CN102856893B - Dynamic active clamping circuit and electronic equipment - Google Patents
Dynamic active clamping circuit and electronic equipment Download PDFInfo
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- CN102856893B CN102856893B CN201210355236.8A CN201210355236A CN102856893B CN 102856893 B CN102856893 B CN 102856893B CN 201210355236 A CN201210355236 A CN 201210355236A CN 102856893 B CN102856893 B CN 102856893B
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Abstract
An embodiment of the invention discloses a dynamic active clamping circuit and electronic equipment. The dynamic active clamping circuit comprises an active clamping circuit and a bypass circuit, wherein the active clamping circuit comprises transient voltage suppressors used for suppressing transient overvoltage between a drain electrode and a source electrode of an insulated gate bipolar transistor, and the bypass circuit is used for bypassing part of the transient voltage suppressors in the active clamping circuit according to drive signals. By the technical scheme in the embodiment, safer and more effective protection of operation of the insulated gate bipolar transistor is benefited.
Description
Technical Field
The invention relates to the technical field of circuits, in particular to a dynamic active clamping circuit and electronic equipment.
Background
Insulated Gate Bipolar Transistors (IGBTs) are important power switching devices, which have the advantages of both power mosfets and power transistors, such as easy driving, large capacitance, high switching frequency, and the like.
When the IGBT is turned off, the drop rate of the drain current is high, the main circuit has large stray inductance, large surge voltage can be generated between the drain electrode and the source electrode of the IGBT, and even the surge voltage exceeds the rated drain-source voltage of the IGBT to damage the IGBT.
At present, an active clamping circuit is mostly adopted to suppress the surge Voltage of the turn-off of the IGBT, and a proper breakdown value of a Transient Voltage Suppressor (TVS) needs to be designed in the active clamping circuit, so that the Transient Voltage Suppressor cannot protect the IGBT when the breakdown value is too high, and malfunction may occur when the breakdown value is too low. In some application occasions, the voltage fluctuation of a power grid is large, the bus voltage can be very high, or the bus voltage can be increased during load energy feedback, if the breakdown value of the set TVS diode is too low, the bus voltage can be higher than the voltage point of the active clamping action, the active clamping circuit can malfunction to cause the error conduction of the IGBT, the situation that the IGBTs of an upper bridge and the IGBT of a lower bridge are conducted simultaneously can occur, the IGBT can be exploded if not protected in time, and therefore great risk exists.
Disclosure of Invention
The embodiment of the invention provides a dynamic active clamping circuit and electronic equipment, aiming at protecting the work of an IGBT (insulated gate bipolar transistor) more safely and effectively.
An embodiment of the present invention provides a dynamic active clamping circuit, which may include:
an active clamping circuit and a bypass circuit;
the active clamping circuit comprises a transient suppression diode, a voltage limiting circuit and a voltage limiting circuit, wherein the transient suppression diode is used for suppressing transient overvoltage between a drain electrode and a source electrode of the insulated gate bipolar transistor;
the bypass circuit is used for bypassing part of transient suppression diodes in the active clamping circuit according to a driving signal.
Optionally, the bypass circuit includes: the circuit comprises a delay turn-off circuit, an isolation driving circuit and a switch circuit;
the isolation driving circuit is used for driving the switching circuit to work based on a driving signal;
the delay turn-off circuit is used for turning off the switch circuit in a delay manner based on the driving signal;
the switch circuit is used for bypassing part of transient suppression diodes in the active clamping circuit.
Optionally, the delay shutdown circuit includes: the circuit comprises a first diode, a first capacitor, a first resistor, a second resistor and a third resistor; the anode of the first diode is connected with the input end of a driving signal through the second resistor; the cathode of the first diode is connected with the input end of the driving signal through the first resistor, the cathode of the first diode is grounded through the first capacitor, and the first capacitor is connected with the third resistor in parallel;
or,
the delay turn-off circuit includes: the circuit comprises a first diode, a first capacitor, a first resistor, a second resistor and a third resistor; the anode of the first diode is connected with the input end of a driving signal; the cathode of the first diode is connected with the input end of the driving signal through the second resistor and the first resistor, the cathode of the first diode is grounded through the second resistor and the first capacitor, and the first capacitor is connected with the third resistor in parallel.
Optionally, the resistance value of the first resistor is 20-30 times that of the second resistor.
Optionally, the isolation driving circuit includes: an optical coupling isolation chip; the primary optocoupler negative pin of the optocoupler isolation chip is grounded; and a positive pin of a primary optocoupler of the optocoupler isolation chip is connected with the input end of a driving signal through the first resistor.
Optionally, the isolation driving circuit further includes: a second capacitor;
and the positive drive power supply pin and the negative drive power supply pin of the optical coupling isolation chip are connected through the second capacitor.
Optionally, the switching circuit includes: the fourth resistor, the fifth resistor and the first triode;
the base electrode of the first triode is connected with the driving output pin of the optical coupling isolation chip through the fourth resistor; an emitting electrode of the first triode is connected with a negative driving power pin of the optical coupling isolation chip; and the base electrode and the emitting electrode of the first triode are also connected through the fifth resistor.
Optionally, the active clamping circuit includes: the second diode, the second triode, the third triode, the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the first transient suppression diode and the second transient suppression diode;
the base electrode of the second triode is connected with the input end of the driving signal through the ninth resistor, the collector electrode of the second triode is grounded, and the emitter electrode of the second triode is connected with the grid electrode of the insulated gate bipolar transistor through the eighth resistor; the base electrode of the third triode is connected with the base electrode of the second triode, the collector electrode of the third triode is connected with the power supply voltage input end, and the emitter electrode of the third triode is connected with the emitter electrode of the second triode;
the cathode of the second diode is connected with the gate of the insulated gate bipolar transistor through the seventh resistor, the cathode of the second diode is also connected with the base of the second triode through the sixth resistor, and the anode of the second diode is connected with the anode of the first transient suppression diode; the anode of the second diode is also connected with the emitter of the first triode;
the cathode of the first transient suppression diode is connected with the anode of a second transient suppression diode, and the collector of the first triode is also connected with the cathode of the first transient suppression diode; and the cathode of the second transient suppression diode is connected with the drain electrode of the insulated gate bipolar transistor.
Optionally, a breakdown voltage of the first transient suppression diode is smaller than a breakdown voltage of the second transient suppression diode.
In another aspect, the embodiment of the present invention provides an electronic device, wherein the electronic device is disposed with a dynamic active clamping circuit as described in the above embodiment.
As can be seen from the above, the dynamic active clamping circuit provided in the embodiment of the present invention includes: an active clamping circuit and a bypass circuit; the bypass circuit is used for bypassing part of the transient suppression diode in the active clamping circuit according to the driving signal; the active clamping circuit is used for restraining transient overvoltage between a drain electrode and a source electrode of the insulated gate bipolar transistor. The threshold voltage of the active clamping circuit can be changed into dynamic state due to the introduction of the bypass circuit which bypasses part of the transient suppression diode in the active clamping circuit according to the driving signal. The action voltage of the active clamping circuit is determined by the breakdown value of the transient suppression diode, the bypass circuit can bypass part of the transient suppression diodes in the active clamping circuit, so that the action voltage of the active clamping circuit in the on and off states of the insulated gate bipolar transistor can be different, and if the action voltage of the active clamping circuit after the insulated gate bipolar transistor is switched on is lower than the peak voltage of the insulated gate bipolar transistor in the off state, the active clamping circuit can be ensured to play a role in switching off the insulated gate bipolar transistor under the condition of large current; in addition, because the bus voltage has certain fluctuation, when the insulated gate bipolar transistor is switched off, the voltage point of the active clamping action in the prior art is constant, and when the fluctuated bus voltage is higher than the voltage point of the active clamping action, the insulated gate bipolar transistor is possibly conducted by mistake; the bypass circuit is introduced to bypass part of transient suppression diodes in the active clamping circuit, so that active clamping action voltage points become dynamic, and if the insulated gate bipolar transistor is conducted, the bypass circuit bypasses part of transient suppression diodes in the active clamping circuit; the bypass function is closed after the insulated gate bipolar transistor is turned off for a period of time, the active clamping action voltage point is higher than the active clamping action voltage point when the insulated gate bipolar transistor is turned on after the bypass function is closed, the dynamic active clamping action voltage point is favorable for overcoming the fluctuation of bus voltage to a certain extent, and further the work of the insulated gate bipolar transistor is more safely and effectively protected.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.
FIG. 1 is a schematic diagram of a dynamic active clamping circuit according to a first embodiment of the present invention;
FIG. 2 is a diagram of a dynamic active clamping circuit according to a second embodiment of the present invention;
FIG. 3 is a diagram of a dynamic active clamping circuit according to a third embodiment of the present invention;
FIG. 4 is a diagram of a dynamic active clamping circuit according to a fourth embodiment of the present invention;
FIG. 5 is a schematic diagram of a dynamic active clamping circuit according to a fifth embodiment of the present invention;
fig. 6 is a schematic pin distribution diagram of an optical coupler isolator chip according to an embodiment of the present invention;
FIG. 7 is a diagram of a dynamic active clamping circuit according to a sixth embodiment of the present invention;
fig. 8 is a schematic diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a dynamic active clamping circuit and electronic equipment, aiming at protecting the work of an IGBT (insulated gate bipolar transistor) more safely and effectively.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The following examples are provided to explain the details of the present invention.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Referring to fig. 1, fig. 1 is a schematic diagram of a dynamic active clamping circuit according to a first embodiment of the invention. As shown in fig. 1, the dynamic active clamping circuit 100 may include: an active clamping circuit 10 and a bypass circuit 20; the bypass circuit 20 is used for bypassing part of the transient suppression diodes in the active clamping circuit 10 according to the driving signal; the active clamping circuit 10 is used to suppress transient overvoltages between the drain and source of the igbt 30. For example, the bypass circuit 20 may be used to bypass a portion of the transient suppression diode in the active clamping circuit 10 after the igbt 30 is turned on.
Referring to fig. 2, fig. 2 is a schematic diagram of a dynamic active clamping circuit according to a second embodiment of the invention. As shown in fig. 2, the bypass circuit 20 in the dynamic active clamping circuit 100 may include: a delay shutdown circuit 21, an isolation drive circuit 22 and a switch circuit 23.
Wherein, the isolation driving circuit 22 is used for driving the switching circuit 23 to work based on the driving signal.
And a delay turn-off circuit 21 for delay turning off the switching circuit 23 based on the driving signal.
And a switch circuit 23 for bypassing a portion of the transient suppression diode in the active clamping circuit 10.
Referring to fig. 3, fig. 3 is a schematic diagram of a dynamic active clamping circuit according to a third embodiment of the invention. As shown in fig. 3, the delay shutdown circuit 21 may also be disposed between the isolation drive circuit 22 and the switch circuit 23.
Referring to fig. 4, fig. 4 is a schematic diagram of a dynamic active clamping circuit according to a fourth embodiment of the invention. As shown in fig. 4, the delay shutdown circuit 21 may include:
a first diode D1,
A first capacitor C1,
A first resistor R1, a second resistor R2, and a third resistor R3.
The cathode of the first diode D1 is grounded through a first capacitor C1, the cathode of the first diode D1 is further connected to the input terminal P1 of the driving signal through a first resistor R1, the anode of the first diode D1 is connected to the input terminal P1 of the driving signal through a second resistor R2, and the first capacitor C1 is further connected in parallel to the third resistor R3.
In some embodiments of the present invention, the resistance of the first resistor R1 is greater than the resistance of the second resistor R2. For example, the resistance of the first resistor R1 is 20 to 30 times that of the second resistor R2, although the resistance of the first resistor R1 may be other times that of the second resistor R2, so as to achieve the required delay.
Referring to fig. 5, fig. 5 is a schematic diagram of a dynamic active clamping circuit according to a fifth embodiment of the present invention. As shown in fig. 5, the delay shutdown circuit 21 may include:
a first diode D1,
A first capacitor C1,
A first resistor R1, a second resistor R2 and a third resistor R3;
wherein, the anode of the first diode D1 is connected to the input terminal P1 of the driving signal; the cathode of the first diode D1 is connected to the input terminal P1 of the driving signal through a second resistor R2 and a first resistor R1, the cathode of the first diode D1 is also connected to the ground through a second resistor R2 and a first capacitor C1, and the first capacitor C1 is also connected in parallel with the third resistor R3.
As shown in fig. 4 or 5, the isolation drive circuit 22 may include an opto-isolator chip PC 1.
Referring to fig. 6, fig. 6 is a schematic pin distribution diagram of an optical coupler isolation chip PC1 according to an embodiment of the present invention. As shown in fig. 6, the pins of the optically coupled isolation chip PC1 may include: the driving circuit comprises a primary optocoupler negative pin CATHODE, a primary optocoupler positive pin ANODE, a positive driving power supply pin VCC, a negative driving power supply pin VEE and a driving output pin VO.
Referring to fig. 4 and 5, a primary optocoupler negative pin CATHODE of the optocoupler isolation chip PC1 is grounded; the primary optical coupling ANODE pin ANODE of the optical coupling isolation chip PC1 is connected with the input end P1 of the driving signal through a first resistor R1.
Referring to fig. 7, fig. 7 is a schematic diagram of a dynamic active clamping circuit according to a sixth embodiment of the invention. As shown in fig. 7, the isolation driving circuit 22 further includes: a second capacitance C2; the positive driving power supply pin VCC and the negative driving power supply pin VEE of the optical coupling isolation chip PC1 are connected through a second capacitor C2.
As shown in fig. 4, 5, or 7, the switching circuit 23 may include: a fourth resistor R4, a fifth resistor R5 and a first triode Q1.
The base electrode of the first triode Q1 is connected with the driving output pin VO of the optocoupler isolation chip PC1 through a fourth resistor R4; an emitter of the first triode Q1 is connected with a negative driving power supply pin VEE of the optocoupler isolation chip PC 1; the base and emitter of the first transistor Q1 are also connected through a fifth resistor R5.
It is to be understood that the circuit structures of the delay shutdown circuit 21, the isolation driving circuit 22 and the switching circuit 23 of the dynamic active clamping circuit shown in fig. 4, fig. 5 or fig. 7 are only examples, and some components thereof may be replaced or omitted. For example, the first transistor Q1 may be replaced by a transistor, such as a MOSFET, and the circuit structure after replacement will not be described herein. For example, the optical coupler isolation chip PC1 may be replaced by other chips or circuits with equivalent functions, and the circuit structure of the replacement optical coupler isolation chip PC1 is not described herein again, and other conversion manners are similar.
As shown in fig. 4, 5 or 7, the active clamping circuit 10 may include:
a second diode D2,
A second triode Q2, a third triode Q3,
A sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9,
A first transient suppression diode Z1 and a second transient suppression diode Z2.
The base electrode of the second triode Q2 is connected with the input end P1 of the driving signal through a ninth resistor R9, the collector electrode of the second triode Q2 is grounded, and the emitter electrode of the third triode Q3 is connected with the gate electrode of the insulated gate bipolar transistor 30 through an eighth resistor R8; the base of the third transistor Q3 is connected to the base of the second transistor Q2, the collector of the third transistor Q3 is connected to the supply voltage input Vcc, and the emitter of the third transistor Q3 is connected to the emitter of the second transistor Q2.
The cathode of the second diode D2 is connected to the gate of the igbt 30 through a seventh resistor R7, the cathode of the second diode D2 is also connected to the base of the second transistor Q2 through a sixth resistor R6, and the anode of the second diode D2 is connected to the anode of the first transient suppression diode Z1; the anode of the second diode D2 is also connected to the emitter of the first transistor Q1;
the cathode of the first transient suppression diode Z1 is connected with the anode of the second transient suppression diode Z2, and the collector of the first triode Q1 is also connected with the cathode of the first transient suppression diode Z1; the cathode of the second transient suppression diode Z2 is connected to the drain of the igbt 30.
In some embodiments of the present invention, the breakdown voltage of the first transient suppression diode Z1 is less than the breakdown voltage of the second transient suppression diode Z2. The difference between the breakdown voltage of the first transient suppression diode Z1 and the breakdown voltage of the second transient suppression diode Z2 can be set according to actual needs, for example, the breakdown voltage of the first transient suppression diode Z1 can be 1/6 to 1/3 of the breakdown voltage of the second transient suppression diode Z2. In practical applications, the first transient suppression diode Z1 may be 1 transient suppression diode, or may be formed by connecting a plurality of transient suppression diodes in series and/or in parallel in the same direction, so as to obtain the required breakdown voltage of the first transient suppression diode Z1; similarly, the second transient suppression diode Z2 may be 1 transient suppression diode, or may be formed by connecting multiple transient suppression diodes in series and/or parallel in the same direction to obtain the desired breakdown voltage of the second transient suppression diode Z2.
It is to be understood that the circuit structure of the active clamping circuit 10 in the dynamic active clamping circuit shown in fig. 4, fig. 5 or fig. 7 is only an example, and some components may be replaced or omitted. For example, the second transistor Q2 and/or the third transistor Q2 may be replaced by a field effect transistor, and the circuit structure after replacement is not described herein again, and other conversion manners are similar.
The operation of the dynamic active clamping circuit shown in fig. 4, 5 or 7 will be briefly described.
A driving signal (e.g., a Pulse Width Modulation (PWM) signal or other types of driving signals) is input from the driving signal input terminal P1, the igbt 30 is turned on when the driving signal is high, and the igbt 30 is turned off when the driving signal is low. In the active clamping circuit 10, the operation voltage value is determined by the reverse breakdown values of the first transient suppression diode Z1 and the second transient suppression diode Z2, the second diode D2 plays a role of unidirectional conduction to prevent current from flowing to the drain of the insulated gate bipolar transistor 30 when the gate of the insulated gate bipolar transistor 30 is at a high level, and the sixth resistor R6 and the seventh resistor R7 mainly play a role of current limiting. In the bypass circuit 20, the first resistor R1, the second resistor R2, and the third resistor R3 are current limiting resistors, and limit the current of the primary optocoupler ANODE pin ANODE. The first capacitor C1 is a filtering energy storage capacitor to enhance the anti-interference performance of the primary optocoupler. Meanwhile, the first resistor R1, the second resistor R2, the third resistor R3, the first diode D1 and the first capacitor C1 form a time-delay turn-off circuit. The optical coupling isolation driving chip PC1 plays roles in isolation and power amplification, the optical coupling isolation driving chip PC1 can play roles in isolating strong electricity and driving the first triode Q1, when the primary optical coupling is conducted, the output pin VO is driven to output a high driving level, and the first triode Q1 is conducted; when the primary optocoupler is not conducted, the output of the driving output pin VO is at a low level, and the first triode Q1 is turned off. The fourth resistor R4 is a gate driving resistor of the first transistor Q1, and the fifth resistor R5 is a gate charge-discharging resistor of the first transistor Q1.
When the igbt 30 is turned off and a surge voltage occurs, the second transient suppression diode Z2 is broken down and clamped, and at the same time, the second diode D2 is turned on. The second diode D2 is connected with two branch circuits, wherein, one branch circuit is directly connected with the grid electrode through the seventh resistor R7, TVS current flows through the grid electrode, the grid electrode voltage is increased, the turn-off process of the insulated gate bipolar transistor 30 is slowed down, and therefore surge voltage is restrained; the other branch is connected to the front stage side of the driving circuit through a sixth resistor R6, and the TVS current and the power consumption are reduced through the gain of the driving circuit.
When the driving signal is at a high level (at this time, the igbt 30 is turned on), the primary optocoupler in the optocoupler driving chip PC1 is turned on, and the driving output pin VO of the optocoupler driving chip PC1 outputs a high level, so that the first triode Q1 is turned on, the first transient suppression diode Z1 is bypassed (short-circuited), and the operating voltage of the active clamping circuit 10 is the reverse breakdown value of the second transient suppression diode Z2. When the driving signal is at a low level (at this time, the igbt 30 is turned off), after a delay period, the primary optocoupler in the optocoupler driving chip PC1 is turned off, and the VO pin of the driving output pin in the optocoupler driving chip PC1 outputs a low level, so that the first triode Q1 is turned off (at this time, the bypass function is disabled), the operating voltage of the active clamping circuit 10 is the reverse breakdown value of the first transient suppressor Z1 plus the second transient suppressor Z2, and the operating voltage at this time is greater than the operating voltage when the igbt 30 is turned on. Furthermore, if the first resistor R1 in the delay turn-off circuit 21 is larger than the second resistor R2, the charging time of the first C1 capacitor is shorter than the discharging time, so that the on time of the optocoupler is shorter than the off time, and the delay turn-off of the first triode Q1 can be further achieved.
The active clamping circuit is mainly used for acting when the insulated gate bipolar transistor is turned off under the condition of large current, and the active clamping circuit does not act after the insulated gate bipolar transistor is completely turned off and when the insulated gate bipolar transistor is turned on. In order to solve the problem of possible misoperation of the active clamping circuit, the threshold voltage of the active clamping circuit is designed to be dynamic in the embodiment of the invention. The action voltage of the active clamping circuit is determined by the breakdown value of the transient suppression diode, and the transient suppression diodes are connected in series and then connected between the grid and the drain of the insulated gate bipolar transistor, namely the action voltage is equal to the sum of the reverse breakdown values of the transient suppression diodes. In the embodiment of the invention, after the insulated gate bipolar transistor is conducted, a part of transient suppression diodes are bypassed (short-circuited) to reduce the operating voltage; after the insulated gate bipolar transistor is turned off, delaying a period of time, and canceling the bypass function of the transient suppression diode to increase the operating voltage. This is achieved by setting the active clamping voltage in the active clamping circuit to V1 after the igbt is turned on, and setting the active clamping circuit to V2 with V1 less than V2 with a delay after the igbt is turned off. Therefore, the active clamping circuit can be ensured to play a role in turning off the insulated gate bipolar transistor under the condition of large current, and the problems of misoperation of the active clamping circuit and mis-conduction of the insulated gate bipolar transistor caused by the fact that the bus voltage is higher than the active clamping action voltage point after the insulated gate bipolar transistor is turned off in the prior art can be effectively solved.
Referring to fig. 8, fig. 8 is a schematic view of an electronic device 200 according to an embodiment of the present invention.
The dynamic active clamping circuit 100 provided in the above embodiment is deployed in the electronic device 200 shown in fig. 8.
It can be understood that the specific structure of the dynamic active clamping circuit 100 in the electronic device 200 of the present embodiment may be the dynamic active clamping circuit 100 in the above embodiments, for example, the implementation manners refer to fig. 1 to 7, and details are not repeated here.
To sum up, the dynamic active clamping circuit provided by the embodiment of the present invention includes: an active clamping circuit and a bypass circuit; the bypass circuit is used for bypassing part of the transient suppression diode in the active clamping circuit according to the driving signal; the active clamping circuit is used for restraining transient overvoltage between a drain electrode and a source electrode of the insulated gate bipolar transistor. The threshold voltage of the active clamping circuit can be changed into dynamic state due to the introduction of the bypass circuit which bypasses part of the transient suppression diode in the active clamping circuit according to the driving signal. The action voltage of the active clamping circuit is determined by the breakdown value of the transient suppression diode, the bypass circuit can bypass part of the transient suppression diodes in the active clamping circuit, so that the action voltage of the active clamping circuit in the on and off states of the insulated gate bipolar transistor can be different, if the action voltage of the active clamping circuit after the insulated gate bipolar transistor is switched on is lower than the peak voltage when the insulated gate bipolar transistor is switched off, the active clamping circuit can be ensured to function when the insulated gate bipolar transistor is switched off under the condition of large current, in addition, because the bus voltage has certain volatility, when the insulated gate bipolar transistor is switched off, the voltage point of the active clamping action in the prior art is constant, and when the fluctuated bus voltage is higher than the active clamping action voltage point, the insulated gate bipolar transistor can be switched on by mistake; the bypass circuit is introduced to bypass part of transient suppression diodes in the active clamping circuit, so that active clamping action voltage points become dynamic, and if the insulated gate bipolar transistor is conducted, the bypass circuit bypasses part of transient suppression diodes in the active clamping circuit; the bypass function is closed after the insulated gate bipolar transistor is turned off for a period of time, the active clamping action voltage point is higher than the active clamping action voltage point when the insulated gate bipolar transistor is turned on after the bypass function is closed, the dynamic active clamping action voltage point is favorable for overcoming the fluctuation of bus voltage to a certain extent, and further the work of the insulated gate bipolar transistor is protected more safely and effectively.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The dynamic active clamping circuit and the electronic device provided by the embodiment of the present invention are described in detail above, and a specific example is applied in the present disclosure to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understand the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (8)
1. A dynamic active clamping circuit, comprising:
an active clamping circuit and a bypass circuit;
the active clamping circuit comprises a transient suppression diode, a voltage limiting circuit and a voltage limiting circuit, wherein the transient suppression diode is used for suppressing transient overvoltage between a drain electrode and a source electrode of the insulated gate bipolar transistor;
the bypass circuit is used for bypassing part of transient suppression diodes in the active clamping circuit according to a driving signal;
the bypass circuit includes: the circuit comprises a delay turn-off circuit, an isolation driving circuit and a switch circuit;
the isolation driving circuit is used for driving the switching circuit to work based on a driving signal;
the delay turn-off circuit is used for turning off the switch circuit in a delay manner based on the driving signal;
the switch circuit is used for bypassing part of transient suppression diodes in the active clamping circuit;
the delay turn-off circuit includes: the circuit comprises a first diode, a first capacitor, a first resistor, a second resistor and a third resistor; the anode of the first diode is connected with the input end of a driving signal through the second resistor; the cathode of the first diode is connected with the input end of the driving signal through the first resistor, the cathode of the first diode is grounded through the first capacitor, and the first capacitor is connected with the third resistor in parallel;
or,
the delay turn-off circuit includes: the circuit comprises a first diode, a first capacitor, a first resistor, a second resistor and a third resistor; the anode of the first diode is connected with the input end of a driving signal; the cathode of the first diode is connected with the input end of the driving signal through the second resistor and the first resistor, the cathode of the first diode is grounded through the second resistor and the first capacitor, and the first capacitor is connected with the third resistor in parallel;
the resistance value of the first resistor is larger than that of the second resistor.
2. The dynamic active clamping circuit of claim 1, wherein the first resistor has a resistance value 20-30 times that of the second resistor.
3. The dynamic active clamping circuit of claim 1 or 2,
the isolation drive circuit includes: an optical coupling isolation chip; the primary optocoupler negative pin of the optocoupler isolation chip is grounded; and a positive pin of a primary optocoupler of the optocoupler isolation chip is connected with the input end of a driving signal through the first resistor.
4. The dynamic active clamping circuit of claim 3,
the isolation drive circuit further comprises: a second capacitor;
and the positive drive power supply pin and the negative drive power supply pin of the optical coupling isolation chip are connected through the second capacitor.
5. The active clamping circuit of claim 3,
the switching circuit includes: the fourth resistor, the fifth resistor and the first triode;
the base electrode of the first triode is connected with the driving output pin of the optical coupling isolation chip through the fourth resistor; an emitting electrode of the first triode is connected with a negative driving power pin of the optical coupling isolation chip; and the base electrode and the emitting electrode of the first triode are also connected through the fifth resistor.
6. The dynamic active clamping circuit of claim 4,
the active clamping circuit includes: the second diode, the second triode, the third triode, the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the first transient suppression diode and the second transient suppression diode;
the base electrode of the second triode is connected with the input end of the driving signal through the ninth resistor, the collector electrode of the second triode is grounded, and the emitter electrode of the second triode is connected with the grid electrode of the insulated gate bipolar transistor through the eighth resistor; the base electrode of the third triode is connected with the base electrode of the second triode, the collector electrode of the third triode is connected with the power supply voltage input end, and the emitter electrode of the third triode is connected with the emitter electrode of the second triode;
the cathode of the second diode is connected with the gate of the insulated gate bipolar transistor through the seventh resistor, the cathode of the second diode is also connected with the base of the second triode through the sixth resistor, and the anode of the second diode is connected with the anode of the first transient suppression diode; the anode of the second diode is also connected with the emitter of the first triode;
the cathode of the first transient suppression diode is connected with the anode of a second transient suppression diode, and the collector of the first triode is also connected with the cathode of the first transient suppression diode; and the cathode of the second transient suppression diode is connected with the drain electrode of the insulated gate bipolar transistor.
7. The dynamic active clamping circuit of claim 6,
the breakdown voltage of the first transient suppression diode is less than the breakdown voltage of the second transient suppression diode.
8. An electronic device, wherein the dynamic active clamping circuit of any of claims 1 to 7 is disposed in the electronic device.
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| CN105406701A (en) * | 2015-12-28 | 2016-03-16 | 深圳市库马克新技术股份有限公司 | IGBT overvoltage protection circuit and method |
| CN107046361A (en) * | 2016-12-30 | 2017-08-15 | 江苏中科君芯科技有限公司 | IGBT dynamic active clamping protective circuits |
| CN106787635A (en) * | 2017-01-06 | 2017-05-31 | 四川埃姆克伺服科技有限公司 | A kind of active clamped protection circuit for IGBT controls |
| CN108631557B (en) | 2017-03-20 | 2020-03-10 | 台达电子企业管理（上海）有限公司 | Grid voltage control circuit of insulated gate bipolar transistor and control method thereof |
| CN111884546B (en) * | 2020-08-06 | 2022-06-17 | 武汉久同智能科技有限公司 | Low-voltage large-current alternating-current servo driving system |
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| CN101394082A (en) * | 2007-08-03 | 2009-03-25 | 塞米克朗电子有限及两合公司 | Active clamping switch for a high performance semiconductor switch |
| CN201533294U (en) * | 2009-10-20 | 2010-07-21 | 西安交通大学 | A two-stage active gate control circuit for a high-power IGBT |
| CN102522933A (en) * | 2011-11-29 | 2012-06-27 | 中国航天时代电子公司 | Drive circuit for direct-current motor |
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| DE19838389C1 (en) * | 1998-08-24 | 2000-03-09 | Siemens Ag | Method and device for controlling a switchable converter valve with the number of series connections two or greater |
| US8598921B2 (en) * | 2006-11-22 | 2013-12-03 | Ct-Concept Holding Gmbh | Control circuit and method for controlling a power semiconductor switch |
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| CN101394082A (en) * | 2007-08-03 | 2009-03-25 | 塞米克朗电子有限及两合公司 | Active clamping switch for a high performance semiconductor switch |
| CN201533294U (en) * | 2009-10-20 | 2010-07-21 | 西安交通大学 | A two-stage active gate control circuit for a high-power IGBT |
| CN102522933A (en) * | 2011-11-29 | 2012-06-27 | 中国航天时代电子公司 | Drive circuit for direct-current motor |
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