CN212572065U - Power module protection circuit and consumer - Google Patents
Power module protection circuit and consumer Download PDFInfo
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- CN212572065U CN212572065U CN202021731039.8U CN202021731039U CN212572065U CN 212572065 U CN212572065 U CN 212572065U CN 202021731039 U CN202021731039 U CN 202021731039U CN 212572065 U CN212572065 U CN 212572065U
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Abstract
The application discloses power module protection circuit and consumer. In the power module protection circuit, the current value of the current to be detected is converted into a voltage signal through the current sensor, the voltage is compared with the reference voltage output by the DA conversion module in the MCU, when the voltage obtained by the current conversion to be detected is greater than the reference voltage, the comparator outputs a control signal to the intelligent power module IPM, so that the intelligent power module IPM outputs a fault signal to the MCU, and the MCU is enabled to close U, V, W three-phase signal output to realize the protection of the circuit. Because the output voltage value of the DA conversion module in the MCU can be adjusted through a program, the MCU outputs reference voltages with different voltage values, different requirements on the reference voltages under different scenes are met, and the universality of the protection circuit is improved.
Description
Technical Field
The application relates to the technical field of circuit protection, in particular to a power module protection circuit and electric equipment.
Background
In the industry of variable frequency air conditioners, a demagnetization protection circuit of an Intelligent Power Module is a common circuit, a sampled output voltage of current is compared by a comparator to output a protection signal to the Intelligent Power Module (IPM) to realize protection, the response of protection action is fast, and a motor can be reliably protected.
The traditional demagnetization protection circuit presets a reference voltage U1And when the current sampling output voltage exceeds a preset value, a protection signal is output. However, the preset value is obtained by dividing the fixed voltage, and cannot be adjusted after being set. However, because the frequency converters bear different currents, the current protection values of the demagnetization protection circuits of the intelligent power module currents are different, which results in that motors of different specifications need to have frequency converters with demagnetization protection values of different specifications correspondingly. Therefore, the traditional protection circuit has poor universality and cannot meet the requirements of different scenes.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides a power module protection circuit and electric equipment, and is used for solving the problem of poor universality of the power module protection circuit.
In a first aspect, an embodiment of the present application provides a power module protection circuit, including: the intelligent power module IPM, the micro control unit MCU, the current sensor and the comparator;
the current sensor is connected with a first input end of the comparator and used for converting the collected current to be detected into a voltage signal and inputting the voltage signal to the comparator;
a DA conversion module in the MCU is connected with a second input end of the comparator and used for inputting the reference voltage to the comparator;
the output end of the comparator is connected with a voltage detection terminal Cin of the IPM, and the comparator is used for outputting a control signal to the IPM when the voltage converted by the current to be detected is greater than the reference voltage;
a fault signal output terminal F0 of the IPM is connected with the MCU, and the IPM outputs a fault signal to the MCU when receiving the control signal;
the U, V, W three-phase signal output end of the MCU is respectively connected with the U, V, W three-phase signal input end of the IPM, and the MCU closes the U, V, W three-phase signal output end of the MCU after receiving a fault signal.
In a possible implementation manner, the MCU is further connected to a temperature sensor, and receives the current temperature detected by the temperature sensor;
and the MCU determines the voltage value output by the DA conversion module in the MCU according to the current temperature.
In a possible implementation manner, the power module protection circuit further includes a clamping circuit;
the current sensor is connected with the first input end of the comparator through the clamping circuit.
In one possible implementation, the clamping circuit includes a first diode and a second diode;
the cathode of the first diode is connected with a power supply, the anode of the first diode is connected with the cathode of the second diode, and the anode of the second diode is connected with the ground;
and the anode of the first diode is respectively connected with the current sensor and the first input end of the comparator.
In a possible implementation manner, the power module protection circuit further includes a voltage divider circuit;
and the DA conversion module in the MCU is connected with the second input end of the comparator through the voltage division circuit.
In one possible implementation, the voltage divider circuit includes a first resistor and a second resistor;
the first end of the first resistor is connected with a DA conversion module in the MCU, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the ground;
and the second end of the first resistor is used as the output end of the voltage division circuit and is connected with the second input end of the comparator.
In a possible implementation manner, the power module protection circuit further includes a third resistor and a first capacitor;
a first end of the third resistor is connected with the output end of the comparator, and a second end of the third resistor is connected with the voltage detection terminal Cin of the IPM;
the first end of the first capacitor is connected with the second end of the third resistor, and the second end of the first capacitor is connected with the ground.
In a second aspect, an embodiment of the present application provides an electric device, including the power module protection circuit according to any implementation manner of the first aspect.
In one possible implementation, the electrical device is an air conditioner.
In one possible implementation, the air conditioner includes a temperature sensor provided on a compressor;
and the temperature sensor is connected with the MCU in the power module protection circuit.
In the power module protection circuit provided by the embodiment of the application, the current value of the current to be detected is converted into a voltage signal through the current sensor, the voltage is compared with the reference voltage output by the DA conversion module in the MCU, and when the voltage obtained by the current conversion to be detected is greater than the reference voltage, the comparator outputs a control signal to the intelligent power module IPM, so that the IPM outputs a fault signal to the MCU, and the MCU is enabled to close U, V, W three-phase signal output to realize the protection of the circuit. Because the output voltage value of the DA conversion module in the MCU can be adjusted through a program, the MCU outputs reference voltages with different voltage values, different requirements on the reference voltages under different scenes are met, and the universality of the protection circuit is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of a power module protection circuit according to an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of a clamp circuit according to an embodiment of the present disclosure;
fig. 3 is a second schematic diagram of a power module protection circuit according to an embodiment of the present disclosure.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.
In order to solve the problem that a conventional power module protection circuit is poor in universality, the embodiment of the application provides a power module protection circuit and electric equipment so as to meet circuit protection requirements in different scenes.
Referring to fig. 1, a schematic structural diagram of a power module protection circuit provided in an embodiment of the present application is shown, where the power module protection circuit includes: smart power module 101, micro control unit 102, current sensor 103 and comparator 104.
Specifically, the current sensor 103 is disposed on the line to be detected, and is connected to a first input terminal of the comparator 104. The current sensor 103 is used for converting the current on the line to be detected into a voltage signal (i.e. a voltage to be detected) and inputting the voltage signal to the comparator 104.
An output end of a digital-to-analog conversion (DA conversion) module in the micro control unit 102 is connected to a second input end of the comparator 104, and is used for inputting the reference voltage output by the DA conversion module to the comparator 104.
The comparator 104 is configured to compare the voltage value of the voltage to be measured with the voltage value of the reference voltage, and output a control signal when the voltage value of the voltage to be measured is greater than the voltage value of the reference voltage. The output terminal of the comparator 104 is connected to the power supply detection terminal Cin of the smart power module 101, that is, a control signal is input to the smart power module 101.
The fault signal output terminal F0 of the smart power module 101 is connected to the micro control unit 102. The smart power module 101 outputs a fault signal to the micro control unit 102 after receiving the control signal input from the comparator 104.
The U, V, W three-phase signal (i.e., U-phase control signal, V-phase control signal, W-phase control signal) output terminals of the mcu 102 are connected to the U, V, W three-phase signal input terminals of the smart power module 101. The mcu 102, upon receiving the fault signal, shuts down its U, V, W three-phase signal output.
The intelligent power module is a power switch device, and has the advantages of high current density, low saturation voltage and high voltage resistance of a GTR (high power transistor), and the advantages of high input impedance, high switching frequency and low driving power of an MOSFET (metal-oxide-semiconductor field effect transistor). The built-in driving and protecting circuit of the intelligent power module enables a system hardware circuit to be simple and reliable, shortens system development time and improves self-protecting capability under faults. The intelligent power module has the advantages of multiple protection functions, strong anti-interference capability, no need of adopting anti-static measures, small size and the like, and is more and more widely applied to the field of power electronics.
A Micro Control Unit (MCU), also called a single chip microcomputer or a single chip microcomputer, is to appropriately reduce the frequency and specification of a central processing Unit, and integrate peripheral interfaces such as a memory, a counter, and a/D conversion, and a Liquid Crystal Display (LCD) driving circuit on a single chip to form a chip-level Computer, which is used for different applications, such as mobile phone, Personal Computer (PC) periphery, remote controller, and other various devices.
The voltage output by the DA conversion module in the micro control unit 102 is used as a reference voltage, and if the current to be detected obtained by converting the current to be detected is greater than the reference voltage, that is, the current to be detected is greater than a preset reference current, the circuit needs to be protected. The micro control unit 102 can input different voltage digital quantities to the DA conversion module through the programmed program, so that the DA conversion module can output voltage signals with different voltage values, and therefore, the same hardware protection circuit can be adopted, different requirements for reference current under different scenes can be met through software control, the universality of the power module protection circuit is enhanced, different hardware circuits do not need to be designed according to different scenes, and the complexity of circuit design is reduced.
Furthermore, different temperatures may result in different demands on the reference voltage (or reference current) even under the same scenario. In order to further meet different requirements for reference voltage (or reference current) at different temperatures, the reference voltage can be changed along with the temperature change, so that the maximum power can be output at different temperatures. Specifically, a fitting curve of the current and the temperature may be predetermined, the current value may be converted into a voltage value, voltage values corresponding to different temperatures may be determined, and the correspondence may be stored in the micro control unit 102. For example, assume a temperature T1The demagnetization circuit of the motor is I1Then, the output voltage U corresponding to the DA conversion module in the mcu 1021＝(I1-. DELTA.I)/R, where. DELTA.I represents a predetermined current deviation value. The micro control unit 102 is further connected to the temperature sensor, receives the current temperature detected by the temperature sensor, determines a voltage value corresponding to the current temperature according to a pre-stored correspondence relationship, and inputs the voltage value corresponding to the current temperature to the DA conversion module in the micro control unit 102, so that the DA conversion module sets a reference voltage of the corresponding voltage value, and the comparator 104 compares the voltage to be detected with the reference voltageThen the obtained product is obtained.
If a conventional protection circuit with fixed reference voltage is still adopted, the reference voltage cannot change along with the temperature change, and in order to ensure the safety of the circuit, the reference voltage needs to be set to be a small value, even if the current value does not have a problem at the current temperature, because the reference voltage is fixed (namely, the reference current is fixed), the circuit can be protected as long as the current exceeds the preset reference current, and the maximum power output cannot be realized. After the above embodiments of the present application are adopted, the reference voltage will change along with the temperature change, so that the circuit can be ensured to output with the maximum power.
Optionally, the power module protection circuit may further include a clamp circuit, and the current sensor 103 is connected to the first input terminal of the comparator 104 through the clamp circuit. The clamp circuit can stabilize the voltage to be measured obtained by conversion of the current sensor 103 within a preset range, and damage to components and parts due to large fluctuation of the voltage to be measured is avoided.
Fig. 2 exemplarily shows a schematic structure of a clamp circuit, which includes a first diode D1 and a second diode D2 as shown. The cathode of the first diode D1 is connected with a power supply VCC, and the anode is connected with the cathode of the second diode D2; the anode of the second diode D2 is connected to ground. The anode of the first diode D1 is connected to the current sensor 103 and the first input terminal of the comparator 104. When the voltage value to be measured output by the current sensor 103 is greater than VCC + the turn-on voltage of the first diode D1, the first diode D1 is turned on, and when the voltage value to be measured is less than the turn-on voltage of the negative second diode D2, the second diode D2 is turned on, so that the voltage value of the point of the positive electrode of the first diode D1 is clamped within the preset range.
In some embodiments, the power module protection circuit may further include a voltage divider circuit, through which the DA conversion module in the micro control unit 102 is connected to the second input terminal of the comparator 104, that is, the voltage output by the DA conversion module is divided, and the divided voltage is input to the comparator 104 as a reference voltage.
In a specific embodiment, the power module protection circuit provided by the present application may be as shown in fig. 3, and includes: smart power module 101, micro control unit 102, current sensor 103, comparator 104, clamp circuit 105, voltage divider circuit 106, and temperature sensor 107.
Specifically, a P line and an N line of a circuit to be protected are respectively connected to the intelligent power module 101, a current sensor 103 is arranged on the P line, current on the P line is collected and converted into a voltage signal, and the voltage signal passes through the clamp circuit 105, so that a voltage value is clamped in a preset range. The voltage to be measured passing through the clamp circuit 105 is input to a first input terminal, i.e., "-" terminal, of the comparator 104.
The mcu 102 outputs a preset voltage through the DA conversion module, and the preset voltage is input to the comparator 104 as a reference voltage through the voltage divider circuit 105. The voltage dividing circuit 105 includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 is connected to the DA conversion module, a second end of the first resistor R2 is connected to a first end of the second resistor R2, a second end of the second resistor R2 is connected to ground, and a second end of the first resistor R1 is used as an output end of the voltage dividing circuit 105 and is connected to a second input end, i.e., a "+" end, of the comparator 104.
The micro control unit 102 is further connected to the temperature sensor 107, and is configured to receive temperature data detected by the temperature sensor 107, and then determine a voltage value output by the current DA module according to the received current temperature and a preset temperature-voltage correspondence, so that the output voltage value is adjusted according to a temperature change, instead of outputting a fixed voltage all the time, so that the circuit can output maximum power at different temperatures.
The output end of the comparator 104 is connected to the first end of the resistor R3, the second end of the resistor R3 is connected to the power detection terminal Cin of the smart power module 101, the second end of the resistor R3 is further connected to the first end of the capacitor C, and the second end of the capacitor C is grounded. The comparator 104 compares the voltage to be measured passing through the clamping circuit 105 with the reference voltage passing through the voltage dividing circuit 105, and when the voltage at the + input end is higher than that at the-input end, namely the reference voltage is higher than the voltage to be measured, the comparator 104 outputs a high level; when the voltage at the "+" input terminal is lower than the "-" input terminal, that is, if the voltage is higher than the reference voltage, the comparator 104 will output a low level to the Cin terminal of the smart power module 101.
After the Cin terminal receives the low level signal, the intelligent power module 101 outputs a fault signal to the Fo terminal of the micro control unit 102 through the Fo terminal of the intelligent power module 101. After receiving the fault signal, the micro control unit 102 controls U, V, W the three-phase signal output end to be closed; the U, V, W three-phase signal input terminal of the intelligent power module 101 does not receive a valid signal, thereby protecting the circuit.
Alternatively, the current sensor 103 may be a current sensor of the type CQ-2335.
In the power module protection circuit provided by the embodiment of the application, the current value of the current to be detected is converted into a voltage signal through the current sensor, the voltage is compared with the reference voltage output by the DA conversion module in the micro control unit, and when the voltage obtained by the current conversion to be detected is greater than the reference voltage, the comparator outputs a control signal to the intelligent power module, so that the intelligent power module outputs a fault signal to the micro control unit, and the micro control unit closes U, V, W three-phase signal output to realize the protection of the circuit. Because the output voltage value of the DA conversion module in the micro control unit can be adjusted through a program, the micro control unit outputs reference voltages with different voltage values, different requirements for the reference voltages under different scenes are met, the universality of the protection circuit is improved, and the protection circuit can be suitable for demagnetization protection circuits of different frequency converters and different motors.
Based on the same technical concept, an embodiment of the present application further provides an electric device, including the power module protection circuit described in any of the foregoing implementation manners.
Optionally, the electric device may be an air conditioner.
Optionally, the air conditioner includes a temperature sensor disposed on the compressor, and is configured to send the collected temperature data to a micro control unit in the power module protection circuit, so that the micro control unit adjusts an output voltage of a DA conversion module in the micro control unit according to a temperature change.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.
It should be noted that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means at least two unless otherwise specified.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.
Claims (10)
1. A power module protection circuit, comprising: the intelligent power module IPM, the micro control unit MCU, the current sensor and the comparator;
the current sensor is connected with a first input end of the comparator and used for converting the collected current to be detected into a voltage signal and inputting the voltage signal to the comparator;
a DA conversion module in the MCU is connected with a second input end of the comparator and used for inputting the reference voltage to the comparator;
the output end of the comparator is connected with a voltage detection terminal Cin of the IPM, and the comparator is used for outputting a control signal to the IPM when the voltage converted by the current to be detected is greater than the reference voltage;
a fault signal output terminal F0 of the IPM is connected with the MCU, and the IPM outputs a fault signal to the MCU when receiving the control signal;
the U, V, W three-phase signal output end of the MCU is respectively connected with the U, V, W three-phase signal input end of the IPM, and the MCU closes the U, V, W three-phase signal output end of the MCU after receiving a fault signal.
2. The power module protection circuit according to claim 1, wherein the MCU is further connected to a temperature sensor for receiving a current temperature detected by the temperature sensor;
and the MCU determines the voltage value output by the DA conversion module in the MCU according to the current temperature.
3. The power module protection circuit of claim 1, further comprising a clamp circuit;
the current sensor is connected with the first input end of the comparator through the clamping circuit.
4. The power module protection circuit of claim 3, wherein the clamp circuit comprises a first diode and a second diode;
the cathode of the first diode is connected with a power supply, the anode of the first diode is connected with the cathode of the second diode, and the anode of the second diode is connected with the ground;
and the anode of the first diode is respectively connected with the current sensor and the first input end of the comparator.
5. The power module protection circuit of claim 1, further comprising a voltage divider circuit;
and the DA conversion module in the MCU is connected with the second input end of the comparator through the voltage division circuit.
6. The power module protection circuit of claim 5, wherein the voltage divider circuit comprises a first resistor and a second resistor;
the first end of the first resistor is connected with a DA conversion module in the MCU, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with the ground;
and the second end of the first resistor is used as the output end of the voltage division circuit and is connected with the second input end of the comparator.
7. The power module protection circuit of claim 1, further comprising a third resistor and a first capacitor;
a first end of the third resistor is connected with the output end of the comparator, and a second end of the third resistor is connected with the voltage detection terminal Cin of the IPM;
the first end of the first capacitor is connected with the second end of the third resistor, and the second end of the first capacitor is connected with the ground.
8. An electric device comprising the power module protection circuit according to any one of claims 1 to 7.
9. The electrical equipment of claim 8, wherein the electrical equipment is an air conditioner.
10. The consumer of claim 9, wherein the air conditioner comprises a temperature sensor disposed on the compressor;
and the temperature sensor is connected with the MCU in the power module protection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021731039.8U CN212572065U (en) | 2020-08-18 | 2020-08-18 | Power module protection circuit and consumer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021731039.8U CN212572065U (en) | 2020-08-18 | 2020-08-18 | Power module protection circuit and consumer |
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| CN212572065U true CN212572065U (en) | 2021-02-19 |
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| CN202021731039.8U Active CN212572065U (en) | 2020-08-18 | 2020-08-18 | Power module protection circuit and consumer |
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