Driving circuit for driving IGBT (Insulated Gate Bipolar Translator) and IGBT
By designing an IGBT driving circuit including pulse generator, switch tube, transformer and full-bridge rectifier, the problems of incomplete isolation voltage and slow signal transmission in the prior art are solved, and more efficient isolation and faster signal transmission are achieved.
Patent Information
- Application Number
- CN202411584839.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-03-28
AI Technical Summary
The existing IGBT driver circuits have problems such as incomplete isolation voltage and slow signal transmission speed.
A driving circuit is designed including a pulse generator, four switching tubes, two transformers and a full bridge rectifier. The switch tube is controlled by generating a flip signal and a reverse signal through the pulse generator, the transformer's windings are used to achieve high insulation voltage, and the signal transmission speed is improved through the magnetic field in real time.
It achieves a more thorough isolation voltage and faster signal transmission speed, improving the performance of IGBT driver circuits.
Smart Images
Figure CN119727687A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a driving circuit for driving an IGBT and the IGBT, and belongs to the field of power electronics. Background Art
[0002] Currently, the commonly used insulated gate bipolar transistor (IGBT) drive circuit generally adopts an optocoupler isolation drive circuit. Figure 1 . Figure 1 It is an existing optocoupler isolation type drive circuit, such as Figure 1 As shown in FIG. 1 , the push-pull circuit composed of the photocoupler and the transistor is combined to achieve signal transmission and electrical isolation. However, the optocoupler drive circuit has the following disadvantages: (1) The isolation voltage is limited by the insulation voltage of the optocoupler chip, which may result in incomplete isolation; (2) The signal transmission speed is limited by the speed of the optocoupler, which makes the application scenario not universal. Summary of the invention
[0003] The object of the present invention is to provide a driving circuit for driving an IGBT and an IGBT, so as to solve the problems of incomplete isolation voltage and slow signal transmission speed in the prior art.
[0004] To achieve the above object, the solution of the present invention includes: A driving circuit for driving an IGBT of the present invention comprises: a pulse generator, four switch tubes, two transformers and a full-bridge rectifier; The pulse generator is used for flipping along the rising edge of the input pulse signal to obtain a first flip signal and outputting the first flip signal to the control end of the first switch tube, flipping along the falling edge of the input pulse signal to obtain a second flip signal and outputting the second flip signal to the control end of the third switch tube, inverting the first flip signal to obtain a first inverted signal and outputting the first inverted signal to the control end of the second switch tube, inverting the second flip signal to obtain a second inverted signal and outputting the second inverted signal to the control end of the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all turned on when their control ends are at a high level, and are turned off when they are at a low level; The primary coil of the first transformer and the primary coil of the second transformer each include two windings connected in series with the same end direction; the first winding in the primary coil of the first transformer is connected in series with the on-off end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the on-off end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the on-off end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the on-off end of the third switch tube and then connected to the two ends of the power supply; After the secondary coil of the first transformer is connected to the secondary coil of the second transformer at opposite ends, the like ends are connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier.
[0005] Further, the pulse generator includes a field programmable gate array or a discrete device.
[0006] Furthermore, the four switching tubes are triodes.
[0007] Furthermore, a current limiting resistor for current limiting is connected in series on the line between the pulse generator and each switch tube.
[0008] Furthermore, a current limiting resistor for current limiting is connected in series on a line of the full-bridge rectifier for connecting the gate of the IGBT to be driven.
[0009] An IGBT of the present invention includes a drive circuit, which includes: a pulse generator, four switch tubes, two transformers and a full-bridge rectifier; The pulse generator is used for flipping along the rising edge of the input pulse signal to obtain a first flip signal and outputting the first flip signal to the control end of the first switch tube, flipping along the falling edge of the input pulse signal to obtain a second flip signal and outputting the second flip signal to the control end of the third switch tube, inverting the first flip signal to obtain a first inverted signal and outputting the first inverted signal to the control end of the second switch tube, inverting the second flip signal to obtain a second inverted signal and outputting the second inverted signal to the control end of the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all turned on when their control ends are at a high level, and are turned off when they are at a low level; The primary coil of the first transformer and the primary coil of the second transformer each include two windings connected in series with the same end direction; the first winding in the primary coil of the first transformer is connected in series with the on-off end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the on-off end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the on-off end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the on-off end of the third switch tube and then connected to the two ends of the power supply; After the secondary coil of the first transformer is connected to the secondary coil of the second transformer at opposite ends, the same end is connected to the gate and emitter of the IGBT through a full-bridge rectifier.
[0010] Further, the pulse generator includes a field programmable gate array or a discrete device.
[0011] Furthermore, the four switching tubes are triodes.
[0012] Furthermore, a current limiting resistor for current limiting is connected in series on the line between the pulse generator and each switch tube.
[0013] Furthermore, a current limiting resistor for current limiting is connected in series on a line of the full-bridge rectifier for connecting the gate of the IGBT.
[0014] The beneficial effects of the present invention are as follows: as a pioneering invention, the present invention provides a driving circuit and an IGBT for driving an IGBT, firstly using a pulse generator, flipping along the rising edge of an input pulse signal to obtain a first flipping signal to control a first switch tube, flipping along the falling edge of the input pulse signal to obtain a second flipping signal to control a third switch tube, inverting the first flipping signal to obtain a first inverted signal to control the second switch tube, inverting the second flipping signal to obtain a second inverted signal to control the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all used to be turned on at a high level and turned off at a low level; then, the primary coil of the first transformer and the primary coil of the second transformer both include Two windings connected in series with the same end direction; the first winding in the primary coil of the first transformer is connected in series with the conduction and cutoff end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the conduction and cutoff end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the conduction and cutoff end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the conduction and cutoff end of the third switch tube and then connected to the two ends of the power supply; finally, the secondary coil of the first transformer and the secondary coil of the second transformer are connected at the opposite ends, and the same end is connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier. By designing the windings of the two transformers, a high insulation voltage can be achieved, making the isolation voltage more thorough; the magnetic field of the transformer is used to transmit information in real time, thereby improving the transmission speed of the signal. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is an existing optocoupler isolation type drive circuit; Figure 2 is a schematic structural diagram of a driving circuit for driving an IGBT provided by an embodiment of the present invention; Figure 3 is a structural schematic diagram of a pulse generator provided by an embodiment of the present invention; Figure 4 is a waveform diagram of an output waveform of a pulse generator provided by an embodiment of the present invention; Figure 5 is a waveform diagram of output waveforms of a first transformer and a second transformer respectively provided in an embodiment of the present invention; Figure 6 It is a waveform diagram of a waveform obtained by subtracting the waveforms output by two transformers and a waveform diagram of a waveform output by a full-bridge rectifier provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0016] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0017] The concept of the present invention is to use two transformers to provide driving voltage for IGBT.
[0018] Specifically, a pulse generator is first used to flip along the rising edge of the input pulse signal to obtain a first flip signal to control the first switch tube, flip along the falling edge of the input pulse signal to obtain a second flip signal to control the third switch tube, invert the first flip signal to obtain a first inverted signal to control the second switch tube, and invert the second flip signal to obtain a second inverted signal to control the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all used to be turned on at a high level and turned off at a low level; then, the primary coil of the first transformer and the primary coil of the second transformer each include two windings connected in series with the same end direction; the first transformer The first winding in the primary coil of the transformer is connected in series with the conduction and cutoff end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the conduction and cutoff end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the conduction and cutoff end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the conduction and cutoff end of the third switch tube and then connected to the two ends of the power supply; finally, the secondary coil of the first transformer and the secondary coil of the second transformer are connected at the opposite ends, and the same end is connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier. By designing the windings of the two transformers, a high insulation voltage can be achieved, making the isolation voltage more thorough; the magnetic field of the transformer is used to transmit information in real time, which improves the transmission speed of the signal.
[0019] An embodiment of a driving circuit for driving an IGBT: Figure 2 is a schematic diagram of a driving circuit for driving an IGBT provided by an embodiment of the present invention, such as Figure 2 As shown, the driving circuit includes: a pulse generator 10, four switching tubes, two transformers and a full-bridge rectifier.
[0020] The four switch tubes are a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4; the two transformers are a first transformer T1 and a second transformer T2.
[0021] Specifically, the pulse generator 10 includes an input end and four output ends, the input end is used to receive the input pulse signal S0, and the four output ends are respectively connected to the control end of the first switch tube Q1, the control end of the second switch tube Q2, the control end of the third switch tube Q3 and the control end of the fourth switch tube Q4.
[0022] The primary coil of the first transformer T1 and the primary coil of the second transformer T2 both include two windings connected in series with the same direction of the same-name end. The first winding of the primary coil of the first transformer T1 has one end with the same-name end connected in series with the on-off end of the second switch tube Q2 and then connected to the negative pole of the power supply V0, and the positive pole of the power supply V0 is connected to one end with the opposite-name end of the first winding of the primary coil of the first transformer T1; the second winding of the primary coil of the first transformer T1 has one end with the opposite-name end connected in series with the on-off end of the first switch tube Q1 and then connected to the negative pole of the power supply V0, and the positive pole of the power supply V0 is also connected to one end with the same-name end of the second winding of the primary coil of the first transformer T1.
[0023] One end of the first winding in the primary coil of the second transformer T2 with a like-name end is connected in series with the on-off end of the fourth switch tube Q4 and then connected to the negative electrode of the power supply V0, and the positive electrode of the power supply V0 is also connected to one end of the first winding in the primary coil of the second transformer T2 with an opposite-name end; one end of the second winding in the primary coil of the second transformer T2 with an opposite-name end is connected in series with the on-off end of the third switch tube Q3 and then connected to the negative electrode of the power supply V0, and the positive electrode of the power supply V0 is also connected to one end of the second winding in the primary coil of the second transformer T2 with a like-name end.
[0024] The secondary coil of the first transformer T1 is connected to the secondary coil of the second transformer T2 at opposite ends, and the same end is connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier.
[0025] As another optional implementation, the first transformer T1 and the second transformer T2 are each connected to a power source, that is, the first transformer T1 is connected to the power source V0, and the second transformer is connected to the power source V1. The power source V0 and the power source V1 are unipolar power sources; the power source V0 and the power source V1 can provide the same power supply voltage or different power supply voltages, which is not particularly limited in the present invention. In order to reduce the circuit volume, the following takes the first transformer T1 and the second transformer T2 connected to the same power source V0 as an example for exemplary description.
[0026] Among them, the pulse generator 10 is used to flip along the rising edge of the input pulse signal to obtain a first flip signal and output the first flip signal to the control end of the first switch tube Q1, flip along the falling edge of the input pulse signal to obtain a second flip signal and output the second flip signal to the control end of the third switch tube Q3, invert the first flip signal to obtain a first inverted signal and output the first inverted signal to the control end of the second switch tube Q2, invert the second flip signal to obtain a second inverted signal and output the second inverted signal to the control end of the fourth switch tube Q4.
[0027] The pulse generator 10 may be a field programmable gate array (FPGA) or a discrete device, etc., and the present invention does not specifically limit this. In order to facilitate the adjustment of the duty cycle of the input pulse signal, the pulse generator 10 is an FPGA as an example for exemplary description.
[0028] The structure of the pulse generator 10 can be referred to Figure 3 . Figure 3 is a schematic diagram of the structure of a pulse generator provided by an embodiment of the present invention, such as Figure 3 As shown, the FPGA may include a rising edge flip module 101, a falling edge flip module 102, and a pulse inversion module 103. The rising edge flip module 101 is respectively connected to the control end of the first switch tube Q1 and the pulse inversion module 103; the falling edge flip module 102 is respectively connected to the control end of the third switch tube Q1 and the pulse inversion module 103; the pulse inversion module 103 is respectively connected to the second switch tube Q2 and the fourth switch tube Q4.
[0029] As another optional implementation, the rising edge flip module 101 and the falling edge flip module 102 can each be connected to a corresponding pulse inversion circuit. The present invention does not specifically limit whether the rising edge flip module 101 and the falling edge flip module 102 are connected to the same pulse inversion circuit or are each connected to a corresponding pulse inversion circuit; in order to reduce circuit complexity and production costs, the following explanation is given by taking the case where the rising edge flip module 101 and the falling edge flip module 102 are connected to the same pulse inversion circuit as an example.
[0030] It is understandable that the rising edge flip module 101, the falling edge flip module 102 and the pulse inversion module 103 can all be product modules with actual functions, or programs divided according to corresponding functions, etc., and the present invention does not make any special limitation on this.
[0031] Combine the following Figure 4 The operating principle of the pulse generator 10 will be described.
[0032] Figure 4 is a waveform diagram of a pulse generator output waveform provided by an embodiment of the present invention, such as Figure 4 As shown, the input pulse signal S0 is generally generated by the control chip and the weak current control circuit, and its high level typical value is 3.3 volts (V) or 5V, and the low level typical value is 0V. It can be understood that the high level and low level of the input pulse signal S0 can also be other values, and the present invention does not specifically limit this. The following takes the high level of the input pulse signal S0 as 3.3V and the low level as 0V as an example for exemplary description.
[0033] The rising edge flip module 101 in the pulse generator 10 flips along the rising edge of the input pulse signal S0 to obtain the first flip signal S1. For example, the initial level of the first flip signal S1 is a low level. When encountering the rising edge of the input pulse signal S0, it flips to obtain a high level. When encountering the next rising edge of the input pulse signal S0, it flips again to obtain a low level; and so on, finally a complete waveform diagram is obtained.
[0034] The falling edge flip module 102 in the pulse generator 10 flips along the falling edge of the input pulse signal S0 to obtain a second flip signal S3. For example, the initial level of the second flip signal S3 is a low level. When encountering the falling edge of the input pulse signal S0, it flips to obtain a high level. When encountering the next falling edge of the input pulse signal S0, it flips again to obtain a low level. This process repeats and finally obtains a complete waveform diagram.
[0035] The inversion module 103 in the pulse generator 10 inverts the first flip signal S1 to obtain a first inversion signal S2. For example, when the first flip signal S1 is at a low level, the first flip signal S1 is inverted to obtain a high level; when the first flip signal S1 is at a high level, the first flip signal S1 is inverted to obtain a low level; and so on, finally a complete waveform diagram is obtained.
[0036] The inversion module 103 in the pulse generator 10 inverts the second flip signal S3 to obtain a second inversion signal S4. For example, when the second flip signal S3 is at a low level, the second flip signal S3 is inverted to obtain a high level; when the second flip signal S3 is at a high level, the second flip signal S3 is inverted to obtain a low level; and so on, finally a complete waveform diagram is obtained.
[0037] The first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 , and the fourth switch tube Q4 are all used for being turned on when the control terminals thereof are at a high level, and being turned off when the control terminals thereof are at a low level.
[0038] Among them, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4 can all be bipolar junction transistors (Bipolar Junction Transistor, BJT), and can also be metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc., and the present invention does not specifically limit this. In order to reduce costs, the following takes the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4 as BJT tubes as an example for exemplary description.
[0039] Among them, BJT tubes can be divided into N-type BJT tubes and P-type BJT tubes. N-type BJT tubes have the characteristics of "high pass and low break", and P-type BJT tubes have the characteristics of "low pass and high break". Combined with the characteristics of the circuit, the following takes the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 as N-type BJT tubes as an example for exemplary description.
[0040] When the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are all N-type BJT tubes, the specific connection structure in the driving circuit is as follows: the base of the first switch tube Q1 is connected to the output end of the rising edge flip module 101 in the pulse generator 10, the collector of the first switch tube Q1 is connected to one end of the second winding of the primary coil of the first transformer T1 with an opposite-name terminal, and the emitter of the first switch tube Q1 is connected to the negative electrode of the power supply V0. The base of the second switch tube Q2 is connected to the output end of the pulse inversion 103 in the pulse generator 10, the collector of the second switch tube Q2 is connected to one end of the first winding of the primary coil of the first transformer T1 with a same-name terminal, and the emitter of the second switch tube Q2 is connected to the negative electrode of the power supply V0. The base of the third switch tube Q3 is connected to the output end of the falling edge flip module 102 in the pulse generator 10, the collector of the third switch tube Q3 is connected to one end of the second winding of the primary coil of the second transformer T2 with an opposite-name terminal, and the emitter of the third switch tube Q3 is connected to the negative electrode of the power supply V0. The base of the fourth switch tube Q4 is connected to the output end of the pulse inversion 103 in the pulse generator 10, the collector of the fourth switch tube Q4 is connected to one end of the first winding of the primary coil of the second transformer T1 with the same end, and the emitter of the fourth switch tube Q4 is connected to the negative electrode of the power supply V0.
[0041] Combine the following Figure 5 , illustrating the waveforms output by the first transformer T1 and the second transformer T2.
[0042] Figure 5 is a waveform diagram of output waveforms of a first transformer and a second transformer respectively provided in an embodiment of the present invention, such as Figure 5 As shown, the first switching tube Q1 is turned on and off controlled by the first flip signal S1, the second switching tube Q2 is turned on and off controlled by the first inversion signal S2, the third switching tube Q3 is turned on and off controlled by the second flip signal S3, and the fourth switching tube Q4 is turned on and off controlled by the second inversion signal S4.
[0043] Since the first flip signal S1 is flipped along the rising edge of the input pulse signal S0, the second flip signal S3 is flipped along the falling edge of the input pulse signal S0, the first inverted signal S2 is obtained by inverting the first flip signal S1, and the second inverted signal S4 is obtained by inverting the second flip signal S2, there is a time difference between the rising edge and the falling edge of the output pulse signal S0, so there is a time difference between the first flip signal S1 and the second flip signal S2, which will cause a phase difference between the first transformer T1 and the second transformer T2.
[0044] Since the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are all turned on at a high level and turned off at a low level, the first switch tube Q1 and the second switch tube Q2 are turned on alternately, and the third switch tube Q3 and the fourth switch tube Q4 are turned on alternately.
[0045] When the first switch tube Q1 is turned on, the second switch tube Q2 is turned off, and the first transformer T1 outputs a voltage with an amplitude of +15 volts (V); when the first switch tube Q1 is turned off, the second switch tube Q2 is turned on, and the first transformer T1 outputs a voltage with an amplitude of -15V, and so on. Finally, the first transformer T1 outputs a square wave signal with a voltage of ±15V, that is, signal S5.
[0046] When the third switch tube Q3 is turned on, the fourth switch tube Q4 is turned off, and the second transformer T2 outputs a voltage with an amplitude of +15V; when the third switch tube Q3 is turned off, the fourth switch tube Q4 is turned on, and the second transformer T2 outputs a voltage with an amplitude of -15V, and so on. Finally, the second transformer T2 outputs a square wave signal with a voltage of ±15V, that is, signal S6.
[0047] The amplitude of the voltage square wave signal S5 output by the first transformer T1 depends on the amplitude of the power supply V0 and the number of turns of the primary coil and the secondary coil of the first transformer T1; the amplitude of the voltage square wave signal S6 output by the second transformer T2 depends on the amplitude of the power supply V0 and the number of turns of the primary coil and the secondary coil of the second transformer T2. By changing the windings of each transformer, a high insulation voltage can be achieved.
[0048] In order to prevent excessive current from damaging the switch tubes, as an optional implementation, the drive circuit for driving the IGBT provided in the embodiment of the present invention may also include a first current limiting resistor R1, a second current limiting resistor R2, a third current limiting resistor R3 and a fourth current limiting resistor R4.
[0049] Specifically, the first current limiting resistor R1 is connected in series between the rising edge flip module 101 and the base of the first switch Q1; the second current limiting resistor R2 is connected in series between the pulse inversion module 103 and the base of the second switch Q2; the third current limiting resistor R3 is connected in series between the falling edge flip module 102 and the base of the third switch Q3; the fourth current limiting resistor R4 is connected in series between the pulse inversion module 103 and the base of the fourth switch Q4.
[0050] In order to prevent the driving current from being too large and causing damage to the IGBT to be driven, as an optional implementation, a fifth current limiting resistor R5 for current limiting is connected in series between the full-bridge rectifier and the gate of the IGBT to be driven.
[0051] The IGBT to be driven is an IGBT having a body diode D5.
[0052] Combine the following Figure 6 How to form the drive signal S8 of the IGBT to be driven is described below.
[0053] Figure 6 1 is a waveform diagram of a waveform obtained by subtracting the waveforms output by two transformers and a waveform diagram of a waveform output by a full-bridge rectifier provided by an embodiment of the present invention, such as Figure 6 As shown, since there is a phase difference between the voltage square wave signal S5 output by the first transformer T1 and the voltage square wave signal S6 output by the second transformer T3, in order to eliminate the influence of the phase difference and ensure the stability and accuracy of the voltage, it is necessary to subtract the square wave signal S5 output by the first transformer T1 and the square wave signal S6 output by the second transformer T2 to output a positive and negative pulse signal S7 with adjustable width.
[0054] Among them, the positive and negative pulse signal S7 is a bipolar signal. Therefore, the driving circuit for driving IGBT provided in the embodiment of the present invention can use a unipolar power supply to output a bipolar signal; the amplitude of the positive pulse of the positive and negative pulse signal S7 is +30V, and the amplitude of the negative pulse is -30V. The amplitude of the positive and negative pulses depends on the amplitude of the voltage square wave signal S5 output by the first transformer T1 and the amplitude of the voltage square wave signal S6 output by the second transformer T2.
[0055] Among them, "adjustable width" refers to the adjustable duty cycle of the positive and negative pulse signals S7. It can be understood that, since the pulse generator 10 includes an FPGA, the FPGA can adjust the duty cycle of the input pulse signal, thereby adjusting the duty cycle of the first flip signal S1 and the second flip signal S2. Correspondingly, the duty cycle of the first inverted signal S1 and the second inverted signal S2 will also change, resulting in changes in the duty cycle of the voltage square wave signal S5 output by the first transformer T1 and the voltage square wave signal S6 output by the second transformer T2, and finally the duty cycle of the positive and negative pulse signals S7 also changes.
[0056] The full-bridge rectifier rectifies the positive and negative pulse signals S7 to obtain a drive signal S8. The drive signal S8 is a square wave signal with a high level of +30V and a low level of 0V. Since the amplitude of the drive signal S8 is +30V, which is greater than the voltage provided by the power supply V0, the drive power is large. For the IGBT to be driven, the drive voltage with an amplitude of +30V is a relatively large drive voltage, which can make the IGBT to be driven turn on quickly, reducing the risk of drive failure.
[0057] After explaining the connection relationship of the driving circuit and the generation process of each waveform, the working principle of the driving circuit for driving the IGBT provided by the embodiment of the present invention is described below.
[0058] The pulse generator 10 flips the output pulse signal S0 along its rising edge to obtain a first flip signal S1, and outputs the first flip signal S1 to the first switch tube Q1; the pulse generator 10 flips the output pulse signal S0 along its falling edge to obtain a second flip signal S3, and outputs the second flip signal S3 to the third switch tube Q3; the pulse generator 10 inverts the first flip signal S1 to obtain a first inverted signal S2, and outputs the first inverted signal S2 to the second switch tube Q2; the pulse generator 10 inverts the second flip signal S3 to obtain a second inverted signal S4, and outputs the second inverted signal S4 to the fourth switch tube Q4.
[0059] The first switch tube Q1 and the second switch tube Q2 are turned on alternately, and the third switch tube Q3 and the fourth switch tube Q4 are turned on alternately, and finally a positive and negative pulse signal S7 is formed. When the positive and negative pulse signal S7 is a positive pulse, the first diode D1 and the third diode D3 in the full-bridge rectifier rectify the positive and negative pulse signal S7 and drive the IGBT to turn on; when the positive and negative pulse signal S7 is a negative pulse, the second diode D2 and the fourth diode D4 in the full-bridge rectifier rectify the positive and negative pulse signal S7 and drive the IGBT to turn on.
[0060] The embodiment of the present invention provides a driving circuit for driving an IGBT. The pulse generator is first used to flip along the rising edge of an input pulse signal to obtain a first flip signal to control a first switch tube, flip along the falling edge of the input pulse signal to obtain a second flip signal to control a third switch tube, invert the first flip signal to obtain a first inverted signal to control the second switch tube, and invert the second flip signal to obtain a second inverted signal to control the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all used to be turned on at a high level and turned off at a low level; then, the primary coil of the first transformer and the primary coil of the second transformer each include two series-connected, same-named terminals. The first winding in the primary coil of the first transformer is connected to the on-off end of the second switch tube in series and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected to the on-off end of the first switch tube in series and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected to the on-off end of the fourth switch tube in series and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected to the on-off end of the third switch tube in series and then connected to the two ends of the power supply; finally, the secondary coil of the first transformer and the secondary coil of the second transformer are connected at the opposite ends, and the same end is connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier. By designing the windings of the two transformers, a high insulation voltage can be achieved, making the isolation voltage more thorough; the magnetic field of the transformer is used to transmit information in real time, which improves the transmission speed of the signal.
[0061] An embodiment of an IGBT: An IGBT provided in an embodiment of the present invention includes a driving circuit. The driving circuit can refer to the relevant description about the driving circuit in the above-mentioned embodiment of "a driving circuit for driving an IGBT", which will not be repeated here.
[0062] An IGBT provided in an embodiment of the present invention can achieve the same beneficial effects as the aforementioned driving circuit for driving the IGBT, which will not be described in detail here.
Claims
1. A driving circuit for driving an IGBT, characterized in that: include: Pulse generator, four switching tubes, two transformers and full-bridge rectifier; The pulse generator is used for flipping along the rising edge of the input pulse signal to obtain a first flip signal and outputting the first flip signal to the control end of the first switch tube, flipping along the falling edge of the input pulse signal to obtain a second flip signal and outputting the second flip signal to the control end of the third switch tube, inverting the first flip signal to obtain a first inverted signal and outputting the first inverted signal to the control end of the second switch tube, inverting the second flip signal to obtain a second inverted signal and outputting the second inverted signal to the control end of the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all turned on when their control ends are at a high level, and are turned off when they are at a low level; The primary coil of the first transformer and the primary coil of the second transformer each include two windings connected in series with the same end direction; the first winding in the primary coil of the first transformer is connected in series with the on-off end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the on-off end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the on-off end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the on-off end of the third switch tube and then connected to the two ends of the power supply; After the secondary coil of the first transformer is connected to the secondary coil of the second transformer at opposite ends, the like ends are connected to the gate and emitter of the IGBT to be driven through a full-bridge rectifier.
2. The driving circuit for driving an IGBT according to claim 1, characterized in that: The pulse generator includes a field programmable gate array or a discrete device.
3. The driving circuit for driving an IGBT according to claim 1, characterized in that: The four switch tubes are triodes.
4. The driving circuit for driving an IGBT according to claim 1, characterized in that: A current limiting resistor for current limiting is connected in series on the line between the pulse generator and each switch tube.
5. The driving circuit for driving an IGBT according to any one of claims 1 to 4, characterized in that: A current limiting resistor for current limiting is connected in series on a line of the full-bridge rectifier for connecting the gate of the IGBT to be driven.
6. An IGBT, comprising a drive circuit, characterized in that: The driving circuit includes: a pulse generator, four switch tubes, two transformers and a full-bridge rectifier; The pulse generator is used for flipping along the rising edge of the input pulse signal to obtain a first flip signal and outputting the first flip signal to the control end of the first switch tube, flipping along the falling edge of the input pulse signal to obtain a second flip signal and outputting the second flip signal to the control end of the third switch tube, inverting the first flip signal to obtain a first inverted signal and outputting the first inverted signal to the control end of the second switch tube, inverting the second flip signal to obtain a second inverted signal and outputting the second inverted signal to the control end of the fourth switch tube; the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all turned on when their control ends are at a high level, and are turned off when they are at a low level; The primary coil of the first transformer and the primary coil of the second transformer each include two windings connected in series with the same end direction; the first winding in the primary coil of the first transformer is connected in series with the on-off end of the second switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the first transformer is connected in series with the on-off end of the first switch tube and then connected to the two ends of the power supply; the first winding in the primary coil of the second transformer is connected in series with the on-off end of the fourth switch tube and then connected to the two ends of the power supply, and the second winding in the primary coil of the second transformer is connected in series with the on-off end of the third switch tube and then connected to the two ends of the power supply; After the secondary coil of the first transformer is connected to the secondary coil of the second transformer at opposite ends, the same end is connected to the gate and emitter of the IGBT through a full-bridge rectifier.
7. The IGBT according to claim 6, characterized in that: The pulse generator includes a field programmable gate array or a discrete device.
8. The IGBT according to claim 6, characterized in that: The four switch tubes are triodes.
9. The IGBT according to claim 6, characterized in that: A current limiting resistor for current limiting is connected in series on the line between the pulse generator and each switch tube.
10. The IGBT according to any one of claims 6 to 9, characterized in that: A current limiting resistor for current limiting is connected in series on a line of the full-bridge rectifier for connecting the gate of the IGBT.