1 1 EE8412 Advanced AC Drive Systems Topic 4 Voltage Source Inverter Fed Drives ACS1000 MV Drive Source: ABB Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4 2 Lecture Topics • Steady-state Operation Modes • Two-level VSI Fed MV Drives • Neutral-point Clamped (NPC) Inverter Fed Drives • Cascaded H-Bridge (CHB) Inverter Fed Drives EE8412 Advanced AC Drive Systems Voltage Source Inverter Fed Drives Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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slides topic 4 - Ryerson University · 2006. 3. 30. · 2 3 • Operation Modes for ac motors 1. Constant Flux Operation: V / f = constant 2. Constant Power Operation: V = constant,
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EE8412Advanced AC Drive Systems
Topic 4Voltage Source Inverter Fed Drives
ACS1000 MV Drive Source: ABB
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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Lecture Topics• Steady-state Operation Modes
• Two-level VSI Fed MV Drives
• Neutral-point Clamped (NPC) Inverter Fed Drives
• Cascaded H-Bridge (CHB) Inverter Fed Drives
EE8412 Advanced AC Drive Systems
Voltage Source Inverter Fed Drives
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
2
3
• Operation Modes for ac motors
1. Constant Flux Operation: V / f = constant
2. Constant Power Operation: V = constant, f = variable
3. Voltage Compensation at low rotor speeds
V – stator voltage, f – stator frequency
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Constant Flux Operation
- If Φ > Φ rated , magnetic core will be saturated.
- If Φ < Φ rated , rated torque cannot be achieved.
Φ – motor magnetic flux (general term)
Toque = flux x current (general term)
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Constant Flux Operation
Induced emf in a magnetic circuit:E = 4.44 Φ N fwhere N – number of turns of the coil
Φ = E / ( 4.44 N f ) Φ = const → E / f = const → V / f = const
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Constant Flux Operation
eTRatedeT MaxeT
TeMax = constant
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Constant Power Operation
When f > frated → rotor speed n > nrated , but V should be kept const to avoid insulation breakdown
Since Φ = E / ( 4.44 N f )V = const and f ↑ → Φ ↓
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Constant Power Operation
eTRatedeT MaxeT
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Voltage Compensation at Low Rotor Speeds
To compensate the voltage drop on the stator resistors at low rotor speeds
Ratedf
RatedV
compV
Topic 4 Voltage Source Inverter Fed Drives
Steady-state Operation ModesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
10
Topic 4 Voltage Source Inverter Fed Drives
Two-level Inverter Fed DrivesEE8412
VDM5000 Two-level VSI Source: Alstom
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• System Block Diagram
fC
fL
dC
⎪⎭
⎪⎬⎫
Topic 4 Voltage Source Inverter Fed Drives
Two-level Inverter Fed DrivesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Main Functional Blocks1) Rectifier circuit- Phase shifting transformer- 12 pulse diode rectifier for line current THD reduction
2) DC circuit- Dynamic braking circuit- Capacitor Filter
3) Inverter circuit - PCBB: power converter building block- Series devices for high voltage operation
4) Motor side filter- dv/dt reduction- THD reduction- Common mode voltage elimination
Topic 4 Voltage Source Inverter Fed Drives
Two-level Inverter Fed DrivesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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• Inverter Topology PCBB
Topic 4 Voltage Source Inverter Fed Drives
Two-level Inverter Fed DrivesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
Source: Alstom
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• PCBB – Power Converter Building Block
sRpR
sC
Topic 4 Voltage Source Inverter Fed Drives
Two-level Inverter Fed DrivesEE8412
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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Topic 4 Voltage Source Inverter Fed Drives
NPC Inverter Fed DrivesEE8412
VDM6000 Multilevel NPC Inverter Source: Alstom
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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Topic 4 Voltage Source Inverter Fed Drives
NPC Inverter Fed DrivesEE8412
dCsC
sC
sD
sDsR
sL
dC
sL
sR
fC
fL
• Drive System Diagram
Switching devices: IGCTs
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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Topic 4 Voltage Source Inverter Fed Drives
NPC Inverter Fed DrivesEE8412
• Main Functional Blocks1) Rectifier circuit- Phase shifting transformer- 12 pulse diode rectifier for line current THD reduction
2) DC circuit - Capacitor Filter- di/dt clamping circuit
3) Inverter circuit- Three-level NPC inverter
4) Motor side filter- dv/dt reduction- THD reduction- Common mode voltage elimination
Textbook: Bin Wu, ‘High-Power Converters and AC Drives’, Wiley-IEEE Press, 2006, ISBN: 0-471-73171-4
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Topic 4 Voltage Source Inverter Fed Drives
NPC Inverter Fed DrivesEE8412
• Drive System Specifications
NoRegenerative braking capability
> 6 yearsMean time between failure (MTBF)
Forced air or liquidCooling
Standard: 10% for one minute every 10 minutesOptional: 150% for one minute every 10 minutes
Overload capability
Induction or synchronousMotor type
Sinusoidal (with output filter)Output waveform
> 0.95 ( Displacement power factor > 0.97)Input power factor
Typically > 98.0% (including output filter losses but excluding transformer losses)Drive system efficiency