CN111740642B

CN111740642B - Dual-motor control system and engineering equipment

Info

Publication number: CN111740642B
Application number: CN202010613383.5A
Authority: CN
Inventors: 辜玉良; 吴俊�; 杨振华
Original assignee: Sany Automobile Manufacturing Co Ltd
Current assignee: Sany Automobile Manufacturing Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2022-03-01
Anticipated expiration: 2040-06-30
Also published as: CN111740642A

Abstract

The invention provides a double-motor control system and engineering equipment, wherein the double-motor control system comprises a first motor and a second motor, and further comprises: the first motor is connected to the main loop through the phase lines; the first starting device is connected to the main loop through a plurality of phase lines and is connected with the first motor in series; the detection device is used for detecting the current or the voltage on the main loop; the controller is respectively connected with the detection device and the first starting device, wherein at least two phase lines of the plurality of phase lines connected with the input end of the first starting device and the plurality of phase lines connected with the output end of the first starting device are respectively connected with the detection device, and the two phase lines connected with the detection device are out of phase; or the detection device is built in the first starting device. By the technical scheme of the invention, the stability and the reliability of the starting and the running of the dual-motor control system are effectively improved, and the damage of the motor is reduced.

Description

Dual-motor control system and engineering equipment

Technical Field

The invention relates to the technical field of engineering equipment, in particular to a double-motor control system and engineering equipment.

Background

The single motor of the crusher matched with the sand making line has larger power, generally more than 250 kilowatts, and is a double-motor asynchronous action, namely no-load starting, and after one motor is normally started, the other motor is started.

According to the characteristics of the industry, a combined action mode of starting a soft starter and a contactor is often adopted: the soft starter realizes the smooth start of a first motor with high power and the direct start of a second motor. In the aspect of safety design, the first motor and the second motor are both provided with current detection and display functions, and meanwhile, abnormal states are monitored.

However, the prior art has the following problems:

1) the second motor generally only depends on the circuit breaker protection, and the mode is single, probably causes accidents such as motor damage after the abnormity such as overload, motor desynchrony appear.

2) After the soft starter starts the motor, the soft starter is switched to a bypass (a built-in contactor) to operate, and the risk is the same as that of the first soft starter. Meanwhile, a monitoring mechanism is not established for abnormal parameters such as phase loss, overload and the like in the starting process of the first motor.

3) The single-phase current can be detected by the parameters of the first motor in operation, and other phase abnormalities such as phase loss, three-phase imbalance and the like can not be timely judged, so that obvious fault risks exist.

Disclosure of Invention

Embodiments according to the present invention are directed to improving at least one of the technical problems of the related art or the related art.

In view of the above, an object according to an embodiment of the present invention is to provide a dual motor control system.

Another object according to an embodiment of the present invention is to provide an engineering apparatus.

To achieve the above object, an embodiment according to a first aspect of the present invention provides a main circuit having a plurality of phase lines, through which a first motor is connected to the main circuit; the first starting device is connected to the main loop through a plurality of phase lines, is connected with the first motor in series and is used for starting the first motor; the detection device is used for detecting the current or the voltage on the main loop; the controller is connected with the detection device and the first starting device respectively and used for controlling the starting and stopping of the first starting device according to the detection result of the detection device; among a plurality of phase lines connected with the input end of the first starting device and a plurality of phase lines connected with the output end of the first starting device, at least two phase lines are respectively connected with a detection device, and the two phase lines connected with the detection devices are out-of-phase; or the detection device is built in the first starting device.

In the technical scheme, the detection devices are respectively connected to at least two phase lines of different phases, and the voltage or the current is detected, so that whether abnormal phenomena such as phase failure, overload and the like exist on a loop can be judged by combining a certain algorithm from the current or the voltage value on each phase line, namely, the starting condition of the first motor is monitored in the starting process of the first motor, the first motor can be started stably, the abnormal conditions can be found in time, the abnormal conditions can be timely treated, and the accidents that the first motor is abnormal and cannot be timely treated and the motor is damaged are reduced.

The first starting device is connected with the first motor in series, so that the first starting device can directly start the first motor conveniently; the detection device is used for detecting the current or the voltage on the main loop, the detected data is direct and reliable, the detection device is easy to select types, and for example, a current transformer, a voltage transformer or a voltmeter, an ammeter, a transmitter and the like can be selected; at least two phase lines are respectively connected with a detection device, and the two phase lines connected with the detection device are out of phase, namely, at least two phases of current or voltage on a main loop can be detected, so that whether the input end or the output end of the first starting device has abnormal conditions such as phase failure or overload or the like can be conveniently determined, timely processing is carried out, and the phenomena of failure, damage and the like of the first motor due to overload or phase failure are reduced; the detection device can be built in the first starting device, so that the detection and calculation functions of the first starting device can be fully exerted, the components are reduced, and the circuit structure is simplified.

It can be understood that the parameters such as current, voltage and the like detected by the detection device can be directly displayed on the detection device or transmitted to the controller, and whether a fault occurs is judged after the controller performs comprehensive operation.

In the above technical solution, the plurality of phase lines include a first phase line, a second phase line and a third phase line; the input end of the first starting device is connected with a plurality of phase lines, and the first phase line is connected with a detection device; and the second phase line or the third phase line is connected with a detection device.

In the technical scheme, a first phase line connected with the input end of a first starting device is connected with a detection device, a second phase line or a third phase line connected with the output end of the first starting device is connected with the detection device, so that the input end and the output end of the first starting device are both connected with the detection device, and no matter which end has the phenomena of phase loss, overload and the like, the detection device can be found in time, namely the detection device can be detected in the first time when an abnormal condition occurs, the reaction speed of equipment is improved, and the accident can be prevented in time; in addition, the first phase line of the input end is connected with a detection device, and the second phase line or the third phase line of the output end is connected with a detection device, namely a plurality of detection devices are connected to different phases at two ends of the first starting device, so that whether the two ends of the first starting device have a phase failure phenomenon or not is conveniently determined, and the monitoring of the operation conditions such as phase failure, whether each phase is balanced or not and the like is conveniently carried out in the operation process of the first motor.

More specifically, for example, the detection of phase loss can be performed as follows: the detection device is arranged in the soft starter, the thyristors in the soft starter are connected in parallel with a 3-phase circuit, the voltage applied between the thyristors in operation can be respectively detected, after the soft starter is normally started, the three-phase circuit is sequentially checked, namely the three phase lines are sequentially checked, and whether the phase is in short phase or not is judged according to the change condition of the three-phase voltage. The external detection device, for example, the detection device adopts a current transformer, and whether the load is normally started or not is determined through the detection of the current.

In any one of the above technical solutions, the first starting device is a soft starter, a frequency converter, or a contactor.

In the technical scheme, according to the specific use scene of the equipment, the first starting device can flexibly select a soft starter or a frequency converter or a contactor, and the above devices can start the first motor.

In the above technical solution, the dual-motor control system further includes: a power source; one end of the intermediate relay is connected with the power supply, the other end of the intermediate relay is connected with the soft starter, and the intermediate relay is used for outputting a control signal; the power supply is also connected with the input end of the soft starter and is used for supplying power to the intermediate relay and the soft starter.

In this technical scheme, be soft starter through setting up independent power, the auxiliary relay power supply, the required electric energy of soft starter and auxiliary relay comes from independent power promptly, and not get from the electric wire netting, therefore when first motor starts, can avoid the electric wire netting, also be the heavy current in the major loop to soft starter, auxiliary relay's impact, promote soft starter, the stability and the reliability that auxiliary relay used, can also ensure the accuracy of the control signal that auxiliary relay exported, avoid control signal the distortion to appear and lead to the phenomenon that the error appears in the testing result judgement.

In the above technical solution, the dual-motor control system further includes: the first starting device is connected with the main loop through the first circuit breaker; and/or the first contactor is arranged in parallel with the soft starter, or the first contactor is built in the soft starter.

In the technical scheme, the first circuit breaker is arranged, so that the first motor can be protected, and when faults such as phase loss, overload and the like occur, a circuit is timely disconnected, and the first motor is prevented from being damaged; the arrangement of the first contactor is connected with the soft starter in parallel or is internally arranged in the soft starter, after the soft starter successfully starts the first motor, the circuit is switched to the first contactor, namely the first contactor is used as a bypass, after the first motor is successfully started by the soft starter, the connection between the soft starter and the main loop is disconnected, the first contactor replaces the soft starter to connect the main loop and the first motor, so that the soft starter is protected, the impact of factors such as large current in a main loop power grid and the like on electronic devices in the soft starter is avoided, the possibility of damage of the electronic devices in the soft starter is reduced, and the service life of the soft starter is prolonged.

In the above technical solution, the first circuit breaker may be a molded case circuit breaker, an earth leakage circuit breaker, a small circuit breaker, a surge protector, an ac contactor, an isolating switch, or a motor protection type circuit breaker.

In any one of the above technical solutions, the dual-motor control system further includes: the second contactor is connected to the main loop through a plurality of phase lines; the second motor is connected with the main loop through a second contactor and a plurality of phase lines, and the second contactor is used for starting the second motor.

In the technical scheme, the second motor is started by arranging the second contactor, so that the motor is simple in structure, easy to control and low in cost.

In the above technical solution, the dual-motor control system further includes: the second contactor is connected with the main loop through the second circuit breaker; and the second motor is connected with the second contactor through the thermal relay.

In this technical scheme, through setting up second circuit breaker and thermorelay, can protect the second motor, at the start-up in-process, perhaps in the operation process, when default phase, unbalanced three phase appear, can stop the operation of second motor immediately through thermorelay, reaction rate is fast, is favorable to reducing the phenomenon emergence that the second motor damaged, and simple structure, low cost.

In the above technical solution, among a plurality of phase lines between the second circuit breaker and the second contactor, at least two phase lines are respectively connected with a detection device, and the detection devices are further connected with the controller.

In the technical scheme, the detection devices are respectively connected to the at least two phase lines, so that currents or voltages on two phases can be detected, the detection devices are connected with the controller, data detected by the detection devices between the second circuit breaker and the second contactor can be transmitted to the controller, the controller can calculate whether the loop has the phenomena of phase loss, three-phase imbalance and the like according to the currents or voltages of the two phases, and the judgment mode is simple and reliable.

In any one of the above technical solutions, the controller is further connected to the second contactor, and the controller is configured to control opening and closing of the second contactor according to a detection result of the detection device.

In the technical scheme, the controller is connected with the second contactor, so that the controller can automatically control the opening and closing of the second contactor according to a detection result, the starting or running of the second motor is stopped without manual operation of a user, and the second motor is prevented from being damaged.

Furthermore, each detection device is connected through the controller, so that the operation parameters of the first motor and the second motor can be acquired, compared and analyzed by the controller, and whether the operation of the first motor and the operation of the second motor are synchronous or not is judged, namely, the synchronous condition of the operation of the first motor and the operation of the second motor are monitored, and abnormity is discovered in time, the reduction of the integral loading capacity of equipment is avoided, the motor is damaged, or the loss of energy consumption, materials and the like caused by sudden shutdown is avoided, and the loss caused by stopping production, maintenance inspection or replacement is reduced.

An embodiment according to a second aspect of the present invention provides an engineering apparatus, comprising: an apparatus body; the dual-motor control system according to any one of the above first aspects is provided on the device body.

In this technical scheme, by adopting the dual-motor control system according to any one of the above technical schemes, all beneficial effects of the above technical scheme are achieved, and are not described herein again.

The engineering equipment is a crusher, a coal conveyor, a stacker, a coal cutter or a crane.

Additional aspects and advantages of embodiments in accordance with the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments in accordance with the invention.

Drawings

FIG. 1 is an electrical schematic diagram of a dual motor control system according to one embodiment provided by the present invention;

FIG. 2 is a block diagram illustrating the structure of a dual motor control system in accordance with one embodiment of the present invention;

FIG. 3 is a block diagram schematically illustrating the construction of an engineering device according to an embodiment of the present invention;

FIG. 4 is a block diagram illustrating the structure of a dual motor control system in accordance with one embodiment of the present invention;

FIG. 5 is a block diagram of a control loop of a dual motor control system in accordance with one embodiment provided by the present invention;

FIG. 6 is a schematic control flow diagram illustrating the operation of a dual motor control system in accordance with one embodiment of the present invention;

FIG. 7 is a schematic view of a work flow of a dual-motor control system for alarming in reverse phase sequence according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a working flow of a dual-motor control system for phase loss phase discrimination according to an embodiment of the present invention;

fig. 9 is a schematic workflow diagram of a dual-motor control system for bypass phase fault discrimination according to an embodiment of the present invention.

Wherein, the correspondence between the reference numbers and the part names in fig. 1 to 4 is:

the system comprises a 1 dual-motor control system, a 10 main loop, a 100 first phase line, a 102 second phase line, a 104 third phase line, a 12 first motor, a 120 first starting device, a 122 first circuit breaker, a 124 first contactor, a 126 power supply, a 128 intermediate relay, a 14 second motor, a 140 second circuit breaker, a 142 second contactor, a 144 thermal relay, a 16 detection device, a 160 current transformer, a 162 transmitter, an 18 controller, a 191 first region, a 192 second region, a 193 third region, a 194 fourth region, 2 engineering equipment, 20 equipment bodies, 30 acquisition units and 34 display units.

Detailed Description

In order that the above objects, features and advantages of embodiments in accordance with the present invention may be more clearly understood, embodiments in accordance with the present invention are described in further detail below with reference to the accompanying drawings and the detailed description. It should be noted that features of embodiments according to the invention may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments according to the invention, however, embodiments according to the invention may be practiced in other ways than those described herein, and therefore, embodiments according to the invention are not limited in scope by the specific embodiments disclosed below.

Some embodiments provided according to the present invention are described below with reference to fig. 1 to 9.

As shown in fig. 1, according to an embodiment of the first aspect of the present invention, a dual-motor control system 1 is provided, the dual-motor control system 1 includes a first motor 12, a second motor 14, a main loop 10, a first starting device 120, a detecting device 16, and a controller 18, wherein the first starting device 120 is a soft starter.

Specifically, the main circuit 10 has a plurality of phase lines, and the first motor 12 is connected to the main circuit 10 through the plurality of phase lines. The soft starter is also connected to the main circuit 10 by a plurality of phase lines. The soft starter is connected with the first motor 12 in series and is used for starting the first motor 12; the controller 18 is connected to the detection device 16 and the first activation device 120, respectively, and is configured to control the on/off of the first activation device 120 according to a detection result of the detection device 16.

Sensing device 16 includes a current transformer 160 and a transducer 162. The detecting device 16 is used for detecting the current on the main circuit 10, wherein, of the plurality of phase lines connected to the input end of the soft starter and the plurality of phase lines connected to the output end of the soft starter, at least two phase lines are respectively connected with the detecting device 16, and the two phase lines connected with the detecting device 16 are out of phase.

Specifically, the plurality of phase lines includes a first phase line 100, a second phase line 102, and a third phase line 104. A current transformer 160 is connected to the second phase line 102 connected to the input of the soft starter to detect the current on the second phase line 102 during the starting process and the running process of the first motor 12. A current transformer 160 and a transmitter 162 are connected to the third phase line 104 connected between the output of the soft starter and the first motor 12, i.e. between the soft starter and the first motor 12, to detect the current on the third phase line 104 during start-up and operation of the first motor 12.

In this embodiment, the detection device 16 is connected to the second phase line 102 and the third phase line 104, that is, the detection device 16 is connected to different phase lines and detects current, the detection device 16 is connected to the controller 18, and the controller 18 can determine whether there is an abnormal phenomenon such as a phase failure, an overload, and the like on the loop according to the current on each phase line and by combining a certain algorithm, so that the starting condition of the first motor 12 is monitored during the starting process of the first motor 12, which is beneficial to smooth starting of the first motor 12, and timely finding an abnormal condition and timely handling the abnormal condition, for example, automatically turning off the first starting device 120, thereby reducing the occurrence of an accident of the first motor 12, which cannot be handled in time and results in motor damage.

The sensing device 16 is not limited to the current transformer 160 and the transducer 162, but may be a voltage transformer or a voltmeter, an ammeter, or the like.

It can be understood that the parameters such as the detected current and voltage detected by the detection device 16 may be directly displayed on the detection device 16, or may be transmitted to the controller 18, and the controller 18 performs a comprehensive operation to determine whether there is a fault, and when there is a fault, the first starting device 120 is automatically turned off to stop the starting or running of the first motor 12, so as to avoid the accident that the first motor 12 is damaged.

In other embodiments, one detection device 16 is connected to each of the three phase lines to which the input of the soft starter is connected.

In further embodiments, the output of the soft starter is connected to a first phase line 100 and a second phase line 102, respectively, to which a detection device 16 is connected.

In other embodiments, the detection device 16 is built in the soft starter to fully exert the detection and calculation functions of the soft starter, reduce the number of components and simplify the circuit structure.

In some embodiments, the detection of phase loss may be performed as follows: the detection device 16 is built in the soft starter, the thyristors in the soft starter are connected in parallel with a three-phase circuit, the voltages applied between the thyristors in operation can be respectively detected, after the soft starter is started normally, the three-phase circuit is sequentially checked, namely the three phase lines are sequentially checked, and whether the phase is open is judged according to the change condition of the three-phase voltage. Whether the load is normally started or not can also be determined by an external detection device 16, for example, the detection device 16 adopts a current transformer 160 through the detection of the current.

It is understood that the first starting device 120 is not limited to a soft starter, but may be a frequency converter or a contactor, so that the specific type of the first starting device 120 is flexibly selected according to the specific use scenario of the apparatus.

In the above embodiment, the two-motor control system 1 further includes the power supply 126 and the intermediate relay 128.

One end of the intermediate relay 128 is connected to the power supply 126, the other end of the intermediate relay 128 is connected to the soft starter (i.e., the first starting device 120), and the intermediate relay 128 is configured to output a control signal; a power supply 126 is also connected to the input of the soft starter, the power supply 126 being used to power the intermediate relay 128 and the soft starter, so that the power required by the soft starter and the intermediate relay 128 comes from a separate power supply 126 rather than from the grid. When first motor 12 starts, can avoid the impact of the heavy current in the electric wire netting to soft starter, intermediate relay 128, promote the stability and the reliability that soft starter, intermediate relay 128 used, can also ensure the accuracy of the control signal that intermediate relay 128 output, avoid control signal to appear the distortion and lead to the phenomenon that the testing result judgement error appears.

In the above embodiment, the two-motor control system 1 further includes the first circuit breaker 122 and the first contactor 124. The first starting device 120 is connected to the main circuit 10 by means of a first circuit breaker 122; the first contactor 124 is connected in parallel with the soft starter, that is, the input end of the first contactor 124 is connected to the first circuit breaker 122, the output end of the first contactor 124 is connected to the first motor 12, and the detection device 16 is connected to the third phase line 104 between the output end of the first contactor 124 and the first motor 12.

In this embodiment, by providing the first circuit breaker 122, the first motor 12 can be protected, and when a fault such as a phase loss or an overload occurs, the circuit is timely disconnected, so that the first motor 12 is prevented from being damaged; the first contactor 124 is arranged and connected in parallel with the soft starter, so that after the soft starter successfully starts the first motor 12, the circuit can be switched to the first contactor 124, that is, the first contactor 124 serves as a bypass, after the first motor 12 is successfully started by the soft starter, the connection between the soft starter and the main loop 10 is disconnected, the first contactor 124 replaces the soft starter to connect the main loop 10 and the first motor 12, and therefore the soft starter is protected, the impact of factors such as large current in a power grid of the main loop 10 and the like on electronic devices in the soft starter is avoided, the possibility of damage of the electronic devices in the soft starter is reduced, and the service life of the soft starter is prolonged.

In other embodiments, the first contactor 124 is built into the soft starter.

In some embodiments, only the first circuit breaker 122 is provided, i.e. the softstarter is not provided with a bypass.

In the above embodiment, the first circuit breaker 122 is any one of a molded case circuit breaker, an earth leakage circuit breaker, a miniature circuit breaker, a surge protector, an ac contactor, a disconnector, and a motor protection type circuit breaker.

In any of the above embodiments, the dual-motor control system 1 further includes: a second contactor 142 connected to the main circuit 10 through a plurality of phase lines; the second motor 14 is connected to the main circuit 10 through the second contactor 142 and a plurality of phase lines, and the second contactor 142 is used for starting the second motor 14, and has a simple structure, easy operation and low cost.

In the above embodiment, the two-motor control system 1 further includes: a second circuit breaker 140, through which the second contactor 142 is connected to the main circuit 10; the thermal relay 144, the second motor 14 is connected to the second contactor 142 through the thermal relay 144.

In this embodiment, by providing the second circuit breaker 140 and the thermal relay 144, the second motor 14 can be protected, and in the starting process or the operating process, when the phase loss and the three-phase imbalance occur, the operation of the second motor 14 can be immediately stopped by the thermal relay 144, so that the reaction speed is high, the occurrence of the phenomenon of damage to the second motor 14 is reduced, and the structure is simple and the cost is low.

The second circuit breaker 140 may be any one of a molded case circuit breaker, an earth leakage circuit breaker, a miniature circuit breaker, a surge protector, an ac contactor, a disconnecting switch, and a motor protection type circuit breaker.

In the above embodiment, one detection device 16 is connected to each of the second phase line 102 and the third phase line 104 among the plurality of phase lines between the second circuit breaker 140 and the second contactor 142, so as to detect the current or voltage of the second phase and the third phase. The detection devices 16 connected to the second phase line 102 and the third phase line 104 are further connected to the controller 18, so that the controller 18 can calculate whether a loop in which the second motor 14 is located has a phase failure, a three-phase imbalance, and the like according to the currents or voltages on the second phase line 102 and the third phase line 104 detected by the detection devices 16, and the determination method is simple and reliable.

In any of the above embodiments, the controller 18 is also connected to the second contactor 142, as shown in fig. 2. The controller 18 is further configured to automatically control the on/off of the second contactor 142 according to the detection result of the detection device 16, and no manual operation is required by a user, that is, when the detection result of the detection device 16 is that the main circuit 10 has a phase failure, an undervoltage, an overload, and the like, the controller 18 may control the second contactor 142 to close, stop the start or operation of the second motor 14, and avoid the second motor 14 from being damaged.

Further, the controller 18 is connected with the detection device 16, so that the operation parameters of the first motor 12 and the second motor 14 can be obtained, compared and analyzed by the controller 18, thereby judging whether the operations of the first motor 12 and the second motor 14 are synchronous, namely, monitoring the synchronous operation conditions of the first motor 12 and the second motor 14, and finding out abnormality in time, thereby avoiding the reduction of the integral loading capacity of the equipment, causing the damage of the motors, or the loss of energy consumption, materials and the like caused by sudden shutdown, and reducing the loss caused by stopping production, maintenance inspection or replacement.

As shown in fig. 3, an embodiment according to a second aspect of the present invention provides an engineering apparatus 2 including: an apparatus body 20; the dual-motor control system 1 according to any one of the above-described first embodiments is provided on the device body 20.

In this embodiment, by using the dual-motor control system 1 of any one of the above embodiments, all the beneficial effects of the above embodiments are achieved, and are not described herein again.

The engineering equipment 2 is a crusher or a coal conveyor or a stacker or a coal cutter or a crane.

The equipment body 20 may be a machine shaft of a crusher, a conveyor belt of a coal conveyor, a body of a coal cutter, a frame of a crane, etc.

As shown in fig. 1, the dual-motor control system 1 according to one embodiment of the present invention generally has four regions, namely, a first region 191, a second region 192, a third region 193, and a fourth region 194, which are indicated by dashed boxes, wherein the first region 191 is used for abnormal/normal monitoring of the first motor 12 during a starting process, and current detection and operation fault detection of the first motor 12; the second region 192 is used for monitoring the state of the first motor 12 during operation, and also used for detecting the first motor 12 during starting, and monitoring phase loss, current, voltage, and the like; the third region 193 is used for monitoring the second motor 14, that is, for acquiring state monitoring during two-phase operation of the second motor 14, and for monitoring the operating current, voltage, phase failure, and the like of the second motor 14; the fourth region 194 is used for operation protection, overload protection, etc. of the second electric machine 14.

As shown in a first area 191 indicated by a dashed box in fig. 1, the first circuit breaker 122, the current transformer 160, and the power supply 126 are disposed in the first area 191. Specifically, the second phase of the three phases of the main circuit 10 is added with a current detection device, i.e. a current transformer 160, and the current transformer 160 can be directly displayed by an ammeter; or connected to the controller 18, and the current value is displayed in real time after being processed by the controller 18; the main contactor normally open auxiliary contacts are connected in series before the transmitter 162 is connected, so that the influence of the impact of the power supply 126 on the transmitter 162 is reduced.

The soft starter fault detection loop introduces an independent power supply 126, and reduces adverse factors of a power grid in starting and running.

As shown in the second area 192 in fig. 1, a current transformer 160 and a transmitter 162 are added to the third phase of the three phases at the output end of the soft starter, that is, the third phase 104, and are connected to the soft starter, and the start and operation states of the first motor 12 are calculated and judged by using a soft starter control algorithm, and then the states are transmitted to the controller 18; including phase loss, bypass, voltage, etc.

As shown in a third region 193 in fig. 1, a current transformer 160 and a transmitter 162 are respectively added to two phases, namely, a second phase and a third phase, of the three phases of the main circuit 10, so as to transmit monitoring signals to the controller 18, and the controller 18 calculates and judges the starting and operating states of the motor; including phase loss, bypass, voltage, etc.

As shown in the fourth region 194 of fig. 1, the primary circuit 10 increases thermal relay 144 protection.

Fig. 5 shows a block schematic of the control loop of the two-motor control system 1; as shown in fig. 5, the first motor 12 collects the state parameters of the soft starter during starting through the detection device 16, and feeds the state parameters back to the controller 18, for example, the real-time current during starting and running is fed back to the controller 18, and the controller 18 determines whether a phase fault occurs in the bypass, specifically, the phase of the phase fault occurs, and the like according to the real-time current feedback result. Similarly, the second motor 14 also detects the current value in the starting and running processes through the current transformer 160 connected with the second motor, so as to perform overload protection, phase failure alarm and the like, thereby reducing the occurrence of damage accidents of the second motor 14; meanwhile, the controller 18 determines whether the two motors run synchronously by performing summary analysis, comparison, transportation and the like on the detection results of the plurality of detection devices 16, and records related operation data, thereby reducing the occurrence of accidents caused by motor damage, and keeping operation records so that a user can inquire the operation records.

Fig. 4 is a block diagram showing a schematic structure of the two-motor control system 1 according to the embodiment.

As shown in fig. 4, the dual-motor control system 1 includes a collecting unit 30, a controller 18 and a display unit 34, wherein the collecting unit 30 is configured to collect operation parameters of the first motor 12, such as real-time current, real-time voltage, starting condition of the soft starter, and the like; the acquisition unit 30 is also used for acquiring the operation parameters of the second motor 14, such as real-time voltage, real-time current and the like; the controller 18 is configured to obtain the operation parameters collected by the collecting unit 30, and monitor the operation conditions of the first motor 12 and the second motor 14, such as fault monitoring, overload monitoring, phase loss monitoring, and phase sequence monitoring. The controller 18 is also configured to cooperatively manage the first motor 12 and the second motor 14 to ensure that the first motor 12 and the second motor 14 operate synchronously. The display unit 34 is used for displaying the monitored real-time current, voltage and other data, and the specific conditions of the operation state, such as whether the phase is open or not, whether the phase is overloaded or not.

Fig. 6 shows a control flow diagram of the dual-motor control system in fig. 4. As shown in fig. 6, the work control flow of the dual-motor control system is as follows:

step S10: acquiring an equipment operation instruction;

step S12: controlling the first motor and the second motor to operate according to the equipment operation instruction;

step S14: collecting operating parameters of a first motor and a second motor;

step S16: according to the operation parameters, fault monitoring and phase sequence monitoring are carried out on the first motor and the second motor, and the first motor and the second motor are subjected to cooperative processing;

step S18: and displaying the monitoring conditions of the real-time current and the running state of the first motor and the second motor.

Through carrying out above-mentioned work flow, after first motor, second motor start, monitor the operating parameter of first motor, second motor to according to the condition of monitoring, judge whether have phenomenons such as default phase, overload, still carry out coprocessing to first motor, second motor, be favorable to reducing the operation trouble of first motor, second motor, reduce the condition of two asynchronous operation of motor, promote the stability and the reliability of two motor control system work.

Furthermore, the running states of the first motor and the second motor are monitored in real time, the abnormality such as overload and phase failure is judged in time, and the system and motor state monitoring is realized through calculation, for example, the monitoring and judgment of the phase sequence state of a power grid in the starting and running processes can be realized through phase sequence calculation, and the monitoring and the judgment comprise 1) reverse phase sequence, 2) phase failure fault, 3) bypass fault and the like.

Fig. 7 shows a schematic workflow of a negative phase sequence alarm.

As shown in fig. 7, specifically, the workflow for the negative phase-sequence alarm is as follows:

step S100: acquiring a device starting instruction;

step S102: controlling the control loop to be electrified according to the equipment starting instruction;

step S104: after the control loop is electrified, controlling the main loop to be electrified;

step S106: after the main loop is electrified, judging whether reverse phase sequence faults exist during soft start;

step S108: if yes, disconnecting the power supplies of the control loop and the main loop, adjusting the incoming line phase sequence, and jumping to the step S102;

step S110: if not, the reverse phase sequence alarm detection is completed.

The reverse phase sequence alarm detection method is simple, easy to control and high in judgment speed.

Fig. 8 shows a schematic workflow of open-phase discrimination.

As shown in fig. 8, the working flow for the open-phase discrimination is as follows:

step S200: acquiring a device starting instruction;

step S202: controlling the control loop to be electrified according to the equipment starting instruction;

step S204: after the control loop is electrified, controlling the main loop to be electrified;

step S206: after the main loop is powered on, judging whether the first phase line is in a phase-lack state, if so, executing a step S208, and if not, executing a step S210;

step S208: eliminating the phase failure and executing step S202;

step S210: judging whether the second phase line is in phase failure, if so, executing step S208, and if not, executing step S212;

step S212: judging whether the third phase line is in phase failure, if so, executing step S208, and if not, executing step S214;

step S214: and judging the phase-missing fault and completing the discrimination.

Fig. 9 shows a schematic workflow of bypass phase fault discrimination.

As shown in fig. 9, the work flow of bypass phase fault discrimination is as follows:

step S300: acquiring a device starting instruction;

step S302: controlling the control loop to be electrified according to the equipment starting instruction;

step S304: after the control loop is electrified, controlling the main loop to be electrified;

step S306: after the main loop is electrified, soft start is carried out, and after the soft start is finished, the main loop is switched to a bypass;

step S308: after the bypass is switched, whether the first phase line is in a phase-missing state is judged, if so, step S310 is executed, and if not, step S312 is executed;

step S310: eliminating the phase failure and executing step S302;

step S312: judging whether the second phase line is in phase failure, if so, executing the step S310, and if not, executing the step S314;

step S314: judging whether the third phase line is in phase failure, if so, executing step S310, otherwise, executing step S316;

step S316: and judging the bypass phase fault and screening.

By executing the reverse phase sequence alarm detection, the open phase discrimination and the bypass phase discrimination, the condition of influencing the operation of the motor can be found in advance, the stability and the reliability of the starting and operating processes of the first motor and the second motor can be ensured, and the phenomenon of damage of the motor can be reduced.

Besides the work of alarm detection of the reverse phase sequence and the like, the controller can also realize data monitoring and recording of overvoltage, undervoltage, overload and the like.

The specific embodiment has the following advantages:

1) and the independent power supply reduces abnormal judgment of the detection loop caused by power grid impact.

2) The comprehensive monitoring of the first motor state is realized by fully utilizing the functions of the soft starter or a control algorithm, and comprises the following steps of: starting and operating current values and multiples; detecting bypass fault phase, discriminating, alarming and protecting, and indicating specific phase, detecting open-phase fault, discriminating, alarming and protecting, and indicating specific phase; and detecting the phase sequence and alarming.

3) And the control algorithm is adopted to realize the comprehensive monitoring of the second motor, and the monitoring comprises the following steps: starting and running process current values; overload protection, phase failure alarm, phase sequence detection and alarm.

4) The controller effectively ensures that the first motor and the second motor are stably started and the states in the running process are comprehensively monitored and controlled.

The first motor and the second motor are synchronously controlled, the best cost is achieved in operation, and the most full functions are achieved.

It can be understood that the frequency converter can be used for replacing the soft starter for starting the first motor and the second motor; the second motor can be started by adopting a star-triangle structure to replace a second contactor; the control algorithm of the first motor can be realized by a soft starter or a controller, and the communication mode and the protocol can be various; the second motor can collect three-phase current, is not limited to collecting two-phase current, and can also collect voltage in one phase and collect current in the other phase in a combined mode to realize the detection of phase loss and undervoltage.

In addition, the controller is not limited to determining whether the two motors are synchronous, and output function extension can be achieved, such as functions of data statistics and report forms, APP display and the like.

The embodiment provided by the invention is described in detail in combination with the attached drawings, and by the embodiment, the starting and running stability and reliability of the dual-motor control system are effectively improved, and the condition that the motor is damaged is reduced.

In embodiments according to the present invention, the terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless expressly limited otherwise. The terms "mounted," "connected," "fixed," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, a removable connection, or an integral connection; "coupled" may be direct or indirect through an intermediary. Specific meanings of the above terms in the embodiments according to the present invention can be understood by those of ordinary skill in the art according to specific situations.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example in accordance with the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above is only a preferred embodiment according to the present invention, and is not intended to limit the embodiment according to the present invention, and various modifications and variations may be made to the embodiment according to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment according to the present invention should be included in the protection scope of the embodiment according to the present invention.

Claims

1. A dual motor control system comprising a first motor (12) and a second motor (14), characterized by further comprising:

a main circuit (10) having a plurality of phase lines, the first motor (12) being connected to the main circuit (10) via the plurality of phase lines;

a first starting device (120) connected to said main circuit (10) by a plurality of said phase lines, said first starting device (120) being connected in series with said first electric motor (12) and being intended to start said first electric motor (12);

-detection means (16), said detection means (16) being intended to detect a current or a voltage on said main circuit (10);

the controller (18) is respectively connected with the detection device (16) and the first starting device (120), and the controller (18) is used for controlling the starting and the stopping of the first starting device (120) according to the detection result of the detection device (16);

among a plurality of phase lines connected with the input end of the first starting device (120), and among a plurality of phase lines connected with the output end of the first starting device (120), at least two phase lines are respectively connected with the detection device (16), and the two phase lines connected with the detection device (16) are out of phase; or

Said detection means (16) being built into said first activation means (120);

the plurality of phase lines comprises a first phase line (100), a second phase line (102) and a third phase line (104);

the input end of the first starting device (120) is connected with a plurality of phase lines, and the first phase line (100) is connected with the detection device (16);

the output end of the first starting device (120) is connected with a plurality of phase lines, and the second phase line (102) or the third phase line (104) is connected with the detection device (16).

2. The dual-motor control system of claim 1,

the first starting device (120) is a soft starter or a frequency converter or a contactor.

3. The dual-motor control system of claim 2, further comprising:

a power source (126);

an intermediate relay (128), one end of the intermediate relay (128) is connected with the power supply (126), the other end of the intermediate relay (128) is connected with the soft starter, and the intermediate relay (128) is used for outputting a control signal;

the power supply (126) is also connected with the input end of the soft starter, and the power supply (126) is used for supplying power to the intermediate relay (128) and the soft starter.

4. The dual-motor control system of claim 2, further comprising:

a first circuit breaker (122), through which the first actuation device (120) is connected to the main circuit (10); and/or

A first contactor (124) arranged in parallel with the soft starter, or the first contactor (124) is built in the soft starter.

5. The dual-motor control system of claim 1, further comprising:

a second contactor (142) connected to the main circuit (10) by a plurality of phase lines;

the second motor (14) is connected with the main loop (10) through the second contactor (142) and the phase lines, and the second contactor (142) is used for starting the second motor (14).

6. The dual-motor control system of claim 5, further comprising:

a second circuit breaker (140), the second contactor (142) being connected to the main circuit (10) through the second circuit breaker (140);

a thermal relay (144), through which the second electric machine (14) is connected to the second contactor (142).

7. The dual-motor control system of claim 6,

in a plurality of phase lines between the second circuit breaker (140) and the second contactor (142), at least two of the phase lines are respectively connected with one detection device (16), and the detection devices (16) are also connected with the controller (18).

8. The dual-motor control system of claim 7,

the controller (18) is further connected with the second contactor (142), and the controller (18) is further used for controlling the opening and closing of the second contactor (142) according to the detection result of the detection device (16).

9. An engineering apparatus, comprising:

an apparatus body (20);

the dual-motor control system (1) of any one of claims 1 to 8, provided on said apparatus body (20).