Momentary High-Z Gate Driving (MHZGD) at
Miller Plateau for IGBT Load Current Estimationfrom Gate Driver
Hiromu Yamasaki, Ryunosuke Katada, Katsuhiro Hata, and Makoto Takamiya
The University of Tokyo, Tokyo, Japan
Abstract—To eliminate a load current (IL) sensor required todetermine optimum gate driving parameters of a digital gate
driver for IGBTs and to estimate IL from the gate driver, amomentary high-Z gate driving (MHZGD) method is proposed.
In MHZGD, the output voltage (VOUT) of the gate driver ismeasured at Miller plateau when the gate driving current (IG) iszero for a short time (1 μs in this paper), and IL is estimated fromthe measured VOUT. MHZGD is suitable for the digital gate
driver, because the IL estimation is not affected by IG, and has
the advantage of not affecting the switching operation of IGBT.
In the double pulse test of IGBT at 300 V, by using one-pointcalibration at IL = 20 A at 25 °C, the measured IL estimation
errors of three IGBTs in the range from 5 A to 80 A are within+ 7.7 % / − 7.0 % at 25 °C, 75 °C, and 125 °C, which suggeststhat MHZGD can estimate IL with acceptable error against
IGBT and temperature variations.

without depending on IG. VOUT and VGE,INT, however, are notequal due to IG (RG,INT + RG,EXT) drop, where RG,INT and RG,EXT
are the internal gate resistance of IGBT module and theexternal gate resistance, respectively. In [8], the relationshipbetween IL and the external gate-emitter voltage (VGE,EXT) of
IGBT module depends on IG, which is not acceptable in
DGDs, because IG dynamically changes in DGDs. In [9], IL
is estimated from IG, which cannot be used in the currentsource based DGDs [1], because IG is controlled by digital
inputs and does not depend on IL. To solve the problems, inthis paper, a momentary high-Z gate driving (MHZGD)
method is proposed to estimate IL from VOUT without
depending on IG.

Keywords—digital gate driver, IGBT, load current, estimation

Figs. 2 and 3 show waveforms of a conventional gate
driving and the proposed MHZGD at turn-on and turn-off of
IGBT, respectively. In the conventional gate driving, VOUT at
the Miller plateau is not equal to VGE,INT due to IG (RG,INT +RG,EXT) drop. In MHZGD, however, IG is zero during t2 (1 μs
in this paper) and the operation starts after turn-on or before
turn-off. Zero IG for a short time is the origin of name of
MHZGD. In this work, the zero IG is achieved using thecurrent-source based DGD [1]. Even if the current-source
based DGD is not available, any gate driver can implement
MHZGD if a switch is added between the output of the gate
driver and the gate of IGBT, and the switch is turned off for ashort time. The period of t2 must be after the switching of thecollector current (IC) and the collector-emitter voltage (VCE) atturn-on (Fig. 2) and before the switching of IC and VCE at turnoff (Fig. 3) to avoid the increase of switching loss, and must
be within the Miller plateau of VGE,INT. During t2, VOUT is equal
to VGE,INT because of zero IG, and this VOUT is defined as
VOUT,MHZ. Therefore, in MHZGD, IL can be estimated fromII. PROPOSED MOMENTARY HIGH-Z GATE DRIVING(MHZGD)I. INTRODUCTION
Active gate driving of IGBTs, where the gate driving
current (IG) is dynamically controlled during the turn-on/off
transients, is a promising technology to solve theconventional trade-off between the switching loss and thecurrent or voltage overshoot of IGBTs. Digital gate drivers(DGDs) [1] are useful for the active gate driving, because IG
is programmable with gate driving parameters using asoftware. In DGDs, however, gate driving parameters require
information on load current (IL) and junction temperature (TJ),
because the optimum parameters depend on IL and TJ [2].
Since adding a current sensor (e.g., current transformer, shunt
resistor [3-4], and Rogowski coil [5-7]) to measure IL is costly,
IL estimation method, which can be integrated on DGD IC, ispreferable in terms of cost reduction.
Fig. 1 shows a circuit schematic of a gate driver and an
IGBT. IL can be estimated by Miller plateau voltage of theinternal gate-emitter voltage (VGE,INT) of IGBT, because theplateau voltage depends on IL [8]. The target of this work is
to estimate IL from the output voltage (VOUT) of the gate driver

In

t1
IG

IGBT
moduleIC, IL

15V

In

IG

RG,EXT

RG,INT

GD

VOUT

VGE,EXTc
978-1-7281-6344-4/21/$31.00 2021
IEEE

IG

0A

VOUT
VGE,INT

IC

VCE

VCE

VOUT
VGE,INT

VGE,INT

0V

IL

IC

0A

0V

(a) Conventional

t2

0A

15 V

VOUT

0V

VGE,INT

Fig. 1. Circuit schematic of gate driver and IGBT.

In

15 V

VOUT
MHZGD

VGE,INT
VOUT,CONV
VOUT,MHZ
IL

0A

VCE

0V

(b) Proposed momentary
high-Z gate driving (MHZGD)

Fig. 2. Waveforms of conventional gate driving and proposed
MHZGD at turn-on of IGBT.

1686

In

In
t1

IG

IG

0A

0A

15 V

15 V V

VOUT
VGE,INT

VOUT

IL
IC

VCE

VOUT
VGE,INT

VGE,INT
0V

0A

VOUT

VOUT,MHZ
VOUT,CONV

IL

0V

IC

VOUT :3 V/div
VOUT,MHZ
MHZGD
2 Ps/div

VCE:50 V/div

0A

VCE

0V

(a) Conventional

t2

t1

GE,INT

MHZGD

IG = 43mA

IC:10 A/div

t2

0
0V

(b) Proposed momentary
high-Z gate driving (MHZGD)(a)Fig. 3. Waveforms of conventional gate driving and proposed
MHZGD at turn-on of IGBT.

VOUT,MHZ (= VGE,INT). The measurement of VOUT,MHZ can bedone with an A/D converter, which can be integrated on DGD
IC. VOUT just before the period of t2 is defined as VOUT,CONV.

Digital gate
driver IC

IGBT module

IC:10 A/div
VOUT :3 V/div

MHZGD
VOUT,MHZ

0t1
VCE:50 V/divt2(b)Fig. 5. Measured waveforms at IL = 50 A, TJ = 25 °C, and t2 = 1
μs. (a) Turn-on. (b) Turn-off.

VOUT [V]15
IL = 80 A

10

5A

5

0

50 A

MHZGD IGBT1
TJ = 25 ºC
IG = 43 mA

0

5
10Time [Ps]

15

(a)

15

VOUT [V]Fig. 4 shows the photo of the measurement setup of the
double pulse test of the IGBT module (2MBI100VA-060-50,
600 V, 100 A) at 300 V to demonstrate MHZGD. The currentsource based DGD IC [1] drives the low side of the IGBT
module. RG,EXT is zero. In this paper, IL estimations at different
IGBT modules, TJ’s, and IG’s are discussed. Figs. 5 (a) and (b)show the measured waveforms at IL = 50 A, TJ = 25 °C, and t2= 1 μs during the turn-on and turn-off of IGBT, respectively.
VOUT,MHZ generated by MHZGD is clearly observed. Please
note that MHZGD has no effect on the switching loss andovershoots of IC and VCE. Figs. 6 (a) and (b) show themeasured VOUT waveforms of IL = 5 A, 50 A and 80 A at TJ =25 °C during the turn-on and turn-off of IGBT, respectively.
VOUT,MHZ increases with increasing IL. Figs. 7 (a) and (b) show
the measured VOUT waveforms of two different IG’s at IL = 50
A and TJ = 25 °C during the turn-on and turn-off of IGBT,
respectively. Please note that VOUT,MHZ’s of the two curves are
the same independent of IG. Figs. 8 (a) and (b) show themeasured IL dependence of VOUT,CONV and VOUT,MHZ of two
different IG’s at TJ = 25 °C during the turn-on and turn-off of
IGBT, respectively. VOUT,CONV − VOUT,MHZ is 0.68 V at IG = 78
mA during the turn-on and VOUT,MHZ − VOUT,CONV is 0.68 V at
IG = 78 mA during the turn-off, which are reasonably
explained by IG × RG,INT = 78 mA × 9 Ω = 0.70 V. Both
VOUT,CONV and VOUT,MHZ depend on IL. VOUT,CONV depends on
IG, while VOUT,MHZ does not depend on IG, which clearly showsthat proposed MHZGD estimates IL independent of IG. As
expected, the curve of VOUT,MHZ in Fig. 8 (a) matches the curveof VOUT,MHZ in Fig. 8 (b) and the proposed MHZGD works for

IG = 39mA

2 Ps/div

IL = 80 A

10

5A

5

0

IGBT1
TJ = 25 ºC
IG = 39 mA

0

MHZGD

50 A

5
10
Time [Ps]15(b)Fig. 4. Photo of measurement setup of double pulse test of IGBT
module.

Fig. 6. Measured VOUT waveforms of IL = 5 A, 50 A and 80 A at
TJ = 25 °C. (a) Turn-on. (b) Turn-off.

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)

1687

both turn-on and turn-off. Therefore, only the turn-on case will
be discussed in the following sections.

15

VOUT [V]IG = 78mA
VOUT,MHZ

MHZGD

5

0

III. LOAD CURRENT ESTIMATION USING MHZGD

43mA

10

0

IGBT1
IL = 50 A
TJ = 25 ºC

5
10Time [Ps]15(a)VOUT [V]

15
39mA

10
5

0

MHZGD

IGBT1
IL = 50 A
TJ = 25 ºC

IC

k (TJ ) ^VGE,INT  VTH (TJ )`VOUT,MHZIL

k (TJ ) ^VOUT,MHZ  VTH (TJ )`IG = 78mA

0

5
10Time [Ps]15

VOUT,CONV and VOUT,MHZ [V]IG = 43 mA
VOUT,CONV9

VOUT,MHZ

8
0.68 V

7

10

20

E

Turn-on
IGBT1
TJ = 25 ºC

30 40 50 60 70
Load current (IL) [A]80

90

VOUT,CONV and VOUT,MHZ [V]

(a)

(3)
(4)

^

`

Input: Measured VOUT,MHZ and TJ

IG = 39 mA

IL

9

VOUT,MHZ^V

OUT,MHZ

VTH (TR )Turn-off
IGBT1
TJ = 25 ºC

7
0.68 V
20

E

E

VOUT,CONV10§T ·k (TR ) ¨ J ¸© TR ¹` ^VTH (TR )  J TJ  TR `Dk(TR )

80

E

IG = 78 mA

10

6

§T ·
k (TR ) ¨ J ¸© TR ¹(2)D§T ·k (TR ) ¨ J ¸ VOUT,MHZ  ^VTH (TR )  J TJ  TR ` (5)© TR ¹
Fig. 9 shows an overview of the proposed IL estimation
method using MHZGD. When the measured VOUT,MHZ and TJ
are given, IL is estimated using Eq. (5). k(TR), VTH(TR), α, β,and γ are determined by the calibration method. Fig. 10 shows
the calibration method for finding the values of fiveparameters. For unknown IGBTs, five parameters are
determined by performing a five-point calibration from step 1
to step 5 only for the first one IGBT, and one parameter(VTH(TR)) is determined by performing a one-point calibrationfrom step 6 to step 7 for the second and subsequent IGBTs. In
Step 1, three VOUT,MHZ’s are measured at three different IL’s at
TJ = TR = 25 °C. In Step 2, k(TR), VTH(TR), and α aredetermined by the curve fitting [13] as shown in Fig. 11 (a).
In Step 3, two VOUT,MHZ’s are measured at two different IL’s at
TJ = 125 °C. In Step 4, k(TJ = 125 °C) and VTH(TJ = 125 °C)

IL

IG = 78 mA

10

(1)
D

VTH (TJ ) VTH (TR )  J TJ  TR

Fig. 7. Measured VOUT waveforms of two different IG’s at IL = 50
A and TJ = 25 °C. (a) Turn-on. (b) Turn-off.

0D

k (TJ )(b)

6

In this section, the proposed IL estimation method using
MHZGD is explained. Eq. (1) shows the IC model [10] basedon alpha-power law model of MOSFET [11], where k(TJ) is
the TJ-dependent constant, VTH(TJ) is the TJ-dependentthreshold voltage of IGBT, and α (1 < α < 2) is a constant.
Substituting IC = IL and VGE,INT = VOUT,MHZ into Eq. (1), Eq. (2)is obtained. Eq. (3) shows TJ dependence of k(TJ) [12], where
TR is the room temperature (25 °C) whose unit is absolutetemperature, k(TR) is k(TJ) at TJ = TR, and β (β > 0) is a constant.
Eq. (3) shows TJ dependence of VTH(TJ) [12], where VTH(TR)is VTH(TJ) at TJ = TR, and γ (γ > 0) is a constant. Substituting
Eqs. (3) and (4) into Eq. (2), Eq. (5) is obtained.

30 40 50 60 70
Load current (IL) [A]8090

5 parameters

J
D

(b)
Fig. 8. Measured IL dependence of VOUT,CONV and VOUT,MHZ of
two different IG’s at TJ = 25 °C. (a) Turn-on. (b) Turn-off.

1688

Output: Estimated IL

Fig. 9. Overview of proposed IL estimation method using MHZGD.

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)

Initial
calibration
for IGBT1

IL estimation
for second andsubsequent
IGBTs

Step 1

Measure VOUT,MHZ’s at 3 different IL’s at TJ=TR=25˚C

Step 2Derive k(TR), VTH(TR), and ࢻ by curve fitting (Fig. 11(a))

Step 3

Measure VOUT,MHZ’s at 2 different IL’s at TJ=125˚C

Step 4

Derive k(TJ=125˚C) and VTH(TJ=125˚C) (Fig. 11(b))

Step 5Derive ࢼ and ࢽ (Figs. 11(c) and (d))

Step 6

Measure one VOUT,MHZ at any IL at TJ=TR=25˚C

Step 7

Derive VTH(TR)

Fig. 10. Calibration method for finding values of five parameters.

103

103

TJ=125˚C

102

IL

^

`

k(TR ) VOUT,MHZ VTH (TR )Load current (IL) [A]Load current (IL) [A]

TJ=TR=25˚C
D

Slope= D

101

IL

102

k (TJ ) ^VOUT,MHZ  VTH (TJ )`D

101

Measured

Measured100
0.1

1VOUT,MHZ – VTH(TR) [V]
(a)

100
0.1

10

20

§T ·
k (TR ) ¨ J ¸© TR ¹

MeasuredE

VTH (TR )  J TJ  TR

Measured

Slope= - ߛ = -7.56[mV/K]

Slope= -ߚ = -1.48

101

25˚C

VTH (TJ )VTH(TJ) [V ]k (TJ )k(TJ) [A/V D]

10

(b)

102

100
200

1
VOUT,MHZ – VTH(TJ) [V]

10

25˚C

125˚C

300

125˚C

0
200

500
600
400
400
300
TJ [K]
TJ [K](c)(d)
Fig. 11. Example of determination of parameters. (a) Step 2 in Fig. 10. (b) Step 4. (c) and (d) Step 5.

are determined by the curve fitting as shown in Fig. 11 (b). In
Step 5, β and γ are determined by the curve fitting as shown in
Figs. 11 (c) and (d). This completes the five-point calibration
only for the first one IGBT. For the second and subsequent
IGBTs, the same k(TR), α, β, and γ as the first one IGBT areused, and the one-point calibration from step 6 to step 7 arerequired to determine VTH(TR) for each IGBT to account for
manufacturing variations between IGBTs. In Step 6, one
VOUT,MHZ is measured at any IL at TJ = TR = 25 °C. In Step 7,
VTH(TR) is determined by the curve fitting. Different from the500

model-based prediction which requires eight IL measurements[8], the proposed estimation requires only one IL measurement.
Table I shows the measurement conditions and thecalibrated parameters obtained by the calibration method
shown in Fig. 10. IGBT1 indicates the first one IGBT, and
IGBT2,3 show the second and third IGBTs. In IGBT1, the fiveparameters are calibrated, while the one parameter (VTH(TR))
is calibrated in IGBT2 and IGBT3. Fig. 12 shows themeasured and estimated IL dependence of VOUT,MHZ of IGBT1
at TJ = 25 °C to 125 °C in 10 °C increments. The estimated2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)

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TABLE I. MEASUREMENT CONDITIONS AND CALIBRATED PARAMETERS IN ONE-POINT CALIBRATION

Parameters

Measuredconditions(TJ, IL)

SampleCalibrated
parameters

VTH(TR) [V](25˚C, 5A),
(25˚C, 20A),(25˚C, 80A),(125˚C, 5A),
(125˚C, 80A)

IGBT1

VTH(TR), k(TR), DߛE
E

6.64

9.5

Turn-on
IGBT1
IG = 43 mA

VOUT, MHZ [V]

9.0
8.5
8.0
7.5
7.0
6.5

6.83

IGBT3

VTH(TR)

6.87

D

ߚ

ߛ [mV/K]

13.4

1.80

1.48

7.56

10.0
Turn-on
IG = 43 mA

9.5

25˚C
35˚C
45˚C
55˚C
65˚C
75˚C
85˚C
95˚C
105˚C
115˚C
125˚C
Measured & Estimated

9.0
25 ºC

8.5

Measured(IGBT1)
Measured(IGBT2)
Measured(IGBT3)
Estimated

7.5
7.0

20

6.5

0

10

20

30 40 50 60 70 80 90
Load current (IL) [A]
Fig. 14. Measured and estimated IL dependence of VOUT,MHZ of
IGBT1-3 at TJ = 25 °C, 75 °C, and 125 °C.
10Turn-on
IGBT1
IG = 43 mA

25˚C
35˚C
45˚C
55˚C
65˚C
75˚C
85˚C
95˚C
105˚C +5.2%
115˚C
125˚C

−4.6%
10

20 30 40 50 60 70
Load current (IL) [A]8090125 ºC
75 ºC

8.0

IL estimation error [%]

6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0

10

VTH(TR)

30 40 50 60 70 80 90
Load current (IL) [A]
Fig. 12. Measured and estimated IL dependence of VOUT,MHZ of
IGBT1 at TJ = 25 °C to 125 °C in 10 °C increments.

IL estimation error [%]

0

IGBT2

VOUT, MHZ [V](25˚C, 5A)

k(TR) [A/VD@

+7.7%
5

0

-5

-10
0

IG = 43 mA
IGBT1
IGBT2
IGBT3

25 ºC

75 ºC

125 ºC−7.0%

10

20 30 40 50 60 70
Load current (IL) [A]8090

Fig. 13. IL estimation error in Fig. 12.

Fig. 15. IL estimation error in Fig. 14.

curves are calculated using Eq. (5) and Table I. Fig. 13 shows
the IL estimation error in Fig. 12. IL estimation error in IGBT1
in the range of 5 A to 80 A and TJ = 25 °C to 125 °C is within+ 5.2 % / − 4.6 %, which supports that TJ dependence of IL is
reasonably expressed in Eq. (5) with β and γ. Fig. 14 shows
the measured and estimated IL dependence of VOUT,MHZ of
IGBT1 to IGBT3 at TJ = 25 °C, 75 °C, and 125 °C. Fig. 15
shows the IL estimation error in Fig. 14. Please note that IL
estimation errors at IL = 20 A in IGBT2 and IGBT3 are 0 %,because the one-point calibration is done at IL = 20 A. IL
estimation error of three IGBTs in the range of 5 A to 80 A at
TJ = 25 °C, 75 °C, and 125 °C is within + 7.7 % / − 7.0 %,which supports that the manufacturing variations between
IGBTs are reasonably expressed in Eq. (5) with different
VTH(TR) for each IGBT shown in Table I.

IV. DISCUSSION ON NUMBER OF CALIBRATION POINTSIn the previous section, the one-point calibration is applied
to IGBT2 and IGBT3, and IL estimation error is within + 7.7 %/ − 7.0 % as shown in Fig. 15. Increasing the number of points
in the calibration can be considered as a way to reduce the IL
estimation error. When the number of calibration points isincreased, however, the cost of the calibration for each IGBT
will increase. To find out if increasing the number of points inthe calibration would decrease the IL estimation error, therelationship between the number of points in the calibrationand the IL estimation error is investigated in this section. Table
II shows the measurement conditions and calibrated
parameters obtained by five-point, four-point, and two-pointcalibrations. In the five-point calibration, the five parameters(k(TR), VTH(TR), α, β, and γ) for each IGBT are determined by

1690

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)

TABLE II. MEASUREMENT CONDITIONS AND CALIBRATED PARAMETERS.

Measuredconditions(TJ, IL)(25˚C, 5A),
(25˚C, 20A),(25˚C, 80A),(125˚C, 5A),
(125˚C, 80A)

Parameters

SampleCalibrated
parameters

VTH(TR) [V]k(TR) [A/VD@Dߚߛ [mV/K]

IGBT1

VTH(TR), k(TR), DߛE
E

6.64

13.4

1.80

1.48

7.56

IGBT2

VTH(TR), k(TR), DߛE
E

6.86

14.3

1.74

1.37

7.07

IGBT3

VTH(TR), k(TR), DߛE
E

6.92

14.7

1.71

1.21

7.41

ߚ

ߛ [mV/K]

1.48

7.56

(a) Five-point calibration.

Measuredconditions(TJ, IL)

SampleCalibrated
parameters

VTH(TR) [V]k(TR) [A/VD@(25˚C, 5A),
(25˚C, 20A),(25˚C, 80A),(125˚C, 5A),
(125˚C, 80A)

IGBT1

VTH(TR), k(TR), DߛE
E

6.64

13.4

(25˚C, 5A),
(25˚C, 80A),(125˚C, 5A),
(125˚C, 80A)

Parameters

D

1.80
IGBT2

VTH(TR), k(TR), ߛE

6.82

13.1

1.42

7.18

IGBT3

VTH(TR), k(TR), ߛE

6.85

12.9

1.28

7.56

D

ߚ

ߛ [mV/K]

1.80

1.48

7.56

(b) Four-point calibration.

Parameters

Measuredconditions(TJ, IL)

SampleCalibrated
parameters

VTH(TR) [V]k(TR) [A/V D@(25˚C, 5A),
(25˚C, 20A),(25˚C, 80A),(125˚C, 5A),
(125˚C, 80A)

IGBT1

VTH(TR), k(TR), DߛE
E

6.64

13.4

(25˚C, 5A),
(25˚C, 80A)

IGBT2

VTH(TR), k(TR)

6.82

13.1

IGBT3

VTH(TR), k(TR)

6.85

12.9

(c) Two-point calibration.

the calibration method shown in Fig. 10. In the four-pointcalibration, the five parameters are calibrated in IGBT1, while
the four parameter (k(TR), VTH(TR), β, and γ) is calibrated in
IGBT2 and IGBT3. In the two-point calibration, the fiveparameters are calibrated in IGBT1, while the two parameter(k(TR) and VTH(TR)) is calibrated in IGBT2 and IGBT3.

glance for the error range of two-point calibration to be larger
than that of one-point calibration. The reason is that the twopoint calibration is done at IL = 5 A and 80 A as shown in Fig.
16 (c) and the one-point calibration is done at IL = 20 A as
shown in Fig. 15, and the IL estimation error range of the onepoint calibration is accidentally small in this case.

Fig. 16 shows the IL estimation error of three IGBTs at TJ= 25 °C, 75 °C, and 125 °C in five-point, four-point, and twopoint calibrations. Table III shows a summary of the IL
estimation error in four different calibration methods. Whenthe number of calibration points is increased from one to five,the range of the IL estimation error decreases from 14.7 % to11.1 %. The five-point calibration, however, requires fivemeasurements at TJ = 25 °C and 125 °C for each IGBT, which
is not practical, because the calibration cost is high. Therefore,in conclusion, the one-point calibration is recommended andproposed in this paper. In Table III, it is not reasonable at first

V. CONCLUSIONSThe proposed MHZGD, which can be integrated on DGDIC, estimated IL from VOUT,MHZ without depending on IG, andIL estimation errors of three IGBTs were within + 7.7 % / −7.0 % using the one-point calibration in the range of 5 A to80 A at 25 °C, 75 °C, and 125 °C. When the number ofcalibration points is increased from one to five, the IL
estimation error range decreases from 14.7 % to 11.1 %. The
one-point calibration, however, is recommended, because thecost of the five-point calibration at TJ = 25 °C and 125 °C foreach IGBT is excessive.

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)

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IL estimation error [%]

7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
0

ACKNOWLEGEMENT
IG = 43 mA
IGBT1
IGBT2
IGBT3

+5.7%

125 ºCREFERENCES
[1]

75 ºC

10

This work was partly supported by JST-Mirai Program,Grant Number JPMJMI20E1, Japan.

25 ºC −5.4%

20 30 40 50 60 70
Load current (IL) [A]8090

IL estimation error [%]

(a)

7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
0

IG = 43 mA
75 ºC

IGBT1
IGBT2
IGBT3

+5.2%

125 ºC

25 ºC
10

−6.6%

20 30 40 50 60 70
Load current (IL) [A]

80

90

(b)

IL estimation error [%]10
IG = 43 mA
IGBT1
IGBT2
IGBT3

+6.6%

5

125 ºC
0

75 ºC

25 ºC

-5

-10
0

−9.0%
10

20 30 40 50 60 70
Load current (IL) [A]

80

90

(c)
Fig. 16. IL estimation error of IGBT1-3 at TJ = 25 °C, 75 °C, and
125 °C in (a) five-point, (b) four-point, and (c) two-pointcalibrations.

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TABLE III. SUMMARY OF IL ESTIMATION ERROR IN FOUR DIFFERENTCALIBRATION METHODS

1692

IL estimation error

Calibration
methodMax

MinMax − Min

5-point

+5.7%

−5.4%

11.1%

4-point

+5.2%

−6.6%

11.8%

2-point

+6.6%

−9.0%

15.6%

1-point

+7.7%

−7.0%

14.7%

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia)