PTC motor temperature detection circuit and motor control device

Abstract

The utility model discloses a PTC motor temperature detection circuit and a motor control device, comprising a PTC sampling circuit and a one-chip microcomputer circuit, the PTC sampling circuit comprises a PTC thermistor used for detecting motor temperature, a divider resistor R1, a divider resistor R2 and a divider resistor R3, the divider resistor R1, the PTC thermistor, the divider resistor R2 and the divider resistor R3 are sequentially connected in series in a power supply loop along the flow direction of current; the single-chip microcomputer circuit is provided with a first voltage sampling port, a second voltage sampling port and a third voltage sampling port, the first voltage sampling port collects voltage V1 between the PTC thermistor and the divider resistor R1, and the second voltage sampling port collects voltage V2 between the PTC thermistor and the divider resistor R2. The third voltage sampling port collects the voltage V3 between the divider resistor R2 and the divider resistor R3. According to the utility model, the resistance value of the PTC thermistor is only related to the divider resistor R2, so that the temperature drift is greatly reduced, and the motor temperature detection precision can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature detection, in particular to a PTC motor temperature detection circuit and a motor control device. Background Art

[0002] The motor will generate heat during use. If it is not discovered in time and certain cooling and temperature control treatment is not carried out, it will cause damage to the motor due to overheating. For this reason, a motor temperature sampling circuit is usually used to detect the motor temperature. The PTC motor temperature detection circuit is one of them. It uses the characteristic that the resistance value of the PTC thermistor changes with the motor temperature to monitor the motor temperature.

[0003] However, traditional PTC motor temperature sampling circuits are mostly suitable for scenarios where the motor temperature and resistance change slightly. If the temperature is high in the external conditions, the motor temperature and resistance often change greatly, which can easily cause temperature drift of the circuit components in the sampling circuit, and also lead to large errors in the detected motor temperature. Therefore, how to improve the detection accuracy of motor temperature is a key issue that technicians in this field are concerned about. Utility Model Content

[0004] The utility model aims at the technical problems existing in the prior art and provides a PTC motor temperature detection circuit and a motor control device.

[0005] The utility model solves the technical problem by adopting the following technical scheme: a PTC motor temperature detection circuit comprises a PTC sampling circuit and a single-chip microcomputer circuit for collecting voltage and outputting a control signal, wherein the PTC sampling circuit comprises a PTC thermistor for detecting the motor temperature; the PTC sampling circuit further comprises at least one voltage-dividing resistor R1, at least one voltage-dividing resistor R2 and at least one voltage-dividing resistor R3, wherein the voltage-dividing resistor R1, the PTC thermistor, the voltage-dividing resistor R2 and the voltage-dividing resistor R3 are sequentially connected in series in a power supply circuit along the flow direction of the current; the single-chip microcomputer circuit comprises a first voltage sampling port, a second voltage sampling port and a third voltage sampling port, wherein the first voltage sampling port collects a voltage V1 between the PTC thermistor and the voltage-dividing resistor R1, the second voltage sampling port collects a voltage V2 between the PTC thermistor and the voltage-dividing resistor R2, and the third voltage sampling port collects a voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3.

[0006] Furthermore, the PTC sampling circuit also includes capacitor C1, capacitor C2 and capacitor C3, one end of capacitor C1 is connected to the connection point of the voltage-dividing resistor R1 and the PTC thermistor, one end of capacitor C2 is connected to the connection point of the PTC thermistor and the voltage-dividing resistor R2, one end of capacitor C3 is connected to the connection point of the voltage-dividing resistor R2 and the voltage-dividing resistor R3, and the other end of capacitor C1, the other end of capacitor C2 and the other end of capacitor C3 are respectively connected to the negative pole of the power supply circuit.

[0007] Furthermore, the PTC sampling circuit also includes a current limiting resistor R4, a current limiting resistor R5 and a current limiting resistor R6, the current limiting resistor R4 is connected between the first voltage sampling port and the connection point between the voltage dividing resistor R1 and the PTC thermistor, the current limiting resistor R5 is connected between the second voltage sampling port and the connection point between the PTC thermistor and the voltage dividing resistor R2, and the current limiting resistor R6 is connected between the third voltage sampling port and the connection point between the voltage dividing resistor R2 and the voltage dividing resistor R3.

[0008] Furthermore, the single-chip microcomputer circuit includes a single-chip microcomputer with an AD conversion function, the VDD terminal of the single-chip microcomputer is connected to the positive pole of the power supply circuit, the VSS terminal of the single-chip microcomputer is connected to the negative pole of the power supply circuit, the AN0 terminal of the single-chip microcomputer constitutes the first voltage sampling port, the AN1 terminal constitutes the second voltage sampling port, and the RA2 terminal constitutes the third voltage sampling port.

[0009] Furthermore, the single-chip microcomputer circuit further includes a capacitor C4, one end of the capacitor C4 is connected to the VDD terminal of the single-chip microcomputer, and the other end of the capacitor C4 is connected to the negative electrode of the power supply circuit.

[0010] Furthermore, the model of the single chip microcomputer is PIC12F1501.

[0011] Furthermore, the negative pole of the power supply circuit is grounded.

[0012] The utility model further provides a motor control device, including a relay for controlling the on and off of a circuit where the motor is located, and a relay control output circuit connected to the relay; it also includes the PTC motor temperature detection circuit as described in the utility model above, and the output of the single-chip microcomputer circuit is connected to the relay control output circuit.

[0013] Furthermore, it also includes a power input conversion circuit, which supplies power to the relay control output circuit, and the output of the power input conversion circuit forms the power supply loop.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] 1. Since the PTC sampling circuit of the utility model further includes a voltage-dividing resistor R1, a voltage-dividing resistor R2 and a voltage-dividing resistor R3, the voltage-dividing resistor R1, the PTC thermistor, the voltage-dividing resistor R2 and the voltage-dividing resistor R3 are sequentially connected in series in the power supply circuit along the flow direction of the current, the single-chip circuit has a first voltage sampling port, a second voltage sampling port and a third voltage sampling port, the first voltage sampling port collects the voltage V1 between the PTC thermistor and the voltage-dividing resistor R1, the second voltage sampling port collects the voltage V2 between the PTC thermistor and the voltage-dividing resistor R2, and the third voltage sampling port collects the voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3, so that the resistance value of the PTC thermistor of the utility model is only related to the voltage V1, the voltage V2, the voltage V3 and the voltage-dividing resistor R2, and the voltage V1, the voltage V2 and the voltage V3 change synchronously, and they are affected by temperature in the same way, and it can be considered that the temperature drift is zero or substantially zero, so the resistance value of the PTC thermistor is only related to the voltage-dividing resistor R2, and the voltage-dividing resistor R2 is little affected by temperature. Therefore, the utility model greatly reduces the temperature drift and can greatly improve the detection accuracy of the motor temperature.

[0016] 2. The setting of the voltage-dividing resistor R1 can prevent the end of the PTC thermistor connected to the voltage-dividing resistor R1 from being mistakenly connected to a voltage higher than the power supply circuit and damaging components such as the microcontroller.

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments; however, the PTC motor temperature detection circuit and motor control device of the present invention are not limited to the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the PTC motor temperature detection circuit of the utility model;

[0019] Figure 2 It is a principle block diagram of the motor control device of the utility model;

[0020] In the figure, 1. single chip microcomputer circuit, 2. PTC sampling circuit, 3. relay control output circuit, 4. power input conversion circuit. DETAILED DESCRIPTION

[0021] In the present invention, the terms "first", "second", "third", etc. are only used to distinguish similar objects, not to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "at least one" means one or more, and "more than one" means two or more.

[0022] See also Figure 1As shown, a PTC motor temperature detection circuit of the utility model includes a PTC sampling circuit 2, a single-chip computer circuit 1 for collecting voltage and outputting a control signal, the PTC sampling circuit 2 includes a PTC thermistor PTC for detecting the motor temperature, at least one voltage-dividing resistor R1, at least one voltage-dividing resistor R2 and at least one voltage-dividing resistor R3, the voltage-dividing resistor R1, the PTC thermistor PTC, the voltage-dividing resistor R2 and the voltage-dividing resistor R3 are sequentially connected in series in the power supply circuit along the flow direction of the current. The single-chip computer circuit 1 has a first voltage sampling port, a second voltage sampling port and a third voltage sampling port, the first voltage sampling port collects the voltage V1 between the PTC thermistor PTC and the voltage-dividing resistor R1 (i.e., the upper end voltage of the PTC thermistor PTC), the second voltage sampling port collects the voltage V2 between the PTC thermistor PTC and the voltage-dividing resistor R2 (i.e., the lower end voltage of the PTC thermistor PTC), and the third voltage sampling port collects the voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3.

[0023] In this embodiment, the number of the voltage-dividing resistor R1, the voltage-dividing resistor R2, and the voltage-dividing resistor R3 is one, but not limited thereto. In other embodiments, the number of the voltage-dividing resistor R1, the voltage-dividing resistor R2, and the voltage-dividing resistor R3 can be multiple. When the number of the voltage-dividing resistor R1 is multiple, the multiple voltage-dividing resistors R1 are connected in series and are all located on the upstream side of the PTC thermistor. At this time, the first voltage sampling port collects the voltage V1 between the PTC thermistor and the voltage-dividing resistor R1 adjacent to the PTC thermistor in the current direction. When the number of the voltage-dividing resistor R2 is multiple, the multiple voltage-dividing resistors R2 are connected in series and are located between the PTC thermistor and the voltage-dividing resistor R3. At this time, the second voltage sampling port collects the voltage V2 between the PTC thermistor and the voltage-dividing resistor R2 adjacent to the PTC thermistor in the current direction. When there are multiple voltage-dividing resistors R3, the multiple voltage-dividing resistors R3 are connected in series and are all located on the downstream side of the PTC thermistor. At this time, the third voltage sampling port collects the voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3 adjacent to each other in the current direction.

[0024] In this embodiment, the PTC sampling circuit 2 also includes a capacitor C1, a capacitor C2 and a capacitor C3, one end of the capacitor C1 is connected to the connection point between the voltage-dividing resistor R1 and the PTC thermistor PTC, one end of the capacitor C2 is connected to the connection point between the PTC thermistor PTC and the voltage-dividing resistor R2, one end of the capacitor C3 is connected to the connection point between the voltage-dividing resistor R2 and the voltage-dividing resistor R3, and the other end of the capacitor C1, the other end of the capacitor C2 and the other end of the capacitor C3 are respectively connected to the negative pole of the power supply circuit.

[0025] In this embodiment, the PTC sampling circuit 2 also includes a current limiting resistor R4, a current limiting resistor R5 and a current limiting resistor R6. The current limiting resistor R4 is connected between the first voltage sampling port and the connection point between the voltage dividing resistor R1 and the PTC thermistor PTC, the current limiting resistor R5 is connected between the second voltage sampling port and the connection point between the PTC thermistor PTC and the voltage dividing resistor R2, and the current limiting resistor R6 is connected between the third voltage sampling port and the connection point between the voltage dividing resistor R2 and the voltage dividing resistor R3.

[0026] The single-chip microcomputer circuit 1 of the utility model includes a single-chip microcomputer U1 with an AD conversion function. The model of the single-chip microcomputer U1 is PIC12F1501. The VDD terminal of the single-chip microcomputer U1 is connected to the positive pole of the power supply circuit, the VSS terminal of the single-chip microcomputer U1 is connected to the negative pole of the power supply circuit, the AN0 terminal of the single-chip microcomputer U1 constitutes a first voltage sampling port, the AN1 terminal constitutes a second voltage sampling port, and the RA2 terminal constitutes a third voltage sampling port. The single-chip microcomputer circuit 1 also includes a capacitor C4, one end of which is connected to the VDD terminal of the single-chip microcomputer U1, and the other end of the capacitor C4 is connected to the negative pole of the power supply circuit. The negative pole of the power supply circuit is grounded, and the voltage of the positive pole of the power supply circuit is Figure 1 VCC in.

[0027] The utility model is a PTC motor temperature detection circuit. After the voltage VCC of the power supply circuit is divided by the voltage-dividing resistor R1, it is filtered by the capacitor C1 and limited by the current-limiting resistor R4, and then the upper end voltage V1 of the PTC thermistor PTC is sampled by the AN0 end of the single-chip computer U1. After the voltage VCC of the power supply circuit is divided by the PTC thermistor PTC, it is filtered by the capacitor C2 and limited by the current-limiting resistor R5, and then the lower end voltage V2 of the PTC thermistor PTC is sampled by the AN1 end of the single-chip computer U1. After the voltage VCC of the power supply circuit is divided by the voltage-dividing resistor R2, it is filtered by the capacitor C3 and limited by the current-limiting resistor R6, and then the voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3 is sampled by the RA2 end of the single-chip computer U1.

[0028] Therefore, the resistance value of the PTC thermistor PTC = (V1-V2) / ((V2-V3) / R12). Since the voltages V1, V2, and V3 are sampled by the single-chip microcomputer U1, when the temperature changes, V1, V2, and V3 change synchronously, and they are affected by the temperature in the same way. It can be considered that the temperature drift at this time is zero. Therefore, the resistance value of the PTC thermistor PTC is only related to the voltage divider resistor R2, and the resistance of the voltage divider resistor R2 is little affected by the temperature. Therefore, the utility model greatly reduces the temperature drift and can greatly improve the detection accuracy of the motor temperature.

[0029] After the single chip microcomputer U1 collects the three voltages V1, V2, and V3, the resistance of the PTC thermistor PTC is calculated according to the above-mentioned PTC thermistor PTC resistance calculation formula, and the temperature of the motor is fed back through the resistance of the PTC thermistor PTC. Therefore, the resistance of the PTC thermistor PTC can reflect the temperature of the motor, so that the single chip microcomputer U1 can output a corresponding control signal accordingly. This is the existing technology and will not be repeated here.

[0030] See also Figure 2 As shown, a motor control device of the utility model includes a relay for controlling the on and off of the circuit where the motor is located, and a relay control output circuit 3 connected to the relay; it also includes the PTC motor temperature detection circuit of the utility model as mentioned above, and the output of the single-chip microcomputer circuit 1 is connected to the relay control output circuit 3.

[0031] The motor control device of the utility model further includes a power input conversion circuit 4, which supplies power to the relay control output circuit 3, and the output of the power input conversion circuit 4 forms a power supply loop. Specifically, the power input conversion circuit 4 outputs a 5V voltage to the single-chip circuit 1 and the PTC sampling circuit 2, and at the same time, the power input conversion circuit 4 outputs a 24V voltage to the relay control output circuit 3.

[0032] The utility model provides a motor control device, wherein a single chip microcomputer U1 outputs different control signals to a relay control output circuit 3 according to the resistance value of a PTC thermistor PTC obtained, so that the relay control output circuit 3 controls the relay to disconnect the circuit where the motor is located when the resistance value of the PTC thermistor PTC is higher than a preset value, so that the motor stops working; and the relay control output circuit 3 controls the relay to connect or keep connected the circuit where the motor is located when the resistance value of the PTC thermistor PTC does not exceed the preset value, so that the motor is in a working state.

[0033] The utility model provides a PTC motor temperature detection circuit and a motor control device, and the unrelated parts are the same as the prior art or can be implemented by using the prior art.

[0034] The above embodiments are only used to further illustrate a PTC motor temperature detection circuit and a motor control device of the utility model, but the utility model is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model fall within the protection scope of the technical solution of the utility model.

Claims

1. A PTC motor temperature detection circuit, comprising a PTC sampling circuit, a single-chip microcomputer circuit for collecting voltage and outputting a control signal, wherein the PTC sampling circuit comprises a PTC thermistor for detecting the motor temperature; characterized in that: The PTC sampling circuit also includes at least one voltage-dividing resistor R1, at least one voltage-dividing resistor R2 and at least one voltage-dividing resistor R3. The voltage-dividing resistor R1, the PTC thermistor, the voltage-dividing resistor R2 and the voltage-dividing resistor R3 are sequentially connected in series in the power supply circuit along the flow direction of the current; the single-chip circuit has a first voltage sampling port, a second voltage sampling port and a third voltage sampling port. The first voltage sampling port collects the voltage V1 between the PTC thermistor and the voltage-dividing resistor R1, the second voltage sampling port collects the voltage V2 between the PTC thermistor and the voltage-dividing resistor R2, and the third voltage sampling port collects the voltage V3 between the voltage-dividing resistor R2 and the voltage-dividing resistor R3.

2. The PTC motor temperature detection circuit according to claim 1, characterized in that: The PTC sampling circuit also includes a capacitor C1, a capacitor C2 and a capacitor C3, one end of the capacitor C1 is connected to the connection point of the voltage-dividing resistor R1 and the PTC thermistor, one end of the capacitor C2 is connected to the connection point of the PTC thermistor and the voltage-dividing resistor R2, one end of the capacitor C3 is connected to the connection point of the voltage-dividing resistor R2 and the voltage-dividing resistor R3, and the other end of the capacitor C1, the other end of the capacitor C2 and the other end of the capacitor C3 are respectively connected to the negative electrode of the power supply circuit.

3. The PTC motor temperature detection circuit according to claim 1 or 2, characterized in that: The PTC sampling circuit also includes a current limiting resistor R4, a current limiting resistor R5 and a current limiting resistor R6. The current limiting resistor R4 is connected between the first voltage sampling port and the connection point between the voltage dividing resistor R1 and the PTC thermistor, the current limiting resistor R5 is connected between the second voltage sampling port and the connection point between the PTC thermistor and the voltage dividing resistor R2, and the current limiting resistor R6 is connected between the third voltage sampling port and the connection point between the voltage dividing resistor R2 and the voltage dividing resistor R3.

4. The PTC motor temperature detection circuit according to claim 3, characterized in that: The single-chip microcomputer circuit includes a single-chip microcomputer with an AD conversion function, the VDD terminal of the single-chip microcomputer is connected to the positive pole of the power supply circuit, the VSS terminal of the single-chip microcomputer is connected to the negative pole of the power supply circuit, the AN0 terminal of the single-chip microcomputer constitutes the first voltage sampling port, the AN1 terminal constitutes the second voltage sampling port, and the RA2 terminal constitutes the third voltage sampling port.

5. The PTC motor temperature detection circuit according to claim 4, characterized in that: The single-chip computer circuit further includes a capacitor C4, one end of which is connected to the VDD terminal of the single-chip computer, and the other end of which is connected to the negative electrode of the power supply circuit.

6. The PTC motor temperature detection circuit according to claim 4, characterized in that: The model of the single chip microcomputer is PIC12F1501.

7. The PTC motor temperature detection circuit according to claim 1 or 2 or 5 or 6, characterized in that: The negative pole of the power supply circuit is grounded.

8. A motor control device, comprising a relay for controlling the on / off of a circuit in which the motor is located, and a relay control output circuit connected to the relay; characterized in that: It also includes a PTC motor temperature detection circuit as described in any one of claims 1 to 7, characterized in that the output of the single-chip microcomputer circuit is connected to the relay control output circuit.

9. The motor control device according to claim 8, characterized in that: It also includes a power input conversion circuit, which supplies power to the relay control output circuit, and the output of the power input conversion circuit forms the power supply loop.

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