Motor forward and reverse switching circuit and motor control system

Abstract

The present invention relates to the technical field of water pump motor control, and discloses a motor forward and reverse switching circuit and a motor control system, comprising: a switching device, a working switch circuit, a forward switch circuit, a reverse switch circuit, a phase sequence switching circuit, and a measurement and protection device. When the motor needs to rotate forward, the switching device makes the motor power bus and the power bus have the same phase sequence, and the motor rotates forward. At the same time, the working switch circuit, the forward switch circuit, the reverse switch circuit, and the phase sequence switching circuit switch states, so that the measurement and protection device switches to a forward working condition. When the motor needs to reverse, the switching device makes the motor power bus and the power bus have opposite phase sequences, and the motor reverses. At the same time, the working switch circuit, the forward switch circuit, the reverse switch circuit, and the phase sequence switching circuit switch states, so that the measurement and protection device switches to a reverse working condition. The present invention only requires one set of switching circuits to automatically switch the direction of the motor, simplifying the system structure and reducing equipment costs.

Description

Technical Field

[0001] The present invention relates to the technical field of water pump motor control, and in particular to a motor forward and reverse switching circuit and a motor control system. Background Art

[0002] Some pump station projects require bidirectional operation, depending on the water levels on the inner and outer river sides. For example, during flood season, water needs to be pumped from the inner river to the outer river (drainage operation); during dry season, water from the outer river needs to be pumped to the inner river to maintain the required inner river water level. To meet this requirement, the direction of the pump's rotation is altered by changing the phase sequence of the three-phase power supply to the pump motor. For example, in forward operation, the phase sequence is ABC, and the pump rotates forward; in reverse operation, the phase sequence is CBA, and the pump rotates in the opposite direction.

[0003] Traditionally, if such water pumps are driven by 10kV motors, two 10kV motor switch cabinets are equipped for each water pump, one with ABC phase sequence on the outgoing line side and the other with CBA phase sequence on the outgoing line side. The two switch cabinets are connected in parallel at the outgoing line end and then connected to the motor junction box via cables. In this case, if Figure 1 As shown, each motor needs to be equipped with two switch cabinets, corresponding to two sets of primary main circuits and secondary measurement, control and protection equipment. Electrical interlocking must be implemented between the circuit breaker control circuits of the two switch cabinets to ensure that only one circuit breaker can be closed. The circuit structure is complex and the cost is high. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the forward and reverse rotation of the water pump motor requires two sets of control circuits, which leads to complex system structure and high cost, and thus provide a motor forward and reverse switching circuit and a motor control system.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a motor forward and reverse switching circuit, comprising: a switching device, a working switch circuit, a forward switch circuit, a reverse switch circuit, a phase sequence switching circuit and a measurement and protection device, wherein the switching device, a first end of which is connected to the power bus, a second end of which is connected to the power supply end of each motor through the motor power bus, and a third end of which is connected to the first end of the working switch circuit; the working switch circuit, a second end of which is connected to the first end of the forward switch circuit, and a third end of which is connected to the first end of the reverse switch circuit; the forward switch circuit, a second end of which is connected to the first end of the phase sequence switching circuit; the reverse switch circuit, a second end of which is connected to the second end of the phase sequence switching circuit; the phase sequence switching circuit, a third end of which is connected to the first end of the measurement and protection device, and a fourth end of which is connected to the power supply voltage small bus; the measurement and protection device, a second end of which is respectively connected to the measurement and protection ends of multiple motors, and is used to switch the working condition based on the phase sequence of its first end, thereby switching the internal current measurement phase sequence and switching the protection parameters according to the direction of rotation of each motor; when the motor needs to rotate forward, the switching device switches on The motor rotates forward after the phase sequence of the motor power bus is the same as the phase sequence of the power bus. At the same time, the working switch circuit is turned on based on the switch state of the switching device, so that the forward switch circuit is turned on and the reverse switch circuit is turned off. After that, the phase sequence switching circuit switches the switch state so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is the same as the phase sequence of the power voltage bus. Then, the measuring and protection device switches to the forward working condition. When the motor needs to be reversed, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus. Then, the motor reverses. Thereafter, the working switch circuit is turned on based on the switch state of the switching device, so that the reverse switch circuit is turned on and the forward switch circuit is turned off. After that, the phase sequence switching circuit switches the switch state so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is opposite to the phase sequence of the power voltage bus. Then, the measuring and protection device switches to the reverse working condition. The phase sequence of the power bus is consistent with the phase sequence of the power voltage bus.

[0007] The motor forward and reverse switching circuit provided by the present invention has the following characteristics: when the switching device makes the phase sequence of the motor power bus and the power bus the same, all motors start to rotate forward, and the forward switch circuit inside the motor forward and reverse switching circuit works; when the switching device makes the phase sequence of the motor power bus and the power bus opposite, all motors start to reverse, and the reverse switch circuit inside the motor forward and reverse switching circuit works, so that the phase sequence switching circuit switches the phase sequence of the voltage and current inside the measurement and protection device according to the switching status of the forward switch circuit and the reverse switch circuit, so that the measurement and protection device switches to the forward rotation condition according to the positive phase sequence of the motor and measures the working parameters of the forward rotating motor, or switches to the reverse rotation condition according to the reverse phase sequence of the motor and measures the working parameters of the reversed motor. Only one set of motor forward and reverse switching circuit is required to realize the forward and reverse control of all motors and the corresponding measurement and protection parameter switching, which greatly reduces the circuit cost and simplifies the structure of the overall motor control circuit.

[0008] In an optional embodiment, the working switch circuit includes: a control module, a first auxiliary switch and a second auxiliary switch, wherein the control module has a first end connected to the third end of the switching device, and its second end and third end are respectively connected to the first end of the first auxiliary switch and the first end of the second auxiliary switch; the second end of the first auxiliary switch is connected to the first end of the forward switch circuit; the second end of the second auxiliary switch is connected to the first end of the reverse switch circuit; when the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and the motor rotates forward. At the same time, the control module controls the first auxiliary switch to close and the second auxiliary switch to open based on the switch state of the switching device, so that the forward switch circuit is turned on and the reverse switch circuit is turned off; when the motor needs to reverse, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and the motor reverses. At the same time, the control module controls the second auxiliary switch to close and the first auxiliary switch to open based on the switch state of the switching device, so that the reverse switch circuit is turned on and the forward switch circuit is turned off.

[0009] The motor forward and reverse switching circuit provided by the present invention expands the number of auxiliary switches and connects different auxiliary switches in different circuits, thereby using one control module to achieve simultaneous control of the on and off of multiple circuits, simplifying the circuit structure and reducing the complexity of the control process.

[0010] In an optional embodiment, the phase sequence switching circuit includes: a first switch, a second switch, a third switch and a fourth switch, wherein the first switch, whose control end is connected to the second end of the forward switching circuit, whose first end is connected to the A phase of the power supply voltage busbar, and whose second end is connected to the A phase of the motor voltage busbar at the first end of the measuring and protection device; the second switch, whose control end is connected to the second end of the forward switching circuit, whose first end is connected to the C phase of the power supply voltage busbar, and whose second end is connected to the C phase of the motor voltage busbar at the first end of the measuring and protection device; the third switch, whose control end is connected to the second end of the reverse switching circuit, whose first end is connected to the A phase of the power supply voltage busbar, and whose second end is connected to the C phase of the motor voltage busbar at the first end of the measuring and protection device. ; A fourth switch, whose control end is connected to the second end of the reversing switch circuit, whose first end is connected to the C phase of the power supply voltage busbar, and whose second end is connected to the A phase of the motor voltage busbar at the first end of the measuring and protection device; the B phase of the power supply voltage busbar is directly connected to the B phase of the motor voltage busbar at the first end of the measuring and protection device; when the motor needs to rotate forward, the working switch circuit is turned on, the forward switch circuit is turned on, and the reversing switch circuit is turned off, so that the first switch and the second switch are turned on, and the third switch and the fourth switch are turned off; when the motor needs to reverse, the working switch circuit is turned on, the reversing switch circuit is turned on, and the forward switch circuit is turned off, so that the third switch and the fourth switch are turned on, and the first switch and the second switch are turned off.

[0011] In an optional embodiment, the measuring and protection device includes: a relay protection device, a first end of which is connected to the third end of the forward switch circuit, a second end of which is connected to the third end of the reverse switch circuit, a third end of which is connected to the third end of the phase sequence switching circuit, and a fourth end of which is respectively connected to the first measuring and protection end of a motor; when any motor fails, and / or the forward switch circuit fails, and / or the reverse switch circuit fails, the relay protection device cuts off the power supply to the corresponding motor based on the fault signal.

[0012] In an optional embodiment, the measurement and protection device further includes: a measuring meter, a first end of which is connected to the fourth end of the reversing switch circuit, a second end of which is connected to the third end of the phase sequence switching circuit, and a third end of which is respectively connected to the second measurement and protection end of a motor, and is used to measure the working parameters of each motor. In an optional embodiment, the forward rotation switch circuit includes: a first relay and a second relay, wherein the first relay has a first end connected to the second end of the working switch circuit and the first end of the second relay, and a second end connected to the first end of the relay protection device; the second relay has a second end connected to the first end of the phase sequence switching circuit; when the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward, and then the first relay and the second relay are energized and the reversing switch circuit is turned off; when the motor needs to reverse, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses, and then the first relay and the second relay are de-energized and the reversing switch circuit is turned on.

[0013] The motor forward and reverse switching circuit provided by the present invention utilizes a first relay and a second relay to switch on and off all relevant protection circuits and control circuits when the motor rotates forward, so that the timing at which each circuit starts working is consistent, reducing the difficulty of multi-circuit control and improving the response speed of the entire switching circuit.

[0014] In an optional embodiment, the reversing switch circuit includes: a third relay, a fourth relay and a fifth relay, wherein the first end of the third relay is connected to the second end of the working switch circuit, the first ends of the fourth relay and the fifth relay, and the second end is connected to the second end of the relay protection device; the second end of the fourth relay is connected to the first end of the measuring meter; the second end of the fifth relay is connected to the second end of the phase sequence switching circuit; when the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward, and then the forward switch circuit is turned on, and the third relay, the fourth relay and the fifth relay are de-energized; when the motor needs to reverse, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses, and then the forward switch circuit is turned off, and the third relay, the fourth relay and the fifth relay are energized.

[0015] The motor forward / reverse switching circuit provided by the present invention utilizes a third relay, a fourth relay, and a fifth relay to switch on and off all relevant protection circuits, measurement circuits, and control circuits when the motor is reversed, so that the timing at which each circuit starts working is consistent, reducing the difficulty of multi-circuit control and improving the response speed of the entire switching circuit.

[0016] In the second aspect, the present invention provides a motor control system, comprising: a forward isolation trolley, a reverse isolation trolley and the motor forward and reverse switching circuit of the first aspect, wherein the forward isolation trolley and the reverse isolation trolley are arranged in a switching device; the forward isolation trolley, whose input end is connected to the power bus, whose first output end is connected to the first end of the working switch circuit and the first output end of the reverse isolation trolley, whose second output end is connected to the second output end of the reverse isolation trolley through the motor power bus and the power supply end of multiple motors, which is used to directly input the power bus voltage to each motor; the reverse isolation trolley, whose input end is connected to the power bus, is used to reverse the phase sequence of the power bus voltage and then input it to each motor; when the motor needs to rotate forward, the forward isolation trolley is connected to the system so that the phase sequence of the motor power bus is consistent with that of the motor. After the phase sequence of the power bus is the same, the motor rotates forward, and at the same time the working switch circuit is turned on, so that the forward switch circuit is turned on and the reverse switch circuit is turned off, the phase sequence switching circuit switches the switch state, so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is the same as the phase sequence of the power voltage bus, and the measuring and protection device switches to the forward working condition; when the motor needs to reverse, the reverse isolation trolley is connected to the system, so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and the motor reverses, and at the same time the working switch circuit is turned on, so that the reverse switch circuit is turned on and the forward switch circuit is turned off, the phase sequence switching circuit switches the switch state, so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is opposite to the phase sequence of the power voltage bus, and the measuring and protection device switches to the reverse working condition.

[0017] The motor control system provided by the present invention has the following characteristics: when a forward isolation trolley is connected to the motor control system, all motors rotate forward, the forward switch circuit is turned on, and the reverse switch circuit is turned off; when a reverse isolation trolley is connected to the motor control system, all motors rotate reversely, the reverse switch circuit is turned on, and the forward switch circuit is turned off. Therefore, the operator only needs to change the type of isolation trolley connected to the motor control system, and the motor control system can automatically switch the on-off state of each internal circuit, thereby controlling the forward or reverse rotation of the motor.

[0018] In an optional embodiment, the A-phase input terminal, the B-phase input terminal and the C-phase input terminal of the reverse isolation trolley are respectively connected to the C-phase output terminal, the B-phase output terminal and the A-phase output terminal of the same through a metal busbar.

[0019] In an optional embodiment, the motor control system also includes: a monitoring system, whose input end is respectively connected to the fourth end of the forward switch circuit and the fifth end of the reverse switch circuit, and is used to alarm when the forward switch circuit and / or the reverse switch circuit fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a structural diagram of a specific circuit of a motor steering control circuit in the related art;

[0022] Figure 2 is a composition diagram of a specific example of a motor forward and reverse switching circuit according to an embodiment of the present invention;

[0023] Figure 3 is a composition diagram of a specific example of a working switch circuit according to an embodiment of the present invention;

[0024] Figure 4 is a composition diagram of another specific example of a motor forward and reverse switching circuit according to an embodiment of the present invention;

[0025] Figure 5 is a structural diagram of a specific circuit of a forward rotation switch circuit according to an embodiment of the present invention;

[0026] Figure 6 is a structural diagram of another specific circuit of the forward rotation switch circuit according to an embodiment of the present invention;

[0027] Figure 7 is a structural diagram of another specific circuit of the forward rotation switch circuit according to an embodiment of the present invention;

[0028] Figure 8 is a structural diagram of a specific circuit of a reversing switch circuit according to an embodiment of the present invention;

[0029] Figure 9 is a structural diagram of another specific circuit of the reversing switch circuit according to an embodiment of the present invention;

[0030] Figure 10 is a structural diagram of another specific circuit of the reversing switch circuit according to an embodiment of the present invention;

[0031] Figure 11 is a structural diagram of a specific circuit of a phase sequence switching circuit according to an embodiment of the present invention;

[0032] Figure 12 is a structural diagram of a specific circuit of a relay protection device and a measuring meter according to an embodiment of the present invention;

[0033] Figure 13is a structural diagram of another specific circuit of a relay protection device and a measuring meter according to an embodiment of the present invention;

[0034] Figure 14 is a composition diagram of a specific example of a motor control system according to an embodiment of the present invention;

[0035] Figure 15 FIG. 4 is a structural diagram of a specific circuit of a motor control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0039] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] In the control of a pump station, it is usually necessary to switch the direction of the motor in the station according to the different working requirements of the pump station, so as to drive the water pump to drain or divert water. To meet this requirement, it is necessary to change the direction of the water pump by changing the phase sequence of the three-phase incoming power supply of the water pump motor. Traditional control circuits such as Figure 1As shown, each motor needs to be equipped with two switch cabinets, and the corresponding other control circuits or protection devices are two sets. An electrical interlock must be set between the circuit breaker control circuits of the two switch cabinets to ensure that only one circuit breaker can be closed. This makes the entire control system structure complex and the cost high.

[0041] This embodiment provides a motor forward and reverse switching circuit that can be used to control the forward and reverse rotation of multiple motors in a pump station, such as Figure 2 As shown, it includes: a working switch circuit 1, a forward switch circuit 2, a reverse switch circuit 3, a phase sequence switching circuit 4, a measuring and protection device 5 and a switching device 6.

[0042] Figure 2 In the figure, the switching device 6 has a first end connected to the power bus, a second end connected to the power supply end of each motor (#1~#n) through the motor power bus, and a third end connected to the first end of the working switch circuit 1; the working switch circuit 1 has a first end connected to the power supply end of multiple motors (#1~#n), a first end input bus voltage, a second end connected to the first end of the forward switch circuit 2, and a third end connected to the first end of the reverse switch circuit 3.

[0043] Specifically, Figure 2 In the embodiment, when each motor (#1-#n) is required to rotate forward or reverse, the switching device 6 switches the switch state so that the phase sequence of the motor power bus is the same as or opposite to the phase sequence of the power bus, and then the motor begins to rotate forward or reverse. When the switching device 6 switches the switch state, the working switch circuit 1 is turned on based on the switch state of the switching device 6, indicating that the operating parameters of the multiple motors (#1-#n) need to begin forward rotation or reverse operation are measured. The working switch circuit 1 controls the internal switch to switch the on and off state based on the switch state of the switching device 6, so that the forward switch circuit 2 or the reverse switch circuit 3 begins to operate.

[0044] Specifically, Figure 3 In the embodiment, the working switch circuit 1 includes: a control module 11, a first auxiliary switch 12 and a second auxiliary switch 13, wherein the first end of the control module 11 is connected to the third end of the switching device 6, and the second end and the third end thereof are connected to the first end of the first auxiliary switch 12 and the first end of the second auxiliary switch 13 respectively; the second end of the first auxiliary switch 12 is connected to the first end of the forward switch circuit 2; and the second end of the second auxiliary switch 13 is connected to the first end of the reverse switch circuit 3.

[0045] Specifically, Figure 3In the example, when the motor needs to rotate forward, the switching device 6 in the primary circuit switches the switch state so that the motor power bus phase sequence is the same as the power bus phase sequence, and then the motor rotates forward. In the secondary circuit, the control module 11 controls the first auxiliary switch 12 to close and the second auxiliary switch 13 to disconnect based on the switch state of the switching device 6, so that the forward switch circuit 2 is turned on and the reverse switch circuit 3 is turned off; when the motor needs to reverse, the switching device 6 in the primary circuit switches the switch state so that the motor power bus phase sequence is opposite to the power bus phase sequence, and then the motor reverses. In the secondary circuit, the control module 11 controls the second auxiliary switch 13 to close and the first auxiliary switch 12 to disconnect based on the switch state of the switching device 6, so that the reverse switch circuit 3 is turned on and the forward switch circuit 2 is turned off.

[0046] Optionally, when the control module 11 is a relay, the first auxiliary switch 12 and the second auxiliary switch 13 are auxiliary contacts of the relay. The control module 11 may also be a voltage divider device that changes the voltage at its second terminal based on the bus voltage, causing the first auxiliary switch 12 and the second auxiliary switch 13 to operate based on changes in their first terminal voltages. In this case, the first auxiliary switch 12 and the second auxiliary switch 13 may be controllable switches. The specific types of the control module 11, the first auxiliary switch 12, and the second auxiliary switch 13 are not limited herein.

[0047] Figure 2 In the embodiment, the second end of the forward switch circuit 2 is connected to the first end of the phase sequence switching circuit 4; the second end of the reverse switch circuit 3 is connected to the second end of the phase sequence switching circuit 4.

[0048] Specifically, Figure 2 In the embodiment, when the motor rotates forward, the working switch circuit 1 controls the circuit between the bus and the forward rotation switch circuit 2 to be connected, and the circuit between the bus and the reverse rotation switch circuit 3 to be disconnected based on the switching state of the switching device 6, and then the forward rotation switch circuit 2 is turned on; when the motor reverses, the working switch circuit 1 controls the circuit between the bus and the reverse rotation switch circuit 3 to be connected, and the circuit between the bus and the forward rotation switch circuit 2 to be disconnected, and then the reverse rotation switch circuit 3 is turned on.

[0049] Figure 2 In the figure, the phase sequence switching circuit 4 has a third end connected to the first end of the measuring and protection device 5, and a fourth end connected to the power supply voltage busbar. The power supply voltage busbar is a common collection line for the control power supply, signal power supply, protection power supply, etc. in the power supply busbar system. The phase sequence of the power busbar is consistent with the phase sequence of the power supply voltage busbar; the measuring and protection device 5 has a second end respectively connected to the measuring and protection ends of multiple motors, which is used to switch the working conditions based on the phase sequence of its first end, thereby measuring the working parameters of each motor and switching the protection parameters according to the direction of each motor.

[0050] Specifically, Figure 2 In the embodiment, the phase sequence switching circuit 4 switches the switch state according to the on / off state of the forward switch circuit 2 and the reverse switch circuit 3. The control method of the forward working condition and the reverse working condition of the measuring and protection device 5 is as follows:

[0051] (1) When the forward rotation switch circuit 2 is turned on, the forward rotation switch circuit 2 outputs a control signal to the phase sequence switching circuit 4, so that the phase sequence switching circuit 4 switches the switch state, so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is the same as the phase sequence of the power supply voltage busbar, and then the measuring and protection device 5 switches to the forward rotation condition to measure the working parameters of the forward rotating motor.

[0052] (2) When the reversing switch circuit 3 is turned on, the reversing switch circuit 3 outputs a control signal to the phase sequence switching circuit 4, so that the phase sequence switching circuit 4 switches the switch state, so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is opposite to the phase sequence of the power supply voltage busbar. Then, the measuring and protection device 5 switches to the reversing working condition to measure the working parameters of the reversed motor.

[0053] It should be noted that the motor voltage busbar is a common collection line for control power, signal power, protection power, and other components within the motor busbar system. The busbar voltage directly supplies power to each motor, forming the primary portion of the electrical system. The operating switch circuit, forward and reverse switch circuit, phase sequence switching circuit, and measurement and protection devices constitute the secondary portion of the electrical system.

[0054] It should be noted that the operator can manually change the phase sequence of the bus according to the required motor direction, or adjust the phase sequence of the bus through devices such as forward and reverse switches and phase converters. The specific phase change method is not limited here.

[0055] The motor forward and reverse switching circuit provided by the present invention has the following characteristics: when the switching device makes the phase sequence of the motor power bus and the power bus the same, all motors start to rotate forward, and the forward switch circuit inside the motor forward and reverse switching circuit works; when the switching device makes the phase sequence of the motor power bus and the power bus opposite, all motors start to reverse, and the reverse switch circuit inside the motor forward and reverse switching circuit works, so that the phase sequence switching circuit switches the phase sequence of the voltage and current inside the measurement and protection device according to the switching status of the forward switch circuit and the reverse switch circuit, so that the measurement and protection device switches to the forward rotation condition according to the positive phase sequence of the motor and measures the working parameters of the forward rotating motor, or switches to the reverse rotation condition according to the reverse phase sequence of the motor and measures the working parameters of the reversed motor. Only one set of motor forward and reverse switching circuit is required to realize the forward and reverse control of all motors and the corresponding measurement and working parameter switching, which greatly reduces the circuit cost and simplifies the structure of the overall motor control circuit.

[0056] In some optional embodiments, such as Figure 4 As shown, the measurement and protection device 5 includes a relay protection device 51 and a measuring meter 52. The relay protection device 51 has a first terminal connected to the third terminal of the forward switch circuit 2, a second terminal connected to the third terminal of the reverse switch circuit 3, a third terminal connected to the third terminal of the phase sequence switching circuit 4, and a fourth terminal connected to the first measurement and protection terminal of each motor.

[0057] Specifically, Figure 4 In the embodiment, the relay protection device 51 is used to promptly cut off the power supply to any motor when it fails, and to separate the motor from the circuit, so as to prevent the motor failure from causing further damage or affecting the normal operation of other equipment; or when the front-stage circuit of the motor power supply end fails, the relay protection device 51 can automatically, quickly and selectively cut off the power supply to the affected motor to prevent the motor from further damage.

[0058] Figure 4 In the figure, the measuring meter 52 has a first end connected to the fourth end of the reversing switch circuit 3, a second end connected to the third end of the phase sequence switching circuit 4, and a third end connected to the second measurement and protection end of a motor respectively. It is used to measure the operating parameters of each motor, which may include: speed, torque, operating frequency, operating voltage, operating current, etc.

[0059] Optionally, in this example, only the operating parameters of the motor measuring device are switched by a single contact through the reverse switch circuit. Those skilled in the art can connect the measuring meter to the forward switch circuit according to actual needs to achieve double contact switching.

[0060] In some optional embodiments, such as Figure 5 As shown, the forward switch circuit 2 includes: a first relay KA-1 and a second relay KA-2, wherein, Figures 5 to 7 All S9 in the diagram are first auxiliary switches. Figure 5 The first ends of the first relay KA-1 and the second relay KA-2 connected in parallel are connected in series with the first auxiliary switch, and the second ends of the parallel connection are connected to other control loops respectively.

[0061] Specifically, refer to Figure 4 、 Figures 6 and 7 The first relay KA-1 includes a plurality of first auxiliary contacts KA1, and the second relay KA-2 includes a plurality of second auxiliary contacts KA2. Figure 7In the circuit diagram, six first auxiliary contacts KA1 (connected in series in loops 17-19, 21-23, 25-27, 29-31, 33-35, and 37-39, respectively) are connected to the first terminal of the relay protection device 51. Two second auxiliary contacts KA2 (connected in series in loops 41-43 and 45-47, respectively) are connected to the first terminal of the phase sequence switching circuit 4. The remaining first auxiliary contacts KA1 and second auxiliary contacts KA2 serve as backup contacts.

[0062] Specifically, Figure 6 In the circuit 807, the first auxiliary contact KA1 and the second auxiliary contact KA2 are both normally closed contacts, which are used to indicate abnormal operation of the first auxiliary switch and send the indication signal to the monitoring system of the pump station to alert the on-duty personnel.

[0063] Figure 6 In the embodiment, when the motor needs to rotate forward, the switching device 6 switches the switch state so that the first auxiliary switch 12 in the secondary circuit is closed, thereby energizing the coils of the first relay KA-1 and the second relay KA-2. Therefore, their normally closed contacts should be disconnected. At this time, the circuit 807 is blocked and the monitoring system of the pump station does not send out an abnormal signal. When any one of the coil circuits of the first relay KA-1 and the second relay KA-2 is broken, the two relays should be energized but are not, causing the corresponding normally closed contacts to remain closed and not operate. At this time, the circuit 807 is connected, causing the monitoring system of the pump station to send out an abnormal switching circuit signal.

[0064] Specifically, refer to Figure 4 and Figure 7 When the motor needs to rotate forward, the switching device 6 switches the switch state so that after the working switch circuit 1 is turned on, the reverse switch circuit 3 is turned off, the first relay KA-1 and the second relay KA-2 are energized, so that all the first auxiliary contacts KA1 in the normally open state and the second auxiliary contacts KA2 in the normally open state are closed, so that the relay protection device 51 turns off the protection function related to the motor reversal and turns on the protection function related to the motor forward. After the phase sequence switching circuit 4 switches the switch state so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is the same as the phase sequence of the power supply voltage busbar, the measuring and protection device 5 switches to the forward rotation working condition.

[0065] Specifically, refer to Figure 4 and Figure 7When the motor needs to reverse, the switching device 6 switches the switch state so that after the working switch circuit 1 is turned on, the reversing switch circuit 3 is turned on, the first relay KA-1 and the second relay KA-2 are de-energized, so that all the first auxiliary contacts KA1 in the normally open state and the second auxiliary contacts KA2 in the normally open state are disconnected, so that the relay protection device 51 turns off the protection function related to the forward rotation of the motor and turns on the protection function related to the reverse rotation of the motor. After the phase sequence switching circuit 4 switches the switch state so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is opposite to the phase sequence of the power supply voltage busbar, the measuring and protection device 5 switches to the reverse working condition.

[0066] It should be noted that, in this embodiment, the number of the first relay auxiliary contacts KA1 and the second relay auxiliary contacts KA2 is set based on six motors, and the specific number is not limited here.

[0067] In some optional embodiments, such as Figure 8 As shown, the reversing switch circuit 3 includes: a third relay KA-3, a fourth relay KA-4 and a fifth relay KA-5, wherein, Figures 8 to 10 All S9 in the diagram are second auxiliary switches. Figure 8 The first ends of the third relay KA-3, the fourth relay KA-4 and the fifth relay KA-5 connected in parallel are connected in series with the second auxiliary switch, and the second ends of the parallel connection are connected to other control loops respectively.

[0068] Specifically, refer to Figure 4 、 Figures 9 and 10 The third relay KA-3 includes a plurality of third auxiliary contacts KA3, the fourth relay KA-4 includes a plurality of fourth auxiliary contacts KA4, and the fifth relay KA-5 includes a plurality of fifth auxiliary contacts KA5. Figure 10 In the circuit diagram, the six third auxiliary contacts KA3 (connected in series in circuits 18-20, 22-24, 26-28, 30-32, 34-36, and 38-40, respectively) are connected to the second terminal of the relay protection device 51. The six fourth auxiliary contacts KA4 (connected in series in circuits 42-44, 46-48, 50-52, 54-56, 58-60, and 62-64, respectively) are connected to the first terminal of the meter 52. The two fifth auxiliary contacts KA5 (connected in series in circuits 74-76 and 78-80, respectively) are connected to the second terminal of the phase sequence switching circuit 4. The remaining third auxiliary contacts KA3, fourth auxiliary contacts KA4, and fifth auxiliary contacts KA5 serve as standby contacts.

[0069] Specifically, Figure 9In circuit 907, the third auxiliary contact KA3, the fourth auxiliary contact KA4, and the fifth auxiliary contact KA5 are all normally closed contacts. They are used to indicate abnormal operation of the phase sequence switching circuit 4 and are sent to the pump station's monitoring system to alert the on-duty personnel. When the motor needs to reverse, the switching device 6 switches the switch state so that the second auxiliary switch 13 in the secondary circuit is closed, thereby energizing the coils of the third relay KA-3, the fourth relay KA-4, and the fifth relay KA-5. Therefore, their normally closed contacts should all be open. At this time, circuit 907 is blocked and the pump station's monitoring system does not issue an abnormality signal. However, if any of the coil circuits of the third relay KA-3, the fourth relay KA-4, and the fifth relay KA-5 are disconnected, the three relays that should be energized are not, causing the corresponding normally closed contacts to remain closed and not operate. At this time, circuit 907 is connected, causing the pump station's monitoring system to issue a switching circuit abnormality signal.

[0070] Specifically, refer to Figure 4 and Figure 10 When the motor needs to rotate forward, the switching device 6 switches the switch state so that after the working switch circuit 1 is turned on, the forward switch circuit 2 is turned on, and the third relay KA-3, the fourth relay KA-4 and the fifth relay KA-5 are de-energized, so that the third auxiliary contact KA3, the fourth auxiliary contact KA4 and the fifth auxiliary contact KA5 in the normally open state are disconnected, so that the measuring meter 52 does not need to switch the current phase sequence and maintains positive sequence operation. The relay protection device 51 turns on the protection function related to the forward rotation of the motor and turns off the protection function related to the reverse rotation of the motor. After the phase sequence switching circuit 4 switches the switch state so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is the same as the phase sequence of the power supply voltage busbar, the measuring and protection device 5 switches to the forward rotation working condition.

[0071] Specifically, refer to Figure 4 and Figure 10 When the motor needs to reverse, the switching device 6 switches the switch state so that after the working switch circuit 1 is turned on, the forward switch circuit 2 is turned off, and the third relay KA-3, the fourth relay KA-4 and the fifth relay KA-5 are energized, so that the third auxiliary contact KA3, the fourth auxiliary contact KA4 and the fifth auxiliary contact KA5 in the normally open state are closed, so that the measuring meter 52 switches the current phase sequence and starts working according to the negative sequence. The relay protection device 51 turns off the protection function related to the forward rotation of the motor and turns on the protection function related to the reverse rotation of the motor. After the phase sequence switching circuit 4 switches the switch state so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is opposite to the phase sequence of the power supply voltage busbar, the measuring and protection device 5 switches to the reverse working condition.

[0072] It should be noted that, in this embodiment, the number of the third auxiliary contact KA3 , the fourth auxiliary contact KA4 and the fifth auxiliary contact KA5 is set based on six motors, and the specific number is not limited here.

[0073] In some optional embodiments, such as Figure 11 As shown, the phase sequence switching circuit 4 includes: a first switch KA2.1, a second switch KA2.2, a third switch KA5.1 and a fourth switch KA5.2. Figure 4 The first switch KA2.1 has a control end connected to the second end of the forward switch circuit 2, a first end connected to the A phase (i.e., YMa) of the power supply voltage busbar, and a second end connected to the A phase (i.e., 1YMa) of the electrical secondary motor voltage busbar on the top of the switch cabinet; the second switch KA2.2 has a control end connected to the second end of the forward switch circuit 2, a first end connected to the C phase (i.e., YMc) of the power supply voltage busbar, and a second end connected to the C phase (i.e., 1YMc) of the electrical secondary motor voltage busbar on the top of the switch cabinet; the third switch KA 5.1, its control end is connected to the second end of the reversing switch circuit 3, its first end is connected to the A phase of the power supply voltage busbar, and its second end is connected to the C phase of the motor voltage busbar; the fourth switch KA5.2, its control end is connected to the second end of the reversing switch circuit 3, its first end is connected to the C phase of the power supply voltage busbar, and its second end is connected to the A phase of the electrical secondary motor voltage busbar on the top of the switch cabinet; the B phase of the power supply voltage busbar (i.e., YMb) is directly connected to the B phase of the electrical secondary motor voltage busbar (i.e., 1YMb) on the top of the switch cabinet.

[0074] Specifically, refer to Figure 5 and Figure 11 The first switch KA2.1 and the second switch KA2.2 are both auxiliary contacts of the second relay KA-2. When the motor rotates forward, the working switch circuit 1 controls the second relay KA-2 to be energized, so that the first switch KA2.1 and the second switch KA2.2 are closed at the same time, connecting the A phase of the power supply voltage busbar with the A phase of the electrical secondary motor voltage busbar on the top of the switch cabinet, and connecting the C phase of the power supply voltage busbar with the C phase of the electrical secondary motor voltage busbar on the top of the switch cabinet. The B phase of the power supply voltage busbar and the B phase of the electrical secondary motor voltage busbar on the top of the switch cabinet are always kept in a connected state, so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is consistent with the phase sequence of the power supply voltage busbar voltage, and the measuring and protection device 5 switches to the forward rotation condition.

[0075] Specifically, refer to Figure 8 and Figure 11The third switch KA5.1 and the fourth switch KA5.2 are both auxiliary contacts of the fifth relay KA-5. When the motor reverses, the working switch circuit 1 controls the fifth relay KA-5 to be energized, so that the third switch KA5.1 and the fourth switch KA5.2 are closed at the same time, connecting the A phase of the power supply voltage busbar with the C phase of the electrical secondary motor voltage busbar on the top of the switch cabinet, and connecting the C phase of the power supply voltage busbar with the A phase of the electrical secondary motor voltage busbar on the top of the switch cabinet. The B phase of the power supply voltage busbar and the B phase of the electrical secondary motor voltage busbar on the top of the switch cabinet are always kept in a connected state, so that the phase sequence of the motor voltage busbar at the first end of the measuring and protection device 5 is opposite to the phase sequence of the power supply voltage busbar voltage, and the measuring and protection device 5 switches to the reverse working condition.

[0076] Specifically, Figure 12 and Figure 13 This is a specific circuit diagram for the relay protection device and meter. Since the electrical secondary current circuit cannot be open, each auxiliary contact is connected to the corresponding meter and relay protection device's switching input circuit for each motor switchgear. The manufacturer's customized program logic is implemented within the device to achieve current circuit switching under different operating conditions. Each motor switchgear's meter and relay protection device must be connected to an auxiliary contact. Due to the limitations of the backup switching input contacts for different devices, the motor meter (i.e., PM device) is only connected to the fourth auxiliary contact, KA4, and the relay protection device (i.e., K101 device) is connected to the first auxiliary contact, KA1, and the third auxiliary contact, KA3.

[0077] This embodiment provides a motor control system, such as Figure 14 As shown, it includes: a forward isolation trolley 7, a reverse isolation trolley 8 and the motor forward and reverse switching circuit of the above embodiments and any optional implementation methods thereof, wherein the forward isolation trolley 7 and the reverse isolation trolley 8 are arranged in the switching device; the forward isolation trolley 7, whose input end is connected to the power bus, and its first output end is connected to the first end of the working switch circuit 1 and the first output end of the reverse isolation trolley 8, and its second output end is connected to the second output end of the reverse isolation trolley 8 through the motor power bus and the power supply end of multiple motors (#1~#n), which is used to directly input the power bus voltage to each motor; the reverse isolation trolley 8, whose input end is connected to the power bus, is used to reverse the phase sequence of the power bus voltage and input it to each motor.

[0078] Specifically, Figure 14In the figure, the A-phase input terminal, B-phase input terminal and C-phase input terminal of the forward isolation trolley 7 are connected to the A-phase output terminal, B-phase output terminal and C-phase output terminal of the same through a metal busbar; the A-phase input terminal, B-phase input terminal and C-phase input terminal of the reverse isolation trolley 8 are connected to the C-phase output terminal, B-phase output terminal and A-phase output terminal of the same through a metal busbar. This is the phase sequence switching of the primary part of the electrical system.

[0079] Specifically, Figure 15 For the specific circuit diagram of the motor control system, refer to Figure 14 When the motor needs to rotate forward, the operator pushes the forward isolation trolley 7 into Figure 15 The position of the middle isolation trolley makes the phase sequence of the motor power bus the same as the phase sequence of the power bus. After the power supply ends of all motors are connected to the power bus through the forward isolation trolley 7, all motors rotate forward, the working switch circuit 1 is turned on, the forward switch circuit 2 is turned on, and the reverse switch circuit 3 is turned off. The phase sequence switching circuit 4 switches the switch state, so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device 5 is the same as the phase sequence of the power voltage bus. After that, the measuring and protection device 5 switches to the forward working condition, and the forward working parameters of all motors are measured.

[0080] Specifically, refer to Figure 14 and Figure 15 When the motor needs to be reversed, the operator pushes the reverse isolation trolley 8 into Figure 15 The position of the middle isolation trolley makes the phase sequence of the motor power bus opposite to the phase sequence of the power bus. After the power supply ends of all motors are connected to the power bus through the forward isolation trolley 7, all motors reverse, the working switch circuit 1 is turned on, the reverse switch circuit 3 is turned on, and the forward switch circuit 2 is turned off. The phase sequence switching circuit 4 switches the switch state, so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device 5 is opposite to the phase sequence of the power voltage bus. After that, the measuring and protection device 5 switches to the reverse working condition to measure the reverse working parameters of all motors.

[0081] It should be noted that after the operator pushes the forward isolation trolley 7 or the reverse isolation trolley 8 into the motor control system, the working principle of the motor control system is consistent with the principle described in the above embodiment and any optional implementation manner thereof, and will not be repeated here.

[0082] Optionally, the motor control system also includes: a monitoring system, whose input end is connected to the third end of the forward switch circuit and the third end of the reverse switch circuit respectively, and is used to alarm when the forward switch circuit and / or the reverse switch circuit fails, promptly reminding the operator to perform troubleshooting, thereby improving the reliability of the control system.

[0083] The motor control system provided by this embodiment has the following characteristics: when a forward isolation trolley is connected to the motor control system, the forward switch circuit is turned on and the reverse switch circuit is turned off; when a reverse isolation trolley is connected to the motor control system, the reverse switch circuit is turned on and the forward switch circuit is turned off. Therefore, the operator only needs to change the type of isolation trolley connected to the motor control system, and the motor control system can automatically switch the on-off state of each internal circuit, thereby controlling the forward or reverse rotation of the motor.

[0084] Although the embodiments of the present invention have been described with reference to 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. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A motor forward and reverse switching circuit, characterized in that: include: Switching device, working switch circuit, forward switch circuit, reverse switch circuit, phase sequence switching circuit and measurement protection device, wherein, a switching device, a first end of which is connected to the power bus, a second end of which is connected to the power supply terminal of each motor through the motor power bus, and a third end of which is connected to the first end of the working switch circuit; a working switch circuit, a second end of which is connected to the first end of the forward switch circuit, and a third end of which is connected to the first end of the reverse switch circuit; a forward rotation switch circuit, a second end of which is connected to the first end of the phase sequence switching circuit; a reversing switch circuit, a second end of which is connected to the second end of the phase sequence switching circuit; a phase sequence switching circuit, a third end of which is connected to the first end of the measurement and protection device, and a fourth end of which is connected to the power supply voltage busbar; A measuring and protection device, the second end of which is connected to the measuring and protection ends of the plurality of motors, and is used to switch the operating conditions based on the phase sequence of the first end, thereby switching the internal current measurement phase sequence and switching the protection parameters according to the direction of rotation of each motor; When the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward. At the same time, the working switch circuit is turned on based on the switch state of the switching device, so that the forward switch circuit is turned on and the reverse switch circuit is turned off. After the phase sequence switching circuit switches the switch state so that the phase sequence of the motor voltage small bus at the first end of the measuring and protection device is the same as the phase sequence of the power voltage small bus, the measuring and protection device switches to the forward rotation working condition; When the motor needs to be reversed, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor is reversed. Thereafter, the working switch circuit is turned on based on the switch state of the switching device, so that the reverse switch circuit is turned on and the forward switch circuit is turned off. After that, the phase sequence switching circuit switches the switch state so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is opposite to the phase sequence of the power voltage bus, the measuring and protection device is switched to the reverse working condition. The phase sequence of the power bus is consistent with the phase sequence of the power voltage small bus.

2. The motor forward and reverse switching circuit according to claim 1, characterized in that: The working switch circuit includes: a control module, a first auxiliary switch and a second auxiliary switch, wherein: a control module, a first end of which is connected to the third end of the switching device, and a second end and a third end of which are connected to the first end of the first auxiliary switch and the first end of the second auxiliary switch, respectively; The second end of the first auxiliary switch is connected to the first end of the forward switch circuit; The second end of the second auxiliary switch is connected to the first end of the reversing switch circuit; When the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward. At the same time, the control module controls the first auxiliary switch to be closed and the second auxiliary switch to be opened based on the switch state of the switching device, so that the forward switch circuit is turned on and the reverse switch circuit is turned off. When the motor needs to reverse, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses. At the same time, the control module controls the second auxiliary switch to be closed and the first auxiliary switch to be disconnected based on the switch state of the switching device, so that the reverse switch circuit is turned on and the forward switch circuit is turned off.

3. The motor forward and reverse switching circuit according to claim 1, characterized in that: The phase sequence switching circuit includes: a first switch, a second switch, a third switch and a fourth switch, wherein: a first switch, whose control end is connected to the second end of the forward switch circuit, whose first end is connected to the A phase of the power supply voltage busbar, and whose second end is connected to the A phase of the motor voltage busbar of the first end of the measurement and protection device; a second switch, a control end of which is connected to the second end of the forward switch circuit, a first end of which is connected to the C phase of the power supply voltage busbar, and a second end of which is connected to the C phase of the motor voltage busbar of the first end of the measurement and protection device; a third switch, whose control end is connected to the second end of the reversing switch circuit, whose first end is connected to the A phase of the power supply voltage busbar, and whose second end is connected to the C phase of the motor voltage busbar of the first end of the measurement and protection device; a fourth switch, whose control end is connected to the second end of the reversing switch circuit, whose first end is connected to the C phase of the power supply voltage busbar, and whose second end is connected to the A phase of the motor voltage busbar of the first end of the measurement and protection device; Phase B of the power supply voltage busbar is directly connected to phase B of the motor voltage busbar at the first end of the measurement and protection device; When the motor needs to rotate forward, the working switch circuit is turned on, the forward switch circuit is turned on, and the reverse switch circuit is turned off, so that the first switch and the second switch are turned on, and the third switch and the fourth switch are turned off; When the motor needs to reverse, the working switch circuit is turned on, the reverse switch circuit is turned on, and the forward switch circuit is turned off, so that the third switch and the fourth switch are turned on, and the first switch and the second switch are turned off.

4. The motor forward and reverse switching circuit according to claim 1, characterized in that: The measuring and protection device comprises: a relay protection device, wherein a first end of the relay protection device is connected to the third end of the forward switch circuit, a second end of the relay protection device is connected to the third end of the reverse switch circuit, a third end of the relay protection device is connected to the third end of the phase sequence switching circuit, and a fourth end of the relay protection device is connected to the first measurement terminal and the protection terminal of a motor respectively; When any motor fails, and / or the forward switch circuit fails, and / or the reverse switch circuit fails, the relay protection device cuts off the power supply to the corresponding motor based on the fault signal.

5. The motor forward and reverse switching circuit according to claim 4, characterized in that: The measuring and protection device also includes: A measuring meter, a first end of which is connected to the fourth end of the reversing switch circuit, a second end of which is connected to the third end of the phase sequence switching circuit, and a third end of which is respectively connected to the second measurement and protection end of a motor, and is used to measure the operating parameters of each motor.

6. The motor forward and reverse switching circuit according to claim 4, characterized in that: The forward switch circuit includes: a first relay and a second relay, wherein: a first relay, a first end of which is connected to the second end of the working switch circuit and the first end of the second relay, and a second end of which is connected to the first end of the relay protection device; a second relay, a second end of which is connected to the first end of the phase sequence switching circuit; When the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward. At the same time, the first relay and the second relay are energized and the reverse switch circuit is turned off. When the motor needs to be reversed, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses. At the same time, the first relay and the second relay lose power and the reversing switch circuit is turned on.

7. The motor forward and reverse switching circuit according to claim 5, characterized in that: The reverse switch circuit includes: a third relay, a fourth relay and a fifth relay, wherein: a third relay, a first end of which is connected to the second end of the working switch circuit, the first ends of the fourth relay and the fifth relay, and a second end of which is connected to the second end of the relay protection device; a fourth relay, a second terminal of which is connected to the first terminal of the measuring meter; a fifth relay, a second end of which is connected to the second end of the phase sequence switching circuit; When the motor needs to rotate forward, the switching device switches the switch state so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward. At the same time, the forward rotation switch circuit is turned on, and the third relay, the fourth relay, and the fifth relay are de-energized. When the motor needs to be reversed, the switching device switches the switch state so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses. At the same time, the forward switch circuit is turned off, and the third relay, the fourth relay and the fifth relay are energized.

8. A motor control system, characterized in that: include: A forward isolation trolley, a reverse isolation trolley, and a motor forward and reverse switching circuit according to any one of claims 1 to 7, wherein: The forward isolation trolley and the reverse isolation trolley are arranged in the switching device; The forward isolation trolley has an input end connected to the power bus, a first output end connected to the first end of the working switch circuit and the first output end of the reverse isolation trolley, and a second output end connected to the second output end of the reverse isolation trolley through the motor power bus and the power supply end of multiple motors, which is used to directly input the power bus voltage to each motor; The reverse isolation trolley has its input end connected to the power bus and is used to reverse the phase sequence of the power bus voltage and input it to each motor; When the motor needs to rotate forward, the forward isolation trolley is connected to the system, so that the phase sequence of the motor power bus is the same as the phase sequence of the power bus, and then the motor rotates forward. At the same time, the working switch circuit is turned on, so that the forward switch circuit is turned on and the reverse switch circuit is turned off. The phase sequence switching circuit switches the switch state so that the phase sequence of the motor voltage small bus at the first end of the measuring and protection device is the same as the phase sequence of the power voltage small bus, and the measuring and protection device switches to the forward working condition; When the motor needs to reverse, the reverse isolation trolley is connected to the system, so that the phase sequence of the motor power bus is opposite to the phase sequence of the power bus, and then the motor reverses. At the same time, the working switch circuit is turned on, so that the reverse switch circuit is turned on and the forward switch circuit is turned off. The phase sequence switching circuit switches the switch state, so that the phase sequence of the motor voltage bus at the first end of the measuring and protection device is opposite to the phase sequence of the power voltage bus, and the measuring and protection device switches to the reverse working condition.

9. The motor control system according to claim 8, characterized in that: The A-phase input terminal, the B-phase input terminal and the C-phase input terminal of the reverse isolation trolley are respectively connected to the C-phase output terminal, the B-phase output terminal and the A-phase output terminal of the same through a metal busbar.

10. The motor control system according to claim 8, characterized in that: Also includes: The monitoring system has an input end connected to the fourth end of the forward switch circuit and the fifth end of the reverse switch circuit, and is used to alarm when the forward switch circuit and / or the reverse switch circuit fails.

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