CN112134496A - DC motor locked-rotor detection module and method and motor driving device - Google Patents

Abstract

The invention discloses a DC motor locked-rotor detection module and a method thereof, and a motor driving device; the module comprises: the sampling part is arranged on an alternating current power supply loop of the direct current motor and is used for sampling the motor power supply current flowing through the alternating current power supply loop and converting the motor power supply current into sampling voltage; and an electrical isolation section for electrically isolating the sampling voltage from the locked rotor detection signal; the locked rotor detection signal comprises a first detection signal and a second detection signal; if the power supply current of the motor does not exceed a preset current, the electric isolation part provides the first detection signal; and if the motor power supply current exceeds the preset current, the electrical isolation part provides the second detection signal. The invention has the advantages of electric isolation and high safety.

Description

DC motor locked-rotor detection module and method and motor driving device

Technical Field

The invention relates to the technical field of electronics, in particular to a direct current motor locked-rotor detection module and method and a motor driving device.

Background

The direct current motor is widely applied in production and life, and the operation reliability of the direct current motor directly determines whether the working state of electrical equipment applying the direct current motor is good or not. The locked rotor refers to the condition that the motor still outputs torque when the rotating speed is 0 revolution, and if the locked rotor occurs when the direct current motor operates, the current flowing through the direct current motor is large, so that the motor is easily damaged and the electrical equipment is easily damaged. Therefore, the locked rotor detection of the direct current motor is beneficial to determining whether the motor is locked rotor or not and further protecting when the locked rotor is determined to be generated, and the locked rotor detection is very necessary to guarantee the reliability of the direct current motor.

The direct current motor lock-rotor detection mode in the prior art has the following problems: the locked rotor detection loop is not electrically isolated, and the product has potential safety hazards.

Disclosure of Invention

The invention provides a direct current motor locked rotor detection module with electrical isolation and high safety, a corresponding direct current motor locked rotor detection method and a motor driving device with the direct current motor locked rotor detection module.

The invention adopts a technical means that: the utility model provides a DC motor locked rotor detection module includes:

the sampling part is arranged on an alternating current power supply loop of the direct current motor and is used for sampling the motor power supply current flowing through the alternating current power supply loop and converting the motor power supply current into sampling voltage; and

an electrical isolation section for electrically isolating the sampling voltage from a locked-rotor detection signal; the locked rotor detection signal comprises a first detection signal and a second detection signal; if the power supply current of the motor does not exceed a preset current, the electric isolation part provides the first detection signal; and if the motor power supply current exceeds the preset current, the electrical isolation part provides the second detection signal.

The invention adopts another technical means that: provided is a motor drive device including:

the alternating current power supply loop is used for outputting alternating current;

the direct current power supply loop is used for receiving the alternating current and converting the alternating current into direct current to supply to the direct current motor;

the direct current motor locked rotor detection module; and

and the power supply control execution part is connected with the motor control part and the alternating current power supply loop and is used for controlling the on-off of the alternating current power supply loop according to the power supply control signal output by the motor control part.

The invention adopts another technical means that: the method for detecting the locked rotor of the direct current motor comprises the following steps:

sampling the motor power supply current flowing through the alternating current power supply loop of the direct current motor, and converting the sampled voltage into sampled voltage;

if the power supply current of the motor does not exceed the preset current, providing a first detection signal; if the motor power supply current exceeds the preset current, providing a second detection signal; the first detection signal and the second detection signal both belong to locked rotor detection signals, and the locked rotor detection signals are electrically isolated from the sampling voltage.

By adopting the technical scheme, the direct current motor locked rotor detection module, the method and the motor driving device thereof provided by the invention have the advantages that the locked rotor detection of the direct current motor can be realized by the matching of the sampling part and the electrical isolation part, and meanwhile, the obtained locked rotor detection signal is electrically isolated from the locked rotor detection circuits such as the sampling part and the like, so that the potential safety hazard caused by the common grounding of the sampling part connected with strong current and the control part connected with weak current is favorably avoided, the safety is high, and the reliability of the direct current motor is effectively improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Wherein:

FIG. 1 is a block diagram of a DC motor stall detection module in one embodiment;

FIG. 2 is a block diagram of a DC motor stall detection module in one embodiment;

FIG. 3 is a block diagram of a DC motor stall detection module in one embodiment;

FIG. 4 is a block diagram showing the structure of a motor driving device according to an embodiment;

FIG. 5 is a block diagram showing the structure of a motor driving device according to an embodiment;

FIG. 6 is a schematic circuit diagram of an embodiment of a DC motor stall detection module and a motor drive;

fig. 7 is a flow chart of a dc motor stall detection method in one embodiment.

In the figure: 1. the device comprises a direct current motor locked-rotor detection module, 2, an alternating current power supply circuit, 3, a direct current power supply circuit, 4, a power supply control execution part, 5, a forward and reverse rotation control execution part, 6, a direct current motor, 11, a sampling part, 12, an electrical isolation part, 13, an amplification part, 14, a motor control part, 15, a power supply part, 21, a first alternating current power supply branch, 22, a second alternating current power supply branch, 23, a first alternating current input end, 24, a second alternating current input end, 31, a rectification part, 32, a first direct current power supply branch, 33, a second direct current power supply branch, 41, a first switch control module, 42, a first controllable switch, 51, a second switch control module, 52, a second controllable switch, 121, a light emitting module, 122 and a light receiving module.

Detailed Description

In order to make the objects, technical solutions and technical effects of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and the detailed description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

The invention provides a dc motor locked-rotor detection module 1, as shown in fig. 1, in an embodiment, the module may include: a sampling part 11 and an electrical isolation part 12. The sampling unit 11 is provided in the ac power supply circuit 2 of the dc motor 6. The power supply circuit of the dc motor 6 includes an ac power supply circuit 2 and a dc power supply circuit 3, the input ac power can be supplied to the dc power supply circuit 3 via the ac power supply circuit 2, and the dc power supply circuit 3 performs ac-dc conversion to supply the dc power required for its operation to the dc motor 6.

In this embodiment, the sampling unit 11 is configured to sample the motor supply current flowing through the ac power supply circuit 2 and convert the sampled current into a sampling voltage, when the motor supply current flowing through the ac power supply circuit 2 is large, correspondingly, the sampling voltage is also large, when the motor supply current flowing through the ac power supply circuit 2 is small, correspondingly, the sampling voltage is also small, and the sampling voltage output by the sampling unit 11 can directly obtain the condition of the motor supply current flowing through the ac power supply circuit 2.

The electrical isolation unit 12 is configured to electrically isolate the sampling voltage from the locked rotor detection signal, and the generation and output loop of the sampling voltage and the generation and output loop of the locked rotor detection signal are electrically isolated from each other and independently grounded. The electrical isolation part 12 is further configured to generate a locked-rotor detection signal based on a condition of a motor supply current flowing through the ac power supply loop 2, where the motor supply current when the dc motor 6 is locked-rotor will exceed a motor supply current required by the dc motor 6 during normal operation. The locked rotor detection signal comprises a first detection signal and a second detection signal. If the motor supply current does not exceed a preset current, the electrical isolation part 12 provides the first detection signal. If the motor supply current exceeds the preset current, the electrical isolation part 12 provides the second detection signal. The preset current is set according to a motor supply current range required by the dc motor 6 during normal operation, and illustratively, the preset current may take a maximum motor supply current required by the dc motor 6 during normal operation. The electrical isolation portion 12 may be an optoelectronic isolation component, a magnetic electrical isolation component, or other isolation components that can achieve electrical isolation. Can be earlier according to through electrical isolation portion 12 sampling voltage or right the voltage that sampling voltage carries out signal processing back and obtains confirms whether carry out photoelectric conversion or electromagnetic conversion etc. then transmission light signal or magnetic signal give stifled commentaries on classics detection signal's generation end, stifled commentaries on classics detection signal's generation end further carries out photoelectric conversion or magnetoelectric conversion, or does not carry out photoelectric conversion or magnetoelectric conversion, and then the generation form is the signal of telecommunication stifled commentaries on classics detection signal to whether carry out photoelectric conversion or magnetoelectric conversion will correspond the difference stifled commentaries on classics detection signal.

The direct current motor locked rotor detection module 1 of the embodiment can realize locked rotor detection of the direct current motor 6 through the matching of the sampling part 11 and the electrical isolation part 12, and simultaneously electrically isolates an obtained locked rotor detection signal from locked rotor detection circuits such as sampling circuits, thereby being beneficial to avoiding potential safety hazards caused by the common grounding of the sampling part 11 connected with strong current and the control part connected with weak current.

In one embodiment, as shown in fig. 2, the module may further include an amplifying section 13. The amplifying part 13 is disposed between the sampling part 11 and the electrical isolation part 12, and is configured to amplify the sampled voltage to obtain a sampled and amplified voltage, and transmit the sampled and amplified voltage to the electrical isolation part 12. The electrical isolation unit 12 may directly receive the sampled voltage output by the sampling unit 11, or may receive the sampled amplified voltage obtained by amplifying the sampled voltage in consideration of the driving condition of the electrical isolation unit 12. When the electrical isolation unit 12 is connected to the sampling unit 11 via the amplification unit 13, the electrical isolation unit 12 is configured to electrically isolate the sampling unit 11 from the stall detection signal generation and output circuit, and to electrically isolate the amplification unit 13 from the stall detection signal generation and output circuit, the sampling unit 11 and the amplification unit 13 being connected in common, and the sampling unit 11 and the amplification unit 13 being connected in non-common with the stall detection signal generation and output circuit.

Further, the electrical isolation portion 12 may adopt an optoelectronic isolation component, that is, the sampling portion 11 and the amplifying portion 13 are isolated from the locked-rotor detection signal and the output loop by the optoelectronic isolation, and the optoelectronic isolation manner may be adopted to achieve good isolation performance between strong current and weak current, and the hardware cost is not high. The optoelectronic isolation assembly has a light emitting module 121 and a light receiving module 122. The optical transmitting module 121 is connected to the first ground terminal, and is configured to be controlled by the sampled and amplified voltage to determine whether to transmit an optical signal, and the optical transmitting module 121 determines whether to perform an electrical-to-optical conversion according to a magnitude of the sampled and amplified voltage. The light receiving module 122 is connected to a second ground terminal, and configured to output the first detection signal or the second detection signal based on whether the optical signal is received. The first grounding end and the second grounding end are two independent grounding ends which are not grounded together.

Further, the light emitting module 121 may have an on state and an off state, and emit the light signal when in the on state and not emit the light signal when in the off state. Further, in a case where the sampled and amplified voltage drives the light emitting module 121 to be in a conducting state, the light emitting module 121 emits the optical signal. When the optical transmitting module 121 is not in the on state, that is, in the off state, the optical transmitting module 121 does not transmit the optical signal, so that whether the optical transmitting module 121 performs conversion of converting the electrical signal into the optical signal according to the magnitude of the sampled and amplified voltage is realized.

Further, exemplarily, referring to fig. 6, the amplifying part 13 may be an inverse amplifying module including a resistor R6, a resistor R7, a resistor R8, a resistor R9, and an operational amplifier U2. One end of the resistor R7 is connected with the sampling resistor R3, and the other end is connected with the inverting input end of the operational amplifier U2. The two ends of the resistor R8 are respectively connected to the inverting input terminal and the output terminal of the operational amplifier U2, and the output terminal of the operational amplifier U2 outputs the sampled and amplified voltage obtained by the amplifying unit 13 via the resistor R9. The non-inverting input terminal of the operational amplifier U2 is connected to the first ground terminal through a resistor R6.

Further, the light receiving module 122 may have an on state and an off state. When the light receiving module 122 is in the on state, the light receiving module 122 outputs the second detection signal, which indicates that the motor supply current in the ac power supply loop 2 of the dc motor 6 exceeds the preset current, and the dc motor 6 is locked. When the light receiving module 122 is in an off state, the light receiving module 122 outputs the first detection signal, which indicates that the motor supply current in the ac power supply loop 2 of the dc motor 6 does not exceed the preset current, and the dc motor 6 does not stall during normal operation. Further, when the light receiving module 122 receives the optical signal, the optical signal makes the light receiving module 122 in an on state, and the light receiving module 122 outputs the second detection signal. In a case where the light receiving module 122 does not receive the light signal, the light receiving module 122 maintains an off state, and the light receiving module 122 outputs the first detection signal. The first detection signal and the second detection signal may be detection signals having different signal logic states so that the control section receiving the locked rotor detection signal can more clearly distinguish the first detection signal from the second detection signal. For example, the second detection signal is at a low logic level and the first detection signal is at a high logic level, but of course, the second detection signal may be at a high logic level and the first detection signal may be at a low logic level as needed. For example, in the circuit schematic diagram of the dc motor stalling detection module 1 shown in fig. 6, a network reference IO3 represents the stalling detection signal, wherein the second detection signal is at a low logic level, and the first detection signal is at a high logic level.

In one embodiment, as shown with reference to fig. 3, the module may further include a motor control 14. The motor control part 14 is connected to the electrical isolation part 12, and is configured to receive the locked rotor detection signal and control whether the ac power supply loop 2 supplies power to the dc motor 6. The motor control part 14 can control whether the alternating current power supply loop 2 supplies power to the direct current motor 6 based on the received locked rotor detection signal, so that the power supply loop of the direct current motor 6 can adjust power supply in time according to the condition whether the locked rotor occurs to the motor, the locked rotor condition of the motor can be cut off, and the damage of the direct current motor 6 and electrical equipment caused by long duration time of the locked rotor of the motor can be avoided. Of course, the motor control unit 14 may also prompt the user that the received locked rotor detection signal is valid, for example, when it is determined that the dc motor 6 is locked, the motor locked rotor information is prompted to the user in a display or transmission manner, and before the user makes a control instruction related to the power supply loop, the motor control unit 14 continues to maintain the original power supply control on the ac power supply loop 2, that is, the motor control unit 14 may control whether the ac power supply loop 2 supplies power to the dc motor 6 based on whether the dc motor 6 is locked rotor, or may control the ac power supply loop 2 without based on the locked rotor condition of the dc motor 6, and the control whether the ac power supply loop 2 supplies power to the dc motor 6 may be independent of the locked rotor condition of the dc motor 6.

The motor control unit 14 according to this embodiment may be a single chip, a microcontroller, a processor, or other control units with equivalent functions. For example, in a schematic circuit diagram of the dc motor stalling detection module 1 shown in fig. 6, the motor control unit 14 is a single chip Microcomputer (MCU). The motor control part 14 can integrate the positive and negative rotation control functions of the direct current motor 6 besides the locked rotor detection and the motor power supply control, integrates the detection and control functions related to the direct current motor 6, and is beneficial to the unified control of the motor and the saving of hardware cost.

In one embodiment, as shown with reference to fig. 3, the module may further include a power supply section 15. The power supply part 15 is used for supplying a first power supply and a second power supply; the output end of the first power supply comprises a first power supply end and the first grounding end; the first power supply is used for supplying power to the amplifying part 13 and the light emitting module 121, and the sampling part 11 is also connected with the first ground terminal; the output end of the second power supply comprises a second power supply end and a second grounding end; the second power supply is used for supplying power to the light receiving module 122 and the motor control unit 14. For example, as shown in fig. 6, the power supply unit 15 may include a rectifying module for receiving an input ac power, and a switching power supply connected to the rectifying module. The rectifying module shown in fig. 6 includes rectifying diodes D1 to D4. The first power supply and the second power supply are provided by the switching power supply, the switching power supply shown in fig. 6 is a DC-DC power supply module, V1 denotes a first power supply terminal, V2 denotes a second power supply terminal, GND1 denotes a first ground terminal, and GND2 denotes a second ground terminal in fig. 6. Of course, the power supply part 15 may also adopt an AC-DC power supply module that directly receives an input alternating current, and the first power supply and the second power supply are provided by the AC-DC power supply module.

In one embodiment, referring to fig. 6, the sampling unit 11 may include a sampling resistor connected in series to the ac power supply circuit 2, and one end of the sampling resistor is connected to a first ground terminal. The optoelectronic isolation component may include a threshold diode, a shunt resistor, a photocoupler, and a pull-up resistor. The photoelectric coupler is provided with a light emitting diode and a phototriode, and the photoelectric coupler can also be provided with other photoelectric structures which can replace the light emitting diode and the phototriode. The bypass resistor is connected in parallel with the light emitting diode. The cathode of the threshold diode is connected to the amplifying part 13, the anode of the threshold diode is connected to the anode of the light emitting diode, and the cathode of the light emitting diode is connected to the first ground terminal. The collector of the phototriode is connected with the second power end through the pull-up resistor, and the emitter of the phototriode is connected with the second grounding end. Wherein the threshold diode, the shunt resistor and the light emitting diode constitute the light emitting module 121. The photo transistor and the pull-up resistor constitute the light receiving module 122. The sampled amplified voltage obtained by amplifying the sampled voltage by the amplifying part 13 is input to the optoelectronic isolation component from the cathode of the threshold diode.

The present invention further provides a motor driving apparatus, and in one embodiment, referring to fig. 4, the apparatus may include an ac power supply circuit 2, a dc power supply circuit 3, a dc motor stalling detection module 1 according to any of the above embodiments, and a power supply control execution unit 4. The alternating current power supply loop 2 is used for outputting alternating current. The dc power supply circuit 3 is configured to receive the ac power and convert the ac power into dc power to supply to the dc motor 6.

In this embodiment, the power supply control executing unit 4 is connected to the motor control unit 14 and the ac power supply circuit 2, and is configured to control on/off of the ac power supply circuit 2 according to a power supply control signal output by the motor control unit 14, when the ac power supply circuit 2 is turned off, the ac power supply circuit 2 does not supply power to the dc motor 6, and when the ac power supply circuit 2 is turned on, the ac power supply circuit 2 supplies power to the dc motor 6. The power supply control signal may include a first control signal and a second control signal, the ac power supply circuit 2 is turned on when the power supply control execution part 4 outputs the first control signal, and the ac power supply circuit 2 is turned off when the power supply control execution part 4 outputs the second control signal. The first control signal and the second control signal may be control signals with different signal logic states, for example, the first control signal is a high logic level, and the second control signal is a low logic level. In the circuit schematic diagram of the dc motor stalling detection module 1 shown in fig. 6, a network reference number IO2 represents the power supply control signal, where the first control signal is at a high logic level, and the second control signal is at a low logic level.

In an embodiment, referring to fig. 4, when the motor control unit 14 receives the second detection signal, which indicates that the dc motor 6 is locked, the motor control unit 14 may control the ac power supply circuit 2 to be disconnected via the power supply control executing unit 4, so as to cut off power supply to the ac power supply circuit 2 when the dc motor 6 is locked, and thus, a problem caused by long-time locking of the dc motor 6 may be effectively avoided.

In one embodiment, as shown with reference to fig. 4, the power supply control execution part 4 may include a first switch control module 41 and a first controllable switch 42. The first switch control module 41 is configured to control a switching state of the first controllable switch 42 based on the received power supply control signal. The first controllable switch 42 is connected to the first switch control module 41, and is configured to switch a switch state thereof to control on/off of the ac power supply loop 2. When the first switch control module 41 receives the first control signal, it controls the first controllable switch 42 to be in the on state, and when the first controllable switch 42 is in the on state, the ac power supply loop 2 is turned on. When the first switch control module 41 receives the second control signal, it controls the first controllable switch 42 to be in the off state, and when the first controllable switch 42 is in the off state, the ac power supply loop 2 is disconnected. The embodiment realizes the power supply control of the direct current motor 6 through a hardware structure which is convenient to control and low in cost.

Illustratively, referring to fig. 6, the first switch control module 41 includes: a resistor R1, a resistor R2 and a switch tube Q1. The power supply control signal IO2 drives the switching tube Q1 via the resistor R1, the switching tube Q1 may be a transistor, a MOS transistor, or another electronic switching tube, the switching tube Q1 shown in fig. 6 is a transistor, the resistor R2 is connected between the base and the emitter of the switching tube Q1, and the emitter of the switching tube Q1 is connected to the second ground terminal.

In one embodiment, as shown with reference to fig. 4 and 6, the ac supply circuit 2 may comprise a first ac supply branch 21 connected to a first ac input 23 and a second ac supply branch 22 connected to a second ac input 24. The first controllable switch 42 may comprise a first relay. The first relay has a first coil, and a first stationary contact 1s and a first movable contact 1m provided in the first ac power supply branch 21 or the second ac power supply branch 22. One end of the first coil is connected to the second power source end, and the other end of the first coil is connected to the first switch control module 41, specifically, the other end of the first coil is connected to a collector of a switch Q1. The first stationary contact 1s is connected to the first ac input terminal 23 or the second ac input terminal 24, and the first movable contact 1m is connected to a second ground terminal via the sampling unit 11. Referring to fig. 6, a diode D5 is also connected in parallel to both ends of the first coil. First ac input end 23 can be the port of being connected with the live wire, second ac input end 24 can be the port of being connected with the zero line, ac power supply circuit 2 can be the relevant power supply circuit of direct input commercial power, also can be the relevant power supply circuit of carrying out the interchange transformation to the input commercial power, for example, can contain the transformer in ac power supply circuit 2, first ac input end 23 and second ac input end 24 that show in fig. 6 are respectively for the port L of being connected with the live wire and the port N of being connected with the zero line promptly.

In one embodiment, as shown with reference to fig. 5, the module may further include a forward and reverse rotation control executing section 5. The forward/reverse rotation control executing part 5 is connected to the motor control part 14 and the dc power supply loop 3, and is configured to control the polarity of the voltage across the dc motor 6 according to the forward/reverse rotation control signal output by the motor control part 14, so as to switch the forward rotation and the reverse rotation of the dc motor 6. The forward and reverse control signal may include a forward control signal and a reverse control signal, and when the forward and reverse control executing portion 5 outputs the forward control signal, the polarity of the voltage across the dc motor 6 is positive, and the dc motor 6 rotates forward. When the forward/reverse rotation control executing unit 5 outputs a reverse rotation control signal, the polarity of the voltage across the dc motor 6 is negative, and the dc motor 6 reverses. The forward rotation control signal and the reverse rotation control signal may be control signals with different signal logic states, for example, the forward rotation control signal is at a high logic level, and the reverse rotation control signal is at a low logic level. In the circuit schematic diagram of the dc motor locked-rotor detection module 1 shown in fig. 6, a network reference number IO1 represents the forward/reverse rotation control signal, where the forward rotation control signal is at a high logic level and the reverse rotation control signal is at a low logic level.

In one embodiment, referring to fig. 5, the forward/reverse rotation control executing part 5 may include a second switch control module 51 and a second controllable switch 52. The second switch control module 51 is configured to control an operating state of the second controllable switch 52 based on the received forward/reverse control signal. The second controllable switch 52 is connected to the second switch control module 51, and is controlled by the forward/reverse control signal to adjust the connection between the dc power supply loop 3 and the dc motor 6, so as to change the polarity of the voltage across the dc motor 6 to positive polarity or negative polarity.

Exemplarily, referring to fig. 6, the second switch control module 51 includes: a resistor R4, a resistor R5 and a switch tube Q2. The forward/reverse rotation control signal IO1 drives the switching tube Q2 via the resistor R4, the switching tube Q2 may be a transistor, a MOS transistor, or another electronic switching tube, the switching tube Q2 shown in fig. 6 is a transistor, the resistor R5 is connected between the base and the emitter of the switching tube Q2, and the emitter of the switching tube Q2 is connected to the second ground terminal.

In one embodiment, as shown with reference to fig. 5 and 6, the dc supply circuit 3 may include a rectifying component 31, a first dc supply branch 32 and a second dc supply branch 33. The input end of the rectifying component 31 is connected to the ac power supply circuit 2, and the output end of the rectifying component 31 is connected to the dc motor 6 via the first dc power supply branch 32 and the second dc power supply branch 33. The rectifying unit 31 performs ac-dc conversion on the ac power provided by the ac power supply circuit 2, and then provides dc power to the dc motor 6 through the first dc power supply branch 32 and the second dc power supply branch 33. Illustratively, referring to fig. 6, the rectifying component 31 may employ a rectifying bridge BD 1.

Further, the second controllable switch 52 may comprise a second relay. The second relay has a second coil, a second movable contact 2m, a third movable contact 3m, a second stationary contact 2s, a third stationary contact 3s, a fourth stationary contact 4s, and a fifth stationary contact 5 s. One end of the second coil is connected to the second switch control module 51, specifically, one end of the second coil is connected to a collector of the switching tube Q2, and the other end of the second coil is connected to the second power supply end. And a diode D6 is connected in parallel with two ends of the second coil. The second movable contact 2m, the second stationary contact 2s, and the fifth stationary contact 5s are all provided on the first dc power supply branch 32. The third moving contact 3m, the third stationary contact 3s, and the fourth stationary contact 4s are all disposed on the second dc power supply branch 33. The second movable contact 2m can be brought into contact with the second stationary contact 2s or the third stationary contact 3s, and the third movable contact 3m can be brought into contact with the fourth stationary contact 4s or the fifth stationary contact 5 s. Because the first dc power supply branch 32 and the second dc power supply branch 33 are respectively connected to the positive output terminal and the negative output terminal of the rectifying component 31, when the first dc power supply branch 32 is connected to the positive pole of the dc motor 6 and the second dc power supply branch 33 is connected to the negative pole of the dc motor 6, the dc motor 6 rotates forward, and when the first dc power supply branch 32 is connected to the negative pole of the dc motor 6 and the second dc power supply branch 33 is connected to the positive pole of the dc motor 6, the dc motor 6 rotates backward. The connection control between the first direct current power supply branch 32 and the second direct current power supply branch 33 and the positive pole and the negative pole of the direct current motor 6 is realized by controlling the second stationary contact 2s or the third stationary contact 3s communicated with the second movable contact 2m and controlling the fourth stationary contact 4s or the fifth stationary contact 5s communicated with the third movable contact 3m, so that the switching between the positive rotation and the reverse rotation of the direct current motor 6 is realized.

The present invention further provides a method for detecting a locked rotor of a dc motor, as shown in fig. 7, in an embodiment, the method may include the following steps:

and step S1, sampling the motor power supply current flowing through the direct current motor alternating current power supply loop, and converting the current into sampling voltage.

Step S2, if the power supply current of the motor does not exceed the preset current, a first detection signal is provided; the first detection signal belongs to a locked rotor detection signal, and the locked rotor detection signal is electrically isolated from the sampling voltage.

Step S3, if the power supply current of the motor exceeds the preset current, a second detection signal is provided; the second detection signal belongs to a locked rotor detection signal, and the locked rotor detection signal is electrically isolated from the sampling voltage.

The direct current motor locked-rotor detection module, the method thereof and the motor driving device can be suitable for household appliances such as an electric oven, a range hood and the like, and can also be used in other occasions using the direct current motor.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims (14)

1. The utility model provides a DC motor stalling detection module which characterized in that, the module includes:

the sampling part is arranged on an alternating current power supply loop of the direct current motor and is used for sampling the motor power supply current flowing through the alternating current power supply loop and converting the motor power supply current into sampling voltage; and

an electrical isolation section for electrically isolating the sampling voltage from a locked-rotor detection signal; the locked rotor detection signal comprises a first detection signal and a second detection signal; if the power supply current of the motor does not exceed a preset current, the electric isolation part provides the first detection signal; and if the motor power supply current exceeds the preset current, the electrical isolation part provides the second detection signal.

2. The DC motor stall detection module of claim 1,

the module further comprises: the amplifying part is arranged between the sampling part and the electric isolating part and is used for amplifying the sampling voltage to obtain a sampling amplified voltage and transmitting the sampling amplified voltage to the electric isolating part;

the electrical isolation part adopts a photoelectric isolation assembly which comprises:

the light emitting module is connected with the first grounding end and is used for controlling whether to emit a light signal or not under the control of the sampling amplification voltage; and

a light receiving module connected to a second ground terminal, configured to output the first detection signal or the second detection signal based on whether the optical signal is received; the first ground terminal and the second ground terminal are not grounded in common.

3. The DC motor stall detection module of claim 2,

under the condition that the sampling amplification voltage drives the light emitting module to be in a conducting state, the light emitting module emits the optical signal; the optical transmitting module does not transmit the optical signal when the optical transmitting module is not in a conducting state;

the light receiving module outputs the second detection signal when the light receiving module receives the light signal; and under the condition that the light receiving module does not receive the light signal, the light receiving module outputs the first detection signal.

4. The direct current motor stall detection module of claim 2 or 3, wherein the module further comprises: and the motor control part is connected with the electrical isolation part and used for receiving the locked rotor detection signal and controlling whether the alternating current power supply loop supplies power to the direct current motor or not.

5. The DC motor stall detection module of claim 4, further comprising: a power supply part for supplying a first power supply and a second power supply; the output end of the first power supply comprises a first power supply end and the first grounding end; the first power supply is used for supplying power to the amplifying part and the light emitting module; the output end of the second power supply comprises a second power supply end and a second grounding end; the second power supply is used for supplying power to the light receiving module and the motor control part.

6. The DC motor stall detection module of claim 5,

the sampling part comprises a sampling resistor connected in series on the alternating current power supply loop;

the photoelectric isolation assembly comprises a threshold diode, a bypass resistor, a photoelectric coupler and a pull-up resistor; the photoelectric coupler is provided with a light emitting diode and a photosensitive triode; the bypass resistor is connected with the light emitting diode in parallel; the cathode of the threshold diode is connected with the amplifying part, the anode of the threshold diode is connected with the anode of the light emitting diode, and the cathode of the light emitting diode is connected with the first grounding end; the collector of the phototriode is connected with the second power end through the pull-up resistor, and the emitter of the phototriode is connected with the second grounding end;

the threshold diode, the bypass resistor and the light emitting diode constitute the light emitting module; the phototriode and the pull-up resistor form the light receiving module.

7. A motor drive apparatus, characterized in that the apparatus comprises:

the alternating current power supply loop is used for outputting alternating current;

the direct current power supply loop is used for receiving the alternating current and converting the alternating current into direct current to supply to the direct current motor;

the direct current motor stall detection module of claim 5 or 6; and

and the power supply control execution part is connected with the motor control part and the alternating current power supply loop and is used for controlling the on-off of the alternating current power supply loop according to the power supply control signal output by the motor control part.

8. The motor drive apparatus according to claim 7, wherein the motor control section controls the ac power supply circuit to be turned off via the power supply control execution section when the motor control section receives the second detection signal.

9. The motor drive device according to claim 7 or 8, wherein the power supply control executing portion includes:

a first switch control module for controlling a switch state of a first controllable switch based on the received power supply control signal; and

the first controllable switch is connected with the first switch control module and used for switching the on-off state of the first controllable switch to control the on-off state of the alternating current power supply loop; when the first controllable switch is in an on state, the alternating current power supply loop is switched on; when the first controllable switch is in an off state, the alternating current power supply loop is disconnected.

10. The motor drive apparatus according to claim 9,

the alternating current power supply loop comprises a first alternating current power supply branch connected with the first alternating current input end and a second alternating current power supply branch connected with the second alternating current input end;

the first controllable switch comprises a first relay; the first relay is provided with a first coil, a first fixed contact and a first movable contact which are arranged on the first alternating current power supply branch or the second alternating current power supply branch;

one end of the first coil is connected with the second power supply end, and the other end of the first coil is connected with the first switch control module; the first fixed contact is connected with the first alternating current input end or the second alternating current input end, and the first movable contact is connected with the second grounding end through the sampling part.

11. The motor drive apparatus according to claim 7,

the module further comprises: and the forward and reverse rotation control execution part is connected with the motor control part and the direct current power supply loop and is used for controlling the polarity of the voltage at two ends of the direct current motor according to the forward and reverse rotation control signal output by the motor control part.

12. The motor drive device according to claim 11, wherein the forward/reverse rotation control executing section includes:

the second switch control module is used for controlling the working state of a second controllable switch based on the received forward and reverse rotation control signal; and

and the second controllable switch is connected with the second switch control module and is controlled by the forward and reverse rotation control signal to adjust the connection between the direct current power supply loop and the direct current motor so as to convert the voltage polarity at the two ends of the direct current motor into positive polarity or negative polarity.

13. The motor drive apparatus according to claim 12,

the direct current power supply loop comprises a rectifying component, a first direct current power supply branch and a second direct current power supply branch; the input end of the rectifying component is connected with the alternating current power supply loop, and the output end of the rectifying component is connected with the direct current motor through the first direct current power supply branch and the second direct current power supply branch;

the second controllable switch comprises a second relay; the second relay is provided with a second coil, a second movable contact, a third movable contact, a second fixed contact, a third fixed contact, a fourth fixed contact and a fifth fixed contact;

one end of the second coil is connected with the second switch control module, and the other end of the second coil is connected with the second power supply end; the second movable contact, the second fixed contact and the fifth fixed contact are all arranged on the first direct current supply branch circuit; the third movable contact, the third fixed contact and the fourth fixed contact are all arranged on the second direct current supply branch circuit; the second movable contact is capable of being in contact with the second stationary contact or the third stationary contact, and the third movable contact is capable of being in contact with the fourth stationary contact or the fifth stationary contact.

14. A method for detecting locked rotor of a direct current motor is characterized by comprising the following steps:

sampling the motor power supply current flowing through the alternating current power supply loop of the direct current motor, and converting the sampled voltage into sampled voltage;

if the power supply current of the motor does not exceed the preset current, providing a first detection signal; if the motor power supply current exceeds the preset current, providing a second detection signal; the first detection signal and the second detection signal both belong to locked rotor detection signals, and the locked rotor detection signals are electrically isolated from the sampling voltage.

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