Research On Multi-frequency Control Technology Based On Frequency Synthesis And Application In Converter

With the continuous development of new energy technology,electric vehicle industry and portable devices,a large number of integrated circuit electronic devices and new energy devices nowadays have higher requirements on their power supply and power electronic conversion equipment in terms of stability,steady-state operation accuracy and dynamic response speed.The traditional Pulse Width Modulation（PWM）has been widely studied by scholars and put into practical application on a large scale,and the technology is very mature,but there are inherent defects such as low efficiency of light load and slow dynamic response speed.Therefore,the multi-frequency control technique based on frequency synthesis is proposed and its application in switching converters to improve the performance of DC-DC switching converters is explored and studied in this paper to meet the needs of the industry.Firstly,this paper studies the control principle and implementation of the Bi-Frequency（BF）pulse sequence control technique with fixed on-time,and analyzes its control pulse combination law,steady-state characteristics,and transient response characteristics.The problems of compromise between output power and output voltag e ripple and loss of output voltage regulation under light load or no-load conditions are pointed out through the research and analysis of the dual-frequency control technique applied to the inductor current discontinuous conduction mode（DCM）switching converter.To address these problems,this paper proposes a multi-frequency control technique based on frequency synthesis and investigates it in a DCM Buck converter.A multi-frequency control technique based on frequency synthesis is proposed in this paper.By combining a blanking pulse signal with the original dual-frequency pulse signal on the basis of the dual-frequency control technique,it can extend the regulation range of the converter under light load or no-load conditions.And it effectively improve the output power range of the converter,reduce the output voltage ripple,and solve the problems of the traditional dual-frequency control technique in DCM switch.This paper presents a detailed analysis of the frequency range of the final value method.This paper analyzes in detail the working principle and implementation of the final value method frequency synthesis multi-frequency control technique,and analyzes its steady-state characteristics such as output voltage range and output power range.The results show that the proposed method effectively improves the problems of the dual-frequency control technique in DCM switching converters.The frequency synthesis multi-frequency control technique with variable control target is proposed in this paper.It has higher output voltage accuracy than the final value method frequency synthesis multi-frequency control technique,and retains the advantages of wide output power range,suitable for light load or no load,and low output voltage ripple.The working principle of frequency synthesis multi-frequency control technique with variable control targets is analysied in detail in this paper.By analyzing in detail,the change trend of key parameters of DCM Buck converter,such as the change amount and change rate of output voltage and inductor current within one switching cycle,and realizes the control of blanking pulse duration to achieve different control targets of the converter.The duration of the blanking pulse is calculated,and the control of the duration of the blanking pulse is realized to achieve the regulation of different control targets of the converter.Finally,the corresponding experimental platform of Buck converter is built,and the control technology is implemented by DSP-based digital control method.A large number of simulations and experiments have been conducted for the theoretical analysis,and relevant experimental results and data are given to verify the correctness of the theoretical analysis.