Driving circuit and driving system

Abstract

The utility model discloses a driving circuit and a driving system, and the driving circuit comprises a first driving module which is connected with a power device; the second driving module is connected with the power device and the first driving module; the control module is connected with the first driving module and the second driving module, and the control module is used for controlling the first driving module to be switched on to drive the power device to act when the state of charge of the battery is larger than a preset threshold value and controlling the second driving module to be switched off to drive the power device to act when the state of charge of the battery is smaller than or equal to the preset threshold value. And controlling the first driving module and the second driving module to be switched on at the same time so as to drive the power device to act. By adopting the driving loop, the switching speed of a power device can be effectively increased while voltage overshoot / electromagnetic interference is avoided, the switching loss of the power device is reduced, and the system efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of drive systems, in particular to a drive circuit and a drive system. Background Art

[0002] In the related technology, the energy of electric vehicles is provided by high-voltage batteries, and the power module composed of power devices IGBT (Insulated Gate Bipolar Transistor) or SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) converts its direct current into three-phase alternating current to drive the motor. The switching state of the power device in the power module is controlled by the drive signal emitted by the microprocessor in the motor control system after being isolated and amplified by the drive circuit composed of the gate driver and related components. That is, the drive circuit converts the drive signal emitted by the microprocessor into a high-voltage, high-current pulse to control the gate of the IGBT or MOSFET to turn it on or off.

[0003] However, due to the existence of stray inductance inside the power device, the voltage of the power device overshoots during switching transients, causing electromagnetic interference problems. In order to suppress electromagnetic interference, a larger gate resistor is used to reduce the speed at which the gate current passes through the power device to avoid the problem of electromagnetic interference caused by voltage overshoot. However, increasing the gate resistance will increase the switching time and increase the loss, reducing the system efficiency, making it impossible to take into account the system efficiency while avoiding voltage overshoot / electromagnetic interference. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a driving circuit, which can effectively speed up the switching speed of power devices, reduce the switching loss of power devices, and improve system efficiency while avoiding voltage overshoot / electromagnetic interference.

[0005] A second purpose of the present invention is to provide a driving system.

[0006] In order to solve the above problems, the first aspect of the utility model provides a driving circuit, comprising: a first driving module, the first driving module is connected to a power device; a second driving module, the second driving module is connected to the power device and the first driving module; a control module, the control module is connected to the first driving module and the second driving module, the control module is used to control the first driving module to be turned on to drive the power device to operate when the battery state of charge is greater than a preset threshold, and to control the first driving module and the second driving module to be turned on at the same time to drive the power device to operate when the battery state of charge is less than or equal to the preset threshold.

[0007] According to the driving circuit of the utility model, a second driving module is added on the basis of the original first driving module. When the voltage overshoot tolerance is small as determined by the battery charge state, the control module controls the first driving module to provide driving function alone to reduce the driving current of the power device, thereby avoiding the problem of voltage overcharge / electromagnetic interference. When the voltage overshoot tolerance is large as determined by the battery charge state, the control module controls the first driving module and the second driving module to jointly play a driving role to increase the driving current of the power device, thereby effectively speeding up the switching speed of the power device, reducing the switching loss of the power device, and improving the system efficiency.

[0008] In some embodiments, the first driving module includes: a driver chip, the driver chip includes a signal processing unit, a switch unit, a positive power supply terminal, a PWM signal receiving terminal and a driving connection terminal, the positive power supply terminal is used to connect a driving power supply to power the driver chip, the PWM signal receiving terminal is connected to the PWM signal output terminal of the control module, the signal processing unit is connected to the PWM signal receiving terminal, the first end of the switch unit is connected to the positive power supply terminal, the second end of the switch unit is connected to the driving connection terminal, and the control end of the switch unit is connected to the signal processing unit; a resistor unit, the first end of the resistor unit is connected to the driving connection terminal, and the second end of the resistor unit is connected to the gate of the power device.

[0009] In some embodiments, the PWM signal receiving end includes a PWM-ON signal receiving end, the PWM-ON signal receiving end is used to receive a PWM-ON signal, and the driving connection end includes a first driving connection end; the switch unit includes a first MOS tube, the first end of the first MOS tube is connected to the positive power supply end, the second end of the first MOS tube is connected to the first driving connection end, and the control end of the first MOS tube is connected to the signal processing unit; the resistor unit includes a first driving resistor, the first end of the first driving resistor is connected to the first driving connection end, and the second end of the first driving resistor is connected to the gate of the power device; wherein the signal processing unit controls the positive power supply end, the first MOS tube, the first driving resistor and the gate of the power device to conduct the loop according to the PWM-ON signal to drive the power device to turn on.

[0010] In some embodiments, the second driving module includes: a first driving unit, a first end of the first driving unit is connected to the first control end of the control module, a second end of the first driving unit is connected to the first end of the first driving resistor and the first driving connection end, and a third end of the first driving unit is connected to the second end of the first driving resistor and the gate of the power device; wherein, during the conduction of the power device, if the battery state of charge is less than or equal to a preset threshold, the control module controls the first driving unit to be turned on; during the conduction of the power device, if the battery state of charge is greater than the preset threshold, the control module controls the first driving unit to be disconnected.

[0011] In some embodiments, the first driving unit includes: a first optocoupler, a first end of the first optocoupler is used to receive a turn-on control signal provided by the first control end, a second end of the first optocoupler is grounded, and a third end of the first optocoupler is connected to the ground end of the driver chip; a first resistor, a first end of the first resistor is connected to a fourth end of the first optocoupler; a second MOS transistor, a gate of the second MOS transistor is connected to the second end of the first resistor, and a source of the second MOS transistor is connected to a first end of the first driving resistor and the first driving connection end; a second resistor, a first end of the second resistor is connected to the gate of the second MOS transistor, and a second end of the second resistor is connected to the source of the second MOS transistor; a third resistor, a first end of the third resistor is connected to the drain of the second MOS transistor, and a second end of the third resistor is connected to the second end of the first driving resistor and the gate of the power device; wherein, when the first optocoupler is turned on, the loop where the positive power supply end, the first driving connection end, the second MOS transistor, the third resistor and the gate of the power device are located is turned on; when the first optocoupler is turned off, the loop where the positive power supply end, the first driving connection end, the second MOS transistor, the third resistor and the gate of the power device are located is disconnected.

[0012] In some embodiments, the driver chip further includes a negative power supply terminal, the PWM signal receiving terminal includes a PWM-OFF signal receiving terminal, the PWM-OFF signal receiving terminal is used to receive a PWM-OFF signal, and the driving connection terminal includes a second driving connection terminal; the switch unit includes a third MOS tube, a first end of the third MOS tube is connected to the second driving connection terminal, a second end of the third MOS tube is connected to the negative power supply terminal, and a control end of the third MOS tube is connected to the signal processing unit; the resistor unit includes a second driving resistor, a first end of the second driving resistor is connected to the second driving connection terminal, and a second end of the second driving resistor is connected to the gate of the power device; wherein the signal processing unit controls the negative power supply terminal, the third MOS tube, the second driving resistor, and the gate of the power device to be turned on according to the PWM-OFF signal to drive the power device to turn off.

[0013] In some embodiments, the second driving module includes: a second driving unit, a first end of the second driving unit is connected to the second control end of the control module, a second end of the second driving unit is connected to the first end of the second driving resistor and the second driving connection end, and a third end of the second driving unit is connected to the second end of the second driving resistor and the gate of the power device; wherein, during the shutdown process of the power device, if the battery state of charge is less than or equal to a preset threshold, the control module controls the second driving unit to turn on; during the shutdown process of the power device, if the battery state of charge is greater than the preset threshold, the control module controls the second driving unit to disconnect.

[0014] In some embodiments, the second driving unit includes: a second optical coupler, a first end of the second optical coupler is used to receive a turn-on control signal provided by the second control end, a second end of the second optical coupler is grounded, and a third end of the second optical coupler is connected to the ground end of the driver chip; a fourth resistor, a first end of the fourth resistor is connected to the fourth end of the second optical coupler; a fourth MOS tube, a gate of the fourth MOS tube is connected to the second end of the fourth resistor, and a drain of the fourth MOS tube is connected to the first end of the second driving resistor and the second driving connection end; a fifth resistor, a first end of the fifth resistor is connected to the gate of the fourth MOS tube, and a second end of the fifth resistor is connected to the drain of the fourth MOS tube; a sixth resistor, a first end of the sixth resistor is connected to the source of the fourth MOS tube, and a second end of the sixth resistor is connected to the second end of the second driving resistor and the gate of the power device; wherein, when the second optical coupler is turned on, the loop where the negative power supply end, the second driving connection end, the fourth MOS tube, the sixth resistor and the gate of the power device are located is turned on; when the second optical coupler is turned off, the loop where the negative power supply end, the second driving connection end, the fourth MOS tube, the sixth resistor and the gate of the power device are located is disconnected.

[0015] In some embodiments, the second driving module further includes: a buffer unit, and the buffer unit is disposed between the control module and the driving unit.

[0016] A second aspect of the utility model provides a driving system, characterized in that it includes: a power device; and the driving circuit described in the above embodiment, wherein the driving circuit is used to drive the power device to turn on or off.

[0017] According to the drive system of the utility model, through the drive circuit of the above embodiment, while avoiding voltage overshoot / electromagnetic interference, it is possible to effectively increase the switching speed of the power device, reduce the switching loss of the power device, and improve the system efficiency.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 It is a schematic diagram of power device losses;

[0021] Figure 2 is a topological schematic diagram of a driving circuit according to an embodiment of the utility model;

[0022] Figure 3 It is a curve diagram of voltage instantaneous overshoot, battery pack voltage and battery charge state according to an embodiment of the utility model;

[0023] Figure 4 It is a structural block diagram of a driving system according to an embodiment of the utility model.

[0024] Reference numerals:

[0025] Drive system 1000;

[0026] Driving circuit 100; power device 200;

[0027] A first driving module 10; a second driving module 20; a control module 30; a driver chip 11; a signal processing unit 110; a switch unit 111; a resistor unit 12; a first driving unit 21; and a second driving unit 22;

[0028] The first optical coupler U1, the second optical coupler U2, the first driving resistor R01, the second driving resistor R02, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, and the fourth MOS tube Q4. DETAILED DESCRIPTION

[0029] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0030] Power devices experience losses during switching transients due to voltage and current overlap, such as Figure 1As shown. The gate current (driving strength) determines the charging and discharging speeds ton and toff of the input capacitance of the power device. When the gate current increases, ton and toff decrease. If the gate current is too small, the power device loss increases. The gate driver must turn on the power device as efficiently as possible to reduce the switching loss. Increasing the intensity of the gate drive current can accelerate the switching speed and thus reduce the switching loss. However, due to the presence of stray inductance Ls inside the power module, this results in an increased voltage transient overshoot at the switching node during turn-off, thereby causing problems such as device voltage stress and electromagnetic interference. The greater the collector-emitter voltage overshoot, the greater the risk of overvoltage breakdown of the power device, because the collector-emitter voltage needs to satisfy Vce = Udc + Ls * di / dt < Vces, where Vce is the collector-emitter voltage, Udc is the bus voltage, and Vces is the maximum voltage that can be applied between the collector and emitter. The influence of the stray inductance Ls on the turn-off process greatly affects the available bus voltage Udc.

[0031] The traditional electromagnetic interference suppression method is to use a larger gate resistor Rg to reduce the speed di / dt of the gate current flowing through the power device, because if the gate resistor Rg is too small, it will cause too large a voltage overshoot, damage the power device, and generate greater electromagnetic interference. However, increasing the gate resistor Rg will significantly increase the switching time and increase the loss, reducing the system efficiency. Therefore, a trade-off needs to be made between efficiency and voltage overshoot / electromagnetic interference, resulting in the drive circuit not being able to achieve the optimal effect.

[0032] To solve the above problems, an embodiment of the first aspect of the present utility model provides a drive circuit. Using this drive circuit can effectively accelerate the switching speed of the power device, reduce the switching loss of the power device, and improve the system efficiency while avoiding voltage overshoot / electromagnetic interference.

[0033] Next, refer to Figure 2 to describe the drive circuit 100 according to an embodiment of the present utility model. As Figure 2 shown, the drive circuit 100 includes: a first drive module 10, a second drive module 20, and a control module 30.

[0034] Among them, the first drive module 10 is connected to the power device 200; the second drive module 20 is connected to the power device 200 and the first drive module 10; the control module 30 is connected to the first drive module 10 and the second drive module 20. The control module 30 is configured to control the first drive module 10 to turn on to drive the power device 200 to act when the state of charge of the battery is greater than a preset threshold, and to control the first drive module 10 and the second drive module 20 to turn on simultaneously to drive the power device 200 to act when the state of charge of the battery is less than or equal to the preset threshold.

[0035] Specifically, as Figure 3As shown, when the battery state of charge SOC is 100% to 80%, the bus voltage is high and the voltage overshoot tolerance is small, that is, the voltage range allowing the battery pack voltage to rise to the maximum voltage is small, for example, when the battery state of charge SOC is 100%, the voltage overshoot tolerance is 180, and when the battery state of charge is below 80%, the bus voltage is low and the voltage overshoot tolerance is large, that is, the voltage range allowing the battery pack voltage to rise to the maximum voltage is large, for example, when the battery state of charge SOC is 50%, the voltage overshoot tolerance is 230. Among them, the bus voltage is provided by the relevant detection circuit of the control module.

[0036] Based on this, in order to take into account system efficiency while avoiding voltage overshoot / electromagnetic interference, the present application adds a second driving module 20 on the basis of the original first driving module 10. During the switching process of the power device 200, the control module 30 controls the conduction state of the first driving module 10 and the second driving module 20 through the battery charge state and the preset threshold value, wherein the preset threshold value is the battery charge state preset according to the small voltage overshoot tolerance and the voltage overshoot is very easy to cause. The preset threshold value can be 80%, and there is no restriction on this. That is to say, when the battery charge state is greater than the preset threshold value, the bus voltage is large, so that the difference between the collector-emitter voltage and the maximum voltage is small. At this time, in order to avoid the problem of damaging the power device 200 and increasing electromagnetic interference due to voltage overshoot, a lower gate current driving strength should be used, and the first driving module 10 is controlled to be turned on to drive the power device 200 to operate, and only the first driving module 10 provides a smaller driving force for the gate of the power device 200. The driving current is supplied so that the voltage between the collector and the emitter will not exceed the maximum voltage, thereby avoiding the problem of voltage overcharge / electromagnetic interference. When the battery charge state is less than or equal to the preset threshold, the bus voltage is small, and the difference between the voltage between the collector and the emitter and the maximum voltage is large. A higher gate current driving strength can be used, and the first driving module 10 and the second driving module 20 are controlled to be turned on at the same time to drive the power device 200 to operate. The first driving module 10 and the second driving module 20 jointly provide a higher driving current for the gate of the power device 200 to speed up the switching speed of the power device 200, thereby reducing the switching loss and improving the system efficiency. Therefore, the driving circuit 100 in the present application can avoid the problem of voltage overshoot / electromagnetic interference while taking into account the system efficiency, so that the driving circuit 100 can achieve the optimal effect. In addition, the present application requires fewer components and has low cost, and can improve the system efficiency without changing the over-voltage, under-voltage, over-current, direct-through protection and clamping functions of the gate driving module.

[0037] In addition, the control module 30 can also control the conduction state of the first drive module 10 and the second drive module 20 through the bus voltage and the bus voltage threshold. For example, if the bus voltage is greater than the bus voltage threshold, the first drive module 10 is controlled to be turned on to drive the power device 200 to operate, and only the first drive module 10 provides a smaller drive current to the gate of the power device 200, thereby avoiding the problem of voltage overcharge / electromagnetic interference. If the bus voltage is less than or equal to the bus voltage threshold, the first drive module 10 and the second drive module 20 are controlled to be turned on at the same time to drive the power device 200 to operate, and the first drive module 10 and the second drive module 20 jointly provide a higher drive current to the gate of the power device 200 to speed up the switching speed of the power device 200, thereby reducing switching losses and improving system efficiency.

[0038] According to the drive circuit 100 of the utility model, a second drive module 20 is added on the basis of the original first drive module 10. When it is determined that the voltage overshoot tolerance is small according to the battery charge state, the control module 30 controls the first drive module 10 to provide a driving function alone to reduce the driving current of the power device 200, thereby avoiding the problem of voltage overcharge / electromagnetic interference. When it is determined that the voltage overshoot tolerance is large according to the battery charge state, the control module 30 controls the first drive module 10 and the second drive module 20 to jointly play a driving role to increase the driving current of the power device 200, thereby effectively accelerating the switching speed of the power device 200, reducing the switching loss of the power device 200, and improving the system efficiency.

[0039] In some embodiments, Figure 2 As shown, the first driving module 10 includes: a driver chip 11 and a resistance unit 12, and the driver chip 11 includes a signal processing unit 110, a switch unit 111, a positive power supply terminal VCC, a PWM signal receiving terminal and a driving connection terminal.

[0040] Among them, the positive power supply terminal VCC is used to connect the driving power supply to power the driver chip 11, the driving power supply is a high-voltage side driving power supply, the PWM signal receiving end is connected to the PWM signal output end of the control module 30, the signal processing unit 110 is connected to the PWM signal receiving end, the first end of the switch unit 111 is connected to the positive power supply terminal VCC, the second end of the switch unit 111 is connected to the driving connection end, and the control end of the switch unit 111 is connected to the signal processing unit 110. The first end of the resistor unit 12 is connected to the driving connection end, and the second end of the resistor unit 12 is connected to the gate of the power device 200.

[0041] Specifically, the control module 30 outputs the PWM signal to the PWM signal receiving end through the PWM signal output end, and then enters the signal processing unit 110 from the PWM signal receiving end. The PWM signal is isolated, amplified, and directly interlocked by the signal processing unit 110 and then output to the control end of the switch unit 111 to turn on or off the switch unit 111, thereby causing the circuit where the resistance unit 12 is located to be turned on, so as to drive the power device 200 to be turned on or off.

[0042] In some embodiments, Figure 2 As shown, the PWM signal receiving end includes a PWM-ON signal receiving end PH′, the switch unit 111 includes a first MOS transistor Q1 , and the resistor unit 12 includes a first driving resistor R01 .

[0043] The PWM-ON signal receiving terminal PH' is used to receive the PWM-ON signal, and the driving connection terminal includes a first driving connection terminal OUTH; the first end of the first MOS transistor Q1 is connected to the positive power supply terminal VCC, the second end of the first MOS transistor Q1 is connected to the first driving connection terminal OUTH, and the control end of the first MOS transistor Q1 is connected to the signal processing unit 110; the first end of the first driving resistor R01 is connected to the first driving connection terminal OUTH, and the second end of the first driving resistor R01 is connected to the gate of the power device 200; wherein the signal processing unit 110 controls the positive power supply terminal VCC, the first MOS transistor Q1, the first driving resistor R01 and the gate of the power device 200 to be turned on according to the PWM-ON signal, so as to drive the power device 200 to turn on.

[0044] Exemplarily, when the power device 200 needs to be driven to turn on, the control module 30 sends a PWM_ON signal to the PWM-ON signal receiving terminal PH' of the driver chip 11 through the first PWM signal output terminal PH, wherein the PWM_ON signal is a low-level signal and enters the signal processing unit 110 from the PWM-ON signal receiving terminal. The signal processing unit 110 sends a low-level signal to the gate of the first MOS tube Q1. When the first MOS tube Q1 is a PMOS tube, the first MOS tube Q1 is turned on, thereby controlling the positive power supply terminal VCC, the first MOS tube Q1, the first driving resistor R01 and the gate of the power device 200 to be turned on, so as to provide a driving current for the power device 200. Since the drain of the first MOS tube Q1 outputs a high-level signal to the gate of the power device 200, the power device 200 is driven to turn on.

[0045] In an embodiment, by properly selecting the resistance value of the first driving resistor R01 , the voltage overshoot of the power device 200 can be kept within the maximum voltage range and the voltage overshoot tolerance is appropriate.

[0046] In some embodiments, Figure 2As shown, the second driving module 20 includes: a first driving unit 21 .

[0047] Among them, the first end of the first drive unit 21 is connected to the first control end P1 of the control module 30, the second end of the first drive unit 21 is connected to the first end of the first drive resistor R01 and the first drive connection end OUTH, and the third end of the first drive unit 21 is connected to the second end of the first drive resistor R01 and the gate of the power device 200; wherein, during the conduction process of the power device 200, if the battery charge state is less than or equal to the preset threshold value, the control module 30 controls the first drive unit 21 to be turned on; during the conduction process of the power device 200, if the battery charge state is greater than the preset threshold value, the control module 30 controls the first drive unit 21 to be disconnected.

[0048] Specifically, during the conduction process of the power device 200, if the battery state of charge is less than or equal to the preset threshold value, for example, the battery state of charge is less than or equal to 80%, and the bus voltage is small, then the voltage overshoot tolerance is large, that is, the difference between the collector-emitter voltage and the maximum voltage is large, and a higher gate current drive strength can be used, and the first drive unit 21 of the second drive module 20 is controlled to be turned on, so that the first drive module 10 and the second drive module 20 jointly provide a higher drive current for the gate of the power device 200 to speed up the conduction speed of the power device 200, thereby reducing the turn-on loss and improving the system efficiency; during the conduction process of the power device 200, if the battery state of charge is greater than the preset threshold value, for example, When the battery state of charge is 100% to 80% and the bus voltage is large, the voltage overshoot tolerance is small and the difference between the collector-emitter voltage and the maximum voltage is small. At this time, in order to avoid damage to the power device 200 and increase electromagnetic interference due to voltage overshoot, a lower gate current drive intensity should be used. The control module 30 controls the first drive unit 21 to disconnect, that is, controls the first drive unit 21 to no longer provide a drive current for the gate of the power device 200, but only the first drive module 10 provides a smaller drive current for the gate of the power device 200, so that the collector-emitter voltage does not exceed the maximum voltage, thereby avoiding damage to the power device 200 and generating greater electromagnetic interference due to voltage overshoot.

[0049] In some embodiments, Figure 2 As shown, the first driving unit 21 includes: a first optical coupler U1, a first resistor R1, a second MOS tube Q2, a second resistor R2 and a third resistor R3.

[0050] Among them, the first end of the first optocoupler U1 is used to receive the conduction control signal provided by the first control terminal P1, the second end of the first optocoupler U1 is grounded GND, GND is the low-voltage side ground, the third end of the first optocoupler U1 is connected to the ground terminal GND2 of the driver chip 11, GND2 is the high-voltage side ground, and is used to provide high- and low-voltage side isolation; the first end of the first resistor R1 is connected to the fourth end of the first optocoupler U1; the gate of the second MOS tube Q2 is connected to the second end of the first resistor R1, and the source of the second MOS tube Q2 is connected to the first end of the first drive resistor R01 and the first drive connection terminal OUTH; the first end of the second resistor R2 is connected to the gate of the second MOS tube Q2, The second end of the second resistor R2 is connected to the source of the second MOS transistor Q2; the first end of the third resistor R3 is connected to the drain of the second MOS transistor Q2, and the second end of the third resistor R3 is connected to the second end of the first driving resistor R01 and the gate of the power device 200; wherein, when the first optical coupler U1 is turned on, the loop where the positive power supply terminal VCC, the first driving connection terminal OUTH, the second MOS transistor Q2, the third resistor R3 and the gate of the power device 200 are located is turned on; when the first optical coupler U1 is turned off, the loop where the positive power supply terminal VCC, the first driving connection terminal OUTH, the second MOS transistor Q2, the third resistor R3 and the gate of the power device 200 are located is disconnected. The first resistor R1 and the second resistor R2 are used to set the driving voltage of the second MOS transistor Q2.

[0051] Specifically, during the conduction process of the power device 200, if the battery charge state is less than or equal to the preset threshold value, the bus voltage is small, then the voltage overshoot tolerance is large, that is, the difference between the collector-emitter voltage and the maximum voltage is large, then a higher gate current driving strength can be used, then the control module 30 outputs a conduction control signal to the first optical coupler U1 through the first control terminal P1, wherein the conduction control signal can be a high-level signal to control the first optical coupler U1 of the first drive unit 21 to be continuously turned on, and the low-level signal output by the fourth terminal of the first optical coupler U1 is output to the gate of the second MOS tube Q2 through the first resistor R1, and when the second MOS tube Q2 is a PMOS tube, the second MOS tube Q2 is turned on, based on this, when the first optical coupler U1 is turned on, then The loop consisting of the positive power supply terminal VCC, the first drive connection terminal OUTH, the second MOS transistor Q2, the first resistor R1, the first optical coupler U1 and GND2 is turned on, and correspondingly, the loop consisting of the positive power supply terminal VCC, the first drive connection terminal OUTH, the second MOS transistor Q2, the third resistor R3 and the gate of the power device 200 is turned on, and together with the drive loop consisting of the positive power supply terminal VCC, the first MOS transistor Q1 and the first drive resistor R01, a drive current is provided for the gate of the power device 200. At this time, the equivalent drive resistance R01 / / R3 is reduced, and the gate current of the power device 200 is correspondingly increased, that is, the drive strength is increased, so as to speed up the conduction speed of the power device 200, thereby reducing the turn-on loss and improving the system efficiency. During the conduction process of the power device 200, if the battery charge state is greater than the preset threshold value, the bus voltage is large, and the voltage overshoot tolerance is small, that is, the difference between the collector-emitter voltage and the maximum voltage is small. At this time, in order to avoid damage to the power device 200 due to voltage overshoot and increase in electromagnetic interference, a lower gate current drive strength should be used. The control module 30 outputs a conduction control signal to the first optical coupler U1 through the first control terminal P1. The conduction control signal is a low-level signal to control the first optical coupler U1 to be continuously cut off. When the first optical coupler U1 is cut off, the positive power supply terminal VCC The circuit including the first driving connection terminal OUTH, the second MOS transistor Q2, the third resistor R3 and the gate of the power device 200 is disconnected, that is, the first driving unit 21 is controlled to no longer provide driving current for the gate of the power device 200, but only the driving circuit consisting of the positive power supply terminal VCC, the first MOS transistor Q1 and the first driving resistor R01 provides driving current for the gate of the power device 200, so that the collector-emitter voltage does not exceed the maximum voltage, thereby avoiding the problem of damage to the power device 200 and generation of large electromagnetic interference due to voltage overshoot.

[0052] In an embodiment, the second driving module 20 may include one or more first driving units. In addition, under the condition that there are multiple first driving units, when the battery charge state is less than or equal to the preset threshold, the control module 30 may control some or all of the first driving units to be turned on, so as to increase the driving current of the power device 200, so as to speed up the conduction speed of the power device 200, thereby reducing the turn-on loss and improving the system efficiency.

[0053] In some embodiments, Figure 2 As shown, the driver chip 11 further includes a negative power supply terminal VEE, the PWM signal receiving terminal includes a PWM-OFF signal receiving terminal PL', the switch unit 111 includes a third MOS tube Q3, and the resistor unit 12 includes a second driving resistor R02.

[0054] The PWM-OFF signal receiving terminal PL' is used to receive the PWM-OFF signal, and the driving connection terminal includes a second driving connection terminal OUTL; the first end of the third MOS transistor Q3 is connected to the second driving connection terminal OUTL, and the second end of the third MOS transistor Q3 is connected to the negative power supply terminal VEE, VEE is the negative voltage of the high-voltage side driving power supply, and the control end of the third MOS transistor Q3 is connected to the signal processing unit 110; the first end of the second driving resistor R02 is connected to the second driving connection terminal OUTL, and the second end of the second driving resistor R02 is connected to the gate of the power device 200; wherein the signal processing unit 110 controls the negative power supply terminal VEE, the third MOS transistor Q3, the second driving resistor R02 and the gate of the power device 200 to be turned on according to the PWM-OFF signal, so as to drive the power device 200 to be turned off.

[0055] Exemplarily, when the power device 200 needs to be driven to turn off, the control module 30 sends a PWM-OFF signal to the PWM-OFF signal receiving terminal PL' of the driver chip 11 through the second PWM signal output terminal PL, wherein the PWM-OFF signal is a high-level signal and enters the signal processing unit 110 from the PWM-OFF signal receiving terminal. When the third MOS tube Q3 is an NMOS tube, the signal processing unit 110 sends a high-level signal to the gate of the third MOS tube Q3, and the third MOS tube Q3 is turned on, thereby controlling the negative power supply terminal VEE, the third MOS tube Q3, the second driving resistor R02 and the gate of the power device 200. The loop is turned on, and the drain of the third MOS tube Q3 outputs a low-level signal to the gate of the power device 200 to drive the power device 200 to turn off.

[0056] In an embodiment, by properly selecting the resistance value of the second driving resistor R02 , the voltage overshoot of the power device 200 can be kept within the maximum voltage range and the voltage overshoot tolerance is appropriate.

[0057] In some embodiments, Figure 2 As shown, the second driving module 20 includes: a second driving unit 22 .

[0058] Among them, the first end of the second drive unit 22 is connected to the second control end of the control module 30, the second end of the second drive unit 22 is connected to the first end of the second drive resistor R02 and the second drive connection end OUTL, and the third end of the second drive unit 22 is connected to the second end of the second drive resistor R02 and the gate of the power device 200; wherein, during the shutdown process of the power device 200, if the battery charge state is less than or equal to the preset threshold, the control module 30 controls the second drive unit 22 to be turned on; during the shutdown process of the power device 200, if the battery charge state is greater than the preset threshold, the control module 30 controls the second drive unit 22 to be disconnected.

[0059] Specifically, during the shutdown process of the power device 200, if the battery charge state is less than or equal to the preset threshold, the bus voltage is small, that is, the voltage overshoot tolerance is large, that is, the difference between the collector-emitter voltage and the maximum voltage is large, then a higher gate current drive strength can be used, and the control module 30 controls the second drive unit 22 of the second drive module 20 to turn on, so that the first drive module 10 and the second drive module 20 jointly provide a higher drive current for the gate of the power device 200 to speed up the shutdown speed of the power device 200, thereby reducing the shutdown loss and improving the system efficiency; during the shutdown process of the power device 200, if the battery charge state is greater than the preset threshold, , the bus voltage is larger, then the voltage overshoot tolerance is smaller, that is, the difference between the collector-emitter voltage and the maximum voltage is smaller. At this time, in order to avoid damage to the power device 200 and increase electromagnetic interference due to voltage overshoot, a lower gate current drive intensity should be used. The control module 30 controls the second drive unit 22 to disconnect, that is, the second drive unit 22 is controlled to no longer provide a drive current for the gate of the power device 200, but only the first drive module 10 provides a smaller drive current for the gate of the power device 200, so that the collector-emitter voltage does not exceed the maximum voltage, thereby avoiding damage to the power device 200 and generating greater electromagnetic interference due to voltage overshoot.

[0060] In some embodiments, Figure 2 As shown, the second driving unit 22 includes: a second optical coupler U2, a fourth resistor R4, a fourth MOS transistor Q4, a fifth resistor R5 and a sixth resistor R6.

[0061] Among them, the first end of the second optocoupler U2 is used to receive the conduction control signal provided by the second control end, the second end of the second optocoupler U2 is grounded GND, and the third end of the second optocoupler U2 is connected to the ground terminal GND2 of the driver chip 11, which is used to provide high and low voltage side isolation; the first end of the fourth resistor R4 is connected to the fourth end of the second optocoupler U2; the gate of the fourth MOS tube Q4 is connected to the second end of the fourth resistor R4, and the drain of the fourth MOS tube Q4 is connected to the first end of the second drive resistor R02 and the second drive connection terminal OUTL; the first end of the fifth resistor R5 is connected to the gate of the fourth MOS tube Q4, and the second end of the fifth resistor R5 is connected to The drain of the fourth MOS tube Q4 is connected; the first end of the sixth resistor R6 is connected to the source of the fourth MOS tube Q4, and the second end of the sixth resistor R6 is connected to the second end of the second drive resistor R02 and the gate of the power device 200; wherein, when the second optical coupler U2 is turned on, the loop where the negative power supply terminal VEE, the second drive connection terminal OUTL, the fourth MOS tube Q4, the sixth resistor R6 and the gate of the power device 200 are located is turned on; when the second optical coupler U2 is turned off, the loop where the negative power supply terminal VEE, the second drive connection terminal OUTL, the fourth MOS tube Q4, the sixth resistor R6 and the gate of the power device 200 are located is disconnected. The fourth resistor R4 and the fifth resistor R5 are used to set the driving voltage of the fourth MOS.

[0062] Specifically, during the shutdown process of the power device 200, if the battery charge state is less than or equal to the preset threshold value, the bus voltage is small, the voltage overshoot tolerance is large, that is, the difference between the collector-emitter voltage and the maximum voltage is large, and a higher gate current drive strength can be used. The control module 30 outputs a conduction control signal to the second optical coupler U2 through the second control terminal P2, and the conduction control signal is a high-level signal to control the second optical coupler U2 of the second drive unit 22 to be continuously turned on. The high-level signal output by the fourth end of the second optical coupler U2 is transmitted to the gate of the fourth MOS tube Q4 through the fourth resistor R4. When the fourth MOS tube Q4 is an NMOS tube, the fourth MOS tube Q4 is turned on. When the second optical coupler U2 is turned on, the loop where the negative power supply terminal VEE, the second drive connection terminal OUTL, the fourth MOS tube Q4, the sixth resistor R6 and the gate of the power device 200 are located is turned on, and the driving loop composed of the negative power supply terminal VEE, the third MOS tube Q3, the second driving resistor R02 and the gate of the power device 200 together provides a driving current for the gate of the power device 200. At this time, the equivalent driving resistance R02 / / R6 is reduced, and the gate current of the power device 200 is reduced. The driving strength should be increased to speed up the shutdown speed of the power device 200, thereby reducing the shutdown loss and improving the system efficiency. During the conduction process of the power device 200, if the battery charge state is greater than the preset threshold, in order to avoid damage to the power device 200 due to voltage overshoot and increase electromagnetic interference, a lower gate current driving strength should be used. The control module 30 outputs a conduction control signal to the second optical coupler U2 through the second control terminal. The conduction control signal is a low-level signal to control the second optical coupler U2 to be turned off. When the second optical coupler U2 is turned off, the negative power supply terminal VEE and the second drive terminal VEE are connected to the second optical coupler U2. The loop where the dynamic connection terminal OUTL, the fourth MOS transistor Q4, the sixth resistor R6 and the gate of the power device 200 are located is disconnected, that is, the second driving unit 22 is controlled to no longer provide a driving current for the gate of the power device 200, but only the driving loop composed of the negative power supply terminal VEE, the third MOS transistor Q3, the second driving resistor R02 and the gate of the power device 200 provides a driving current for the gate of the power device 200, so that the collector-emitter voltage does not exceed the maximum voltage, thereby avoiding the problem of damage to the power device 200 and generation of large electromagnetic interference due to voltage overshoot.

[0063] In the embodiment, a suitable driving resistance value needs to be selected to prevent voltage overshoot. When the battery state of charge is between 80% and 20%, the bus voltage changes little. Therefore, the driving resistance values ​​of the third resistor R3 and the sixth resistor R6 of the second driving module 20 and the first driving resistor R01 and the second driving resistor R02 of the first driving module 10 can be selected according to the battery state of charge.

[0064] In an embodiment, the second driving module 20 may include one or more second driving units. In addition, under the condition that there are multiple second driving units, during the shutdown process of the power device 200, when the battery charge state is less than or equal to the preset threshold, the control module 30 may control some or all of the second driving units to be turned on to increase the driving current of the power device 200, thereby accelerating the shutdown speed of the power device 200, thereby reducing the shutdown loss and improving the system efficiency.

[0065] In the embodiment, the optocoupler and MOS tube in the first driving unit 21 and the second driving unit 22 may be replaced by other types of components.

[0066] In some embodiments, the second driving module 20 further includes: a buffer unit. The buffer unit is disposed between the control module 30 and the driving unit. The buffer unit includes a first buffer B1 and a second buffer B2, wherein a first end of the first buffer B1 is connected to a first control end P1 of the control module 30, a second end of the first buffer B1 is connected to a first end of a first optical coupler U1, a first end of the second buffer B2 is connected to a second control end P2 of the control module 30, a second end of the second buffer B2 is connected to a first end of a second optical coupler U2, the first buffer B1 and the second buffer B2 are used to improve the driving capability of the first control end P1 and the second control end P2, and the first buffer B1 and the second buffer B2 can also be used to change the level signal output by the first control end P1 and the second control end P2.

[0067] In addition, the buffer can be omitted when the output current of the first control terminal P1 and the second control terminal P2 is sufficient to control the on and off of the optocoupler.

[0068] In an embodiment, the control module 30 may be a microprocessor of a motor drive system, which is not limited thereto.

[0069] In an embodiment, a push-pull circuit may be added to the output port of the control module 30 to improve the driving capability, wherein the output port may be a PWM signal output terminal, a first control terminal P1 and a second control terminal P2.

[0070] The second aspect of the utility model provides a drive system, such as Figure 4 As shown, the driving system 1000 includes: a power device 200 and a driving circuit 100 of the above embodiment. The driving circuit 100 is used to drive the power device 200 to turn on or off, and the power device 200 can be an IGBT or a MOS tube.

[0071] According to the drive system of the present invention, through the drive circuit 100 of the above embodiment, while avoiding voltage overshoot / electromagnetic interference, it is possible to effectively increase the switching speed of the power device 200, reduce the switching loss of the power device 200, and improve the system efficiency.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0073] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A driving circuit, characterized in that: include: A first driving module, wherein the first driving module is connected to the power device; A second driving module, the second driving module is connected to the power device and the first driving module; A control module, wherein the control module is connected to the first driving module and the second driving module, and the control module is used to control the first driving module to be turned on to drive the power device to operate when the battery state of charge is greater than a preset threshold, and to control the first driving module and the second driving module to be turned on simultaneously to drive the power device to operate when the battery state of charge is less than or equal to the preset threshold.

2. The driving circuit according to claim 1, characterized in that: The first driving module comprises: A driver chip, the driver chip comprising a signal processing unit, a switch unit, a positive power supply terminal, a PWM signal receiving terminal and a driving connection terminal, the positive power supply terminal is used to connect a driving power supply to power the driver chip, the PWM signal receiving terminal is connected to the PWM signal output terminal of the control module, the signal processing unit is connected to the PWM signal receiving terminal, the first terminal of the switch unit is connected to the positive power supply terminal, the second terminal of the switch unit is connected to the driving connection terminal, and the control terminal of the switch unit is connected to the signal processing unit; A resistance unit, wherein a first end of the resistance unit is connected to the driving connection end, and a second end of the resistance unit is connected to the gate of the power device.

3. The driving circuit according to claim 2, characterized in that: The PWM signal receiving end includes a PWM-ON signal receiving end, and the PWM-ON signal receiving end is used to receive a PWM-ON signal. The driving connection end includes a first driving connection end; The switch unit comprises a first MOS transistor, a first end of the first MOS transistor is connected to the positive power supply end, a second end of the first MOS transistor is connected to the first driving connection end, and a control end of the first MOS transistor is connected to the signal processing unit; The resistor unit comprises a first driving resistor, a first end of the first driving resistor is connected to the first driving connection end, and a second end of the first driving resistor is connected to the gate of the power device; The signal processing unit controls the positive power supply terminal, the first MOS tube, the first driving resistor and the circuit where the gate of the power device is located to be turned on according to the PWM-ON signal, so as to drive the power device to be turned on.

4. The driving circuit according to claim 3, characterized in that: The second driving module comprises: A first driving unit, wherein a first end of the first driving unit is connected to a first control end of the control module, a second end of the first driving unit is connected to a first end of the first driving resistor and the first driving connection end, and a third end of the first driving unit is connected to a second end of the first driving resistor and a gate of the power device; Wherein, during the conduction of the power device, if the battery state of charge is less than or equal to a preset threshold, the control module controls the first drive unit to be turned on; during the conduction of the power device, if the battery state of charge is greater than the preset threshold, the control module controls the first drive unit to be turned off.

5. The driving circuit according to claim 4, characterized in that: The first driving unit comprises: a first optical coupler, wherein a first end of the first optical coupler is used to receive a conduction control signal provided by the first control end, a second end of the first optical coupler is grounded, and a third end of the first optical coupler is connected to a ground end of the driver chip; a first resistor, wherein a first end of the first resistor is connected to a fourth end of the first optical coupler; a second MOS transistor, wherein a gate of the second MOS transistor is connected to the second end of the first resistor, and a source of the second MOS transistor is connected to the first end of the first driving resistor and the first driving connection end; a second resistor, wherein a first end of the second resistor is connected to the gate of the second MOS transistor, and a second end of the second resistor is connected to the source of the second MOS transistor; a third resistor, wherein a first end of the third resistor is connected to the drain of the second MOS tube, and a second end of the third resistor is connected to the second end of the first driving resistor and the gate of the power device; Among them, when the first optocoupler is turned on, the positive power supply end, the first drive connection end, the second MOS tube, the third resistor and the loop where the gate of the power device is located are turned on; when the first optocoupler is turned off, the positive power supply end, the first drive connection end, the second MOS tube, the third resistor and the loop where the gate of the power device is located are disconnected.

6. The driving circuit according to any one of claims 2 to 5, characterized in that: The driver chip further includes a negative power supply terminal, the PWM signal receiving terminal includes a PWM-OFF signal receiving terminal, the PWM-OFF signal receiving terminal is used to receive a PWM-OFF signal, and the driving connection terminal includes a second driving connection terminal; The switch unit comprises a third MOS tube, a first end of the third MOS tube is connected to the second driving connection end, a second end of the third MOS tube is connected to the negative power supply end, and a control end of the third MOS tube is connected to the signal processing unit; The resistance unit comprises a second driving resistor, a first end of the second driving resistor is connected to the second driving connection end, and a second end of the second driving resistor is connected to the gate of the power device; The signal processing unit controls the negative power supply terminal, the third MOS tube, the second driving resistor and the loop where the gate of the power device is located to be turned on according to the PWM-OFF signal, so as to drive the power device to be turned off.

7. The driving circuit according to claim 6, characterized in that: The second driving module comprises: a second driving unit, wherein a first end of the second driving unit is connected to a second control end of the control module, a second end of the second driving unit is connected to a first end of the second driving resistor and the second driving connection end, and a third end of the second driving unit is connected to a second end of the second driving resistor and a gate of the power device; Wherein, during the shutdown process of the power device, if the battery state of charge is less than or equal to a preset threshold, the control module controls the second drive unit to turn on; during the shutdown process of the power device, if the battery state of charge is greater than the preset threshold, the control module controls the second drive unit to turn off.

8. The driving circuit according to claim 7, characterized in that: The second driving unit comprises: a second optical coupler, wherein a first end of the second optical coupler is used to receive a conduction control signal provided by the second control end, a second end of the second optical coupler is grounded, and a third end of the second optical coupler is connected to a ground end of the driver chip; a fourth resistor, a first end of the fourth resistor being connected to a fourth end of the second optical coupler; a fourth MOS transistor, wherein a gate of the fourth MOS transistor is connected to the second end of the fourth resistor, and a drain of the fourth MOS transistor is connected to the first end of the second driving resistor and the second driving connection end; a fifth resistor, wherein a first end of the fifth resistor is connected to the gate of the fourth MOS transistor, and a second end of the fifth resistor is connected to the drain of the fourth MOS transistor; a sixth resistor, wherein a first end of the sixth resistor is connected to the source of the fourth MOS tube, and a second end of the sixth resistor is connected to the second end of the second driving resistor and the gate of the power device; Among them, when the second optocoupler is turned on, the negative power supply terminal, the second drive connection terminal, the fourth MOS tube, the sixth resistor and the loop where the gate of the power device is located are turned on; when the second optocoupler is turned off, the negative power supply terminal, the second drive connection terminal, the fourth MOS tube, the sixth resistor and the loop where the gate of the power device is located are disconnected.

9. The driving circuit according to any one of claims 4, 5, 7 and 8, characterized in that: The second driving module further includes: A buffer unit is disposed between the control module and the driving unit.

10. A drive system, characterized in that: include: Power devices; The drive circuit according to any one of claims 1 to 9, wherein the drive circuit is used to drive the power device to turn on or off.

Images