Motor control system and motor operation method

Abstract

This application provides a motor control system and motor operation method, including a frequency converter, a power supply data sampling module, and a motor. By deploying the power supply data sampling module, the current data of the motor during operation is collected and sent to the frequency converter. The frequency converter obtains the power information of the motor during operation based on the current data and adjusts the output reactive current according to the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is at a predetermined value, thus solving the problem of low power factor of the motor during power frequency operation in the prior art.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a motor control system and a motor operation method. Background Technology

[0002] Electric motors are widely used in industries such as metallurgy, petrochemicals, power, and mining, with power typically ranging from several thousand kilowatts to tens of thousands of kilowatts. During motor startup, direct starting at the power frequency can cause the starting current to reach 5 to 8 times the motor's rated current. This not only causes a huge impact on the power grid but may also lead to voltage drops, equipment damage, and other problems, posing a threat to power grid stability and equipment safety.

[0003] In existing technologies, motors are typically started using frequency converters (FDs). This involves gradually increasing the motor speed to the mains frequency via the FD to achieve a smooth start. After the soft start is complete, the motor switches to the mains grid, and the FD enters a shutdown or power-off state.

[0004] However, existing solutions result in low power factor for motors operating at industrial frequencies. Summary of the Invention

[0005] The motor control system and motor operation method provided in this application are intended to at least solve the problem of low power factor of motors when running at power frequency in the prior art.

[0006] In a first aspect, embodiments of this application provide a motor control system, comprising: a frequency converter, a power supply data sampling module, and a motor; the input terminal of the frequency converter is connected to the output terminal of the power frequency grid; the input terminal of the motor is connected to the output terminal of the frequency converter and the output terminal of the power frequency grid; the input terminal of the power supply data sampling module is disposed at the input terminal of the motor, and the power supply data sampling module is connected to the frequency converter; the power supply data sampling module is used to collect current data during motor operation and send the current data to the frequency converter; the frequency converter is used to obtain power information of the motor during operation based on the current data, and adjust the output reactive current based on the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is a predetermined power factor value.

[0007] In one possible implementation, the system further includes a first disconnect switch, a second disconnect switch, and a third disconnect switch; the input terminal of the frequency converter is connected to the power grid via the first disconnect switch, and the output terminal of the frequency converter is connected to the input terminal of the motor via the second disconnect switch; the input terminal of the motor is connected to the power grid via the third disconnect switch; wherein, the input terminal of the power supply data sampling module is located between the third disconnect switch and the output terminal of the power grid, and / or between the third disconnect switch and the input terminal of the motor, and / or between the second disconnect switch and the input terminal of the motor.

[0008] In one possible implementation, the number of motors is at least N, where N is an integer greater than or equal to 2; the input terminals of at least NM motors are connected to the output terminal of the frequency converter through corresponding second disconnect switches, and connected to the power grid through corresponding third disconnect switches; wherein, M is a non-negative integer less than or equal to N-1.

[0009] In one possible implementation, the output terminal of the power frequency grid is connected to at least two of the motors via a power supply trunk line and a power supply branch line; the input terminal of the power supply data sampling module is located on the power supply branch line where the third disconnecting switch corresponding to each of the motors is located, and / or, is located on the power supply trunk line.

[0010] In one possible implementation, each of the power supply branches is connected to the power supply trunk through a branch junction point; when the input terminal of the power supply data sampling module is located on the power supply branch where the third disconnecting switch corresponding to each motor is located, the input terminal of the power supply data sampling module is located between each of the third disconnecting switches and the branch junction point, and / or between each of the third disconnecting switches and the input terminal of the motor, and / or between each of the second disconnecting switches and the input terminal of the motor.

[0011] In one possible implementation, the operating modes of the motor control system include at least a soft-start mode, a power factor improvement mode, and a grid-driven mode; when the motor control system is operating in the soft-start mode, the first disconnect switch and the second disconnect switch are closed; when the motor control system is operating in the power factor improvement mode, the first disconnect switch, the second disconnect switch, and the third disconnect switch are closed; when the motor control system is operating in the grid-driven mode, the third disconnect switch is closed.

[0012] In one possible implementation, the power frequency grid includes a first power frequency grid and a second power frequency grid, and the motor control system further includes a voltage sampling module; the input terminal of the frequency converter is connected to the output terminal of the first power frequency grid; the input terminal of the motor is connected to the output terminal of the frequency converter and the output terminal of the second power frequency grid; the input terminal of the voltage sampling module is located at the output terminal of the second power frequency grid, and the voltage sampling module is connected to the frequency converter.

[0013] In one possible implementation, the power factor is predetermined to be 1.0.

[0014] Secondly, embodiments of this application provide a motor operation method, applied to the motor control system described in any of the first aspects. The method includes: collecting current data during motor operation via a power supply data sampling module and sending the current data to the frequency converter; obtaining power information of the motor during operation via the frequency converter based on the current data, and adjusting the output reactive current based on the power information to provide reactive power to the motor during power frequency operation, thereby setting the power factor of the motor to a predetermined power factor value.

[0015] In one possible implementation, the number of motors is at least N, where N is an integer greater than or equal to 2;

[0016] The step of collecting current data of the motor during operation through the power supply data sampling module and sending the current data to the frequency converter includes: collecting at least NM current data points of the motor during operation through the power supply data sampling module and sending the current data to the frequency converter; wherein, M is a non-negative integer less than or equal to N-1;

[0017] The step of obtaining power information of the motor during operation based on the current data through the frequency converter, and adjusting the output reactive current based on the power information to provide reactive power to the motor during the power frequency operation, so that the power factor of the motor is a predetermined power factor value, includes: obtaining power information of at least NM motors during operation based on the current data through the frequency converter, and adjusting the output reactive current based on the power information to provide reactive power to at least NM motors during the power frequency operation, so that the power factor of at least NM motors is a predetermined power factor value.

[0018] In one possible implementation, before collecting the current data of the motor during operation through the power supply data sampling module and sending the current data to the frequency converter, the method further includes: controlling the first isolating switch to close, causing the frequency converter to enter a standby preparation state; in the standby preparation state, controlling the second isolating switch to close through the frequency converter, causing the motor control system to operate in a soft start mode.

[0019] In one possible implementation, after the motor control system is put into soft-start mode, the method further includes: controlling the third disconnect switch to close according to the operating state of the motor, so that the motor control system enters grid drag mode and / or power factor enhancement mode.

[0020] In one possible implementation, after the motor control system enters the grid-driven mode, the method further includes: controlling the state of the first disconnect switch and the second disconnect switch according to the power factor improvement requirement.

[0021] In one possible implementation, after the motor control system enters the grid-driven mode, the method further includes: collecting real-time current data of the motor during operation through a power supply data sampling module and sending the real-time current data to the frequency converter; determining, through the frequency converter, whether the power factor of the motor corresponding to the real-time current data has reached the predetermined power factor value; if the power factor of the motor corresponding to the real-time current data has not reached the predetermined power factor value, obtaining real-time power information of the motor during operation based on the real-time current data, and adjusting the output real-time reactive current according to the real-time power information to provide real-time reactive power to the motor, so that the power factor of the motor reaches the predetermined power factor value; if the power factor of the motor corresponding to the real-time current data has reached the predetermined power factor value, then returning to the step of collecting real-time current data of the motor during operation through the power supply data sampling module and sending the real-time current data to the frequency converter.

[0022] In one possible implementation, after the motor control system enters the power factor improvement mode, the method further includes: controlling the first disconnect switch, the second disconnect switch, and the third disconnect switch to remain closed.

[0023] In one possible implementation, the power factor is predetermined to be 1.0.

[0024] The motor control system and motor operation method provided in this application, by deploying a power supply data sampling module, collects current data during motor operation and sends the current data to the frequency converter. The frequency converter obtains power information of the motor during operation based on the current data and adjusts the output reactive current according to the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is at a predetermined value. This solves the problem of low power factor of the motor during power frequency operation in the prior art. It achieves the effect of improving the power factor of the motor during power frequency operation. Since the frequency converter needs to compensate for the power factor of the motor, the frequency converter does not stop or power off, which also helps to maintain the life and health of the electronic components in the frequency converter and improves the utilization rate of the frequency converter. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] Figure 1 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 1 ;

[0027] Figure 2 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 2 ;

[0028] Figure 3 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 3 ;

[0029] Figure 4 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 4 ;

[0030] Figure 5 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 5 ;

[0031] Figure 6 A flowchart illustrating a motor operation method provided in one embodiment of this application;

[0032] Figure 7 This is a schematic diagram of a motor power transfer process provided in one embodiment of this application.

[0033] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0035] The technical solution of this application involves the collection, storage, use, processing, transmission, provision and disclosure of user personal information and data, which comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0036] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0037] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0038] Figure 1 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 1 ,like Figure 1 As shown, the motor control system provided in this embodiment includes a frequency converter, a power supply data sampling module, and a motor.

[0039] The inverter's input terminal is connected to the output terminal of the power grid; the motor's input terminal is connected to both the inverter's output terminal and the power grid's output terminal; the power supply data sampling module's input terminal is located at the motor's input terminal, and the power supply data sampling module is connected to the inverter.

[0040] The power supply data sampling module is used to collect current data during motor operation and send the current data to the frequency converter. The frequency converter is used to obtain power information of the motor during operation based on the current data and adjust the output reactive current according to the power information to provide reactive power to the motor when the motor is running at the power frequency, so that the power factor of the motor is at the predetermined power factor value.

[0041] In one possible implementation, the power information includes the power factor or reactive power during motor operation.

[0042] The motor control system provided in this embodiment is applicable to high-voltage power grids, with the high voltage range of the high-voltage power grid being, for example, 1kV to 220kV.

[0043] In summary, in this embodiment, by deploying a power supply data sampling module, the current data of the motor during operation is collected and sent to the frequency converter. The frequency converter obtains the power information of the motor during operation based on the current data and adjusts the output reactive current according to the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is at a predetermined value. This solves the problem of low power factor of the motor during power frequency operation in the prior art. It achieves the effect of improving the power factor of the motor during power frequency operation. Since the frequency converter needs to compensate for the power factor of the motor, the frequency converter does not stop or power off, which also helps to maintain the life and health of the electronic components in the frequency converter and improves the utilization rate of the frequency converter.

[0044] In existing technologies, motors are typically soft-started using frequency converters, which gradually increase the motor speed to the power frequency to achieve a smooth start. After the soft start is complete, the motor switches to power grid operation. However, motors operating at power frequency suffer from a low power factor. The motor control system provided in this application can solve this problem.

[0045] exist Figure 1 Based on the system diagram of the motor control system shown, Figure 2 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 2 ,like Figure 2 As shown, the motor control system provided in this embodiment also includes a first disconnect switch, a second disconnect switch, and a third disconnect switch.

[0046] The inverter's input terminal is connected to the power grid via a first isolating switch, and the inverter's output terminal is connected to the motor's input terminal via a second isolating switch; the motor's input terminal is connected to the power grid via a third isolating switch.

[0047] The input terminal of the power supply data sampling module is located between the third disconnecting switch and the output terminal of the power frequency grid, and / or between the third disconnecting switch and the input terminal of the motor, and / or between the second disconnecting switch and the input terminal of the motor.

[0048] In this embodiment, multi-point distributed sampling eliminates the local error of a single current sampling point, improves the comprehensiveness and accuracy of current monitoring, solves the compensation lag problem caused by local sampling errors, and ensures that the frequency converter can quickly respond to the load fluctuation of the motor, thereby further optimizing the power factor compensation effect of the motor.

[0049] exist Figure 2 Based on the system diagram of the motor control system shown, Figure 3 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 3 ,like Figure 3 As shown, the number of motors is at least N, where N is an integer greater than or equal to 2; the input terminals of at least NM motors are connected to the output terminals of the frequency converter through corresponding second disconnect switches, and connected to the power grid through corresponding third disconnect switches; where M is a non-negative integer less than or equal to N-1.

[0050] Furthermore, the output terminal of the power frequency grid is connected to at least two motors through the power supply trunk line and the power supply branch line; the input terminal of the power supply data sampling module is set on the power supply branch line where the third isolating switch corresponding to each motor is located, and / or, is set on the power supply trunk line.

[0051] Each power supply branch is connected to the main power supply line through a branch junction point; when the input terminal of the power supply data sampling module is set on the power supply branch where the third disconnecting switch corresponding to each motor is located, the input terminal of the power supply data sampling module is set between each third disconnecting switch and the branch junction point, and / or between each third disconnecting switch and the input terminal of the motor, and / or between each second disconnecting switch and the input terminal of the motor.

[0052] For example, such as Figure 3 As shown, N is 3, and the input terminals of the three motors are connected to the output terminal of the frequency converter through corresponding second disconnect switches, and connected to the power grid through corresponding third disconnect switches. Figure 3 As shown, the output of the power frequency grid is connected to three motors through the main power supply circuit and the power supply branch circuit. The input of the power supply data sampling module can be set on the main power supply circuit or on the power supply branch circuit where the third disconnecting switch for each motor is located (e.g., Figure 3 As shown, it is installed between each third disconnect switch and the branch junction point.

[0053] exist Figure 2 Based on the system diagram of the motor control system shown, Figure 4 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 4 ,like Figure 4As shown, the motor control system provided in this embodiment also includes a filter; the output terminal of the frequency converter is electrically connected to the second isolation switch through the filter.

[0054] The filter is used to filter the voltage waveform and current waveform of the inverter output voltage to obtain the filtered voltage and current, which are then input to the motor.

[0055] In one possible implementation, the filter is a combination of digitally controlled adjustable inductors (L) and capacitors (C), or a dynamically tuned filter based on a switched capacitor array.

[0056] In this embodiment, the filter analyzes the harmonic frequency distribution of the power grid in real time through a harmonic detection module and dynamically adjusts the parameters of the adjustable inductor and capacitor to match the resonant frequency of the filter with the harmonic frequency of the power grid. The voltage and current output by the frequency converter are filtered after passing through the filter, and high-order harmonics are effectively suppressed. The voltage waveform and current waveform input to the motor are closer to sine waves, reducing the additional losses (such as iron loss and copper loss) caused by harmonics in the motor and extending the service life of the motor.

[0057] exist Figure 2 Based on the system diagram of the motor control system shown, Figure 5 A schematic diagram of a motor control system provided in one embodiment of this application. Figure 5 ,like Figure 5 As shown, the power grid connected to the motor control system provided in this embodiment includes a first power grid and a second power grid, and the motor control system also includes a voltage sampling module.

[0058] The inverter's input terminal is connected to the output terminal of the first power frequency grid; the motor's input terminal is connected to the output terminal of the inverter and the output terminal of the second power frequency grid; the voltage sampling module's input terminal is located at the output terminal of the second power frequency grid, and the voltage sampling module is connected to the inverter.

[0059] The power supply data sampling module is used to collect current data during motor operation and send the current data to the frequency converter. The frequency converter is used to obtain power information of the motor during operation based on the current data and adjust the output reactive current according to the power information to provide reactive power to the motor when the motor is running at the power frequency, so that the power factor of the motor is at the predetermined power factor value. The voltage sampling module is used to collect voltage information of the second power frequency grid so that after the motor is soft-started based on the first power frequency grid, the third disconnecting switch is closed after the voltage at the input end of the motor and the output end of the second power frequency grid are equal, so as to achieve synchronous grid connection.

[0060] In some embodiments, the control of closing the third isolating switch is achieved by a frequency converter.

[0061] In one possible implementation, the operating modes of the motor control system include at least soft-start mode, power factor improvement mode, and grid-driven mode;

[0062] Specifically, when the motor control system is operating in soft-start mode, the first and second disconnect switches are closed; when the motor control system is operating in power factor improvement mode, the first, second, and third disconnect switches are closed; and when the motor control system is operating in grid-driven mode, the third disconnect switch is closed.

[0063] In the case where the motor control system is operating in grid-driven mode, if it is necessary to use the frequency converter to improve the power factor of the motor, the first disconnect switch and the second disconnect switch are in the closed state; if it is not necessary to use the frequency converter to improve the power factor of the motor, the first disconnect switch and the second disconnect switch are in the open state.

[0064] Furthermore, in one possible implementation, the power factor is predetermined to be 1.0 in the motor control system provided in this application.

[0065] In the motor control system provided in this application embodiment, the method of improving the power factor of the motor by using a frequency converter to keep the frequency converter running also solves the problem of accelerated aging of the frequency converter caused by the frequency converter driving the motor in the prior art after a soft start and being in a standby or power-off state for a long time. It also avoids the risk of failure when the frequency converter is restarted after being in a standby or power-off state for a long time.

[0066] Figure 6 A flowchart of a motor operation method provided in one embodiment of this application is shown below. Figure 6 As shown, the motor operation method provided in this embodiment is applied to... Figures 1 to 5 The motor control system shown in any embodiment, and the motor operation method provided in this embodiment, include the following steps:

[0067] Step S601: Collect the current data of the motor during operation through the power supply data sampling module, and send the current data to the frequency converter.

[0068] In step S602, the inverter obtains the power information of the motor during operation based on the current data, and adjusts the output reactive current according to the power information to provide reactive power to the motor when it is running at the power frequency, so that the power factor of the motor is at the predetermined power factor value.

[0069] The inverter includes a phase-locked loop (PLL) module. The PLL module is used to synchronize the frequency and phase of the power grid voltage when the motor is running at the power frequency to generate a reference signal that is synchronized with the power grid. Then, the inverter adjusts its own output frequency and phase according to the reference signal to ensure that it is in phase with the voltage signal of the grid. Then, the inverter inputs voltage and current to the motor according to the power supply data to provide reactive power to the motor so that the motor can run.

[0070] In this embodiment, by deploying a power supply data sampling module, the current data of the motor during operation is collected and sent to the frequency converter. The frequency converter obtains the power information of the motor during operation based on the current data and adjusts the output reactive current according to the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is at a predetermined value, thus solving the problem of low power factor of the motor during power frequency operation in the prior art.

[0071] In another possible implementation, the number of motors is at least N, where N is an integer greater than or equal to 2; then the implementation steps of step S601 include:

[0072] The power supply data sampling module collects current data from at least NM motors during operation and sends the current data to the frequency converter; where M is a non-negative integer less than or equal to N-1.

[0073] The implementation steps of step S602 include:

[0074] The inverter obtains power information of at least NM motors during operation based on current data, and adjusts the output reactive current based on the power information to provide reactive power to at least NM motors during power frequency operation, so that the power factor of at least NM motors is at a predetermined value.

[0075] For example, refer to Figure 3 The motor control system shown has three motors. The frequency converter generates reactive power compensation allocation information based on the current data of the three motors. This information indicates how to provide corresponding reactive power compensation to each motor according to its load state. Furthermore, the frequency converter provides the corresponding reactive power to each motor based on the reactive power compensation allocation information, ensuring that the power factor of the corresponding motor is at a predetermined value.

[0076] In the embodiments of this application, the problem of uneven reactive power compensation caused by the load differences of multiple motors is solved, the overall energy efficiency of the motor control system is improved, and the adaptability to complex load fluctuations is enhanced.

[0077] Furthermore, in one possible implementation, prior to step S601, the method provided in this application embodiment further includes:

[0078] Step S6001: By controlling the first isolation switch to close, the frequency converter is put into standby preparation state;

[0079] In step S6002, during standby preparation, the second isolating switch is closed by controlling the frequency converter, so that the motor control system operates in soft start mode.

[0080] The operation of controlling the closing of the first isolating switch includes manual control of closing and closing in response to a system start command.

[0081] Furthermore, in one possible implementation, before step S601 and after step S6002, the method provided in this application embodiment further includes:

[0082] The third isolating switch is closed according to the motor's operating status, causing the motor control system to enter the grid-driven mode and / or power factor enhancement mode.

[0083] The control of closing the third disconnect switch based on the motor's operating state includes: closing the third disconnect switch after the voltage at the motor's input terminal is equal to the voltage at the output terminal of the power grid; that is, closing the third disconnect switch when the motor's operating state is such that the voltage at the motor's input terminal is equal to the voltage at the output terminal of the power grid. In some embodiments, the control of closing the third disconnect switch is implemented by a frequency converter.

[0084] When the motor control system is operating in power factor improvement mode, the motor is driven by the power frequency grid. That is, when the motor control system enters power factor improvement mode, it is also necessary to control the closing of the third disconnect switch.

[0085] For example, Figure 7 This is a schematic diagram of a motor power transfer process provided in one embodiment of this application, as shown below. Figure 7As shown, the dashed line represents the active power provided by the frequency converter, the long dashed line represents the reactive power provided by the frequency converter, the solid line represents the active power provided by the power grid, and the double dashed line represents the reactive power provided by the power grid. The horizontal axis represents time, and the vertical axis represents the power value. Time point T1 represents the time when the third disconnecting switch is closed and the time when the motor power transfer begins. Time point T2 represents the time when the motor power transfer is completed. That is, the time period from time point T1 to time point T2 is the mode switching process. Time point T1 is the start time of the mode switching process, and time point T2 is the end time of the mode switching process. The power values ​​P1 and P2 are greater than 0, and P0 is equal to 0. Before time point T1, when the motor control system is not operating in power factor improvement mode, the active power provided by the frequency converter is P2, the reactive power provided by the frequency converter is P1, and the active and reactive power provided by the power grid are both P0. At time point T1 (the start of the mode switching process), the motor control system starts operating in power factor improvement mode and begins motor power transfer. The active power provided by the frequency converter decreases from P2 to P0 at time point T2, meaning that after time point T2, the active power provided by the frequency converter is 0. At the same time, the active power provided by the power grid increases from P0 to P2 at time point T2, meaning that after time point T2, all the active power required for motor operation is provided by the power grid. Meanwhile, before, during, and after the motor power transfer, the reactive power provided by the frequency converter to the motor remains unchanged at P1, and the reactive power provided by the power grid remains unchanged at P0, meaning that no reactive power is required from the power grid to the motor.

[0086] In one possible implementation, after the motor control system enters the grid-driven mode, the method provided in this application embodiment further includes:

[0087] The states of the first and second disconnect switches are controlled according to the power factor improvement requirements.

[0088] For example, if it is determined that a power factor improvement is needed based on the power factor improvement requirement, then the first disconnect switch and the second disconnect switch are controlled to be in the closed state; if it is determined that a power factor improvement is not needed based on the power factor improvement requirement, then the first disconnect switch and the second disconnect switch are controlled to be in the open state.

[0089] In another possible implementation, after the motor control system enters the grid-driven mode, the method provided in this application embodiment further includes:

[0090] The power supply data sampling module collects real-time current data during motor operation and sends the real-time current data to the frequency converter.

[0091] The inverter is used to determine whether the power factor of the motor corresponding to the real-time current data has reached the predetermined power factor value.

[0092] If the power factor of the motor corresponding to the real-time current data does not reach the predetermined power factor value, then the real-time power information of the motor during operation is obtained based on the real-time current data, and the real-time reactive current output is adjusted according to the real-time power information to provide real-time reactive power to the motor so that the power factor of the motor reaches the predetermined power factor value.

[0093] If the power factor of the motor corresponding to the real-time current data reaches the predetermined power factor value, the real-time current data of the motor during operation will be collected through the power supply data sampling module and sent to the frequency converter.

[0094] After the motor control system enters the grid-driven mode, it can monitor the real-time current data of the motor operation in real time. Then, based on the power factor of the motor corresponding to the real-time current data, it can determine whether power factor improvement is needed. This achieves the effect of dynamically adjusting the motor power factor according to the actual operating conditions of the motor, reducing the idle rate of the frequency converter, and improving the reliability of the frequency converter.

[0095] After the motor control system enters the power factor improvement mode, the method provided in this application embodiment further includes: controlling the first disconnect switch, the second disconnect switch, and the third disconnect switch to remain closed.

[0096] In the method provided in this application embodiment, the power factor is predetermined to be 1.0.

[0097] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0098] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0099] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0100] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0101] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0102] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0103] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0104] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0105] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0106] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A motor control system, characterized in that, Includes frequency converter, power supply data sampling module, and motor; The input terminal of the frequency converter is connected to the output terminal of the power frequency grid. The input terminal of the motor is connected to the output terminal of the frequency converter and the output terminal of the power grid. The input terminal of the power supply data sampling module is located at the input terminal of the motor, and the power supply data sampling module is connected to the frequency converter; The power supply data sampling module is used to collect the current data of the motor during operation and send the current data to the frequency converter; The frequency converter is used to obtain the power information of the motor during operation based on the current data, and adjust the output reactive current according to the power information to provide reactive power to the motor when the motor is running at the power frequency, so that the power factor of the motor is a predetermined value.

2. The motor control system according to claim 1, characterized in that, It also includes a first disconnecting switch, a second disconnecting switch, and a third disconnecting switch; The input terminal of the frequency converter is connected to the power grid through the first isolating switch, and the output terminal of the frequency converter is connected to the input terminal of the motor through the second isolating switch. The input terminal of the motor is connected to the power grid via the third disconnect switch; The input terminal of the power supply data sampling module is located between the third disconnecting switch and the output terminal of the power frequency grid, and / or between the third disconnecting switch and the input terminal of the motor, and / or between the second disconnecting switch and the input terminal of the motor.

3. The motor control system according to claim 2, characterized in that, The number of motors is at least N, where N is an integer greater than or equal to 2; At least NM of the motors have their input terminals connected to the output terminals of the frequency converter via corresponding second disconnect switches, and connected to the power grid via corresponding third disconnect switches; wherein M is a non-negative integer less than or equal to N-1.

4. The motor control system according to claim 3, characterized in that, The output terminal of the power frequency grid is connected to at least two of the motors through a power supply trunk line and a power supply branch line; The input terminal of the power supply data sampling module is located on the power supply branch where the third isolating switch corresponding to each motor is located, and / or on the main power supply circuit.

5. The motor control system according to claim 4, characterized in that, Each of the aforementioned power supply branches is connected to the power supply trunk line through a branch junction point; When the input terminal of the power supply data sampling module is set on the power supply branch where the third disconnecting switch corresponding to each motor is located, the input terminal of the power supply data sampling module is set between each third disconnecting switch and the branch junction point, and / or between each third disconnecting switch and the input terminal of the motor, and / or between each second disconnecting switch and the input terminal of the motor.

6. The motor control system according to claim 2, characterized in that, The operating modes of the motor control system include at least soft start mode, power factor improvement mode, and grid drag mode; When the motor control system is operating in the soft-start mode, the first disconnect switch and the second disconnect switch are closed. When the motor control system is operating in the power factor improvement mode, the first disconnect switch, the second disconnect switch, and the third disconnect switch are closed; When the motor control system is operating in the grid drag mode, the third disconnect switch is closed.

7. The motor control system according to claim 2, characterized in that, The power frequency grid includes a first power frequency grid and a second power frequency grid, and the motor control system further includes a voltage sampling module; The input terminal of the frequency converter is connected to the output terminal of the first power frequency grid; the input terminal of the motor is connected to the output terminal of the frequency converter and the output terminal of the second power frequency grid; the input terminal of the voltage sampling module is located at the output terminal of the second power frequency grid, and the voltage sampling module is connected to the frequency converter.

8. The motor control system according to any one of claims 1 to 7, characterized in that, The power factor is predefined as 1.

0.

9. A method for operating a motor, characterized in that, Applied to the motor control system as described in any one of claims 1 to 8, the method comprises: The power supply data sampling module collects the current data of the motor during operation and sends the current data to the frequency converter. The inverter obtains the power information of the motor during operation based on the current data, and adjusts the output reactive current according to the power information to provide reactive power to the motor when it is running at the power frequency, so that the power factor of the motor is at a predetermined value.

10. The method according to claim 9, characterized in that, The number of motors is at least N, where N is an integer greater than or equal to 2; The step of collecting current data of the motor during operation through the power supply data sampling module and sending the current data to the frequency converter includes: The power supply data sampling module collects at least NM current data points during motor operation and sends these current data points to the frequency converter; wherein M is a non-negative integer less than or equal to N-1. The step of obtaining power information of the motor during operation based on the current data through the frequency converter, and adjusting the output reactive current based on the power information to provide reactive power to the motor during power frequency operation, so that the power factor of the motor is at a predetermined value, includes: The inverter obtains the power information of the at least NM motors during operation based on the current data, and adjusts the output reactive current based on the power information to provide reactive power to the at least NM motors during power frequency operation, so that the power factor of the at least NM motors is a predetermined value.

11. The method according to any one of claims 9 to 10, characterized in that, Before acquiring the motor's current data during operation via the power supply data sampling module and sending the current data to the frequency converter, the method further includes: By controlling the first isolating switch to close, the frequency converter is put into standby preparation state; In the standby preparation state, the second isolating switch is closed by controlling the frequency converter, so that the motor control system operates in soft start mode.

12. The method according to claim 11, characterized in that, After the motor control system is put into soft-start mode, the method further includes: The third isolating switch is closed according to the operating status of the motor, causing the motor control system to enter the grid drag mode and / or power factor improvement mode.

13. The method according to claim 12, characterized in that, After the motor control system enters the grid-driven mode, the method further includes: The states of the first disconnect switch and the second disconnect switch are controlled according to the power factor improvement requirements.

14. The method according to claim 12, characterized in that, After the motor control system enters the grid-driven mode, the method further includes: The power supply data sampling module collects real-time current data of the motor during operation and sends the real-time current data to the frequency converter. The inverter is used to determine whether the power factor of the motor corresponding to the real-time current data has reached the predetermined power factor value. If the power factor of the motor corresponding to the real-time current data does not reach the predetermined power factor value, then the real-time power information of the motor during operation is obtained according to the real-time current data, and the real-time reactive current output is adjusted according to the real-time power information to provide real-time reactive power to the motor so that the power factor of the motor reaches the predetermined power factor value. If the power factor of the motor corresponding to the real-time current data reaches the predetermined power factor value, then the process returns to the step of collecting the real-time current data of the motor during operation through the power supply data sampling module and sending the real-time current data to the frequency converter.

15. The method according to claim 11, characterized in that, After the motor control system enters the power factor improvement mode, the method further includes: Control the first disconnect switch, the second disconnect switch, and the third disconnect switch to remain closed.

16. The method according to any one of claims 9 to 10, characterized in that, The power factor is predefined as 1.0.

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