scarica PDF - Locanda Fontanazza
Download
Report
Transcript scarica PDF - Locanda Fontanazza
Cree PV Inverter Tops 1kW/kg with
All-SiC Design
Alejandro Esquivel
September, 2014
Copyright © 2014, Cree Inc.
Presentation Outline
1. Meeting an Industry Need
a)
1kW/Kg
b)
No electrolytic capacitors in DC link
2. 50+kW SiC based PV Inverter Design
a) Boost Stage
b) Inverter Stage
c) Auxiliary Power Supply
3. Performance Comparison
Copyright
© 2013
Cree,
Copyright
© 2014,
Cree
Inc. Inc.
2
Cree SiC Power Portfolio – Products and Support
Reference Designs:
SiC Schottky Diodes:
• Solar - Boost and Inverter
• SMPS - PFC, ZVS, Flyback
• 600V, 650V, 1200V, 1700V
• 1A to 50A
• Packaged and bare die
C2M SiC MOSFETs:
• 1200V, 1700V
• 1Ω to 25mΩ (4A to 60A)
• Packaged and bare die
Gate Drivers:
• Single and dual
• Cree designed
• Partnered designs
Package Styles:
• TO-220
• TO-247
• Full-PAK
• DPAK (TO-252)
• D2PAK (TO-263)
• QFN
• Isolated TO-220
SiC Power Modules:
• 1200V, 1700V
• 100A to 300A Half-bridges
• 50A Six-pack
Bare die for power modules
Copyright © 2014, Cree, Inc.
pg. 3
Commercial PV installation 100kW – 1 MW
•
Commercial three-phase roof top system
•
Need for:
•
–
Small size
–
Light weight
–
High power density
–
Lower installed system cost
SiC devices enable the best solution to
achieve this need
Power density needed
> 1 kW/Kg
Copyright © 2014, Cree Inc.
4
What Is Used Today - Example
50 kW, TL3 series
Kaco Blueplanet 50.0 TL3
Full Power MPPT Voltage Range
480 – 850 VDC
Operating MPPT Voltage Range
200 – 850 VDC
No. Independent MPPT Input
Nominal output power
1
50 kW
CEC Efficiency
97.5%
Peak Efficiency
98.3%
Power Factor
> 0.99
Output Voltage
480 Vac
Operating Temperature Range
-30 °C to 60 °C
(de-rated > 45 °C)
Cooling
Forced convection
Weight
173 kg
Isolation Transformer
Volume
Copyright © 2014, Cree Inc.
Power density = 0.29 kW/Kg
Need: Increase this value > 3×
No
840 × 355 × 1360 mm
Cree SiC Technology
can achieve this…
5
Cree SiC Technology Enables ½ Volume and <1/3 Weight
Cree SiC based 3-ph, PV String Inverter comparison
Full Power MPPT
Voltage Range
480 – 850 VDC
450 – 800 VDC
Operating Voltage
Range
200 – 850 VDC
400 – 950 VDC
No. Indep MPPT Input
1
2
Nominal output power
50 kW
50 kW
CEC Efficiency
97.5%
97.8%
Peak Efficiency
98.3%
98.7%
Power Factor
> 0.99
> 0.99
Output Voltage
480 Vac
480 Vac
-30 °C to 60 °C
(de-rated > 45 °C)
-30 °C to 60 °C
(no de-rating)
Cooling
Forced air
Forced air
Weight
173 kg
50 kg
No
No
Operating Temperature
Range
Isolation Transformer
Volume (m3)
Copyright © 2014, Cree Inc.
0.41
840 x 355 x 1360 mm
0.21
700 x 300 x 1000 mm
SiC based 3-ph PV string
Inverter
Power Density = 1 kW/Kg
6
Cree All-SiC PV Inverter Reference Design Overview
Aux. Power Supply
Aux. Power Supply
450 to 800 VDC
2x MPPT channels
Driver
Driver
Channel B
~
Scalable to any numbers
of MPPT channels
MPPT Boost,
75kHz
480 Vac rms l-l
Channel A
LC line
Filter
825 VDC
3-ph Inverter,
48kHz
Control Plane
Copyright © 2014, Cree Inc.
7
3LT-Type Inverter Chosen for High Frequency Efficiency
2L
2L Si
3L-NPC Si
3L-T Si
2L SiC
3L-T SiC
100.0%
Power Stage Efficiency
99.5%
99.0%
3L-NPC
98.5%
98.0%
97.5%
97.0%
3L-T
96.5%
96.0%
0
5
10
15
20
25
30
35
40
45
50
Swithcing Frequency
Frequency (kHz)
Switching
(kHz)
Copyright © 2014, Cree Inc.
8
Inverter Schematic: All SiC Active Power Semiconductors
Input
Filter
4-ph interleaved
Boost Converter
2x C2M0080120D, SiC MOSFET in
parallel per phase leg.
2x C4D10120D, SiC MPS diodes in
parallel per phase leg.
Copyright © 2014, Cree Inc.
DC
Link
10x 700uF
600VDC film
3-ph T-Type
Inverter
2x C2M0025120D, SiC MOSFET in parallel
per phase leg upper and lower switch.
Output
Filter
3x 4uF, 470Vac film
3x 230uH, metglas core
1x C2M0025120D, SiC MOSFET per T-leg.
1x C5D50065D, SiC MPS Diode per T-leg.
9
50kW 4-Channel Boost Front End
Boost Chokes*
2pcs C2M0080120D
per each phase
EMI Filter Choke
MPPT
Ch A
Controller
MPPT
Ch B
Phase Gate
driver
Copyright © 2014, Cree Inc.
10
3-Level, T-Type Inverter Topology
3500 µF
270 µH
• Main lower & upper MOSFET position: 2x Cree 1.2kV SiC Mosfet, 50A, 25 mOhms
• Uses Cree SiC MOSFET body diode in main anti-parallel with main power switches
• T-Branch MOSFET position: 1x Cree 1.2kV SiC Mosfet, 50A, 25 mOhms
• T-branch Diode position: 2x Cree 650V, 50A, C3D50065D
Copyright © 2014, Cree Inc.
11
SiC System Efficiency v/s Si based system*
Better Overall efficiency
@ 1/3rd the weight
CEC Efficiency:
• Kaco – 97.5%
• Cree – 97.8%
* Independent test data for KACO BluePlanet 50.0 TL3 provided by gosolarcalifornia.ca.gov
Copyright © 2014, Cree Inc.
12
Thermal Images of Boost With 400VIn/800VOut at Full Load
C2D0080120D
C4D10120D
Boost Inductor
Part
Tc (°C)
Part #1
Tc (°C)
Part #2*
C2M0080120D
92.6
94.4
C4D10120D
67.5
64.9
Boost Inductor
69.7
* Note excellent sharing between paralleled devices.
Note: Testing is based on full load operation after 30min with fan to cool system
Ambient temperature = 25ºC
Copyright © 2014, Cree Inc.
13
Operating Temperature Data
Vin = 600 / 700VDC
Tamb = 22ºC
Po = 48 kW
LC output filter
Tcore = 66 (with potting)
103ºC (no potting)
Tcore = 38/35ºC
Tc = 54/53ºC
Tc = 70//68ºC
Tc = 39/38ºC
Tc = 61/54ºC
Copyright © 2014, Cree Inc.
Tc = 46/42ºC
14
60W SiC Based Auxiliary Power Supply
Cree 60W Single-end Flyback reference similar to that used in 50kW:
–
Input voltage: Wide input range 200Vdc to 1000Vdc
–
Output voltage: 12Vdc/4.5A; 5V/0.5A; -12Vdc/0.25A
–
Operating frequency: 75KHZ
PQ2625
transformer
Cree 1700V SiC MOSFET:
C2M1000170D
Cree 60W Aux Power Demo board with 1700V SiC MOSFET
Cree 1700V, 1Ω MOSFET:
• Higher blocking than available silicon
• Higher efficiency for cooler operation
• Enables higher reliability than comparable silicon designs
Copyright © 2014, Cree Inc.
pg. 15
All SiC 50kW PV String Inverter Test Assembly
Boost converter
DC Link Film Capacitors
2x 3.5mF, 1.1kV
Controller
Output Power = 47.8kW
Output Voltage = 492 Vac l-l rms
Output Current = 56A rms
DC link Voltage = 850 VDC
3-phase, balanced resistive load
Output filter
Copyright © 2014, Cree Inc.
Inverter Power stage
16
50kW Physical Specifications
All aluminum enclosure
30cm
100cm
Weight distribution shown in Kg
Total weight = 50 Kg
70cm
Copyright © 2014, Cree Inc.
17
Summary
Using SiC MOSFETs available today from Cree enables up to 3x the
power to weight ratio when compared to current Si based systems.
Higher Fsw reduces cost of the magnetics in the boost and output filter
while delivering improved efficiency compared to Si solutions.
Installing smaller, lighter inverters will lower installation costs.
Less parts and the use of film capacitors in the DC link can improve
reliability of the system.
Cree is developing a complete range of SiC discrete and module
devices to support the power conversion market.
SiC makes economic sense today!
Copyright © 2014, Cree Inc.
18
50 kW PV inverter – impact of “C2M” FETs
C2M0025120D MOSFET
Decreased BOM cost
Size, weight reduced
Efficiency improved
Reference: See Cree booth.
Copyright © 2014, Cree, Inc.
Size
Weight
Inverter
BOM
50% ↓
60% ↓
30% ↓
Inverter
install
cost
$/kW
savings
50% ↓
3-4% ↓
19