A Research Of On-line-Tuning Nonlinear Controller For Digital DC-DC Converters

Digital DC-DC converter adopts digital control method,which changes the weakness of customization of analog scheme.It has the advantages of natural flexibility,embedded programming,easy design and transplantation,and real-time monitoring and management.It can be widely used in high-end electronic applications with intelligent configuration power supply.Firstly,the transfer functions of the digital DC-DC converter system and its parts(power stage,ADC,DPWM)and the modeling of MATLAB-Simulink are analyzed,which lays a good foundation for the loop verification of the digital control parts(DPWM,DPID).DPWM adopts a hybrid basic structure with self-calibration mode,adds the function of precision selection,optimizes the delay chain,and designs a new decoding method.The final DPWM can eliminate the influence of process deviation,realize flexible adjustable switching frequency of 500 kHz,1 MHz and 2 MHz,and achieve high precision and high linearity output of 143 ps.VCS simulation of digital hybrid structure with fuzzy delay is realized by means of SDF backmarking.DPID uses PID control rules to get discrete transfer letters,and then decomposes the transfer letters,establishes the MATLAB-Simulink model,and completes the hardware design.The parameters of P,I,D,N and P2 in DPID are tuned according to the phase margin,and the optimal configuration position is selected to complete the algorithm design of parameter tuning.The Verilog code is designed according to the model,which corresponds to the simulation result of MATLAB under VCS simulation.Based on the design of DPID,a two-dimensional fuzzy controller composed of 25 rules is designed to realize non-linear control.The stability time of load step is 25 mu s and the overshoot is reduced to(25-30)mV,which greatly improves the problem of poor dynamic response caused by digital circuits.At the same time,the gradual elimination recursive least squares method is added to solve the device aging problem,and the prediction function is verified by language verification,power level model verification and loop model verification,respectively.The designed Verilog code generates gate-level network tables and then carries out VCS simulation with SDF counter-standard.Through IC layout and routing,the timing is corrected,GDS is generated,and Cadence is imported to complete physical implementation and layout verification.Based on the high-end electronic application with adjustable switching frequency and wide range,this paper completes the digital control part,including 12-bit high-precision hybrid DPWM and 10-bit input and 12-bit output non-linear controller DPID which can be tuned online.