Protection circuit and motor device

Abstract

The utility model relates to a protection circuit and a motor device, the protection circuit comprises a sampling circuit, a comparison circuit and a switching circuit, when the motor is over-current, the sampling circuit samples the working current of the motor and converts the working current into a working voltage, the comparison circuit compares the working voltage with a reference voltage and generates a comparison signal, and the switching circuit outputs the comparison signal. When the switching circuit is in the on state, the switching circuit generates a first control signal, so that the comparison signal controls the switching circuit to be in the on state, and when the switching circuit is in the on state, the switching circuit generates a second control signal, so that the driving circuit generates a corresponding driving turn-off signal according to the second control signal to drive the motor to stop running, and overcurrent protection of the motor is realized. Therefore, the protection circuit can realize over-current protection of the motor, and generates a drive turn-off signal through hardware, thereby reducing time delay, effectively shortening protection time, and performing over-current protection in time, thereby improving the reliability of the motor device.

Description

Technical Field

[0001] The utility model relates to the field of motor protection, in particular to a protection circuit and a motor device. Background Art

[0002] For motor applications, it is necessary to protect the circuit and motor device to prevent overcurrent from causing damage to the circuit and motor. The current motor overcurrent protection solution is to sample the motor running current, and the MCU then processes and analyzes the sampled signal to protect the motor from overcurrent. However, the current overcurrent protection process takes a long time and cannot achieve the protection effect in time, which reduces the reliability of the motor device. Utility Model Content

[0003] The embodiments of the utility model aim to provide a protection circuit and a motor device, which can implement overcurrent protection for the motor, shorten the motor protection time, and improve the reliability of the motor device.

[0004] In order to solve the above technical problems, the present utility model provides the following technical solutions:

[0005] In a first aspect, an embodiment of the utility model provides a protection circuit, which is applied to a motor device, wherein the motor device includes a motor, a first controller, and a drive circuit, wherein the drive circuit is used to receive a first control signal sent by the first controller, and generate a corresponding drive signal according to the first control signal to drive the motor to operate, wherein the protection circuit includes: a sampling circuit, a comparison circuit, and a switch circuit;

[0006] The sampling circuit is connected to the first input terminal of the comparison circuit, and the working current of the motor flows through the sampling circuit. The sampling circuit is used to sample the working current of the motor and convert the working current into a working voltage;

[0007] The second input terminal of the comparison circuit is used to access the reference voltage, the output terminal of the comparison circuit is connected to the control terminal of the switch circuit, and the output terminal of the switch circuit is connected to the drive circuit;

[0008] When the motor has an overcurrent, the comparison circuit is used to compare the operating voltage with the reference voltage and generate a comparison signal, so that the comparison signal controls the switch circuit to be in a conducting state;

[0009] When the switch circuit is in the on state, the switch circuit is used to generate a second control signal, so that the drive circuit generates a corresponding drive shutdown signal according to the second control signal to drive the motor to stop running.

[0010] In some embodiments, the comparison circuit includes a voltage divider module and a comparator;

[0011] The non-inverting input terminal of the comparator is the first input terminal of the comparison circuit, which is used to receive the working voltage. The common connection point between the inverting input terminal of the comparator and the first end of the voltage divider module is the second input terminal of the comparison circuit. The output terminal of the comparator is the output terminal of the comparison circuit. The second end of the voltage divider module is connected to a DC power supply. The third end of the voltage divider module is grounded. The voltage divider module is used to divide the voltage of the DC power supply and generate the reference voltage.

[0012] In some embodiments, the voltage dividing module includes a first resistor and a second resistor;

[0013] One end of the first resistor is the second end of the voltage divider module, the common connection point between the other end of the first resistor and one end of the second resistor is the first end of the voltage divider module, and the other end of the second resistor is the third end of the voltage divider module.

[0014] In some embodiments, the switch circuit includes a MOS tube, the gate of the MOS tube is the control end of the switch circuit, the source of the MOS tube is grounded, and the drain of the MOS tube is the output end of the switch circuit.

[0015] In some embodiments, the protection circuit further includes a filter circuit;

[0016] The filter circuit is connected to the control end of the switch circuit and the output end of the comparison circuit respectively, and the filter circuit is used for filtering the comparison signal.

[0017] In some embodiments, the filtering circuit includes a third resistor and a filtering capacitor;

[0018] One end of the third resistor is respectively connected to one end of the filter capacitor, the control end of the switch circuit and the output end of the comparison circuit, and the other end of the third resistor and the other end of the filter capacitor are grounded.

[0019] In some embodiments, the sampling circuit includes a sampling resistor, the working current of the motor flows through the sampling resistor, and one end of the sampling resistor is connected to the first input end of the comparison circuit, and the other end of the sampling resistor is grounded to convert the working current into the working voltage.

[0020] In some embodiments, the output end of the comparison circuit is also connected to the first controller, and the first controller is used to receive the comparison signal and generate a third control signal based on the comparison signal, so that the drive circuit generates a corresponding drive shutdown signal according to the third control signal to drive the motor to stop running.

[0021] In some embodiments, the protection circuit further includes a second controller;

[0022] The second controller is connected to the output end of the comparison circuit and the drive circuit respectively. The second controller is used to receive the comparison signal and generate a fourth control signal according to the comparison signal, so that the drive circuit generates a corresponding drive shutdown signal according to the third and fourth control signals to drive the motor to stop running.

[0023] In a second aspect, an embodiment of the utility model provides a motor device, the motor device comprising: a motor, a first controller, a drive circuit and the protection circuit as described above;

[0024] The driving circuit is connected to the first controller and the motor respectively, and is used to receive a first control signal sent by the first controller, and generate a corresponding driving signal according to the first control signal to drive the motor to operate;

[0025] When the motor has an overcurrent, the protection circuit is used to stop the motor from running.

[0026] In various embodiments of the utility model, the protection circuit includes a sampling circuit, a comparison circuit and a switch circuit, wherein the sampling circuit is connected to the first input end of the comparison circuit, and the working current of the motor flows through the sampling circuit, the second input end of the comparison circuit is used to access the reference voltage, the output end of the comparison circuit is connected to the control end of the switch circuit, and the output end of the switch circuit is connected to the drive circuit. When the motor is overcurrent, the sampling circuit samples the working current of the motor and converts the working current into a working voltage. The comparison circuit compares the working voltage with the reference voltage and generates a comparison signal, so that the comparison signal controls the switch circuit to be in a conducting state, and when the switch circuit is in a conducting state, the switch circuit generates a second control signal, so that the drive circuit generates a corresponding drive shutdown signal according to the second control signal to drive the motor to stop running, so as to realize overcurrent protection of the motor. Therefore, the protection circuit can realize overcurrent protection of the motor, and it generates a drive shutdown signal through hardware, reduces delay, effectively shortens the protection time, and performs overcurrent protection in time, thereby improving the reliability of the motor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0028] Figure 1 It is a structural schematic diagram of a motor device provided by an embodiment of the utility model;

[0029] Figure 2 It is a structural schematic diagram of one of the protection circuits provided in the embodiment of the utility model;

[0030] Figure 3 It is a structural schematic diagram of one of the protection circuits provided in the embodiment of the utility model;

[0031] Figure 4 It is a structural schematic diagram of one of the protection circuits provided in the embodiment of the utility model;

[0032] Figure 5 It is a structural schematic diagram of one of the protection circuits provided in the embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0034] See also Figure 1 , Figure 1 Schematic diagram of the structure of a motor device provided by an embodiment of the present invention. Figure 1 As shown, the motor device 100 includes a motor 10, a first controller 20 and a drive circuit 30, wherein the drive circuit 30 is connected to the motor 10 and the first controller 20 respectively, and the drive circuit 30 can be a totem pole drive circuit composed of MOS tubes. The first controller 20 sends a first control signal to the drive circuit 30, and the first control signal acts on the drive circuit 30, so that the drive circuit 30 generates a corresponding drive signal, thereby driving the motor 10 to run or shut down.

[0035] The first control signal is a PWM wave signal, and the duty cycle of the PWM wave signal is controlled to control the running time of the motor 10. For example, when the PWM wave signal is at a high level, the drive circuit 30 generates a corresponding drive running signal to drive the motor 10 to run, and when the PWM wave signal is at a low level, the drive circuit 30 generates a corresponding drive shutoff signal to drive the motor 10 to shut off.

[0036] In order to implement overcurrent protection for the motor 10, the working current of the motor 10 can be sampled by a sampling device, and the working current is amplified by an operational amplifier and converted into a voltage signal, and then the voltage signal is transmitted to the first controller 20. The first controller 20 processes and analyzes the voltage signal, and when it is determined that the motor 10 has an overcurrent, the first control signal is controlled to a low level state, so that the drive circuit 30 generates a corresponding drive shutdown signal, and then drives the motor 10 to shut down, thereby implementing overcurrent protection for the motor 10.

[0037] When the overcurrent protection process takes a long time and is prone to delay, the protection effect cannot be achieved in time, thereby reducing the reliability of the motor device 100.

[0038] Based on the above reasons, an embodiment of the utility model provides a protection circuit, which is applied to the motor device 100, and can implement overcurrent protection for the motor 10, and effectively shorten the protection time and improve the reliability of the protection.

[0039] Specifically, see Figure 2 The protection circuit 40 includes a sampling circuit 401, a comparison circuit 402 and a switch circuit 403. The sampling circuit 401 is connected to a first input terminal of the comparison circuit 402, and the working current of the motor 10 flows through the sampling circuit 401. The second input terminal of the comparison circuit 402 is used to access a reference voltage. The output terminal of the comparison circuit 402 is connected to a control terminal of the switch circuit 403. The output terminal of the switch circuit 403 is connected to the drive circuit 30.

[0040] When the motor 10 is overcurrent, the sampling circuit 401 samples the working current of the motor 10 and converts the working current into a working voltage. The comparison circuit 402 compares the working voltage with the reference voltage and generates a comparison signal, so that the comparison signal controls the switch circuit 403 to be in the on state. When the switch circuit 403 is in the on state, the switch circuit 403 generates a second control signal, so that the drive circuit 30 generates a corresponding drive shutdown signal according to the second control signal to drive the motor 10 to stop running, thereby realizing overcurrent protection for the motor 10.

[0041] Therefore, the protection circuit can realize overcurrent protection for the motor, and it generates a drive shutdown signal through hardware, reduces the delay, effectively shortens the protection time, and thus improves the reliability of the motor device.

[0042] See also Figure 3 , Figure 3 Schematic diagram of a protection circuit provided by an embodiment of the utility model. Figure 3As shown, the comparison circuit 402 includes a voltage divider module 4021 and a comparator U1, wherein the non-inverting input terminal of the comparator U1 is the first input terminal of the comparison circuit 402, the common connection point between the inverting input terminal of the comparator U1 and the first terminal of the voltage divider module 4021 is the second input terminal of the comparison circuit 402, the output terminal of the comparator U1 is the output terminal of the comparison circuit 402, the second terminal of the voltage divider module 4021 is connected to a DC power supply, and the third terminal of the voltage divider module 4021 is grounded.

[0043] The non-inverting input terminal of the comparator U1 is used to receive the working voltage of the motor 10. The voltage divider module 4021 divides the voltage of the DC power supply and generates a reference voltage. The reference voltage acts on the inverting input terminal of the comparator U1. The comparator U1 compares the working voltage of the motor 10 with the reference voltage to generate a comparison signal.

[0044] When the motor 10 is not overcurrent, the working voltage of the motor 10 is less than the reference voltage, and the comparison signal output by the comparator U1 is a high level signal. When the motor 10 is overcurrent, the working voltage of the motor 10 is greater than the reference voltage, and the comparison signal output by the comparator U1 is a low level signal.

[0045] Since the reaction time of the comparator U1 is faster than the operational amplifier, compared with the technical solution using the operational amplifier, the protection circuit 40 can further shorten the protection time. In this embodiment, the model of the comparator is LM393.

[0046] In some embodiments, the protection circuit 40 also includes a filter circuit 404, which is respectively connected to the control end of the switch circuit 403 and the output end of the comparison circuit 402. The filter circuit 404 is used to filter the comparison signal, and the filtered comparison signal is transmitted to the control end of the switch circuit 403.

[0047] In some embodiments, Figure 3 As shown, the output end of the comparison circuit 402 is also connected to the first controller 20. The comparison signal output by the comparison circuit 402 is transmitted to the first controller 20, and the first controller 20 processes and analyzes the comparison signal. When it is determined that the motor 10 has an overcurrent, the first controller 20 generates a third control signal, and the third control signal acts on the drive circuit 30, so that the drive circuit 30 generates a corresponding drive shutdown signal, drives the motor 10 to stop running, and realizes overcurrent protection.

[0048] Therefore, the protection circuit 40 uses the hardware overcurrent protection and also uses the first controller 20 for a second protection, thereby achieving double protection and improving the reliability of protection. If the motor device 100 also uses a sampling device and an operational amplifier to achieve overcurrent protection, the motor device 100 can achieve triple protection.

[0049] In some embodiments, Figure 4 As shown, the protection circuit 40 further includes a second controller 405 , wherein the second controller 405 is connected to the output end of the comparison circuit 402 and the driving circuit 30 , respectively.

[0050] The comparison signal output by the comparison circuit 402 is transmitted to the second controller 405, and the second controller 405 processes and analyzes the comparison signal. When it is determined that an overcurrent occurs in the motor 10, the second controller 405 generates a fourth control signal, and the fourth control signal acts on the drive circuit 30, so that the drive circuit 30 generates a corresponding drive shutdown signal, drives the motor 10 to stop running, and realizes overcurrent protection.

[0051] This embodiment uses the second controller 405 to receive the comparison signal output by the comparison circuit 402. When the motor 10 has an overcurrent, the fourth control signal is used to control the drive circuit 30 to drive the motor 10 to stop running. Since the first controller 20 also needs to receive the sampling signal of the sampling device originally set, in order to avoid the first controller 20 from making an analysis error due to signal confusion, this embodiment implements overcurrent protection by additionally setting the second controller 405 to improve the protection reliability.

[0052] In the above embodiment, the models of the first controller 20 and the second controller 405 can be the same or different. The first controller 20 or the second controller 405 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component or any combination of these components. In addition, the first controller 20 or the second controller 405 can also be any traditional processor, controller, microcontroller or state machine. The first controller 20 or the second controller 405 can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP and / or any other such configuration.

[0053] See also Figure 5 , Figure 5 Schematic diagram of a circuit structure of a protection circuit provided by an embodiment of the utility model, such as Figure 5As shown, the voltage divider module 4021 includes a first resistor R1 and a second resistor R2, wherein one end of the first resistor R1 is the second end of the voltage divider module 4021, which is connected to a DC power supply, and a common connection point between the other end of the first resistor R1 and one end of the second resistor R2 is the first end of the voltage divider module 4021, which is connected to the inverting input end of the comparator U1, and the other end of the second resistor R2 is the third end of the voltage divider module 4021. In this embodiment, the voltage of the DC power supply is +5V.

[0054] The switch circuit 403 includes a MOS transistor Q, the gate of which is the control end of the switch circuit 403 and can be connected to the output end of the comparator U1 through a resistor R5, the source of the MOS transistor Q is grounded, and the drain of the MOS transistor Q is the output end of the switch circuit 403 and is connected to the drive circuit 30. In this embodiment, the MOS transistor Q is a PNPMOS transistor.

[0055] The filter circuit 404 includes a third resistor R3 and a filter capacitor C, one end of the third resistor R3 is respectively connected to one end of the filter capacitor C, the control end of the switch circuit 403 and the output end of the comparison circuit 402. Specifically, one end of the third resistor R3 is respectively connected to one end of the filter capacitor C, the output end of the comparator U1 and the gate of the MOS tube Q, and the other end of the third resistor R3 and the other end of the filter capacitor C are grounded.

[0056] The sampling circuit 401 includes a sampling resistor RS, the working current of the motor 10 flows through the sampling resistor RS, and one end of the sampling resistor RS is connected to the first input end of the comparison circuit 402. Specifically, one end of the sampling resistor RS can be connected to the in-phase input end of the comparator U1 via the resistor R4, and the other end of the sampling resistor RS is grounded to convert the working current into the working voltage.

[0057] Combination Figure 5 , the working principle of the protection circuit 40 can be described as follows:

[0058] The working current of the motor 10 flows through the sampling resistor RS, and the sampling resistor RS converts the working current into a working voltage. The comparator U1 compares the working voltage with the reference voltage and outputs a comparison signal Over_CUR;

[0059] When the motor 10 is not overcurrented, the operating voltage is less than the reference voltage, the comparison signal output by the comparator U1 is a high level signal, and the MOS tube Q is in a cut-off state;

[0060] When overcurrent occurs in the motor 10, the operating voltage is greater than the reference voltage, the comparison signal Over_CUR output by the comparator U1 is a low-level signal, the MOS tube Q is in the on state, and the drain of the MOS tube Q is a low-level signal, which acts on the drive circuit 30, so that the drive circuit 30 generates a corresponding drive shutdown signal, drives the motor 10 to stop running, and realizes overcurrent protection.

[0061] The comparison signal Over_CUR can also be transmitted to the first controller 20 or the second controller 405 (the figure shows the transmission to the second controller 405 as an example), so that the first controller 20 or the second controller 405 generates a second control signal or a third control signal according to the comparison signal, and then the drive circuit 30 generates a corresponding drive shutdown signal, driving the motor 10 to stop running, thereby realizing double overcurrent protection.

[0062] In summary, the protection circuit can realize overcurrent protection for the motor, and it generates a drive shutdown signal through hardware, reduces the delay, effectively shortens the protection time, and thus improves the reliability of the motor device.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A protection circuit applied to a motor device, the motor device comprising a motor, a first controller and a drive circuit, the drive circuit being used to receive a first control signal sent by the first controller and generate a corresponding drive signal according to the first control signal to drive the motor to operate, characterized in that: The protection circuit comprises: a sampling circuit, a comparison circuit and a switch circuit; The sampling circuit is connected to the first input terminal of the comparison circuit, and the working current of the motor flows through the sampling circuit. The sampling circuit is used to sample the working current of the motor and convert the working current into a working voltage; The second input terminal of the comparison circuit is used to access the reference voltage, the output terminal of the comparison circuit is connected to the control terminal of the switch circuit, and the output terminal of the switch circuit is connected to the drive circuit; When the motor has an overcurrent, the comparison circuit is used to compare the operating voltage with the reference voltage and generate a comparison signal, so that the comparison signal controls the switch circuit to be in a conducting state; When the switch circuit is in the on state, the switch circuit is used to generate a second control signal, so that the drive circuit generates a corresponding drive shutdown signal according to the second control signal to drive the motor to stop running.

2. The protection circuit according to claim 1, characterized in that: The comparison circuit includes a voltage divider module and a comparator; The non-inverting input terminal of the comparator is the first input terminal of the comparison circuit, which is used to receive the working voltage. The common connection point between the inverting input terminal of the comparator and the first end of the voltage divider module is the second input terminal of the comparison circuit. The output terminal of the comparator is the output terminal of the comparison circuit. The second end of the voltage divider module is connected to a DC power supply. The third end of the voltage divider module is grounded. The voltage divider module is used to divide the voltage of the DC power supply and generate the reference voltage.

3. The protection circuit according to claim 2, characterized in that: The voltage dividing module includes a first resistor and a second resistor; One end of the first resistor is the second end of the voltage divider module, the common connection point between the other end of the first resistor and one end of the second resistor is the first end of the voltage divider module, and the other end of the second resistor is the third end of the voltage divider module.

4. The protection circuit according to claim 1, characterized in that: The switch circuit comprises a MOS tube, a gate of the MOS tube is a control end of the switch circuit, a source of the MOS tube is grounded, and a drain of the MOS tube is an output end of the switch circuit.

5. The protection circuit according to claim 1, characterized in that: The protection circuit also includes a filter circuit; The filter circuit is connected to the control end of the switch circuit and the output end of the comparison circuit respectively, and the filter circuit is used for filtering the comparison signal.

6. The protection circuit according to claim 5, characterized in that: The filtering circuit includes a third resistor and a filtering capacitor; One end of the third resistor is respectively connected to one end of the filter capacitor, the control end of the switch circuit and the output end of the comparison circuit, and the other end of the third resistor and the other end of the filter capacitor are grounded.

7. The protection circuit according to claim 1, characterized in that: The sampling circuit includes a sampling resistor, the working current of the motor flows through the sampling resistor, one end of the sampling resistor is connected to the first input end of the comparison circuit, and the other end of the sampling resistor is grounded to convert the working current into the working voltage.

8. The protection circuit according to any one of claims 1 to 7, characterized in that: The output end of the comparison circuit is also connected to the first controller, which is used to receive the comparison signal and generate a third control signal according to the comparison signal, so that the drive circuit generates a corresponding drive shutdown signal according to the third control signal to drive the motor to stop running.

9. The protection circuit according to any one of claims 1 to 7, characterized in that: The protection circuit also includes a second controller; The second controller is connected to the output end of the comparison circuit and the drive circuit respectively. The second controller is used to receive the comparison signal and generate a fourth control signal according to the comparison signal, so that the drive circuit generates a corresponding drive shutdown signal according to the fourth control signal to drive the motor to stop running.

10. A motor device, characterized in that: The motor device comprises: a motor, a first controller, a drive circuit and a protection circuit as claimed in any one of claims 1 to 9; The driving circuit is connected to the first controller and the motor respectively, and is used to receive a first control signal sent by the first controller, and generate a corresponding driving signal according to the first control signal to drive the motor to operate; When the motor has an overcurrent, the protection circuit is used to stop the motor from running.

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