US 11,705,899 B2Granted

Serial IGBT voltage equalization method and system based on auxiliary voltage source

AssigneeWuhan University

InventorsYigang He, Lie Li, Liulu He, Chenyuan Wang

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Abstract

A serial IGBT voltage equalization method and system based on an auxiliary voltage source is disclosed. The method includes the following steps. (1) Detect a port dynamic voltage of each serial IGBT. (2) Perform dynamic overvoltage diagnosis respectively on the port dynamic voltage of each IGBT. (3) Supply emergency high level signal to the gate of the IGBT when there is dynamic overvoltage. (4) Stop supplying emergency high level signal to the gate of the IGBT, supply a constant voltage at the gate of the IGBT through the auxiliary voltage source. The invention provides a constant voltage through the auxiliary voltage source, prolongs the off time of the faulty IGBT, and turns off other IGBTs simultaneously, thereby achieving the purpose of serial IGBT voltage equalization.

Claims5

Dependent claims

A serial insulated gate bipolar transistor (IGBT) voltage equalization method based on an auxiliary voltage source, comprising the following steps:

(1) detecting a collector-emitter dynamic voltage between a collector and an emitter of each of a serial IGBT, wherein the serial IGBT comprises at least two IGBTs;
(2) performing a dynamic overvoltage diagnosis on the collector-emitter dynamic voltage of each of the serial IGBT;
(3) supplying an emergency high level signal to a gate of one of the serial IGBT when a dynamic overvoltage is detected;
(4) stopping supplying the emergency high level signal to the gate of the one of the serial IGBT, and supplying a constant voltage at the gate of the one of the serial IGBT through the auxiliary voltage source,
wherein the method for determining a constant voltage supplied by the auxiliary voltage source is:
setting a first detection voltage value Ua to be close to 0, recording a time when an overvoltage IGBT and a reference voltage of the overvoltage IGBT UCE reach the first detection voltage value, which are respectively recorded as t1 and t2, thereby obtaining an overvoltage reaction delay time;
Δtdoff1=t2−t1
setting a second detection voltage value Ub, recording a time when the overvoltage IGBT and the reference voltage of the overvoltage IGBT UCE reach the second detection voltage value, which are respectively recorded as t3 and t4;
predicting the entire voltage rise time through the first detection voltage value Ua and the second detection voltage value Ub, thereby obtaining a delay time generated due to a difference in voltage rise slope:
Δ
⁢
t
doff2
=
U
t
⁢
o
⁢
t
⁢
a
⁢
l
n
⁡
(
U
b
-
U
a
)
⁡
[
(
t
4
-
t
2
)
-
(
t
3
-
t
1
)
]
wherein Utotal is a total voltage of the serial IGBT, and n is the number of IGBTs connected in series;
wherein an amplitude of the constant voltage supplied by the auxiliary voltage source is calculated through the following equation:
Δ
⁢
U
=
U
o
⁢
n
[
exp
⁢
(
(
t
2
-
t
1
)
+
U
t
⁢
o
⁢
t
⁢
a
⁢
l
n
⁡
(
U
b
-
U
a
)
⁡
[
(
t
4
-
t
2
)
-
(
t
3
-
t
1
)
]
R
g
⁡
(
C
g
⁢
e
+
C
g
⁢
c
)
)
-
1
]
wherein Rg is a gate resistance of the overvoltage IGBT, Cge is a gate collector pole capacitance of the overvoltage IGBT, Cgc is a gate emitter pole capacitance of the overvoltage IGBT, Uon is a gate driving signal high level amplitude of the overvoltage IGBT.

126 more elements

A serial insulated gate bipolar transistor (IGBT) voltage equalization system based on an auxiliary voltage source, comprising:

a detection module configured to detect a collector-emitter dynamic voltage between a collector and an emitter of each of a serial IGBT, wherein the serial IGBT comprises at least two IGBTs;
a diagnostic module configured to perform a dynamic overvoltage diagnosis on the collector-emitter dynamic voltage of each of the serial IGBT;
a high level signal supplying module configured to supply an emergency high level signal to a gate of one of the serial IGBT when a dynamic overvoltage exists between the collect and the emitter of the one of the serial IGBT;
the auxiliary voltage source configured to supply a constant voltage to the gate of the one of the serial IGBT when the dynamic overvoltage exists between the collect and the emitter of one of the one of the serial IGBT,
wherein the method for determining a constant voltage supplied by the auxiliary voltage source is:
setting a first detection voltage value Ua to be close to 0, recording a time when an overvoltage IGBT and a reference collector-emitter voltage of the overvoltage IGBT UCE reach the first detection voltage value, which are respectively recorded as t1 and t2, thereby obtaining an overvoltage reaction delay time;
Δtdoff1=t2−t1
setting a second detection voltage value Ub, recording a time when the overvoltage IGBT and the reference collector-emitter voltage of the overvoltage IGBT UCE reach the second detection voltage value, which are respectively recorded as t3 and t4;
predicting the entire voltage rise time through the first detection voltage value Ua and the second detection voltage value Ub, thereby obtaining a delay time generated due to a difference in voltage rise slope:
Δ
⁢
t
doff
⁢
⁢
2
=
U
t
⁢
o
⁢
t
⁢
a
⁢
l
n
⁡
(
U
b
-
U
a
)
⁡
[
(
t
4
-
t
2
)
-
(
t
3
-
t
1
)
]
wherein Utotal is a total voltage of the serial IGBT, and n is the number of IGBTs connected in series;
wherein an amplitude of the constant voltage supplied by the auxiliary voltage source is calculated through the following equation:
Δ
⁢
U
=
U
o
⁢
n
[
exp
⁢
(
(
t
2
-
t
1
)
+
U
total
n
⁡
(
U
b
-
U
a
)
⁡
[
(
t
4
-
t
2
)
-
(
t
3
-
t
1
)
]
R
g
⁡
(
C
g
⁢
e
+
C
g
⁢
c
)
)
-
1
]
wherein Rg is a gate resistance of the overvoltage IGBT, Cge is a gate collector pole capacitance of the overvoltage IGBT, Cgc is a gate emitter pole capacitance of the overvoltage IGBT, Uon is a gate driving signal high level amplitude of the overvoltage IGBT.

121 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/709,939Filed 11 Dec 2019
Priority: CN 201910539291.420 Jun 2019
Published: US 2020/0403610 A124 Dec 2020
Granted: 18 Jul 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H03K 17/08126
By measures taken in the control circuit: in bipolar transitor switches
H03K 17/0828
By feedback from the output to the control circuit: in composite switches
G01R 31/261
For testing bipolar transistors: for measuring break-down voltage or punch through voltage therefor
H03K 17/107
Modifications for increasing the maximum permissible switched voltage: in composite switches