CN110086454B - Overload control device of power module - Google Patents
Overload control device of power module Download PDFInfo
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- CN110086454B CN110086454B CN201910294629.4A CN201910294629A CN110086454B CN 110086454 B CN110086454 B CN 110086454B CN 201910294629 A CN201910294629 A CN 201910294629A CN 110086454 B CN110086454 B CN 110086454B
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- overload control
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/14—Modifications for compensating variations of physical values, e.g. of temperature
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K2017/0806—Modifications for protecting switching circuit against overcurrent or overvoltage against excessive temperature
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0081—Power supply means, e.g. to the switch driver
Abstract
The invention discloses an overload control device of a power module, which comprises a pulse width comparison circuit and an overload control circuit; wherein: the input end of the pulse width comparison circuit is connected with the output end of a driving circuit used for controlling the on-state of a switching tube in the power module, and the output end of the pulse width comparison circuit is connected with the input end of the overload control circuit; the pulse width comparison circuit is used for generating an overload signal when the pulse width of the driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit is used for determining that the power module is in an overload state after receiving the overload signal and generating a control signal for reducing the temperature of the power module at an output end. Therefore, the power module can be detected whether to work in an overload state or not only by acquiring the pulse width of the driving signal without the help of a temperature sensor. Compare in a plurality of temperature sensor, the circuit structure cost of this application is lower, and the overload condition of the power module who detects is more accurate.
Description
Technical Field
The present invention relates to the field of power module overload detection, and in particular, to an overload control apparatus for a power module.
Background
At present, when a power module normally works, the loss of a power device (such as a switching tube) contained in the power module can cause the heating of the power device, when the heating value exceeds a certain value, natural air cooling cannot meet the heat dissipation requirement, and a refrigeration system is required to be additionally arranged to force the power device to cool down, so that the normal work of the power module is ensured. In the prior art, a plurality of temperature sensors are usually correspondingly mounted on a plurality of radiators where power devices are located, and the operation of a refrigeration system is controlled through the temperature change of the radiators detected by the temperature sensors, so as to meet the heat dissipation requirements of the power devices. However, the cost of the plurality of temperature sensors is high, and some power devices enable a signal with large dv/dt variation to exist on the radiator, and a detection signal of the temperature sensor is easily interfered by a noise end (the noise end is defined as the noise end with large dv/dt variation), so that the detection is inaccurate, and the control of the refrigeration system is influenced; in addition, in a low-temperature environment, the power module is already operated to an overload state (at this time, the refrigeration system is required to force the power device to cool down), but due to the influence of the ambient temperature, the temperature of the heat sink detected by the temperature sensor is not the actual temperature of the power device, and the detection result at this time is likely that the power module has not yet reached the overload state, so that the detection accuracy is reduced.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide an overload control device of a power module, which can detect whether the power module works in an overload state or not only by acquiring the pulse width of a driving signal without a temperature sensor, has lower circuit structure cost and more accurate overload condition of the detected power module.
In order to solve the above technical problem, the present invention provides an overload control apparatus for a power module, which includes a pulse width comparison circuit and an overload control circuit; wherein:
the input end of the pulse width comparison circuit is connected with the output end of a driving circuit for controlling the on-state of a switching tube in the power module, and the output end of the pulse width comparison circuit is connected with the input end of the overload control circuit;
the pulse width comparison circuit is used for generating an overload signal when the pulse width of the driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit is used for determining that the power module is in an overload state after receiving the overload signal, and generating a control signal for reducing the temperature of the power module at an output end.
Preferably, the pulse width comparison circuit includes an integration circuit and a first comparator; wherein:
the input end of the integrating circuit is used as the input end of the pulse width comparison circuit, the output end of the integrating circuit is connected with the input negative end of the first comparator, the input positive end of the first comparator is connected with a preset first reference voltage, and the output end of the first comparator is used as the output end of the pulse width comparison circuit; and the time constant of the integration circuit is greater than a preset time constant.
Preferably, the integration circuit comprises a first resistor and a first capacitor; wherein:
the first end of the first resistor is used as the input end of the integrating circuit, the second end of the first resistor is connected with the first end of the first capacitor, the common end of the first resistor is used as the output end of the integrating circuit, and the second end of the first capacitor is grounded.
Preferably, the pulse width comparison circuit further comprises:
and the filter circuit is connected with the input positive end of the first comparator at the first end and grounded at the second end and is used for filtering the interference signal input by the input positive end of the first comparator.
Preferably, the filter circuit comprises a second resistor and a second capacitor; wherein:
the first end of the second resistor is connected with the first end of the second capacitor, the common end of the second resistor is used as the first end of the filter circuit, the second end of the second resistor is connected with the second end of the second capacitor, and the common end of the second resistor is used as the second end of the filter circuit.
Preferably, the overload control circuit includes a second comparator, a pull-up resistor, a third resistor, and a first dc power supply; wherein:
the input negative end of the second comparator is used as the input end of the overload control circuit, the input positive end of the second comparator is connected with a preset second reference voltage, the output end of the second comparator is respectively connected with the first end of the pull-up resistor and the first end of the third resistor, the second end of the pull-up resistor is connected with the output end of the first direct current power supply, and the second end of the third resistor is used as the output end of the overload control circuit.
Preferably, the overload control apparatus further includes:
and the time delay circuit is used for delaying the output signal of the first comparator for a preset time and then inputting the output signal into the second comparator.
Preferably, the delay circuit includes a fourth resistor, a third capacitor, a diode and a second dc power supply; wherein:
the first end of the fourth resistor is respectively connected with the first end of the third capacitor and the anode of the diode, the common end of the fourth resistor is used as the input end and the output end of the delay circuit, the second end of the fourth resistor is respectively connected with the cathode of the diode and the output end of the second direct current power supply, and the second end of the third capacitor is grounded.
Preferably, the overload control apparatus further includes:
and the current limiting circuit is connected with the output end of the first comparator at the first end and connected with the input end of the delay circuit at the second end.
Preferably, the overload control apparatus further includes a pulse width grading circuit; wherein:
the input end of the pulse width grading circuit is connected with the output end of the driving circuit, and the output end of the pulse width grading circuit is connected with the input end of the overload control circuit;
the pulse width grading circuit is used for determining the current pulse width grade of the driving signal according to a preset multi-stage pulse width interval when the pulse width of the driving signal is greater than the preset pulse width threshold;
correspondingly, the overload control circuit is specifically configured to preset a corresponding relationship between a pulse width level of the driving signal and a cooling level of the power module; and after receiving the overload signal, determining that the power module is in an overload state, determining a target cooling grade corresponding to the current pulse width grade according to the corresponding relation, and generating a cooling control signal corresponding to the target cooling grade at an output end.
The invention provides an overload control device of a power module, which comprises a pulse width comparison circuit and an overload control circuit; wherein: the input end of the pulse width comparison circuit is connected with the output end of a driving circuit for controlling the switching-on state of a switching tube in the power module, and the output end of the pulse width comparison circuit is connected with the input end of the overload control circuit; the pulse width comparison circuit is used for generating an overload signal when the pulse width of the driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit is used for determining that the power module is in an overload state after receiving the overload signal and generating a control signal for reducing the temperature of the power module at an output end.
According to the power module and the power module control method, the load capacity of the power module is determined by considering that the pulse width of the driving signal output by the driving circuit corresponding to the power module represents the load capacity of the power module (the larger the pulse width value is, the larger the load capacity of the power module is), and the load capacity of the power module determines the power consumption of the power module, namely the heat productivity of the power module. It is thus clear that, compare in a plurality of temperature sensor, the circuit structure cost of this application is lower, and the overload condition of the power module that detects is more accurate.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an overload control apparatus for a power module according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another overload control apparatus for a power module according to an embodiment of the present invention.
Detailed Description
The core of the invention is to provide an overload control device of a power module, which can detect whether the power module works in an overload state or not only by acquiring the pulse width of a driving signal without a temperature sensor, and has lower circuit structure cost and more accurate overload condition of the detected power module.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an overload control apparatus of a power module according to an embodiment of the present invention.
The overload control apparatus of the power module includes: a pulse width comparison circuit 1 and an overload control circuit 2; wherein:
the input end of the pulse width comparison circuit 1 is connected with the output end of a driving circuit for controlling the on-state of a switching tube in the power module, and the output end of the pulse width comparison circuit 1 is connected with the input end of the overload control circuit 2;
the pulse width comparison circuit 1 is used for generating an overload signal when the pulse width of a driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit 2 is arranged to determine that the power module is in an overload state upon receiving the overload signal and to generate a control signal at an output for reducing the temperature of the power module.
It should be noted that the preset of the present application is set in advance, and only needs to be set once, and the reset is not needed unless the modification is needed according to the actual situation.
Specifically, the pulse width of a driving signal (i.e., a driving square wave) output by a driving circuit (controlling the on state of a switching tube in the power module) corresponding to the power module may represent the load capacity of the power module, and the load capacity of the power module determines the power consumption of the power module, i.e., determines the heat generation amount of the power module. When the pulse width value of the driving signal is larger, the larger the load capacity of the power module is, the larger the power consumption of the power module is, and the more the heat generation amount of the power module is.
Because the natural air cooling cannot meet the heat dissipation requirement when the heat value of the power module exceeds the allowable heat value (i.e., the power module operates in an overload state), the temperature of the power device in the power module is generally required to be reduced to ensure the normal operation of the power module. Therefore, the pulse width value is set in advance (the setting principle is that when the pulse width of the driving signal output by the driving circuit is larger than the set pulse width value, the heat productivity of the power module exceeds the allowed heating value, the power module works in an overload state, and when the pulse width of the driving signal output by the driving circuit is not larger than the set pulse width value, the heat productivity of the power module does not exceed the allowed heating value, and the power module is not overloaded).
Based on this, the overload control device of this application includes pulse width comparison circuit 1 and overload control circuit 2, and its theory of operation is: the pulse width comparison circuit 1 compares the pulse width of the driving signal output by the driving circuit with a set pulse width value, if the pulse width of the driving signal is greater than the set pulse width value, the power module works in an overload state, an overload signal is generated and output to the overload control circuit 2, so that the overload control circuit 2 generates a control signal for reducing the temperature of the power module at the output end of the overload control circuit after receiving the overload signal, and correspondingly inputs the control signal to a controlled device, so as to reduce the temperature of the power device by using the controlled device; if the pulse width of the driving signal is not larger than the set pulse width value, it is indicated that the power module is not overloaded, at this time, natural air cooling meets the heat dissipation requirement, the power device does not need to be cooled, an overload signal is not generated, and the overload control circuit 2 does not play a role in overload control at this time.
Therefore, the overload control device for determining the carrying capacity of the power module by detecting the driving pulse width so as to reduce the temperature of the power device when the power module is overloaded is provided, a temperature sensor is not needed, the circuit structure cost is lower, and the control is more accurate.
In addition, the controlled device for reducing the temperature of the power module in the application can select a refrigeration device (such as a fan), and the specific control mode can be as follows: when the power module works in an overload state, the overload control circuit 2 controls the refrigerating device to operate; when the power module is not overloaded, the overload control circuit 2 controls the refrigerating device to stop running. Of course, the controlled device of the present application may also select some devices that affect the load capacity of the power module (for example, a motor, a relay, etc., and the load capacity of the power module is reduced by reducing the driving pulse width when the power module is overloaded by controlling the switching signals of the motor, the relay, etc.), and the present application is not limited thereto.
The invention provides an overload control device of a power module, which comprises a pulse width comparison circuit and an overload control circuit; wherein: the input end of the pulse width comparison circuit is connected with the output end of a driving circuit used for controlling the on-state of a switching tube in the power module, and the output end of the pulse width comparison circuit is connected with the input end of the overload control circuit; the pulse width comparison circuit is used for generating an overload signal when the pulse width of the driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit is configured to determine that the power module is in an overload state upon receiving the overload signal and to generate a control signal at an output for reducing a temperature of the power module.
The power module determines the power consumption of the power module, namely determines the heat productivity of the power module, considering that the pulse width of the driving signal output by the driving circuit corresponding to the power module represents the load capacity of the power module (the larger the pulse width value is, the larger the load capacity of the power module is), so that whether the power module works in an overload state can be detected only by acquiring the pulse width of the driving signal without a temperature sensor. It is thus clear that, compare in a plurality of temperature sensor, the circuit structure cost of this application is lower, and the overload condition of the power module that detects is more accurate.
Referring to fig. 2, fig. 2 is a schematic structural diagram of another overload control apparatus for a power module according to an embodiment of the present invention. The overload control device is based on the above embodiment:
as an alternative embodiment, the pulse width comparison circuit 1 includes an integration circuit and a first comparator D1; wherein:
the input end of the integrating circuit is used as the input end of the pulse width comparison circuit 1, the output end of the integrating circuit is connected with the input negative end of the first comparator D1, the input positive end of the first comparator D1 is connected with a preset first reference voltage, and the output end of the first comparator D1 is used as the output end of the pulse width comparison circuit 1; the time constant of the integrating circuit is larger than the preset time constant.
Specifically, the pulse width comparison circuit 1 of the present application includes an integrating circuit and a first comparator D1, and its operating principle is:
the integration circuit of the present application integrates a drive signal output by a drive circuit. It should be noted that the time constant of the integration circuit should be greater than a certain time constant, so that the waveform output by the integration circuit tends to be smooth, and the subsequent circuits can realize smooth control. That is, when the time constant of the integration circuit is large, the output waveform is relatively gentle, and at this time, the output waveform of the integration circuit can be approximately regarded as a dc component corresponding to the driving signal. As the pulse width of the drive signal is larger, the voltage value of the waveform output by the integration circuit is larger, and thus the voltage value input to the input negative terminal of the first comparator D1 is larger.
The input positive end of the first comparator D1 inputs a set first reference voltage Vref 1 (the setting principle is that when the voltage value of the waveform output by the integrating circuit is larger than the first reference voltage, the pulse width of the driving signal is considered to be larger than the set pulse width value, namely the heat productivity of the power module exceeds the allowed heat value, at the moment, the power device needs to be cooled, when the voltage value of the waveform output by the integrating circuit is not larger than the first reference voltage, the pulse width of the driving signal is considered to be not larger than the set pulse width value, at the moment, the power device does not need to be cooled), and when the voltage value of the waveform output by the integrating circuit is not larger than the set first reference voltage, the first comparator D1 outputs a high level; when the voltage value of the waveform output by the integrating circuit is greater than the set first reference voltage, the first comparator D1 outputs a low level. Therefore, the overload control circuit 2 does not control the controlled device when the first comparator D1 outputs a high level; when the first comparator D1 outputs a low level, the controlled device is controlled to cool down the power device.
As an alternative embodiment, the integrating circuit includes a first resistor R1 and a first capacitor C1; wherein:
the first end of the first resistor R1 is used as the input end of the integrating circuit, the second end of the first resistor R1 is connected with the first end of the first capacitor C1, the common end thereof is used as the output end of the integrating circuit, and the second end of the first capacitor C1 is grounded.
Specifically, the integration circuit of the present application includes a first resistor R1 and a first capacitor C1. It should be noted that the values of the first resistor R1 and the first capacitor C1 should ensure that the time constant of the integration circuit is greater than a certain time constant.
As an alternative embodiment, the pulse width comparison circuit 1 further includes:
and the filter circuit is connected with the input positive end of the first comparator D1 at the first end and grounded at the second end and is used for filtering the interference signal input by the input positive end of the first comparator D1.
Further, the pulse width comparison circuit 1 of the present application further includes a filter circuit for filtering an interference signal input by the input positive terminal of the first comparator D1, so that the stability of the first reference voltage signal input by the first comparator D1 is improved, and further, the accuracy and reliability of the pulse width comparison circuit 1 are improved.
As an alternative embodiment, the filter circuit includes a second resistor R2 and a second capacitor C2; wherein:
a first end of the second resistor R2 is connected to a first end of the second capacitor C2, a common end of the second resistor R2 is used as a first end of the filter circuit, a second end of the second resistor R2 is connected to a second end of the second capacitor C2, and a common end of the second resistor R2 is used as a second end of the filter circuit.
Specifically, the filter circuit of the present application includes a second resistor R2 and a second capacitor C2, that is, an RC filter circuit is used to filter an interference signal input to the input positive terminal of the first comparator D1. Of course, the filter circuit of the present application may also be another type of filter circuit, and the present application is not limited thereto.
As an alternative embodiment, the overload control circuit 2 includes a second comparator D2, a pull-up resistor R, a third resistor R3, and a first dc power supply; wherein:
the input negative end of the second comparator D2 serves as the input end of the overload control circuit 2, the input positive end of the second comparator D2 is connected to a preset second reference voltage, the output end of the second comparator D2 is connected to the first end of the pull-up resistor R and the first end of the third resistor R3 respectively, the second end of the pull-up resistor R is connected to the output end of the first direct current power supply, and the second end of the third resistor R3 serves as the output end of the overload control circuit 2.
Specifically, the overload control circuit 2 of the present application includes a second comparator D2, a pull-up resistor R, a third resistor R3, and a first dc power supply, and its operating principle is:
the input positive end of the second comparator D2 inputs the set second reference voltage Vref 2, when the first comparator D1 outputs a high level, the second comparator D2 outputs a low level, and the overload control circuit 2 does not play a role in overload control; when the first comparator D1 outputs a low level, the second comparator D2 outputs a high level (the output voltage of the second comparator D2 is pulled up to the output voltage VCC of the first dc power supply by the pull-up resistor R, and then a control signal is obtained after current limiting by the third resistor R3), and the control signal controls the controlled device, so that the controlled device enters a state of reducing the temperature of the power device.
As an optional embodiment, the overload control apparatus further includes:
and the delay circuit is used for delaying the output signal of the first comparator D1 for a preset time and then inputting the output signal into the second comparator D2.
Further, the overload control apparatus of the present application further includes a delay circuit, which can delay the output signal of the first comparator D1 for a certain time and input the delayed signal to the second comparator D2, so as to provide a sufficient response time for the controlled apparatus.
As an optional embodiment, the delay circuit includes a fourth resistor R4, a third capacitor C3, a diode D, and a second dc power supply; wherein:
a first end of the fourth resistor R4 is connected to the first end of the third capacitor C3 and the anode of the diode D, respectively, a common end of the fourth resistor R4 is used as an input end and an output end of the delay circuit, a second end of the fourth resistor R4 is connected to the cathode of the diode D and the output end of the second dc power supply, and a second end of the third capacitor C3 is grounded.
Specifically, the delay circuit comprises a fourth resistor R4, a third capacitor C3, a diode D and a second direct-current power supply, wherein the values of the fourth resistor R4 and the third capacitor C3 determine the delay time of the delay circuit; the diode D can realize the quick discharge of the third capacitor C3, thereby realizing the time delay control by cooperating together.
As an optional embodiment, the overload control apparatus further comprises:
and the current limiting circuit is connected with the output end of the first comparator D1 at the first end and connected with the input end of the delay circuit at the second end.
Furthermore, the control device of the application also comprises a current limiting circuit which is used for limiting the current value on a line between the first comparator D1 and the delay circuit, so that the safety and the reliability of the overload control device are improved. Specifically, the current limiting circuit may be selected from, but not limited to, the current limiting resistor R5, and the application is not limited thereto.
As an alternative embodiment, the overload control apparatus further includes a pulse width grading circuit; wherein:
the input end of the pulse width grading circuit is connected with the output end of the driving circuit, and the output end of the pulse width grading circuit is connected with the input end of the overload control circuit 2;
the pulse width grading circuit is used for determining the current pulse width grade of the driving signal according to a preset multi-stage pulse width interval when the pulse width of the driving signal is greater than a preset pulse width threshold value;
correspondingly, the overload control circuit 2 is specifically configured to preset a corresponding relationship between a pulse width level of the driving signal and a cooling level of the power module; and after receiving the overload signal, determining that the power module is in an overload state, determining a target cooling grade corresponding to the current pulse width grade according to the corresponding relation, and generating a cooling control signal corresponding to the target cooling grade at an output end.
Further, the overload control device of the present application further includes a pulse width classification circuit, and its operating principle is:
under the condition that the pulse width of the driving signal is larger than the preset pulse width threshold value, the overload control circuit 2 controls the controlled device to cool the power device. It can be understood that, the larger the pulse width value of the driving signal is, the more serious the heat generation of the power module is, and for the power module with the relatively serious heat generation condition, the better the cooling effect of the corresponding controlled device is. Based on the above, the pulse width of the driving signal is classified, and the cooling grade of the power module is correspondingly controlled according to the grade of the pulse width of the driving signal.
Specifically, the pulse width classification circuit of the present application presets a plurality of pulse width intervals, such as a pulse width value A0-a pulse width value A1 (primary pulse width interval), a pulse width value A1-a pulse width value A2 (secondary pulse width interval), a pulse width value A2-a pulse width value A3 (tertiary pulse width interval) … …, and here, may be set as: the larger the pulse width value of the interval is, the higher the level of the pulse width interval is, and the lowest pulse width value of the multi-level pulse width interval is not less than the corresponding lowest pulse width value of the controlled device in the controlled state. Then, the pulse width grading circuit determines the current pulse width grade of the driving signal according to the current pulse width of the driving signal (for example, if the current pulse width value of the driving signal is between the pulse width value A0 and the pulse width value A1, the current pulse width grade of the driving signal is one grade), and sends the current pulse width grade of the driving signal to the overload control circuit 2.
The overload control circuit 2 presets the corresponding relationship between the pulse width level of the driving signal and the cooling level of the power module (the higher the pulse width level of the driving signal is, the more serious the heating of the power module is, the higher the cooling level of the power module is, the better the cooling effect of the controlled device on the heating power device is, that is, the higher the cooling level of the controlled device on the heating power device is, it can be understood that the higher the pulse width level of the driving signal is, the higher the cooling level of the corresponding power module is, so that after receiving the current pulse width level of the driving signal, the overload control circuit 2 can determine the target cooling level of the power module according to the corresponding relationship between the pulse width level and the cooling level, and generate a cooling control signal corresponding to the target cooling level at its output end, so as to control the cooling level of the controlled device (for example, when the controlled device is a fan, control the high and low gears of the fan), thereby more reasonably controlling the operation of the controlled device and ensuring the normal operation of the power module.
More specifically, the pulse width grading circuit of the present application may include a plurality of comparators for setting different voltage reference values to implement pulse width grading of the driving signal, so that the overload control circuit 2 controls the cooling degree of the controlled device according to the high and low levels output by the plurality of comparators. Alternatively, the pulse width grading circuit of the present application may calculate the pulse width value of the driving signal to determine the pulse width grade to which the pulse width of the driving signal belongs. The present application is not particularly limited with respect to the specific implementation of the pulse width grading circuit.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. The overload control device of a power module is characterized by comprising a pulse width comparison circuit and an overload control circuit; wherein:
the input end of the pulse width comparison circuit is connected with the output end of a driving circuit for controlling the on-state of a switching tube in the power module, and the output end of the pulse width comparison circuit is connected with the input end of the overload control circuit;
the pulse width comparison circuit is used for generating an overload signal when the pulse width of the driving signal output by the driving circuit is greater than a preset pulse width threshold value; the overload control circuit is used for determining that the power module is in an overload state after receiving the overload signal and generating a control signal for reducing the temperature of the power module at an output end;
the pulse width comparison circuit comprises an integrating circuit and a first comparator; wherein:
the input end of the integrating circuit is used as the input end of the pulse width comparison circuit, the output end of the integrating circuit is connected with the input negative end of the first comparator, the input positive end of the first comparator is connected with a preset first reference voltage, and the output end of the first comparator is used as the output end of the pulse width comparison circuit; and the time constant of the integration circuit is greater than a preset time constant.
2. The overload control apparatus for a power module according to claim 1, wherein the integration circuit includes a first resistor and a first capacitor; wherein:
the first end of the first resistor is used as the input end of the integrating circuit, the second end of the first resistor is connected with the first end of the first capacitor, the common end of the first resistor is used as the output end of the integrating circuit, and the second end of the first capacitor is grounded.
3. The overload control apparatus for a power module according to claim 2, wherein the pulse width comparison circuit further comprises:
and the filter circuit is connected with the input positive end of the first comparator at the first end and grounded at the second end and is used for filtering the interference signal input by the input positive end of the first comparator.
4. The overload control apparatus for a power module according to claim 3, wherein the filter circuit includes a second resistor and a second capacitor; wherein:
the first end of the second resistor is connected with the first end of the second capacitor, the common end of the second resistor is used as the first end of the filter circuit, the second end of the second resistor is connected with the second end of the second capacitor, and the common end of the second resistor is used as the second end of the filter circuit.
5. The overload control apparatus for a power module according to claim 1, wherein the overload control circuit includes a second comparator, a pull-up resistor, a third resistor, and a first dc power supply; wherein:
the input negative end of the second comparator is used as the input end of the overload control circuit, the input positive end of the second comparator is connected with a preset second reference voltage, the output end of the second comparator is respectively connected with the first end of the pull-up resistor and the first end of the third resistor, the second end of the pull-up resistor is connected with the output end of the first direct current power supply, and the second end of the third resistor is used as the output end of the overload control circuit.
6. The overload control apparatus for a power module according to claim 5, wherein the overload control apparatus further comprises:
and the time delay circuit is used for delaying the output signal of the first comparator for a preset time and then inputting the output signal into the second comparator.
7. The overload control apparatus for a power module according to claim 6, wherein the delay circuit includes a fourth resistor, a third capacitor, a diode, and a second dc power supply; wherein:
the first end of the fourth resistor is respectively connected with the first end of the third capacitor and the anode of the diode, the common end of the fourth resistor is used as the input end and the output end of the delay circuit, the second end of the fourth resistor is respectively connected with the cathode of the diode and the output end of the second direct current power supply, and the second end of the third capacitor is grounded.
8. The overload control apparatus for a power module according to claim 7, wherein the overload control apparatus further comprises:
and the current limiting circuit is connected with the output end of the first comparator at the first end and connected with the input end of the delay circuit at the second end.
9. The overload control apparatus for a power module according to any one of claims 1 to 8, wherein the overload control apparatus further comprises a pulse width classification circuit; wherein:
the input end of the pulse width grading circuit is connected with the output end of the driving circuit, and the output end of the pulse width grading circuit is connected with the input end of the overload control circuit;
the pulse width grading circuit is used for determining the current pulse width grade of the driving signal according to a preset multi-stage pulse width interval when the pulse width of the driving signal is greater than the preset pulse width threshold;
correspondingly, the overload control circuit is specifically configured to preset a correspondence between a pulse width level of the driving signal and a cooling level of the power module; and after receiving the overload signal, determining that the power module is in an overload state, determining a target cooling grade corresponding to the current pulse width grade according to the corresponding relation, and generating a cooling control signal corresponding to the target cooling grade at an output end.
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| IT1248382B (en) * | 1991-05-09 | 1995-01-11 | Cons Ric Microelettronica | PROTECTION CIRCUIT AGAINST INCREASED OUTPUT CURRENT FOR AN INTEGRATED CIRCUIT INCLUDING A POWER DEVICE THAT DRIVES A RESONANT LOAD CONNECTED TO A POWER SUPPLY |
| JP2000105612A (en) * | 1998-09-28 | 2000-04-11 | Unisia Jecs Corp | Power control unit for electric equipment |
| JP2004273660A (en) * | 2003-03-07 | 2004-09-30 | Renesas Technology Corp | Semiconductor integrated circuit |
| JP4818971B2 (en) * | 2007-03-29 | 2011-11-16 | 三菱電機株式会社 | Temperature detection circuit |
| CN104660229A (en) * | 2015-02-04 | 2015-05-27 | 深圳市甲木科技有限公司 | PWM modulation device and output power limiting circuit thereof |
| CN106330151B (en) * | 2015-07-01 | 2019-07-26 | 佛山市顺德区美的电热电器制造有限公司 | The driving circuit of IGBT pipe |
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