Apparatus and method for controlling a motor

Abstract

An apparatus and method for controlling a motor are provided. The apparatus includes: a switch connected to a power source and configured to close and open a circuit; a relay connected to the motor and configured to switch the polarity of the motor by switching the connection of its contacts; and a controller connected to the switch and the relay and configured to control the closing and opening of the switch and control the connection of the relay with the contacts. Therefore, the solution for controlling a motor according to embodiments of the present invention has a simple structure and low cost.

Description

Technical Field

[0001] This invention relates to an apparatus and method for controlling the rotation of a motor, and more specifically, to an apparatus and method for controlling the forward and reverse rotation and braking of a motor. Background Technology

[0002] Currently, there are two main methods for switching forward and reverse rotation of DC brushed motors: the first method uses an H-bridge, which can control the on / off state of four drive transistors to achieve forward / reverse switching and motor braking; the second method uses relays, which also easily achieves forward / reverse switching.

[0003] However, the H-bridge driver scheme requires four power transistors, and because the four power transistors have different turn-on voltages, an H-bridge driver chip is also needed, resulting in a complex structure and high cost. Furthermore, due to the driving voltage limitations, the H-bridge is unsuitable for high-voltage applications. Additionally, motor braking using relays is not as easy to implement as using an H-bridge.

[0004] Furthermore, in some applications, the structure reciprocates under the drive of a motor, requiring the motor to switch between forward and reverse operation. During this switching, the motor must stop before rotating in the opposite direction, which leads to two problems: excessively long switching time; and uncertain gear stopping positions, which can easily cause gear jamming.

[0005] Therefore, a solution for controlling motors that is simple in structure and reduces costs is needed. Summary of the Invention

[0006] According to one aspect of an embodiment of the present invention, an apparatus for controlling a motor is provided, comprising: a switch connected to a power source and configured to close and open a circuit; a relay connected to the motor and configured to switch the polarity of the motor by switching the connection of contacts; and a controller connected to the switch and the relay and configured to control the closing and opening of the switch and control the connection of the relay with the contacts.

[0007] In one example, the relay is a double-pole double-throw relay.

[0008] In one example, the device further includes a freewheeling diode connected between the first set of contacts and the second set of contacts of the relay.

[0009] In one example, the relay is configured to connect to the first set of contacts, the switch is closed, and the motor operates in the forward direction.

[0010] In one example, the relay is configured to connect to the second set of contacts, the switch is closed, and the motor reverses.

[0011] In one example, the relay is also configured to switch the connection with the first set of contacts to the second set of contacts, or switch the connection with the second set of contacts to the first set of contacts, when the switch is opened, wherein the direction of the current generated by the motor after the switch is opened is opposite to the direction of the input current in the circuit.

[0012] In one example, the anode of the freewheeling diode is connected to the cathode of the power supply, and the cathode of the freewheeling diode is connected to the anode of the power supply.

[0013] In one example, when the switch is turned off during forward operation of the motor, the relay is configured to switch to connection with the second set of contacts, the freewheeling diode is turned on, and the motor is braked in the forward direction.

[0014] In one example, when the switch is opened during motor reverse operation, the relay is configured to switch to connection with the first set of contacts, the freewheeling diode is turned on, and the motor is braked in reverse.

[0015] According to another aspect of the present invention, a method for controlling a motor is provided, comprising: connecting a relay to a first set of contacts; closing a switch to control the motor to enter a first operating state; opening the switch; and connecting the relay to a second set of contacts to control the motor to brake.

[0016] In one example, controlling the motor braking includes: the motor being maintained in a first operating state for a period of time, generating a current in the opposite direction to the input current in the circuit after the switch is turned off, and wherein a freewheeling diode connected to a relay is turned on, forming a loop between the motor and the freewheeling diode.

[0017] In one example, the method further includes: closing the switch again to control the motor to enter a second operating state, wherein the first operating state is one of forward operation and reverse operation, and the second operating state is the other of forward operation and reverse operation.

[0018] According to another aspect of the embodiments of the present invention, an electric control is provided, including the aforementioned means for controlling a motor.

[0019] Therefore, the solution for controlling the motor according to the embodiments of the present invention has a simple structure and low cost.

[0020] Furthermore, when switching between forward and reverse directions, the relay switching time can be reduced, the switching time can be shortened, and the probability of gear jamming can be decreased. Attached Figure Description

[0021] The invention will be more readily understood from the following detailed description with reference to the accompanying drawings, wherein like reference numerals designate units of the same structure, and wherein:

[0022] Figure 1 This is a schematic circuit diagram illustrating a device for controlling a motor according to the prior art;

[0023] Figure 2 This is a schematic circuit diagram illustrating a device for controlling a motor according to an embodiment of the present invention;

[0024] Figure 3 A schematic circuit diagram of a motor control device 300 including a freewheeling diode according to an embodiment of the present invention is shown.

[0025] Figure 4 A schematic diagram illustrating forward rotation and braking performed by a device for controlling a motor according to an embodiment of the present invention is shown.

[0026] Figure 5 A schematic signal diagram illustrating the forward rotation and braking operation of a motor according to an embodiment of the present invention;

[0027] Figure 6 A schematic diagram illustrating the reversing operation and braking performed by a device for controlling a motor according to an embodiment of the present invention is shown.

[0028] Figure 7 A schematic signal diagram illustrating the reverse operation and braking of a motor according to an embodiment of the present invention; and

[0029] Figure 8 A schematic flowchart of a method for controlling a motor according to an embodiment of the present invention is shown. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Furthermore, it should be noted that in this specification, A connected to B can mean "A is directly connected to B" or "A is connected to B via other middleware". A connected between B and C can mean "A is directly connected to both A and B" or "A is connected to both B and C via other middleware".

[0032] Figure 1 This is a schematic circuit diagram illustrating a device for controlling a motor according to the prior art.

[0033] Figure 1 This illustrates a prior art solution using an H-bridge driver. For example... Figure 1As shown, the scheme using an H-bridge to drive the motor for forward and reverse rotation and braking requires four power transistors. Furthermore, because the four power transistors have different on-state voltages, an H-bridge driver chip is also needed. Therefore, the structure is complex and the cost is high.

[0034] Figure 2 This is a schematic circuit diagram illustrating a device 200 for controlling a motor according to an embodiment of the present invention.

[0035] like Figure 2 As shown, device 200 may include switch S1, relay 201 and controller 202.

[0036] Switch S1 can be connected to a power source and can be configured to close and open the circuit. Relay 201 can be connected to motor M and can be configured to switch the polarity of the motor by switching the connection of its contacts. Controller 202 can be connected to switch S1 and relay 202 and can be configured to control the closing and opening of switch S1 and control the connection of relay 201 with its contacts.

[0037] Therefore, the device for controlling the motor according to the embodiments of the present invention only requires a switch, a relay and a controller to control the forward and reverse switching of the motor, which is simple in structure and low in cost.

[0038] In one example, relay 201 could be a double-pole double-throw relay.

[0039] The device for controlling a motor according to an embodiment of the present invention may further include a freewheeling diode.

[0040] Figure 3 A schematic circuit diagram of a motor control device 300 including a freewheeling diode according to an embodiment of the present invention is shown.

[0041] like Figure 3 As shown, in addition to switch S1, relay 201 and controller 202, device 300 also includes freewheeling diode D1, which can be connected between the first set of contacts 1-1' and the second set of contacts 2-2' of relay 201 and connected to a power supply.

[0042] In one example, the positive terminal of the freewheeling diode D1 is connected to the negative terminal of the power supply, and the negative terminal of the freewheeling diode D1 is connected to the positive terminal of the power supply.

[0043] In one example, the device for controlling a motor according to an embodiment of the present invention can be applied to both high-voltage DC motors and low-voltage DC motors.

[0044] From then on, it will be Figure 3 Taking the schematic circuit shown as an example, the specific operation of the device for controlling a motor according to an embodiment of the present invention will be described in detail.

[0045] Forward rotation operation and braking

[0046] Figure 4 A schematic diagram is shown illustrating forward rotation and braking performed by a device for controlling a motor according to an embodiment of the present invention.

[0047] like Figure 4 As shown in the upper part, when the relay coil is not energized, it is in its default position and configured to connect with the first set of contacts 1-1'. Then, the controller controls the switch S1 to close, and the motor rotates forward. As shown in the figure, during forward rotation, the current in the circuit flows clockwise, as... Figure 4 As indicated by the thick arrow at the top, and the motor rotates clockwise, as... Figure 4 As indicated by the thin arrow at the top.

[0048] During the forward rotation of the motor, the freewheeling diode D1 is reverse-biased and cut off.

[0049] According to an embodiment of the present invention, switch S1 is used to control the opening and closing of the motor, ensuring that switching occurs after the relay has completed its operation, and ensuring that the relay does not switch under load.

[0050] When braking of the motor is required, switch S1 is disconnected under the control of the controller. The controller controls the relay to switch the connection with the contacts, thereby switching the polarity of the motor.

[0051] In one example, when switch S1 is opened, the relay switches its connection from the first set of contacts 1-1' to the second set of contacts 2-2', or vice versa. At this time, because the polarity is switched, but the motor maintains its original direction of rotation due to inertia, the direction of the current generated by the motor after the switch is opened is opposite to the direction of the input current in the circuit.

[0052] like Figure 4 As shown in the lower part, when switch S1 is opened during forward rotation of the motor, the relay can switch the connection with the first set of contacts 1-1' to the second set of contacts 2-2'. Due to inertia, the motor continues to rotate clockwise for a period of time, in the direction shown... Figure 4 As indicated by the thin arrow at the bottom.

[0053] At this time, the motor continues to rotate clockwise due to inertia, acting like a generator. The current it generates is opposite to the input current, and the freewheeling diode D1 is turned on by the input current. The motor and the freewheeling diode D1 form a circuit, and the motor's energy is rapidly dissipated through its own resistance, thus braking the motor during forward rotation. The direction of the input current is as follows... Figure 4 As indicated by the thick arrow at the bottom.

[0054] When the motor is braked during forward rotation, the controller can close switch S1 again to reverse the motor, thus achieving forward-reverse switching of the motor.

[0055] Therefore, according to embodiments of the present invention, during forward / reverse switching, the relay switching time can be reduced, the switching time can be decreased, and the probability of gear jamming can be reduced.

[0056] Figure 5 A schematic signal diagram illustrating the forward rotation and braking operation of a motor according to an embodiment of the present invention is shown.

[0057] like Figure 5 As shown, in the default state, the relay coil is not energized, and the relay is in the default position, i.e., connected to the first set of contacts 1-1'. After switch S1 is closed, the motor enters forward rotation. When switch S1 is opened, after a certain period of time, such as the freewheeling time of the inductor in the motor (5ms), the relay switches to connection with the second set of contacts 2-2', thereby achieving motor braking.

[0058] Figure 5 The motor braking time shown is 100ms; however, this is merely an example, and the embodiments of the present invention are not limited thereto.

[0059] Reverse operation and braking

[0060] Figure 6 A schematic diagram is shown illustrating the reversing operation and braking performed by a device for controlling a motor according to an embodiment of the present invention.

[0061] like Figure 6 As shown in the upper part, when the relay coil is energized, it is configured to connect with the second set of contacts 2-2'. Then, the controller controls the switch S1 to close, and the motor reverses. As shown in the figure, during the reverse operation, the current in the circuit flows counterclockwise, as... Figure 6 As indicated by the thick arrow at the top, and the motor rotates counterclockwise, as... Figure 6 As indicated by the thin arrow at the top.

[0062] As mentioned earlier, switch S1 is used to control the starting and stopping of the motor, ensuring that switching occurs after the relay has completed its operation, and ensuring that the relay does not switch under load.

[0063] When braking of the motor is required, switch S1 is disconnected, and the controller controls the relay to switch the connection with the contacts, thereby switching the polarity of the motor.

[0064] In one example, when switch S1 is opened, the relay switches its connection from the second set of contacts 2-2' to the first set of contacts 1-1', or vice versa. Similar to the forward rotation of a motor, the polarity is switched, but the motor maintains its original direction of rotation due to inertia. Therefore, the direction of the current generated by the motor after the switch is opened is opposite to the direction of the input current in the circuit.

[0065] like Figure 6 As shown in the lower part, when switch S1 is opened during motor reverse operation, the relay can switch the connection with the second set of contacts 2-2' to the first set of contacts 1-1'. Due to inertia, the motor continues to rotate counterclockwise for a period of time, in the direction shown... Figure 6 As indicated by the thin arrow at the bottom.

[0066] At this point, the motor continues to rotate counterclockwise due to inertia, while the input current is clockwise. Figure 6 As indicated by the thick arrow at the bottom.

[0067] Because the freewheeling diode D1 is turned on by the input current, the motor and the freewheeling diode D1 form a circuit, and the motor energy is quickly consumed through its own resistance, thus achieving the braking effect.

[0068] When the motor is braked during reverse operation, the switch S1 can be closed again by the controller, and the motor will start forward operation, thus realizing the reverse-forward switching of the motor.

[0069] Therefore, according to embodiments of the present invention, during reverse switching, the relay switching time can be reduced, the switching time can be decreased, and the probability of gear jamming can be reduced.

[0070] Figure 7 A schematic signal diagram illustrating the reverse operation and braking of a motor according to an embodiment of the present invention is shown.

[0071] like Figure 7 As shown, the relay coil is energized, i.e., connected to the second set of contacts 2-2'. After the relay is connected to the second set of contacts 2-2', for example, after a 20ms relay stabilization period, switch S1 is closed, and the motor enters reverse operation. When switch S1 is opened, after a period of time, for example, the inductor freewheeling period of 5ms in the motor, the relay switches to connection with the first set of contacts 1-1', thereby achieving motor braking.

[0072] Figure 7 The motor braking time shown is 100ms; however, this is merely an example, and the embodiments of the present invention are not limited thereto.

[0073] Therefore, the solution for controlling the motor according to embodiments of the present invention has a simple structure and low cost. Furthermore, during forward / reverse switching, it can reduce relay switching time, decrease switching time, and reduce the probability of gear jamming.

[0074] Figure 8 A schematic flowchart of a method 800 for controlling a motor according to an embodiment of the present invention is shown.

[0075] like Figure 8 As shown, in method 800, at step 801, the relay is connected to the first set of contacts. At step 802, the switch is closed, controlling the motor to enter the first operating state. At step 803, the switch is opened. At step 804, the relay is connected to the second set of contacts, controlling the motor to brake.

[0076] In one example, controlling the motor braking includes: the motor being maintained in a first operating state for a period of time, generating a current in the opposite direction to the input current in the circuit after the switch is turned off, and wherein a freewheeling diode connected to a relay is turned on, forming a loop between the motor and the freewheeling diode.

[0077] For example, the first operating state can be forward rotation, and controlling the motor braking can include: maintaining the motor in forward rotation and generating a current in the opposite direction to the input current in the circuit after the switch is turned off. At this time, the freewheeling diode connected to the relay is turned on by the input current, forming a circuit between the motor and the freewheeling diode. The motor energy is quickly dissipated through its own resistance, achieving the braking effect.

[0078] For example, the first operating state can be reversed, and controlling the motor braking can include: maintaining the motor in reverse operation and generating a current in the opposite direction to the input current in the circuit after the switch is turned off. At this time, the freewheeling diode connected to the relay is turned on by the input current, forming a circuit between the motor and the freewheeling diode. The motor energy is quickly dissipated through its own resistance, achieving the braking effect.

[0079] In one example, method 800 may further include: closing the switch again to control the motor to enter a second operating state, wherein the first operating state is one of forward operation and reverse operation, and the second operating state is the other of forward operation and reverse operation.

[0080] By closing the switch again, the motor can be switched between forward and reverse rotation.

[0081] Therefore, the solution for controlling the motor according to embodiments of the present invention has a simple structure and low cost. Furthermore, during forward / reverse switching, it can reduce relay switching time, decrease switching time, and reduce the probability of gear jamming.

[0082] Those skilled in the art will recognize that the units and algorithm steps of the various embodiments described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each embodiment have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0083] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0084] In the embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0085] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0086] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0087] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0088] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A device for controlling an electric motor, comprising: A switch, connected to a power source, is configured to close and open a circuit; A relay, connected to a motor, is configured to switch the polarity of the motor by switching the connection of its contacts; as well as The controller, connected to the switch and relay, is configured to control the closing and opening of the switch and the connection between the relay and the contacts.

2. The apparatus of claim 1, wherein, The relay is a double-pole double-throw relay.

3. The apparatus according to claim 2, further comprising: A freewheeling diode is connected between the first set of contacts and the second set of contacts of the relay.

4. The apparatus of claim 3, wherein, The relay is configured to connect to the first set of contacts, the switch is closed, and the motor rotates in the forward direction.

5. The apparatus of claim 3, wherein, The relay is configured to connect to the second set of contacts, the switch is closed, and the motor reverses.

6. The apparatus of claim 4 or 5, wherein, The relay is also configured to: when the switch is open, switch the connection with the first set of contacts to the second set of contacts, or switch the connection with the second set of contacts to the first set of contacts. In this case, after the switch is turned off, the direction of the current generated by the motor is opposite to the direction of the input current in the circuit.

7. The apparatus of claim 6, wherein, The positive terminal of the freewheeling diode is connected to the negative terminal of the power supply, and the negative terminal of the freewheeling diode is connected to the positive terminal of the power supply.

8. The apparatus of claim 7, wherein, When the switch is turned off during forward operation of the motor, the relay is configured to switch to connection with the second set of contacts, the freewheeling diode is turned on, and the motor is braked in the forward direction.

9. The apparatus of claim 7, wherein, When the switch is opened during motor reverse operation, the relay is configured to switch to connection with the first set of contacts, the freewheeling diode is turned on, and the motor is braked in reverse.

10. A method for controlling a motor, comprising: Connect the relay to the first set of contacts; Close the switch to control the motor to enter the first operating state; Disconnect the switch; as well as Connect the relay to the second set of contacts to control the motor braking.

11. The method of claim 10, wherein, Controlling the motor braking includes: The motor is maintained in its first operating state for a period of time, generating a current in the opposite direction to the input current in the circuit after the switch is turned off, and In this circuit, the freewheeling diode connected to the relay is turned on, forming a loop between the motor and the freewheeling diode.

12. The method of claim 11, further comprising: Close the switch again to control the motor to enter the second operating state. The first operating state is one of forward rotation and reverse rotation, and the second operating state is the other of forward rotation and reverse rotation.

13. An electric control device comprising a means for controlling a motor according to any one of claims 1 to 9.

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