Real-Time Computation Method With Dual Sampling Modes For Digital Controlled Buck Converter

With the development of the digital chips,digital control has been widely used in the control of power electronic converters.Compared with analog control,digital control can simplify the hardware control circuit and improve the reliability and anti-interference ability of the control circuit.However,digital control suffers from the problem of control delay,and the dynamic performance of the converters is deteriorated.Therefore,it is necessary to reduce the control delay.The digital delay includes the computation delay and the pulse-width modulation(PWM)delay.In the digital control system,the feedback signals are sampled in the current period,and PWM signals are loaded in the next period,thus one period of computation delay arises.When the symmetrical double-edge modulation is adopted,the digital PWM modulator will cause half period of PWM delay.In order to reduce the digital control delay,this thesis proposes a real-time computation method with dual sampling modes to remove the computation delay.For single buck converter,the real-time computation method with peak-valley dual sampling modes is proposed,which eliminates the computation delay completely and improves the dynamic performance.For the interleaved buck converters,the duty cycle prediction is further proposed to incorporate into the real-time computation method with dual sampling modes.By optimizing the sampling method,the resource occupied by sampling and calculation can be reduced,and thus the computation delay can be completely eliminated.Finally,a prototype of 2-k W interleaved buck converter is fabricated and tested in the lab,and the parameters design for the main circuit and control circuits is presented.The experimental results are provided,and it is verified that the proposed real-time computation method with dual sampling modes can greatly improve the dynamic performance of the digital controlled buck converter and interleaved buck converters.