Improve the Efficiency in AC-Drives:
New Semiconductor Solutions
and their Challenges
Klaus Vogel and Anastasia Brodt
Infineon Technologies AG
Adalberto Rossa
WEG Automation R&D Center
Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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2
Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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3
Motivation
› Energy costs
› Efficiency Classification
› Standard Efficiency Measurement
› Lower cooling effort
Source: 2011, PCIM, Koeneke, Highly Eff. Inverter Using SiC_JFET
Source: http://shop.csa.ca/en/canada/energy-efficiency/c838-13/invt/27035302013
2015-09-14 Klaus Vogel
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4
Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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5
Inverter Efficiency Classification
and the EN 50598-2 “Energy efficiency indicators
for power drive
systems and motor starters”
22kW:
2015-09-14 Klaus Vogel
375W
1125W 1500W
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6
Motor isolation and the IEC 60034-18-41
Maximum peak voltages, du/dt and minimum tr for WEG inductions motors
Source: WEG Industries
2015-09-14 Klaus Vogel
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7
Evaluation of tr according IEC 60034-18-41
2015-09-14 Klaus Vogel
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8
Switching Energy and dV/dt
IGBT Turn-Off Example
IC
dV/dt
VCE
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9
Lowest switching losses possible at highest
dV/dt
Eoff, Eon = f(du/dt)
0,07
Eoff, Eon/I [mJ/A]
0,06
Eoff SiC Switch
Eon SiC Switch
Eoff_min HS3 + SiC FWD
Eon_min HS3 + SiC FWD
0,05
0,04
0,03
0,02
0,01
0,00
0
10
20
30
40
50
60
70
du/dt [kV/µs]
2015-09-14 Klaus Vogel
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Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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11
Drives System and Inverter Topologie
EcoDesign
motor efficiency
Only:
Long motor cables
High-speed motors
2015-09-14 Klaus Vogel
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12
Two different 22kW drives applications
2015-09-14 Klaus Vogel
GPD
High-Speed
Max Output
frequency [Hz]
50
1500
Switching
frequency [kHz]
5
16
Cos phi
0.85
0.56
Output current
[A]
40.5
60.0
IGBT Module
FS75R12KT4
FS150R12KT4
Topology
2-Level
2-Level
TH [°C]
90
90
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22kW GPD in standard Si-Topology
Total losses: 621W
Efficiency: 97.2%
Related
Focustoofsemiconductor
this study
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Overview 22kW Drives
GPD
High Speed
Total Losses [W]:
621
1436
Percentage Semiconductor Losses Inverter Stage [%]
52
67
Efficiency [%]
97,2
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93,5
15
Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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16
Alternatives to increase the efficiency
2015-09-14 Klaus Vogel
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17
GPD - Losses at 22kW output inverter stage
2015-09-14 Klaus Vogel
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18
GPD – Achievable efficiency level and cooling
effort reduction
2015-09-14 Klaus Vogel
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19
High-Speed Drives – Achievable efficiency
level and cooling effort reduction
2015-09-14 Klaus Vogel
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Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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Degree of freedom 1:
22kW static losses as a function of SiC Area
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Degree of freedom 1:
SiC at 7 kV/µs
2015-09-14 Klaus Vogel
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Degree of freedom 2:
SiC at maximum speed and high fs
Combine high switching frequency with highest efficiency. SiC example:
Efficiency = f(fSW) for 22kW GPD
Semiconductor
Inverter Efficieny [%]
100
60A Full SiC
FS75R12KT4
99
98
97
96
95
0
5
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Switching frequency [kHz]
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Degree of freedom 2:
SiC at maximum speed and high fs
Combine high switching frequency with highest efficiency
GPD example with SiC:
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Degrees of freedom coming with
dV/dtmax at 7kV/µs
and
big SiC Area
High switching
frequency and
max. switching speed
Reduce significantly
static losses
Small Sinusoidal filter at
high efficiency level
1. Increase Efficiency
2. Reduce cooling effort
3. No new EMC challenges
4. Maintain todays usual voltage
rise time
2015-09-14 Klaus Vogel
1. No high dv/dt at the motor windings
2. No issues with long motor cables
3. Cables without special shielding saving
installation costs
4. Increasing of the motor bearings
lifetime
5. Reduction of motor losses
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Content
1
Motivation
2
Related Standards
3
Efficiency in Drives
4
Impact with SiC and 3-Level
5
Degrees of freedom coming with SiC
6
Summary
2015-09-14 Klaus Vogel
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Summary
22kW GDP Example:
22kW:
375W
1125W 1500W
Best solution
Std. solution
446W
621W
2015-09-14 Klaus Vogel
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Summary
Big efficiency improvement possible using new topology or semiconductor technology
3-Level solution:
Lower output voltage amplitude Motor friendly
dv/dt filter smaller If required
Lower EMI Lower VCM
Complex Gate Control !! Development effort, FIT-Rate
Complex PWM Control !! Development effort
2-Level SiC solution:
Simple PWM Control Existing design
Highest efficiency level achievable Lowest Operation Costs
Low cooling effort Passive cooling possible or highest power density
Fast switching: Low inductance design necessary !! Development effort
Fast switching: dv/dt >> 7kV/µs !! Filter (dV/dt or sinus) and/or improved
motor insulation
The economical aspects on system level will decide about the success of new
solutions in drives application
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2015-09-14 Klaus Vogel
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Evaluated solutions
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2015-09-14 Klaus Vogel
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Evaluation of tr according IEC 60034-18-41
SiC Switch
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Benefits of SiC transistors
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2015-09-14 Klaus Vogel
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