Motor control device

Abstract

The application provides a motor control device, which comprises a control unit, a contactor and at least two groups of conversion type relay groups; the at least two groups of conversion type relay groups comprise a first group of conversion type relays; the control unit is used for controlling the first group of conversion type relays to be in an off state and controlling the contactor to be in a conduction state when a first operation instruction for controlling the motor to rotate forward is received, so that the winding of the motor obtains a forward current for driving the motor to rotate forward; and the control unit is used for controlling the first group of conversion type relays and the contactor to be in a conduction state respectively when a second operation instruction for controlling the motor to rotate reversely is received, so that the power supply of the motor is commutated and the winding of the motor obtains a reverse current for driving the motor to rotate reversely. Thus, the motor forward and reverse rotation control is realized by the single contactor and the conversion type relay group, and the control unit is used for the cooperative control of the contactor and the relay, so that the application has the advantages of simplified structure, reliable operation and high intelligent degree.

Description

Technical Field

[0001] This application relates to the field of motor control technology, specifically to a motor control device. Background Technology

[0002] In industrial applications such as conveyor belts, traditional motor forward and reverse rotation control typically employs a scheme of two contactors in conjunction with an overload relay. However, with advancements in contactor technology, their electrical lifespan far exceeds practical requirements. Continuing to use this configuration not only wastes resources but also significantly increases system costs. Utility Model Content

[0003] To address the shortcomings of existing technologies, this application provides a motor control device that has the advantages of reducing system costs, improving control reliability, and achieving intelligent control.

[0004] This application provides a motor control device, the device including a control unit, a contactor, and at least two sets of changeover relays; the contacts of the contactor are connected in series in the power supply circuit of the motor; the at least two sets of changeover relays include a first changeover relay group, the contacts of the first changeover relay group are connected in series in the commutation circuit of the motor windings, and the control unit is electrically connected to the first changeover relay group and the contactor respectively; The control unit is configured to, upon receiving a first operation command to control the motor to rotate forward, control the first switching relay group to be in the off state and control the contactor to be in the on state, so that the windings of the motor receive a forward current to drive the motor to rotate forward; and upon receiving a second operation command to control the motor to rotate in reverse, control the first switching relay group and the contactor to be in the on state, so that the power supply to the motor is switched and the windings of the motor receive a reverse current to drive the motor to rotate in reverse.

[0005] The motor control device provided in this application embodiment achieves forward and reverse motor control through a single contactor and a set of switching relays. Combined with the coordinated control of the contactor and relays by the control unit, it can reduce hardware costs, simplify the structure, ensure reliable operation, and enhance the level of intelligence. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1This is one of the schematic diagrams of a motor control device provided in an embodiment of this application.

[0008] Figure 2 This is a second schematic diagram of a motor control device provided in an embodiment of this application.

[0009] Figure 3 This is the third schematic diagram of the motor control device provided in the embodiments of this application.

[0010] Figure 4 This is a schematic diagram of an application scenario for the motor control device provided in the embodiments of this application.

[0011] Figure 5 This is a schematic diagram illustrating another application scenario of the motor control device provided in the embodiments of this application. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use this application. In the following description, details are set forth for illustrative purposes. It should be understood that those skilled in the art will recognize that this application can be implemented without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid unnecessary detail that would obscure the description of this application. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0015] The terms "first," "second," etc., used in this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the listed steps or modules, but may optionally include steps or modules not listed, or may optionally include other steps or modules inherent to these processes, methods, products, or devices.

[0016] In this article, "first terminal," "second terminal," "third terminal," "fourth terminal," etc., are used to describe the ports where a circuit (or a sub-circuit or a circuit branch) connects to other circuits (or sub-circuits or circuit branches), or to describe the ports where electrical signals are connected to a circuit (or a sub-circuit or a circuit branch). Different circuits (or sub-circuits or circuit branches) may have ports for external connection. Here, for each circuit (or sub-circuit or circuit branch), the ports used to control whether the circuit (or sub-circuit or circuit branch) operates are named using terms such as "control terminal," and other included ports are distinguished by the naming convention of first terminal, second terminal, etc. In the following descriptions, when referring to the first, second, or third terminal of a circuit (or sub-circuit or circuit branch), the above description can be used as a reference, and further elaboration will not be provided.

[0017] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily imply that all embodiments are the same, nor are they independent or alternative embodiments mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0018] In one embodiment, this application provides a motor control device, such as... Figure 1 As shown, Figure 1This is one of the schematic diagrams of a motor control device provided in the embodiments of this application; the motor control device 100 includes a control unit 101, a contactor 102, and at least two sets of changeover relay groups 103; the contacts of the contactor 102 are connected in series in the power supply circuit of the motor; the at least two sets of changeover relay groups include a first changeover relay group 1031, the contacts of the first changeover relay group 1031 are connected in series in the commutation circuit of the motor windings, and the control unit 101 is electrically connected to the first changeover relay group 1031 and the contactor 102 respectively.

[0019] The control unit 101 is configured to, upon receiving a first operation command to control the motor to rotate forward, control the first changeover relay group 1031 to be in the off state and control the contactor 102 to be in the on state, so that the motor windings receive the forward current to drive the motor to rotate forward; and upon receiving a second operation command to control the motor to rotate in reverse, control the first changeover relay group 1031 and the contactor 102 to be in the on state, so that the power supply to the motor is switched and the motor windings receive the reverse current to drive the motor to rotate in reverse.

[0020] The control unit 101 can be an electronic controller with logic processing capabilities, implemented using a programmable logic controller or microprocessor, responsible for parsing operation instructions and outputting control signals; the control unit 101 can also be called the main control unit. The contactor 102 can be an electromagnetic switching device with main contact switching capability, such as a three-pole AC contactor, used to control the on / off state of the motor's main circuit power supply. The changeover relay group 103 can be an electromagnetic relay combination containing normally open and normally closed contacts, such as a dual-contact bistable relay, which changes the motor winding wiring configuration by switching contacts. Power commutation refers to reversing the current direction by changing the winding wiring sequence; specifically, phase sequence adjustment is achieved by switching the relay contact connection relationship.

[0021] Specifically, when the operating unit sends a forward rotation command, the control unit supplies power to the contactor coil, closing its main contacts while simultaneously de-energizing the changeover relay group. At this time, the motor windings form a forward current path through the normally closed contacts of the relay group, driving the motor to rotate forward. Upon receiving a reverse rotation command, the control unit simultaneously supplies power to both the contactor coil and the changeover relay group. The contactor main contacts remain closed, while the relay group contacts switch to the normally open state, changing the winding wiring sequence to form a reverse current path. The alternating operation of the two relay groups is controlled by the control unit's timing mechanism to prevent short circuits during commutation.

[0022] This application transfers the commutation function to a lower-cost switching relay group, reducing the number of contactors used while ensuring reliable commutation. Simultaneously, the control unit integrates overload protection and communication functions, eliminating the need for additional overload relays and communication modules, thus simplifying the internal wiring structure of the control cabinet. In this way, this application effectively reduces equipment manufacturing costs in conveyor belt control scenarios, and reduces contact wear points through a single contactor structure, improving system reliability. The integrated control unit enables overload current detection and remote communication, supporting real-time monitoring of motor operating status and meeting the needs of intelligent transformation of modern production lines.

[0023] In one embodiment, such as Figure 2 and Figure 3 As shown, Figure 2 A second schematic diagram of the motor control device provided in the embodiments of this application; Figure 3 The third schematic diagram of the motor control device provided in the embodiment of this application is shown. The motor control device 100 also includes an operation unit 104, which is electrically connected to the control unit 101 and is used to send operation instructions to the control unit 101 and display the motor's operating status and fault type. The operation instructions include a first operation instruction and a second operation instruction.

[0024] The operation unit 104 can be an interactive module connected to the control unit 101. Specifically, it can be implemented using hardware components with buttons and a display screen. For example, the operation buttons can be integrated with a microprocessor, and the display screen can be an LCD panel used to receive user input commands and provide feedback on the device status. As an example, the operation unit 104 can be a human-machine interface unit (HMI).

[0025] The operation command can be a trigger signal to control the motor's movement. Specifically, it can be implemented using high or low level signals or digital coded signals. For example, a pulse signal is generated when a button is pressed, which is then parsed by the control unit to execute the corresponding operation.

[0026] The operating status can be the current working mode of the motor, which can be determined by detecting the on / off state of the contactor and relay. For example, when the contactor is on and the relay is off, it is determined to be in the forward rotation state, and this state is encoded as text or icons on the display panel.

[0027] The fault type can be an abnormal situation that occurs during motor operation. Specifically, it can be classified according to the detection results of the current acquisition unit or the power supply unit. For example, when the current exceeds the threshold, it is determined to be an overload fault, and when the power supply is missing a phase, it is determined to be a phase loss fault, and the corresponding warning information is output on the display panel.

[0028] Specifically, the operating unit receives user input commands for forward rotation, reverse rotation, or stop via buttons and converts these commands into electrical signals, which are then transmitted to the control unit. The control unit controls the on / off states of the contactor and the changeover relay group according to the commands, while simultaneously feeding back the motor's current operating status (e.g., forward, reverse, or stopped) and the detected fault type (e.g., overload or power phase loss) to the operating unit's display panel in real time. For example, when the user presses the forward button, the operating unit generates the first operating command. Upon receiving this command, the control unit closes the changeover relay group and turns on the contactor, allowing the motor windings to receive forward current; simultaneously, the "Forward Operation" indicator light illuminates on the display panel. If the current acquisition unit detects an overload, the control unit sends the fault type information to the operating unit, the display panel switches to an "Overload Fault" prompt, and an alarm is triggered.

[0029] As an example, the operation instructions can be manually input; the operating status can include forward rotation, reverse rotation, and stop; the fault types can include overload and phase loss. The motor control device 100 may also include a status indication unit, which is electrically connected to the main control unit and includes a forward rotation indicator light, a reverse rotation indicator light, an overload alarm light, and a phase loss alarm light, which are used to indicate the forward and reverse rotation operating status of the motor and the overload and phase loss fault status, respectively.

[0030] This application integrates an operating unit, achieving status visualization while reducing hardware costs. For example, in the event of a phase loss fault, the operating unit can directly display the fault type, avoiding secondary damage caused by blindly restarting the equipment. Thus, this application solves the problem of traditional motor control devices lacking status feedback. Operators can monitor the motor's operating status and fault type in real time through the display panel. For instance, in the event of an overload, the cause of abnormal current can be quickly located, and in the event of a phase loss, the power supply line can be checked promptly, thereby reducing downtime for troubleshooting and improving maintenance efficiency. Furthermore, the communication function between the operating unit and electronic equipment provides an extended foundation for remote monitoring, such as uploading fault information to the central control system for centralized management.

[0031] In one embodiment, the operation unit 104 further includes operation buttons and a display panel; the operation instructions also include a third operation instruction to control the motor to stop; the operating state includes the motor rotating forward, the motor rotating in reverse, or the motor stopped; the fault types include at least overload fault or phase loss fault.

[0032] Operation buttons are used to input operation commands.

[0033] The display panel is used to show the running status.

[0034] The operation buttons can be devices that trigger signal input through physical contacts. Specifically, they can be implemented using metal contact switches with self-locking function, used to transmit forward, reverse, or stop commands to the control unit.

[0035] The display panel can be a component for visually displaying the status of the equipment. Specifically, it can be implemented using an LCD screen or an LED indicator array to display the current operating mode and fault information of the motor in real time.

[0036] The third operation command can be a signal to trigger the motor to stop running. Specifically, it can be generated by pressing and holding the operation button or by pressing the independent stop button, and is used to cut off the contactor power supply circuit.

[0037] The operating status can be the motor's condition when it is rotating forward, rotating in reverse, or stationary. Specifically, the control unit can collect the status of the contactor and relay group to determine the status, and then display it in categories on the display panel.

[0038] The fault type can be an electrical problem that causes abnormal motor operation. Specifically, it can be identified through the detection module of the current acquisition unit or the power supply unit. For example, overload faults are triggered by the current threshold, and phase loss faults are triggered by the power line voltage detection.

[0039] Specifically, the operation buttons are configured to receive user commands for forward rotation, reverse rotation, or stop, and transmit the signals to the control unit. Based on the type of command received, the control unit switches the operating state of the contactor and the changeover relay group, while simultaneously providing real-time feedback on the motor's current operating mode and fault information to the display panel. For example, when an overload fault is detected, the control unit cuts off the contactor's power supply and illuminates the corresponding fault indicator light on the display panel. The display panel further categorizes the operating status into forward rotation, reverse rotation, and stop, using different colors or icons for easy identification of equipment conditions by the operator.

[0040] As an example, the operation unit 104 is a human-machine operation unit. The human-machine operation unit may include operation buttons (e.g., forward rotation button, reverse rotation button, emergency stop button) and a display panel. The operation buttons are used for manual input of operation commands, and the display panel is used to display the operating status of the motor (e.g., forward rotation, reverse rotation, stop) and fault type (e.g., overload, phase loss).

[0041] This application integrates operation buttons and a display panel, combining operation command input and status feedback into a single unit, reducing operational complexity. It also supports intuitive display of various faults such as overload and phase loss, shortening fault diagnosis time. Thus, this application achieves integrated operation command input and operating status feedback in motor control, simplifying equipment interaction processes and improving operational efficiency. Furthermore, by categorizing and displaying fault types, maintenance personnel can quickly locate the cause of abnormalities, reducing equipment downtime.

[0042] In one embodiment, such as Figure 2 and Figure 3 As shown, the motor control device 100 also includes a communication unit 105, which is electrically connected to the control unit 101 and the electronic equipment, and is used to send operation commands input by the electronic equipment to the control unit 101 and to feed back alarm information corresponding to the fault type of the motor to the electronic equipment.

[0043] The communication unit 105 is a module that enables information exchange between the control unit 101 and external electronic devices. Specifically, it can be implemented using an RS-485 bus, CAN bus, or wireless communication module. Its function is to transmit remote operation commands to the control unit and simultaneously upload fault alarm information to the electronic devices. The electronic devices can be terminal devices capable of sending control commands and receiving feedback information, specifically industrial PLCs, touch screens, or host computer systems. Their function is to extend the remote operation capabilities and data monitoring functions of the control device.

[0044] Specifically, the communication unit 105 establishes a connection with the electronic equipment via wired or wireless communication protocols. When the electronic equipment issues forward, reverse, or stop commands, the communication unit transmits the commands to the control unit, triggering the corresponding relay group and contactor to operate. When the motor experiences overload, phase loss, or other faults, the control unit encodes the fault type into a specific alarm signal and transmits it to the electronic equipment in real time via the communication unit. For example, it displays prompts such as "Overload Fault E01" or "Phase Loss Fault E02" on the electronic equipment interface. In this process, the communication unit serves as both a command transmission channel and a status feedback interface, forming a bidirectional data link.

[0045] As an example, the communication unit 105 may include an RS485 communication module for transmitting operation instructions and providing fault information feedback between the control unit 101 and an external automation system (e.g., a PLC or an industrial computer).

[0046] This application, by adding a communication unit, enables the motor's operating status to be acquired by external devices in real time, and fault alarm information can be directly pushed to the monitoring terminal. For example, in a conveyor belt system, operators can directly issue reverse commands through the host computer in the central control room, while simultaneously receiving overload alarm information, without requiring on-site manual intervention. Thus, this application achieves seamless integration of the motor control device and automated equipment, solving the problem of insufficient scalability caused by the lack of communication functionality in traditional solutions. Electronic equipment can quickly locate the cause of faults based on alarm information, avoiding production line downtime caused by manual troubleshooting, while the remote command transmission function reduces the safety risks of on-site operation.

[0047] In one embodiment, such as Figure 2 and Figure 3As shown, the motor control device 100 also includes a current acquisition unit 106, which is connected in series in the power supply circuit of the motor and electrically connected to the control unit 101, for acquiring the current value of the motor operation and sending it to the control unit 101.

[0048] Control unit 101 is used to determine that the motor fault type is an overload fault when the current value is greater than or equal to the overload current threshold, and to control contactor 102 to be in the off state.

[0049] The current acquisition unit 106 is a detection module for real-time monitoring of the motor's operating current. Specifically, it can be implemented using a Hall effect current sensor or a current transformer. By converting a large current into a measurable electrical signal, it enables precise monitoring of the motor's operating status. The overload current threshold can be a pre-set current protection critical value, specifically set through the control unit's internal memory. For example, it can be set to 1.2 to 1.5 times the motor's rated current to determine whether the motor is in an abnormal overload state. The overload delay threshold limits the duration for which the current exceeds the overload current threshold, specifically set to 2 to 10 seconds. This distinguishes between instantaneous current fluctuations and continuous overload faults, preventing false triggering of protection actions.

[0050] Specifically, the current acquisition unit continuously monitors the current flowing through the power supply circuit and converts the real-time current data into a voltage signal, which is then transmitted to the control unit. When the control unit detects that the current value exceeds the set overload current threshold, it activates the timing module to determine the duration of the abnormal state. For example, if the current value continues to exceed the threshold for 5 seconds, it is determined to be an overload fault, and a control signal is immediately output to de-energize the contactor coil, thereby cutting off the motor power supply circuit. In this process, the current acquisition unit and the control unit form a closed-loop detection mechanism, which avoids the response delay problem of traditional thermal relays and effectively distinguishes between short-term inrush currents and real overload conditions through time-delay judgment.

[0051] As an example, the current acquisition unit 106 transmits the acquired current signal to the control unit 101 for overload protection calculation. When the overload protection threshold is reached, the control unit 101 controls the contactor 102 to disconnect and sends an alarm signal. The operation unit 104 displays the fault or sends fault information from the communication unit 105. This application achieves digital setting of current thresholds and precise control of time-delay protection through the coordinated operation of the current acquisition unit and control unit. Simultaneously, it can directly feed overload signals back to the communication unit, providing data support for remote monitoring. Thus, this application can effectively identify continuous overload faults during motor operation, quickly cutting off the faulty circuit while avoiding false alarms and preventing winding overheating damage. For example, in scenarios where a conveyor belt stall causes a current surge, the control unit can complete overload determination and execute power-off protection in a short time, significantly shortening the response time compared to traditional thermal relays and greatly improving equipment safety.

[0052] In one embodiment, the control unit 101 is further configured to determine whether the duration of the current value being greater than or equal to the overload current threshold is greater than or equal to the overload delay threshold, and if the duration is greater than or equal to the overload delay threshold, determine that the fault type of the motor is an overload fault.

[0053] The overload current threshold can be a pre-set upper limit of the motor operating current, which can be achieved through preset parameters or by configuring an adjustable resistor. It is used to distinguish between normal operating current and abnormal overload current. The overload delay threshold can be the maximum time for which the current is allowed to exceed the overload current threshold. It can be implemented using a timer module or software timing logic to prevent false triggering of protection actions due to instantaneous current fluctuations.

[0054] Specifically, the current acquisition unit collects the current value in the motor power supply circuit in real time and transmits it to the control unit. The control unit compares the collected current value with the overload current threshold in real time. When the current value exceeds the overload current threshold, a delay judgment mechanism is activated. At this time, the control unit continuously monitors the duration of the current exceeding the limit and accumulates this time through an internal timing module. If the duration reaches or exceeds the overload delay threshold, it is determined that the motor has a continuous overload fault, and the control unit immediately outputs a shutdown signal to disconnect the power supply circuit by the contactor. If the duration does not reach the overload delay threshold, it is determined to be a momentary overload or interference signal, and no protection action is triggered.

[0055] As an example, the current acquisition unit 106 can be a current transformer or a shunt, and the control unit 101 can pre-store the motor overload current threshold and the overload delay time. When the real-time current transmitted by the current acquisition unit 106 is greater than or equal to the overload current threshold and the duration exceeds the overload delay time, the control unit 101 determines that it is an overload fault.

[0056] This application introduces a dual judgment mechanism, detecting both the current amplitude and duration, effectively distinguishing between real overloads and transient interference, thus reducing the probability of malfunctions. In this way, the application can accurately identify real overload faults during motor operation, avoiding unnecessary shutdowns caused by transient current fluctuations, while ensuring timely power cut-off in the event of sustained overloads to prevent overheating and damage to the motor windings, thereby improving the safety and reliability of the system operation.

[0057] In one embodiment, such as Figure 2 and Figure 3 As shown, the motor control device 100 also includes a power supply unit 107, which is electrically connected to the control unit 101, the contactor 102, and at least two sets of changeover relays 103, respectively. It is used to provide working power and determine whether there is a phase loss in the power supply line of the motor. When there is a phase loss in the power supply line, it determines that the fault type of the motor is a phase loss fault and transmits the phase loss fault information to the control unit. The control unit 101 is also used to control the contactor to be in the off state based on the phase loss fault information.

[0058] The power supply unit 107 provides a stable operating voltage for the control unit 101, contactor 102, and relay group. Specifically, it can be implemented using a switching power supply or a transformer with a rectifier and filter circuit. Its integrated phase loss detection function reduces the number of external detection components. The phase loss detection module is a functional unit connected to the three-phase power line via a voltage sampling circuit. Specifically, it can be implemented using a voltage comparator and logic circuitry. When any one of the three phases is missing, the voltage comparator outputs an abnormal signal, triggering the logic circuitry to generate a fault signal.

[0059] Specifically, the power supply unit is connected to the motor power supply line via three-phase input terminals, and the phase loss detection module monitors the voltage status of each phase line in real time. For example, when a phase of the three-phase power supply experiences a voltage loss due to a line disconnection or poor contact, the phase loss detection module identifies the abnormal state and generates an electrical signal that is transmitted to the control unit. Upon receiving this signal, the control unit immediately disconnects the contactor's control circuit, causing the contactor contacts to open, thereby cutting off the motor power supply circuit and preventing the motor from running in a phase loss state, which could cause the windings to overheat or be damaged. This application integrates the phase loss detection function into the power supply unit, achieving dual functionality by reusing the voltage sampling circuit of the power supply unit. This simplifies the circuit structure and avoids the cost burden of adding a separate detection module. Thus, this application can quickly cut off the power supply when a phase loss fault occurs in the motor power line, preventing equipment damage caused by motor operation with a single phase loss. Simultaneously, functional integration reduces hardware costs and installation complexity, improving the reliability and economy of the motor control system.

[0060] In one embodiment, the power supply unit 107 includes a phase loss detection module, which is electrically connected to the first, second, and third terminals of the power supply line of the motor. The module is used to detect whether there is a phase loss fault in the voltage of each phase line in the first, second, and third terminals. When any phase loss fault exists in any phase line voltage, the information of the phase loss fault is transmitted to the control unit in the form of an electrical signal.

[0061] The phase loss detection module can be an electronic detection circuit used to monitor the voltage status of each phase in a three-phase power supply line. Specifically, it can be implemented by combining a voltage sensor and a comparison circuit. By acquiring the three-phase voltage signal in real time and comparing it with a preset threshold, it can determine whether there is a phase loss.

[0062] Electrical signal transmission can convert phase loss fault information into a signal type that can be recognized by the control unit. Specifically, it can be achieved using digital level signals or pulse signals. For example, the detection result can be converted into a high / low level signal and transmitted to the control unit through an optocoupler isolation circuit.

[0063] Specifically, the phase loss detection module collects the voltage values ​​of each phase in the three-phase power line using voltage sensors and inputs the collected data into a comparison circuit. When the voltage of a certain phase falls below a preset threshold or disappears completely, the comparison circuit triggers the phase loss judgment logic, generating a corresponding fault signal. This signal is processed by an isolation circuit and transmitted to the control unit in the form of an electrical signal. Upon receiving the signal, the control unit immediately disconnects the contactor to break the motor power circuit, thereby preventing damage to the motor due to phase loss operation.

[0064] As an example, the power supply unit 107 includes a phase loss detection module, which is electrically connected to the L1, L2, and L3 terminals of the motor power supply main line. By detecting whether the voltage of each phase line is normal, it determines whether there is a phase loss and transmits the phase loss determination result to the control unit 101 in the form of an electrical signal. This application employs an electronic detection module, capable of real-time monitoring of the three-phase voltage status and rapid triggering of protection actions, significantly improving the detection accuracy and response speed of phase loss faults. Furthermore, by directly transmitting fault information via electrical signals, it avoids the potential malfunctions caused by mechanical contacts in traditional solutions. Thus, this application achieves rapid and accurate detection of phase loss faults in motor power lines, and ensures the reliability of protection actions through an electronic signal transmission mechanism, effectively preventing overheating or burnout of motor windings due to phase loss, while also simplifying the circuit structure and reducing maintenance costs.

[0065] In one embodiment, such as Figure 2As shown, the first changeover relay group 1031 includes a first changeover relay K1 and a second changeover relay K2; the first changeover relay K1 includes a first moving contact 11, a first normally closed contact 12, and a first normally open contact 13; the second changeover relay K2 includes a second moving contact 21, a second normally closed contact 22, and a second normally open contact 23; the first terminal L1 of the motor winding is electrically connected to the first moving contact 11, the second terminal L2 is electrically connected to the second moving contact 21, the first normally closed contact 12 and the second normally open contact 23 are respectively electrically connected to the first terminal of the motor power supply; the first normally open contact 13 and the second normally closed contact 22 are respectively electrically connected to the second terminal of the motor power supply.

[0066] When the first changeover relay K1 and the second changeover relay K2 are de-energized, the first moving contact 11 and the first normally closed contact 12 are connected, and the second moving contact 21 and the second normally closed contact 22 are connected, so that the motor is in the forward rotation state.

[0067] When the first changeover relay K1 and the second changeover relay K2 are energized, the first moving contact 11 is connected to the first normally open contact 13, and the second moving contact 21 is connected to the second normally open contact 23, causing the motor to be in reverse state.

[0068] The first changeover relay K1 can be an electromagnetic switch device with moving, normally closed, and normally open contacts. Specifically, it can be implemented using an intermediate relay with three sets of contacts. The conduction state of the moving contact and the normally closed or normally open contact is controlled by energizing or de-energizing the coil. The second changeover relay has the same structure as the first changeover relay. The two are connected by cross-connection of contacts to form a commutation circuit, allowing the two ends of the power supply to be connected to the terminals of the motor winding under different states, thereby realizing the switching of current direction. The normally closed contact can be a contact that remains conductive when the relay coil is not energized, and the normally open contact can be a contact that conducts when the relay coil is energized. The moving contact serves as a switchable connection point, and the contact switching is achieved by electromagnetic force.

[0069] Specifically, when the first changeover relay K1 and the second changeover relay K2 are de-energized, the first moving contact 11 is connected to the first normally closed contact 12, and the second moving contact 21 is connected to the second normally closed contact 22. At this time, the first power supply terminal is connected to the first winding terminal through the first normally closed contact, and the second power supply terminal is connected to the second winding terminal through the second normally closed contact, forming a forward current path and driving the motor to rotate forward. When both relays are energized, the first moving contact 11 switches to be connected to the first normally open contact 13, and the second moving contact 21 switches to be connected to the second normally open contact 23. At this time, the first power supply terminal is connected to the second winding terminal through the second normally open contact 23, and the second power supply terminal is connected to the first winding terminal through the first normally open contact 13, reversing the current direction and driving the motor to rotate in reverse. By controlling the on / off state of the two relays, the power supply phase sequence is switched, completing the forward and reverse rotation control of the motor.

[0070] In some specific implementations, the first changeover relay K1 and the second changeover relay K2 can be double-contact relays with a mechanical interlocking structure to ensure that the two sets of contacts cannot be turned on at the same time; the first and second power supply terminals can correspond to two phases in the three-phase power supply, such as phase L1 and phase L2; the first and second terminals of the winding can correspond to the U-phase and V-phase terminals of the motor stator winding.

[0071] As an example, the contacts in the motor control device can be air switches, and the switch status detection interface can include an air switch status detection interface. The motor control device includes an air switch status detection interface. If the air switch is closed, the external acquisition terminal detects a high level; otherwise, it detects a low level. The resistors R1 and R2 added to the motor control device are for current limiting and voltage division, and also serve as pull-up resistors.

[0072] This application replaces contactors with two sets of changeover relays, leveraging their miniaturization and low cost to reduce the number of hardware components while maintaining commutation functionality. Furthermore, the cross-connection design of the contacts avoids the risk of short circuits in the commutation circuit. Thus, this application enables motor forward and reverse rotation control at a lower cost, simplifies the circuit structure, and improves reliability. Simultaneously, the contact interlocking mechanism prevents phase-to-phase short circuits in the power supply, solving the problems of large size and high cost associated with traditional dual-contactor solutions. This makes it suitable for industrial scenarios with strict requirements for economy and space.

[0073] In one embodiment, such as Figure 3 As shown, at least two sets of changeover relay groups 103 also include a second changeover relay group 1032, which includes two sets of changeover relays. The second changeover relay group is connected to the control unit and is used to prevent the two sets of relays from being turned on at the same time during power commutation, which would cause a short circuit in the commutation circuit.

[0074] The second changeover relay group 1032 can be a combination unit consisting of two sets of changeover relays with interlocking functions. Specifically, it can be implemented using electromagnetic relays containing normally closed contacts, with a contact interlocking mechanism preventing both sets of relays from being energized simultaneously. The interlocking mechanism can be achieved by connecting the relay contacts in series with the coil of the other relay. Specifically, it can be implemented by connecting the normally closed contacts of the first set of relays in series with the coil circuit of the second set of relays. When the first set of relays is energized, the energizing path of the second set of relays is forcibly cut off.

[0075] Specifically, during power commutation, when the control unit sends a control signal to the second set of changeover relays, only one set of changeover relays is allowed to be in the on state at a time. When the first set of changeover relays is energized, its normally closed contact disconnects the coil power supply circuit of the other set of relays. At this point, even if the other set of relays receives an erroneous signal, it cannot be energized. For example, when the third changeover relay is energized, its normally closed contact cuts off the coil circuit of the fourth changeover relay; similarly, when the fifth changeover relay is energized, it forcibly cuts off the power supply path of the sixth changeover relay. This interlocking structure ensures that the two sets of relays cannot be energized simultaneously, thereby eliminating the risk of a short circuit in the commutation circuit.

[0076] This application utilizes an electrical control method with relay contact interlocking, which reduces hardware costs while improving reliability. Existing contactors are bulky and lack communication interfaces, while the changeover relay group used in this solution can be directly integrated with the control unit, facilitating remote communication control. Thus, this application effectively solves the problem of short circuits caused by relay malfunctions during commutation operations, replacing traditional mechanical interlocking devices with an electrical interlocking mechanism, simplifying the structure and reducing manufacturing costs. This design further expands the applicability of motor control devices, enabling them to be compatible with multiple communication protocols and achieve remote status monitoring in automation systems.

[0077] In one embodiment, such as Figure 3 As shown, the first set of two sets of changeover relays includes the third changeover relay K3 and the fourth changeover relay K4; the second set of two sets of changeover relays includes the fifth changeover relay K5 and the sixth changeover relay K6.

[0078] The normally closed contact of the third changeover relay K3 is connected in series with the coil of the fourth changeover relay K4, and the normally closed contact of the fourth changeover relay K4 is connected in series with the coil of the third changeover relay K3, so that the third changeover relay K3 and the fourth changeover relay K4 are interlocked.

[0079] The normally closed contact of the fifth changeover relay K5 is connected in series with the coil of the sixth changeover relay K6, and the normally closed contact of the sixth changeover relay K6 is connected in series with the coil of the fifth changeover relay K5, so that the fifth changeover relay K5 and the sixth changeover relay K6 are interlocked.

[0080] As an example, the normally closed contact of K3 is connected in series with the coil of K4, and the normally closed contact of K4 is connected in series with the coil of K3; the normally closed contact of K5 is connected in series with the coil of K6, and the normally closed contact of K6 is connected in series with the coil of K5; this achieves electrical interlocking between K3 and K4, and between K5 and K6, which helps to achieve safe switching of the motor commutation circuit, and at the same time prevents two sets of relays from conducting simultaneously, causing a short circuit in the commutation circuit.

[0081] As an example, such as Figure 4 and Figure 5 As shown, Figure 4 This is a schematic diagram illustrating an application scenario of the motor control device provided in an embodiment of this application; Figure 5 This is a schematic diagram illustrating another application scenario of the motor control device provided in the embodiments of this application; combined with Figures 1 to 5 The main topology consists of a K1 / K2 changeover relay, contactor 102, and current acquisition unit 106. When K1 / K2 is in the normally closed position, contactor 102 closes, and the motor rotates forward. When K1 / K2 is in the normally open position, L1 and L2 are reversed, contactor 102 closes, and the motor rotates in reverse. The operation logic is implemented by control unit 101, and operation commands are transmitted to control unit 101 by operation unit 104 or communication unit 105. Current acquisition unit 106 transmits the acquired current signal to control unit 101, which performs overload protection calculations. When the overload protection threshold is reached, the main control unit controls contactor 102 to open and sends an alarm signal. Operation unit 104 displays the fault or sends fault information from communication unit 105. The control unit 101 obtains electrical energy and main line phase loss information from the power supply unit 107. If a phase loss is detected, the control unit 101 controls the contactor 102 to open and sends an alarm signal. The operation unit 104 displays the fault or sends fault information from the communication unit 105. The commutation circuit is composed of K3, K4, K5, and K6, with K3 and K4 interlocked and K5 and K6 interlocked.

[0082] The above provides a detailed description of a motor control device provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A motor control device, characterized in that, The device includes a control unit, a contactor, and at least two sets of changeover relays; the contacts of the contactor are connected in series in the power supply circuit of the motor; the at least two sets of changeover relays include a first changeover relay set, the contacts of which are connected in series in the commutation circuit of the motor windings, and the control unit is electrically connected to the first changeover relay set and the contactor respectively. The control unit is configured to, upon receiving a first operation command to control the motor to rotate forward, control the first switching relay group to be in the off state and control the contactor to be in the on state, so that the windings of the motor receive a forward current to drive the motor to rotate forward; and upon receiving a second operation command to control the motor to rotate in reverse, control the first switching relay group and the contactor to be in the on state, so that the power supply to the motor is switched and the windings of the motor receive a reverse current to drive the motor to rotate in reverse.

2. The motor control device according to claim 1, characterized in that, The motor control device further includes an operation unit, which is electrically connected to the control unit and is used to send operation instructions to the control unit and display the operating status and fault type of the motor. The operation instructions include the first operation instruction and the second operation instruction.

3. The motor control device according to claim 2, characterized in that, The operating unit also includes operating buttons and a display panel; the operating instructions also include a third operating instruction to stop the motor; the operating states include the motor rotating forward, the motor rotating in reverse, or the motor stopped; the fault types include at least overload faults or phase loss faults. The operation button is used to input the operation command; The display panel is used to display the operating status.

4. The motor control device according to claim 1, characterized in that, The motor control device also includes a communication unit, which is electrically connected to the control unit and the electronic device, and is used to send the operation command input by the electronic device to the control unit and to provide the electronic device with alarm information corresponding to the fault type of the motor.

5. The motor control device according to claim 1, characterized in that, The motor control device also includes a current acquisition unit, which is connected in series in the power supply circuit of the motor and electrically connected to the control unit, for acquiring the current value of the motor and sending it to the control unit; The control unit is used to determine that the fault type of the motor is an overload fault when the current value is greater than or equal to the overload current threshold, and to control the contactor to be in the off state.

6. The motor control device according to claim 5, characterized in that, The control unit is further configured to determine whether the duration for which the current value is greater than or equal to the overload current threshold is greater than or equal to the overload delay threshold, and when the duration is greater than or equal to the overload delay threshold, determine that the fault type of the motor is an overload fault.

7. The motor control device according to claim 1, characterized in that, The motor control device further includes a power supply unit, which is electrically connected to the control unit, the contactor, and the at least two sets of conversion relays, respectively, for providing working power and determining whether there is a phase loss in the power supply line of the motor. When there is a phase loss in the power supply line, the fault type of the motor is determined to be a phase loss fault, and the information of the phase loss fault is transmitted to the control unit. The control unit is also used to control the contactor to be in the off state based on the information of the phase loss fault.

8. The motor control device according to claim 7, characterized in that, The power supply unit includes a phase loss detection module, which is electrically connected to the first, second, and third terminals of the power supply line of the motor. It is used to detect whether the phase loss fault exists in the voltage of each phase line in the first, second, and third terminals. When the phase loss fault exists in any one of the phase line voltages, the information of the phase loss fault is transmitted to the control unit in the form of an electrical signal.

9. The motor control device according to claim 1, characterized in that, The first changeover relay group includes a first changeover relay and a second changeover relay; the first changeover relay includes a first moving contact, a first normally closed contact, and a first normally open contact; the second changeover relay includes a second moving contact, a second normally closed contact, and a second normally open contact; the first terminal of the motor winding is electrically connected to the first moving contact, and the second terminal is electrically connected to the second moving contact; the first normally closed contact and the second normally open contact are respectively electrically connected to the first terminal of the motor's power supply; the first normally open contact and the second normally closed contact are respectively electrically connected to the second terminal of the motor's power supply. When the first changeover relay and the second changeover relay are de-energized, the first moving contact is connected to the first normally closed contact, and the second moving contact is connected to the second normally closed contact, so that the motor is in the forward rotation state; When the first changeover relay and the second changeover relay are energized, the first moving contact is connected to the first normally open contact, and the second moving contact is connected to the second normally open contact, causing the motor to be in reverse state.

10. The motor control device according to any one of claims 1-9, characterized in that, The at least two sets of switching relay groups further include a second switching relay group, which includes two sets of switching relays. The second switching relay group is connected to the control unit and is used to prevent the two sets of relays from being turned on simultaneously during the power commutation, which would cause a short circuit in the commutation circuit.

11. The motor control device according to claim 10, characterized in that, The first set of the two sets of changeover relays includes a third changeover relay and a fourth changeover relay; the second set of the two sets of changeover relays includes a fifth changeover relay and a sixth changeover relay. The normally closed contact of the third changeover relay is connected in series with the coil of the fourth changeover relay, and the normally closed contact of the fourth changeover relay is connected in series with the coil of the third changeover relay, so that the third changeover relay and the fourth changeover relay are interlocked. The normally closed contact of the fifth changeover relay is connected in series with the coil of the sixth changeover relay, and the normally closed contact of the sixth changeover relay is connected in series with the coil of the fifth changeover relay, so that the fifth changeover relay and the sixth changeover relay are interlocked.

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