Power electronics Chapter 5 DC to AC Converters Inverters
PPoowweerr EElleeccttrroonniiccss Chapter 5 DC to AC Converters ( Inverters )
PEREC Applications of Inverters 4 Conversion of electric power from dc type energy sources to ac type load Battery Photovoltaic cell (Solar cell) Fuel cell As a part of composite converter AC-DC-AC frequency converter(for AC motor drive) AC-DC-AC constant-voltage constant-frequency converter(for uninterruptable power supplies) AC-DC-AC Converters for induction heating AC-DC-AC-DC switching power supplies 2
Power Electron cs i 2 Applications of Inverters Applications of Inverters Conversion of electric power from DC type energy Conversion of electric power from DC type energy sources to AC type load sources to AC type load – Battery Battery – Photovoltaic Photovoltaic cell (Solar cell) cell (Solar cell) – Fuel cell Fuel cell As a part of composite converter As a part of composite converter – AC -DC -AC frequency converter (for AC motor drive) AC frequency converter (for AC motor drive) – AC -DC -AC constant AC constant -voltage constant voltage constant -frequency converter (for frequency converter (for uninterruptable uninterruptable power supplies) power supplies) – AC -DC -AC Converters for induction heating AC Converters for induction heating – AC -DC -AC -DC s witching power supplies itching power supplies
PEREC Outline 5.1 Commutation 5.2 Voltage source inverters 5.3 Current source inverters 5.4 Multiple- inverter connections and multi-level inverters 3
Power Electron cs i 3 Outline Outline 5.1 Commutation Commutation 5.2 Voltage source inverters 5.2 Voltage source inverters 5.3 Current source inverters 5.3 Current source inverters 5.4 Multiple 5.4 Multiple -inverter connections and multi inverter connections and multi -level inverters level inverters
PEREC 5.1 Commutation types Basic operation principle of inverters Load 15S pa classification of inverters Square-wave inverters(are discussed in this chapter) PWM inverters( will be discussed in Chapter 6) 4 the concept of commutation
Power Electron cs i 4 5.1 Commutation types Commutation types Basic operation principle of inverters Basic operation principle of inverters t uo i o t 1 t 2 Load S 1 S 2 S 3 S 4 i o uo Ud A classification of inverters A classification of inverters – Square -wav e inverters (are discussed in this chapter) inverters (are discussed in this chapter) – PWM inverters ( will be discussed in Chapter 6) PWM inverters ( will be discussed in Chapter 6) The concept of commutation The concept of commutation
PEREC 4 types of commutation ◆ Device commutation: Fully-controlled devices: GTO, IGBT, MOSFET Line commutation Phase-controlled rectifier Phase-controlled ac controller Thyristor cycloconverter 争 Load commutation 争 Forced commutation 5
Power Electron cs i 5 4 types of commutation types of commutation Device commutation: Device commutation: Fully -controlled devices: GTO, IGBT, MOSFET controlled devices: GTO, IGBT, MOSFET Line commutation Line commutation Phase -controlled rectifier controlled rectifier Phase -controlled AC controller controlled AC controller Thyristo Thyristor cycloconverter r cycloconverter Load commutation Load commutation Forced commutation Forced commutation
PEREC Load commutation T TT R iV TT b 4 Condition Load current is leading load voltage 4 Application: capacitive load, synchronous motor
Power E l ect r o n cs i 6 Load commutation Load commutation Condition: Load current is leading load voltage Condition: Load current is leading load voltage Application: capacitive load, synchronous motor Application: capacitive load, synchronous motor
Forced commutation (capacitance commutation C VT △w a Direct-Coupled With Coupling- Inductor 7
Power E l ect r o n cs i 7 Forced commutation Forced commutation (capacitance commutation) (capacitance commutation) Direct-Coupled Coupled With Coupling With Coupling-Inductor Inductor
PEREC Another classification of commutations 4 types of Commutations Device commutation For fully-controlled devices Self-commutation Forced commutation Line commutation or thyristors External commutation Load commutation
Power Electron cs i 8 Another classification of commutations Another classification of commutations Self-commutation commutation Device commutation Forced commutation Line commutation Load commutation 4 types of Commutations types of Commutations For fully-con trolled devices For thyristors External External commutation commutation
PEREC 2 classes of inverters Voltage Source Inverter Current Source Inverter S|) (CS|) + 长本V1+本W2 ⅥT1W C VVT C R lo L R D D T 2
Power Electron cs i 9 2 classes of inverters classes of inverters Voltage Source Inverter (VSI) Current Source Inverter (CSI)
PEREC 5.2 Voltage source inverter(Vsi) VD VD t二---1 Features e dc side is constant voltage, low impedance(voltage source, or bulk cap) t AC side voltage is square wave or quasi-square wave AC side current is determined by the load e Anti-parallel diodes are necessary to provide energy feedback path (freewheeling diodes, feedback diodes)
Power Electron cs i 10 5.2 Voltage source inverter (VSI) Voltage source inverter (VSI) + - C R L U d V1 V2 V3 V4 VD 1 VD2 VD3 VD4 u o io Features Features DC side is constant volt DC side is constant voltage, low impedance (voltage age, low impedance (voltage source, or bulk cap) source, or bulk cap) AC side voltage is square wave or quasi AC side voltage is square wave or quasi -square wave. square wave. AC side current is determined by the load. AC side current is determined by the load. Anti -parallel diodes are nece parallel diodes are necessary to provide energy ssary to provide energy feedback path. feedback path. (freewheeling diodes (freewheeling diodes , feedback diodes) , feedback diodes)
