Variable frequency transmission control system and control method

Abstract

The invention discloses a variable-frequency transmission control system and a variable-frequency transmission control method. The frequency conversion transmission control system comprises a communication switching device, at least two frequency conversion devices and at least two state switching devices. The communication switching device is connected with the at least two frequency conversion devices; the at least two frequency conversion devices are connected with the at least two state switching devices in a one-to-one correspondence manner; the communication switching device is also connected with at least two state switching devices; wherein the communication switching device is used for connecting at least two controllers; each state switching device is used for connecting at least two motor assemblies; the communication switching device is used for establishing communication connection between the controller and the target frequency conversion device; and the communication switching device is also used for controlling the working state of the state switching device, so that the target motor assembly in the at least two motor assemblies is in a running state. Therefore, the equipment cost can be reduced, and the utilization efficiency of the system is improved.

Description

Technical Field

[0001] The present application relates to the field of transmission control, and in particular to a variable frequency transmission control system and control method. Background Art

[0002] Medium-voltage main drive control systems for large motors are widely used in automotive testing systems, large-scale new energy testing systems, and large metallurgical rolling mill systems. Medium-voltage AC / DC variable-frequency speed control systems are widely used for the main drive control systems of these large-scale equipment due to their high dynamic performance, control accuracy, efficient energy feedback, and energy-saving technologies. However, due to diverse needs, the cost of a single system is prohibitive for small and medium-sized enterprises. Furthermore, some equipment is inefficiently utilized, resulting in wasted resources. Summary of the Invention

[0003] In view of this, embodiments of the present application at least provide a variable frequency transmission control system and a control method.

[0004] The technical solution of the embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a variable frequency transmission control system, the variable frequency transmission control system comprising a communication switching device, at least two frequency conversion devices, and at least two state switching devices;

[0006] The communication switching device is connected to the at least two frequency conversion devices; the at least two frequency conversion devices are connected to the at least two state switching devices in a one-to-one correspondence; the communication switching device is also connected to the at least two state switching devices; wherein,

[0007] The communication switching device is used to connect at least two controllers; each of the state switching devices is used to connect at least two motor assemblies;

[0008] The communication switching device is used to establish a communication connection between the controller and a target frequency conversion device; the target frequency conversion device is at least one frequency conversion device among the at least two frequency conversion devices;

[0009] The communication switching device is further used to control the working state of the state switching device so that the target motor component of the at least two motor components is in the running state;

[0010] The target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

[0011] In a second aspect, an embodiment of the present application provides a control method based on a variable frequency transmission control system, the method being applied to a communication switching device of a variable frequency transmission control system; the variable frequency transmission control system further comprising at least two frequency conversion devices and at least two state switching devices; the communication switching device being connected to the at least two frequency conversion devices; the at least two frequency conversion devices being connected to the at least two state switching devices in a one-to-one correspondence; the communication switching device being further connected to the at least two state switching devices; the control method comprising:

[0012] Establishing a communication connection between the controller and a target frequency conversion device; the target frequency conversion device is at least one frequency conversion device among the at least two frequency conversion devices connected to the communication switching device;

[0013] The working state of the state switching device is controlled so that the target motor component among the at least two motor components is in the running state; the target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

[0014] In an embodiment of the present application, a variable frequency drive control system includes a communication switching device, at least two frequency conversion devices, and at least two state switching devices. The communication switching device is used to establish a communication connection between the controller and the target frequency conversion device, and to control the working state of the state switching device, so that the target motor component of the at least two motor components is in an operating state. In this way, through the communication switching device, the controller can establish a communication connection with at least one frequency conversion device, and can enable at least one frequency conversion device to transmit electrical energy to the target motor component in an operating state, so that the variable frequency drive control system can include multiple process control modes and can meet the process testing requirements of different manufacturers. Compared with the related art in which one process model is equipped with a set of frequency converter systems, the equipment cost is greatly reduced and the utilization efficiency of the system is improved.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and, together with the specification, are used to illustrate the technical solutions of the present application.

[0017] Figure 1 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 1 ;

[0018] Figure 2 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 2 ;

[0019] Figure 3 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 3 ;

[0020] Figure 4 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 4 ;

[0021] Figure 5 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 5 ;

[0022] Figure 6 A schematic diagram of the implementation process of a control method based on a variable frequency drive control system provided in an embodiment of the present application Figure 1 ;

[0023] Figure 7 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 6 ;

[0024] Figure 8 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 7 ;

[0025] Figure 9 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 8 ;

[0026] Figure 10 A schematic diagram of the structure of a variable frequency drive control system provided in the embodiment of the present application Figure 9 ;

[0027] Figure 11 A schematic diagram of the implementation process of a control method based on a variable frequency drive control system provided in an embodiment of the present application Figure 2 ;

[0028] Figure 12 A schematic diagram of the implementation process of a control method based on a variable frequency drive control system provided in an embodiment of the present application Figure 3 ;

[0029] Figure 13 Schematic diagram of the control principle of the encoder signal switching system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions of this application are further elaborated in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limiting this application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0031] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0032] The terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first / second / third" can be interchanged with a specific order or sequence where permitted so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing this application only and are not intended to limit this application.

[0034] For medium-voltage main drive control systems for large motors, medium-voltage AC-DC-AC variable frequency speed control systems are widely used due to their high dynamic performance and control accuracy, as well as their efficient energy feedback and energy-saving technologies. However, due to the diversity of needs, the cost of a single system is high, making it unaffordable for small and medium-sized enterprises. At the same time, the low utilization efficiency of some equipment results in a waste of resources. For example, manufacturer 1 has built a medium-voltage main drive control system, in which all devices included in the medium-voltage main drive control system are single, such as a controller. When manufacturer 1 conducts a process test based on process test parameters, it uses the medium-voltage main drive control system. When manufacturer 2 needs to conduct a process test, it cannot use the medium-voltage main drive control system built by manufacturer 1 because the process test parameters of manufacturer 2 and the type of device required by manufacturer 2 are different from those of manufacturer 1. This results in a low utilization rate of the medium-voltage main drive control system built by manufacturer 1, resulting in a waste of resources.

[0035] In order to solve the technical problems existing in the related art, the embodiment of the present application provides a variable frequency drive control system, such as Figure 1 As shown, the variable frequency drive control system 100 includes a communication switching device 120, at least two frequency conversion devices 130, and at least two state switching devices 140;

[0036] The communication switching device 120 is connected to the at least two frequency conversion devices 130; the at least two frequency conversion devices 130 are connected to the at least two state switching devices 140 in a one-to-one correspondence; the communication switching device 120 is also connected to the at least two state switching devices 140; wherein,

[0037] The communication switching device 120 is used to connect at least two controllers 110; each state switching device is used to connect at least two motor assemblies 200;

[0038] The communication switching device 120 is used to establish a communication connection between the controller 110 and a target frequency conversion device; the target frequency conversion device is at least one frequency conversion device 130 of the at least two frequency conversion devices 130;

[0039] The communication switching device 120 is further configured to control the working state of the state switching device 140 so that the target motor assembly in the at least two motor assemblies 200 is in the running state;

[0040] The target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

[0041] In an embodiment of the present application, the connection channel between the communication switching device and the state switching device can be a switching channel, through which the target motor component can be put into operation; the connection channel between the controller, the communication switching device, the frequency conversion device, the state switching device and the motor component can be a process channel, through which the controller can control the parameters of the frequency conversion device and the motor component to realize process testing.

[0042] Here, the controller may be a programmable logic controller (PLC). In some embodiments, at least two controllers may be PLCs of the same type or with the same functionality. In other embodiments, to meet the testing requirements of different manufacturers, at least two controllers may be PLCs of different types and / or with different functionality.

[0043] In some embodiments, different manufacturers may use different types of controllers to conduct process tests. Therefore, by providing different types of controllers in the variable frequency drive control system, the testing needs of different manufacturers can be met. Therefore, in the embodiments of the present application, the controller can be the controller to be subjected to the process test, that is, the controller can be the manufacturer's controller.

[0044] In the embodiments of the present application, the communication switching device may include multiple interfaces, each of which is configured to connect to a controller. In other words, when a manufacturer needs to conduct a process test, the manufacturer's controller can be connected to the communication switching device of the variable frequency drive control system provided in the embodiments of the present application to conduct the process test.

[0045] In embodiments of the present application, the frequency converter may be a medium-voltage frequency converter, which serves as the power system for the motor. In some embodiments, the medium-voltage frequency converter may be a medium-voltage frequency converter system using a novel high-power device, an integrated gate-commutated thyristor (IGCT), based on a midpoint-clamped three-level voltage source AC-DC-AC technology and vector control technology. In other embodiments, the frequency converter may be any device capable of providing power to the motor. The embodiments of the present application do not limit the type of frequency converter.

[0046] In an embodiment of the present application, each frequency conversion device may include a transformer, a rectifier unit, and an inverter unit. The transformer is connected to the power grid and is used to step down the AC power output by the power grid. The rectifier unit is connected to the transformer, and the rectifier unit adopts pulse width modulation (PWM) rectification. The DC bus voltage is controllable through PWM modulation rectification control, and the grid-side power factor can be controlled between -1 and 1. The inverter unit is connected to the rectifier unit, and the inverter unit adopts a motor vector control strategy and a voltage-type PWM control strategy to control each IGCT switching device of the neutral point clamped three-level inverter, so that the frequency of the output voltage and current is variable, thereby achieving high-performance operation of the motor.

[0047] In an embodiment of the present application, a state switching device is used to connect at least two motor assemblies. Each state switching device is connected to the same number of motor assemblies. In other embodiments, different state switching devices can be connected to different numbers of motor assemblies. For example, state switching device 1 is connected to two motor assemblies, and state switching device 2 is connected to three motor assemblies.

[0048] In some embodiments, the motor components connected to each state switching device can be electronic components of the same type or different types.

[0049] In an embodiment of the present application, a communication switching device is used to establish a communication connection between a controller and a target frequency conversion device; the target frequency conversion device is at least one of the at least two frequency conversion devices, and the working state of the control state switching device is controlled so that the target motor component of the at least two motor components is in a running state. In other words, the communication switching device needs to first determine the frequency conversion device to be controlled by the controller, that is, the controller establishes a communication connection with at least one frequency conversion device through the communication switching device. Then, by changing the working state of the state switching device, the target motor component of the two motor components of the state switching device corresponding to the target frequency conversion device is in a running state, so that the target frequency conversion device transmits electrical energy to the target motor component in the running state.

[0050] It is understood that in the embodiments of the present application, the controller's function is solely to adjust the parameters of the target frequency converter and target motor assembly for process testing; switching between the target frequency converter and target motor assembly is accomplished by the communication switching device. This eliminates the need for the controller to communicate with, and thus adapt to, the state switching device. Instead, the controller switches between the frequency converter and motor assembly via a dedicated communication switching device, thereby improving the efficiency and accuracy of the switching device.

[0051] Exemplarily, the variable frequency transmission control system includes a communication switching device, a first frequency conversion device, a second frequency conversion device, a first state switching device, and a second state switching device; wherein, the communication switching device is connected to the first controller and the second controller, the communication switching device is connected to the first frequency conversion device and the second frequency conversion device, the first frequency conversion device is connected to the first state switching device, the first state switching device is connected to the first motor assembly and the second motor assembly, the second frequency conversion device is connected to the second state switching device, and the second state switching device is connected to the third motor assembly and the fourth motor assembly.

[0052] The first controller can establish a communication connection with the first frequency conversion device through the communication switching device, and then the first controller switches the power output object of the first frequency conversion device between the first motor component and the second motor component through the communication switching device and the first state switching device connected to the first frequency conversion device. For example, the first motor component can be switched to the power output object of the first frequency conversion device, and the second motor component can also be switched to the power output object of the first frequency conversion device, that is, the first motor component is in an operating state, or the second motor component is in an operating state.

[0053] The first controller can also establish a communication connection with the second frequency conversion device through the communication switching device, and then the first controller switches the power output object of the second frequency conversion device in the third motor component and the fourth motor component through the communication switching device and the second state switching device connected to the second frequency conversion device. For example, the third motor component can be switched to the power output object of the second frequency conversion device, and the fourth motor component can also be switched to the power output object of the second frequency conversion device, that is, the third motor component is in an operating state, or the fourth motor component is in an operating state.

[0054] The first controller can also establish communication connections with both the first and second frequency conversion devices via the communication switching device. The first controller then switches the power output destination of the first frequency conversion device in the first and second motor assemblies, and switches the power output destination of the second frequency conversion device in the third and fourth motor assemblies, via the communication switching device, a first state switching device connected to the first frequency conversion device, and a second state switching device connected to the second frequency conversion device. The second controller can switch the power output destination in a manner similar to that of the first controller.

[0055] Continuing with the above example, when both the first frequency conversion device and the second frequency conversion device have one power output channel, and the first motor assembly and the second motor assembly are of different types, for the first controller, the variable frequency drive control system has eight control modes, namely:

[0056] 1. The first controller is connected to the first frequency conversion device, and the power output target of the first frequency conversion device is the first motor assembly; 2. The first controller is connected to the first frequency conversion device, and the power output target of the first frequency conversion device is the second motor assembly; 3. The first controller is connected to the second frequency conversion device, and the power output target of the second frequency conversion device is the third motor assembly; 4. The first controller is connected to the second frequency conversion device, and the power output target of the second frequency conversion device is the second motor assembly; 5. The first controller is connected to the first and second frequency conversion devices, and the power output target of the first frequency conversion device is the first motor assembly, and the power output of the second frequency conversion device is The target is the third motor assembly; 6. The first controller is connected to the first and second frequency conversion devices. The first frequency conversion device outputs power to the first motor assembly, and the second frequency conversion device outputs power to the fourth motor assembly; 7. The first controller is connected to the first and second frequency conversion devices. The first frequency conversion device outputs power to the second motor assembly, and the second frequency conversion device outputs power to the third motor assembly; 8. The first controller is connected to the first and second frequency conversion devices. The first frequency conversion device outputs power to the second motor assembly, and the second frequency conversion device outputs power to the fourth motor assembly. The same applies to the first controller.

[0057] That is to say, the variable frequency drive control system in the embodiment of the present application can provide multiple control modes for the controller used for process testing. After determining the target control mode among multiple control modes, the corresponding devices can be connected together based on the target control mode, thereby realizing the corresponding process tests together.

[0058] In an embodiment of the present application, a variable frequency drive control system includes a communication switching device, at least two frequency conversion devices, and at least two state switching devices. The communication switching device is used to establish a communication connection between the controller and the target frequency conversion device, and to control the working state of the state switching device, so that the target motor component of the at least two motor components is in an operating state. In this way, through the communication switching device, the controller can establish a communication connection with at least one frequency conversion device, and can enable at least one frequency conversion device to transmit electrical energy to the target motor component in an operating state, so that the variable frequency drive control system can include multiple process control modes and can meet the process testing requirements of different manufacturers. Compared with the related art in which one process model is equipped with a set of frequency converter systems, the equipment cost is greatly reduced and the utilization efficiency of the system is improved.

[0059] In some embodiments, as Figure 2 As shown, the communication switching device includes: a switching control device (not shown in the figure) and a plurality of switches 1202;

[0060] Each of the controllers 110 is connected to a number of switches 1202 corresponding to the number of the frequency conversion devices 130 among the multiple switches 1202; at least two of the switches 1202 corresponding to the controller 110 are connected to the at least two frequency conversion devices 130 in a one-to-one correspondence; the switching control device is connected to the multiple switches 1202 respectively; wherein,

[0061] The switching control device is used to control the working state of the target switch corresponding to the target frequency conversion device to establish a communication connection between the controller and the target frequency conversion device; the target frequency conversion device is determined based on the selection operation for the target control mode.

[0062] In some embodiments, the multiple interfaces of the communication switching device may be interfaces of multiple switches, and may be connected to at least two controllers through the interfaces of the multiple switches.

[0063] In the embodiment of the present application, each controller can be connected to a different frequency conversion device via a different switch, and a switching control device is connected to each controller and each switch. Thus, the switching control device controls the opening and closing of the switch to establish a communication connection between the controller and at least one of the at least two frequency conversion devices.

[0064] Exemplarily, the variable frequency transmission control system includes a switching control device, a first switch, a second switch, a third switch, a fourth switch, a first frequency conversion device, and a second frequency conversion device; wherein, the first switch and the second switch are both connected to the first controller, the first switch is connected to the first frequency conversion device, the second switch is connected to the second frequency conversion device, the third switch and the fourth switch are both connected to the second controller, the third switch is connected to the first frequency conversion device, the fourth switch is connected to the second frequency conversion device, and the switching control device is connected to the first controller, the second controller, the first switch, the second switch, the third switch, and the fourth switch.

[0065] For the first controller, the switching control device controls the first switch to turn on and the second switch to turn off. At this time, the first controller only establishes a communication connection with the first frequency conversion device; the switching control device can also control the second switch to turn on and the first switch to turn off. At this time, the first controller only establishes a communication connection with the second frequency conversion device; the switching control device can also control the first switch and the second switch to turn on. At this time, the first controller establishes a communication connection with the first frequency conversion device and the second frequency conversion device.

[0066] For the second controller, the switching control device controls the third switch to turn on and the fourth switch to turn off, at which time the second controller establishes a communication connection with the first frequency conversion device; the switching control device can also control the fourth switch to turn on and the third switch to turn off, at which time the second controller establishes a communication connection with the second frequency conversion device; the switching control device can also control the third switch and the fourth switch to turn on, at which time the second controller establishes a communication connection with the first frequency conversion device and the second frequency conversion device.

[0067] In some embodiments, when the first switch and the second switch are both connected to the first controller, and the third switch and the fourth switch are not connected to the controller, the switching control device can control the first switch to be turned on and the second switch to be turned off, and at this time the first frequency conversion device establishes a communication connection with the first controller; when the first controller performs a process test through the first frequency conversion device, the second controller can be connected to the third switch and the fourth switch, and then the switching control device can control the fourth switch to be turned on and the third switch to be turned off, and at this time the second frequency conversion device establishes a communication connection with the second controller, so that the second controller can perform a process test through the second frequency conversion device while the first controller performs a process test.

[0068] In an embodiment of the present application, the variable frequency transmission control system includes a human-computer interaction interface corresponding to the switching control device, and the human-computer interaction interface includes controls for multiple control modes. When the control corresponding to the target control mode is triggered, a selection operation can be generated, thereby determining the target frequency conversion device in response to the selection operation for the target control mode.

[0069] In the embodiments of the present application, a switching control device controls the on and off of at least one switch, thereby enabling each controller to establish a communication connection with at least one of the at least two frequency conversion devices. This improves the flexibility of establishing communication connections between the controllers and the frequency conversion devices. Furthermore, compared to the controller itself controlling the on and off of the switch, using a dedicated switching control device to control the on and off of the switch can improve the stability of the communication between the controller and the frequency conversion device.

[0070] In some embodiments, as Figure 3 As shown, the multiple switches 1202 are respectively connected to a power source (not shown in the figure) through their respective corresponding switch components 12021; the switching control device 1201 is connected to the control end of the switch component 12021 corresponding to each of the switches 1201; wherein,

[0071] The switching control device 1201 is used to control the switch component 12021 corresponding to the target switch to be closed, and control the switch components 12021 corresponding to other switches to be opened, so as to establish a communication connection between the controller 110 and the target frequency conversion device;

[0072] The target switch is the switch 1202 connected to the target frequency conversion device among the at least two switches 1202 connected to the controller 110 ; and the other switches are the switches other than the target switch among the at least two switches 1202 connected to the controller 110 .

[0073] In the embodiment of the present application, each switch is connected to a power source via a switch assembly, and a control terminal of the switch assembly is connected to a switching control device. After the switching controller determines a target frequency converter device with which to establish a communication connection, it closes the switch assembly corresponding to the target frequency converter device. This connects the switch to power, thereby establishing a communication connection between the controller and the corresponding frequency converter device via the switch.

[0074] In the embodiment of the present application, while the switching control device controls the switch component corresponding to the target switch to be closed, it also needs to disconnect the switch components corresponding to other switches. In this way, interference to the target switch caused by the activation of other switches can be reduced.

[0075] In some embodiments, the communication switching device further includes a main switch, the number of which is equal to the number of the frequency conversion devices, at least two main switches being connected to at least two frequency conversion devices in a one-to-one correspondence, and each main switch being connected to a corresponding switch. The corresponding switch refers to the switch, among the at least two switches corresponding to each controller, that is connected to the same frequency conversion device as the main switch.

[0076] Exemplarily, the variable frequency transmission control system includes a first switch, a second switch, a third switch, a fourth switch, a first frequency conversion device, a second frequency conversion device, a first main switch, and a second main switch; wherein, if the first controller is connected to the first switch and the second switch, the first switch is connected to the first frequency conversion device, the second switch is connected to the second frequency conversion device, the second controller is connected to the third switch and the fourth switch, the third switch is connected to the first frequency conversion device, the fourth switch is connected to the second frequency conversion device, the first main switch is connected to the first frequency conversion device, and the second main switch is connected to the second frequency conversion device, then the first switch and the third switch are connected to the first frequency conversion device through the first main switch, and the second switch and the fourth switch are connected to the second frequency conversion device through the second main switch.

[0077] In this embodiment of the present application, the switching control device can control whether each switch can be powered on, thereby establishing a communication connection between the controller and the frequency converter. Thus, by determining whether a switch can be powered on, the communication connection between the controller and the frequency converter is established. Switches corresponding to frequency converters not in communication with the controller can be placed in an inoperative state, thereby reducing interference with the target switch caused by the activation of other switches.

[0078] In some embodiments, as Figure 4 As shown, each state switching device includes a motor switching device 1401; each motor switching device includes at least two circuit breakers 14011; each circuit breaker 14011 is connected to the output end of the frequency conversion device; each circuit breaker is connected to the switching control device; wherein,

[0079] Each of the circuit breakers 14011 is used to connect the motor 201 in the motor assembly;

[0080] The switching control device 1201 is used to control the target circuit breaker corresponding to the target motor in the target motor assembly to close, so that the target motor is in a running state; the target motor is determined based on the selection operation for the target control mode.

[0081] In this embodiment of the present application, the number of circuit breakers is equal to the number of motor assemblies. Each circuit breaker is connected to a motor in a motor assembly to control the motor's startup and shutdown. Furthermore, the output terminal of each frequency converter is connected to at least two circuit breakers. In other words, the power output destination of each frequency converter can be determined by at least two motors via at least two circuit breakers.

[0082] In this embodiment of the present application, when the inverter has only one power output path, the switching control device controls the closing of the target circuit breaker corresponding to the target motor while also controlling the opening of other circuit breakers connected to the same inverter as the closed circuit breaker. In other words, the inverter can only output power to one motor, so it is necessary to control the opening of other circuit breakers connected to the same inverter as the closed circuit breaker while simultaneously controlling the closing of the target circuit breaker.

[0083] In some embodiments, when the frequency converter has at least two power output paths, the switching control device may control the target circuit breaker corresponding to the target motor to be closed.

[0084] Exemplarily, a variable frequency drive control system includes a first frequency converter and a second frequency converter. The first frequency converter is connected to a first circuit breaker and a second circuit breaker, and the second frequency converter is connected to a third circuit breaker and a fourth circuit breaker. The first circuit breaker is connected to a first motor, the second circuit breaker is connected to a second motor, the third circuit breaker is connected to a third motor, and the fourth circuit breaker is connected to a fourth motor. The first and second circuit breakers are connected to the same frequency converter, and the third and fourth circuit breakers are connected to the same frequency converter.

[0085] For the first frequency conversion device, when the electric energy output object of the first frequency conversion device is the first motor (that is, the first frequency conversion device is the target frequency conversion device, and the first motor is the target motor in the target motor assembly), the first circuit breaker needs to be closed, or the first circuit breaker needs to be closed and the second circuit breaker needs to be opened; when the electric energy output object of the first frequency conversion device is the second motor (that is, the first frequency conversion device is the target frequency conversion device, and the second motor is the target motor in the target motor assembly), the second circuit breaker needs to be closed, or the second circuit breaker needs to be closed and the first circuit breaker needs to be opened.

[0086] For the second frequency conversion device, when the power output object of the second frequency conversion device is the third motor (that is, the second frequency conversion device is the target frequency conversion device, and the third motor is the target motor in the target motor assembly), the third circuit breaker needs to be closed, or the third circuit breaker needs to be closed and the fourth circuit breaker needs to be disconnected; when the power output object of the second frequency conversion device is the fourth motor (that is, the second frequency conversion device is the target frequency conversion device, and the fourth motor is the target motor in the target motor assembly), the fourth circuit breaker needs to be closed, or the fourth circuit breaker needs to be closed and the third circuit breaker needs to be disconnected.

[0087] In an embodiment of the present application, the switching control device can determine a target motor in the target motor assembly in response to a selection operation for a target control mode. That is, when a target control mode selection operation is generated, a target frequency conversion device corresponding to the target control mode and a target motor for the target frequency conversion device to transmit power to can be determined.

[0088] In the embodiment of the present application, the motor in each motor assembly is connected to the output terminal of the frequency converter via a circuit breaker. Thus, by controlling the on and off of the circuit breaker, the power output destination of the frequency converter can be determined, thereby increasing the flexibility of the frequency converter in switching the power output destination.

[0089] In some embodiments, the switching control device is used to obtain the operating state of the target frequency conversion device; the operating state includes at least a first operating state of the inverter unit of the target frequency conversion device and a second operating state of the rectifier unit of the target frequency conversion device;

[0090] The switching control device is used to control the target circuit breaker corresponding to the target motor to close when the first operating state indicates that the inverter unit stops operating and the second operating state indicates that the rectifier unit of the target frequency conversion device is in a disconnected state.

[0091] In the embodiment of the present application, the control unit of each frequency conversion device can send the operating status of the frequency conversion device to the switching control device, so that the switching control device can obtain the operating status of the target frequency conversion device.

[0092] In an embodiment of the present application, each frequency converter includes a control unit, and the control unit of the frequency converter is required to transmit its own operating status to the switching control device. The operating status of the frequency converter includes at least a first operating status of the inverter unit of the frequency converter and a second operating status of the rectifier unit of the frequency converter. The first operating status of the inverter unit may indicate whether the inverter unit has stopped operating, and the second operating status of the rectifier unit indicates whether the rectifier unit is disconnected.

[0093] When the first operating state indicates that the inverter unit stops operating and the second operating state indicates that the rectifier unit of the frequency converter is in a disconnected state, the switching control device controls the circuit breaker corresponding to the target motor to close, or controls the circuit breaker corresponding to the target motor to close and other circuit breakers connected to the same frequency converter as the closed circuit breaker to disconnect.

[0094] It is understood that the transformer of the frequency converter is connected to the power grid and is used to step down the AC power output from the power grid. The rectifier unit of the frequency converter is connected to the transformer and is used to rectify the stepped-down AC power to generate DC power. The inverter unit of the frequency converter is connected to the rectifier unit of the frequency converter and is used to convert DC power into DC power. The inverter unit of the frequency converter outputs AC power to the motor. Therefore, when switching the power output destination of the frequency converter, it must be performed with the power supply disconnected. Therefore, the controller needs to determine whether the power output destination can be switched based on the current state of the frequency converter.

[0095] In an embodiment of the present application, the control unit of each frequency converter can send the first operating state of the inverter unit of the frequency converter and the second operating state of the rectifier unit of the frequency converter to the switching control device. When the switching control device determines that the first operating state indicates that the inverter unit has stopped operating and the second operating state indicates that the rectifier unit of the frequency converter is in the disconnected state, the target circuit breaker corresponding to the target motor is controlled to close. In this way, the power output target of the frequency converter can be switched when the frequency converter is not outputting power, thereby improving safety.

[0096] In some embodiments, as Figure 5 As shown, each of the state switching devices includes a coding switching device 1402; each of the coding switching devices 1402 is connected to the corresponding frequency conversion device 130; each of the coding switching devices 1402 is used to connect to the encoder 202 in the motor assembly; each of the coding switching devices 1402 is used to send the encoder signal of the target encoder corresponding to the target motor to the frequency conversion device 130 connected to the target encoder.

[0097] In the embodiments of the present application, each motor assembly includes a motor and an encoder for acquiring motor parameters. Therefore, after switching the output of the frequency converter, the corresponding encoder also needs to be switched. For example, the motor parameter may be a speed parameter of the motor.

[0098] In an embodiment of the present application, each encoding switching device is connected to at least two encoders, and each encoder sends the encoder signal of its corresponding target motor to the encoding switching device, thereby completing the encoder switching. The encoder signal can be a motor parameter. When the motor switching device corresponding to the encoding switching device switches the target motor, the encoding switching device can send the encoder signal of the target encoder corresponding to the target motor to the frequency conversion device connected to the target encoder.

[0099] Exemplarily, the variable frequency drive control system includes a first frequency conversion device and a second frequency conversion device. The first frequency conversion device is connected to a first encoding switching device and a first motor switching device, and the second frequency conversion device is connected to a third encoding switching device and a fourth motor switching device. The first encoding switching device is connected to a first encoder and a second encoder, the first motor switching device is connected to a first motor and a second motor, the second encoding switching device is connected to a third encoder and a fourth encoder, and the second motor switching device is connected to a third motor and a fourth motor. The first encoder is connected to the first motor for collecting parameters of the first motor, the second encoder is connected to the second motor for collecting parameters of the second motor, the third encoder is connected to the third motor for collecting parameters of the third motor, and the fourth encoder is connected to the fourth motor for collecting parameters of the fourth motor.

[0100] When the controller establishes a communication connection with the first frequency conversion device and the first frequency conversion device outputs power to the first motor, the first encoder switching device connected to the first motor sends the encoder signal of the first encoder to the first frequency conversion device, thereby completing the encoder switching.

[0101] When the controller establishes a communication connection with the second frequency conversion device and the power output target of the second frequency conversion device is the third motor, the third encoder switching device connected to the third motor sends the encoder signal of the third encoder to the third frequency conversion device, thereby completing the encoder switching.

[0102] When the controller establishes communication connections with the first and second frequency conversion devices, and the second frequency conversion device outputs power to the fourth motor, and the first frequency conversion device outputs power to the second motor, the second encoding switching device connected to the second motor transmits the encoder signal of the second encoder to the second frequency conversion device, while the fourth encoding switching device connected to the fourth motor transmits the encoder signal of the fourth encoder to the fourth frequency conversion device, thereby completing the encoder switching.

[0103] In an embodiment of the present application, each state switching device includes an encoding switching device; each encoding switching device is connected to a corresponding frequency conversion device; and each encoding switching device is configured to transmit an encoder signal from a target encoder corresponding to a target motor to the frequency conversion device connected thereto. Thus, the encoding switching device can simultaneously transmit an encoder signal from an encoder corresponding to the switched motor to the frequency conversion device, thereby completing encoder switching and effectively switching the motor.

[0104] In some embodiments, the switching control device is further configured to generate a switching control signal corresponding to a target encoder in the target motor assembly, and send the switching control signal to an encoding switching device corresponding to the target encoder; the target encoder is determined based on a selection operation for a target control mode;

[0105] The encoding switching device is used to send the encoder signal of the target encoder to the frequency conversion device connected to the target encoder based on the switching control signal.

[0106] In an embodiment of the present application, the switching control device can generate a switching control signal corresponding to the target encoder in the target motor assembly when the first operating state indicates that the inverter unit stops operating and the second operating state indicates that the rectifier unit of the frequency conversion device is in a disconnected state.

[0107] In an embodiment of the present application, the switching control device can determine a target encoder in a target motor assembly in response to a target control mode selection operation. Specifically, when a target control mode selection operation is generated, the switching control device can determine a target frequency conversion device corresponding to the target control mode, a target motor to which the target frequency conversion device transmits power, and a target frequency conversion device for collecting motor parameters of the target motor in operation.

[0108] In an embodiment of the present application, the switching control device may generate a switching control signal corresponding to the target encoder and transmit the switching control signal to the target frequency conversion device corresponding to the target encoder. The switching control device may store a correspondence between different encoders corresponding to the frequency conversion device and the switching control signals. After determining that the encoder being switched is the target encoder, the switching control device may determine the switching control signal corresponding to the target encoder based on the target encoder in the above correspondence.

[0109] Exemplarily, the variable frequency drive control system includes a first frequency conversion device and a second frequency conversion device. The first frequency conversion device is connected to a first encoding switching device and a first motor switching device, and the second frequency conversion device is connected to a third encoding switching device and a fourth motor switching device. The first encoding switching device is connected to a first encoder and a second encoder, the first motor switching device is connected to a first motor and a second motor, the second encoding switching device is connected to a third encoder and a fourth encoder, and the second motor switching device is connected to a third motor and a fourth motor. The first encoder is connected to the first motor for collecting parameters of the first motor, the second encoder is connected to the second motor for collecting parameters of the second motor, the third encoder is connected to the third motor for collecting parameters of the third motor, and the fourth encoder is connected to the fourth motor for collecting parameters of the fourth motor.

[0110] Among them, the switching control device includes a correspondence between the first encoder corresponding to the low-level signal and the second encoder corresponding to the high-level signal. When the controller establishes a communication connection with the first frequency conversion device and the power output object of the first frequency conversion device is the first motor, the switching control device generates a low-level signal based on the above-mentioned correspondence and sends the low-level signal to the first encoding switching device. The first encoding switching device is used to send the encoder signal of the first encoder to the first frequency conversion device based on the low-level signal.

[0111] The switching control device includes a correspondence between the third encoder corresponding to the low-level signal and the fourth encoder corresponding to the high-level signal. When the controller establishes a communication connection with the second frequency conversion device and the power output object of the second frequency conversion device is the third motor, the switching control device generates a low-level signal based on the above correspondence and sends the low-level signal to the second encoding switching device. The second encoding switching device is used to send the encoder signal of the third encoder to the second frequency conversion device based on the low-level signal.

[0112] It should be noted that the switching control device stores the correspondence between different encoders and switching control signals according to the frequency conversion device. Therefore, after determining the target frequency conversion device connected to the controller for communication, it is necessary to obtain the corresponding multiple correspondences based on the frequency conversion device connected to the controller for communication, and then determine the corresponding switching control signal.

[0113] In an embodiment of the present application, a switching control device is configured to generate a switching control signal corresponding to a target encoder and transmit the switching control signal to an encoding switching device corresponding to the target encoder; and an encoding switching device is configured to transmit an encoder signal of the target encoder to a frequency converter connected to the target encoder based on the switching control signal. This allows the encoder to be switched simultaneously with the motor, thereby improving the efficiency of switching motor components. Furthermore, switching the encoder by using a switching control signal corresponding to the target encoder can improve the accuracy of encoder switching.

[0114] The embodiment of the present application also provides a control method based on a variable frequency transmission control system, which can be applied to a communication switching device of a variable frequency transmission control system, such as Figure 6 As shown, the power adjustment method can be implemented through steps S601 and S602:

[0115] Step S601: establishing a communication connection between the controller and a target frequency conversion device.

[0116] Wherein, the target frequency conversion device is at least one frequency conversion device among the at least two frequency conversion devices connected to the communication switching device;

[0117] In the embodiment of the present application, each controller in the variable frequency transmission control system can establish a communication connection with at least one of the at least two frequency conversion devices through the communication switching device.

[0118] Step S602 : controlling the working state of the state switching device so that a target motor component among the at least two motor components is in a running state.

[0119] Wherein, the target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

[0120] In some embodiments, the above step S601 may be implemented by step S6011:

[0121] Step S6011: Control the working state of the target switch corresponding to the target frequency conversion device by switching the control device to establish a communication connection between the controller and the target frequency conversion device.

[0122] In some embodiments, the above step S6011 may be implemented by step S60111:

[0123] Step S60111: Control the switch component corresponding to the target switch to be closed and control the switch components corresponding to other switches to be opened through the switching control device, so as to establish a communication connection between the controller and the target frequency conversion device.

[0124] The target switch is the switch connected to the target frequency conversion device among the at least two switches connected to the controller; and the other switches are the switches other than the target switch among the at least two switches connected to the controller.

[0125] In some embodiments, the above step S602 may be implemented by step S6021:

[0126] Step S6021: Control the target circuit breaker corresponding to the target motor in the target motor assembly to be closed by switching the control device, so that the target motor is in a running state.

[0127] The target motor is determined based on a selection operation for a target control mode.

[0128] In some embodiments, the above method may also be implemented through step S603, and the above step S6021 may be implemented through step S60211:

[0129] Step S603: Obtain the operating state of the target frequency conversion device through the switching control device; the operating state at least includes a first operating state of the inverter unit of the target frequency conversion device and a second operating state of the rectifier unit of the target frequency conversion device.

[0130] Step S60211, when the first operating state indicates that the inverter unit stops operating, and the second operating state indicates that the rectifier unit of the target frequency conversion device is in a disconnected state, the target circuit breaker corresponding to the target motor is controlled to be closed through the switching control device.

[0131] In some embodiments, the above method may also be implemented through step S604:

[0132] Step S604 : generating a switching control signal corresponding to the target encoder in the target motor assembly through the switching control device, and sending the switching control signal to the encoding switching device corresponding to the target encoder.

[0133] The target encoder is determined based on a selection operation for a target control mode; and the encoding switching device is configured to send an encoder signal of the target encoder to the target frequency conversion device based on the switching control signal.

[0134] The following describes the application of the embodiment of the present application in a practical process:

[0135] Medium-voltage main drive control systems for large motors are widely used in automotive testing systems, large-scale new energy testing systems, and large metallurgical rolling mill systems. Medium-voltage AC / DC variable-frequency speed control systems are widely used for the main drive control systems of these large-scale equipment due to their high dynamic performance, control accuracy, efficient energy feedback, and energy-saving technologies. However, due to diverse needs, the cost of a single system is prohibitive for small and medium-sized enterprises. Furthermore, some equipment is inefficiently utilized, resulting in wasted resources.

[0136] The embodiment of the present application provides a control system for a multi-motor common medium-voltage variable-frequency main drive, which solves the problem of resource waste caused by low utilization of existing equipment, while lowering the threshold for small and medium-sized enterprises and laboratories, and promoting rapid development of the industry.

[0137] The control system of the multi-motor common medium-voltage variable-frequency main drive in the embodiment of the present application utilizes two independent medium-voltage variable-frequency main drives (the frequency conversion devices in the above embodiment) to complete the control of four main motors (the motors in the above embodiment) by three sets of model controllers through remote switching of power and control signals, wherein any set of model control can control any one or more motors.

[0138] like Figure 7 As shown, the control system of the multi-motor common medium-voltage variable frequency main drive includes a first controller 1, a second controller 2, and a third controller 3 (controllers in the above embodiment), a PN communication switching system 4 (communication switching device in the above embodiment), a first medium-voltage frequency converter system MV1, a second medium-voltage frequency converter system MV2 (frequency converter in the above embodiment), a first encoder signal switching system 5 (encoder switching device in the above embodiment), a first power switching system 6 (motor switching device in the above embodiment), a second encoder signal switching system 7, a second power switching system 8, a first motor encoder 9 (encoder in the above embodiment), a second motor encoder 10, a third motor encoder 11, a fourth motor encoder 12, a first motor M1, a second motor M2, a third motor M3, and a fourth motor M4 (motor in the above embodiment);

[0139] The first controller 1, the second controller 2 and the third controller 3 are respectively connected to the PN communication switching system 4; the PN communication switching system 4 is respectively connected to the first medium voltage inverter system MV1 and the second medium voltage inverter system MV2; the first medium voltage inverter system MV1 is respectively connected to the first encoder signal switching system 5 and the first power switching system 6; the second medium voltage inverter system MV2 is respectively connected to the second encoder signal switching system 7 and the second power switching system 8; the first encoder signal switching system 5 is connected to the first motor encoder 9 and the second motor encoder 10, the first power switching system 6 is connected to the first motor M1 and the second motor M2, the first motor encoder 9 is connected to the first motor M1, and the second motor encoder 10 is connected to the second motor M2; the second encoder signal switching system 7 is connected to the third motor encoder 11 and the fourth motor encoder 12, the second power switching system 8 is connected to the third motor M3 and the fourth motor M4, the third motor encoder 11 is connected to the third motor M3, and the fourth motor encoder 12 is connected to the fourth motor M4.

[0140] In the embodiments of this application, the first, second, and third controllers are primarily responsible for functional model calculation and logic control. They can be a variety of different PLC controllers. This system supports three types of PLC controllers, each capable of independently completing its own control tasks. Any of these controllers can be combined to control one or two medium-voltage inverter systems to accomplish complex and diverse control tasks.

[0141] In the embodiment of the present application, the PN communication switching system mainly realizes the communication switching between the main transmission system and the PLC control system. Figure 8 As shown, the PN communication switching system includes a first switch 41, a second switch 42, a third switch 43, a fourth switch 44, a fifth switch 45, a sixth switch 46, a seventh switch 47, an eighth switch 48, and a switching system 49. The switching system 49 may be a PLC.

[0142] The first controller 1 is connected to a first switch 41 and a second switch 42, respectively; the second controller 2 is connected to a third switch 43 and a fourth switch 44, respectively; the third controller 3 is connected to a fifth switch 45 and a sixth switch 46, respectively; the first switch 41, the third switch 43, and the fifth switch 45 are connected via a seventh switch 47, which is connected to the first medium-voltage inverter system MV1; the second switch 42, the fourth switch 44, and the sixth switch 46 are connected via an eighth switch 48, which is connected to the second medium-voltage inverter system MV2; and the switching system 49 is connected to the first controller 1, the second controller 2, the third controller 3, the first switch 41, the second switch 42, the third switch 43, the fourth switch 44, the fifth switch 45, and the sixth switch 46. The switches may be PROFINET Isochronous Real-Time (IRT) switches.

[0143] In the embodiment of the present application, the switching circuit of the first controller 1 is composed of a first switch 41 and a second switch 42, and is connected to a switching system 49 to control the on and off of the switch and the 24V power supply to control the PN switching;

[0144] When the first switch 41 is on and the second switch 42 is off, the first controller 1 controls the first medium voltage inverter system MV1 ; when the first switch 41 is off and the second switch 42 is on, the first controller 1 controls the second medium voltage inverter system MV2 .

[0145] Similarly, the switching system 49 controls the 24V power supplies of the third switch 43 , the fourth switch 44 , the fifth switch 45 , and the sixth switch 46 to enable the second controller 2 and the third controller 3 to control MV1 and MV2 respectively.

[0146] like Figure 7 and Figure 9 As shown, the first medium voltage inverter system MV1 and the second medium voltage inverter system MV2 each include a transformer 13, a rectifier unit 14, an inverter unit 15 and a control unit 16;

[0147] Transformer 13 is used to connect to the power grid and provide a power source for the entire system. The medium-voltage inverter system mainly adopts the new high-power device Integrated Gate-Commutated Thyristor (IGCT), and is based on the mid-point clamped three-level voltage source AC-DC-AC technology and vector control technology. The rectifier circuit adopts PWM rectification. The DC bus voltage is controlled through PWM modulation rectification control, and the grid-side power factor can be controlled between -1 and 1. The inverter unit adopts the motor vector control strategy and voltage-type PWM control strategy to control the various IGCT switching devices of the mid-point clamped three-level inverter, so that the output voltage and current frequency are variable, achieving high-performance operation of the motor.

[0148] like Figure 10 As shown, the first power switching system 6 includes a first circuit breaker Q1 and a second circuit breaker Q2, and the second power switching system 8 includes a third circuit breaker Q3 and a fourth circuit breaker Q4. The first circuit breaker Q1 is connected to the first motor M1, the second circuit breaker Q2 is connected to the second motor M2, the third circuit breaker Q3 is connected to the third motor M3, and the fourth circuit breaker Q4 is connected to the fourth motor M4. The first circuit breaker Q1, the second circuit breaker Q2, the third circuit breaker Q3, and the fourth circuit breaker Q4 are all in communication with the switching system 49.

[0149] In an embodiment of the present application, in a power switching system, each group of medium-voltage inverter systems is equipped with a power switching cabinet, and each power switching cabinet is composed of two circuit breakers (for example, the first medium-voltage inverter system MV1 includes Q1 and Q2, and the second medium-voltage inverter system MV2 includes Q3 and Q4). The two circuit breakers of each power switching cabinet share a mechanical lock to ensure that only one circuit breaker can be closed to ensure system safety. The closing and opening of the circuit breakers of each switching cabinet are controlled by the switching system PLC.

[0150] In some embodiments, as Figure 11 As shown, the switching process of the first power switching system can be implemented through steps S1101 to S1109:

[0151] Step S1101, determining whether the inverter side of the inverter is running.

[0152] When the inverter side of the frequency converter is running, the "inverter side shutdown process" is executed; when the inverter side of the frequency converter is not running, step S1102 is executed.

[0153] In the embodiment of the present application, the inverter refers to a first medium voltage inverter system MV1 connected to the first power switching system.

[0154] Step S1102, determining whether the rectifier side of the inverter is closed.

[0155] When the rectifier side of the frequency converter is closed, the “rectifier side opening process” is executed; when the inverter side of the frequency converter is not closed, step S1103 is executed.

[0156] Step S1103: motor selection.

[0157] When the first motor M1 is selected, step S1104 is executed; when the second motor M2 is selected, step S1107 is executed.

[0158] Step S1104: determine whether the second circuit breaker Q2 is closed.

[0159] When the second circuit breaker Q2 is closed, the “Q2 opening operation” is performed; when the second circuit breaker Q2 is not closed, step S1105 is performed.

[0160] Step S1105 , determining whether the first circuit breaker Q1 is closed.

[0161] When the first circuit breaker Q1 is closed, step S1106 is executed; when the first circuit breaker Q1 is not closed, the “Q1 closing operation” is executed.

[0162] Step S1106, select the M1 encoder.

[0163] In the embodiment of the present application, the M1 encoder is the first motor encoder.

[0164] Step S1107, determining whether the first circuit breaker Q1 is closed.

[0165] When the first circuit breaker Q1 is closed, the “Q1 opening operation” is performed; when the first circuit breaker Q1 is not closed, step S1108 is performed.

[0166] Step S1108: Determine whether the second circuit breaker Q2 is closed.

[0167] When the second circuit breaker Q2 is closed, step S1109 is executed; when the second circuit breaker Q2 is not closed, the “Q2 closing operation” is executed.

[0168] Step S1109, select the M2 encoder.

[0169] In the embodiment of the present application, the M2 encoder is the second motor encoder.

[0170] In some embodiments, as Figure 12 As shown, the switching process of the second power switching system can be implemented through steps S1201 to S1209:

[0171] Step S1201, determining whether the inverter side of the inverter is running.

[0172] When the inverter side of the frequency converter is running, the "inverter side shutdown process" is executed; when the inverter side of the frequency converter is not running, step S1202 is executed.

[0173] In the embodiment of the present application, the inverter refers to a second medium voltage inverter system MV2 connected to the second power switching system.

[0174] Step S1202, determining whether the rectifier side of the inverter is closed.

[0175] When the rectifier side of the inverter is closed, execute the "rectifier side opening process", and when the inverter side of the inverter is not closed, execute step S1203.

[0176] Step S1203: motor selection.

[0177] When the third motor M3 is selected, step S1204 is executed; when the fourth motor M4 is selected, step S1207 is executed.

[0178] Step S1204: determine whether the fourth circuit breaker Q4 is closed.

[0179] When the fourth circuit breaker Q4 is closed, the “Q4 opening operation” is performed; when the fourth circuit breaker Q4 is not closed, step S1205 is performed.

[0180] Step S1205: Determine whether the third circuit breaker Q3 is closed.

[0181] When the third circuit breaker Q3 is closed, step S1206 is executed; when the third circuit breaker Q3 is not closed, the “Q3 closing operation” is executed.

[0182] Step S1206, select the M3 encoder.

[0183] In the embodiment of the present application, the M3 encoder is the third motor encoder.

[0184] Step S1207, determining whether the third circuit breaker Q3 is closed.

[0185] When the third circuit breaker Q3 is closed, the “Q3 opening operation” is performed; when the third circuit breaker Q3 is not closed, step S1208 is performed.

[0186] Step S1208: Determine whether the fourth circuit breaker Q4 is closed.

[0187] When the fourth circuit breaker Q4 is closed, step S1209 is executed; when the fourth circuit breaker Q4 is not closed, the “Q4 closing operation” is executed.

[0188] Step S1209, select the M4 encoder.

[0189] In the embodiment of the present application, the M4 encoder is the fourth motor encoder.

[0190] In some embodiments, the first encoder signal switching system corresponds to the first medium voltage inverter system, which is used to switch the speed encoder signals of the first motor and the second motor, and the second encoder signal switching system corresponds to the second medium voltage inverter system, which is used to switch the speed encoder signals of the third motor and the fourth motor.

[0191] like Figure 13 As shown, when the controller needs to control the first motor, the switching system sends the control signal to the encoder signal switching system; when the control signal of the encoder signal switching system is control 1 = low (low-level signal), the switch S1 dial switch connects to the IN1 channel, and the encoder signal switching system outputs out1 to the first medium-voltage inverter system as the motor encoder signal of the first motor M1.

[0192] When the controller needs to control the second motor, the switching system generates a control signal and sends it to the encoder signal switching system. When the control signal "control 1" is High (a high-level signal), the encoder signal switching system switches S2 to the IN2 channel. The encoder signal switching system then outputs "out2," the motor encoder signal for the second motor M2, to the first medium-voltage inverter system. Similarly, the motor speed encoder signals for the third and fourth motors are switched.

[0193] In some embodiments, the operation process of the control system of the multi-motor common medium voltage variable frequency main drive includes the following steps:

[0194] Step 1: The controller sends a remote enable signal to the switching system.

[0195] Step 2: The switching system automatically completes PN communication switching according to demand, and the controller establishes normal communication with the medium voltage inverter system.

[0196] Step 3: The controller reads the operating status of the medium voltage inverter system and completes the motor selection switching according to the power switching system operation.

[0197] Step 4: The controller sends an encoder switching instruction to the encoder signal switching system to complete the encoder selection.

[0198] Step 5: After the power switching system and the encoder switching system receive the control command from the controller, the power system and the encoder signal are automatically switched.

[0199] At this point, the remote operation switch is completed and the controller can work normally according to the actual working conditions.

[0200] In an embodiment of the present application, three PLC control systems (a first controller 1, a second controller 2, and a third controller 3) are preset as needed in the control system of the entire multi-motor common medium-voltage variable-frequency main drive, and each controller is preset with three medium-voltage inverter system control modes: individual control of MV1, individual control of MV2, and simultaneous control of MV1 and MV2.

[0201] The MV1 medium-voltage inverter system comes with two preset motor parameter sets: M1 and M2. The MV2 medium-voltage inverter system comes with two preset motor parameter sets: M3 and M4. These combinations enable a total of 36 process control modes. One-touch switching between control programs and parameters on the central control console makes operation even more convenient and efficient.

[0202] Compared with a process model equipped with a set of medium-voltage inverter systems, the system in this application greatly reduces equipment costs and improves equipment utilization efficiency.

[0203] The following describes the application of the variable frequency drive control system in the embodiment of the present application in actual scenarios:

[0204] Scenario 1: When the variable frequency drive control system is applied to a high acceleration test scenario, tire test manufacturer A needs to simulate the use of tires with different wheels under high acceleration conditions. Figure 7 As shown in the figure, tire test manufacturer A can use the M1 motor in the variable frequency drive control system to carry the A hub drum load, and use the M2 motor to carry the B hub drum load. The A hub drum load and the B hub drum load are the equipment to be tested by tire test manufacturer A.

[0205] In scenario 1, a host control system (such as one of the first controllers 1 to 3) is required. The host control system can be the controller in the variable frequency drive control system or the manufacturer's own controller. A medium voltage MV1 system (such as the first medium voltage inverter system MV1 or the second medium voltage inverter system MV2) and two motors of different powers can complete the testing of two or even multiple products.

[0206] In addition, when tire testing manufacturer A has not completed the test, tire testing manufacturer B does not need to conduct the test after tire testing manufacturer A. The test can be conducted through the upper computer control system, medium voltage MV2 system, M3 motor and M4 motor other than manufacturer A.

[0207] Scenario 2: When the variable frequency drive control system is applied to the wind power new energy gearbox test scenario, the new energy gearbox test system requires at least one host control system (such as one of the first controllers 1 to 3), two MV systems (the first medium voltage inverter system MV1 and the second medium voltage inverter system MV2), and two motors (M1 and M2) to complete the gearbox drag test.

[0208] For example, through the first controller 2, the first medium-voltage inverter system MV1 and motor M1 carry gear A, while the second medium-voltage inverter system MV2 and motor M3 carry gear B as the load for gear A, completing the towing test. Since wind power gearboxes come in a wide variety of sizes, multiple switching groups can effectively reduce test system costs.

[0209] Scenario 3: When variable frequency drive control systems are applied to metallurgical transformation scenarios, metallurgical systems often face the problem of upgrading and transforming the upper computer automation system. Drawing on the switching solution of the variable frequency drive control system, a PN communication switching system is implanted in the original customer system to meet the requirements of smooth switching between two different PLC upper computer control systems (the original PLC system and the new PLC system).

[0210] For example, the original host computer system A may be unable to meet stable production requirements under the new process due to a shortage of spare parts. Therefore, it needs to be replaced with a new PLC system B. Due to the long programming and processing time, the factory cannot completely shut down production to replace PLC system B. The PN communication switching system allows the original PLC system to continue production during normal production to meet daily order requirements. During shutdowns for maintenance or when orders are not fully booked, the new PLC system B can be switched to for debugging until PLC system B is fully debugged.

[0211] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned steps / processes does not mean the order of execution, and the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The above-mentioned serial numbers of the embodiments of the present application are for description only and do not represent the advantages and disadvantages of the embodiments.

[0212] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0213] The above are only implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the protection scope of the present application.

Claims

1. A variable frequency drive control system, characterized in that: The variable frequency transmission control system includes a communication switching device, at least two frequency conversion devices, and at least two state switching devices; The communication switching device is connected to the at least two frequency conversion devices; the at least two frequency conversion devices are connected to the at least two state switching devices in a one-to-one correspondence; the communication switching device is also connected to the at least two state switching devices; wherein, The communication switching device is used to connect at least two controllers; each of the state switching devices is used to connect at least two motor assemblies; The communication switching device is used to establish a communication connection between the controller and a target frequency conversion device; the target frequency conversion device is at least one frequency conversion device among the at least two frequency conversion devices; The communication switching device is further used to control the working state of the state switching device so that the target motor component of the at least two motor components is in the running state; The target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

2. The variable frequency drive control system according to claim 1, characterized in that: The communication switching device includes: a switching control device and a plurality of switches; Each of the controllers is connected to a number of switches corresponding to the number of the frequency conversion devices among the multiple switches; at least two switches corresponding to the controller are connected to the at least two frequency conversion devices in a one-to-one correspondence; the switching control device is connected to the multiple switches respectively; wherein, The switching control device is used to control the working state of the target switch corresponding to the target frequency conversion device to establish a communication connection between the controller and the target frequency conversion device; the target frequency conversion device is determined based on the selection operation for the target control mode.

3. The variable frequency drive control system according to claim 2, characterized in that: The multiple switches are connected to the power supply through their respective corresponding switch components; the switching control device is connected to the control end of the switch component corresponding to each of the switches; wherein, The switching control device is used to control the switch component corresponding to the target switch to be closed, and control the switch components corresponding to other switches to be opened, so as to establish a communication connection between the controller and the target frequency conversion device; The target switch is a switch connected to the target frequency conversion device among at least two switches connected to the controller; and the other switches are switches other than the target switch among at least two switches connected to the controller.

4. The variable frequency drive control system according to claim 2, characterized in that: Each of the state switching devices includes a motor switching device; each of the motor switching devices includes at least two circuit breakers; each of the circuit breakers is connected to the output end of the frequency conversion device; each of the circuit breakers is connected to the switching control device; wherein, Each of the circuit breakers is used to connect to the motor in the motor assembly; The switching control device is used to control the target circuit breaker corresponding to the target motor in the target motor assembly to close so that the target motor is in a running state; the target motor is determined based on a selection operation for a target control mode.

5. The variable frequency drive control system according to claim 4, characterized in that: The switching control device is configured to obtain an operating state of the target frequency conversion device; the operating state includes at least a first operating state of the inverter unit of the target frequency conversion device and a second operating state of the rectifier unit of the target frequency conversion device; The switching control device is used to control the target circuit breaker corresponding to the target motor to close when the first operating state indicates that the inverter unit stops operating and the second operating state indicates that the rectifier unit of the target frequency conversion device is in a disconnected state.

6. The variable frequency drive control system according to claim 5, characterized in that: Each of the state switching devices includes a coding switching device; each of the coding switching devices is connected to a corresponding frequency conversion device; Each of the encoding switching devices is used to connect to the encoder in the motor assembly; Each of the encoding switching devices is used to send an encoder signal of a target encoder corresponding to the target motor to a frequency conversion device connected to the target encoder.

7. The variable frequency drive control system according to claim 6, characterized in that: The switching control device is further configured to generate a switching control signal corresponding to a target encoder in the target motor assembly, and send the switching control signal to an encoding switching device corresponding to the target encoder; The target encoder is determined based on a selection operation for a target control mode; The encoding switching device is used to send the encoder signal of the target encoder to the target frequency conversion device based on the switching control signal.

8. A control method based on a variable frequency drive control system, characterized in that: The control method is applied to a communication switching device of a variable frequency transmission control system; the variable frequency transmission control system further comprises at least two frequency conversion devices and at least two state switching devices; the communication switching device is connected to the at least two frequency conversion devices; the at least two frequency conversion devices are connected to the at least two state switching devices in a one-to-one correspondence; The communication switching device is also connected to the at least two state switching devices; the control method includes: Establishing a communication connection between the controller and a target frequency conversion device; the target frequency conversion device is at least one frequency conversion device among the at least two frequency conversion devices connected to the communication switching device; The working state of the state switching device is controlled so that the target motor component among the at least two motor components is in the running state; the target frequency conversion device is used to transmit electric energy to the target motor component in the running state.

9. The control method according to claim 8, characterized in that: The communication switching device includes: a switching control device and a plurality of switches; the establishing of a communication connection between the controller and the target frequency conversion device includes: The switching control device controls the working state of the target switch corresponding to the target frequency conversion device to establish a communication connection between the controller and the target frequency conversion device; the target frequency conversion device is determined based on the selection operation for the target control mode.

10. The control method according to claim 9, characterized in that: The state switching device includes a motor switching device, each of the motor switching devices includes at least two circuit breakers; The controlling the working state of the state switching device so that the target motor component of the at least two motor components is in the running state includes: By switching the control device, controlling the target circuit breaker corresponding to the target motor in the target motor assembly to close, so that the target motor is in a running state; The target motor is determined based on a selection operation for a target control mode.

11. The control method according to claim 10, characterized in that: Each of the state switching devices includes a coding switching device; the method further includes: Generate a switching control signal corresponding to a target encoder in the target motor assembly through the switching control device, and send the switching control signal to an encoding switching device corresponding to the target encoder; The target encoder is determined based on a selection operation for a target control mode; and the encoding switching device is configured to send an encoder signal of the target encoder to the target frequency conversion device based on the switching control signal.

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