Double rotor three-phase asynchronous motor and its starting method

Abstract

The double-rotor three-phase asynchronous motor of the present application can control the voltage value, voltage phase and time of the first phase terminal, the second phase terminal and the third phase terminal of the stator to control the starting process of the double-rotor three-phase asynchronous motor, thereby reducing the starting current and the maximum shaft torque in the starting process and the impact damage to the dragged mechanical and power distribution and control equipment. In the starting method of the present application, the first phase power supply, the second phase power supply and the third phase power supply are connected in sequence, and each power supply is connected according to the required voltage and phase, and the starting brake is started when the current of any one of the first phase power supply, the second phase power supply and the third phase power supply reaches the minimum value, so that the rotor speed gradually increases, thereby reducing the peak current of the starting of the double-rotor three-phase asynchronous motor of the present application and reducing the current impact on the control electrical appliances, power supply circuit and transformer connected with the double-rotor three-phase asynchronous motor.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more particularly to a dual-rotor three-phase asynchronous motor and its starting method. Background Technology

[0002] As is well known, existing three-phase asynchronous motors fix the stator to the frame and generate electromagnetic force to drive the rotor to rotate by energizing it. However, when the rotor is connected to a large external load, the motor needs to provide a large starting torque, which results in a large starting current when the motor drives the large external load, or even prevents it from starting, thus damaging the motor. When using a wound-rotor asynchronous motor for starting, multiple stages are needed to reduce the starting resistance. The large current of the rotor generates losses in the resistance, and the control equipment is relatively complex.

[0003] In addition, such as Figure 3 As shown by the lines in the diagram, existing three-phase asynchronous motors have a large peak current A1 during startup, which can easily cause a large current surge to the transformer and power supply circuit connected to the motor, resulting in the transformer and power supply circuit tripping and affecting startup efficiency.

[0004] Therefore, there is an urgent need for a dual-rotor three-phase asynchronous motor with higher starting efficiency and its starting method to overcome the above-mentioned defects. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-rotor three-phase asynchronous motor with higher starting efficiency.

[0006] Another objective of this invention is to provide a starting method with higher starting efficiency.

[0007] To achieve the above objectives, the present invention provides a dual-rotor three-phase asynchronous motor mounted on a frame. The dual-rotor three-phase asynchronous motor includes a rotor, a stator, and a brake. The rotor is rotatably mounted on the frame, and the stator is rotatably mounted on the frame. The rotor passes through the stator, and the brake is mounted between the stator and the frame. The dual-rotor three-phase asynchronous motor further includes a first-phase power supply for cooperating with the first-phase terminal of the stator, a second-phase power supply for cooperating with the second-phase terminal of the stator, a third-phase power supply for cooperating with the third-phase terminal of the stator, a first voltage detection module for detecting the voltage data of the first-phase power supply, and a voltage detection module for detecting the voltage data of the second-phase power supply. The system includes a second voltage detection module for detecting voltage data, a third voltage detection module for detecting voltage data of the third phase power supply, and a power control module for receiving voltage data detected by the first, second, and third voltage detection modules. The first voltage detection module is electrically connected to the power control module and the first phase power supply, the second voltage detection module is electrically connected to the power control module and the second phase power supply, and the third voltage detection module is electrically connected to the power control module and the third phase power supply. The power control module controls the connection and disconnection between the first phase power supply and the first phase terminal, between the second phase power supply and the second phase terminal, and between the third phase power supply and the third phase terminal.

[0008] Preferably, the dual-rotor three-phase asynchronous motor of the present invention further includes a current detection module for detecting current data and a brake control module for receiving the current data detected by the current detection module. The current detection module is electrically connected to one of the first phase power supply, the second phase power supply, and the third phase power supply. The brake control module is electrically connected to the current detection module and to the brake. The brake control module is also used to control the braking torque of the brake.

[0009] Preferably, the first axial end of the stator is rotatably mounted on the frame via a first shaft, the axial end of the rotor near the first shaft is rotatably inserted into the first axial end of the stator via a second shaft, and the axial end of the rotor away from the first shaft is rotatably inserted through the second axial end of the stator via a third shaft and mounted on the frame.

[0010] Preferably, the first axis, the second axis, and the third axis are aligned with each other.

[0011] To achieve the above objectives, the starting method of the dual-rotor three-phase asynchronous motor of the present invention includes the following steps:

[0012] Step 1: Detect the voltage phase of the first phase power supply and determine whether the voltage phase has crossed from negative zero. If not, the power control module keeps the first phase power supply disconnected from the first phase terminal. If yes, the power control module controls the first phase power supply to connect to the first phase terminal.

[0013] Step 2: Detect the voltage values ​​of the first and second phase power supplies, and determine whether the voltage values ​​of the first and second phase power supplies are equal. If not, the power control module keeps the second phase power supply disconnected from the second phase terminal; if so, the power control module controls the second phase power supply to connect to the second phase terminal.

[0014] Step 3: Detect the voltage phase of the third phase power supply and determine whether the voltage phase has crossed from negative zero. If not, the power control module keeps the third phase source disconnected from the third phase terminal. If yes, the power control module controls the third phase source to connect to the third phase terminal.

[0015] Preferably, the starting method of the dual-rotor three-phase asynchronous motor of the present invention further includes the following steps:

[0016] Step 4: Determine whether the current detected by the current detection module has reached the minimum value. If not, the brake control module keeps the brake from applying braking torque to the stator. If so, the brake control module controls the brake to apply braking torque to the stator until the stator stops rotating.

[0017] Compared with the prior art, the dual-rotor three-phase asynchronous motor of the present invention can control the voltage value, voltage phase and timing of the power supply connected to the first phase terminal, the second phase terminal and the third phase terminal of the stator, so as to further precisely control the starting process of the dual-rotor three-phase asynchronous motor, thereby further reducing the starting current and maximum shaft torque during the starting process, as well as the impact damage to the driven machinery and power distribution and control equipment. In addition, since the starting method of the dual-rotor three-phase asynchronous motor of the present invention connects the first phase power supply, the second phase power supply and the third phase power supply in sequence, and ensures that each power supply is connected according to the required voltage and phase, and the brake is activated when the current of any one of the first phase power supply, the second phase power supply and the third phase power supply reaches a minimum value, so that the rotor speed gradually increases, thereby reducing the peak current of the starting of the dual-rotor three-phase asynchronous motor of the present invention and reducing the current impact on the control electrical appliances, power supply circuit and transformer connected to the dual-rotor three-phase asynchronous motor. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the internal structure of the dual-rotor three-phase asynchronous motor of the present invention.

[0019] Figure 2 This is a flowchart of the starting method for the dual-rotor three-phase asynchronous motor of the present invention.

[0020] Figure 3 This is a graph showing the change of current over time in the dual-rotor three-phase asynchronous motor of the present invention. Detailed Implementation

[0021] Please see Figure 1 The dual-rotor three-phase asynchronous motor 1 of the present invention is mounted on a frame 2 to provide support for the dual-rotor three-phase asynchronous motor 1. The dual-rotor three-phase asynchronous motor 1 includes a rotor 10, a stator 20, and a brake 30. The rotor 10 is rotatably mounted on the frame 2, and the stator 20 is rotatably mounted on the frame 2, with the rotor 10 passing through the stator 20. The brake 30 is mounted between the stator 20 and the frame 2, so that during the starting process of the dual-rotor three-phase asynchronous motor 1 of the present invention, both the rotor 10 and the stator 20 can rotate relative to the frame 2, avoiding starting difficulties caused by excessive load on the rotor 1. The brake 30 can apply braking torque to the stator 20 to reduce the speed of the stator 20 and smoothly increase the speed of the rotor 10, thereby facilitating the control of the starting process of the dual-rotor three-phase asynchronous motor 1, reducing the starting current and maximum shaft torque during the starting process, and reducing the impact damage to the driven machinery and power distribution and control equipment caused by the dual-rotor three-phase asynchronous motor 1 of the present invention during the starting process. More specifically, as follows:

[0022] like Figure 1As shown, the dual-rotor three-phase asynchronous motor 1 also includes a first-phase power supply 41, a second-phase power supply 42, a third-phase power supply 43, a first voltage detection module 51, a second voltage detection module 52, a third voltage detection module 53, and a power control module 60. The first voltage detection module 51 is electrically connected to the power control module 60 and the first phase power supply 41, respectively, so that the first voltage detection module 51 detects the voltage data of the first phase power supply 41 and transmits the voltage data to the power control module 60; the second voltage detection module 52 is electrically connected to the power control module 60 and the second phase power supply 42, respectively, so that the second voltage detection module 52 detects the voltage data of the second phase power supply 42 and transmits the voltage data to the power control module 60; the third voltage detection module 53 is electrically connected to the power control module 60 and the third phase power supply 43, respectively, so that the third voltage detection module 53 detects the voltage data of the third phase power supply 43 and transmits the voltage data to the power control module 60; thus, the power control module 60 can receive the voltage data of the first phase power supply 41, the second phase power supply 42, and the third phase power supply 43. Furthermore, since the first phase power supply 41 is used to connect to the first phase terminal 20a of the stator 20... In conjunction with the first phase power supply 41, the power control module 60 controls the connection and disconnection between the first phase power supply 41 and the first phase terminal 20a; and the second phase power supply 42 is used to cooperate with the second phase terminal 20b of the stator 20, and the power control module 60 controls the connection and disconnection between the second phase power supply 42 and the second phase terminal 20b; and the third phase power supply 43 is used to cooperate with the third phase terminal 20c of the stator 20, and the power control module 60 controls the connection and disconnection between the third phase power supply 43 and the third phase terminal 20c, so that the power control module 60 can selectively control the connection and disconnection between the first phase power supply 41 and the first phase terminal 20a, the second phase power supply 42 and the second phase terminal 20b, and the third phase power supply 43 and the third phase terminal 20c according to the voltage data of the first phase power supply 41, the second phase power supply 42, and the third phase power supply 43, respectively, thereby facilitating further precise control of the starting process of the dual-rotor three-phase asynchronous motor 1, but not limited thereto.

[0023] like Figure 1As shown, the dual-rotor three-phase asynchronous motor 1 of the present invention further includes a current detection module 70 and a brake control module 80. The current detection module 70 is electrically connected to one of the first-phase power supply 41, the second-phase power supply 42, and the third-phase power supply 43. The brake control module 80 is electrically connected to the current detection module 70 so that the current detection module 70 detects the current data of the corresponding power supply and transmits the data to the brake control module 80. Furthermore, the brake control module 80 is electrically connected to the brake 30 so that the brake control module 80 controls the braking torque of the brake 30. This further facilitates the brake control module 80 in controlling the braking torque of the brake 30 based on the current data detected by the current detection module 70, thereby further precisely controlling the starting process of the dual-rotor three-phase asynchronous motor 1, though this is not a limitation.

[0024] like Figure 1 As shown, the first axial end 21 of the stator 20 is rotatably mounted on the frame 2 via the first shaft 91. The axial end 11 of the rotor 10 near the first shaft 91 is rotatably inserted into the first axial end 21 of the stator 20 via the second shaft 92. The axial end 12 of the rotor 10 away from the first shaft 91 is rotatably passed through the second axial end 22 of the stator 20 via the third shaft 93 and mounted on the frame 2, so as to ensure that any two of the rotor 10, stator 20 and frame 2 can rotate relative to each other. Preferably, the first shaft 91, the second shaft 92 and the third shaft 93 are aligned with each other to further ensure that the relative rotation between any two of the rotor 10, stator 20 and frame 2 is more stable and reliable, but this is not a limitation.

[0025] like Figure 1 and 2 As shown, the starting method of the dual-rotor three-phase asynchronous motor 1 of the present invention includes the following steps:

[0026] Step 1: The first voltage detection module 51 detects the voltage phase of the first phase power supply 41. The power control module 60 determines whether the voltage phase has crossed from negative zero. If not, the power control module 60 keeps the first phase power supply 41 from being connected to the first phase terminal 20a. If yes, the power control module 60 controls the first phase power supply 41 to be connected to the first phase terminal 20a. Of course, depending on the actual situation, the first voltage detection module 51 can also determine whether the voltage phase of the first phase power supply 41 has crossed from negative zero, so this is not a limitation.

[0027] Step 2: The first voltage detection module 51 detects the voltage value of the first phase power supply 41, and the second voltage detection module 52 detects the voltage value of the second phase power supply 42. The power control module 60 determines whether the voltage value of the first phase power supply 41 is equal to the voltage value of the second phase power supply 42. If not, the power control module 60 keeps the second phase power supply 42 disconnected from the second phase terminal 20b. If yes, the power control module 60 controls the second phase power supply 42 to connect to the second phase terminal 20b. Of course, depending on the actual situation, the second voltage detection module 52 can also determine whether the voltage value of the first phase power supply 41 is equal to the voltage value of the second phase power supply 42. In this case, the first voltage detection module 51 needs to transmit the detected voltage value of the first phase power supply 41 to the second voltage detection module 52. Alternatively, the first voltage detection module 51 can determine whether the voltage value of the first phase power supply 41 is equal to the voltage value of the second phase power supply 42. In this case, the second voltage detection module 52 needs to transmit the detected voltage value of the second phase power supply 42 to the first voltage detection module 51. Therefore, this is not a limitation.

[0028] Step 3: The third voltage detection module 53 detects the voltage phase of the third phase power supply 43. The power control module 60 determines whether the voltage phase has crossed from negative zero. If not, the power control module 60 keeps the third phase power supply 43 from being connected to the third phase terminal 20c. If yes, the power control module 60 controls the third phase power supply 43 to be connected to the third phase terminal 20c. Of course, depending on the actual situation, the third voltage detection module 53 can also determine whether the voltage phase of the third phase power supply 43 has crossed from negative zero, so this is not a limitation.

[0029] The above three steps reduce the peak starting current of the dual-rotor three-phase asynchronous motor 1 of the present invention, thereby reducing the current surge to the control electrical appliances, power supply circuit and transformer connected to the dual-rotor three-phase asynchronous motor 1.

[0030] like Figure 1 and 2 As shown, the starting method of the dual-rotor three-phase asynchronous motor 1 of the present invention further includes: step 4, the brake control module 80 determines whether the current detected by the current detection module 70 has reached a minimum value. If not, the brake control module 80 keeps the brake 30 from applying braking torque to the stator 20. If so, the brake control module 80 controls the brake 30 to apply braking torque to the stator 20 until the stator 20 stops rotating. Of course, depending on the actual situation, the current detection module 70 can also determine whether the current detected by the current detection module 70 has reached a minimum value, and this is not a limitation.

[0031] Step 4 is to gradually increase the speed of the rotor 10 by reducing the speed of the stator 20 after the stator 20 reaches its maximum speed, so as to smoothly increase the speed of the rotor 10 to the maximum and complete the starting process of the dual-rotor three-phase asynchronous motor 1. This further reduces the starting current and maximum shaft torque during the starting process, as well as the impact damage to the driven machinery and power distribution and control equipment.

[0032] right Figure 3 The explanation is as follows:

[0033] Line B represents the current change of the first phase power supply 41 during the starting process of the dual-rotor three-phase asynchronous motor 1 of the present invention using the starting method of the present invention. Point B1 represents the peak current in the current change represented by line B, and point B2 represents the current when the brake applies braking torque to the stator in the current change represented by line B.

[0034] Line A represents the change in current of the first phase power supply 41 after the dual-rotor three-phase asynchronous motor 1 of the present invention is simultaneously connected to the first phase power supply 41, the second phase power supply 42 and the third phase power supply 43. Point A1 represents the peak current in the current change represented by line A.

[0035] Depend on Figure 3 It can be seen that point B1 is lower than point A1, that is, the starting method of the present invention reduces the peak current during the starting process of the dual-rotor three-phase asynchronous motor 1 of the present invention.

[0036] It should be noted that the minimum value of current I is the current when current I changes from large to small and then from small to large. Furthermore, voltage data includes, but is not limited to, voltage value, voltage direction, and voltage phase; current data includes, but is not limited to, current value, current direction, and current phase. The starting peak current of the motor is the maximum current of the motor during the starting process.

[0037] Compared with the prior art, the dual-rotor three-phase asynchronous motor 1 of the present invention can control the voltage value, voltage phase and timing of the power supply connected to the first phase terminal 20a, the second phase terminal 20b and the third phase terminal 20c of the stator 20, so as to further accurately control the starting process of the dual-rotor three-phase asynchronous motor 1, thereby further reducing the starting current and maximum shaft torque during the starting process, as well as the impact damage to the driven machinery and power distribution and control equipment. In addition, in the starting method of the dual-rotor three-phase asynchronous motor 1 of the present invention, the first phase power supply 41, the second phase power supply 42 and the third phase power supply 43 are connected in sequence, and each power supply is connected according to the required voltage and phase. When the current of any one of the first phase power supply 41, the second phase power supply 42 and the third phase power supply 43 reaches the minimum value, the starting brake 30 is activated, so that the rotor speed 10 gradually increases. This can reduce the peak current of the dual-rotor three-phase asynchronous motor 1 of the present invention during starting, and reduce the current impact on the control electrical appliances, power supply circuit and transformer connected to the dual-rotor three-phase asynchronous motor 1.

[0038] The above-disclosed examples are merely preferred embodiments of the present invention, intended to facilitate understanding and implementation by those skilled in the art. They should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A dual-rotor three-phase asynchronous motor, mounted on a frame, comprising a rotor, a stator, and a brake, wherein the rotor is rotatably mounted on the frame, the stator is rotatably mounted on the frame, the rotor passes through the stator, the brake is mounted between the stator and the frame, a first axial end of the stator is rotatably mounted on the frame via a first shaft, an axial end of the rotor near the first shaft passes rotatably through the first axial end of the stator via a second shaft, and an axial end of the rotor away from the first shaft passes rotatably through the second axial end of the stator via a third shaft and is mounted on the frame, characterized in that... The dual-rotor three-phase asynchronous motor further includes a first-phase power supply for cooperating with the first phase terminal of the stator, a second-phase power supply for cooperating with the second phase terminal of the stator, a third-phase power supply for cooperating with the third phase terminal of the stator, a first voltage detection module for detecting voltage data of the first-phase power supply, a second voltage detection module for detecting voltage data of the second-phase power supply, a third voltage detection module for detecting voltage data of the third-phase power supply, and a power control module for receiving the voltage data detected by the first, second, and third voltage detection modules. The first voltage detection module is electrically connected to both the power control module and the first-phase power supply. The system includes: a power control module electrically connected to the power supply control module and the second phase power supply, and a third voltage detection module electrically connected to both the power supply control module and the third phase power supply. The power control module controls the connection and disconnection between the first phase power supply and the first phase terminal, between the second phase power supply and the second phase terminal, and between the third phase power supply and the third phase terminal. The system also includes: a current detection module for detecting current data, electrically connected to one of the first, second, and third phase power supplies; and a brake control module for receiving the current data detected by the current detection module, electrically connected to the current detection module and the brake, and the brake control module is also used to control the braking torque of the brake.

2. The dual-rotor three-phase asynchronous motor as described in claim 1, characterized in that, The first axis, the second axis, and the third axis are aligned with each other.

3. A starting method for a dual-rotor three-phase asynchronous motor as described in claim 1, characterized in that, The starting method includes the following steps: Step 1: Detect the voltage phase of the first phase power supply and determine whether the voltage phase has crossed from negative to zero. If not, the power control module keeps the first phase power supply disconnected from the first phase terminal. If yes, the power control module controls the first phase power supply to connect to the first phase terminal. Step 2: Detect the voltage values ​​of the first and second phase power supplies, and determine whether the voltage values ​​of the first and second phase power supplies are equal. If not, the power control module keeps the second phase power supply disconnected from the second phase terminal; if so, the power control module controls the second phase power supply to connect to the second phase terminal. Step 3: Detect the voltage phase of the third phase power supply and determine whether the voltage phase has crossed from negative zero. If not, the power control module keeps the third phase source disconnected from the third phase terminal. If yes, the power control module controls the third phase source to connect to the third phase terminal.

4. The starting method for a dual-rotor three-phase asynchronous motor as described in claim 3, characterized in that, The starting method further includes the following steps: Step 4: Determine whether the current detected by the current detection module has reached the minimum value. If not, the brake control module keeps the brake from applying braking torque to the stator. If so, the brake control module controls the brake to apply braking torque to the stator until the stator stops rotating.

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