Redundant variable-frequency driving system of ultra-large ladle crane

Abstract

The invention provides a redundant variable-frequency driving system of an ultra-large ladle crane, which comprises a rectified feedback system, a main lifting driving system, an auxiliary lifting driving system, a main trolley driving system, an auxiliary trolley driving system and a cart driving system which work independently and respectively drive corresponding mechanisms to operate. The system has the characteristics of fault emergency switching and long-term normal work, the redundancy coverage range is more comprehensive, the reliability of the driving system is higher, the equipment fault shutdown is avoided, and the production operation continuity is ensured. In the system, the capacity of the main lifting motor, the capacity of the main lifting inverter and the capacity of the rectification feedback unit can be reduced by 30%, the equipment cost is obviously reduced, and the electric control system is more energy-saving. The main hoisting mechanism adopts a staggered starting mode, the starting current is reduced by 25%, and the impact on a power supply grid is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of variable frequency drive systems, and in particular to a redundant variable frequency drive system for an ultra-large casting crane. Background Art

[0002] With the elimination of backward production capacity and the green, low-carbon and high-quality development of steel enterprises, the demand for the lifting capacity of casting cranes continues to increase. The market demand for super-large casting cranes of 500t and above is increasing, and the requirements for machine models are also shifting from single type to diversified. In addition, casting cranes are used in harsh environments and have high working levels; they are used to lift liquid molten metal and have high safety performance. Therefore, the drive system solution of the casting crane is required to be mature, reliable, and have redundant backup functions to meet the needs of long-term normal operation of the crane.

[0003] At present, although some casting cranes have been designed for emergency switching (such as Figure 1 As shown in the figure, it only realizes the short-term emergency use of the mechanism and cannot meet the long-term normal operation; the scheme of "emergency switching of the trolley inverter to drive the auxiliary lifting motor" and "emergency switching of the main trolley inverter to drive the auxiliary trolley motor" is adopted. The drive systems of each mechanism affect each other, the redundant backup coverage is small, and there are disadvantages such as complex switching circuits, high failure rate, and poor practicality. In addition, only the emergency work of the main lifting mechanism with a large reducer model is studied, and the redundant design of the planetary reducer model is not considered. Summary of the invention

[0004] According to the technical problems mentioned in the above background technology, a redundant variable frequency drive system for a super large casting crane is provided. The present invention provides a redundant variable frequency drive system for a super large casting crane (such as Figure 2 As shown in the figure, it is composed of a rectifier feedback system, a main hoisting drive system, a secondary hoisting drive system, a main trolley drive system, a secondary trolley drive system and a trolley drive system, which realizes the complete, online redundant variable frequency drive system for emergency switching of the foundry crane and long-term normal operation, and develops a redundant design for the main hoisting planetary reducer model of the super-large foundry crane. It improves the practicality and reliability of the electronic control system, avoids equipment failure and downtime, and ensures the production efficiency of the enterprise.

[0005] The technical means adopted by the present invention are as follows:

[0006] A redundant variable frequency drive system for an ultra-large casting crane, comprising:

[0007] The rectifier feedback system, main hoisting drive system, auxiliary hoisting drive system, main trolley drive system, auxiliary trolley drive system and trolley drive system, each system works independently and drives the corresponding mechanism to operate respectively;

[0008] The rectification feedback system provides power supply and regenerative energy feedback for all drive systems; the rectification feedback system includes: a first rectification feedback system and a second rectification feedback system; the configurations of the first rectification feedback system and the second rectification feedback system are exactly the same; under normal circumstances, the first rectification feedback system and the second rectification feedback system work independently; when one of the systems fails, the other system supplies power to all drive systems to ensure that the equipment continues to operate;

[0009] The main lifting drive system, auxiliary lifting drive system, main trolley drive system, auxiliary trolley drive system and trolley drive system work independently and drive the corresponding mechanisms to operate respectively.

[0010] Furthermore, the first set of rectification and feedback system includes: rectification and feedback unit U11, incoming circuit breaker Q11, outputting the first common DC bus after passing through the isolating switch Q01; the first set of main hoisting drive system, the auxiliary hoisting drive system, the first set of main trolley and the first set of trolley drive system are connected to the first common DC bus through their respective DC isolating switches to obtain power supply;

[0011] The second rectifier feedback system includes: a rectifier feedback unit U12, an incoming circuit breaker Q12, and a second common DC bus output after passing through the isolating switch Q02; the second main hoisting drive system, the auxiliary trolley drive system, the second main trolley drive system and the second trolley drive system are connected to the second common DC bus through their respective DC isolating switches to obtain power supply.

[0012] Furthermore, the rectification feedback system is an actively regulated rectification unit, and the capacity of each rectification unit can satisfy the normal operation of both the main hoisting mechanism and the trolley mechanism at the same time.

[0013] Furthermore, the main lifting mechanism adopts a planetary reducer model; the main lifting drive system includes: a first drive system and a second drive system, the two systems have exactly the same configuration and jointly drive the main lifting planetary reducer;

[0014] The first drive system includes: inverter U21, inverter U22, inverter U23 drive motor M21, motor M22; the input ends of the three inverters are connected to the first common DC bus through isolating switch Q21, isolating switch Q22, isolating switch Q23, and the output ends of the inverters are connected to the two motors through switching switch Q211, switching switch Q221, switching switch Q231; when inverter U21 or inverter U22 fails, switch to standby inverter U23 to ensure the normal operation of the main lifting mechanism;

[0015] The second drive system includes: inverter U24, inverter U25, inverter U26 drive motor M23, motor M24; the input ends of the three inverters are connected to the second common DC bus through isolating switch Q24, isolating switch Q25, isolating switch Q26, and the output ends of the three inverters are connected to two motors through switching switch Q241, switching switch Q251, switching switch Q261; when inverter U24 or inverter U25 fails, switch to the standby inverter U26 to ensure the normal operation of the main lifting mechanism.

[0016] Furthermore, the main hoisting drive system adopts a staggered starting method, starting one group of motors first, and when the motors reach the rated speed, starting another group of motors.

[0017] Furthermore, the auxiliary lifting drive system includes: inverter U31, inverter U32 drives motor M31; the input ends of the two inverters are connected to the first common DC bus via isolating switches Q31 and Q32, and the output ends of the two inverters are connected to the motor via switching switch Q33; during normal operation, it is driven by one inverter; when this inverter fails, it switches to another inverter to ensure that the mechanism can continue to operate normally.

[0018] Further, the main trolley driving system includes: a first driving system and a second driving system;

[0019] The first drive system includes: an inverter U41 drives a motor M41 and a motor M42; the input end of the inverter is connected to the first common DC bus through an isolating switch Q41, and the output end of the inverter is connected to the two motors through a motor circuit breaker Q411 and a motor circuit breaker Q412;

[0020] The second drive system includes: an inverter U42 drives a motor M43 and a motor M44; the input end of the inverter is connected to the second common DC bus through an isolating switch Q42, and the output end of the inverter is connected to two motors through a motor circuit breaker Q421 and a motor circuit breaker Q422;

[0021] The capacity of each inverter is sufficient for the normal operation of the mechanism. Under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the entire mechanism to continue operating.

[0022] Furthermore, the auxiliary trolley drive system includes: inverter U51, inverter U52 drives the motor M51; the input ends of the two inverters are connected to the second common DC bus via isolating switches Q51 and Q52, and the output ends of the two inverters are connected to the motor via switching switch Q53; during normal operation, it is driven by one inverter; when this inverter fails, it switches to another inverter to ensure that the mechanism can continue to operate normally.

[0023] Further, the vehicle driving system includes: a first driving system and a second driving system;

[0024] The first drive system includes: an inverter U61 drives a motor M61 and a motor M62; the input end of the inverter is connected to the first common DC bus through an isolating switch Q61, and the output end of the inverter is connected to the two motors through a motor circuit breaker Q611 and a motor circuit breaker Q612;

[0025] The second drive system includes: an inverter U62 drives a motor M63 and a motor M64; the input end of the inverter is connected to the second common DC bus through an isolating switch Q62, and the output end of the inverter is connected to two motors through a motor circuit breaker Q621 and a motor circuit breaker Q622;

[0026] The capacity of each inverter is sufficient for the normal operation of the mechanism. Under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the entire mechanism to continue normal operation.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The system of the present invention has the characteristics of emergency switching in case of failure and long-term normal operation, the redundancy coverage is more comprehensive, the driving system reliability is higher, the equipment failure shutdown is avoided, and the continuity of production operation is ensured.

[0029] In the system of the present invention, the capacity of the main hoisting motor, the main hoisting inverter and the rectifier unit can be reduced by 30%, the equipment cost is significantly reduced, and the electric control system is more energy-efficient. The main hoisting mechanism adopts a staggered starting mode, and the starting current is reduced by 25%, which greatly reduces the impact on the power supply network. The main trolley and trolley mechanisms have two inverters. Under normal circumstances, the two inverters are used at the same time; when one inverter fails, the other inverter drives the mechanism to continue normal operation, which improves the practicality of the system.

[0030] In the present invention, the auxiliary lifting and auxiliary trolley mechanisms each have a working inverter and a standby inverter. The redundancy scheme is reliable, the failure rate is low, and the influence of the failure of the mechanism on other mechanisms is avoided, thereby improving the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 This is the fault redundancy system diagram of the existing casting crane variable frequency speed regulation.

[0033] Figure 2 This is a diagram of a redundant frequency conversion drive system for an ultra-large casting crane according to the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] like Figure 2 As shown, the present invention provides a redundant variable frequency drive system for an ultra-large casting crane, comprising a rectifier feedback system, a main lifting drive system, an auxiliary lifting drive system, a main trolley drive system, an auxiliary trolley drive system and a trolley drive system.

[0037] The rectifier feedback system consists of a first rectifier feedback system 1-1 and a second rectifier feedback system 1-2. The first rectifier feedback system includes a rectifier feedback unit U11, an incoming circuit breaker Q11, and after passing through the isolating switch Q01, outputs the first common DC bus to provide DC power supply for the first main hoisting drive system 2-1, the auxiliary hoisting drive system 3, the first main trolley drive system 4-1, and the first trolley drive system 6-1; the second rectifier feedback system includes a rectifier feedback unit U12, an incoming circuit breaker Q12, and after passing through the isolating switch Q02, outputs the second common DC bus to provide DC power supply for the second main hoisting drive system 2-2, the auxiliary trolley drive system 5, the second main trolley drive system 4-2, and the second trolley drive system 6-2. The rectification and feedback system provides power supply and regenerative energy feedback for all drive systems; the rectification and feedback system includes: a first rectification and feedback system and a second rectification and feedback system; the configurations of the first rectification and feedback system and the second rectification and feedback system are exactly the same; under normal circumstances, the first rectification and feedback system and the second rectification and feedback system work independently; when one of the systems fails, the other system supplies power to all drive systems to ensure that the equipment continues to operate.

[0038] The rectifier feedback device should use an active regulating rectifier unit. The capacity of each rectifier unit can meet the normal operation of the main hoist and trolley mechanisms at the same time. Under normal circumstances, two rectifier feedback units are used at the same time. When one of the rectifier units fails, it will be cut off, and the busbar connection switch Q03 will be closed. The other rectifier unit will supply power to the two common DC buses at the same time to ensure that the crane continues to operate normally and realize the redundant standby function.

[0039] The main lifting mechanism adopts a large reducer model, and the fault redundancy protection system and redundant protection method of the casting crane variable frequency speed regulation (patent number: CN102167260B) have been studied in detail, which will not be repeated here. The present invention is mainly based on the main lifting mechanism of the super-large casting crane adopting a planetary reducer model.

[0040] The main hoisting mechanism uses four motors, but its drive system can be divided into two inverters, four inverters or no spare inverter, etc., but these modifications do not deviate from the scope of the technical solution of the present invention. This embodiment preferably takes four working inverters and two spare inverters as an example to describe the technical solution of the main hoisting redundant drive system.

[0041] The main hoisting drive system consists of a first drive system 2-1 and a second drive system 2-2. The first drive system includes two working inverters U21 and U22, a standby inverter U23, disconnectors Q21, Q22, Q23, and switching switches Q211, Q221, and Q231, which are used to drive motors M21 and M22. When a working inverter fails, it switches to the standby inverter to ensure the normal operation of the main hoisting mechanism; the second drive system includes two working inverters U24 and U25, a standby inverter U26, disconnectors Q24, Q25, and Q26, and switching switches Q241, Q251, and Q261, which are used to drive motors M23 and M24, and also have redundant switching functions.

[0042] The main lifting mechanism adopts a planetary reducer model; the main lifting drive system includes: a first drive system and a second drive system, the two systems have exactly the same configuration and jointly drive the main lifting planetary reducer;

[0043] The first drive system includes: inverter U21, inverter U22, inverter U23 drive motor M21, motor M22; the input ends of the three inverters are connected to the first common DC bus through isolating switch Q21, isolating switch Q22, isolating switch Q23, and the output ends of the inverters are connected to the two motors through switching switch Q211, switching switch Q221, switching switch Q231; when inverter U21 or inverter U22 fails, switch to standby inverter U23 to ensure the normal operation of the main lifting mechanism;

[0044] The second drive system includes: inverter U24, inverter U25, inverter U26 drive motor M23, motor M24; the input ends of the three inverters are connected to the second common DC bus through isolating switch Q24, isolating switch Q25, isolating switch Q26, and the output ends of the three inverters are connected to two motors through switching switch Q241, switching switch Q251, switching switch Q261; when inverter U24 or inverter U25 fails, switch to the standby inverter U26 to ensure the normal operation of the main lifting mechanism.

[0045] The main hoisting drive system adopts a staggered starting method, starting one group of motors first, and then starting another group of motors when the motor reaches the rated speed.

[0046] In addition to maintaining the inherent single-machine, half-speed, full-load, and long-term operation characteristics of the planetary reducer, this technical solution is equipped with independent inverters for the four motors. When a working inverter fails, it can quickly switch to the backup inverter to ensure that the mechanism works normally at full load and full speed. The redundant backup protection range is more comprehensive, greatly improving the reliability of the drive system, avoiding equipment failure and downtime, and ensuring the continuity of production operations.

[0047] Compared with the large reducer model, the capacity of the main hoisting motor, main hoisting inverter and rectifier unit can be reduced by 30%, the equipment cost is significantly reduced, and the electric control system is more energy-efficient. In addition, the staggered starting method is adopted, one group of motors is started first, and when the motor reaches the rated speed, another group of motors is started, the starting current is reduced by 25%, greatly reducing the impact on the power supply grid.

[0048] In addition, the planetary reducer has a double degree of freedom characteristic, and the entire transmission chain needs to be monitored in real time (refer to the Chinese patent applications with application numbers CN200510078243 and CN201410698220), and a safety brake is installed on the reel. And because the planetary reducer rotates at a high speed, the bearings are prone to heat, and an additional lubricating oil external circulation cooling system needs to be designed.

[0049] The auxiliary lifting drive system 2 is composed of a working inverter U31, a standby inverter U32, isolating switches Q31, Q32, and a switching switch Q33, and is used to drive the motor M31. When the working inverter fails, it can quickly switch to the standby inverter. Compared with the prior art "emergency switching of the trolley inverter to drive the auxiliary lifting motor", the redundant standby solution is reliable, has a low failure rate, and avoids the impact on the trolley mechanism due to the failure of the auxiliary lifting inverter. The auxiliary lifting drive system includes: inverter U31 and inverter U32 drive a motor M31; the input ends of the two inverters are connected to the first common DC bus through isolating switches Q31 and Q32, and the output ends of the two inverters are connected to the motor through switching switch Q33; during normal operation, it is driven by one inverter; when this inverter fails, it switches to another inverter to ensure that the mechanism can continue to work normally.

[0050] The main trolley drive system consists of the first drive system 4-1 and the second drive system 4-2. The first drive system consists of inverter U41, disconnector Q41, motor circuit breakers Q411 and Q412, and is used to drive motors M41 and M42; the second drive system consists of inverter U42, disconnector Q42, motor circuit breakers Q421 and Q422, and is used to drive motors M43 and M44. The capacity of each inverter meets the normal operation of the mechanism. Under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the entire mechanism to continue to operate normally.

[0051] The auxiliary trolley driving system 5 is composed of a working inverter U51, a standby inverter U52, isolating switches Q51, Q52, and a switching switch Q53, and is used to drive the motor M51. When the working inverter fails, it can quickly switch to the standby inverter. Compared with the prior art "main trolley inverter emergency switching to drive the auxiliary trolley motor" solution, it has reliable performance, low failure rate, and is independently configured with the main trolley mechanism without affecting each other.

[0052] The trolley drive system consists of the first drive system 6-1 and the second drive system 6-2. The first drive system consists of inverter U61, disconnector Q61, motor circuit breakers Q611 and Q612, which are used to drive motors M61 and M62; the second drive system consists of inverter U62, disconnector Q62, motor circuit breakers Q621 and Q462, which are used to drive motors M63 and M64. The capacity of each inverter meets the normal operation of the mechanism. Under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the trolley mechanism to continue normal operation to ensure production continuity.

[0053] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0054] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0055] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0056] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0057] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0058] If the integrated unit is implemented in the form of 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 the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0059] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A redundant variable frequency drive system for an ultra-large casting crane, characterized in that: include: The rectifier feedback system, main hoisting drive system, auxiliary hoisting drive system, main trolley drive system, auxiliary trolley drive system and trolley drive system, each system works independently and drives the corresponding mechanism to operate respectively; The rectification feedback system provides power supply and regenerative energy feedback for all drive systems; The rectification feedback system comprises: a first rectification feedback system and a second rectification feedback system; The configurations of the first set of rectification feedback system and the second set of rectification feedback system are exactly the same; under normal circumstances, the first set of rectification feedback system and the second set of rectification feedback system work independently; when one of the systems fails, the other system supplies power to all drive systems to ensure that the equipment continues to operate; The main lifting drive system, auxiliary lifting drive system, main trolley drive system, auxiliary trolley drive system and trolley drive system work independently and drive the corresponding mechanisms to operate respectively.

2. The redundant variable frequency drive system for a super large casting crane according to claim 1 is characterized in that: The first set of rectification and feedback system includes: rectification and feedback unit U11, incoming circuit breaker Q11, outputting the first common DC bus after passing through the isolating switch Q01; the first set of main hoisting drive system, auxiliary hoisting drive system, the first set of main trolley and the first set of trolley drive system are connected to the first common DC bus through their respective DC isolating switches to obtain power supply; The second rectifier feedback system includes: a rectifier feedback unit U12, an incoming circuit breaker Q12, and a second common DC bus output after passing through the isolating switch Q02; the second main hoisting drive system, the auxiliary trolley drive system, the second main trolley drive system and the second trolley drive system are connected to the second common DC bus through their respective DC isolating switches to obtain power supply.

3. The redundant variable frequency drive system for a super large casting crane according to claim 1 is characterized in that: The rectifier feedback system is an actively regulated rectifier unit, and the capacity of each rectifier unit can meet the normal operation of the main hoisting and trolley mechanisms at the same time.

4. The redundant variable frequency drive system for a super large casting crane according to claim 1 is characterized in that: The main lifting mechanism adopts a planetary reducer model; The main lifting drive system includes: a first drive system and a second drive system, the two systems have exactly the same configuration and jointly drive the main lifting planetary reducer; The first drive system includes: inverter U21, inverter U22, inverter U23 drive motor M21, motor M22; the input ends of the three inverters are connected to the first common DC bus through isolating switch Q21, isolating switch Q22, isolating switch Q23, and the output ends of the inverters are connected to the two motors through switching switch Q211, switching switch Q221, switching switch Q231; when inverter U21 or inverter U22 fails, switch to standby inverter U23 to ensure the normal operation of the main lifting mechanism; The second drive system includes: inverter U24, inverter U25, inverter U26 drive motor M23, motor M24; the input ends of the three inverters are connected to the second common DC bus through isolating switch Q24, isolating switch Q25, isolating switch Q26, and the output ends of the three inverters are connected to two motors through switching switch Q241, switching switch Q251, switching switch Q261; when inverter U24 or inverter U25 fails, switch to the standby inverter U26 to ensure the normal operation of the main lifting mechanism.

5. The redundant variable frequency drive system for a super large casting crane according to claim 1 is characterized in that: The main hoisting drive system adopts a staggered starting method, starting one group of motors first, and then starting another group of motors when the motor reaches the rated speed.

6. The redundant variable frequency drive system for a super large casting crane according to claim 1, characterized in that: The auxiliary lifting drive system includes: inverter U31, inverter U32 driving motor M31; the input ends of the two inverters are connected to the first common DC bus via isolating switches Q31 and Q32, and the output ends of the two inverters are connected to the motor via switching switch Q33; during normal operation, it is driven by one inverter; when this inverter fails, it switches to another inverter to ensure that the mechanism can continue to operate normally.

7. The redundant variable frequency drive system for a super large casting crane according to claim 1, characterized in that: The main trolley driving system includes: a first driving system and a second driving system; The first drive system includes: an inverter U41 drives a motor M41 and a motor M42; the input end of the inverter is connected to the first common DC bus through an isolating switch Q41, and the output end of the inverter is connected to the two motors through a motor circuit breaker Q411 and a motor circuit breaker Q412; The second drive system includes: an inverter U42 drives a motor M43 and a motor M44; the input end of the inverter is connected to the second common DC bus through an isolating switch Q42, and the output end of the inverter is connected to two motors through a motor circuit breaker Q421 and a motor circuit breaker Q422; The capacity of each inverter is sufficient for the normal operation of the mechanism. Under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the entire mechanism to continue operating.

8. The redundant variable frequency drive system for a super large casting crane according to claim 1, characterized in that: The auxiliary trolley driving system includes: inverter U51, inverter U52 drives motor M51; the input ends of the two inverters are connected to the second common DC bus through isolating switches Q51 and Q52, and the output ends of the two inverters are connected to the motor through switching switch Q53; during normal operation, it is driven by one inverter; when this inverter fails, it switches to another inverter to ensure that the mechanism can continue to operate normally.

9. The redundant variable frequency drive system for a super-large casting crane according to claim 1, characterized in that: The vehicle driving system comprises: a first driving system and a second driving system; The first drive system includes: an inverter U61 drives a motor M61 and a motor M62; the input end of the inverter is connected to the first common DC bus through an isolating switch Q61, and the output end of the inverter is connected to the two motors through a motor circuit breaker Q611 and a motor circuit breaker Q612; The second drive system includes: an inverter U62 drives a motor M63 and a motor M64; the input end of the inverter is connected to the second common DC bus through an isolating switch Q62, and the output end of the inverter is connected to two motors through a motor circuit breaker Q621 and a motor circuit breaker Q622; The capacity of each inverter is sufficient for the normal operation of the mechanism; under normal circumstances, two inverters are used at the same time; when one inverter fails, the other inverter drives the entire mechanism to continue operating.

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