Research On Topology And Control Method Of Single-stage Buck And Boost Rectifier

At present,data centers,new energy electric vehicles,consumer electronics and other fields are developing rapidly.With the proposal of the "double carbon" goal,AC-DC rectifiers are developing towards high efficiency and miniaturization in order to fully improve energy utilization.The traditional rectifier generally adopts a two-stage structure,including a front-stage power factor correction circuit(Power Factor Correction,PFC)and a post-stage DC conversion circuit.In the low-voltage application of a single-phase twostage rectifier,the input voltage undergoes a two-stage energy conversion of boosting first and then stepping down,resulting in additional switching loss.In order to improve the efficiency of the circuit and reduce the cost,aiming at the high efficiency demand of the rectifier converter,this paper constructs a Buck-Boost rectifier converter topology based on the single-stage conversion of energy.The single-stage Buck-Boost rectifier topology proposed in this paper is an efficient Buck-Boost dual-mode switching rectifier converter obtained by combining the Boost PFC converter topology,adding a bidirectional switching structure and multiplexing the rectifier bridge,and optimizing the power device and bridge arm structure.When the input voltage is higher or lower than the output voltage,the converter operates in Buck or Boost mode.On this basis,this paper analyzes the working principle of the circuit during singlemode and dual-mode switching in detail.Under the same circuit parameters,the current operating characteristics of Buck and Boost modes are analyzed,and the PFC theoretical calculation is carried out.For the single-stage Buck-Boost rectifier converter,the small signal models in different modes are established,and the compensation link of the digital control loop suitable for two modes is adopted to obtain the voltage and current double closed-loop control strategy suitable for the circuit.At the same time,in order to realize the smooth switching of two modes,the mode switching control strategies of dual modulated wavesingle carrier and single modulated wave-dual carrier are adopted,which can suppress the input current waveform distortion caused by the high-frequency switching of Buck and Boost switches.In addition,the losses of energy storage elements and semiconductor power devices of single-stage Buck-Boost rectifier converter are theoretically analyzed and calculated.Using the simulation software to build a model to verify the circuit,the circuit can achieve a wide range of stable voltage output and obtain a better input current waveform.The simulation results verify the accuracy of the theoretical analysis,parameter design and control strategy of the converter.Finally,an experimental prototype of 1.1k W singlestage step-up and step-down rectifier is built.The experiments further verify the feasibility and effectiveness of the proposed topology and its control strategy.