Research On Novel Three-Phase Power Factor Correction Circuit

With the development and application of power electronics technology,a large number of power electronic devices are connected to the power grid,and the rectifier is widely used as a power conversion device for the power grid to supply DC loads.In view of the serious harmonic pollution caused by the current harmonics of the grid side of the traditional rectifier,two novel PFC(Power Facter Correction)circuit topologies are proposed.Through the synthesis of the grid side current space vector,the grid side current power factor correction and the DC side voltage drop are realized.The soft switching characteristics of the novel PFC circuit reduce system switching losses and improve system efficiency.This paper focuses on the buck-type three-phase PFC circuit topology suitable for high-power applications:Firstly,the development and research status of high-power buck-type three-phase PFC circuit are analyzed.Among the influence of traditional uncontrolled or semi-controlled rectifier on the power grid,introduces several typical voltage-type PWM rectifiers Topology with PFC function and its characteristics;for the application of high current and low voltage output,introduce several typical buck-type three-phase PFC circuit topologies and their characteristics.Secondly,four typical PFC circuit topologies are selected,and their working principle and typical working mode are analyzed respectively.Two kinds of commonly used rectifier mathematical model are introduced as the object of three-phase bridge rectifier: First,Mathematical model based on three-phase stationary coordinate system;Second,the mathematical model based on the d/q rotating coordinate system.Thirdly,two new PFC circuit topologies are studied: a new buck-boost three-phase PFC circuit topology;a new buck-type three-phase PFC circuit topology.The working principle and working modes are introduced respectively.The principle of PFC is explained by the establishment of current space vector.The control strategy of new topology is introduced,and the influence of in-phase carrier and interleaved carrier modulation on current ripple is compared.Simplify the system circuit,establish the equivalent working circuit,derive the small signal model by the state space averaging method,and then obtain the system transfer function;obtain the system Bode diagram from the transfer function,and combine the final value theorem to show that the system is stable;The simulation software Matlab/Simulink verifies the characteristics of thecircuit topology.Fourthly,taking the buck-type three-phase PFC circuit as an example,designing and selecting the hardware parameters of the main circuit of the system,introducing the design of the auxiliary power supply and peripheral circuits;respectively,constructing a buck-boost three-phase PFC circuit experimental prototype and a buck-type three-phase PFC circuit experimental prototype,through the steady-state and dynamic system voltage and current waveforms,illustrate the characteristics of the new topology in actual operation.