Motor drive circuits and electrical equipment

Abstract

The present invention discloses a motor drive circuit and electrical equipment, wherein the motor drive circuit includes: a motor, a switching module and a first switch; the first end of the motor is connected to one end of the first switch and a first power source respectively through the switching module, and the second end of the motor is connected to one end of the first switch and the first power source respectively through the switching module; the switching module is used to control the switching of the motor forward and reverse according to the motor forward and reverse control signal; the first switch is used to control the on and off of the motor forward circuit or reverse circuit. In the above motor drive circuit, the connection of the motor forward circuit or reverse circuit is realized through the switching module, and then the on and off of the forward circuit or reverse circuit is realized through the first switch, thereby realizing the forward and reverse rotation of the motor. The motor drive circuit is simple, which solves the problem of complex push rod motor control circuit in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of electrical equipment technology, and in particular to a motor drive circuit and electrical equipment. Background Art

[0002] The range hood usually realizes the automatic opening and closing of the range hood smoke guide plate by the forward and reverse rotation of the push rod motor. Chinese patent document CN204406073U discloses a control circuit of an electric push rod of the range hood, including a DC power supply, a DC brush motor, a current detection unit and a switch control unit. The DC brush motor drives the motor push rod to move, and also includes a plurality of relays. The switch control unit receives an external input control signal and controls the plurality of relays to connect the DC power supply to the DC brush motor in a positive or reverse manner so that the DC brush motor rotates forward or reversely. The current detection unit detects the current size of the DC brush motor and inputs the obtained current signal to the switch control unit for processing. The switch control unit outputs a control signal according to the size of the current signal to control the movement of the plurality of relays, thereby controlling the operation of the DC brush motor.

[0003] The above-mentioned several relays are three relays, and a three-relay combination controller is used to make the push rod motor rotate forward and reverse. Too many relays make the circuit connection method more complicated. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a motor drive circuit and an electrical device to solve the problem of complex push rod motor control circuits in the prior art.

[0005] An embodiment of the present invention provides a motor drive circuit, comprising: a motor, a switching module and a first switch; wherein the first end of the motor is connected to one end of the first switch and a first power supply respectively through the switching module, and the second end of the motor is connected to the one end of the first switch and the first power supply respectively through the switching module; the switching module is used to control the switching of forward and reverse rotation of the motor according to a motor forward and reverse rotation control signal; the first switch is used to control the on and off of the forward rotation circuit or the reverse rotation circuit of the motor.

[0006] Optionally, the switching module includes a first relay, a first drive unit, a second relay and a second drive unit; wherein, the first end of the coil of the first relay is connected to the second power supply, the second end of the coil of the first relay is connected to the first drive unit, the moving contact of the first relay is connected to the first end of the motor, the normally open contact of the first relay is connected to the first power supply, and the normally closed contact of the first relay is connected to the first switch; the first end of the coil of the second relay is connected to the third power supply, the second end of the coil of the second relay is connected to the second drive unit, the moving contact of the second relay is connected to the second end of the motor, the normally open contact of the second relay is connected to the first power supply, and the normally closed contact of the second relay is connected to the first switch.

[0007] Optionally, the switching module includes a third relay and a third drive unit, wherein the first end of the coil of the third relay is connected to the fourth power supply, and the second end of the coil of the third relay is connected to the third drive unit; the first moving contact of the third relay is connected to the first end of the motor, and the second moving contact of the third relay is connected to the second end of the motor; the first normally open contact and the second normally closed contact of the third relay are connected to the fourth power supply or the first switch, and the first normally closed contact and the second normally open contact are connected to the first switch or the fourth power supply.

[0008] Optionally, the first driving unit includes a first transistor, a second transistor, a first diode, a second diode and a first energy storage capacitor; wherein the first end of the first diode is connected to the forward and reverse rotation control signal of the first motor, and the second end of the first diode is respectively connected to the first end of the first energy storage capacitor, the first end of the second diode and the control end of the first transistor; the second end of the second diode is connected to the control end of the second transistor; the first end of the second transistor is connected to the second end of the coil of the first relay, and the second end of the second transistor is connected to the first end of the first transistor; the second end of the first transistor and the second end of the first energy storage capacitor are both connected to the ground wire;

[0009] and / or,

[0010] The second driving unit includes a third triode, a fourth triode, a third diode, a fourth diode and a second energy storage capacitor; wherein the first end of the third diode is connected to the forward and reverse rotation control signal of the second motor, and the second end of the third diode is respectively connected to the first end of the second energy storage capacitor, the first end of the fourth diode and the control end of the third triode; the second end of the fourth diode is connected to the control end of the fourth triode; the first end of the fourth triode is connected to the second end of the coil of the second relay, and the second end of the fourth triode is connected to the first end of the third triode; the second end of the third triode and the second end of the second energy storage capacitor are both connected to the ground wire;

[0011] and / or,

[0012] The third driving unit includes a fifth transistor, a sixth transistor, a fifth diode, a sixth diode and a third energy storage capacitor; wherein, the first end of the fifth diode is connected to the forward and reverse rotation control signal of the third motor, and the second end of the fifth diode is respectively connected to the first end of the third energy storage capacitor, the first end of the sixth diode and the control end of the fifth transistor; the second end of the sixth diode is connected to the control end of the sixth transistor; the first end of the sixth transistor is connected to the second end of the coil of the third relay, and the second end of the sixth transistor is connected to the first end of the fifth transistor; the second end of the fifth transistor and the second end of the third energy storage capacitor are both connected to the ground wire.

[0013] Optionally, it also includes: a current limiting resistor;

[0014] The current limiting resistor is connected in series to the control end of the first transistor and / or the control end of the second transistor;

[0015] and / or,

[0016] The current limiting resistor is connected in series to the control end of the third transistor and / or the control end of the fourth transistor;

[0017] and / or,

[0018] The current limiting resistor is connected in series to the control end of the fifth transistor and / or the control end of the sixth transistor.

[0019] Optionally, it also includes: a resistor to prevent mis-turn-on;

[0020] The mis-turn-on prevention resistor is connected between the control terminal of the first transistor and the second terminal of the first transistor;

[0021] and / or,

[0022] The mis-turn-on prevention resistor is connected between the control terminal of the third transistor and the second terminal of the third transistor;

[0023] and / or,

[0024] The mis-turn-on prevention resistor is connected between the control end of the fifth transistor and the second end of the fifth transistor.

[0025] Optionally, it also includes: a discharge resistor;

[0026] The discharge resistor is connected in parallel with the first energy storage capacitor;

[0027] and / or,

[0028] The discharge resistor is connected in parallel with the second energy storage capacitor;

[0029] and / or,

[0030] The discharge resistor is connected in parallel with the third energy storage capacitor.

[0031] Optionally, a protection capacitor and a protection diode are also included;

[0032] The protection capacitor is connected in series between the first motor forward and reverse control signal and the first diode, the second end of the protection diode is connected to the first end of the first diode, and the first end of the protection diode is connected to the ground wire;

[0033] and / or,

[0034] The protection capacitor is connected in series between the second motor forward and reverse control signal and the third diode, the second end of the protection diode is connected to the first end of the third diode, and the first end of the protection diode is connected to the ground wire;

[0035] and / or,

[0036] The protection capacitor is connected in series between the third motor forward and reverse control signal and the fifth diode, the second end of the protection diode is connected to the first end of the fifth diode, and the first end of the protection diode is connected to the ground wire.

[0037] Optionally, it also includes: a motor filter circuit connected in parallel with the motor.

[0038] Optionally, the method further includes: a detection unit connected to the first switch and configured to detect the current of the motor.

[0039] Optionally, the first switch includes a switching transistor, a first end of the switching transistor is connected to the switching module, a second end of the switching transistor is connected to the detection unit, a control end of the switching transistor is connected to a switching signal, and the switching signal includes a PWM signal.

[0040] An embodiment of the present invention further provides an electrical device, comprising any motor drive circuit as described above.

[0041] Optionally, the electrical appliance includes a range hood.

[0042] The technical solution of the present invention has the following advantages:

[0043] The motor drive circuit provided by the present invention includes: a motor, a switching module and a first switch; wherein the first end of the motor is respectively connected to one end of the first switch and a first power source through the switching module, and the second end of the motor is respectively connected to the one end of the first switch and the first power source through the switching module; the switching module is used to control the switching of the forward and reverse rotation of the motor according to the motor forward and reverse rotation control signal; the first switch is used to control the on and off of the forward or reverse rotation circuit of the motor. In the above motor drive circuit, the connection of the forward or reverse rotation circuit of the motor is realized through the switching module, and then the on and off of the forward or reverse rotation circuit is realized through the first switch, thereby realizing the forward and reverse rotation of the motor. The motor drive circuit is simple, which solves the problem of complex push rod motor control circuit in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a circuit diagram of a specific example of a motor drive circuit in an embodiment of the present invention;

[0046] Figure 2 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0047] Figure 3 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0048] Figure 4 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0049] Figure 5 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0050] Figure 6 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0051] Figure 7 is a circuit diagram of another specific example of a motor driving circuit in an embodiment of the present invention;

[0052] Figure 8 FIG. 4 is a circuit diagram of another specific example of the motor driving circuit in an embodiment of the present invention.

[0053] Reference numerals:

[0054] M, motor; 2, switching module; 21, first drive unit; 22, second drive unit; 3, first switch; 4, detection unit; V1, first power supply; V2, second power supply; V3, third power supply; V4, fourth power supply; K1, first relay; K2, second relay; K3, third relay; Q2, switch transistor; Q5, first transistor; Q4, second transistor; Q3, third transistor; Q1, fourth transistor; Q6, fifth transistor; Q7, sixth transistor; D1, first diode; D2, second diode; D6, third diode; D7, fourth diode; D9, fifth diode; D10, sixth diode; D3, first protection diode; D8, second protection diode; D11, third protection diode; D4, first relay protection diode; D5, second relay protection diode; EC1, first energy storage capacitor; EC2, second energy storage capacitor; EC3, third energy storage capacitor; R3, first current limiting resistor; R1, second current limiting resistor; R10, the third current limiting resistor; R8, the fourth current limiting resistor; R7, the seventh current limiting resistor; R4, the first anti-misleading turn-on resistor; R9, the second anti-misleading turn-on resistor; R2, the first discharge resistor; R11, the second discharge resistor; R5, the filter resistor; R6, the detection resistor; R12, the fifth current limiting resistor; R13, the sixth current limiting resistor; R14, the third anti-misleading turn-on resistor; R15, the third discharge resistor; C1, the first protection capacitor; C3, the second protection capacitor; C2, the filter capacitor; C4, the third protection capacitor; S1, the switch control signal; S2, the first motor forward and reverse control signal; S3, the second motor forward and reverse control signal; S4, the detection signal; S5, the third motor forward and reverse control signal. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. It should also be noted that the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0057] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] This embodiment provides a motor drive circuit, which is applied to a motor (such as a push rod motor) to realize the forward and reverse rotation of the motor, thereby solving the problem of complex motor control circuits in the prior art. Figure 1 As shown, the motor drive circuit includes: a motor M, a switching module 2 and a first switch 3. The first end of the motor M is connected to one end of the first switch 3 and the first power supply through the switching module 2, and the second end of the motor M is connected to one end of the first switch 3 and the first power supply through the switching module 2; the switching module 2 is used to control the switching of the forward and reverse rotation of the motor M according to the motor forward and reverse rotation control signal; the first switch 3 is used to control the on and off of the forward rotation circuit or the reverse rotation circuit of the motor M.

[0059] In the above-mentioned motor drive circuit, the connection of the forward circuit or the reverse circuit of the motor is realized through the switching module, and then the forward circuit or the reverse circuit is turned on and off through the first switch, thereby realizing the forward and reverse rotation of the motor. The motor drive circuit is simple, which solves the problem of complex push rod motor control circuit in the prior art.

[0060] In an optional embodiment, specifically: when the motor M is rotating forward, the first end of the motor M is connected to the first power supply V1 through the switching module, and the second end of the motor M is connected to one end of the first switch through the switching module, completing the connection of the motor forward rotation circuit. At this time, turning on the first switch realizes the forward rotation of the motor; when the motor M is reversing, the first end of the motor M is connected to one end of the first switch through the switching module, and the second end of the motor M is connected to the first power supply V1 through the switching module, completing the connection of the motor reversal circuit. At this time, turning on the first switch realizes the reversal of the motor. Of course, in other embodiments, when the first end of the motor M is connected to the first power supply and the second end is connected to the first switch, it can also be a motor reversal circuit; when the first end is connected to one end of the first switch and the second end is connected to the first power supply, it is a motor forward rotation circuit. The specific connection method and the corresponding relationship between the forward and reverse rotation of the motor can be reasonably set according to needs, and this embodiment does not limit this.

[0061] In an optional embodiment, the motor may be a push rod motor, which is usually used in household appliances, such as range hoods. The forward and reverse rotation of the push rod motor automatically opens and closes the smoke guide plate of the range hood, thereby adjusting the smoke guide plate of the range hood. Of course, in other embodiments, the motor may also be other motors in the prior art that can achieve forward and reverse rotation. It should be noted that the application field of the motor is not limited to household appliances, but can also be applied to other fields that achieve control through forward and reverse rotation of the motor, which is not limited in this embodiment. It should also be noted that the motor drive circuit in this embodiment is not limited to push rod motors, but can also be extended to other DC motors.

[0062] In an alternative embodiment, if Figure 2 As shown, the first switch 3 can be a switch transistor Q2. Specifically, the switch transistor Q2 can be an NPN transistor. The collector of the switch transistor Q2 is connected to the switching module, the emitter is connected to the ground wire GND, and the base is connected to the switch control signal S1. The switching of the motor forward circuit or reverse circuit is controlled according to the switch control signal. The switching speed of the transistor is fast and the production cost is low. Of course, in other embodiments, the first switch can also be a PNP transistor, or a switching device such as a MOS tube or a relay with a higher production cost, which can be reasonably set according to needs.

[0063] In an optional embodiment, the switch control signal can be a PWM signal, so that the motor can be PWM-controlled during forward or reverse rotation, and the control method is simple, convenient, and easy to operate. Of course, in other embodiments, the switch control signal can also be a high potential, which can be reasonably set according to needs.

[0064] In an alternative embodiment, if Figure 2As shown, the switching module 2 includes a first relay K1, a first drive unit 21, a second relay K2 and a second drive unit 22. The first end of the coil of the first relay K1 is connected to the second power supply V2, the second end of the coil of the first relay K1 is connected to the first drive unit 21, the moving contact of the first relay K1 is connected to the first end A of the motor M, the normally open contact of the first relay K1 is connected to the first power supply V1, and the normally closed contact of the first relay K1 is connected to the first switch 3; the first end of the coil of the second relay K2 is connected to the third power supply V3, the second end of the coil of the second relay K2 is connected to the second drive unit 22, the moving contact of the second relay 24 is connected to the second end B of the motor M, the normally open contact of the second relay K2 is connected to the first power supply V1, and the normally closed contact of the second relay K2 is connected to the first switch 3. In this embodiment, as Figure 3 As shown, the second power supply V2 and the third power supply V3 share a power supply VCC, which can simplify the circuit and reduce the production cost; of course, in other embodiments, the second power supply and the third power supply can also be connected to two power supplies respectively, and can be reasonably set according to needs.

[0065] In an optional embodiment, the first power supply V1, the second power supply V2 and the third power supply V3 can share a power supply, and the voltage value can be 24V or 12V; of course, different power supplies can be connected separately as needed, and the voltage values ​​can be set to be the same or different. The voltage values ​​can be set reasonably as needed.

[0066] The first switch in the above switching module is connected to the ground wire, the normally closed contact is connected to the first switch, and the normally open contact is connected to the power supply. This arrangement improves the safety and reliability of the entire circuit. Of course, in other embodiments, the normally open contact can be connected to the first switch, and the normally closed contact can be connected to the power supply. This arrangement can also achieve the same function, and can be reasonably set according to needs.

[0067] The switching module in the above motor drive circuit can realize the connection of the forward loop or the reverse loop through only two relays, and the circuit structure is simple; only one relay is required to operate during forward or reverse rotation, and the control method is simple, saving electricity and reducing production costs.

[0068] In an alternative embodiment, if Figure 3As shown, the first driving unit 21 includes a first transistor Q5, a second transistor Q4, a first diode D1, a second diode D2 and a first energy storage capacitor EC1. Among them, the first end of the first diode D1 is connected to the first motor forward and reverse control signal S2, and the second end of the first diode D1 is respectively connected to the first end of the first energy storage capacitor EC1, the first end of the second diode D2 and the control end of the first transistor Q5; the second end of the second diode D2 is connected to the control end of the second transistor Q4; the first end of the second transistor Q4 is connected to the second end of the coil of the first relay K1, and the second end of the second transistor Q4 is connected to the first end of the first transistor Q5; the second end of the first transistor Q5 and the second end of the first energy storage capacitor EC1 are both connected to the ground wire GND. When the first motor forward and reverse control signal S2 outputs a high level, the first transistor Q5 is turned on first, and then the second transistor Q4 is turned on due to the second diode D2. After the two transistors (Q5 and Q4) are turned on at the same time, the coil of the first relay K1 is energized, and the first relay K1 is activated. The moving contact of the first relay K1 is connected to the normally open contact, thereby connecting to the first power supply V1; the second relay does not operate, and its moving contact is still connected to the normally closed contact, completing the connection of the motor forward rotation circuit; then, the motor can be rotated forward under the control of the first switch.

[0069] like Figure 3 As shown, the second driving unit 22 includes a third transistor Q3, a fourth transistor Q1, a third diode D6, a fourth diode D7 and a second energy storage capacitor EC2. Among them, the first end of the third diode D6 is connected to the second motor forward and reverse control signal S3, and the second end of the third diode D6 is respectively connected to the first end of the second energy storage capacitor EC2, the first end of the fourth diode D7 and the control end of the third transistor Q3; the second end of the fourth diode D7 is connected to the control end of the fourth transistor Q1; the first end of the fourth transistor Q1 is connected to the second end of the coil of the second relay K2, and the second end of the fourth transistor Q1 is connected to the first end of the third transistor Q3; the second end of the third transistor Q3 and the second end of the second energy storage capacitor EC2 are both connected to the ground wire GND. When the second motor forward and reverse control signal S3 outputs a high level, the third transistor Q3 is turned on first, and then the fourth transistor Q1 is turned on later due to the fourth diode D7. After the two transistors (Q3 and Q1) are turned on at the same time, the coil of the second relay K2 is energized, and the second relay is activated. The moving contact of the second relay is connected to the normally open contact, thereby connecting to the first power supply V1; the first relay K1 does not operate, and its moving contact is still connected to the normally closed contact, completing the connection of the motor reversal circuit; then, the motor can be reversed under the control of the first switch.

[0070] Specifically, the first energy storage capacitor EC1 and the second energy storage capacitor EC2 are both electrolytic capacitors, which have a large capacitance and a low cost. Of course, in other embodiments, other capacitors in the prior art, such as tantalum capacitors, etc., can also be used and can be reasonably set according to needs.

[0071] In the above-mentioned first drive circuit and second drive circuit, two transistors are connected in series to control a relay. In the event that any one component is damaged, the motor will not malfunction, and the safety factor is high. In addition, the two groups of transistors connected in series drive two relays in parallel respectively, and control the two power lines of the motor at the same time. Even if one of the relays is damaged, it can be ensured that the motor will not be powered on, and the safety factor is extremely high.

[0072] It should be noted that the first transistor Q5, the second transistor Q4, the third transistor Q3 and the fourth transistor Q1 are all NPN transistors; of course, in other embodiments, the transistors may also be PNP type, which can also achieve the technical effects of the present invention, and can be reasonably set according to needs.

[0073] In an alternative embodiment, the motor drive circuit further includes: a current limiting resistor; the current limiting resistor is connected in series to the control end of the first transistor Q5 and / or the control end of the second transistor Q4. And / or, the current limiting resistor is connected in series to the control end of the third transistor Q3 and / or the control end of the fourth transistor Q1. The series resistor is connected in series to the control end (base) of the transistor to protect the transistor.

[0074] Specifically, Figure 4 As shown, the current limiting resistor is connected in series to the control end of the first triode Q5, and the current limiting resistor here is represented as the first current limiting resistor R3; the current limiting resistor is connected in series to the control end of the second triode Q4, and the current limiting resistor here is represented as the second current limiting resistor R1; the current limiting resistor is connected in series to the control end of the third triode Q3, and the current limiting resistor here is represented as the third current limiting resistor R10; the current limiting resistor is connected in series to the control end of the fourth triode Q1, and the current limiting resistor here is represented as the fourth current limiting resistor R8. Of course, in other embodiments, the current limiting resistor can also be set only at the control end of the first triode Q5 and the control end of the third triode Q3, and it can be reasonably set according to needs.

[0075] In another alternative embodiment, Figure 4 As shown, the first switch is a switch transistor Q2, and the motor drive circuit further includes a current limiting resistor arranged on the control end of the first switch. Specifically, the current limiting resistor here is represented as a seventh current limiting resistor R7, and the seventh current limiting resistor R7 is connected in series between the control end of the switch transistor Q2 and the switch control signal S1.

[0076] It should be noted that the resistance value of the current limiting resistor can be set to the same or different resistance values ​​at different setting positions according to actual needs. It should also be noted that the position of the current limiting resistor is not limited to the position described in the drawings of this embodiment, and the technical solutions of directly connecting the current limiting resistor in series with the control end of the transistor or indirectly connecting in series through other components all fall within the protection scope of the present invention.

[0077] In another alternative embodiment, the motor drive circuit further includes: a mis-turn-on prevention resistor; the mis-turn-on prevention resistor is connected between the control end of the first transistor Q5 and the second end of the first transistor Q5; and / or, the mis-turn-on prevention resistor is connected between the control end of the third transistor Q3 and the second end of the third transistor Q3. The mis-turn-on prevention resistor is arranged between the control end and the second end of the transistor, and the mis-turn-on of the transistor due to interference, etc., improves the reliability of the motor drive circuit.

[0078] Specifically, Figure 4 As shown, the misleading turn-on resistor is connected between the control end of the first transistor Q5 and the second end of the first transistor Q5, and the misleading turn-on resistor is represented as the first misleading turn-on resistor R4; the misleading turn-on resistor is connected between the control end of the third transistor Q3 and the second end of the third transistor Q3, and the misleading turn-on resistor is represented as the second misleading turn-on resistor R9. Of course, in other embodiments, the misleading turn-on resistor can also be set only at the first transistor Q5 or only at the third transistor Q3, and it can be reasonably set according to needs.

[0079] In another alternative embodiment, the motor drive circuit further includes: a discharge resistor; the discharge resistor is connected in parallel with the first energy storage capacitor EC1; and / or the discharge resistor is connected in parallel with the second energy storage capacitor EC2. The discharge resistor is connected to the energy storage capacitor to provide a discharge circuit for the energy storage capacitor and reduce the discharge time.

[0080] Specifically, Figure 4 As shown, the discharge resistor is connected in parallel with the first energy storage capacitor EC1, and the discharge resistor is represented as the first discharge resistor R2; the discharge resistor is also connected in parallel with the second energy storage capacitor EC2, and the discharge resistor is represented as the second discharge resistor R11. Of course, in other embodiments, the discharge resistor can also be connected in parallel only with the first energy storage capacitor EC1 or only with the second energy storage capacitor EC2, and it can be reasonably set according to needs.

[0081] In another alternative embodiment, in order to further improve the safety and reliability of the motor drive circuit, the motor forward and reverse control signal is driven by a square wave signal. At this time, the motor drive circuit also includes: a protection capacitor and a protection diode; the protection capacitor is connected in series between the first motor forward and reverse control signal S2 and the first diode D1, the second end of the protection diode is connected to the first end of the first diode D1, and the first end of the protection diode is connected to the ground wire; and / or, the protection capacitor is connected in series between the second motor forward and reverse control signal S3 and the third diode D6, the second end of the protection diode is connected to the first end of the third diode D6, and the first end of the protection diode is connected to the ground wire. The first motor forward and reverse control signal S2 and the second motor forward and reverse control signal S3 can be provided by the control chip, in order to protect the capacitor and the protection diode from causing damage to components such as transistors or relays when the control chip is damaged. Specifically, when the control chip is damaged, a high potential or a low potential is usually output. Due to the isolation effect of the protection capacitor, no matter whether the motor forward and reverse signal output by the control chip is a high potential or a low potential, the motor forward and reverse signal cannot reach the transistor control end, thereby playing a protective role.

[0082] Specifically, Figure 4 As shown, when the protection capacitor and the protection diode are arranged on the first motor forward and reverse control signal side, the protection capacitor is represented as the first protection capacitor C1, and the protection diode is represented as the first protection diode D3. The first protection capacitor C1 is connected in series between the first motor forward and reverse control signal S2 and the first diode D1, the second end (cathode) of the first protection diode D3 is connected to the first end (anode) of the first diode D1, and the first end (anode) of the first protection diode D3 is connected to the ground wire GND.

[0083] like Figure 4 As shown, when the protection capacitor and the protection diode are arranged on the second motor forward and reverse control signal side, the protection capacitor is represented as the second protection capacitor C3, and the protection diode is represented as the second protection diode D8. The second protection capacitor C3 is connected in series between the second motor forward and reverse control signal S3 and the third diode D6, the second end (cathode) of the second protection diode D8 is connected to the first end (anode) of the third diode D6, and the first end (anode) of the second protection diode D8 is connected to the ground wire GND.

[0084] In another alternative embodiment, Figure 4 As shown, the motor drive circuit further includes: a first relay protection diode D4 connected in parallel with the first relay coil for protecting the first relay coil. Specifically, the cathode of the first relay protection diode D4 is connected to the first end of the first relay coil, and the anode is connected to the second end of the first relay coil.

[0085] In another alternative embodiment, Figure 4 As shown, the motor drive circuit also includes: a second relay protection diode D5, connected in parallel with the second relay coil, for protecting the second relay coil. Specifically, the cathode of the second relay protection diode D5 is connected to the first end of the second relay K2 coil, and the anode is connected to the second end of the second relay K2 coil.

[0086] In another alternative embodiment, Figure 4 As shown, the motor drive circuit also includes: a motor filter module, which is connected in parallel with the motor, specifically including a filter resistor R5 and a filter capacitor C2 connected in series, which is used to filter out related interference when the motor is commutating and rotating to prevent the motor from sparking and causing damage to the motor.

[0087] In another alternative embodiment, Figure 5 As shown, the motor driving circuit further includes: a detection unit 4 connected to the first switch 3, for detecting the current of the motor M. Specifically, as Figure 6 As shown, the detection unit may be a detection resistor R6, which detects the current of the motor and converts the detected current into a voltage, and connects the voltage to the detection signal S4 of the controller to facilitate subsequent processing by the controller; of course, in other embodiments, it may also be other detection devices in the prior art, which can be reasonably set according to needs.

[0088] In another alternative embodiment, the motor drive circuit further includes: a controller connected to the motor drive circuit, and used to control the motor according to the current of the motor. Specifically, the controller can be a control chip, and the switch control signal S1 and the motor forward and reverse control signal (S2 and S3) can share the same control chip, which can reduce production costs. Of course, in other embodiments, each signal can also be connected to multiple control chips respectively, and can be reasonably set according to needs.

[0089] The controller controls the motor according to the detected current, and the above control may include controlling the motor to stop rotating after the motor is stalled or the smoke guide plate in the range hood is moved into position. For example, when the motor is stalled, the motor current will increase significantly, and the voltage detected on the detection resistor R6 will also increase. The controller disconnects the motor circuit according to the voltage to stop the motor. For another example, the smoke guide plate position detection device in the range hood sends the position signal of the smoke guide plate to the controller. When the smoke guide plate moves to a suitable position, the controller controls the motor to stop rotating so that the smoke guide plate stops at that position.

[0090] Specifically, the controller can disconnect the entire circuit by controlling the travel switch inside the push rod motor, thereby stopping the motor from rotating; the circuit can also be disconnected and the motor can be stopped by a motor forward and reverse control signal or a switch control signal; the specific control method can be reasonably set according to actual needs, and this embodiment does not limit this.

[0091] like Figure 7 is a circuit diagram of a specific example of the motor drive circuit in this embodiment, Figure 7 Take the working principle of the motor drive circuit as an example to introduce in detail. Figure 7 The M in the figure indicates the push rod motor, and the voltage value of the power supply VCC can be 24V or 12V. The normally closed point of the first relay K1 is M-, and the normally closed point of the second relay K2 is M-; when the A terminal of the push rod motor is connected to M+ and the B terminal is connected to M-, the push rod motor rotates forward; when the A terminal of the push rod motor is connected to M- and the B terminal is connected to M+, the push rod motor rotates reversely.

[0092] When the push rod motor rotates forward, the second relay K2 does not work, and the B terminal of the motor is connected to the normally closed point M- of the second relay K2. The relay drives the square wave through C1 and diodes D1, D2, and EC1 to output a fixed voltage after rectification and filtering. This voltage drives transistors Q4 and Q5 at the same time. After transistors Q4 and Q5 are turned on, the first relay K1 is connected from the normally closed point to M+. The driver I / O port gives a high level to turn on transistor Q2, so that M- is connected to GND. At this time, the A terminal of the motor is M+, the B terminal is M-, and the motor rotates forward.

[0093] When the push rod motor reverses, the first relay K1 does not work, and the A terminal of the motor is connected to the normally closed point M- of the first relay K1. The relay drives the square wave through C3 and diodes D6, D7, and EC2 to rectify and filter, and then output a fixed voltage. This voltage drives transistors Q1 and Q3 at the same time. After transistors Q1 and Q3 are turned on, the second relay K2 is connected from the normally closed point to M+. The driver I / O port gives a high level to turn on transistor Q2, so that M- is connected to GND. At this time, the A terminal of the motor is M-, the B terminal is M+, and the motor reverses.

[0094] In the case of damaged components of the motor drive circuit in the prior art, the voltage at both ends of the push rod motor is not controlled, and the rotation of the push rod motor is not controlled, so that the smoke guide plate may have the risk of injuring people. At the same time, the motor may be in a stalled state, causing damage to the motor, and even causing the mainboard that supplies power to the motor to overload. In the above-mentioned motor drive circuit in this embodiment, a chip I / O port controller has two transistors in series to drive the relay. In the case of damage to one transistor and the chip I / O port, the motor will not be powered on; the two transistors in series drive two relays in parallel, and control the two power lines of the motor at the same time, which is extremely safe. Even if one relay is damaged, it is guaranteed that the motor will not be powered on; if any two components are damaged, the relay cannot be attracted, and the load will not malfunction; two transistors are connected in series to control the relay. In the case of damage to any two components, the motor will not malfunction, with a high safety factor, and is suitable for the range hood push rod motor drive circuit, with a high safety factor.

[0095] It should be noted that the technical solution of controlling a relay by three or more transistors connected in series also belongs to the concept of the present invention, and these technical solutions all fall within the protection scope defined by the present invention.

[0096] In another alternative embodiment, the switching module 2 includes a third relay K3 and a third drive unit; wherein, the first end of the coil of the third relay K3 is connected to the fourth power supply V4, and the second end of the coil of the third relay K3 is connected to the third drive unit; the first moving contact of the third relay K3 is connected to the first end of the motor M, and the second moving contact of the third relay K3 is connected to the second end of the motor M; the first normally open contact and the second normally closed contact of the third relay K3 are connected to the fourth power supply or the first switch, and the first normally closed contact and the second normally open contact are connected to the first switch or the fourth power supply.

[0097] Specifically, Figure 8 As shown, the first normally open contact and the second normally closed contact of the third relay are connected to the fourth power supply, and the first normally closed contact and the second normally open contact are connected to the first switch. Such connection makes it possible that when the third relay coil is not powered, the first normally closed contact is connected to the first switch, the second normally closed contact is connected to the fourth power supply, and the motor reversal circuit is connected. When the first switch is turned on, the motor is reversed. On the contrary, when the third relay coil is powered, the first normally open contact is connected to the fourth power supply, the second normally open contact is connected to the first switch, and the motor forward circuit is connected. When the first switch is turned on, the motor is forwarded. Of course, in other embodiments, the first normally open contact and the second normally closed contact of the third relay can also be connected to the first switch, and the first normally closed contact and the second normally open contact are connected to the fourth power supply. At this time, when the third relay coil is not powered, the motor forward circuit is connected, and when the coil is powered, the motor reverse circuit is connected. Such a setting can also achieve the same function, and the specific connection method can be reasonably set according to needs. The switching module realizes the switching of the motor forward and reverse circuits only through the linkage of two sets of switches of a double-pole double-throw relay. The double-pole double-throw relay is used instead of two single-pole double-throw relays, which saves installation space and reduces production costs.

[0098] like Figure 8As shown, the third driving unit includes a fifth transistor Q6, a sixth transistor Q7, a fifth diode D9, a sixth diode D10 and a third energy storage capacitor EC3; wherein, the first end of the fifth diode D9 is connected to the third motor forward and reverse control signal S5, and the second end of the fifth diode D9 is respectively connected to the first end of the third energy storage capacitor EC3, the first end of the sixth diode D10 and the control end of the fifth transistor Q6; the second end of the sixth diode D10 is connected to the control end of the sixth transistor Q7; the first end of the sixth transistor Q7 is connected to the second end of the coil of the third relay K3, and the second end of the sixth transistor Q7 is connected to the first end of the fifth transistor Q6; the second end of the fifth transistor Q6 and the second end of the third energy storage capacitor EC3 are both connected to the ground wire GND.

[0099] like Figure 8 As shown, the motor drive circuit also includes: a current limiting resistor connected in series to the control end of the fifth transistor Q6, and the current limiting resistor here is represented as the fifth current limiting resistor R12; a current limiting resistor connected in series to the control end of the sixth transistor Q7, and the current limiting resistor here is represented as the sixth current limiting resistor R13.

[0100] like Figure 8 As shown, the motor driving circuit further includes: a mis-turn-on prevention resistor connected between the control end of the fifth transistor Q6 and the second end of the fifth transistor Q6 , wherein the mis-turn-on prevention resistor is represented as a third mis-turn-on prevention resistor R14 .

[0101] like Figure 8 As shown, the motor drive circuit further includes: a discharge resistor connected in parallel with the third energy storage capacitor EC3, where the discharge resistor is represented as a third discharge resistor R15.

[0102] like Figure 8 As shown, the motor driving circuit also includes: a third protection capacitor C4 connected in series between the third motor forward and reverse control signal S5 and the fifth diode D9; the second end of the third protection diode D11 is connected to the first end of the fifth diode D9, and the first end of the third protection diode D11 is connected to the ground line GND.

[0103] The above motor drive circuit can realize the control of the forward and reverse rotation of the motor through a double-pole double-throw relay. The two transistors can also increase the reliability and safety of the circuit. The circuit requires fewer components, saves installation space, and reduces production costs.

[0104] In an alternative embodiment, the first switch 3 in the above embodiment may also be two or more transistors connected in series. This arrangement further improves the reliability of the first switch, making the safety and reliability of the entire motor drive circuit higher. Figure 3-Figure 8 The series connection method of the transistors in will not be repeated here.

[0105] This embodiment also provides an electrical device, including a motor drive circuit as described in any of the above embodiments. In an optional embodiment, the electrical device includes a DC motor (e.g., a push rod motor) with forward and reverse rotation functions, and the electrical device can be a range hood, and the forward and reverse rotation of the push rod motor in the range hood is achieved through the above motor drive circuit. Of course, in other embodiments, the electrical device can also be other electrical appliances in the prior art that have a DC motor and the DC motor needs to be forward and reversed, and can be reasonably set according to needs.

[0106] Since the above-mentioned electrical equipment adopts the motor driving circuit in this embodiment, it also has the advantages of simple control circuit and high reliability.

[0107] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A motor drive circuit, characterized in that: include: A motor (M), a switching module (2) and a first switch (3); wherein, The first end of the motor (M) is respectively connected to one end of the first switch (3) and the first power source through the switching module (2), and the second end of the motor (M) is respectively connected to the one end of the first switch (3) and the first power source through the switching module (2); The switching module (2) is used to control the switching between forward and reverse rotation of the motor (M) according to the motor forward and reverse rotation control signal; The first switch (3) is used to control the on / off of the forward circuit or the reverse circuit of the motor (M); The switching module (2) comprises a first relay (K1), a first drive unit (21), a second relay (K2) and a second drive unit (22); wherein: The first end of the coil of the first relay (K1) is connected to the second power supply, the second end of the coil of the first relay (K1) is connected to the first drive unit (21), the moving contact of the first relay (K1) is connected to the first end of the motor (M), the normally open contact of the first relay (K1) is connected to the first power supply, and the normally closed contact of the first relay (K1) is connected to the first switch (3); The first end of the coil of the second relay (K2) is connected to a third power supply, the second end of the coil of the second relay (K2) is connected to a second drive unit (22), the moving contact of the second relay (K2) is connected to a second end of the motor (M), the normally open contact of the second relay (K2) is connected to the first power supply, and the normally closed contact of the second relay (K2) is connected to the first switch (3); Alternatively, the switching module (2) comprises a third relay (K3) and a third drive unit, wherein: A first end of the coil of the third relay (K3) is connected to a fourth power source, and a second end of the coil of the third relay (K3) is connected to a third drive unit; The first moving contact of the third relay (K3) is connected to the first end of the motor (M), and the second moving contact of the third relay (K3) is connected to the second end of the motor (M); The first normally open contact and the second normally closed contact of the third relay (K3) are connected to the fourth power supply or the first switch (3), and the first normally closed contact and the second normally open contact are connected to the first switch (3) or the fourth power supply; The first driving unit (21) comprises a first transistor (Q5), a second transistor (Q4), a first diode (D1), a second diode (D2) and a first energy storage capacitor (EC1); wherein the first end of the first diode (D1) is connected to the first motor forward and reverse rotation control signal (S2), the second end of the first diode (D1) is respectively connected to the first end of the first energy storage capacitor (EC1), the first end of the second diode (D2) and the control end of the first transistor (Q5); the second end of the second diode (D2) is connected to the control end of the second transistor (Q4); the first end of the second transistor (Q4) is connected to the second end of the coil of the first relay (K1), the second end of the second transistor (Q4) is connected to the first end of the first transistor (Q5); the second end of the first transistor (Q5) and the second end of the first energy storage capacitor (EC1) are both connected to the ground wire; and / or, The second driving unit (22) comprises a third transistor (Q3), a fourth transistor (Q1), a third diode (D6), a fourth diode (D7) and a second energy storage capacitor (EC2); wherein the first end of the third diode (D6) is connected to the second motor forward and reverse control signal (S3), the second end of the third diode (D6) is respectively connected to the first end of the second energy storage capacitor (EC2), the first end of the fourth diode (D7) and the control end of the third transistor (Q3); the second end of the fourth diode (D7) is connected to the control end of the fourth transistor (Q1); the first end of the fourth transistor (Q1) is connected to the second end of the coil of the second relay (K2), the second end of the fourth transistor (Q1) is connected to the first end of the third transistor (Q3); the second end of the third transistor (Q3) and the second end of the second energy storage capacitor (EC2) are both connected to the ground wire; and / or, The third driving unit comprises a fifth transistor (Q6), a sixth transistor (Q7), a fifth diode (D9), a sixth diode (D10) and a third energy storage capacitor (EC3); wherein the first end of the fifth diode (D9) is connected to the third motor forward and reverse rotation control signal (S5), the second end of the fifth diode (D9) is respectively connected to the first end of the third energy storage capacitor (EC3), the first end of the sixth diode (D10) and the control end of the fifth transistor (Q6); the second end of the sixth diode (D10) is connected to the control end of the sixth transistor (Q7); the first end of the sixth transistor (Q7) is connected to the second end of the coil of the third relay (K3), the second end of the sixth transistor (Q7) is connected to the first end of the fifth transistor (Q6); the second end of the fifth transistor (Q6) and the second end of the third energy storage capacitor (EC3) are both connected to the ground wire.

2. The motor drive circuit according to claim 1, characterized in that: Also includes: Current limiting resistor; The current limiting resistor is connected in series to the control end of the first transistor (Q5) and / or the control end of the second transistor (Q4); and / or, The current limiting resistor is connected in series to the control end of the third transistor (Q3) and / or the control end of the fourth transistor (Q1); and / or, The current limiting resistor is connected in series to the control end of the fifth transistor (Q6) and / or the control end of the sixth transistor (Q7).

3. The motor drive circuit according to claim 1, characterized in that: Also includes: Prevent misleading on-resistance; The mis-turn-on prevention resistor is connected between the control end of the first transistor (Q5) and the second end of the first transistor (Q5); and / or, The mis-turn-on prevention resistor is connected between the control end of the third transistor (Q3) and the second end of the third transistor (Q3); and / or, The mis-turn-on prevention resistor is connected between the control end of the fifth transistor (Q6) and the second end of the fifth transistor (Q6).

4. The motor drive circuit according to claim 1, characterized in that: Also includes: Discharge resistor; The discharge resistor is connected in parallel with the first energy storage capacitor (EC1); and / or, The discharge resistor is connected in parallel with the second energy storage capacitor (EC2); and / or, The discharge resistor is connected in parallel with the third energy storage capacitor (EC3).

5. The motor drive circuit according to claim 1, characterized in that: It also includes protection capacitors and protection diodes; The protection capacitor is connected in series between the first motor forward and reverse control signal (S2) and the first diode (D1), the second end of the protection diode is connected to the first end of the first diode (D1), and the first end of the protection diode is connected to the ground wire; and / or, The protection capacitor is connected in series between the second motor forward and reverse control signal (S3) and the third diode (D6), the second end of the protection diode is connected to the first end of the third diode (D6), and the first end of the protection diode is connected to the ground wire; and / or, The protection capacitor is connected in series between the third motor forward and reverse control signal (S5) and the fifth diode (D9), the second end of the protection diode is connected to the first end of the fifth diode (D9), and the first end of the protection diode is connected to the ground wire.

6. The motor drive circuit according to claim 1, characterized in that: Also includes: A motor filter circuit is connected in parallel with the motor (M).

7. The motor drive circuit according to any one of claims 1 to 6, characterized in that: Also includes: A detection unit (4) is connected to the first switch (3) and is used to detect the current of the motor (M).

8. The motor drive circuit according to claim 7, characterized in that: The first switch (3) comprises a switch transistor (Q2), a first end of the switch transistor (Q2) is connected to the switching module, a second end of the switch transistor (Q2) is connected to the detection unit, and a control end of the switch transistor (Q2) is connected to a switch signal, wherein the switch signal comprises a PWM signal.

9. An electrical device, characterized in that: The invention comprises a motor driving circuit as claimed in any one of claims 1 to 8.

10. The electrical equipment according to claim 9, characterized in that: The electrical equipment includes a range hood.

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