IGBT drive plate aging test circuit
Technical Field
The utility model relates to a IGBT drive plate test field, in particular to IGBT drive plate aging testing circuit.
Background
The IGBT drive board is a board-level circuit product consisting of an IGBT drive chip, a drive auxiliary power supply, a drive peripheral circuit and a plug connector, is used as an important intermediate link between a control system and a switch device, and is used for receiving control instructions of the control system, transmitting control commands, ensuring that the switch device IGBT executes correct switching actions, protecting the switch device and feeding back the working state of the IGBT, and is deeply loved by electrical engineers.
However, the IGBT driver board is often used in a high-power converter, the operating performance of the IGBT driver board is inevitably adversely affected after a period of use, the operating life and reliability of the IGBT driver board directly affect the operation of the converter, and if the aging characteristics of the IGBT driver board can be accurately obtained, the IGBT driver board has a great help meaning for improving the reliability of the IGBT driver board. In other words, the aging performance of the IGBT driver board directly affects the operational reliability of the IGBT driver board, and therefore, the aging test of the IGBT driver board is particularly important.
At present, the aging test circuit of the IGBT drive board adopts a power supply to provide drive energy support for the drive board, a pulse generator provides fixed-frequency pulses for the drive board, and the aging test of the IGBT drive board is completed through an indicator lamp arranged on the drive board. Specifically, the input signal with fixed frequency and the power supply are directly connected with the IGBT drive board through a cable, so that the IGBT drive board is in a load working state, and if an abnormal state occurs, the indicator lamp gives an indication. Although the circuit structure of the aging test circuit is very simple, the aging test circuit has at least two fatal defects:
1. no dynamic ageing function. In actual operation, the IGBT drive board works under pulses with different frequencies to a great extent, and the test condition cannot fully simulate the actual working condition and expose the condition of early failure.
2. And no overcurrent and overvoltage protection. The test circuit only plays a role in prompting, and the drive board cannot be protected when the circuit fails, so that the drive board is damaged.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a IGBT drive plate aging testing circuit, this IGBT drive plate aging testing circuit are applicable to the ageing characteristic of test IGBT drive plate, compare traditional IGBT drive plate aging testing circuit and increase dynamic ageing function and overcurrent and overvoltage protection function.
In order to realize above arbitrary utility model purpose, this technical scheme provides an IGBT drive plate aging testing circuit, includes at least: the protection device comprises a control component, a driving plate, a protection component and a power supply; one end of the control assembly is connected with the drive plate, and intermittent variable frequency pulses are generated in the control assembly and are transmitted to the drive plate; a current sampling circuit and a power supply switching circuit are arranged in the protection assembly, one end of the current sampling circuit is connected with the drive plate and used for collecting the real-time aging current of the drive plate, and the other end of the current sampling circuit is connected with the control assembly and used for transmitting the real-time aging current of the drive plate to the control assembly; one end of the power supply switching circuit is connected with the control assembly, one end of the power supply switching circuit is connected with the power supply, the other end of the power supply switching circuit is connected with the drive board, and the power supply circuit between the power supply and the drive board is switched on or switched off according to the instruction of the control assembly.
In some embodiments, the protection component comprises a first switch tube, a second switch tube, an amplifier and a circuit sampling resistor, the amplifier amplifies the voltage across the resistor and transmits the voltage to the control component, the first switch tube and the second switch tube are connected in a shunt way and controlled by the control component, and the conduction state of the first switch tube and the second switch tube is switched under the control of the control component.
In some embodiments, one end of the first switch tube is connected to the control component, one end is connected to the power supply, the other end is grounded, and one end of the driving plate is also grounded; one end of the second switch tube is connected with the first switch tube, the other end of the second switch tube is connected with the power supply, and the other end of the second switch tube is connected with the driving board; the circuit sampling resistor is arranged between the second switch tube and the power supply, the input end of the amplifier is respectively arranged on two side edges of the circuit sampling resistor, and the output end of the amplifier is connected to the control component.
In some embodiments, the control assembly includes a controller, wherein the controller is a programmable mcu.
In some embodiments, the pulse output chip pin of the controller is connected to the driver board through the MC14504 level shift chip.
In some embodiments, the first switch tube is connected to a first control pin of the controller, and the amplifier is connected to a voltage input pin of the controller.
In some embodiments, the first switch tube and the second switch tube are mos switch tubes.
In some embodiments, the first switch tube is connected to the power source.
In some embodiments, when the controller detects that the driving board is in a normal aging state, the first control pin outputs a 0 level, the second switch tube is turned on, and the first switch tube is turned off.
In some embodiments, when the controller finds that the driving board has an over-current and over-voltage phenomenon through the voltage at two ends of the circuit sampling resistor, the first control pin outputs a high level, the first switch tube is turned on, and the second switch tube is turned off.
Compared with the prior art, the technical scheme has the following characteristics and beneficial effects:
1. and a dynamic aging function is added, the output waveform is controlled by the mcu, and discontinuous/variable-frequency pulses are formed, so that the aging of the IGBT drive board is closer to the actual working condition, and the aging test result is more accurate.
2. And an overcurrent and overvoltage protection function is added, so that the IGBT driving board is protected from being damaged when the IGBT driving board breaks down in the aging process.
Drawings
Fig. 1 is a schematic structural diagram of an IGBT driver board aging test circuit according to an embodiment of the present disclosure.
Fig. 2 is a detailed structural schematic diagram of an IGBT driver board aging test circuit according to an embodiment of the present disclosure.
In the figure: 10-a control component, 11-a controller, 12-a level conversion chip, 20-a driving board, 30-a protection component, 31-a first switch tube, 32-a second switch tube, 33-an amplifier, 34-a circuit sampling resistor and 40-a power supply.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art all belong to the protection scope of the present invention.
It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in a generic and descriptive sense only and not for purposes of limitation, as the terms are used in the description to indicate that the referenced device or element must have the specified orientation, be constructed and operated in the specified orientation, and not for the purposes of limitation.
It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.
As shown in fig. 1 and fig. 2, the present technical solution provides an IGBT driver board aging test circuit, which at least includes: the device comprises a control assembly (10), a driving plate (20), a protection assembly (30) and a power supply (40), wherein one end of the control assembly (10) is connected with the driving plate (20), and intermittent variable frequency pulses are generated in the control assembly (10) and are transmitted to the driving plate (20); a current sampling circuit and a power supply switching circuit are arranged in the protection assembly (30), one end of the current sampling circuit is connected with the drive plate (20) and collects the real-time aging current of the drive plate, and the other end of the current sampling circuit is connected with the control assembly (10) and transmits the real-time aging current of the drive plate (20) to the control assembly (10); one end of the power supply switching circuit is connected with the control assembly (10), one end of the power supply switching circuit is connected with the power supply (40), the other end of the power supply switching circuit is connected with the driving board (20), and the power supply circuit between the power supply (40) and the driving board (20) is switched on or switched off according to the instruction of the control assembly (10).
Namely, the control assembly (10) provides intermittent and variable-frequency pulses for the drive plate (20), the protection assembly (30) collects real-time aging current of the drive plate (20), and if the real-time aging current of the drive plate (20) is judged to exceed a set threshold value in the control assembly (10), the protection assembly (30) is controlled to switch a power supply conducting route so as to stop supplying power to the drive plate (20), and the effect of protecting the drive plate (20) is achieved.
Specifically, in the technical scheme, the protection component (30) comprises a first switch tube (31), a second switch tube (32), an amplifier (33) and a circuit sampling resistor (34), wherein one end of the first switch tube (31) is connected with the control component (10), one end of the first switch tube is connected with the power supply (40), the other end of the first switch tube is grounded, and one end of the driving plate (20) is also grounded; one end of the second switch tube (32) is connected with the first switch tube (31), the other end of the second switch tube is connected with the power supply (40), and the other end of the second switch tube is connected with the driving plate (20); the circuit sampling resistor (34) is arranged between the second switch tube (32) and the power supply (40), the input end of the amplifier (33) is respectively arranged on two side edges of the circuit sampling resistor (34), and the output end of the amplifier (33) is connected to the control component (10).
In other words, the amplifier (33) amplifies the voltage across the resistor (34) and transmits the voltage to the control component (10), and the control component (10) judges whether the driving plate (20) is in an overvoltage and overcurrent state or not. The first switch tube (31) and the second switch tube (32) are connected in a shunt way and controlled by the control assembly (10), and the conducting state of the first switch tube (31) and the conducting state of the second switch tube (32) are switched under the control of the control assembly (10) so as to control whether the power supply (40) supplies power to the driving plate (20).
In addition, a collector pull-up resistor is connected between the first switch tube (31) and the power supply (40), and the collector pull-up resistor and the first switch tube (31) form an inverter.
In the technical scheme, the control assembly (10) comprises a controller (11), wherein the controller (11) is implemented as a programmable mcu and can generate a variable frequency pulse signal, and a pulse output chip pin of the controller (11) is connected to the driving plate (20) through a level conversion chip (12) so as to transmit the variable frequency pulse generated by the controller (11) to the driving plate (20) to simulate the actual working condition of the driving plate (20). In the technical scheme, the level conversion chip (12) is an MC14504 level conversion chip.
The first switch tube (31) and the second switch tube (32) are selected to be mos switch tubes, and can be switched to be in a conducting state and a non-conducting state under the control of the controller (11).
The first switch tube (31) is connected to a first control pin of the controller (11), and the amplifier (33) is connected to a voltage input pin of the controller (11).
The aging current real-time sampling principle of the IGBT drive board aging test circuit is as follows:
the circuit sampling resistor (34) is connected to the driving plate (20) through the second switch tube (32), current in the driving plate (20) is converted into voltage through the circuit sampling resistor (34), the amplifier (33) obtains and amplifies voltage at two ends of the circuit sampling resistor (34), namely current conditions in the driving plate (20) are obtained, and a voltage input pin of the controller (11) inputs the voltage at the moment and judges whether the driving plate (20) is overcurrent or not.
The protection principle of the IGBT drive board aging test circuit is as follows:
one end of the first switch tube (31) is connected to a first control pin of the controller (11), the other two ends of the first switch tube are respectively connected with the power supply (40) and the ground, and the low-level end of the driving plate (20) is connected to one end of the first switch tube (31) which is grounded; one end of the second switch tube (33) is connected with the power supply (40), one end of the second switch tube is connected with one end of the first switch tube (31) connected with the power supply (40), and the other end of the second switch tube is connected with the high-level end of the driving plate (20).
When the controller (11) detects that the driving board (20) is in a normal aging state, namely, no overcurrent and overvoltage state exists, the first control pin outputs 0 level, the second switch tube (32) is conducted, the first switch tube (31) is cut off, the current of the power supply (40) sequentially passes through the circuit sampling resistor (34) and the second switch tube (32) and is input into the driving board (20), and at the moment, the driving board (20) continues to work under the action of frequency conversion pulses.
When the controller (11) finds that the driving board (20) has an overcurrent and overvoltage phenomenon through the voltage at the two ends of the circuit sampling resistor (34), the first control pin outputs a high level, the first switch tube (31) is switched on, the second switch tube (32) is switched off, and the current of the power supply (40) cannot be input into the driving board (20), so that the circuit protection of the driving board (20) is realized.
In addition, in the embodiment of the present invention, the voltage of the power source (40) is controlled to be 15v, and of course, any voltage larger than 0v may be used.
The present invention is not limited to the above-mentioned preferred embodiments, and any other products in various forms can be obtained by the teaching of the present invention, but any changes in the shape or structure thereof, which have the same or similar technical solutions as the present invention, fall within the protection scope of the present invention.