Crane frequency conversion control energy-saving method and system

Abstract

The invention relates to the technical field of automation control, in particular to a crane frequency conversion control energy-saving method and system, and the method comprises the following steps: determining the rated load weight of a crane according to the real-time motor rotating speed; calculating a load error according to the actual load weight and the rated load weight, and correcting the real-time motor rotating speed according to the load error to obtain a motor corrected rotating speed; adjusting the correction rotating speed of the motor for the first time according to the lifting height; and according to the external environment data, carrying out secondary adjustment on the motor correction rotation speed, and taking the motor correction rotation speed after secondary adjustment as the motor operation rotation speed. Through real-time monitoring, accurate calculation and dynamic adjustment of the rotating speed of the motor, efficient, stable and safe control over the crane motor is achieved, the operation efficiency and the energy utilization rate of the crane are improved, the service life of equipment is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of automation control technology, and in particular to a crane variable frequency control energy-saving method and system. Background Art

[0002] Traditional cranes are mostly driven by wound-rotor asynchronous motors in their electric traction systems, and use relay-contactor control to change the multi-segment resistors in series in the rotor circuit for step-by-step speed regulation. This control method has many drawbacks, such as high energy consumption, low efficiency, low low-speed starting torque, soft mechanical characteristics, poor speed regulation stability, high line failure rate, and high maintenance requirements. These problems not only increase the operating costs of enterprises, but also affect the operating efficiency and safety of cranes.

[0003] As the global energy crisis and environmental problems become increasingly serious, governments around the world have introduced energy-saving and environmental protection policies to encourage and support the research, development, demonstration and promotion of energy-saving technologies. As one of the widely used equipment in the industrial field, the energy-saving transformation of cranes has become an important way to achieve industrial energy conservation. Therefore, the research and development of crane variable frequency control energy-saving methods and systems has important practical significance and broad market prospects.

[0004] Therefore, how to solve the problems of high energy consumption and low efficiency of traditional cranes has become a new trend in technological development. Summary of the invention

[0005] In view of this, the present invention proposes a crane variable frequency control energy-saving method and system, mainly to solve the problems of high energy consumption and low efficiency of traditional cranes.

[0006] In one aspect, the present invention provides a crane variable frequency control energy saving method, the method comprising:

[0007] Acquire the real-time motor speed of the crane, and determine the rated load weight of the crane according to the real-time motor speed;

[0008] Acquire the actual load weight of the crane, calculate the load error according to the actual load weight and the rated load weight, and correct the real-time motor speed according to the load error to obtain the motor correction speed;

[0009] After the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is acquired, and the motor correction speed is adjusted once according to the lifting height;

[0010] After the motor speed is adjusted once according to the lifting height, external environment data is acquired, and the motor correction speed is adjusted twice according to the external environment data, and the motor correction speed after the second adjustment is used as the motor operating speed.

[0011] In some embodiments of the present application, obtaining the actual load weight of the crane, calculating the load error according to the actual load weight and the rated load weight, correcting the real-time motor speed according to the load error, and obtaining the corrected motor speed includes:

[0012] The rated load weight is recorded as Wt, and the actual load weight is recorded as Wr;

[0013] The load error is recorded as W, W = Wt-Wr;

[0014] A load difference correction threshold Wa is preset, and Wa>0;

[0015] When -Wa<W<Wa, it is determined that the real-time motor speed is not corrected according to the load error, and the real-time motor speed is used as the motor correction speed;

[0016] When W≤-Wa or W≥Wa, it is determined to correct the real-time motor speed according to the load error.

[0017] In some embodiments of the present application, when W≤-Wa or W≥Wa, determining to correct the real-time motor speed according to the load error includes:

[0018] Preset the speed control gain Kp;

[0019] Calculate the speed correction amount ΔW according to the speed control gain Kp and the load error W, ΔW=Kp×W;

[0020] The real-time motor speed is recorded as V;

[0021] The real-time motor speed V is adjusted according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, where Va=V+ΔW.

[0022] In some embodiments of the present application, after adjusting the real-time motor speed V according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, the method further includes:

[0023] Preset the maximum motor speed threshold Vmax and the minimum motor speed threshold Vmin;

[0024] When Vmin<Va<Vmax, the adjusted real-time motor speed Va is used as the motor correction speed;

[0025] When Va≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed;

[0026] When Va≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

[0027] In some embodiments of the present application, after the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is obtained, and the motor correction speed is adjusted once according to the lifting height, including:

[0028] The motor correction speed is recorded as Vx;

[0029] The lifting height is recorded as H;

[0030] A first preset lifting height threshold H1 and a second preset lifting height threshold H2 are preset, and H1>H2; a first preset height adjustment coefficient h1, a second preset height adjustment coefficient h2, and a third preset height adjustment coefficient h3 are preset, and 0.9

[0031] When H>H1, the first preset height adjustment coefficient h1 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h1;

[0032] When H1≥H>H2, the second preset height adjustment coefficient h2 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h2;

[0033] When H3≥H, the third preset height adjustment coefficient h3 is selected to perform a one-time adjustment on the motor correction speed Vx, and the motor correction speed after the one-time adjustment is Vx*h3.

[0034] In some embodiments of the present application, the external environment data includes real-time ambient temperature and real-time ambient wind speed.

[0035] In some embodiments of the present application, after selecting the i-th preset height adjustment coefficient hi to adjust the motor correction speed Vx once, i=1, 2, 3, and obtaining the motor correction speed after the adjustment as Vx*hi, the method further includes:

[0036] Obtaining the real-time temperature of the environment, and recording the real-time temperature of the environment as T;

[0037] Obtain the real-time wind speed of the environment, and record the real-time wind speed of the environment as F;

[0038] Preset the maximum temperature threshold Tmax and the maximum wind speed threshold Fmax;

[0039] ​A first preset environment adjustment coefficient n1, a second preset environment adjustment coefficient n2 and a third preset environment adjustment coefficient n3 are preset, and 0.8<n1<n2<n3, n3=1;

[0040] When T≤Tmax and F≤Fmax, the third preset environment adjustment coefficient n3 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n3;

[0041] When T>Tmax or F>Fmax, the second preset environment adjustment coefficient n2 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n2;

[0042] When T>Tmax and F>Fmax, the first preset environment adjustment coefficient n1 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after the secondary adjustment is Vx*hi*n1.

[0043] In some embodiments of the present application, after selecting the i-th preset environment adjustment coefficient ni to perform secondary adjustment on the motor correction speed Vx, i=1, 2, 3, and obtaining the motor correction speed after secondary adjustment as Vx*hi*ni, the following is further included:

[0044] When Vmin<Vx*hi*ni<Vmax, the motor correction speed Vx*hi*ni after secondary adjustment is used as the motor running speed;

[0045] When Vx*hi*ni≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed;

[0046] When Vx*hi*ni≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

[0047] In another aspect, the present invention provides a crane variable frequency control energy-saving system, the system comprising:

[0048] A data acquisition unit, used for acquiring a real-time motor speed of the crane, and determining a rated load weight of the crane according to the real-time motor speed;

[0049] A load correction unit, used for obtaining the actual load weight of the crane, calculating a load error according to the actual load weight and the rated load weight, and correcting the real-time motor speed according to the load error to obtain a motor correction speed;

[0050] The environment adjustment unit is used to obtain the lifting height of the crane after the load correction unit corrects the real-time motor speed according to the load error to obtain the motor correction speed, and adjust the motor correction speed once according to the lifting height; after the motor speed is adjusted once according to the lifting height, obtain external environment data, make a second adjustment to the motor correction speed according to the external environment data, and use the motor correction speed after the second adjustment as the motor operating speed.

[0051] Compared with the prior art, the present invention has the following beneficial effects: the present invention obtains the motor speed of the crane in real time, determines the rated load weight of the crane according to the motor speed, and then calculates the load error in combination with the actual load weight of the crane. According to the load error, the real-time speed of the motor is dynamically adjusted to ensure that the motor can accurately match the actual load during operation, thereby avoiding energy waste and mechanical loss caused by excessively high or low motor speed. The lifting height of the crane and the influence of external environmental factors on the motor speed can be obtained by obtaining the lifting height of the crane and adjusting the motor speed once according to the lifting height, thereby ensuring that the motor can maintain stable performance at different heights. At the same time, by obtaining external environmental data (such as real-time ambient temperature and wind speed) and adjusting the motor speed twice according to these data, the stability and safety of the motor operation can be further improved, thereby avoiding the adverse effects of harsh environments on the motor. The present invention realizes efficient, stable and safe control of the crane motor by real-time monitoring, accurate calculation and dynamic adjustment of the motor speed. This not only improves the operating efficiency and energy utilization of the crane, but also extends the service life of the equipment and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

[0053] Figure 1 A flow chart of a crane variable frequency control energy saving method provided by an embodiment of the present invention;

[0054] Figure 2 This is a result block diagram of the crane variable frequency control energy-saving system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the implementation regulations.

[0056] See also Figure 1 As shown, this embodiment provides a crane variable frequency control energy saving method, the method comprising:

[0057] S101: Acquire a real-time motor speed of a crane, and determine a rated load weight of the crane according to the real-time motor speed;

[0058] S102: Acquire the actual load weight of the crane, calculate a load error according to the actual load weight and the rated load weight, and correct the real-time motor speed according to the load error to obtain a corrected motor speed;

[0059] S103: After the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is acquired, and the motor correction speed is adjusted once according to the lifting height;

[0060] S104: After the motor speed is adjusted once according to the lifting height, external environment data is acquired, and the motor correction speed is adjusted twice according to the external environment data, and the motor correction speed after the second adjustment is used as the motor operating speed.

[0061] It can be understood that in this embodiment, the rated load weight is determined by obtaining the motor speed of the crane in real time. This step can ensure that the crane has an accurate load judgment benchmark under different working conditions. Then, by comparing the actual load weight with the rated load weight, the load error is calculated, and the real-time motor speed is corrected according to this error, so as to obtain a more accurate motor correction speed. This step effectively improves the operation efficiency of the crane and reduces unnecessary energy consumption. After obtaining the motor correction speed, the motor correction speed is adjusted once according to the lifting height, ensuring that the crane can maintain a stable operating state during the lifting process, further improving the work efficiency and safety. By obtaining external environmental data (such as wind speed, temperature, etc.), the motor correction speed is adjusted twice, so that the crane can adapt to different working environments and ensure that it can operate efficiently and safely under various conditions. The crane variable frequency control energy-saving method provided in this embodiment realizes the energy-saving operation of the crane by correcting the motor speed in real time, considering multiple factors such as lifting height and external environmental data, which can not only improve the operation efficiency of the crane, reduce energy consumption, but also ensure the operation safety of the crane.

[0062] In some embodiments of the present application, obtaining the actual load weight of the crane, calculating the load error according to the actual load weight and the rated load weight, correcting the real-time motor speed according to the load error, and obtaining the corrected motor speed includes:

[0063] The rated load weight is recorded as Wt, and the actual load weight is recorded as Wr;

[0064] The load error is recorded as W, W = Wt-Wr;

[0065] A load difference correction threshold Wa is preset, and Wa>0;

[0066] When -Wa<W<Wa, it is determined that the real-time motor speed is not corrected according to the load error, and the real-time motor speed is used as the motor correction speed;

[0067] When W≤-Wa or W≥Wa, it is determined to correct the real-time motor speed according to the load error.

[0068] In some embodiments of the present application, when W≤-Wa or W≥Wa, determining to correct the real-time motor speed according to the load error includes:

[0069] Preset the speed control gain Kp;

[0070] Calculate the speed correction amount ΔW according to the speed control gain Kp and the load error W, ΔW=Kp×W;

[0071] The real-time motor speed is recorded as V;

[0072] The real-time motor speed V is adjusted according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, where Va=V+ΔW.

[0073] In some embodiments of the present application, after adjusting the real-time motor speed V according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, the method further includes:

[0074] Preset the maximum motor speed threshold Vmax and the minimum motor speed threshold Vmin;

[0075] When Vmin<Va<Vmax, the adjusted real-time motor speed Va is used as the motor correction speed;

[0076] When Va≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed;

[0077] When Va≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

[0078] Specifically, the speed control gain Kp in this embodiment can be determined by debugging method, system modeling and simulation or critical proportion method, and this embodiment does not make any specific limitation.

[0079] It can be understood that in this embodiment, the load error is calculated by obtaining the actual load weight of the crane in real time and comparing it with the rated load weight. When the load error exceeds the preset load difference correction threshold, the system will correct the real-time speed of the motor according to the load error to ensure that the motor runs at a more appropriate speed, thereby improving the operation efficiency of the crane. At the same time, this speed correction based on the load error can avoid the unstable operation state of the crane under overload or underload conditions, thereby improving the safety of the crane. By adjusting the real-time speed of the motor according to the load error, the motor can be prevented from running at unnecessary high or low speeds, thereby reducing the energy consumption and wear of the motor and extending the service life of the motor. In this embodiment, by setting the maximum and minimum thresholds of the motor speed, it is ensured that the motor speed is always within a reasonable range, avoiding system instability or damage caused by excessively high or low speeds. The setting of the speed control gain Kp can be adjusted according to actual conditions to meet the needs of different loads and working environments, thereby enhancing the robustness and adaptability of the system. In this embodiment, by obtaining the actual load weight of the crane in real time and correcting the real-time speed of the motor accordingly, the operation efficiency and safety of the crane are improved, the energy consumption and life of the motor are optimized, and the robustness and adaptability of the system are enhanced. At the same time, simplified operating procedures and reduced maintenance costs have further enhanced the crane's use value and economic benefits.

[0080] In some embodiments of the present application, after the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is obtained, and the motor correction speed is adjusted once according to the lifting height, including:

[0081] The motor correction speed is recorded as Vx;

[0082] The lifting height is recorded as H;

[0083] A first preset lifting height threshold H1 and a second preset lifting height threshold H2 are preset, and H1>H2; a first preset height adjustment coefficient h1, a second preset height adjustment coefficient h2, and a third preset height adjustment coefficient h3 are preset, and 0.9

[0084] When H>H1, the first preset height adjustment coefficient h1 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h1;

[0085] When H1≥H>H2, the second preset height adjustment coefficient h2 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h2;

[0086] When H3≥H, the third preset height adjustment coefficient h3 is selected to perform a one-time adjustment on the motor correction speed Vx, and the motor correction speed after the one-time adjustment is Vx*h3.

[0087] It can be understood that in this embodiment, by selecting different preset height adjustment coefficients according to the lifting height to adjust the motor correction speed, it can be ensured that the crane can run at a more appropriate speed at different heights. For example, when the lifting height is high, a smaller adjustment coefficient (such as h1) is selected to appropriately reduce the motor speed, thereby reducing the risk caused by too fast operation and saving energy; and when the lifting height is low, a larger adjustment coefficient (such as h3) is selected, then the motor speed can be appropriately increased to improve work efficiency. During the operation of the crane, especially when the lifting height is high, if the motor speed is too fast, it may cause the crane to run unstably or even cause a safety accident. By adjusting the motor speed according to the lifting height, it can be ensured that the crane can run at a stable and safe speed at different heights, thereby greatly reducing the risk of safety accidents.

[0088] In some embodiments of the present application, the external environment data includes real-time ambient temperature and real-time ambient wind speed.

[0089] ​In some embodiments of the present application, after selecting the i-th preset height adjustment coefficient hi to adjust the motor correction speed Vx once, i=1, 2, 3, and obtaining the motor correction speed after the adjustment as Vx*hi, the method further includes:

[0090] Obtaining the real-time temperature of the environment, and recording the real-time temperature of the environment as T;

[0091] Obtain the real-time wind speed of the environment, and record the real-time wind speed of the environment as F;

[0092] Preset the maximum temperature threshold Tmax and the maximum wind speed threshold Fmax;

[0093] A first preset environment adjustment coefficient n1, a second preset environment adjustment coefficient n2 and a third preset environment adjustment coefficient n3 are preset, and 0.8<n1<n2<n3, n3=1;

[0094] When T≤Tmax and F≤Fmax, the third preset environment adjustment coefficient n3 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n3;

[0095] When T>Tmax or F>Fmax, the second preset environment adjustment coefficient n2 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n2;

[0096] When T>Tmax and F>Fmax, the first preset environment adjustment coefficient n1 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after the secondary adjustment is Vx*hi*n1.

[0097] In some embodiments of the present application, after selecting the i-th preset environment adjustment coefficient ni to perform secondary adjustment on the motor correction speed Vx, i=1, 2, 3, and obtaining the motor correction speed after secondary adjustment as Vx*hi*ni, the following is further included:

[0098] When Vmin<Vx*hi*ni<Vmax, the motor correction speed Vx*hi*ni after secondary adjustment is used as the motor running speed;

[0099] When Vx*hi*ni≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed;

[0100] When Vx*hi*ni≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

[0101] It can be understood that, in this embodiment, by introducing the real-time ambient temperature and the real-time ambient wind speed as adjustment factors, the operating speed of the motor can be adaptively adjusted according to different environmental conditions. The secondary adjustment of the motor speed according to the ambient temperature and wind speed can ensure that the motor operates within the high-efficiency range. When the ambient temperature and wind speed are low, the motor can run at a higher speed to improve work efficiency; when the environmental conditions are harsh, the motor speed is reduced to reduce energy consumption and wear. By setting the minimum and maximum thresholds of the motor speed, it is ensured that the motor speed is always within a safe range. Even under the worst environmental conditions, it can effectively avoid safety problems that may be caused by overspeeding or too slow of the motor. In summary, the method provided in this embodiment not only improves the environmental adaptability and energy efficiency of the equipment, but also enhances the safety and ease of operation of the equipment by combining real-time external environmental data to make secondary adjustments to the motor correction speed.

[0102] See also Figure 2 As shown, in another aspect, the present invention proposes a crane variable frequency control energy-saving system, the system comprising:

[0103] A data acquisition unit, used for acquiring a real-time motor speed of the crane, and determining a rated load weight of the crane according to the real-time motor speed;

[0104] A load correction unit, used for obtaining the actual load weight of the crane, calculating a load error according to the actual load weight and the rated load weight, and correcting the real-time motor speed according to the load error to obtain a motor correction speed;

[0105] The environment adjustment unit is used to obtain the lifting height of the crane after the load correction unit corrects the real-time motor speed according to the load error to obtain the motor correction speed, and adjust the motor correction speed once according to the lifting height; after the motor speed is adjusted once according to the lifting height, obtain external environment data, make a second adjustment to the motor correction speed according to the external environment data, and use the motor correction speed after the second adjustment as the motor operating speed.

[0106] It can be understood that the data acquisition unit in this embodiment obtains the motor speed of the crane in real time, and determines the rated load weight accordingly, providing an accurate reference for the entire system. The load correction unit obtains the actual load weight and compares it with the rated load weight to calculate the load error, and accurately corrects the real-time motor speed to ensure that the motor can still maintain the best operating state when the load changes. On the basis of load correction, the environmental adjustment unit comprehensively considers the lifting height and external environmental data of the crane. Through these two adjustments, the motor correction speed is closer to the actual operating requirements, which helps to reduce energy consumption, extend the service life of the crane, and reduce maintenance costs.

[0107] Those skilled in the art will appreciate that the embodiments of the present application may provide methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. Energy saving method of crane frequency conversion control, It is characterized in that include: Acquire the real-time motor speed of the crane, and determine the rated load weight of the crane according to the real-time motor speed; Acquire the actual load weight of the crane, calculate the load error according to the actual load weight and the rated load weight, and correct the real-time motor speed according to the load error to obtain the motor correction speed; After the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is acquired, and the motor correction speed is adjusted once according to the lifting height; After the motor speed is adjusted once according to the lifting height, external environment data is acquired, and the motor correction speed is adjusted twice according to the external environment data, and the motor correction speed after the second adjustment is used as the motor operating speed.

2. The crane variable frequency control energy saving method according to claim 1, It is characterized in that The method comprises: obtaining the actual load weight of the crane, calculating a load error according to the actual load weight and the rated load weight, and correcting the real-time motor speed according to the load error to obtain the corrected motor speed, including: The rated load weight is recorded as Wt, and the actual load weight is recorded as Wr; The load error is recorded as W, W = Wt-Wr; A load difference correction threshold Wa is preset, and Wa>0; When -Wa<W<Wa, it is determined that the real-time motor speed is not corrected according to the load error, and the real-time motor speed is used as the motor correction speed; When W≤-Wa or W≥Wa, it is determined to correct the real-time motor speed according to the load error.

3. The crane variable frequency control energy saving method according to claim 2, It is characterized in that When W≤-Wa or W≥Wa, it is determined that the real-time motor speed is corrected according to the load error, including: Preset the speed control gain Kp; Calculate the speed correction amount ΔW according to the speed control gain Kp and the load error W, ΔW=Kp×W; The real-time motor speed is recorded as V; The real-time motor speed V is adjusted according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, where Va=V+ΔW.

4. The crane variable frequency control energy saving method according to claim 3, It is characterized in that After adjusting the real-time motor speed V according to the speed correction amount ΔW to obtain the adjusted real-time motor speed Va, the method further includes: Preset the maximum motor speed threshold Vmax and the minimum motor speed threshold Vmin; When Vmin<Va<Vmax, the adjusted real-time motor speed Va is used as the motor correction speed; When Va≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed; When Va≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

5. The crane variable frequency control energy saving method according to claim 4, It is characterized in that After the real-time motor speed is corrected according to the load error to obtain the motor correction speed, the lifting height of the crane is acquired, and the motor correction speed is adjusted once according to the lifting height, including: The motor correction speed is recorded as Vx; The lifting height is recorded as H; A first preset lifting height threshold H1 and a second preset lifting height threshold H2 are preset, and H1>H2; a first preset height adjustment coefficient h1, a second preset height adjustment coefficient h2, and a third preset height adjustment coefficient h3 are preset, and 0.9<h1<h2<h3<1.1, h2=1; When H>H1, the first preset height adjustment coefficient h1 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h1; When H1≥H>H2, the second preset height adjustment coefficient h2 is selected to adjust the motor correction speed Vx once, and the motor correction speed after the adjustment is Vx*h2; When H3≥H, the third preset height adjustment coefficient h3 is selected to perform a one-time adjustment on the motor correction speed Vx, and the motor correction speed after the one-time adjustment is Vx*h3.

6. The crane variable frequency control energy saving method according to claim 5, It is characterized in that The external environment data includes real-time ambient temperature and real-time ambient wind speed.

7. The crane variable frequency control energy saving method according to claim 6, It is characterized in that After selecting the i-th preset height adjustment coefficient hi to adjust the motor correction speed Vx once, i=1, 2, 3, and obtaining the motor correction speed Vx*hi after the adjustment, the method further includes: Obtaining the real-time temperature of the environment, and recording the real-time temperature of the environment as T; Obtain the real-time wind speed of the environment, and record the real-time wind speed of the environment as F; Preset the maximum temperature threshold Tmax and the maximum wind speed threshold Fmax; A first preset environment adjustment coefficient n1, a second preset environment adjustment coefficient n2 and a third preset environment adjustment coefficient n3 are preset, and 0.8<n1<n2<n3, n3=1; When T≤Tmax and F≤Fmax, the third preset environment adjustment coefficient n3 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n3; When T>Tmax or F>Fmax, the second preset environment adjustment coefficient n2 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after secondary adjustment is Vx*hi*n2; When T>Tmax and F>Fmax, the first preset environment adjustment coefficient n1 is selected to perform secondary adjustment on the motor correction speed Vx, and the motor correction speed after the secondary adjustment is Vx*hi*n1.

8. The crane variable frequency control energy saving method according to claim 7, It is characterized in that After selecting the i-th preset environment adjustment coefficient ni to perform secondary adjustment on the motor correction speed Vx, i=1, 2, 3, and obtaining the motor correction speed after secondary adjustment as Vx*hi*ni, the method further includes: When Vmin<Vx*hi*ni<Vmax, the motor correction speed Vx*hi*ni after secondary adjustment is used as the motor running speed; When Vx*hi*ni≤Vmin, the motor speed minimum threshold Vmin is used as the motor correction speed; When Vx*hi*ni≥Vmax, the maximum threshold value Vmax of the motor speed is used as the motor correction speed.

9. Crane frequency conversion control energy saving system, It is characterized in that The crane variable frequency control energy saving method according to any one of claims 1 to 8 is applied, comprising: A data acquisition unit, used for acquiring a real-time motor speed of the crane, and determining a rated load weight of the crane according to the real-time motor speed; A load correction unit, used for obtaining the actual load weight of the crane, calculating a load error according to the actual load weight and the rated load weight, and correcting the real-time motor speed according to the load error to obtain a motor correction speed; The environment adjustment unit is used to obtain the lifting height of the crane after the load correction unit corrects the real-time motor speed according to the load error to obtain the motor correction speed, and adjust the motor correction speed once according to the lifting height; after the motor speed is adjusted once according to the lifting height, obtain external environment data, make a second adjustment to the motor correction speed according to the external environment data, and use the motor correction speed after the second adjustment as the motor operating speed.

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