CN110542487A - Temperature detection circuit and method - Google Patents
Temperature detection circuit and method Download PDFInfo
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- CN110542487A CN110542487A CN201910744414.8A CN201910744414A CN110542487A CN 110542487 A CN110542487 A CN 110542487A CN 201910744414 A CN201910744414 A CN 201910744414A CN 110542487 A CN110542487 A CN 110542487A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
Abstract
The invention provides a temperature detection circuit and a method, wherein a plurality of temperature sensors are placed in a detected object, one temperature sensor is used as a main temperature sensor, the other temperature sensors are used as standby temperature sensors, each temperature sensor is connected to a control chip through a corresponding signal processing circuit, the signal processing circuit structure of each path is the same, whether the signal of the main temperature sensor is normal or not is detected firstly after the main temperature sensor is electrified, when the main temperature sensor fails, one of the standby temperature sensors is selected as the main temperature sensor, and the temperature signal is transmitted to the control chip through the corresponding signal processing circuit, so that the control chip can continuously monitor the temperature of the detected object, and the reliability of the temperature detection and the system of the detected object is improved; the temperature detection circuit processes the temperature signal of the measured object through filtering, following, optical coupling isolation, differential amplification and the like, and improves the anti-interference capability and accuracy of the temperature detection system of the measured object in a strong electromagnetic interference environment.
Description
Technical Field
The invention relates to the field of temperature detection, in particular to a temperature detection circuit and a temperature detection method.
background
the driving motor is one of the most key and most core parts of the electric automobile, and in the running process of the driving motor, because of different driving road conditions of the electric automobile, particularly when the electric automobile accelerates and climbs a slope, the current flowing through the stator of the motor is very large, the temperature change is very large, and strong electromagnetic interference also exists. The motor damage may be caused by the over-high temperature of the driving motor, especially the permanent magnet synchronous motor, and the over-high temperature may cause the demagnetization of the driving motor, even cause serious accidents. Therefore, in the motor control system, the motor driver needs to detect and monitor the temperature of the motor to ensure the safety of the motor and the control system.
in the prior art, a method generally adopted for measuring the temperature of a stator of a driving motor of an electric vehicle is to place a temperature sensor, generally a resistance sensor, in the stator of the driving motor, and connect a signal of the temperature sensor to a motor driver through a relevant interface, so as to realize detection and monitoring of the temperature of the driving motor. However, in a strong electromagnetic environment, the temperature of the motor is greatly interfered, so that the detected temperature is very inaccurate and cannot be accurately monitored, and the electromagnetic interference enters the driver through the connecting wire and seriously interferes the normal work of other parts of the driver; and a temperature sensor detects the temperature of the driving motor, when the temperature of the motor fails due to damage of the sensor or breakage of a connecting wire between the motor and the driver, the driver loses monitoring on the temperature of the driving motor, and the reliability is poor.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a temperature detection circuit and a temperature detection method, so as to ensure that the temperature of a detected object is continuously monitored when a main temperature sensor fails, and the reliability of the temperature detection and system of the detected object is improved; and the anti-interference capability of the temperature signal and the accuracy of temperature detection are improved.
The purpose of the invention is realized by the following technical scheme: the utility model provides a temperature detection circuit, includes temperature detection circuit and control chip, its characterized in that, temperature detection circuit includes main temperature sensor, at least one reserve temperature sensor, main signal processing circuit and the reserve signal processing circuit who corresponds with reserve temperature sensor quantity, main temperature sensor and reserve temperature sensor all place on the measured object, main signal processing circuit with reserve signal processing circuit structure is the same, main temperature sensor detects behind the temperature signal of measured object, through main signal processing circuit converts voltage signal transmission extremely control chip establishes a reserve sensor into main temperature sensor when main temperature sensor trouble, main signal processing circuit includes: the input end of the filter circuit is connected with the main temperature sensor and is used for filtering the circuit;
The input end of the voltage division circuit is connected with the output end of the filter circuit, and the voltage division circuit and the main temperature sensor form a voltage division circuit and convert a temperature signal of a measured object detected by the main temperature sensor into a measurable voltage signal; the input end of the voltage isolation circuit is connected with the output end of the voltage division circuit, and the voltage isolation circuit isolates part of electromagnetic interference of the voltage signal and then outputs a low-noise voltage signal; a voltage amplifying circuit; the input end of the voltage amplifying circuit is connected with the output end of the voltage isolating circuit, the voltage amplifying circuit amplifies the low-noise voltage signal and improves the anti-interference capability, and the amplified voltage signal is transmitted to the control chip.
Further, the filter circuit includes electric capacity C3, electric capacity C4, inductance L1, electric capacity C3's one end is connected main temperature sensor's one end and common port are connected inductance L1's first input end, electric capacity C3's the other end is connected main temperature sensor's the other end and common port are connected inductance L1's second input end, inductance L1's first output end is connected electric capacity C4's one end and common port are connected voltage divider circuit's first input end, inductance L1's second output end is connected electric capacity C4's the other end and common port are connected voltage divider circuit's second input end.
Further, the voltage divider circuit includes a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a power supply V1, an operational amplifier U1, and a capacitor C12, wherein one end of the resistor R1 is connected to one end of the capacitor C1, and a common end of the resistor R1 is connected to the first output end of the filter circuit, the other end of the capacitor R1 is connected to the power supply V1, and a common end of the capacitor C1 is connected to the other end of the capacitor C2, one end of the resistor R2 is connected to one end of the capacitor C2, and a common end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1 and the second output end of the filter circuit, the other end of the resistor R2 is connected to the other end of the capacitor and a common end of the capacitor is grounded, an inverting input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1.
further, voltage isolation circuit includes opto-coupler U2, power V2 and power V1, the anodal connection of the luminous end of opto-coupler U2 power V1, the negative pole of the luminous end of opto-coupler U2 is connected bleeder circuit's output, the positive pole that the luminous end of opto-coupler U2 received the light is connected voltage amplification circuit's first input end, the negative pole that the luminous end of opto-coupler U2 received the light is connected voltage amplification circuit's second input, a port of opto-coupler U2 is connected power V2, power V2 does the opto-coupler receives the light and holds and provide voltage.
Further, the voltage amplifying circuit includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a capacitor C6, a capacitor C7, an operational amplifier U3, a diode D1, a diode D2, and a power supply V2, one end of the resistor R3 is connected to the first output terminal of the voltage isolating circuit, the other end of the resistor R3 is connected to one end of the capacitor C5 and a common terminal thereof is connected to one end of the resistor R5 and a non-inverting input terminal of the operational amplifier U5, the other end of the capacitor C5 is connected to the other end of the resistor R5 and a common terminal thereof is connected to one end of the resistor R5 and one end of the capacitor C5, the other end of the resistor R5 is connected to the second output terminal of the voltage isolating circuit, the other end of the resistor R5 is connected to the other end of the capacitor C5 and the common terminal thereof is connected to one output terminal of the operational amplifier U5 and one end of the resistor R5 and one output terminal of the operational amplifier U5 And the other end of the resistor R7 is connected with one end of the capacitor C7, the common end of the resistor R7 is connected with the cathode of the diode D1, the anode of the diode D2 and one input port of the control chip, the other end of the capacitor C7 is grounded, the anode of the diode D1 is grounded, and the cathode of the diode D2 is connected with the V2.
Further, the main temperature sensor and/or the standby temperature sensor are/is an NTC type thermistor and/or a PT100 temperature sensor.
Further, the optical coupler U2 is a linear optical coupler.
The temperature detection method is characterized in that the temperature detection circuit provided by the invention is adopted, and the method comprises the following steps: s1: the main signal processing circuit receives a temperature signal of a measured object acquired by the main temperature sensor and converts the temperature signal of the measured object into a voltage signal; s2: the control chip receives the voltage signal and judges whether the temperature signal of the main temperature sensor is normal or not according to the voltage signal; s3: if the temperature signal is normal, continuously acquiring the temperature information of the measured object; and if the temperature signal is abnormal, selecting one standby temperature sensor and a standby signal processing circuit corresponding to the standby temperature sensor as the main temperature sensor and the main signal processing circuit.
Further, the step S1 includes the following steps: s101: the filter circuit filters the temperature signal detected by the main temperature sensor; s102: the voltage division circuit converts the temperature signal into a voltage signal; s103: the voltage signal removes part of electromagnetic interference through a voltage isolation circuit and realizes voltage isolation; s104: and amplifying the isolated voltage signal by a voltage amplifying circuit and transmitting the amplified voltage signal to a control chip.
The invention has the beneficial effects that: the invention provides a temperature detection circuit and a method, wherein a plurality of temperature sensors are placed in a measured object, one temperature sensor is used as a main temperature sensor, the other temperature sensors are used as standby temperature sensors, each temperature sensor is connected to a control chip through a corresponding signal processing circuit, the signal processing circuit structure of each path is the same, after being electrified, whether the signal of the main temperature sensor is normal or not is detected, and if the signal is normal, the detected temperature signal is output; if the temperature of the detected object is abnormal, one of the standby temperature sensors is selected as a main temperature sensor, the temperature signal is transmitted to the control chip through the corresponding signal processing circuit, the control chip selects the normal signal to output, the control chip can continuously monitor the temperature of the detected object, and the reliability of the temperature detection and the system of the detected object is improved; the temperature detection circuit processes the temperature signal of the measured object through filtering, following, optical coupling isolation, differential amplification and the like, and the anti-interference performance and the accuracy of the temperature detection system of the measured object in a strong electromagnetic interference environment are improved.
Drawings
the invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived on the basis of the following drawings without inventive effort.
Fig. 1 is a schematic circuit diagram of an embodiment of a temperature detection circuit according to the present invention.
FIG. 2 is a schematic flow chart diagram illustrating one embodiment of a temperature detection method of the present invention.
Fig. 3 is a schematic signal processing flow diagram of an embodiment of a temperature detection method of the present invention.
FIG. 4 is a flow chart of temperature sensor selection and temperature signals for one embodiment of a temperature detection method of the present invention.
Wherein the reference numbers are as follows: 10: the voltage-dividing circuit comprises a filter circuit, a voltage-dividing circuit, a voltage isolating circuit and a voltage amplifying circuit, wherein the filter circuit comprises 20 parts of a voltage-dividing circuit, 30 parts of a voltage isolating circuit and 40 parts of a voltage amplifying circuit.
Detailed Description
In order to make the technical solutions of the present invention better understood, 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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
The temperature detection circuit of this embodiment is used for electric automobile driving motor's temperature to detect, and electric automobile driving motor often is in the temperature variation, and has under very strong electromagnetic interference's the environment, and the temperature detection circuit of this embodiment can realize accurate, reliable, effectual acquisition driving motor temperature under high-temperature difference, strong magnetic environment.
As shown in fig. 1, a temperature detecting circuit of this embodiment includes a main temperature sensor, a backup temperature sensor, a main signal processing circuit, a backup signal processing circuit, and a control chip, wherein the main temperature sensor and the backup temperature sensor both use NTC type thermistors, the control chip is an MCU, the main temperature sensor and the backup temperature sensor are both disposed in a stator of a driving motor, the main signal processing circuit and the backup signal processing circuit have the same structure, the main temperature sensor detects a temperature signal of the motor, the temperature signal is converted into a voltage signal by the main signal processing circuit and transmitted to the control chip, and since the backup signal processing circuit and the main signal processing circuit have the same structure, only the main signal circuit is explained in detail, wherein the NTC thermistors refer to the main sensor, and the signal processing circuit refers to the main signal processing circuit, it should be understood that the following explanation of the primary temperature sensor and the primary signal processing circuit applies to the backup temperature sensor and the backup signal processing circuit.
The signal processing circuit as described above includes: the input end of the filter circuit 10 is connected with the NTC thermistor and is used for filtering the circuit; the input end of the voltage division circuit 20 is connected with the output end of the filter circuit 10, the voltage division circuit 20 and the NTC thermistor form a voltage division circuit, and the resistance value change of the NTC thermistor caused by the temperature change of the motor is converted into a measurable voltage signal; the input end of the voltage isolation circuit 30 is connected with the output end of the voltage division circuit 20, and the voltage isolation circuit 30 isolates part of electromagnetic interference of the voltage signal output by the voltage division circuit 20 and outputs a low-noise voltage signal; a voltage amplifying circuit 40; the input end of the voltage amplifying circuit 40 is connected with the output end of the voltage isolating circuit 30, the voltage amplifying circuit 40 amplifies the low-noise voltage signal with part of electromagnetic interference isolated and improves the anti-interference capability of the low-noise voltage signal, and the amplified low-noise voltage signal is transmitted to the MCU.
The filter circuit 10 includes a capacitor C3, a capacitor C4, and a common mode inductor L1, one end of the capacitor C3 is connected to one end of the NTC thermistor, and a common end of the capacitor C3 is connected to the other end of the NTC thermistor, and a common end of the capacitor C3 is connected to a second input end of the common mode inductor L1, a first output end of the common mode inductor L1 is connected to one end of the capacitor C4, and a common end of the capacitor C4 is connected to a first input end of the voltage divider circuit 20, a second output end of the common mode inductor L1 is connected to the other end of the capacitor C4, and a common end of the capacitor C4 is connected to a second input end of the voltage divider circuit 20, the common mode inductor L1, the capacitor C3, and the capacitor C4 form an LC filter circuit, common mode electromagnetic interference signals in the circuit are filtered through the common mode inductor L1.
The voltage divider circuit 20 includes a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a power supply V1, an operational amplifier U1, and a capacitor C12, wherein one end of the resistor R1 is connected to one end of the capacitor C1 and the common end is connected to one end of the capacitor C4 of the filter circuit 10, the other end of the capacitor R1 is connected to the power supply V1 and the common end is connected to the other end of the capacitor C1, one end of the resistor R2 is connected to one end of the capacitor C2 and the common end is connected to the non-inverting input end of the operational amplifier U1 and the other end of the capacitor C4 of the filter circuit, the other end of the resistor R2 is connected to the other end of the capacitor and the common end is grounded, the inverting input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1 and the common end is connected to one end of the capacitor C12 and the input end of the voltage isolating circuit, the other end of the capacitor C12 is grounded, the other end of the filter, the resistance value of the NTC thermistor is greatly influenced by temperature, when the temperature changes, the resistance value of the NTC thermistor changes, so that the voltage at two ends of the resistor R2 changes, the voltage input to the same-phase end of the operational amplifier U1 changes, the resistance value change of the NTC thermistor caused by the temperature change is converted into a measurable point voltage signal, the operational amplifier U1 is formed into a follower in the voltage division circuit 20, the driving capability of the input voltage signal is improved and then output, the output end of the follower is connected with a capacitor C12 for filtering, the resistor R1 and the capacitor C1 for filtering in parallel, the resistor R2 and the capacitor C2 for filtering in parallel, and the V1 is used for supplying power to the sensor and the temperature signal processing circuit.
The voltage isolation circuit 30 comprises a linear optical coupler U2, a power supply V1 and a power supply V2, the positive electrode of the light emitting end of the linear optical coupler U2 is connected with the power supply V1, the negative electrode of the light emitting end of the linear optical coupler U2 is connected with the output end of an operational amplifier U1 of the voltage division circuit 20, the positive electrode of the light receiving end of the optical coupler U2 is connected with the first input end of the voltage amplification circuit 40, the negative electrode of the light receiving end of the optical coupler U2 is connected with the second input end of the voltage amplification circuit 40, the power supply V2 is connected with one port of the linear optical coupler U2, voltage is provided for the light receiving end of the linear optical coupler U2, voltage isolation is achieved through the linear optical coupler U2, partial electromagnetic interference signals of input voltage signals are isolated from the voltage amplification circuit 40, meanwhile, the output voltage signals are equal in size.
The voltage amplifying circuit 40 comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a capacitor C6, a capacitor C7, an operational amplifier U3, a diode D1 and a power supply V1, wherein one end of the resistor R1 is connected with a first output end of a linear optical coupler U1 of the voltage isolating circuit 30, the other end of the resistor R1 is connected with one end of the capacitor C1, a common end of the resistor R1 is connected with one end of the resistor R1 and a non-inverting input end of the operational amplifier U1, the other end of the capacitor C1 is connected with the other end of the resistor R1 and the common end of the resistor R1 is connected with one end of the resistor R1 and one end of the capacitor C1, the other end of the resistor R1 is connected with a second output end of the linear optical coupler U1 of the voltage isolating circuit 30, the other end of the resistor R1 is connected with the other end of the common end of the capacitor C1 and one, the other end of the resistor R7 is connected with one end of a capacitor C7, the common end of the resistor R7 is connected with the cathode of a diode D1, the anode of the diode D2 and one input port of a control chip, the other end of the capacitor C7 is grounded, the anode of the diode D1 is grounded, the cathode of a diode D2 is connected with a V2, a resistor R3, a resistor R4, a resistor R5, a capacitor C5, a resistor R6, a capacitor C6 and an operational amplifier U3 form a differential amplification circuit, the voltage signal output by the linear optocoupler U2 is amplified or reduced by the differential amplification circuit, the anti-jamming capability of the voltage signal is improved, the resistor R5 and the capacitor C5 form parallel filtering, the resistor R6 and the capacitor R6 form parallel filtering, the amplified voltage signal enters the MCU through the output end of the operational amplifier U3 and the resistor R7, the resistor R7 and the capacitor R7 form a low-pass filtering circuit, the diode D1 and the diode D2 are silicon, when the voltage of the operational amplifier U3 after passing through the resistor R7 is lower than 0V, the diode D1 is turned on, at this time, the diode D1 enables the voltage signal entering the MCU to be-0.7V at the lowest, and when the voltage of the operational amplifier U3 after passing through the resistor R7 is larger than UV2, the diode D1 turns on the diode D2 to enable the voltage signal input to the MCU to be (UV 2+ 0.7) V at the highest, so that the voltage signal input to the MCU is limited within the bearable range of the MCU.
The working principle of the motor temperature detection circuit of the embodiment is as follows: the NTC thermistor performs filtering through a filter circuit formed by a capacitor C3, a common-mode inductor L1 and a capacitor C4; the resistor R1, the NTC thermistor and the resistor R2 form a voltage division circuit, temperature signals are converted into measurable temperature voltage signals, then the temperature voltage signals are input to the input end of the linear optocoupler U2 after passing through a follower formed by an operational amplifier U1, wherein the follower is used for improving the driving capability of the temperature voltage signals, the linear optocoupler U2 is used for isolating the temperature voltage signals, and partial electromagnetic interference is isolated from other parts of the driver through the linear optocoupler U2, so that the influence of the electromagnetic interference on the normal work of other parts is avoided; the resistor R3, the resistor R4, the resistor R5, the capacitor C5, the resistor R6, the capacitor C6 and the operational amplifier U3 form a differential amplification circuit, and the differential amplification circuit is used for amplifying or reducing the temperature voltage signals and improving the anti-interference capacity of the temperature voltage signals; the amplified temperature voltage signal enters the MCU through the output end of the operational amplifier U3 through the resistor R7, wherein the temperature voltage signal is limited within the tolerable range of the MCU by the diodes D1 and D2; temperature change signals sensed by the NTC thermistor are processed through filtering, following, optical coupling isolation, differential amplification and the like, and therefore the anti-interference performance and the accuracy of the motor temperature detection system in a strong electromagnetic interference environment are improved.
As shown in fig. 2 to 4, the present embodiment further provides a method for detecting a motor temperature, where the method for detecting a motor temperature of the present embodiment is implemented by using the motor temperature detection circuit of the present embodiment, and includes the following steps: s1: the signal processing circuit processes the NTC thermistor to acquire a temperature signal of the motor (namely the resistance value change of the NTC thermistor), and converts the temperature signal of the motor into a voltage signal; s2: the MCU receives the voltage signal and judges whether the temperature signal acquired by the NTC thermistor is normal or not according to the voltage signal; s3: if the temperature signal is normal, continuously acquiring the temperature of the driving motor through the NTC thermistor; if the temperature signal is abnormal, the spare NTC thermistor and the corresponding signal processing circuit are selected to acquire the temperature of the driving motor.
In this embodiment, the signal processing circuit processes the motor temperature signal obtained by the NTC thermistor through the following steps, S101: the filter circuit 10 filters a temperature signal (i.e., resistance change of the thermistor) detected by the NTC thermistor; s102: the voltage division circuit converts the temperature signal into a measurable temperature voltage signal; s103: the temperature voltage signal removes part of electromagnetic interference through a voltage isolation circuit and realizes voltage isolation; s104: and amplifying the isolated temperature voltage signal by a voltage amplifying circuit and transmitting the amplified temperature voltage signal to a control chip.
the specific implementation process of the embodiment: the motor temperature detection circuit of the embodiment is used for a driving motor of an electric automobile, two NTC thermistors which are respectively a main NTC thermistor and a standby NTC thermistor are arranged in the driving motor of the automobile, the main NTC thermistor is used for detecting the temperature of the motor, when the temperature detection of the NTC thermistors fails, the standby NTC thermistors are used for detecting the temperature of the motor, the two NTC thermistors are connected to a signal processing circuit through related interfaces, generally, in the electric automobile, the connecting line between the motor and the signal processing circuit is longer, and in a strong electromagnetic interference environment, signals of the NTC thermistors are easily interfered, so that the detection is inaccurate; after the power-on initialization, the MCU starts to receive a main NTC thermistor signal, judges whether the main NTC thermistor temperature detection signal is normal or not, and switches to a standby NTC thermistor for temperature detection if a fault occurs, so that when the main NTC thermistor is abnormal due to the damage, disconnection and other conditions of the main NTC thermistor, the normal operation of temperature detection of the driving motor is ensured, and the reliability of temperature detection is improved.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (10)
1. The utility model provides a temperature detection circuit, includes temperature detection circuit and control chip, its characterized in that, temperature detection circuit includes main temperature sensor, at least one reserve temperature sensor, main signal processing circuit and the reserve signal processing circuit who corresponds with reserve temperature sensor quantity, main temperature sensor and reserve temperature sensor all place on the measured object, main signal processing circuit with reserve signal processing circuit structure is the same, main temperature sensor detects behind the temperature signal of measured object, through main signal processing circuit converts voltage signal transmission extremely control chip establishes a reserve sensor into main temperature sensor when main temperature sensor trouble, main signal processing circuit includes:
The input end of the filter circuit is connected with the main temperature sensor and is used for filtering the circuit;
The input end of the voltage division circuit is connected with the output end of the filter circuit, and the voltage division circuit and the main temperature sensor form a voltage division circuit and convert a temperature signal of a measured object detected by the main temperature sensor into a measurable voltage signal;
The input end of the voltage isolation circuit is connected with the output end of the voltage division circuit, and the voltage isolation circuit isolates part of electromagnetic interference of the voltage signal and then outputs a low-noise voltage signal;
A voltage amplifying circuit; the input end of the voltage amplifying circuit is connected with the output end of the voltage isolating circuit, the voltage amplifying circuit amplifies the low-noise voltage signal and improves the anti-interference capability, and the amplified voltage signal is transmitted to the control chip.
2. The temperature detecting circuit as claimed in claim 1, wherein the filter circuit comprises a capacitor C3, a capacitor C4, and an inductor L1, one end of the capacitor C3 is connected to one end of the main temperature sensor and the common end thereof is connected to the first input end of the inductor L1, the other end of the capacitor C3 is connected to the other end of the main temperature sensor and the common end thereof is connected to the second input end of the inductor L1, the first output end of the inductor L1 is connected to one end of the capacitor C4 and the common end thereof is connected to the first input end of the voltage divider circuit, and the second output end of the inductor L1 is connected to the other end of the capacitor C4 and the common end thereof is connected to the second input end of the voltage divider circuit.
3. The temperature detecting circuit as claimed in claim 1, wherein the voltage divider circuit comprises a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a power supply V1, an operational amplifier U1 and a capacitor C12, one end of the resistor R1 is connected to one end of the capacitor C1 and the common end is connected to the first output end of the filter circuit, the other end of the capacitor R1 is connected to the power supply V1 and the common end is connected to the other end of the capacitor C1, one end of the resistor R2 is connected to one end of the capacitor C2 and the common end is connected to the non-inverting input end of the operational amplifier U1 and the second output end of the filter circuit, the other end of the resistor R2 is connected to the other end of the capacitor and the common end is grounded, the inverting input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1 and the common end of the capacitor C12 is connected to the input end of the voltage isolator circuit, the other end of the capacitor C12 is grounded.
4. The temperature detection circuit of claim 1, wherein the voltage isolation circuit comprises an optical coupler U2, a power supply V1 and a power supply V2, an anode of a light emitting end of the optical coupler U2 is connected to the power supply V1, a cathode of a light emitting end of the optical coupler U2 is connected to an output end of the voltage division circuit, an anode of a light receiving end of the optical coupler U2 is connected to a first input end of the voltage amplification circuit, a cathode of a light receiving end of the optical coupler U2 is connected to a second input end of the voltage amplification circuit, a port of the optical coupler U2 is connected to the power supply V2, and the power supply V2 provides voltage for the light receiving end of the optical coupler.
5. The temperature detecting circuit as claimed in claim 1, wherein the voltage amplifying circuit includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a capacitor C6, a capacitor C7, an operational amplifier U3, a diode D1, a diode D2 and a power supply V2, one end of the resistor R3 is connected to the first output terminal of the voltage isolating circuit, the other end of the resistor R3 is connected to one end of the capacitor C5 and the common terminal is connected to one end of the resistor R5 and the non-inverting input terminal of the operational amplifier U3, the other end of the capacitor C5 is connected to the other end of the resistor R5 and the common terminal is grounded, the inverting input terminal of the operational amplifier U3 is connected to one end of the resistor R4 and the common terminal of the resistor R6 and one end of the capacitor C6, the other end of the resistor R4 is connected to the second output terminal of the voltage isolating circuit, the other end of the resistor R6 is connected with the other end of the capacitor C6 and the common end is connected with the output end of the operational amplifier U3 and one end of the resistor R7, the other end of the resistor R7 is connected with one end of the capacitor C7 and the common end is connected with the cathode of the diode D1, the anode of the diode D2 and one input port of the control chip, the other end of the capacitor C7 is grounded, the anode of the diode D1 is grounded, and the cathode of the diode D2 is connected with V2.
6. a temperature sensing circuit according to claim 1, wherein the primary and/or backup temperature sensors are NTC type thermistors and/or PT100 temperature sensors.
7. the temperature detection circuit as claimed in claim 4, wherein said optocoupler U2 is a linear optocoupler.
8. A temperature detection method using the temperature detection circuit according to any one of claims 1 to 7, comprising the steps of:
S1: the main signal processing circuit receives a temperature signal of a measured object acquired by the main temperature sensor and converts the temperature signal of the measured object into a voltage signal;
S2: the control chip receives the voltage signal and judges whether the temperature signal of the main temperature sensor is normal or not according to the voltage signal;
S3: if the temperature signal is normal, continuously acquiring the temperature information of the measured object; and if the temperature signal is abnormal, selecting one standby temperature sensor and a standby signal processing circuit corresponding to the standby temperature sensor as the main temperature sensor and the main signal processing circuit.
9. The temperature detecting method according to claim 8, wherein the step S1 of processing the temperature signal of the main temperature sensor comprises the steps of:
S101: the filter circuit filters the temperature signal detected by the main temperature sensor;
s102: the voltage division circuit converts the temperature signal into a voltage signal;
S103: the voltage signal removes part of electromagnetic interference through a voltage isolation circuit and realizes voltage isolation;
s104: and amplifying the isolated voltage signal by a voltage amplifying circuit and transmitting the amplified voltage signal to a control chip.
10. the method according to claim 8, wherein the object to be measured is a motor, and the primary temperature sensor and the backup temperature sensor are both disposed on a stator of the motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910744414.8A CN110542487A (en) | 2019-08-13 | 2019-08-13 | Temperature detection circuit and method |
Applications Claiming Priority (1)
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| CN112729186A (en) * | 2020-12-21 | 2021-04-30 | 珠海格力电器股份有限公司 | Fault processing method, device and system for displacement sensor and processor |
| CN115013342A (en) * | 2022-05-26 | 2022-09-06 | 中航光电科技股份有限公司 | Redundancy-designed fan rotating speed control system and method |
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Application publication date: 20191206 |