طراحي و پياده سازي مبدل هاي اصلاح ضريب توان بدون پل مبتني بر باك‐بوست

چكيده انگليسي :

Design And Implementation Of Bridgeless Power Factor Correction Converters Based On Buck Boost Mohammad Mahmoodsaleh m mahmoodsaleh@ec iut ac ir August 2020 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Ehsan Adib e adib@cc iut ac ir advisor Dr Hossein Farzanehfard hosein@cc iut ac ir Abstract Today with the rapid growth of electronic equipment Demand for DC power supplies is growing Rectifiers are widely used in application industries to convert main AC voltage to DC voltage Sincerectifiers include diodes and large capacitor that are nonlinear loads Therefore electronic equipmentinjects harmonics into the power system which results in increased Total Harmonic Distortion THD Rules and standards such as the International Electrotechnical Commission IEC 61000 3 2 limitthe harmonics produced by these devices At present Power Factor Correction PFC circuits witha wide range of industrial applications is an effective method to meet the aforementioned standards Single phase and three phase ac dc power converters can be implemented with PFC for low powerand high power applications respectively Among the many options the Boost converter is widelyused as a power factor correction This converter has several advantages such as simple control andhigh PF However its output voltage should be higher than the peak voltage of the input voltage Therefore the researchers introduced the Buck and Buck Boost converters as PFC for applicationsthat demand low output voltage for electronic equipment However for buck types PFC convert ers when the output voltage is higher than the input voltage the dead angle emerges in the inputcurrent which leads to low PF and high current distortion In this thesis two bridgeless PFCs withinput single phase and a buck boost PFCs with input three phase are introduced at first of the thesis the definition of power factor and its mathematical relation are presented and then advantages anddisadvantages of basic switching converters are mentioned To increase the efficiency bridgelessPFCs are reviewed In bridgeless PFCs rectifier is combined with the PFCs converter to create anew converter Because the number of semiconductor devices are reduced in bridgeless PFCs theconduction losses are reduced and efficiency is increased In the first proposed PFC converter op erates at Discontinuous capacitor voltage mode DCVM and discontinuous inductor current mode DICM hence inherent PFC is achieved with a simple pulse width modulation PWM control Also the switch of the proposed converter can operate with Zero Current Switching ZCS turn on andZero Voltage Switching ZVS turn off without applying any extra element The second proposedPFC using lossless snubber converter can operates under ZVS condition Laboratory prototype ofthe proposed bridgeless PFCs are designed and implemented to verify validity of theoretical analy sis Furthermore the input current of the proposed converters are dead angle free For design highpower converters three phase converters to be considered as a better option than single phase con verters Therefore in the third proposed PFC converter with three phase input is simulated The thirdproposed PFC structure improves the power density by employing two switches Due to reductionof the number of semiconductors in the power flow path and providing soft switching condition forsemiconductors efficiency of proposed bridgeless PFCs are high and above 92 Key Words Power Factor Correction PFC Soft Switching dead angle Total Harmonic Distortion THD

محمودصالح،‌ محمد

طراحي و پياده سازي مبدل هاي اصلاح ضريب توان بدون پل مبتني بر باك‐بوست

اصلاح ضريب ‌توان , كليدزني نرم , زاويه مرده , مبدل هاي اصلاح ضريب توان بدون پل