Cracking furnace fan motor common direct current bus frequency conversion system

Abstract

The utility model discloses a cracking furnace fan motor common DC bus frequency conversion system. The system comprises two groups of voltage transformation rectification units which are redundant to each other, a plurality of inversion modules and a DC bus. Each group of voltage transformation and rectification unit comprises a voltage transformation module and a rectification module, the input end of the voltage transformation module is connected with the alternating current bus, the output end of the voltage transformation module is connected with the input end of the rectification module, the output end of the rectification module is connected with the direct current bus, and the rectification module is used for setting alternating current into direct current; the input end of each inversion module is connected with the direct-current bus, the output end of each inversion module is connected with a motor of a cracking furnace fan, and the inversion modules are used for converting energy of the direct-current bus into alternating-current output with different voltages and different frequencies and providing required energy and rotating speed regulation control for operation of the motor. According to the utility model, the fault rate of equipment can be reduced, the operation reliability of the frequency converter is guaranteed, and the expandability of the frequency conversion system is improved.

Description

Technical Field

[0001] The utility model belongs to the field of petrochemical industry, and more specifically relates to a frequency conversion system for a cracking furnace fan motor sharing a DC bus. Background Art

[0002] In the petrochemical industry, the cracking furnace is the core key equipment of the ethylene plant, and its safe operation directly affects the normal production of the ethylene plant. Usually, the ethylene plant is equipped with multiple cracking furnaces, each furnace is equipped with a high-power fan, and the fan usually adopts variable frequency speed regulation.

[0003] At present, fans all adopt a one-to-one variable frequency drive solution (single transmission mode), which is characterized by one-to-one drive, and the inverter and other loads are powered by the same low-voltage system. Its advantages are:

[0004] 1. After long-term practice, there are a variety of mature products with reliable quality to choose from;

[0005] 2. In single transmission mode, the equipment has a simple and standardized structure, and the internal parts can be repaired and replaced;

[0006] 3. All enterprises have been using it for a long time and have certain experience in use and maintenance.

[0007] Its disadvantages are:

[0008] 1. Since it is a single machine operation, it cannot solve the problem of failure of each subsystem inside the equipment when the single machine is running. The equipment failure rate depends on the highest failure rate of each subsystem, that is, any subsystem damage will affect the operation of the inverter.

[0009] 2. The reliability of the inverter operation is not guaranteed from the system level.

[0010] 3. Poor expandability and adaptability. Utility Model Content

[0011] The utility model aims to propose a cracking furnace fan motor common DC bus frequency conversion system to reduce equipment failure rate, ensure the reliability of frequency converter operation, and improve the scalability of the frequency conversion system.

[0012] To achieve the above purpose, the utility model proposes a cracking furnace fan motor common DC bus frequency conversion system, including: two sets of mutually redundant transformer rectifier units, multiple inverter modules and a DC bus;

[0013] Each group of transformer and rectifier units includes a transformer module and a rectifier module, the input end of the transformer module is connected to the AC bus, the output end of the transformer module is connected to the input end of the rectifier module, the output end of the rectifier module is connected to the DC bus, and the rectifier module is used to rectify the AC power into DC power;

[0014] The input end of each inverter module is connected to the DC bus, and the output end of each inverter module is connected to the motor of a cracking furnace fan. The inverter module is used to convert the energy of the DC bus into AC output of different voltages and frequencies to provide the required energy and speed regulation control for the operation of the motor.

[0015] Optionally, the transformer module includes a 24-pulse rectifier transformer, and the rectifier module includes a rectifier;

[0016] The input end of the 24-pulse rectifier transformer is connected to the AC bus, and the output end of the 24-pulse rectifier transformer is divided into four paths connected to the input end of the rectifier.

[0017] Optionally, the voltage transformation module includes a transformer, and the rectifier module includes an AFE controlled rectifier;

[0018] The input end of the transformer is connected to the AC bus, and the output end of the transformer is connected to the input end of the AFE controlled rectifier.

[0019] Optionally, the inverter module includes an inverter, an input end of the inverter is connected to the DC bus, and an output end of the inverter is connected to an input end of the motor.

[0020] Optionally, the inverter module includes two inverters, the input ends of the two inverters are respectively connected to the DC bus, the input ends of the two inverters are respectively connected to the input ends of the motor, and the two inverters are redundant.

[0021] Optionally, an auxiliary power supply module is also included, and the auxiliary power supply module is connected to the DC bus. The auxiliary power supply module is used to provide energy support for the DC bus to meet the anti-power shaking requirement.

[0022] Optionally, the auxiliary power supply module includes an energy storage device and a DC / DC converter, and the energy storage device is connected to the DC bus through the DC / DC converter.

[0023] Optionally, the energy storage device includes at least one supercapacitor and / or at least one battery pack.

[0024] The beneficial effects of the utility model are:

[0025] The utility model discloses a cracking furnace fan motor common DC bus frequency conversion system, which adopts two sets of independent modular transformer and rectifier units to supply power to the DC bus segment, forming a dual-power supply line single bus structure, and provides AC output of corresponding frequency and voltage for the motors of multiple cracking furnace fans through multiple inverter modules, so as to meet the frequency conversion requirements of the fan motors, solve the problem of common rectification, DC, inverter and the like of frequency converters of multiple cracking furnace fan motors, and improve the reliability of the frequency converter operation from the system link. At the same time, the system can be flexibly configured by module according to the specific conditions of the project during use, so as to improve the expansibility and flexibility of the frequency conversion system.

[0026] The system of the present invention has other characteristics and advantages, which will be obvious from the drawings and subsequent specific embodiments incorporated herein, or will be described in detail in the drawings and subsequent specific embodiments incorporated herein, which together are used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0028] Figure 1 A structural schematic diagram of a cracking furnace fan motor common DC bus frequency conversion system in Example 1 of the utility model is shown.

[0029] Figure 2 A structural schematic diagram of a cracking furnace fan motor common DC bus frequency conversion system in Example 2 of the utility model is shown. DETAILED DESCRIPTION

[0030] The variable frequency speed regulation drive principle of the frequency converter is that the rectifier unit converts AC power into DC power, and then converts DC power into controllable AC power through the inverter to achieve the purpose of frequency regulation drive.

[0031] At present, the petrochemical industry system widely adopts the single transmission solution. The technical characteristics of the single transmission solution are one-to-one, no redundancy, and the inverter failure will directly affect the operation of the fan.

[0032] In addition to the single transmission mode, there is also a multi-machine drive technology. It consists of a rectifier module and multiple inverter units. Its characteristics are low cost and one (rectifier) ​​with multiple (inverter) operation through the DC bus. The multi-transmission mode is mostly used in industries such as metallurgy and shipbuilding that do not require high load levels. It does not require high power supply reliability and is not suitable for high-risk environments in petrochemicals.

[0033] Aiming at the characteristics of petrochemical industry, the utility model proposes a cracking furnace fan motor common DC bus frequency conversion system, which can satisfactorily solve the power supply reliability problem of multi-transmission inverter and improve the system flexibility.

[0034] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0035] Example 1

[0036] like Figure 1 As shown, this embodiment provides a cracking furnace fan motor common DC bus frequency conversion system, including: two sets of mutually redundant transformer and rectifier units, multiple inverter modules 5 and a DC bus 4;

[0037] Each group of transformer and rectifier units includes a transformer module 2 and a rectifier module 3. The input end of the transformer module 2 is connected to the AC bus 1, the output end of the transformer module 2 is connected to the input end of the rectifier module 3, and the output end of the rectifier module 3 is connected to the DC bus 4. The rectifier module 3 is used to convert AC power into DC power.

[0038] The input end of each inverter module 5 is connected to the DC bus 4, and the output end of each inverter module 5 is connected to the motor 6 of a cracking furnace fan. The inverter module 5 is used to convert the energy of the DC bus 4 into AC outputs of different voltages and frequencies, providing the required energy and speed regulation control for the operation of the motor 6.

[0039] In this embodiment, the transformer module 2 includes a 24-pulse rectifier transformer, and the rectifier module 3 includes a rectifier;

[0040] The input end of the 24-pulse rectifier transformer is connected to the AC bus 1, and the output end of the 24-pulse rectifier transformer is divided into 4 paths connected to the input end of the rectifier.

[0041] Specifically, the system adopts dual power supply lines. The transformer adopts two 24-pulse rectifier transformers running in parallel, and the two 24-pulse rectifier transformers each divide 4 lines to power the rectifier. After 24-pulse rectification, the grid-side harmonic content is less than 5%; two sets of basic rectifiers respectively adjust the AC voltage to DC voltage and jointly establish a DC bus 4. The rectifier in this embodiment includes a three-phase fuse, a diode, a filter circuit, an access switch, etc.

[0042] In this embodiment, a control switch 9 is further provided between the transformer module 2 and the inverter module 5 of the two sets of transformer and rectifier units. The control switch 9 may be a contactor or a relay. Through the control switch 9, the two rectifiers connected to the two sections of the AC bus 1 can provide redundant power to the DC bus 4, and both can provide energy to the DC bus 4.

[0043] Preferably, the AC bus 1 in this embodiment provides 10KV three-phase AC power, and the rated capacity of the 24-pulse rectifier transformer is 2000KVA and the rated voltage is 10 / 0.69KV. In other embodiments, the AC bus 1 may also be an AC bus of other high voltage levels, and a 24-pulse rectifier transformer of other rated capacity and rated voltage may also be used according to requirements.

[0044] In this embodiment, the inverter module 5 includes an inverter, an input end of the inverter is connected to the DC bus 4 , and an output end of the inverter is connected to an input end of the motor 6 .

[0045] Specifically, the inverter converts the energy of the DC bus 4 into corresponding AC output according to the actual needs of the motor 6, and provides the required energy and speed regulation for the operation of the motor 6. This embodiment uses one inverter. In other embodiments, the inverter module 5 can also be configured in the form of dual-machine redundancy according to engineering requirements. That is, the inverter module 5 includes two inverters, the input ends of the two inverters are respectively connected to the DC bus 4, and the input ends of the two inverters are respectively connected to the input ends of the motor 6, and the two inverters are redundant to each other. The inverter mainly includes two fuses, multiple power switches (IGBT or MOSFET), a drive circuit, a filter, and a control switch.

[0046] In this embodiment, the system further includes a control unit, which is used to adjust the output frequency and voltage of the inverter according to the parameters set by the user and the feedback signal, so as to achieve precise control of the motor 6.

[0047] In this embodiment, the system further includes an auxiliary power supply module, which is connected to the DC bus 4 and is used to provide energy support for the DC bus 4 to meet the anti-power shaking requirement.

[0048] The auxiliary power supply module includes an energy storage device 7 and a DC / DC converter 8, and the energy storage device 7 is connected to the DC bus 4 through the DC / DC converter 8. Optionally, the energy storage device 7 includes at least one supercapacitor and / or at least one battery pack. The energy storage device 7 in this embodiment includes one or more supercapacitors.

[0049] Specifically, based on the characteristics of the DC bus 4, the system can expand the power supply stability, such as: configuring an energy storage device 7 (supercapacitor, battery, etc.) to provide corresponding supporting energy for the DC bus 4 to avoid power swings, meet the system's anti-power swing requirements, and give full play to the flexible advantages of the DC system.

[0050] The control power supply of this system adopts a dual-path redundant mode of external UPS and main circuit transformer auxiliary power supply. All rectifier, inverter and DCDC modules can be maintained under power, which greatly improves the reliability of the system.

[0051] Example 2

[0052] like Figure 2 As shown, this embodiment provides a frequency conversion system for a cracking furnace fan motor sharing a DC bus 4, comprising: two sets of mutually redundant transformer and rectifier units, a plurality of inverter modules 5 and a DC bus 4;

[0053] Each group of transformer and rectifier units includes a transformer module 2 and a rectifier module 3. The input end of the transformer module 2 is connected to the AC bus 1, the output end of the transformer module 2 is connected to the input end of the rectifier module 3, and the output end of the rectifier module 3 is connected to the DC bus 4. The rectifier module 3 is used to convert AC power into DC power.

[0054] The input end of each inverter module 5 is connected to the DC bus 4, and the output end of each inverter module 5 is connected to the motor 6 of a cracking furnace fan. The inverter module 5 is used to convert the energy of the DC bus 4 into AC outputs of different voltages and frequencies, providing the required energy and speed regulation control for the operation of the motor 6.

[0055] In this embodiment, the transformer module 2 includes a transformer, and the rectifier module 3 includes an AFE controllable rectifier;

[0056] The input end of the transformer is connected to the AC bus 1 , and the output end of the transformer is connected to the input end of the AFE controlled rectifier.

[0057] Specifically, the system adopts dual power supply lines. The transformer uses two conventional high-voltage transformers running in parallel. After rectification by the AFE controlled rectifier, the grid-side harmonic content is less than 5%; the two rectifiers respectively adjust the AC voltage to DC voltage and jointly establish a DC bus 4. The AFE controlled rectifier includes three-phase fuses, IGBT power components, control switches, etc.

[0058] In this embodiment, a control switch 9 is further provided between the transformer module 2 and the inverter module 5 of the two sets of transformer and rectifier units, and the control switch 9 may be a contactor or a relay. Through the control switch 9, the two rectifiers connected to the two sections of the AC bus 1 can provide redundant power to the DC bus 4, and both can provide energy to the DC bus 4. Preferably, the AC bus 1 in this embodiment provides 10KV three-phase AC power, the rated capacity of the transformer is 2000KVA, and the rated voltage is 10 / 0.69KV. In other embodiments, the AC bus 1 may also be an AC bus of other high voltage levels, and transformers of other rated capacities and rated voltages may also be used as required.

[0059] In this embodiment, the inverter module 5 includes an inverter, an input end of the inverter is connected to the DC bus 4 , and an output end of the inverter is connected to an input end of the motor 6 .

[0060] Specifically, the inverter can convert the energy of the DC bus 4 into corresponding AC output according to the actual needs of the motor 6, and provide energy and speed regulation for the operation of the motor. This embodiment uses one inverter. In other embodiments, the inverter module 5 may also include two inverters, and the input ends of the two inverters are respectively connected to the DC bus 4, and the input ends of the two inverters are respectively connected to the input ends of the motor 6, and the two inverters are redundant.

[0061] In this embodiment, the system further includes a control unit, which is used to adjust the output frequency and voltage of the inverter according to the parameters set by the user and the feedback signal, so as to achieve precise control of the motor 6.

[0062] In this embodiment, an auxiliary power supply module is also included. The auxiliary power supply module is connected to the DC bus 4. The auxiliary power supply module is used to provide energy support for the DC bus 4 to meet the anti-power shaking requirement.

[0063] The auxiliary power module includes an energy storage device 7 and a DC / DC converter 8, and the energy storage device 7 is connected to the DC bus 4 through the DC / DC converter 8. The energy storage device 7 includes at least one supercapacitor and / or at least one battery pack. The energy storage device 7 in this embodiment adopts a supercapacitor.

[0064] Specifically, the power supply stability can be expanded based on the characteristics of the DC bus 4, such as configuring an energy storage device 7 (supercapacitor, battery, etc.) to provide corresponding supporting energy for the DC bus 4 to avoid power fluctuations.

[0065] The various embodiments of the utility model have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A cracking furnace fan motor common DC bus frequency conversion system, characterized in that: include: Two sets of mutually redundant transformer and rectifier units, multiple inverter modules and a DC bus; Each group of transformer and rectifier units includes a transformer module and a rectifier module, the input end of the transformer module is connected to the AC bus, the output end of the transformer module is connected to the input end of the rectifier module, the output end of the rectifier module is connected to the DC bus, and the rectifier module is used to rectify the AC power into DC power; The input end of each inverter module is connected to the DC bus, and the output end of each inverter module is connected to the motor of a cracking furnace fan. The inverter module is used to convert the energy of the DC bus into AC output of different voltages and frequencies to provide the required energy and speed regulation control for the operation of the motor.

2. The cracking furnace fan motor common DC bus frequency conversion system according to claim 1 is characterized in that: The transformer module includes a 24-pulse rectifier transformer, and the rectifier module includes a rectifier; The input end of the 24-pulse rectifier transformer is connected to the AC bus, and the output end of the 24-pulse rectifier transformer is divided into four paths connected to the input end of the rectifier.

3. The cracking furnace fan motor common DC bus frequency conversion system according to claim 1 is characterized in that: The voltage transformation module includes a transformer, and the rectifier module includes an AFE controllable rectifier; The input end of the transformer is connected to the AC bus, and the output end of the transformer is connected to the input end of the AFE controlled rectifier.

4. The cracking furnace fan motor common DC bus frequency conversion system according to claim 2 or 3, characterized in that: The inverter module includes an inverter, an input end of the inverter is connected to the DC bus, and an output end of the inverter is connected to an input end of the motor.

5. The cracking furnace fan motor common DC bus frequency conversion system according to claim 2 or 3, characterized in that: The inverter module includes two inverters, the input ends of the two inverters are respectively connected to the DC bus, the input ends of the two inverters are respectively connected to the input ends of the motor, and the two inverters are redundant to each other.

6. The cracking furnace fan motor common DC bus frequency conversion system according to claim 1, characterized in that: It also includes an auxiliary power supply module, which is connected to the DC bus and is used to provide energy support for the DC bus to meet the anti-power shaking requirement.

7. The cracking furnace fan motor common DC bus frequency conversion system according to claim 6, characterized in that: The auxiliary power supply module includes an energy storage device and a DC / DC converter, and the energy storage device is connected to the DC bus through the DC / DC converter.

8. The cracking furnace fan motor common DC bus frequency conversion system according to claim 7, characterized in that: The energy storage device includes at least one supercapacitor and / or at least one battery group.

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