ارائه مبدلهاي سوئيچينگ نرم اصلاح ضريب توان بدون پل

چكيده انگليسي :

Soft Switching Bridgeless PFC Converters Mohammad Mahdavi Mazdeh mu mahdavi@gmail com 03 04 2009 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiHosein Farzanehfard hosein@cc iut ac irAbstract Recently the use of rectifiers connected to network has increased Since these rectifiers are nonlinear loads they inject unwanted frequencies into network system These harmonics create losses and overheating intransformers excessive current in the neutral conductor of three phase four wire systems distortion of theline voltage via the line impedance electrical resonances in the power system telephone interference errorsin metering equipment and reducing power factor Therefore different standards are established to reducethese undesirable effects So the use of PFC converters is compulsion Conventional PFC converters havehigher conduction Losses than rectifiers For reducing conduction losses the Power Factor correction blockmust be combined with DC DC regulator or rectifier that the resulting converters are called single stage PFCand bridgeless PFC respectively Since bridgeless PFC converters are usable in all electrical equipments thatneed to rectify AC voltage and the lowest conduction losses in all PFC converters in this thesis softswitching techniques are used to further increase the efficiency In literatures for reducing the switchinglosses the lossless snubbers Zero Voltage Transition ZVT and Zero Current Transition ZCT techniquesare applied to bridgeless PFC Three soft switching Bridgeless PFC converters are introduced in this thesis First proposed PFC converter prepares soft switching condition without any extra switch This converter hasfewer components than other converters that have not any extra switch This converter is controlled bychanging of switching frequency Therefore EMI of this converter is reduced by distribution of EMI noise infrequency domain A ZCT technique that has no extra stress on main switch is applied for second proposedPFC converter This converter has lowest extra elements in soft switching bridgeless PFC converters It canuse any control strategy that is used in conventional PFC converter by adding three extra elements to controlcircuit Therefore the conventional Pulse Width Modulation PWM control IC can be used Third proposebridgeless PFC uses a ZVT technique for soft switching of all semiconductor devices This technique haslowest conduction losses in auxiliary circuit because the number of elements that are in resonance path isreduced to two elements It can use any control strategy that is used in conventional PFC converter by addingthree extra elements to control circuit Therefore the conventional PWM control IC can be used Operation ofall converters is explained and the simulation results are given A prototype of each converter is constructedto verify the theoretical analyses The experimental results show soft switching of all semiconductor devices Keywords Power Factor Correction PFC Soft switching Boost converter Bridgeless PFC converter Zero CurrentTransition ZCT Zero Voltage Transition ZVT

مهدوي مزده، محمد

ارائه مبدلهاي سوئيچينگ نرم اصلاح ضريب توان بدون پل

PFC , مبدل بوست , مبدل اصلاح ضريب توان بدون پل ZVT-5ZCT-4