《电力电子技术chapter04课件》由会员分享，可在线阅读，更多相关《电力电子技术chapter04课件（28页珍藏版）》请在金锄头文库上搜索。
1、Applications of InvertersConversion of electric power from DC type energy Conversion of electric power from DC type energy sources to AC type loadsources to AC type load BatteryBattery Photovoltaic cell (Solar cell)Photovoltaic cell (Solar cell) Fuel cellFuel cellAs a part of composite converterAs a
2、 part of composite converter AC-DC-AC frequency converter (for AC motor drive)AC-DC-AC frequency converter (for AC motor drive) AC-DC-AC constant-voltage constant-frequency converter (for AC-DC-AC constant-voltage constant-frequency converter (for uninterruptable power supplies)uninterruptable power
3、 supplies) AC-DC-AC Converters for induction heatingAC-DC-AC Converters for induction heating AC-DC-AC-DC switching power suppliesAC-DC-AC-DC switching power suppliesOutline4.1 Commutation4.1 Commutation4.2 Voltage source inverters4.2 Voltage source inverters4.3 Current source inverters4.3 Current s
4、ource inverters4.4 Multiple-inverter connections and multi-level inverters4.4 Multiple-inverter connections and multi-level inverters 4.1 Commutation typesA classification of invertersA classification of inverters Square-wave inverters (are discussed in this chapter)Square-wave inverters (are discus
5、sed in this chapter) PWM inverters ( will be discussed in Chapter 6)PWM inverters ( will be discussed in Chapter 6)The concept of commutationThe concept of commutationBasic operation principle of invertersBasic operation principle of invertersLoadS1S2S3S4iouoUd4 types of commutation4 types of commut
6、ation Device commutation: Device commutation: Fully-controlled devices: GTO, IGBT, MOSFETFully-controlled devices: GTO, IGBT, MOSFET Line commutation Line commutation Phase-controlled rectifierPhase-controlled rectifier Phase-controlled AC controller Phase-controlled AC controller Thyristor cyclocon
7、verter Thyristor cycloconverter Load commutation Load commutation Forced commutation Forced commutationLoad commutationLoad commutation Condition: Load current is leading load voltage Condition: Load current is leading load voltage Application: capacitive load, synchronous motor Application: capacit
8、ive load, synchronous motor Forced commutation Forced commutation (capacitance commutation) (capacitance commutation)Direct-CoupledDirect-CoupledWith Coupling-InductorWith Coupling-InductorAnother classification of commutationsAnother classification of commutationsSelf-commutationSelf-commutationDev
9、ice commutationForced commutationLine commutationLoad commutation4 types of Commutations4 types of CommutationsExternal External commutationcommutationFor fully-controlled devicesFor thyristors2 classes of inverters2 classes of invertersVoltage Source Inverter (VSI)Current Source Inverter (CSI)4.2 V
10、oltage source inverter (VSI) DC side is constant voltage, low impedance DC side is constant voltage, low impedance (voltage source, or bulk cap)(voltage source, or bulk cap) AC side voltage is square wave or quasi-square AC side voltage is square wave or quasi-square wave. wave. AC side current is d
11、etermined by the load. AC side current is determined by the load. Anti-parallel diodes are necessary to provide Anti-parallel diodes are necessary to provide energy feedback path.energy feedback path. (freewheeling diodes , feedback diodes) (freewheeling diodes , feedback diodes)+-CRLUdV1V2V3V4VD1VD
12、2VD3VD4uoioFeaturesFeaturesSingle-phase half bridge VSISingle-phase half bridge VSI The current conducting path is The current conducting path is determined by the polarity of load determined by the polarity of load voltage and load current. (This is true voltage and load current. (This is true for
13、analysis of many power electronics for analysis of many power electronics circuits.)circuits.)-RLUdiouoV1V2VD1VD2Ud2Ud2The magnitude of output square-wave voltage is UThe magnitude of output square-wave voltage is Ud d/2./2.uoUmiot1t2t3t4t5t6V1V2V1V2VD1VD2VD1VD2UG1UG2 Single-phase full bridge VSI Si
14、ngle-phase full bridge VSIOperation principleOperation principle+-CRLUdV1V2V3V4VD1VD2VD3VD4uoio The magnitude of output square-wave voltage is UThe magnitude of output square-wave voltage is Ud d. . The effective value of output voltage (or fundamental The effective value of output voltage (or funda
15、mental output voltage) can be changed by changing U output voltage) can be changed by changing Ud d. .uoUmiot1t2t3t4t5t6V1V2V1V2VD1VD2VD1VD2UG1,4UG2,3VD4VD3VD4VD34343VVVVFourier series extension of output voltageFourier series extension of output voltageMagnitude of output voltage fundamental compon
16、ent Magnitude of output voltage fundamental component Effective value of output voltage fundamental Effective value of output voltage fundamental componentcomponent Single-phase full bridge VSISingle-phase full bridge VSIQuantitative analysisQuantitative analysis(4-1)(4-1)(4-2)(4-2)(4-3)(4-3) Single
17、-phase full bridge VSISingle-phase full bridge VSI Output voltage control by phase-shiftOutput voltage control by phase-shift+-CRLUdV1V2V3V4VD1VD2VD3VD4uoioInverter with center-tapped transformerInverter with center-tapped transformerpush-pull inverterpush-pull inverter Three-phase VSIThree-phase VS
18、I 180180o o conduction conduction Dead time (blanking time) to Dead time (blanking time) to avoid “shoot through” avoid “shoot through” Three-phase VSIThree-phase VSIBasic equations to obtain voltage waveformsBasic equations to obtain voltage waveformsFor line voltageFor phase voltage of the loadThr
19、ee-phase VSIThree-phase VSIFourier series extension of output line-to-line voltageFourier series extension of output line-to-line voltageMagnitude of output voltage (line-to-line) fundamental component Magnitude of output voltage (line-to-line) fundamental component Effective value of output voltage
20、 (line-to-line) fundamental Effective value of output voltage (line-to-line) fundamental componentcomponentQuantitative analysisQuantitative analysis(4-8)(4-8)(4-10)(4-10)(4-11)(4-11)4.3 Current source inverter (CSI) DC side is constant current, high impedance (current source, or large inductor) AC
21、side current is quasi- square wave. AC side voltage is determined by the load. No anti-parallel diodes are needed. sometimes series diodes are needed to block reverse voltage for other power semiconductor devices.FeaturesFeaturesSingle-phase bridge CSISingle-phase bridge CSIParallel Resonant Inverte
22、r Parallel Resonant Inverter ACRLLdIdVT1VT2VT3VT4LT1LT2LT3LT4uoio Switching frequency is a little higher Switching frequency is a little higher than the resonant frequency so that the than the resonant frequency so that the load becomes capacitive and load load becomes capacitive and load current is
23、 leading voltage to realize current is leading voltage to realize load commutation. load commutation.Three-phase self-commutated CSIThree-phase self-commutated CSI 120 120o o conduction conductionThree-phase force-commutated CSIThree-phase force-commutated CSIThree-phase load-commutated CSIThree-pha
24、se load-commutated CSI4.4 Multiple-inverter connections and multi-level invertersSeries connection of 2 single-phase VSIsSeries connection of 2 single-phase VSIsSeries connection of 2 3-phase VSIsSeries connection of 2 3-phase VSIsMulti-level InvertersMulti-level InvertersWays to deal with higher vo
25、ltage and achieve better Ways to deal with higher voltage and achieve better waveformwaveform Series connection of multiple convertersSeries connection of multiple converters Series connection of multiple switch devicesSeries connection of multiple switch devicesMajor type of multi-level invertersMa
26、jor type of multi-level inverters Neutral point clamped multi-level inverterNeutral point clamped multi-level inverter Flying-capacitor multi-level inverterFlying-capacitor multi-level inverter Cascade H-bridge( series connected H-bridges)Cascade H-bridge( series connected H-bridges)In broad sense,
27、previously discussed series In broad sense, previously discussed series connection of multiple inverters is also called multi-connection of multiple inverters is also called multi-level inverter.level inverter.In narrow sense, only NPC and FC structures are In narrow sense, only NPC and FC structures are called multi-level inverters.called multi-level inverters.Neutral-Point-Clamped 3-level inverterNeutral-Point-Clamped 3-level inverterNeutral-Point-Clamped 5-level inverterNeutral-Point-Clamped 5-level inverterFlying-Capacitor 3-level inverterFlying-Capacitor 3-level inverter
