IGBT desaturation detection protection device of servo driver

Abstract

The utility model provides an IGBT desaturation detection protection device of a servo driver. The IGBT desaturation detection protection device comprises a first signal sampling unit, a second signal sampling unit, an H-bridge inverter circuit and an alarm unit. The first signal sampling unit is connected with a first collector voltage and a first grid signal of a first to-be-tested IGBT; the second signal sampling unit accesses a second collector voltage of a second to-be-tested IGBT and a second gate signal of the second to-be-tested IGBT. The output end of the first signal sampling unit is connected to the first input end of the H-bridge inverter circuit, the output end of the second signal sampling unit is connected to the second input end of the H-bridge inverter circuit, and the output end of the H-bridge inverter circuit is connected to the alarm module; the input end of the alarm module is also connected with a blocking signal and a protection signal; the alarm unit outputs an alarm signal. The H-bridge inverter circuit IGBT desaturation detection protection circuit adopts the design of discrete components, realizes H-bridge inverter circuit IGBT desaturation detection protection, and can reliably protect an insulated gate bipolar transistor.

Description

Technical Field

[0001] This utility model belongs to the field of transistor safety detection technology, and specifically relates to an IGBT desaturation detection and protection device for servo drivers. Background Technology

[0002] IGBT, or Insulated Gate Bipolar Transistor, is a composite, fully controllable, voltage-driven power semiconductor device composed of a bipolar transistor and an insulated gate field-effect transistor. In servo control systems, the desaturation detection and protection circuit of IGBTs traditionally uses a dedicated driver chip, which integrates IGBT driving and desaturation detection and protection. A low-power servo controller is a device used to control low-power servo motors; it typically possesses high control accuracy and fast response speed. Low-power servo motors are generally servo motors with power ranging from tens to hundreds of watts.

[0003] Some low-power servo controllers use only opto-isolated IGBT drivers to save costs, without employing IGBT desaturation detection and protection. However, IGBT driver and protection chips are expensive and have unpredictable supply cycles, affecting the production and cost of the servo controller. Without desaturation detection and protection circuitry, irreversible damage to the servo driver will occur in the event of a short circuit. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an IGBT desaturation detection and protection device for servo drivers. This can improve the reliability of low-power servo controllers and reduce their production costs.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An IGBT desaturation detection and protection device for a servo driver includes: a first signal sampling unit, a second signal sampling unit, an H-bridge inverter circuit, and an alarm unit;

[0007] The first signal sampling unit receives the first collector voltage and the first gate signal of the first IGBT under test; the second signal sampling unit receives the second collector voltage and the second gate signal of the second IGBT under test.

[0008] The output of the first signal sampling unit is connected to the first input of the H-bridge inverter circuit, the output of the second signal sampling unit is connected to the second input of the H-bridge inverter circuit, and the output of the H-bridge inverter circuit is connected to the alarm module. The input of the alarm module is also connected to a blocking signal and a protection signal. The alarm unit outputs an alarm signal.

[0009] Furthermore, the H-bridge inverter circuit includes: Zener diode D34, Zener diode D30, Zener diode D29 and Zener diode D28;

[0010] The anode of Zener diode D34 is connected to that of Zener diode D30; the anode of Zener diode D29 is connected to that of Zener diode D28; the cathode of Zener diode D34 is connected to that of Zener diode D29; and the cathode of Zener diode D30 is connected to that of Zener diode D28.

[0011] Furthermore, the first collector voltage of the first IGBT under test is connected to the cathode of diode D32 in the first sampling unit; the first gate signal of the first IGBT under test is connected to the anode of diode D32 through resistor R64, and the other path is grounded through capacitor C44.

[0012] The second input of the anode of diode D32 is connected to the positive input of the first comparator IC6B; the negative input of the first comparator IC6B is grounded through resistor R55 and capacitor C42; the first output of the first comparator IC6B is connected to the cathodes of Zener diode D28 and Zener diode D20 in the H-bridge inverter circuit.

[0013] Furthermore, the positive input terminal of the first comparator IC6B is connected to the output terminal of the first comparator IC6B in sequence through resistor R56 and diode D36.

[0014] Furthermore, the second output of the first comparator IC6B is connected to +12VC via resistor R51; the third output of the first comparator IC6B is connected to -12VC via capacitor C39.

[0015] Furthermore, the second collector voltage of the second IGBT under test is connected to the cathode of diode D35 in the second sampling unit; the second gate signal of the second IGBT under test is connected to the anode of diode D35 through resistor R54, and the other path is grounded through capacitor C43.

[0016] The second input of the anode of diode D35 is connected to the positive input of the second comparator IC6A; the negative input of the second comparator IC6A is grounded through capacitor C40 and connected to +12VC through resistor R63; the first output of the second comparator IC6A is connected to the cathodes of Zener diode D29 and Zener diode D34 in the H-bridge inverter circuit.

[0017] Furthermore, the positive input terminal of the second comparator IC6A is connected to the output terminal of the second comparator IC6A in sequence through resistor R62 and diode D31.

[0018] Furthermore, the second output of the second comparator IC6A is connected to +12VC via resistor R61; the third output of the second comparator IC6A is connected to -12VC via capacitor C41.

[0019] Furthermore, the blocking signal IGBT and the alarm signal output by the alarm unit are connected to the base of transistor Q16 after voltage division; the emitter of transistor Q16 is connected to -12VC; the collector of transistor Q16 is connected to optocoupler U1; and the optocoupler is also connected to alarm light LED1.

[0020] Furthermore, the optocoupler uses a P521 chip.

[0021] The effects described in the invention are merely those of the embodiments, and not all the effects of the invention. One of the above technical solutions has the following advantages or beneficial effects:

[0022] This invention proposes an IGBT desaturation detection and protection device for a servo driver, comprising: a first signal sampling unit, a second signal sampling unit, an H-bridge inverter circuit, and an alarm unit. The first signal sampling unit receives the first collector voltage and the first gate signal of a first IGBT under test. The second signal sampling unit receives the second collector voltage and the second gate signal of a second IGBT under test. The output of the first signal sampling unit is connected to the first input of the H-bridge inverter circuit, and the output of the second signal sampling unit is connected to the second input of the H-bridge inverter circuit. The output of the H-bridge inverter circuit is connected to an alarm module. The input of the alarm module also receives a blocking signal and a protection signal. The alarm unit outputs an alarm signal. This invention uses discrete components to design and implement IGBT desaturation detection and protection in an H-bridge inverter circuit. This invention determines whether the IGBT has entered a desaturation state by real-time monitoring of the voltage drop across the two lower IGBTs during turn-on. Once the IGBT enters a desaturation state, the IGBT gate drive signal is blocked, and an alarm signal is simultaneously sent to the control circuit, reliably protecting the insulated-gate bipolar transistor.

[0023] This invention achieves IGBT desaturation detection and protection with low hardware cost, and the protection sensitivity can be adjusted according to application conditions. Attached Figure Description

[0024] Figure 1 This is a circuit connection diagram of an IGBT desaturation detection and protection device for a servo driver according to Embodiment 1 of this utility model. Detailed Implementation

[0025] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and arrangements of specific examples are described below. Furthermore, reference numerals and / or letters may be repeated in different examples. This repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted to avoid unnecessarily limiting the present invention.

[0026] Example 1

[0027] Embodiment 1 of this utility model proposes an IGBT desaturation detection and protection device for a servo driver, which solves the technical problems existing in the IGBT desaturation detection in the prior art. Embodiment 1 of this utility model discloses an IGBT desaturation detection and protection device for a servo driver that simultaneously detects the voltage drop across the two lower IGBTs (IGBT1 and IGBT2) in the H-bridge inverter circuit of a low-power servo driver when they are turned on.

[0028] Figure 1 This is a circuit connection diagram of an IGBT desaturation detection and protection device for a servo driver according to Embodiment 1 of this utility model. The circuit diagram includes a first signal sampling unit, a second signal sampling unit, an H-bridge inverter circuit, and an alarm unit.

[0029] The first signal sampling unit receives the first collector voltage and the first gate signal of the first IGBT under test; the second signal sampling unit receives the second collector voltage and the second gate signal of the second IGBT under test.

[0030] The output of the first signal sampling unit is connected to the first input of the H-bridge inverter circuit, the output of the second signal sampling unit is connected to the second input of the H-bridge inverter circuit, and the output of the H-bridge inverter circuit is connected to the alarm module. The input of the alarm module is also connected to a blocking signal and a protection signal. The alarm unit outputs an alarm signal.

[0031] exist Figure 1 In the process, signal sampling includes: IGBT1 - collector voltage, IGBT2 - collector voltage, IGBT1 - gate signal, and IGBT2 - gate signal. Signal output includes: protection signal and IGBT lockout signal.

[0032] The H-bridge inverter circuit includes: Zener diode D34, Zener diode D30, Zener diode D29 and Zener diode D28;

[0033] The anode of Zener diode D34 is connected to that of Zener diode D30; the anode of Zener diode D29 is connected to that of Zener diode D28; the cathode of Zener diode D34 is connected to that of Zener diode D29; and the cathode of Zener diode D30 is connected to that of Zener diode D28.

[0034] The collector voltage of IGBT1 is connected to the cathode of diode D32 in the first sampling unit; the gate signal of IGBT1 is connected to the anode of diode D32 through resistor R64, and the other path is grounded through capacitor C44.

[0035] The second input of the anode of diode D32 is connected to the positive input of the first comparator IC6B; the negative input of the first comparator IC6B is grounded through resistor R55 and capacitor C42; the first output of the first comparator IC6B is connected to the cathodes of Zener diode D28 and Zener diode D20 in the H-bridge inverter circuit.

[0036] The positive input terminal of the first comparator IC6B is also connected to the output terminal of the first comparator IC6B in sequence through resistor R56 and diode D36.

[0037] The second output of the first comparator IC6B is connected to +12VC via resistor R51; the third output of the first comparator IC6B is connected to -12VC via capacitor C39.

[0038] The collector voltage of IGBT2 is connected to the cathode of diode D35 in the second sampling unit; the gate signal of IGBT2 is connected to the anode of diode D35 through resistor R54, and the other path is grounded through capacitor C43.

[0039] The second input of the anode of diode D35 is connected to the positive input of the second comparator IC6A; the negative input of the second comparator IC6A is grounded through capacitor C40 and connected to +12VC through resistor R63; the first output of the second comparator IC6A is connected to the cathodes of Zener diode D29 and Zener diode D34 in the H-bridge inverter circuit.

[0040] The positive input terminal of the second comparator IC6A is also connected to the output terminal of the second comparator IC6A in sequence through resistor R62 and diode D31.

[0041] The second output of the second comparator IC6A is connected to +12VC via resistor R61; the third output of the second comparator IC6A is connected to -12VC via capacitor C41.

[0042] The blocking signal from the IGBT and the alarm signal output from the alarm unit are divided and connected to the base of transistor Q16; the emitter of transistor Q16 is connected to -12VC; the collector of transistor Q16 is connected to optocoupler U1; the optocoupler is also connected to alarm light LED1. The optocoupler uses a P521 chip.

[0043] Embodiment 1 of this utility model proposes the following working process of an IGBT desaturation detection and protection device for a servo driver: When both IGBT1 and IGBT2 are working normally, the voltage at pin 2 of IC6A is divided by R63 and R55 to obtain a voltage of 8.5V. When the gate signal of IGBT2 is high, IGBT2 is turned on. Therefore, the collector signal of IGBT2 is low, pin 3 of IC6A is low, and pin 1 of IC6A is high. When the gate signal of IGBT2 is low, due to the presence of D35, pin 3 of IC6A is low, and pin 1 of IC6A is low.

[0044] The voltage at pin 6 of IC6B is divided by R63 and R55 to obtain a voltage of 8.5V. When the gate signal of IGBT1 is high, IGBT-1 is turned on. Therefore, the collector signal of IGBT1 is low, pin 5 of IC6B is low, and pin 1 of IC6A is high. When the gate signal of IGBT1 is low, due to the presence of D32, pin 5 of IC6B is low, and pin 7 of IC6B is low.

[0045] When the IGBT is working normally, pins 1 and 7 of IC6 output low level, so the IGBT blocking signal is low level, Q16 is cut off, and the protection signal is pulled up to high level through the fault alarm circuit.

[0046] The working process when either IGBT1 or IGBT2 is abnormal is as follows: When the gate of IGBT2 is at a high level, if IGBT2 fails, the collector voltage of IGBT2 will increase. When the voltage at pin 3 of IC6B is greater than or equal to 8.5V, pin 1 of IC6B outputs a high level, the IGBT blocking signal becomes high, and the gate signal of IGBT is blocked through the external protection circuit. Q16 is turned on, the protection signal becomes low, and is sent to the external alarm circuit. At the same time, LED1 lights up.

[0047] When the gate of IGBT1 is high, if IGBT1 malfunctions, the collector voltage of IGBT1 will increase. When the voltage at pin 5 of IC6A is greater than or equal to 8.5V, pin 7 of IC6A outputs a high level, the IGBT blocking signal becomes high, and the gate signal of the IGBT is blocked through the external protection circuit. Q16 turns on, the protection signal becomes low, and is sent to the external alarm circuit. At the same time, LED1 lights up.

[0048] The present invention provides an IGBT desaturation detection and protection device for a servo driver, which determines whether the IGBT has entered a desaturation state by real-time monitoring of the voltage drop of the two lower IGBT transistors when they are turned on. Once the IGBT enters a desaturation state, the IGBT gate drive signal is blocked, and an alarm signal is given to the control circuit, which can reliably protect the insulated gate bipolar transistor.

[0049] The present invention provides an IGBT desaturation detection and protection device for a servo driver, which achieves IGBT desaturation detection and protection with low hardware cost and allows for adjustment of protection sensitivity according to application conditions.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0051] While the specific embodiments of this utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this utility model. Those skilled in the art can make other modifications or variations based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. Various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of this utility model are still within the scope of protection of this utility model.

Claims

1. A servo driver IGBT desaturation detection and protection device, characterized in that, include: The circuit consists of a first signal sampling unit, a second signal sampling unit, an H-bridge inverter circuit, and an alarm unit. The first signal sampling unit receives the first collector voltage and the first gate signal of the first IGBT under test; the second signal sampling unit receives the second collector voltage and the second gate signal of the second IGBT under test. The output of the first signal sampling unit is connected to the first input of the H-bridge inverter circuit, the output of the second signal sampling unit is connected to the second input of the H-bridge inverter circuit, and the output of the H-bridge inverter circuit is connected to the alarm module. The input of the alarm module is also connected to a blocking signal and a protection signal. The alarm unit outputs an alarm signal.

2. The IGBT desaturation detection and protection device for a servo driver according to claim 1, characterized in that, The H-bridge inverter circuit includes: Zener diode D34, Zener diode D30, Zener diode D29 and Zener diode D28; The anode of Zener diode D34 is connected to that of Zener diode D30; the anode of Zener diode D29 is connected to that of Zener diode D28; the cathode of Zener diode D34 is connected to that of Zener diode D29; and the cathode of Zener diode D30 is connected to that of Zener diode D28.

3. The IGBT desaturation detection and protection device for a servo driver according to claim 1, characterized in that, The first collector voltage of the first IGBT under test is connected to the cathode of diode D32 in the first sampling unit; the first gate signal of the first IGBT under test is connected to the anode of diode D32 through resistor R64, and the other path is grounded through capacitor C44. The second input of the anode of diode D32 is connected to the positive input of the first comparator IC6B; the negative input of the first comparator IC6B is grounded through resistor R55 and capacitor C42; the first output of the first comparator IC6B is connected to the cathodes of Zener diode D28 and Zener diode D20 in the H-bridge inverter circuit.

4. The IGBT desaturation detection and protection device for a servo driver according to claim 3, characterized in that, The positive input terminal of the first comparator IC6B is also connected to the output terminal of the first comparator IC6B in sequence through resistor R56 and diode D36.

5. The IGBT desaturation detection and protection device for a servo driver according to claim 3, characterized in that, The second output of the first comparator IC6B is connected to +12VC through resistor R51; the third output of the first comparator IC6B is connected to -12VC through capacitor C39.

6. The IGBT desaturation detection and protection device for a servo driver according to claim 1, characterized in that, The second collector voltage of the second IGBT under test is connected to the cathode of diode D35 in the second sampling unit; the second gate signal of the second IGBT under test is connected to the anode of diode D35 through resistor R54, and the other path is grounded through capacitor C43. The second input of the anode of diode D35 is connected to the positive input of the second comparator IC6A; the negative input of the second comparator IC6A is grounded through capacitor C40 and connected to +12VC through resistor R63; the first output of the second comparator IC6A is connected to the cathodes of Zener diode D29 and Zener diode D34 in the H-bridge inverter circuit.

7. The IGBT desaturation detection and protection device for a servo driver according to claim 6, characterized in that, The positive input terminal of the second comparator IC6A is also connected to the output terminal of the second comparator IC6A in sequence through resistor R62 and diode D31.

8. The IGBT desaturation detection and protection device for a servo driver according to claim 6, characterized in that, The second output of the second comparator IC6A is connected to +12VC via resistor R61; the third output of the second comparator IC6A is connected to -12VC via capacitor C41.

9. The IGBT desaturation detection and protection device for a servo driver according to claim 1, characterized in that, The blocking signal IGBT and the alarm signal output by the alarm unit are connected to the base of transistor Q16 after voltage division; the emitter of transistor Q16 is connected to -12VC; the collector of transistor Q16 is connected to optocoupler U1; the optocoupler is also connected to alarm light LED1.

10. The IGBT desaturation detection and protection device for a servo driver according to claim 9, characterized in that, The optocoupler uses a P521 chip.

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