| With the development of power electronic technology,the types of electronic devices are becoming more and more abundant,and the relationship between people’s work,life and electronic devices is getting closer and closer.The power supply should not only provide source support for the stable operation of electronic equipment,but also meet the special requirements of some products,such as the requirement that the power module has good dynamic response performance,which is an indispensable part of all kinds of electronic equipment.Compared with continuous current mode(CCM)and critical conduction mode(CRM)Boost PFC converters,the discontinuous current mode(DCM)Boost PFC converters have the advantages of constant operating frequency,zero current conduction(ZCS),no reverse recovery process of diode and simple control loop.This control method only needs to know the power ratio before and after the load jump.When the load jump is detected,the output voltage error signal is multiplied by a coefficient for duty cycle adjustment,so as to ensure that the output voltage error signal does not undergo significant adjustment.This paper presents a load calculation method based on the maximum/minimum point of output voltage.The maximum/minimum point of output voltage when the load jumps at different phase angles is analyzed in detail,including jumping from heavy load to light load,jumping from light load to heavy load.The characteristics of output voltage extreme value are summarized,and the load conversion multiple calculation programs are designed.This method eliminates the power loss caused by the sampling resistor without the need of the output current sensor,and the advantages of the proposed load estimation method are more prominent in the case of low voltage and large current load.Finally,a 120 W prototype is made and the digital control scheme is given.The experimental results prove the effectiveness of the proposed control scheme. |
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