Driving protection circuit
By employing voltage limiting and control circuits in the active power filter to prevent IGBT module mis-current, the problem of IGBT damage is solved, the complexity and cost of circuit design are reduced, and the reliability and safety of the circuit are achieved.
Patent Information
- Application Number
- CN202520194434.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2026-02-27
- Estimated Expiration
- 2035-02-07
AI Technical Summary
In existing active power filters, IGBT modules are easily damaged by parasitic conduction caused by Miller capacitance, and negative voltage drive increases the complexity and cost of circuit design, while Miller clamping effect is poor.
The first and second voltage limiting circuits limit the voltage when the voltage of the switching unit exceeds the threshold. Combined with the control circuit, the voltage limiting circuit is reliably controlled to turn on and off, avoiding IGBT mis-turn-on and reducing design costs.
It effectively prevents IGBT damage, reduces circuit design complexity and cost, eliminates the need for negative voltage drive, and improves circuit reliability and safety.
Smart Images
Figure CN223957294U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] Embodiments of the present disclosure relate to the field of electrical equipment, and more particularly to a drive protection circuit. BACKGROUND
[0002] An active power filter is a new type of special equipment for power harmonic control made on the basis of digital signal processing technology of high-speed digital signal processor (DSP). The active power filter is usually composed of two main parts, i.e. an instruction current operation circuit and a compensation current generation circuit. The instruction current operation circuit monitors the current in the line in real time, converts the analog current signal into a digital signal, sends the digital signal into the DSP for processing, separates the harmonic from the fundamental wave, and sends out a driving pulse in the form of a pulse width modulation (PWM) signal to the compensation current generation circuit, so as to drive an insulated gate bipolar transistor (IGBT) module. SUMMARY
[0003] In a first aspect of the present disclosure, a drive protection circuit is provided, comprising: a first switch unit and a second switch unit, a first end of the first switch unit being connected to a predetermined circuit terminal, a second end of the first switch unit being connected to the second switch unit; a first voltage limiting circuit and a second voltage limiting circuit, a first end of the first voltage limiting circuit being connected to the second end of the first switch unit, a second end of the first voltage limiting circuit being connected to a first ground and a first end of the second switch unit, a first end of the second voltage limiting circuit being connected to a control end of the second switch unit, a second end of the second voltage limiting circuit being connected to a second ground and a second end of the second switch unit, the second voltage limiting circuit being capable of limiting a voltage value of a first voltage to a predetermined threshold value in a case where the voltage value of the first voltage between the control end of the second switch unit and the second end of the second switch unit exceeds the predetermined threshold value; and a first control circuit and a second control circuit, a first end of the first control circuit being connected to a first power supply, a second end of the first control circuit being connected to the first ground, an output end of the first control circuit being connected to the first voltage limiting circuit, a first end of the second control circuit being connected to a second power supply, a second end of the second control circuit being connected to the second ground, an output end of the second control circuit being connected to the second voltage limiting circuit, the first control circuit and the second control circuit being capable of respectively controlling the first voltage limiting circuit and the second voltage limiting circuit to be turned on and turned off.
[0004] In embodiments according to the present disclosure, by adopting the first voltage limiting circuit, the voltage can be limited to the predetermined threshold value in a case where the voltage at the second switch unit exceeds the predetermined threshold value, by adopting the second voltage limiting circuit, the voltage can be limited to the predetermined threshold value in a case where the voltage at the first switch unit exceeds the predetermined threshold value, and by adopting the first control circuit and the second control circuit, the first voltage limiting circuit and the second voltage limiting circuit can be reliably controlled to be turned on and turned off, respectively.
[0005] In some embodiments, the first switch unit comprises: a first switch device, a first electrode of the first switch device is connected to the predetermined circuit terminal, a second electrode of the first switch device is connected to the first end of the first voltage limiting circuit; a first capacitor, a first end of the first capacitor is connected to the first electrode of the first switch device, a second end of the first capacitor is connected to the control end of the first switch device; and a first diode, a cathode of the first diode is connected to the first electrode of the first switch device, an anode of the first diode is connected to the second electrode of the first switch device.
[0006] In some embodiments, the second switch unit comprises: a second switch device, a first electrode of the second switch device is connected to the second end of the first voltage limiting circuit, a second electrode of the second switch device is connected to the second end of the second voltage limiting circuit, a control end of the second switch device is connected to the first end of the second voltage limiting circuit; a second capacitor, a first end of the second capacitor is connected to the first electrode of the second switch device, a second end of the second capacitor is connected to the control end of the second switch device; and a second diode, a cathode of the second diode is connected to the first electrode of the second switch device, an anode of the second diode is connected to the second electrode of the second switch device.
[0007] In some embodiments, the first voltage limiting circuit comprises: a first triode, an emitter of the first triode is connected to the second end of the first switch unit; a first resistor, a first end of the first resistor is connected to the emitter of the first triode, a second end of the first resistor is connected to the base of the first triode; and a second resistor, a first end of the second resistor is connected to the collector of the first triode, a second end of the second resistor is connected to the first ground.
[0008] In some embodiments, the first voltage limiting circuit further comprises a third diode, a cathode of the third diode is connected to the emitter of the first triode, an anode of the third diode is connected to the collector of the first triode.
[0009] In some embodiments, the second voltage limiting circuit comprises: a second triode, an emitter of the second triode is connected to the control end of the second switch unit; a third resistor, a first end of the third resistor is connected to the emitter of the second triode, a second end of the third resistor is connected to the base of the second triode; and a fourth resistor, a first end of the fourth resistor is connected to the collector of the second triode, a second end of the fourth resistor is connected to the second ground.
[0010] In some embodiments, the second voltage limiting circuit further comprises a fourth diode, a cathode of the fourth diode is connected to the emitter of the second triode, an anode of the fourth diode is connected to the collector of the second triode.
[0011] In some embodiments, the first control circuit includes: a first MOS tube, a drain of the first MOS tube being connected to the first power supply; a second MOS tube, a drain of the second MOS tube being connected to a source of the first MOS tube, a source of the second MOS tube being connected to the first ground; and a first driving unit, the first driving unit being connected to gates of the first MOS tube and the second MOS tube.
[0012] In some embodiments, the second control circuit includes: a third MOS tube, a drain of the third MOS tube being connected to the second power supply; a fourth MOS tube, a drain of the fourth MOS tube being connected to a source of the third MOS tube, a source of the fourth MOS tube being connected to the second ground; and a second driving unit, the second driving unit being connected to gates of the third MOS tube and the fourth MOS tube.
[0013] It should be understood that the contents described in this content part are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they used to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS
[0014] The above and other features, advantages, and aspects of embodiments of the present disclosure will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
[0015] Figure 1 A circuit schematic diagram of a driving protection circuit according to some embodiments of the present disclosure is shown; and
[0016] Figure 2 A voltage signal change diagram of a control end of a second switching device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION
[0017] Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.
[0018] The term "comprising" and variations thereof as used herein are intended to cover a non-exclusive inclusion, i.e., "including, but not limited to". Unless specifically stated, the term "or" means "and / or". The term "based on" means "based, at least in part, on". The terms "one example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. can refer to different or same objects.
[0019] As described above, the active power filter is a new type of power harmonic control special device made based on the digital signal processing technology of DSP. The active power filter is usually composed of two main parts, namely, an instruction current operation circuit and a compensation current generation circuit. The instruction current operation circuit monitors the current in the line in real time, converts the analog current signal into a digital signal, sends the signal into the DSP for processing, separates the harmonic from the fundamental wave, and sends out a driving pulse in the form of a PWM signal to the compensation current generation circuit, so as to drive the IGBT module.
[0020] In the daily work of the IGBT module, the parasitic conduction caused by the Miller capacitor can cause the upper and lower bridges in the bridge IGBT circuit to be directly connected, which can cause the IGBT to overcurrent and be damaged, and even cause the problem of tube explosion in severe cases. This is a potential danger for the IGBT and even the entire active power filter.
[0021] In order to prevent the IGBT from being turned on due to the parasitic effect, a negative voltage drive is usually applied to the bridge IGBT circuit and a drive chip with a Miller clamp is selected. However, the negative voltage drive increases the complexity of the power supply design and the cost of the circuit design. The drive chip with the Miller clamp function is often limited by the length of the circuit board wiring, and the effect of the Miller clamp is not good.
[0022] Therefore, the embodiment of the present disclosure provides a driving protection circuit. In the driving protection circuit, the first voltage limiting circuit can limit the voltage to a predetermined threshold value when the voltage at the second switching unit exceeds the predetermined threshold value. The second voltage limiting circuit can limit the voltage to a predetermined threshold value when the voltage at the first switching unit exceeds the predetermined threshold value. The first control circuit and the second control circuit can reliably control the first voltage limiting circuit and the second voltage limiting circuit to turn on and off, respectively. Avoiding damage caused by parasitic conduction of the switching device, and without the need to increase the negative voltage drive, the design cost of the circuit is reduced. In the following, the principle of the present disclosure will be described in detail in combination with Figure 1 and Figure 2 The principle of the present disclosure will be described in detail.
[0023] Figure 1 The circuit schematic diagram of the driving protection circuit 100 according to some embodiments of the present disclosure is shown. As shown in FIG. 1, the driving protection circuit 100 includes a first voltage limiting circuit 101, a second voltage limiting circuit 102, a first control circuit 103, a second control circuit 104, a first switching unit 105, a second switching unit 106, a first IGBT module 107, and a second IGBT module 108. Figure 1As shown, the drive protection circuit 100 generally includes a first switch unit 11 and a second switch unit 12, a first voltage limiting circuit 31 and a second voltage limiting circuit 32, and a first control circuit 41 and a second control circuit 42. A first terminal of the first switch unit 11 is connected to the predetermined circuit terminal 20. A second terminal of the first switch unit 11 is connected to the second switch unit 12. A first terminal of the first voltage limiting circuit 31 is connected to the second terminal of the first switch unit 11. A second terminal of the first voltage limiting circuit 31 is connected to the first ground GND1 and a first terminal of the second switch unit 12. A first terminal of the second voltage limiting circuit 32 is connected to a control terminal of the second switch unit 12. A second terminal of the second voltage limiting circuit 32 is connected to the second ground GND2 and a second terminal of the second switch unit 12. The second voltage limiting circuit 32 is capable of limiting a voltage magnitude of a first voltage between the control terminal of the second switch unit 12 and the second terminal of the second switch unit 12 to a predetermined threshold value, in a case where the voltage magnitude of the first voltage exceeds the predetermined threshold value. A first terminal of the first control circuit 41 is connected to a first power supply 51. A second terminal of the first control circuit 41 is connected to the first ground GND1. An output terminal of the first control circuit 41 is connected to the first voltage limiting circuit 31. A first terminal of the second control circuit 42 is connected to a second power supply 52. A second terminal of the second control circuit 42 is connected to the second ground GND2. An output terminal of the second control circuit 42 is connected to the second voltage limiting circuit 32. The first control circuit 41 and the second control circuit 42 are respectively capable of controlling the first voltage limiting circuit 31 and the second voltage limiting circuit 32 to be turned on and turned off.
[0024] In some embodiments, the first switch unit 11 includes a first switching device 111, a first capacitor 112, and a first diode 113. A first electrode of the first switching device 111 is connected to the predetermined circuit terminal 20. A second electrode of the first switching device 111 is connected to the first terminal of the first voltage limiting circuit 31. A first terminal of the first capacitor 112 is connected to the first electrode of the first switching device 111. A second terminal of the first capacitor 112 is connected to a control terminal of the first switching device 111. A cathode of the first diode 113 is connected to the first electrode of the first switching device 111, and an anode of the first diode 113 is connected to the second electrode of the first switching device 111.
[0025] In some embodiments, the second switch unit 12 includes a second switching device 121, a second capacitor 122, and a second diode 123. The first electrode of the second switching device 121 is connected to the second end of the first voltage limiting circuit 31. The second electrode of the second switching device 121 is connected to the second end of the second voltage limiting circuit 32. The control end of the second switching device 121 is connected to the first end of the second voltage limiting circuit 32. The first end of the second capacitor 122 is connected to the first electrode of the second switching device 121. The second end of the second capacitor 122 is connected to the control end of the second switching device 121. The cathode of the second diode 123 is connected to the first electrode of the second switching device 121. The anode of the second diode 123 is connected to the second electrode of the second switching device 121.
[0026] In some embodiments, the first switching device 111 and the second switching device 121 can be IGBTs. In the case where the first switching device 111 and the second switching device 121 are IGBTs, the first electrode is the collector, the second electrode is the emitter, and the control end is the gate. In the following, the principles of the present disclosure will be described taking IGBTs as examples of the first switching device 111 and the second switching device 121. However, it should be understood that the first switching device 111 and the second switching device 121 can also be of other types, and the embodiments of the present disclosure do not limit thereto.
[0027] In some embodiments, the first switching device 111 and the second switching device 121 are connected in series, with the emitter of the first switching device 111 connected to the collector of the second switching device 121. In the case where the potential at the predetermined circuit terminal 20 is U d , the potential at the node between the first switching device 111 and the second switching device 121 is U d / 2. In the case where the first switching device 111 is turned on, the voltage variation rate at the node is U d / (2*t on ), t on being the time for which the first switching device 111 is turned on. The voltage variation at the node will cause the second capacitor 122 to generate a current I c =C*U d / (2*t on ), C being the capacitance of the second capacitor 122.
[0028] In some embodiments, the first voltage limiting circuit 31 comprises a first transistor 311, a first resistor 312, and a second resistor 313. The emitter of the first transistor 311 is connected to the second end of the first switch unit 11. The first end of the first resistor 312 is connected to the emitter of the first transistor 311, and the second end of the first resistor 312 is connected to the base of the first transistor 311. The first end of the second resistor 313 is connected to the collector of the first transistor 311. The second end of the second resistor 313 is connected to the first ground.
[0029] In some embodiments, the second voltage limiting circuit 32 comprises a second transistor 321, a third resistor 322, and a fourth resistor 323. The emitter of the second transistor 321 is connected to the control end of the second switch unit 12. The first end of the third resistor 322 is connected to the emitter of the second transistor 321, and the second end of the third resistor 322 is connected to the base of the second transistor 321. The first end of the fourth resistor 323 is connected to the collector of the second transistor 321. The second end of the fourth resistor 323 is connected to the second ground.
[0030] In some embodiments, the current I c generated at the second capacitor 122 flows through the fourth resistor 323, a voltage drop V = R*I c can be generated across the fourth resistor 323, where R is the resistance of the fourth resistor 323. When the voltage difference between the emitter and the base of the second transistor 321 exceeds a predetermined threshold value, the second transistor 321 is turned on. At this time, the voltage at the gate of the second switch device 121 is quickly discharged to the emitter of the second switch device 121 through the second transistor 321 and the fourth resistor 323, so that the voltage between the gate and the emitter of the second switch device 121 is less than the turn-on threshold voltage, thereby preventing the second switch device 121 from being mistakenly turned on. In addition, the fourth resistor 323 can provide current limiting protection for the second transistor 321. It should be understood that other types of switch devices that can be conceived by those of ordinary skill in the art based on the teachings given in the present disclosure can achieve the above functions, and these implementations all fall within the scope of the present disclosure.
[0031] The above process describes the case of preventing the second switch device 121 from being mistakenly turned on when the first switch device 111 is turned on. Conversely, the case of preventing the first switch device 111 from being mistakenly turned on when the second switch device 121 is turned on is the same as the principle of the above process, which will not be described here.
[0032] In some embodiments, the first voltage limiting circuit 31 can further include a third diode 314, and the second voltage limiting circuit 32 can further include a fourth diode 324. The cathode of the third diode 314 is connected to the emitter of the first triode 311, and the anode of the third diode 314 is connected to the collector of the first triode 311. The cathode of the fourth diode 324 is connected to the emitter of the second triode 321. The anode of the fourth diode 324 is connected to the collector of the second triode 321. By employing the third diode 314 and the fourth diode 324, respectively, the voltage at the gate of the first switch device 111 and the second switch device 121 can be prevented from being too low to cause the gate to be broken down by negative voltage. In this way, the negative voltage that the first switch device 111 and the second switch device 121 can withstand can be limited to a safe level, without the need for an additional negative voltage power supply, thereby reducing the design complexity and design cost of the circuit.
[0033] Figure 2 A voltage signal variation diagram of the control end of the second switch device 121 according to some embodiments of the present disclosure is shown. In some embodiments, as shown in Figure 2 with the first switch device 111 turned on, the second voltage limiting circuit 32 can limit both the positive voltage and the negative voltage at the second switch device 121 to a lower level, thereby greatly reducing the risk of the second switch device 121 being mistakenly turned on and damaged.
[0034] Referring back to Figure 1 In some embodiments, the first control circuit 41 includes a first MOS tube 511, a second MOS tube 512, and a first driving unit 510. The drain of the first MOS tube 511 is connected to the first power supply 51. The drain of the second MOS tube 512 is connected to the source of the first MOS tube 511. The source of the second MOS tube 512 is connected to the first ground. The first driving unit 510 is connected to the gates of the first MOS tube 511 and the second MOS tube 512.
[0035] In some embodiments, the second control circuit 42 includes a third MOS tube 521, a fourth MOS tube 522, and a second driving unit 520. The drain of the third MOS tube 521 is connected to the second power supply 52. The drain of the fourth MOS tube 522 is connected to the source of the third MOS tube 521. The source of the fourth MOS tube 522 is connected to the second ground. The second driving unit 520 is connected to the gates of the third MOS tube 521 and the fourth MOS tube 522.
[0036] In some embodiments, the first driving unit 510 and the second driving unit 520 can employ a driving chip to reliably control the on and off of the plurality of MOS tubes. Due to the limiting effect of the first voltage limiting circuit 31 and the second voltage limiting circuit 32 on the positive and negative voltages of the first switching device 111 and the second switching device 121, the driving chip can not need to be provided with a Miller clamp function, further reducing the circuit cost. It should be understood that other types of driving units that can be conceived by those of ordinary skill in the art based on the teachings given in the present disclosure can implement the above functions, and all such implementations fall within the scope of the present disclosure.
[0037] The above has described various embodiments of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.
Claims
1. A drive protection circuit (100), characterized in that comprises: a first switching unit (11) and a second switching unit (12), a first end of the first switching unit (11) being connected to a predetermined circuit terminal (20), a second end of the first switching unit (11) being connected to the second switching unit (12); a first voltage limiting circuit (31) and a second voltage limiting circuit (32), a first end of the first voltage limiting circuit (31) being connected to the second end of the first switching unit (11), a second end of the first voltage limiting circuit (31) being connected to a first ground and a first end of the second switching unit (12), a first end of the second voltage limiting circuit (32) being connected to a control end of the second switching unit (12), a second end of the second voltage limiting circuit (32) being connected to a second ground and a second end of the second switching unit (12), the second voltage limiting circuit (32) being capable of limiting a voltage magnitude of a first voltage between the control end of the second switching unit (12) and the second end of the second switching unit (12) to a predetermined threshold value in a case where the voltage magnitude of the first voltage exceeds the predetermined threshold value; and a first control circuit (41) and a second control circuit (42), a first end of the first control circuit (41) being connected to a first power supply (51), a second end of the first control circuit (41) being connected to the first ground, an output end of the first control circuit (41) being connected to the first voltage limiting circuit (31), a first end of the second control circuit (42) being connected to a second power supply (52), a second end of the second control circuit (42) being connected to the second ground, an output end of the second control circuit (42) being connected to the second voltage limiting circuit (32), the first control circuit (41) and the second control circuit (42) being capable of controlling the first voltage limiting circuit (31) and the second voltage limiting circuit (32) to be turned on and turned off, respectively. The first switching unit (11) comprises:
2. The drive protection circuit (100) according to claim 1, characterized in that a first switching device (111), a first electrode of the first switching device (111) being connected to the predetermined circuit terminal (20), a second electrode of the first switching device (111) being connected to the first end of the first voltage limiting circuit (31); a first capacitor (112), a first end of the first capacitor (112) being connected to the first electrode of the first switching device (111), a second end of the first capacitor (112) being connected to a control end of the first switching device (111); and a first diode (113), a cathode of the first diode (113) being connected to the first electrode of the first switching device (111), an anode of the first diode (113) being connected to the second electrode of the first switching device (111). The second switching unit (12) comprises:
3. The drive protection circuit (100) according to claim 1, characterized in that a second switch device (121), a first electrode of the second switch device (121) being connected to a second end of the first voltage limiting circuit (31), a second electrode of the second switch device (121) being connected to a second end of the second voltage limiting circuit (32), and a control end of the second switch device (121) being connected to a first end of the second voltage limiting circuit (32); a second capacitor (122), a first end of the second capacitor (122) being connected to the first electrode of the second switch device (121), and a second end of the second capacitor (122) being connected to the control end of the second switch device (121); and a second diode (123), a cathode of the second diode (123) being connected to the first electrode of the second switch device (121), and an anode of the second diode (123) being connected to the second electrode of the second switch device (121).
4. The drive protection circuit (100) according to claim 1, characterized in that The first voltage limiting circuit (31) comprises: a first triode (311), an emitter of the first triode (311) being connected to a second end of the first switch unit (11); a first resistor (312), a first end of the first resistor (312) being connected to the emitter of the first triode (311), and a second end of the first resistor (312) being connected to a base of the first triode (311); and a second resistor (313), a first end of the second resistor (313) being connected to a collector of the first triode (311), and a second end of the second resistor (313) being connected to the first ground.
5. The drive protection circuit (100) according to claim 4, characterized in that The first voltage limiting circuit (31) further comprises a third diode (314), a cathode of the third diode (314) being connected to the emitter of the first triode (311), and an anode of the third diode (314) being connected to the collector of the first triode (311).
6. The drive protection circuit (100) according to claim 1, characterized in that The second voltage limiting circuit (32) comprises: a second triode (321), an emitter of the second triode (321) being connected to a control end of the second switch unit (12); a third resistor (322), a first end of the third resistor (322) being connected to the emitter of the second triode (321), and a second end of the third resistor (322) being connected to a base of the second triode (321); and a fourth resistor (323), a first end of the fourth resistor (323) being connected to a collector of the second triode (321), and a second end of the fourth resistor (323) being connected to the second ground.
7. The drive protection circuit (100) according to claim 6, characterized in that The second voltage limiting circuit (32) further comprises a fourth diode (324), a cathode of the fourth diode (324) being connected to the emitter of the second triode (321), and an anode of the fourth diode (324) being connected to the collector of the second triode (321).
8. The drive protection circuit (100) according to claim 1, characterized in that The first control circuit (41) comprises: a first MOS tube (511), a drain of the first MOS tube (511) being connected to the first power supply (51); a second MOS transistor (512) having a drain connected to a source of the first MOS transistor (511), a source connected to the first ground; and a first driving unit (510) connected to gates of the first MOS transistor (511) and the second MOS transistor (512).
9. The drive protection circuit (100) according to claim 1, characterized in that The second control circuit (42) comprises: a third MOS transistor (521) having a drain connected to the second power supply (52); a fourth MOS transistor (522) having a drain connected to a source of the third MOS transistor (521), a source connected to the second ground; and a second driving unit (520) connected to gates of the third MOS transistor (521) and the fourth MOS transistor (522).