量小于5%.

To improve the transient response of digital DC-DC converter,a digital fuzzy proportional-integral-derivative （PID）controller with a prediction algorithm is proposed.In the digital controller,the output voltage and inductance current after one cycle or multiple cycles are predicted accurately based on the circuit structure of Buck DC-DC converter,which overcomes the influence of loop time delay on the transient response.Meanwhile,fuzzy control is introduced in the basic PID control to overcome the influence of the nonlinear characteristics of converter on the transient response through the real-time online regulation of PID control parameters.The proposed digital controller is implemented by the field programmable gate array （FPGA ）.The results of verification show that the proposed controller can effectively improve the transient response of converter compared with basic PID control.The transient response time of converter can decrease by one third and the voltage overshoot is less than 5%.