Application Note RC-Drives

RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Reverse Conducting IGBT for Drives
RC-Drives
Cost-Optimized IGBT
for Consumer Drive Application
Application Note
System Application IGBT
November 2009, Davide Chiola
Power Management
Discretes
1
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Edition Doc_IssueDate
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2010 Infineon Technologies AG
All Rights Reserved.
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Information
For further information on technology, delivery terms and conditions and prices, please contact the
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or system. Life support devices or systems are intended to be implanted in the human body or to support
and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the
health of the user or other persons may be endangered.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Table of Contents
1. Short description of the product family……………………………………….…………..…....4
2. Technology overview…………………………………………….……………………………..….5
3. Chip Shrink and power density increase…...…………………………………...………..…….7
4. Static and dynamic behavior………………………………………....….…………………...….8
4.1. Static behavior…………………………………………………........…………………….…....8
4.2. Dynamic behavior…………………………………….…………….……………………..…....9
4.3. Short Circuit capability…………………………………….…………………........................11
5. EMI Consideration and Rg selection……………………………..…………………………….12
6. Power Losses in a BLDC Motor…………………………………………………………….…..14
7. Thermal behavior ………………………………………………………..……………………….16
7.1. Washing Machine application test………………………...………………………………….16
7.2. Mounting and cooling considerations…………………………………………………...…...19
7.2.1. Surface mounted package …………………………….………………………...…...19
7.2.2. Straight leads package………………………..…………………………………..…..21
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
1. Short Description
As a further evolution of the TRENCHSTOP™ in the price-sensitive Consumer Drive market,
Infineon has released a new product family in the 600V voltage class. Purpose of this note is to
illustrate the key features of the new technology, highlight the potential benefit for the customer
as well as advantages over existing solutions, and to provide recommendations for the utilization
in an inverter motor drive circuit.
RC-Drives Product family
Max
Part
Package
number
Type
Inverter
Heatsink
Output
needed
IPAK
IKD04N60
DPAK
IKU06N60
IPAK
IKD06N60
DPAK
IKU10N60
IPAK
IKD10N60
DPAK
IKU15N60
IPAK
IKD15N60
DPAK
[email protected]
[email protected]
Power
[W]
IKU04N60
BVces
Vce(on)
Ets @
@
175C
175C
[email protected]
Typical
Typical
Tsc
Vgeth
[V]
[A]
[A]
[V]
[mJ]
[usec]
[V]
200
NO
600
8
4
1.85
0.40
5
5
600
YES
600
12
6
1.85
0.56
5
5
1000
YES
600
20
10
1.85
0.93
5
5
1500
YES
600
30
15
1.85
1.25
5
5
The product family can be used in a wide range of applications:
„ Appliance Motor Drives
… Air Conditioning Compressors, Fan
… Washing machines
… Refrigerator Compressors
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
… Vacuum cleaners
… Dishwashers
… Ventilation Fans
„ General purpose Motor Drives
„ Pumps
2. Technology Overview
Infineon has pioneered over the last 20 years the Trench Field Stop IGBT Technology
(TRENCHSTOPTM), combination of Field Stop concept in thin wafer technology and ´trench gate,
with voltage classes spanning from 600V to 6500V. The RC-Drives technology is based on the
established Trench Field Stop IGBT platform and tailored to the needs of the low-cost highvolume consumer market: the freewheeling diode is monolithically integrated in the IGBT chip,
thus achieving substantial Si area saving:
Figure 1: Reverse Conducting IGBT construction
5
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
The chip construction is similar to the previously released RC-H IGBT (Reverse Conducting for
Induction Heating), however the integrated diode had to be improved in order to sustain hard
switching conditions typical of inductive load in motor drive applications. This is realized by
engineering the carrier profile inside the chip:
„ Reduction of anode efficiency to reduce Qrr, Irr
„ Lifetime killing process to speed-up depletion of the base from free-carrier
„ Increase of cathode n-emitter efficiency to increase diode softness.
Thanks to these modifications, Qrr and Irr during reverse recovery are reduced, insuring reduced
power dissipation at IGBT turn-on in half bridge hard-switching voltage source inverters typical of
motor drives.
Beside Si area saving, additional advantages of the RC-Drives technology are:
„ Reduction of wafer testing costs
„ Reduction of assembly costs (single pass in chip bonding)
„ More degrees of freedom in package layout
„ Small „diodes“ can still be bonded with „thick“ bond wires
„ Low thermal resistance of the diodes thanks to wider conduction area
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
3. Chip shrink and power density increase
Thanks to the reduced total chip size, packages of reduced footprint can be used for the same
current rating of equivalent DuoPAK Products, thus allowing a substantial power density
increase:
Conventional
Footprint
Height
RC-
Footprint
Height
Footprint
Height
technology
[mm2]
[mm]
Drives
[mm2]
[mm]
reduction
reduction
TO-220
157
4.5
IPAK
39
2.3
-75%
-49%
D²PAK
106
4.5
DPAK
39
2.3
-63%
-49%
Note: To keep the Tj below 175°C, additional cooling effort may be needed.
As a reference, refer to options provided in Chapter 7.
Smaller package means less board spacing and compact system design. Although board
spacing is normally not an issue in House Appliances, newer generation of Products could take
advantage of a reduced board real estate for the power section: for example washing machines
with increased drum size that must maintain the external outline, Industrial fan of Refrigerator
compressors were the inverter board is mounted directly close to the motor.
DPAK
3phase
Figure 2: example of board space saving from RC-Drive in DPAK and IPAK package comparison
7
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
4. Static and Dynamic Behaviour
4.1 Static Behaviour
The RC-Drives IGBT is optimized for low Vcesat, because the conduction losses are dominant in
the switching frequency range typical of motor drive application (4~16 kHz). Low Vcesat allows:
„
Reduced losses and improve system efficiency
„
Reduced number of devices in parallel for high power systems
„
Reduced heatsink size
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 3: Output characteristics of RC-Drives IGBT.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
4.2 Dynamic Behaviour
Due to the optimization for low Vcesat, the RC-Drives tends to show long tail currents at turn-off
(Figure 4).
Figure 4: Turn-off Transient Waveforms
The turn-off losses at same dV/dt are higher compared to the DuoPAK (IKP06N60T) and to
Competitor 1. These devices show however some non linear dI/dt characteristics that would
generate harmonics of the radiated EMI noise (see next chapter). Competitor 2 shows similar
turn-off current waveform resulting in similar turn-off losses as the RC-Drives. A trade-off chart
Vcesat - Eoff is summarized in Fig. 5.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Trade Off IGBT @ T=175°C
@dVcesat/dt=7kV/µs
400
RCDrive -Ipak
350
TO220
Eoff [µJ]
300
250
IGU06N60R
TrenchStop - TO220
200
IKP06N60T
150
Competitor 2
TO220
100
Competitor 1
50
0
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
Vce(sat) [V]
Figure 5: Trade-off Vcesat - Eoff
4.3 Short Circuit Capability
The monolithic integration of the antiparallel diode does not degrade the short circuit capability in
comparison with the TRENCHSTOPTM. The RC-Drives is rated at tsc=5usec at Tj=150°C,
Vge=15V, Vcc=400V.
The destruction mechanism is thermal run-away after successful turn-off (Figure 6), confirming
the robust latch-up free Trench cell design. The failure mechanism of thermal destruction was
validated by electro-thermal simulation: for long enough SC pulses, the device cannot dissipate
the energy of the pulse, the Junction temperature increases and the Ices leakage is running
away.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
V, I
R. Weiss MP#4 Zeljko-Ansteuerung
5
4
Ug ref
Uce ref
Ic ref
Ug dut
Uce dut
Ic dut
Vge
3
2
Vce
1
0
-1
-2
Ic
-3
-4
-5
0
1
2
3
4
5
IGU06N60R_#C
Vce 100V/div, NP -4
Ic 5A/div, NP -4
Vgs 5V/div, NP 0
Vce [V]: 400 Rg [Ohm]: 23
Ice [A]: NaN Vge [V]: 15
6
7
8
9
10 t [µs]
IGU06N60R
tdoff [ns]: 0
tf [ns]: 0
tf Tang. [ns]: 0
dUce/dt [V/ns]: 0
dIc/dt [A/µs]: 0
Vce 100V/div, NP -4
tdoff [ns]: 0
Ic 5A/div, NP -4
tf [ns]: 0
tf Tang. [ns]: 0
dUce/dt [V/ns]: 0
dIc/dt [A/µs]: 0
Eoff [mJ]: 0
Vgs 5V/div, NP 0
Vce [V]: 400
Eoff [mJ]: 0
Ice [A]: NaN
Rg [Ohm]: 23
Vge [V]: 15
T [°C]: 150
T [°C]: 150
Figure 6: Typical short circuit waveform of a failing device. Thermal failure is happening well after
turn-off. Vge=15V, Vce=400V, Tj=150°C.
5. EMI consideration and Rg section
EMI is mainly driven by rate of change of voltage and current during switching events.
Switching behavior as a function of Rg and Tj was investigated to assess the EMI performance in
a real inverter circuit. Results for the RC-Drives are compared with the previous generation
TRENCHSTOPTM and other competitors. Specifically the dV/dt behavior is plotted in Figure 7.
12
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Turn-off dU/dt
Turn-on dU/dt
Vce=400V Ic=6A Rg=24Ohm
Vce=400V Ic=6A Rg=24Ohm
0
20
18
IGU06N60R
IKP06N60T
Competitor1
Competitor2
-5
IGU06N60R
IKP06N60T
Competitor1
Competitor2
dUceoff/dt [V/µs]
dUceoff/dt [V/µs]
16
14
12
10
RCDrive
RCDrive
-10
-15
-20
8
-25
6
4
0
50
100
150
200
-30
0
50
T [°C]
Turn-off dU/dt
Vce=400V Ic=6A T=175°C
Turn-on dU/dt
14
150
200
Vce=400V Ic=6A T=175°C
0
12
IGU06N60R
IKP06N60T
Competitor1
Competitor2
-5
10
Uceon/dt [V/ns]
dUceoff/dt [V/µs]
100
T [°C]
8
6
4
-10
-15
-20
2
IGU06N60R
IKP06N60T
Competitor1
Competitor2
-25
0
0
50
100
150
200
0
50
100
150
200
Rg [Ohm]
Rg [Ohm]
Figure 7: dV/dt as a function of Tj and Rg.
The RC-Drives show the lowest dV/dt over the entire temperature range that will translate in
lower high frequency harmonics of radiated EMI noise. The Rg can be reduced in order to
reduce switching losses still maintaining low EMI.
13
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
6. Power Losses in a BLDC Motor
On the basis of the measured conduction and switching losses, the power losses of a real 3phase voltage source Inverter driving a BLDC motor were estimated. The modulation type is
hard switching (Fig 8), were both conduction and switching losses are playing a significant role:
Hard Switching Modulation
Figure 8: Hard switching of a 3-phase voltage source inverter
Vcc=400V, Rg =24 Ohm, Iout=6A. hard switching
Simulations results for the 6A RC-Drives in IPAK are shown in Fig 9. At 4 kHz the conduction
losses are dominating the overall losses, and the RC-Drives show low power dissipation aligned
with competitors devices in TO-220 package. At 16 kHz the switching losses are taking over,
14
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
and the RC-Drives is penalized. Rg is set to 24 Ohm for all devices, a reduction of Rg for the RCDrives would have reduced the power dissipation in this case. The TRENCHSTOPTM in TO-220
P
package shows the lowest losses for fsw<15 kHz.
B6-Inverter Hardswitching
Tj = 25°C
3.5
IKU06N60R
3.3
Ptot [W]
IFX RCD
IPAK
IKP06N60T
IRGB4045
Comp.1
3.0
2.8
IFX Duopak
TO220
Comp.2
STGP10NC60
2.5
2.3
2.0
1.8
1.5
0
2
4
6
8
10
12
14
16
18
20
18
20
f [kHz]
B6-Inverter Hardswitching
Tj = 175°C
3.5
IKU06N60R
3.3
IKP06N60T
Ptot [W]
3.0
IRGB4045
Comp.1
2.8
Comp.2
STGP10NC60
2.5
2.3
2.0
1.8
1.5
0
2
4
6
8
10
f [kHz]
15
12
14
16
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
BLDC Motor, Hard Switching modulation
400V, Ic=6A, DC=0.65, Tj=175C
BLDC Motor, Hard Switching modulation
400V, Ic=6A, DC=0.65, Tj=175C
fsw=4kHz
4.0
Diode sw.
3.5
Diode cond
IGBT sw
IGBT cond
2.5
2.0
1.5
1.0
3.0
Power losses (W)
Power Losses (W)
Diode sw.
3.5
IGBT sw
3.0
fsw=16kHz
4.0
Diode cond
IGBT cond
2.5
2.0
1.5
1.0
0.5
0.5
0.0
0.0
IKU06N60R
IRGB4045
Comp.1
STGP10NC60
Comp.2
IKP06N60T
IKU06N60R
IRGB4045
Comp.1
STGP10NC60
Comp.2
IKP06N60T
Figure 9: Power loss vs. switching frequency and loss breakdown for individual switch
7. Thermal Behaviour
7.1 Washing Machine Application Test.
In order to verify the thermal behavior of the RC-Drives, an application test was performed in a
commercial AEG Washing machine. The original Electrolux board was equipped with TO-220
FullPAK device from competition. The HS and LS TO-220 FullPAK for one phase were replaced
with RC-Drives in IPAK (Fig 10). Thermal foil was added to insulate the package from the
heatsink.
16
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 10: Application test set-up
For the case temperatures of the high side and low side IGBTs a thermocouple is inserted on a
small hole drilled in the molding compound on the side of the package. The resulting
temperature readings are very close to the junction temperature. For the heatsink temperature a
small hole is also drilled in the heatsink in the vicinity of the low side device, and a third
thermocouple is inserted. Temperatures are recorded during a “20 min” Washing-RinsingSpinning cycle with approx 5 Kg of load, 1200 rpm and 30°C water temperature (Fig11). The
difference between junction and ambient temperature Tj and Ta is directly related to the power
losses and thermal resistance:
Tj -Ta = (Rthjc + Rthcs ) x Ptot + Rthsa x Ptot x 6
Were Ptot= Average Power loss IGBT + Diode for one device.
The result (Fig. 12) shows only 15 °C maximum increase in Tj of the RC-Drives in IPAK in
comparison with the commercial solution in TO-220 FullPAK from competition, and 90°C of Tjmax.
In a worst case of a max Ta in a real application of approx 70°C, the resulting Tjmax would be
approx. 135°C, well within the Tjmax specification of 175°C.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Case Temperature Profile during "20min" cycle
Infineon RCD in I-pak IKU06N60R
100
RCD_GHS
90
RCD_QLS
RCD_Heatsink
80
Washing
12 sec rotation
5 sec stop
12 sec reverse direction
Rinsing ?
Rinsing
Spinning
Termp (°C)
RCD_Ambient
70
60
2:30 min
4:15 min
1:36
3.30 min
i
50
11:35 min
Pump
waterout
40
30
20
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
Time (sec)
Figure 11
Delta Case-Ambient Temperature Profile during "20min" cycle
RC-Drives vs Competitor 2.
Delta Tc,LS - Ta
70
Rinsing
RC-Drives LS
60
Competitor2 LS
Termp (°C)
50
Washing
12 sec rotation
5 sec stop
12 sec reverse direction
Rinsing
Spinning
40
30
Additional 15°C
for the RC-Drives
Pump
waterout
20
Additional 10°C
for the RC-Drives
10
0
0
100
200
300
400
500
600
700
800
Time (sec)
Figure 12
18
900
1000
1100
1200
1300
1400
1500
1600
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
7.2 Mounting and Cooling Consideration
As a cost saving option for consumer drive, the RC-Drives are intended to be a replacement of
bigger packages to provide good enough performance in the selected application. Below we
provide examples of mounting options for both surface mount (DPAK) and straight leads (IPAK)
versions.
7.2.1 Surface Mount
This package version is normally found in low power system (up to 300W), were simple surface
mount assembly (soldering + reflow) allows a good cost saving for the power section of the
inverter. Output power is limited by the thermal resistance of the package mounted directly on
the PCB (TjA up to 50 °C/W), and power dissipation / switch must be kept within 2W approx.
In the example below (Figure 13) we compare a commercial board for refrigerator compressors
to a 200W RC-Drives demoboard developed in-house for compressors, fans and pumps:
Commercial 200 W compressor board – D²PAK
RC-Drive demoboard - DPAK
Figure 13
19
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
In order to improve the heat dissipation, thermal vias are realized in the PCB under the device
case, in order to allow a better heat dissipation in case a heatsink is mounted on the opposite
side of the board (Figure 14 and 15). The heatsink is insulated by Thermal foil.
Figure 14: Thermal vias for an improved thermal design
20
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 15: Example of heatisink mounting
7.2.2. Straight Leads mounting
Vertical insertion of straight leads packages are typically found in higher power systems
(600~800W), were normally TO-220 FullPAK are used anchored to heatsink. Here the RCDrives in IPAK can replace such packages, but an insulation foil has to be used because the
drain of the DPAK is not isolated. An example is provided in Figure 16, were the Electrolux
board of a commercial AEG Washing machine is used to test different IPAK mounting concepts.
21
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 16: Commercial board with TO-220 FullPAK + clips
To improve the mounting for the IPAK, the heatsink design was changed to allow clips screwing
(Figure17). The angle of the clips is now optimized for the IPAK size and a uniform pressure of
the device on the heatsink is achieved. Insulating foil is added. Against vibrations typical on a
washing machine, bolts can be added to secure the clips.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 17: Mounting the clips with nuts and bolts.
Different heatsink / clips combinations are also showed in Figure 18 and 19:
Figure 18: different Clips / heatsink / foil combination for mounting of the IPAK
23
RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
Figure 19: no bolts are used in this case, but direct screwing on the Aluminum heatsink.
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RC-Drives
Cost-Optimized IGBT for Consumer Drive Application
w w w . i n f i n e o n . c o m / i g b t s
25
Published by Infineon Technologies AG
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