Power tube driving control method and device
阅读说明：本技术 功率管驱动控制方法和装置 (Power tube driving control method and device ) 是由 刘少彬 王涛 高攀 刘宾 孙浩 阮波 柯威威 于 2021-08-27 设计创作，主要内容包括：本发明实施例公开了一种功率管驱动控制方法和装置,控制方法包括：在功率管的栅源电压值从零上升到开通门槛电压值阶段,以第一栅极驱动电流驱动功率管；在功率管的栅源电压值从开通门槛电压值上升到米勒平台电压值阶段,以第二栅极驱动电流驱动功率管；在功率管的栅源电压值维持在米勒平台电压值阶段,以第三栅极驱动电流驱动功率管。本申请解决了现有硬件改进方法难以平衡功率管开通损耗和EMI特性的问题,克服了现有优化控制方法未根据功率管开通的实时状态调整驱动参数的缺陷。本申请实现了根据功率管在开通过程中的实时状态适应性调整驱动参数,使功率管始终处于最优驱动状态,保障电路EMI特性,降低功率管开通损耗,提高功率管效率。(The embodiment of the invention discloses a power tube drive control method and a device, wherein the control method comprises the following steps: driving the power tube by a first grid driving current at the stage that the grid source voltage value of the power tube is increased from zero to a switching-on threshold voltage value; driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the voltage value of the Miller platform; and driving the power tube by a third grid driving current in the stage that the grid source voltage value of the power tube is maintained at the Miller platform voltage value. The method solves the problem that the existing hardware improvement method is difficult to balance the switching-on loss and the EMI characteristic of the power tube, and overcomes the defect that the existing optimization control method does not adjust the driving parameters according to the real-time state of switching-on of the power tube. The method and the device have the advantages that the driving parameters are adjusted according to the real-time state adaptability of the power tube in the opening process, so that the power tube is always in the optimal driving state, the EMI characteristic of a circuit is guaranteed, the opening loss of the power tube is reduced, and the efficiency of the power tube is improved.)
1. A power tube driving control method is characterized by comprising the following steps:
driving the power tube by a first grid driving current at the stage that the grid source voltage value of the power tube is increased from zero to a switching-on threshold voltage value;
driving the power tube by a second grid driving current in a stage that the grid source voltage value of the power tube is increased from a turn-on threshold voltage value to a Miller platform voltage value;
driving the power tube by a third grid driving current in a stage of maintaining the grid source voltage value of the power tube at the voltage value of the Miller platform; wherein the third gate drive current is greater than the second gate drive current.
2. The method of claim 1, further comprising a power tube turn-off process:
in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, driving the power tube by a fourth grid driving current;
driving the power tube by a fifth grid driving current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value;
driving the power tube by a fourth grid driving current at the stage that the grid source voltage value of the power tube is reduced to zero from the opening threshold voltage value; wherein an absolute value of the fourth gate drive current is greater than an absolute value of the fifth gate drive current.
3. The method of claim 2, wherein the third gate drive current is less than the first gate drive current.
4. The method of claim 2, wherein the third gate drive current is equal to the first gate drive current.
5. The method of claim 2, wherein the drain voltage of the power transistor gradually decreases to zero while the gate-source voltage of the power transistor is maintained at the miller plateau voltage.
6. The power tube driving control device is characterized by comprising a switching-on driving module, wherein the switching-on driving module works in the power tube switching-on process and is used for:
driving the power tube by a first grid driving current at the stage that the grid source voltage value of the power tube is increased from zero to a switching-on threshold voltage value;
driving the power tube by a second grid driving current in a stage that the grid source voltage value of the power tube is increased from a turn-on threshold voltage value to a Miller platform voltage value;
when the grid source voltage value of the power tube rises to the voltage value of the Miller platform from the opening threshold voltage value, driving the power tube by a third grid driving current; wherein the third gate current is greater than the second gate drive current.
7. The apparatus of claim 6, further comprising a shutdown driver module operating in a power tube shutdown process to:
in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, driving the power tube by a fourth grid driving current;
driving the power tube by a fifth grid driving current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value;
driving the power tube by a fourth grid driving current at the stage that the grid source voltage value of the power tube is reduced to zero from the opening threshold voltage value; wherein an absolute value of the fourth gate drive current is greater than an absolute value of the fifth gate drive current.
8. The apparatus of claim 6, wherein the third gate drive current is less than the first gate drive current.
9. The apparatus of claim 6, wherein the third gate drive current is equal to the first gate drive current.
10. The apparatus of claim 6, wherein the drain voltage of the power transistor gradually decreases to zero while the gate-source voltage of the power transistor is maintained at the miller plateau voltage.
Technical Field
The embodiment of the invention relates to the technical field of power electronics, in particular to a power tube drive control method and device.
Background
With the continuous development of power electronic technology, technicians in different fields have increasingly stringent requirements on the efficiency of power transistors. Under the condition that system parameters are kept stable, reducing the switching loss of the power tube is an effective way for improving the efficiency of the power tube. The switching loss includes an on-loss and an off-loss.
Since the turn-off process of the power Transistor is opposite to the turn-on process, there are two existing methods for reducing the turn-on loss of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), for example, the turn-on loss of the MOSFET. One aspect is to improve a hardware driving circuit, for example, to adaptively change the resistance of a gate driving resistor. Another aspect is to drive the power tube based on an optimized drive control method.
The existing hardware improvement method is difficult to balance the switching-on loss of the power tube and the EMI characteristic of the circuit, and in addition, the existing optimization control method still has the problems of high switching-on loss and low efficiency of the power tube.
Disclosure of Invention
The embodiment of the invention provides a power tube driving control method and a power tube driving control device, which are used for adaptively adjusting driving parameters according to the real-time state of a power tube in the switching process, so that the power tube is always in the optimal driving state, the EMI (electro-magnetic interference) characteristic of a circuit is guaranteed, the switching loss of the power tube is reduced, and the efficiency of the power tube is improved.
In a first aspect, an embodiment of the present invention provides a power transistor driving control method, including a power transistor turn-on process:
driving the power tube by a first grid driving current at the stage that the grid source voltage value of the power tube is increased from zero to a switching-on threshold voltage value;
driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the voltage value of the Miller platform;
driving the power tube by a third grid driving current in a stage that the grid source voltage value of the power tube is maintained at the voltage value of the Miller platform; and the third gate drive current is larger than the second gate drive current.
Optionally, a power tube turn-off process is further included:
in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, driving the power tube by using a fourth grid driving current;
driving the power tube by a fifth grid drive current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value;
driving the power tube by a fourth grid driving current at the stage that the grid source voltage value of the power tube is reduced to zero from the opening threshold voltage value; wherein an absolute value of the fourth gate driving current is greater than an absolute value of the fifth gate driving current.
Optionally, the third gate drive current is less than the first gate drive current.
Optionally, the third gate drive current is equal to the first gate drive current.
Optionally, the drain voltage of the power tube gradually decreases to zero during the period when the gate-source voltage value of the power tube is maintained at the miller plateau voltage value.
In a second aspect, an embodiment of the present invention further provides a power tube driving control apparatus, including a switching-on driving module, where the switching-on driving module operates in a power tube switching-on process, and is configured to:
driving the power tube by a first grid driving current at the stage that the grid source voltage value of the power tube is increased from zero to a switching-on threshold voltage value;
driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the voltage value of the Miller platform;
when the grid source voltage value of the power tube rises to the voltage value of the Miller platform from the opening threshold voltage value, driving the power tube by a third grid driving current; wherein the third gate current is greater than the second gate drive current.
Optionally, the power tube shutdown system further includes a shutdown driving module, where the shutdown driving module operates in a power tube shutdown process, and is configured to:
in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, driving the power tube by using a fourth grid driving current;
driving the power tube by a fifth grid drive current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value;
driving the power tube by a fourth grid driving current at the stage that the grid source voltage value of the power tube is reduced to zero from the opening threshold voltage value; wherein an absolute value of the fourth gate driving current is greater than an absolute value of the fifth gate driving current.
Optionally, the third gate drive current is less than the first gate drive current.
Optionally, the third gate drive current is equal to the first gate drive current.
Optionally, the drain voltage of the power tube gradually decreases to zero during the period when the gate-source voltage value of the power tube is maintained at the miller plateau voltage value.
According to the technical scheme provided by the embodiment of the invention, the multi-section grid driving current is set in the process of switching on the power tube, and the driving parameters are adaptively selected according to the real-time state of the power tube. Firstly, at the stage that the gate source voltage value of the power tube is raised from zero to a turn-on threshold voltage value, the power tube is driven by a first gate drive current. And secondly, driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the Miller platform voltage value. And finally, driving the power tube by a third grid driving current in a stage that the grid source voltage value of the power tube is maintained at the voltage value of the Miller platform. Based on the method, the problem that the existing drive circuit hardware improvement method is difficult to balance the power tube switching loss and the EMI characteristic is solved, and the defect that the existing power tube drive control method does not adjust the drive parameters according to the real-time state of the power tube in the switching-on process is overcome. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching-on process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching-on loss of the power tube and improving the efficiency of the power tube.
Drawings
Fig. 1 is a flowchart of a power transistor driving control method according to an embodiment of the present invention;
fig. 2 is a flowchart of a power transistor driving control method according to a second embodiment of the present invention;
fig. 3 is a schematic structural diagram of a power transistor driving control apparatus according to a third embodiment of the present invention;
fig. 4 is a circuit diagram of a power transistor driving control apparatus according to a third embodiment of the present invention;
fig. 5 is a schematic control waveform diagram of a power transistor driving control apparatus according to a fourth embodiment of the present invention;
fig. 6 is a schematic control waveform diagram of a power tube driving control device according to a fifth embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad invention. It should be further noted that, for convenience of description, only some structures, not all structures, relating to the embodiments of the present invention are shown in the drawings.
Example one
Fig. 1 is a flowchart of a power tube driving control method according to an embodiment of the present invention, where the present embodiment is applicable to a power tube driving scenario of any device having a driving circuit, and the method may be executed by a power tube driving control apparatus according to an embodiment of the present invention as an execution main body, where the execution main body may be implemented in a software and/or hardware manner. It should be noted that, the power tube driving control method provided in the embodiment of the present invention is exemplarily described by taking a MOSFET as a driving object, that is, the power tube in the embodiment of the present invention is exemplarily referred to as a MOSFET, but the embodiment of the present invention is not limited thereto. For example, the embodiments of the present invention may also be used to drive other types of power transistors such as Insulated Gate Bipolar Transistors (IGBTs). As shown in fig. 1, the method includes a power tube switching-on process, and specifically includes the following steps:
in step 110, the power transistor is driven by the first gate driving current at the stage when the gate-source voltage value of the power transistor rises from zero to the turn-on threshold voltage value.
The specific value of the turn-on threshold voltage value is related to the specific type and model specification of the power tube, which is not limited in the embodiment of the present invention. Illustratively, the turn-on threshold voltage value of a power MOSFET model AON6260 is 1.5V at the minimum, 2V at the classical value and 2.5V at the maximum.
In addition, on the premise of ensuring the stable operation of the power tube, the first gate driving current is used for rapidly increasing the gate source voltage value of the power tube to the turn-on threshold voltage value so as to shorten the turn-on delay time of the power tube. The specific value of the first gate driving current is related to the specific type and model specification of the power transistor, which is not limited in the embodiment of the present invention.
And step 120, driving the power tube by the second gate drive current at the stage when the gate source voltage value of the power tube rises from the opening threshold voltage value to the voltage value of the miller platform.
The specific value of the voltage value of the miller platform is related to the specific type and model specification of the power tube, which is not limited in this embodiment of the present invention.
In the process that the gate source voltage value of the power tube is increased from the opening threshold voltage value to the Miller platform voltage value, the drain current of the power tube starts to increase, and in order to prevent the power tube from being damaged by overlarge reverse recovery current of the body diode, the gate driving current in the process needs to be reduced adaptively. Based on this, the second gate driving current is smaller than the first gate driving current. According to the embodiment, the power tube is driven by the second gate driving current smaller than the first gate driving current, so that the current change rate of device commutation can be reduced, and the EMI (electro-magnetic interference) characteristic of the circuit is further improved. In addition, the specific value of the second gate driving current is related to the specific type and model specification of the power transistor, which is not limited in this embodiment of the present invention.
Step 130, driving the power transistor with a third gate driving current in a stage when the gate-source voltage value of the power transistor is maintained at the miller plateau voltage value.
Optionally, the third gate drive current is less than the first gate drive current.
Optionally, the third gate drive current is equal to the first gate drive current.
Optionally, the drain voltage of the power tube gradually decreases to zero during the period when the gate-source voltage value of the power tube is maintained at the miller plateau voltage value.
And the third gate drive current is larger than the second gate drive current. Based on this, the second gate driving current is smaller than the third gate driving current, and the third gate driving current is smaller than or equal to the first gate driving current.
It should be noted that, in the conventional power tube driving method, it is difficult to increase the gate driving current at the stage when the gate source voltage value of the power tube is maintained at the miller plateau voltage value, so that the miller plateau time period is too long. Therefore, in the miller plateau period, the integral value of the product of the drain current and the drain voltage is correspondingly increased, and the turn-on loss of the power tube is further increased.
In view of this, in the embodiment, by setting the third gate driving current that is greater than the second gate driving current and smaller than the first gate driving current, not only the duration of the miller platform can be shortened, the turn-on process of the power tube is accelerated, the turn-on loss of the power tube is reduced, but also the EMI characteristic of the circuit can be ensured.
According to the embodiment of the invention, a plurality of sections of grid driving currents are set in the process of turning on the power tube, and the driving parameters are adaptively selected according to the real-time state of the power tube. Firstly, at the stage that the gate source voltage value of the power tube is raised from zero to a turn-on threshold voltage value, the power tube is driven by a first gate drive current. And secondly, driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the Miller platform voltage value. And finally, driving the power tube by a third grid driving current in a stage that the grid source voltage value of the power tube is maintained at the voltage value of the Miller platform. Based on the method, the problem that the existing drive circuit hardware improvement method is difficult to balance the power tube switching loss and the EMI characteristic is solved, and the defect that the existing power tube drive control method does not adjust the drive parameters according to the real-time state of the power tube in the switching-on process is overcome. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching-on process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching-on loss of the power tube and improving the efficiency of the power tube.
Example two
Fig. 2 is a flowchart of a power transistor driving control method according to a second embodiment of the present invention. This embodiment is added based on the first embodiment. In this embodiment, optionally, a power tube turn-off process is further included:
and in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, the power tube is driven by the fourth grid driving current.
And driving the power tube by a fifth grid drive current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value.
And at the stage that the gate source voltage value of the power tube is reduced to zero from the opening threshold voltage value, driving the power tube by the fourth gate drive current. Wherein an absolute value of the fourth gate driving current is greater than an absolute value of the fifth gate driving current.
Exemplarily, optionally, the power tube turning-on process may further include:
and driving the power tube by using a sixth grid driving current at the stage that the grid source voltage value of the power tube is increased from the voltage value of the Miller platform to the opening voltage value.
The specific value of the turn-on voltage value is related to the specific type and model specification of the power tube, which is not limited in the embodiment of the present invention. The sixth gate driving current may be greater than or equal to the third gate driving current and less than or equal to the first gate driving current.
It should be noted that, when the sixth gate driving current set in this embodiment is equal to the third gate driving current, the switching-on process of the power transistor can be accelerated while the circuit is ensured to have relatively good EMI characteristics, and the switching-on loss of the power transistor is reduced. When the sixth gate driving current set in this embodiment is equal to the first gate driving current, the turn-on process of the power transistor can be significantly accelerated, and the influence of the miller effect on the power transistor and the turn-on loss of the power transistor can be significantly reduced. Based on this, the specific value of the sixth gate driving current may be adaptively changed according to the driving effect of the power transistor to be obtained, which is not limited in the embodiment of the present invention.
As shown in fig. 2, the method of this embodiment specifically includes the following steps:
in step 210, the power transistor is driven by the first gate driving current at the stage when the gate-source voltage value of the power transistor rises from zero to the turn-on threshold voltage value.
In step 220, the power transistor is driven by the second gate driving current at the stage when the gate-source voltage of the power transistor rises from the turn-on threshold voltage to the miller plateau voltage.
In step 230, the power transistor is driven by the third gate driving current in the stage that the gate-source voltage value of the power transistor is maintained at the miller plateau voltage value.
And 240, driving the power tube by using a sixth gate drive current at the stage that the gate source voltage value of the power tube is increased from the voltage value of the Miller platform to the opening voltage value.
In step 250, in the stage of reducing the gate source voltage value of the power transistor to the miller plateau voltage value and maintaining, the power transistor is driven by the fourth gate driving current.
And step 260, driving the power tube by a fifth grid driving current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value.
In step 270, the power transistor is driven by the fourth gate driving current at the stage when the gate-source voltage of the power transistor drops from the turn-on threshold voltage to zero.
When the gate source voltage value of the power transistor is decreased to the miller plateau voltage value and maintained, the absolute value of the fourth gate driving current may be greater than or equal to the third gate driving current value and less than or equal to the first gate driving current value.
It should be noted that, when the absolute value of the fourth gate driving current set in this embodiment is equal to the third gate driving current value, the current change rate during commutation can be reduced, and while ensuring that the circuit has relatively good EMI characteristics, the turn-off process of the power transistor is accelerated, and the turn-off loss of the power transistor is reduced; when the absolute value of the fourth gate driving current set in this embodiment is equal to the first gate driving current value, the drain voltage of the power transistor can be quickly increased from zero, the turn-off process of the power transistor is remarkably accelerated, and the turn-off loss of the power transistor is remarkably reduced.
Based on this, the specific value of the fourth gate driving current may be adaptively changed according to the intended off-driving effect of the power transistor, which is not limited in the embodiment of the present invention.
In addition, for example, the absolute value of the fifth gate driving current may be equal to the second gate driving current value at a stage when the gate-source voltage value of the power transistor drops from the miller plateau voltage value to the turn-on threshold voltage value.
In order to prevent the overshoot and oscillation of the drain voltage of the power transistor caused by the excessively fast drop speed of the drain current, the gate driving current in the process is required to be adaptively reduced. Based on this, the absolute value of the fourth gate driving current is larger than the absolute value of the fifth gate driving current.
In the embodiment, the power tube is driven by the fifth gate driving current with the absolute value smaller than the fourth gate driving current, so that the change rate of the drain voltage and the current change rate of device commutation can be reduced, and the EMI characteristic of the circuit turn-off process is further improved. In addition, the specific value of the second gate driving current is related to the specific type and model specification of the power transistor, which is not limited in this embodiment of the present invention.
In addition, at the stage that the gate source voltage value of the power tube is reduced from the opening threshold voltage value to zero, on the premise of ensuring the stable work state of the power tube, the fourth gate drive current is used for enabling the gate source voltage value of the power tube to be rapidly reduced from the opening threshold voltage value to zero, so that the turn-off delay time of the power tube is shortened.
The embodiment of the invention sets a plurality of sections of grid driving currents in the switching process of the power tube and carries out adaptive selection of driving parameters according to the real-time state of the power tube. Firstly, at the stage that the gate source voltage value of the power tube is raised from zero to a turn-on threshold voltage value, the power tube is driven by a first gate drive current. And secondly, driving the power tube by a second grid driving current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the Miller platform voltage value. And driving the power tube by using the third grid driving current in the stage that the grid source voltage value of the power tube is maintained at the voltage value of the Miller platform. And thirdly, driving the power tube by using a sixth grid driving current at the stage that the grid source voltage value of the power tube is increased from the Miller platform voltage value to the opening voltage value. And in the second time, in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, the power tube is driven by the fourth grid driving current. And driving the power tube by a fifth grid driving current at the stage that the grid source voltage value of the power tube is reduced from the Miller platform voltage value to the opening threshold voltage value. And finally, driving the power tube by a fourth grid driving current at the stage that the grid source voltage value of the power tube is reduced to zero from the opening threshold voltage value.
Based on the method, the problem that the switching loss and the EMI characteristic of the power tube are difficult to balance by the existing drive circuit hardware improvement method is solved, and the defect that the drive parameters are not adjusted according to the real-time state of the power tube in the switching process by the existing power tube drive control method is overcome. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching loss of the power tube and improving the efficiency of the power tube.
EXAMPLE III
Fig. 3 is a schematic structural diagram of a power transistor driving control apparatus according to a third embodiment of the present invention. As shown in fig. 3, the driving control apparatus 100 includes a power-on driving module 110, where the power-on driving module 110 operates in a power tube power-on process and is configured to:
and driving the power tube by the first grid driving current at the stage that the grid source voltage value of the power tube rises from zero to the opening threshold voltage value.
And driving the power tube by the second grid drive current at the stage that the grid source voltage value of the power tube is increased from the opening threshold voltage value to the Miller platform voltage value.
And when the grid source voltage value of the power tube rises to the voltage value of the Miller platform from the opening threshold voltage value, driving the power tube by the third grid driving current.
Wherein the third gate current is greater than the second gate drive current.
Optionally, the method further includes a shutdown driving module 120, where the shutdown driving module 120 operates in a power tube shutdown process, and is configured to:
and in the stage that the grid source voltage value of the power tube is reduced to the voltage value of the Miller platform and is maintained, the power tube is driven by the fourth grid driving current.
And driving the power tube by a fifth grid drive current at the stage that the grid source voltage value of the power tube is reduced from the voltage value of the Miller platform to the opening threshold voltage value.
And at the stage that the gate source voltage value of the power tube is reduced to zero from the opening threshold voltage value, driving the power tube by the fourth gate drive current.
Wherein an absolute value of the fourth gate driving current is greater than an absolute value of the fifth gate driving current.
Optionally, the third gate drive current is less than the first gate drive current.
Optionally, the third gate drive current is equal to the first gate drive current.
Optionally, the drain voltage of the power tube gradually decreases to zero during the period when the gate-source voltage value of the power tube is maintained at the miller plateau voltage value.
Exemplarily, fig. 4 is a circuit diagram of a power tube driving control device provided in this embodiment. As shown in fig. 4, the power tube drive control apparatus includes: the circuit comprises a photoelectric coupler U1, a current-limiting resistor R3, an NPN triode Q1, a PNP triode Q3, a driving resistor R1, a driving resistor R4, an NPN triode Q2, a PNP triode Q4, a driving resistor R2, a driving resistor R5, a current-limiting resistor R6, a current-limiting resistor R7, a current-limiting resistor R8, a current-limiting resistor R9, a comparator U3C, a comparator U3D, a two-input NAND gate U4, a two-input AND gate U2, an inverter U6, a two-input NAND gate U5, a current-limiting resistor R10 and a current-limiting resistor R11.
It should be noted that the photocoupler U1 forms a strong and weak electric signal isolation and level conversion circuit; a main driving loop is formed by the current limiting resistor R3, the NPN type triode Q1, the PNP type triode Q3, the driving resistor R1 and the driving resistor R4; an auxiliary driving loop is formed by an NPN type triode Q2, a PNP type triode Q4, a driving resistor R2 and a driving resistor R5; the current limiting resistor R6, the current limiting resistor R7, the current limiting resistor R8, the current limiting resistor R9, the comparator U3C, the comparator U3D, the two-input NAND gate U4, the two-input AND gate U2, the inverter U6, the two-input NAND gate U5, the current limiting resistor R10 and the current limiting resistor R11 form a logic control circuit.
Based on the above electronic devices and circuit arrangements, the specific working principle of the power tube driving control device provided in this embodiment is as follows:
the PWM signal IN from the low-voltage side is subjected to strong and weak electric signal isolation and level conversion through a photoelectric isolation device U1, a signal OUT is output, the OUT signal is subjected to current limiting resistance R3 to control the switching action of an NPN type triode Q1 and a PNP type triode Q3 IN a main driving loop, and further the switching control of a rear-stage power semiconductor device is realized, wherein the main driving loop is from Q1/R1 to a Drive loop when the main driving loop is switched on, and the main driving loop is from Drive to R4/Q3 when the main driving loop is switched off.
It should be noted that, in the turn-on and turn-off processes, in order to make the power semiconductor device quickly pass through the miller platform area and reduce the switching loss, an auxiliary control circuit is required to intervene for control, and the driving current is increased in a parallel driving loop manner to accelerate the miller platform stage.
The logic control circuit compares the Drive loop output signal Drive with the power semiconductor device threshold voltage value V _ TH and the Miller platform voltage value V _ plateau in real time by using the comparator U3C/U3D.
In the opening process, when the voltage value of a Drive circuit output signal Drive is smaller than a threshold voltage value V _ TH or larger than a Miller platform voltage value V _ plateau, U4 outputs a high level, an OUT signal and a U4 output signal output a high level V _ QH after passing through U2, Q2 is controlled to be opened, and a Q2/R2 and Q1/R1 form an opening Drive circuit connected in parallel; on the contrary, when the voltage value of the Drive loop output signal Drive is between the threshold voltage value V _ TH and the miller plateau voltage value V _ plateau, the U4 outputs a low level, the OUT signal and the U4 output signal output a low level V _ QH after passing through the U2, the Q2 is controlled to be turned off, and the Q1/R1 forms an independent on Drive loop.
In the turn-off process, when the voltage value of a Drive circuit output signal Drive is smaller than a threshold voltage value V _ TH or larger than a Miller platform voltage value V _ plateau, U4 outputs a high level, an inverted OUT signal and a U4 output signal output a low level V _ QL after passing through U5, Q4 is controlled to be turned on, and a turn-off Drive circuit connected in parallel is formed by Q4/R5 and Q3/R4; on the contrary, when the voltage value of the Drive loop output signal Drive is between the threshold voltage value V _ TH and the miller plateau voltage value V _ plateau, the U4 outputs a low level, the inverted OUT signal and the U4 output signal output a high level V _ QL after passing through the U5, the Q4 is controlled to be turned off, and the Q3/R4 forms an independent turn-off Drive loop.
It should also be noted that, referring to fig. 4, the circuit network IN is the weak point side PWM input signal and GND is the weak point side power ground. VG is a driving power supply, COM is a driving power supply ground, OUT is a PWM signal after isolation and level conversion, Drive is a driving signal sent to a grid electrode of the power semiconductor device, V _ TH is a threshold voltage value of the rear-stage power semiconductor device, and V _ plateau is a Miller platform voltage value of the rear-stage power semiconductor device.
In the embodiment of the invention, in the process of switching on and off the power tube, the on-driving module 110 and the off-driving module 120 are arranged, so that a plurality of sections of grid driving currents are generated, and the driving parameters are adaptively selected according to the real-time state of the power tube. Based on the method, the problem that the switching loss and the EMI characteristic of the power tube are difficult to balance by the existing drive circuit hardware improvement method is solved, and the defect that the drive parameters are not adjusted according to the real-time state of the power tube in the switching process by the existing power tube drive control method is overcome. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching loss of the power tube and improving the efficiency of the power tube.
Example four
Fig. 5 is a schematic diagram of a control waveform of a power transistor driving control apparatus according to a fourth embodiment of the present invention. As shown in FIG. 5, during the turn-on process of the power tube, t0～t1Within a time interval, the grid source voltage value V of the power tubegsRising from 0 to a turn-on threshold voltage value VTHThe current is set as I in the periodG1The first grid drives the current to drive the power tube, so that the grid source voltage value V of the power tubegsQuickly rises to a turn-on threshold voltage value VTHSo as to shorten the turn-on delay time of the power tube.
t1～t2Within a time interval, the grid source voltage value V of the power tubegsFrom the turn-on threshold voltage value VTHVoltage value V rising to Miller platformplateauThe current is set as I in the periodG2Is less than the first gate drive current value IG1The second gate driving current drives the power transistor. The reason for this is that in this process, the drain current I of the power tubeDStarting to rise, in order to prevent reverse recovery current I of the body diodeRRMExcessive damage to the power transistor requires an adaptive reduction of the gate drive current IG。
t2～t3Within a time interval, the grid source voltage value V of the power tubegsMaintained at the Miller plateau voltage value VplateauThe current is set as I in the periodG3Is equal to the first gate drive current value IG1The third gate of (2) drives a current to drive the power transistor. Based on this, the embodiment can shorten the duration of the Miller platform and accelerate the workAnd the switching-on process of the power tube reduces the switching-on loss of the power tube. The reason for this is that: in the traditional power tube driving method, the grid source voltage value V of the power tubegsMaintained at the Miller plateau voltage value VplateauIs difficult to increase the gate drive current IGResulting in a long miller plateau while the drain current I is at the same timeDAnd the drain voltage VDThe integral value of the product is correspondingly increased, and the turn-on loss of the power tube is further increased.
t3～t4Within a time interval, the grid source voltage value V of the power tubegsFrom the Miller plateau voltage value VplateauRising to the value of the turn-on voltage VGThe current is set as I in the periodG6Is equal to the first gate drive current value IG1The sixth grid drives the current to drive the power tube so as to accelerate the switching-on process of the power tube, reduce the influence of the Miller effect on the power tube and reduce the switching-on loss of the power tube.
During the turn-off process of the power tube, t5～t7Within a time interval, the grid source voltage value V of the power tubegsDropping and maintaining at the Miller plateau voltage value VplateauThe absolute value of the period equals to the first gate drive current value IG1The fourth grid drives the current to drive the power tube, so that the drain voltage V of the power tubeDThe rapid rise from 0 remarkably quickens the turn-off process of the power tube and remarkably reduces the turn-off loss of the power tube.
t7～t8Within a time interval, the grid source voltage value V of the power tubegsFrom the Miller plateau voltage value VplateauDown to the turn-on threshold voltage value VTHThe absolute value of the period equals to the second gate drive current value IG2The fifth gate of (2) drives the power transistor with the current. The reason for this is that in this process, the drain current I of the power tubeDStart to fall in order to prevent drain current IDPower tube drain voltage V caused by too fast falling speedDOvershoot and ringing phenomena, the need to adaptively reduce the gate drive current I in the processG。
t8～t9Within a time interval, the grid source voltage value V of the power tubegsFrom the turn-on threshold voltage value VTHDropping to 0, and driving the power tube with the fourth gate drive current in the period to make the gate source voltage value V of the power tubegsQuickly starting up threshold voltage value VTHAnd decreases to zero to shorten the turn-off delay time of the power tube.
The embodiment of the invention sets a plurality of sections of grid driving currents in the switching process of the power tube and carries out adaptive selection of driving parameters according to the real-time state of the power tube. Wherein, t0～t1Within a time interval, the current is taken as IG1The first grid drives the current to drive the power tube; t is t1～t2Within a time interval, the current is taken as IG2Is less than the first gate drive current value IG1The second grid drives the current to drive the power tube; t is t2～t3Within a time interval, the current is taken as IG3Is equal to the first gate drive current value IG1The third grid drives the current to drive the power tube; t is t3～t4Within a time interval, the current is taken as IG6Is equal to the first gate drive current value IG1The sixth grid drives the current to drive the power tube; t is t5～t7In a time period, the absolute value is equal to the first gate drive current value IG1The fourth grid drives the current to drive the power tube; t is t7～t8In a time period, the absolute value is equal to the second gate drive current value IG2The fifth grid drives the current to drive the power tube; t is t8～t9And in the time period, driving the power tube by using the fourth grid driving current.
Based on the method, the problem that the switching loss and the EMI characteristic of the power tube are difficult to balance by the existing drive circuit hardware improvement method is solved, and the defect that the drive parameters are not adjusted according to the real-time state of the power tube in the switching process by the existing power tube drive control method is overcome. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching loss of the power tube and improving the efficiency of the power tube.
EXAMPLE five
Fig. 6 is a schematic control waveform diagram of a power tube driving control device according to a fifth embodiment of the present invention. As shown in FIG. 6, during the turn-on process of the power tube, t0～t1Within a time interval, the grid source voltage value V of the power tubegsRising from 0 to a turn-on threshold voltage value VTHThe current is set as I in the periodG1The first grid drives the current to drive the power tube, so that the grid source voltage V of the power tubegsThe value rises rapidly to the opening threshold voltage value VTHSo as to shorten the turn-on delay time of the power tube.
t1～t2Within a time interval, the grid source voltage value V of the power tubegsFrom the turn-on threshold voltage value VTHVoltage value V rising to Miller platformplateauThe current is set as I in the periodG2Is less than the first gate drive current value IG1The second gate driving current drives the power transistor. The reason for this is that in this process, the drain current I of the power tubeDStarting to rise, in order to prevent reverse recovery current I of the body diodeRRMExcessive damage to the power transistor requires an adaptive reduction of the gate drive current IG。
t2～t3Within a time interval, the grid source voltage value V of the power tubegsMaintained at the Miller plateau voltage value VplateauThe current is set as I in the periodG3Is less than the first gate drive current value IG1The third gate of (2) drives a current to drive the power transistor. Therefore, the embodiment can shorten the duration of the Miller platform, accelerate the switching-on process of the power tube, reduce the switching-on loss of the power tube and ensure the EMI characteristic of the circuit.
t3～t4Within a time interval, the grid source voltage value V of the power tubegsFrom the Miller plateau voltage value VplateauRising to the value of the turn-on voltage VGThe current is set as I in the periodG6Is equal to the first gate drive current value IG1The sixth grid drives the current to drive the power tube so as to accelerate the switching-on process of the power tube and reduce the Miller effect on the power tubeInfluence and reduce the turn-on loss of the power tube.
During the turn-off process of the power tube, t5～t7Within a time interval, the grid source voltage value V of the power tubegsDropping and maintaining at the Miller plateau voltage value VplateauThe absolute value of the period equals to the first gate drive current value IG1The fourth grid drives the current to drive the power tube, so that the drain voltage V of the power tubeDThe rapid rise from 0 remarkably quickens the turn-off process of the power tube and remarkably reduces the turn-off loss of the power tube.
t7～t8Within a time interval, the grid source voltage value V of the power tubegsFrom the Miller plateau voltage value VplateauDown to the turn-on threshold voltage value VTHThe absolute value of the period equals to the second gate drive current value IG2The fifth gate of (2) drives the power transistor with the current. The reason for this is that in this process, the drain current I of the power tubeDStart to fall in order to prevent drain current IDPower tube drain voltage V caused by too fast falling speedDOvershoot and ringing phenomena, the need to adaptively reduce the gate drive current I in the processG。
t8～t9Within a time interval, the grid source voltage value V of the power tubegsFrom the turn-on threshold voltage value VTHDropping to 0, and driving the power tube with the fourth gate drive current in the period to make the gate source voltage value V of the power tubegsQuickly starting up threshold voltage value VTHAnd decreases to zero to shorten the turn-off delay time of the power tube.
In the embodiment of the invention, the multi-section grid driving current is adaptively and selectively set according to the real-time state of the power tube in the switching process of the power tube. Wherein, t0～t1Within a time interval, the current is taken as IG1The first grid drives the current to drive the power tube; t is t1～t2Within a time interval, the current is taken as IG2Is less than the first gate drive current value IG1The second grid drives the current to drive the power tube; t is t2～t3Within a time interval, the current is taken as IG3Is smaller than the first gate driverDynamic current value IG1The third grid drives the current to drive the power tube; t is t3～t4Within a time interval, the current is taken as IG6Is equal to the first gate drive current value IG1The sixth grid drives the current to drive the power tube; t is t5～t7In a time period, the absolute value is equal to the first gate drive current value IG1The fourth grid drives the current to drive the power tube; t is t7～t8In a time period, the absolute value is equal to the second gate drive current value IG2The fifth grid drives the current to drive the power tube; t is t8～t9And in the time period, driving the power tube by using the fourth grid driving current.
Therefore, the embodiment of the application solves the problem that the existing drive circuit hardware improvement method is difficult to balance the switching loss and the EMI characteristic of the power tube, and overcomes the defect that the existing power tube drive control method does not adjust the drive parameters according to the real-time state of the power tube in the switching process. The embodiment of the invention realizes the adaptive adjustment of the driving parameters according to the real-time state of the power tube in the switching process, thereby not only ensuring the power tube to be always in the optimal driving state and the EMI characteristic of the circuit, but also reducing the switching loss of the power tube and improving the efficiency of the power tube.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
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