Slide 1AgendaCentering Auxiliary Output Voltages on Multiple-Output ConvertersCentering Auxiliary Output Voltages on Multiple-Output ConvertersSlide 5Slide 6Slide 7Auxiliary Supply SystemsSlide 9Auxiliary Supply SystemsSlide 11Slide 12Parallel Operation of Voltage-Stabilized Power SuppliesSlide 14Slide 15Slide 16Slide 17ConclusionEE 136 Final PresentationProfessor Dr. ZhouPresented by:Cynthia DavidAgendaAgenda Part 1, Chapter 22Centering of Auxiliary Output Voltages on Multiple-Output Converters.Part 1, Chapter 23 Auxiliary Supply Systems Part 1, Chapter 24 Operation of Voltage-Stabilized Power SuppliesCentering Auxiliary Output Voltages Centering Auxiliary Output Voltages on Multiple-Output Converterson Multiple-Output ConvertersProblemObtaining an absolute output voltage value.Solution Saturable reactors – small toroids Used to control voltage and current control. Provides pulse width / timing techniquesCentering Auxiliary Output Voltages Centering Auxiliary Output Voltages on Multiple-Output Converterson Multiple-Output Converters  Saturable ReactorsSaturable Reactors with a forward converter .with a forward converter .Vout = Vs × ton / ( ton + toff ) from Chapter Vout = Vs × ton / ( ton + toff ) from Chapter 21 Part 121 Part 1 ExampleExampleGiven Vout = +12, -12, +5 Desire: 11.5 turns use 12 Higher Output Voltage is given ie. 12.7 ton = 15 µs toff = 18 µsCentering Auxiliary Output Voltages Centering Auxiliary Output Voltages on Multiple-Output Converterson Multiple-Output Converters Saturable ReactorsSaturable Reactorstd = ton – required V × ton / (actual Vout ) = 15 - (12*15) / (12.7) = .827 µs td is delay time, ton is on cycle,  Vs = Vout ( ton + toff) / ton = 27.9 V . td = Np × ∆B × Ae / (Vs) Np is the primary turns, ∆B difference in remanance flux from flux density saturation. Ae is the effective area of the core. Given ∆B = .4 Ae = Vs × td / ( Np × ∆B ) assume Np = 1.Centering Auxiliary Output Voltages Centering Auxiliary Output Voltages on Multiple-Output Converterson Multiple-Output ConvertersSaturable ReactorsSaturable Reactors Ae = Vs × td / ( Np × ∆B ) assume Np = 1. = 27.9*.827 µs / (1 * .4) = 57.7 mm^2Centering Auxiliary Output Voltages Centering Auxiliary Output Voltages on Multiple-Output Converterson Multiple-Output Converters ApplicationsApplications large industrial furnaces, welders and large industrial furnaces, welders and high-power voltage regulators.high-power voltage regulators.Important ConceptImportant Concept Depending on application, with Depending on application, with saturable reactors, decide to alter the saturable reactors, decide to alter the area or number of turn ratios to produce area or number of turn ratios to produce Vout.Vout.Auxiliary Supply Systems Auxiliary Supply Systems Provide power for control Drive circuits within the main switch-mode unit. Need to be common to input and output lines. Safety factors must be given  Creepage distance, isolation requirementsCreepage distance, isolation requirementsAuxiliary supply methods must be Auxiliary supply methods must be consideredconsideredAuxiliary Supply Systems Various auxiliary supply units Various auxiliary supply units  60 Hz Line Transformers 60 Hz Line Transformers  Energized before the main converter, allows Energized before the main converter, allows power available to the main switching mode. power available to the main switching mode.  Meets insulation and creepage requirements.Meets insulation and creepage requirements. Disadvantage: size & costDisadvantage: size & costAuxiliary Supply Systems Auxiliary ConvertersAuxiliary ConvertersTwo auxiliary power supplies from high Two auxiliary power supplies from high frequency flyback converters.frequency flyback converters.+ More efficient because energyIs returnted to the supply during Flyback period.Auxiliary Supply SystemsStabilized Auxiliary ConvertersStabilized Auxiliary ConvertersModifications Zener Diode,Q2, winding Modifications Zener Diode,Q2, winding P3P3Maintains constant frequencyMaintains constant frequency+ Maintains constant frequency. CanBe used as a clock.Auxiliary Supply SystemsHigh-efficiency auxiliary supply.High-efficiency auxiliary supply. Includes a bridge rectifier supply the Includes a bridge rectifier supply the converter & fan applicationconverter & fan application+ Most efficient supply system+ Useful in 110-220V applicationsParallel Operation of Voltage-Parallel Operation of Voltage-Stabilized Power SuppliesStabilized Power SuppliesVoltage Stabilized Power Supplies Voltage Stabilized Power Supplies  connected in parallel with high voltagesconnected in parallel with high voltages usually have small output resistancesusually have small output resistances big difference in current load!big difference in current load! desire equal distribution in currentdesire equal distribution in current may cause output power supply to be may cause output power supply to be overloaded! Domino Effect!overloaded! Domino Effect!Parallel Operation of Voltage-Parallel Operation of Voltage-Stabilized Power SuppliesStabilized Power SuppliesConfigurations of Power SuppliesConfigurations of Power Supplies Master Slave OperationMaster Slave Operation Master controls the parallel supplies. P-Master controls the parallel supplies. P-terminal and Transistor 3 control currentterminal and Transistor 3 control current KEY POINTS+ Similar output current - 20% Accurate - Limited to the number of supplies - If Master Fails, other units followParallel Operation of Voltage-Parallel Operation of Voltage-Stabilized Power SuppliesStabilized Power SuppliesConfigurations of Power SuppliesConfigurations of Power Supplies Voltage – Controlled Current SourceVoltage – Controlled Current Source P terminal link adjust for output voltage, R1 P terminal link adjust for output voltage, R1 and R2 sense output current. and R2 sense output current. KEY POINTS+ More accurate output current- Less percent of failureParallel Operation of Voltage-Parallel Operation of Voltage-Stabilized Power SuppliesStabilized Power SuppliesConfigurations of Power SuppliesConfigurations of Power Supplies Force Current SharingForce Current Sharing Compares Vref and V from R3 and R4 to maintain Compares Vref and V