Emergency power supply device and transmission device for rotary furnace body

Abstract

This invention provides an emergency power supply device and transmission device for a rotary kiln body, including a DC system, a control device, and at least two AC frequency converters. The AC frequency converters are connected to the municipal power grid via AC input lines, and an input isolating switch is installed at the input end of the AC input lines. An input contactor is installed on the AC input lines. The AC output of each AC frequency converter is connected to the drive motor of the rotary kiln body via an AC output line. A DC contactor is installed at the DC port of each AC frequency converter. The DC system includes a DC power supply panel and a power storage device. The charging module includes an input end and an output end; the input end is connected to the municipal power grid; the output end is connected to the power storage device and a common DC bus. The common DC bus is connected to the DC contactors of each AC frequency converter. The control device includes a PLC control system. This invention solves the current problems of lacking a reliable, simplified, and highly integrated emergency power supply solution for rotary kiln bodies.

Description

Technical Field

[0001] This invention relates to the field of metallurgical power technology, and more specifically, to an emergency power supply device and transmission device for a rotary kiln body. Background Technology

[0002] Rotary furnaces, commonly used in the non-ferrous metallurgical industry (such as bottom-blown furnaces, converters, anode furnaces, and Kaldor furnaces), are characterized by their ability to rotate as needed according to smelting process requirements and to quickly return to a safe position in the event of a power outage. The transmission configuration of their main drive motor and the reliability and rationality of their emergency power supply system directly affect the safety and stability of metallurgical production.

[0003] Currently, to improve power supply reliability, the mechanical transmission configuration of rotary kilns is basically an AC wound-rotor or squirrel-cage motor + DC motor. The AC motor is responsible for normal production operation, and the DC motor is responsible for emergency handling after a power outage. With the emergence and maturity of EPS (Electric Power Supply), the reliability of AC power supply can now meet the requirements of process production. The mechanical transmission configuration of the rotary kiln has been changed to a single AC squirrel-cage motor, greatly simplifying the mechanical parts. Its electrical transmission and emergency power supply configurations are basically implemented in two schemes: 1 EPS (non-frequency adjustable) + 2 frequency converters + 1 AC squirrel-cage motor or 1 EPS (frequency adjustable) + 1 AC squirrel-cage motor. Among them, the EPS (frequency adjustable) + AC squirrel-cage motor scheme is less reliable than configuring two frequency converters alone because the EPS can only be equipped with 1 frequency adjustable inverter. Although this mode has a relatively simple structure, its reliability is lacking, so it is not widely used in practice. Another type of AC emergency power supply is a diesel generator, but its power supply response time is generally more than 10 seconds, which cannot meet the timely requirements for rotating the kiln in case of an accident. EPS lacks corresponding production and testing standards abroad and has not yet received international certification. Therefore, using EPS as an emergency power source for rotary kilns is inappropriate.

[0004] Abroad, the only AC emergency power supply equipment available is UPS and diesel generators. UPS is generally only used as an emergency power source for loads with small impacts and fluctuations, and it is not suitable for such high-load power equipment. Diesel generators, on the other hand, cannot meet the time response requirements.

[0005] In summary, there is currently a lack of a reliable, simple, and highly integrated emergency power supply solution for rotary kilns. Summary of the Invention

[0006] In view of the above problems, the purpose of this invention is to provide an emergency power supply device and transmission device for rotary kiln bodies, so as to solve the problem that there is currently a lack of a reliable, simple and highly integrated emergency power supply solution for rotary kiln bodies.

[0007] This invention provides an emergency power supply device for a rotary kiln body, comprising a DC system, a control device, and at least two AC frequency converters; wherein,

[0008] Each of the AC frequency converters is connected to the municipal power grid via an AC input line, and an input line isolating switch is installed at the power input end of the AC input line; an input line contactor is installed on the AC input line; the AC output of each of the AC frequency converters is connected to the drive motor of the rotary kiln body via an AC output line; a DC contactor is installed at the DC port of the AC frequency converter; and an output line contactor is installed on the AC output line.

[0009] The DC system includes a DC power supply and an energy storage device; the DC power supply includes a charging module and an output circuit connected to the charging module; the charging module includes an input terminal and an output terminal, and an automatic transfer switch is provided at the input terminal; the automatic transfer switch is connected to the mains power grid; an energy storage device and a common DC bus are connected at the output terminal; the common DC bus is connected to the DC contactor of each of the AC frequency converters.

[0010] The control device includes a PLC control system, an information acquisition module connected to the PLC control system, and a communication port; the information acquisition module is connected to each of the AC frequency converters, the AC input line of each AC frequency converter, the input contactor, the DC contactor, and the output contactor; the communication port is connected to the charging module.

[0011] Furthermore, a preferred embodiment is that the number of AC frequency converters is two.

[0012] Furthermore, a preferred embodiment is to provide an inverter input line protection device at the AC input of the AC inverter; the inverter input line protection device includes a fast fuse and an input line reactor.

[0013] Furthermore, a preferred embodiment is to provide a frequency converter output harmonic suppression device at the AC output of the AC frequency converter; the frequency converter output harmonic suppression device includes an output reactor.

[0014] Furthermore, a preferred embodiment is to install a unidirectional diode on the common DC bus.

[0015] In addition, a preferred embodiment is to provide a common braking module and braking resistor on the common DC bus.

[0016] Furthermore, a preferred embodiment is to provide a pre-charge circuit on the DC side of the AC inverter.

[0017] Furthermore, a preferred embodiment is that the energy storage device is a lead-acid battery pack.

[0018] Furthermore, a preferred embodiment is that an inverter is connected to the charging module.

[0019] The present invention provides a transmission device for a rotary kiln body, including a transmission motor for the rotary kiln body and an emergency power supply device as described above connected to the transmission motor.

[0020] As can be seen from the above technical solution, the emergency power supply device and transmission device for the rotary kiln body provided by the present invention are formed by reasonably arranging and connecting at least two AC frequency converters, a DC system, and a control device. Each individual hardware component is independent and consists of mature products available on the market. Each unit can obtain certification independently. The entire system is integrated through the functional interfaces of the internal units, which can solve the problem of EPS certification not being available in overseas projects. The emergency power supply device and the kiln body rotation control provided by the present invention are integrated into one, reducing intermediate links and saving investment. Through the structural design of the AC frequency converter and the connection of at least two AC frequency converters together using a common DC bus, and then connecting to the output terminal of the charging module through DC contactors set at their respective DC ports, power can be supplied to the drive motor of the rotary kiln body while simultaneously supplying power to the energy storage device. The design of the control device allows the emergency power control and the kiln body rotation control to be integrated into one, which is responsible for monitoring, switching, and controlling the power supply, as well as controlling the transmission of the kiln body and external interlocks, making the integration of the entire device higher. The DC power supply is always online, and the emergency power supply can be put into operation almost immediately upon power failure.

[0021] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0022] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings:

[0023] Figure 1 This is a schematic diagram of the emergency power supply device for the rotary kiln body according to an embodiment of the present invention.

[0024] In the attached diagram, 1-AC frequency converter, 11-incoming disconnect switch, 12-incoming contactor, 13-DC contactor, 14-fast fuse, 15-incoming reactor, 16-outgoing reactor, 17-outgoing contactor, 2-mains power grid, 3-DC system, 31-DC power supply, 311-charging module, 3111-input terminal, 3112-output terminal, 312-automatic transfer switch, 313-inverter, 32-energy storage device, 4-control device, 41-PLC control system, 42-information acquisition module, 43-communication port, 5-drive motor, 6-common DC bus, 71-braking module, 72-braking resistor, 8-diode.

[0025] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0026] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details.

[0027] Example: In a foreign project, the main motor of the bottom-blown furnace has a rated power of 280kW and a rated voltage of AC 460V. It is a squirrel-cage motor and requires frequency conversion speed regulation. The emergency working time is considered to be 10 minutes.

[0028] In response to the aforementioned issues regarding the lack of a reliable, simple, and highly integrated emergency power supply solution for rotary kilns, an emergency power supply device and transmission device for rotary kilns are proposed.

[0029] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] To illustrate the emergency power supply device for the rotary kiln body provided by the present invention, Figure 1 The structure of an emergency power supply device for a rotary kiln body according to an embodiment of the present invention is shown.

[0031] like Figure 1 As shown, the emergency power supply device for the rotary kiln body provided by the present invention includes a DC system 3, a control device 4, and at least two AC frequency converters 1; wherein,

[0032] Each AC frequency converter 1 is connected to the municipal power grid 2 via an AC input line. An input line isolating switch 11 is installed at the power input end of the AC input line. An input line contactor 12 is installed on the AC input line. The AC output of each AC frequency converter 1 is connected to the drive motor 5 of the rotary kiln body via an AC output line. A DC contactor 13 is installed at the DC port of the AC frequency converter 1. An output line contactor 17 is installed on the AC output line.

[0033] The DC system 3 includes a DC power supply 31 and an energy storage device 32; the DC power supply 31 includes a charging module 311 and an output circuit connected to the charging module 311; the charging module 311 includes an input terminal 3111 and an output terminal 3112, and an automatic transfer switch 312 is provided at the input terminal 3111; the automatic transfer switch 312 is connected to the mains power grid 2; a common DC bus 6 is connected to the output terminal 3112; the common DC bus 6 is connected to the DC contactor 13 of each AC frequency converter 1.

[0034] The control device 4 includes a PLC control system 41, an information acquisition module 42 and a communication port 43 respectively connected to the PLC control system 41; the information acquisition module 42 is connected to each AC inverter 1, the AC input line of each AC inverter 1, the input contactor 12, the DC contactor 13 and the output contactor 17 respectively; the communication port 43 is connected to the charging module 311.

[0035] The AC power supply for each AC frequency converter 1 is drawn from the upstream substation (municipal power grid), and each power supply is independent of the others, thereby increasing the reliability of power supply.

[0036] Considering that the load is the drive motor 5 that rotates the furnace body, which operates intermittently for short periods and is prone to overload during rotation, each AC frequency converter 1 is selected according to the rated power of the main motor of the furnace body for heavy load.

[0037] At least two AC frequency converters 1 have their DC ports connected to a common DC bus 6 via DC contactors 13, and are connected to the DC panel 31 of the DC system 3. This design features high centralization and a streamlined structure.

[0038] The DC power supply panel 31 of the DC system 3 is responsible for charging the lead-acid battery pack and providing DC power output, while also monitoring and protecting the status of various DC components and the battery pack. The DC power supply panel 31 has dual AC power inputs and an internal ATS (Automatic Power Supply System) for power switching.

[0039] The PLC control system 41 includes a digital-to-analog module, which is connected to the information acquisition module 42. The information acquisition module 42 is responsible for acquiring the current and voltage signals of each component, converting them into 4-20mA signals, and sending them to the PLC control system. The communication port 43 acquires the charging information of the DC system 3 and sends the charging information to the PLC control system. The PLC control system is responsible for monitoring the operating status of the entire transmission system and the DC system, and participating in the furnace rotation control.

[0040] This system is constructed by rationally arranging and connecting at least two AC frequency converters 1, a DC system 3, and a control device 4. Each individual hardware component is independent and consists of mature products available on the market. Each unit can be certified independently, and the entire system is integrated through the functional interfaces of each internal unit, which can solve the problem of EPS certification failure in overseas projects. The emergency power supply device and furnace rotation control provided by this invention are integrated into one, reducing intermediate links and saving investment. Through the structural design of the AC frequency converter 1 and the connection of at least two AC frequency converters 1 together via a common DC bus 6, and then connecting to the output terminal 3112 of the charging module 311 through DC contactors 13 set at their respective DC ports, it can supply power to the drive motor 5 of the rotary furnace body and the energy storage device 32 at the same time. The design of the control device 4 can integrate the emergency power supply control and the furnace rotation control into one, which is responsible for monitoring, switching, and controlling the power supply, as well as the drive control of the furnace body and external interlocks, making the integration of the entire device higher. The DC power supply is always online, and the emergency power supply can be put into operation almost immediately after a power outage.

[0041] As a preferred embodiment of the present invention, the number of AC frequency converters 1 is two (e.g., ...). Figure 1 (As shown).

[0042] The emergency power supply device for the rotary kiln body provided in this embodiment of the invention uses two AC frequency converters 1, one for operation and one for backup. If one fails, the backup unit can still operate without affecting the normal operation of the equipment. The two AC frequency converters 1 adopt a common DC bus technology, which can be used in situations where one AC frequency converter drives multiple inverters. One rectifier unit drives many inverters through the shared common DC bus technology, which are connected to different motors, thus expanding the application scenarios. At the same time, it facilitates the connection of the energy storage device 32 and the braking module 71 in the subsequent DC system 3.

[0043] As a preferred embodiment of the present invention, an inverter input line protection device is provided at the AC input of the AC inverter 1; the inverter input line protection device includes a fast fuse 14 and an input line reactor 15. By setting the main components such as the fast fuse 14 and the input line reactor 15 and their specifications and capacities, the AC input terminal of the AC inverter 1 can be protected.

[0044] As a preferred embodiment of the present invention, a frequency converter output harmonic suppression device is provided at the AC output of the AC frequency converter 1; the frequency converter output harmonic suppression device includes an output reactor 16. By setting the main components such as the output reactor and their specifications and capacities, the AC output terminal of the AC frequency converter can be protected.

[0045] As a preferred embodiment of the present invention, a unidirectional diode 8 is provided on the common DC bus 6 to prevent damage to the DC system 3 in the event of overvoltage on the DC side of the AC inverter 1.

[0046] In a preferred embodiment of the present invention, a common braking module 71 and braking resistor 72 are provided on the common DC bus 6. To prevent overvoltage during operation in the fourth quadrant, a braking module 71 and braking resistor 72 are configured on the common DC bus 7. The operating voltage of the braking module 71 is set higher than the voltage of the DC system 3, but lower than the safety voltage of the AC frequency converter.

[0047] As a preferred embodiment of the present invention, a pre-charge circuit is provided on the DC side of the AC inverter 1. This pre-charge circuit is provided on the DC side inside the AC inverter 1 to protect it.

[0048] In a preferred embodiment of the present invention, the energy storage device 32 is a lead-acid battery pack; the lead-acid battery pack includes at least 310 individual 2V, 500Ah batteries connected in series. The float charge voltage of the lead-acid battery pack is selected based on the rated voltage of the main motor of the furnace body, generally 1.35 times the rated voltage of the main motor, which is 620V. The capacity of the lead-acid battery pack is determined comprehensively based on the starting current of the main motor of the furnace body, the emergency working time, and the discharge curve of the battery pack, and 500Ah is selected. The lead-acid battery pack includes at least 310 individual 2V, 500Ah batteries connected in series. Individual batteries are selected as 2V, 500Ah, and the battery pack has at least 310 individual batteries connected in series.

[0049] In a preferred embodiment of the present invention, an inverter 313 is connected to the charging module 311. The addition of an inverter 313 within the DC power supply panel 31 provides reliable AC and DC power to the control system.

[0050] The transmission device for the rotary kiln body provided by the present invention includes a transmission motor 5 for the rotary kiln body and an emergency power supply device as described above connected to the transmission motor 5.

[0051] As can be seen from the above specific embodiments, the emergency power supply device and transmission device for the rotary kiln body provided by the present invention are composed of at least two AC frequency converters, a DC system, and a control device arranged and connected in a reasonable manner. Each individual hardware component is independent and consists of mature products available on the market. Each unit can obtain certification independently. The entire system is integrated through the functional interfaces of each internal unit, which can solve the problem of EPS certification not being available in overseas projects. The emergency power supply device and the kiln body rotation control provided by the present invention are integrated into one, reducing intermediate links and saving investment. Through the structural design of the AC frequency converter and the connection of at least two AC frequency converters together using a common DC bus, and then through DC contactors set at their respective DC ports to connect to the charging module, power can be supplied to the drive motor of the rotary kiln body while simultaneously supplying power to the energy storage device. The design of the control device allows the emergency power control and the kiln body rotation control to be integrated into one, which is responsible for monitoring, switching, and controlling the power supply, as well as controlling the transmission of the kiln body and external interlocks, making the integration of the entire device higher. The DC power supply is always online, and the emergency power supply can be put into operation almost immediately upon power failure.

[0052] The emergency power supply device and transmission device for the rotary kiln body according to the present invention have been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the emergency power supply device and transmission device for the rotary kiln body proposed in the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. An emergency power supply device for a rotary kiln body, characterized in that, Includes a DC system, control unit, and at least two AC frequency converters; among which, Each of the AC frequency converters is connected to the municipal power grid via an AC input line, and an input line isolating switch is installed at the power input end of the AC input line; an input line contactor is installed on the AC input line; the AC output of each of the AC frequency converters is connected to the drive motor of the rotary kiln body via an AC output line; a DC contactor is installed at the DC port of the AC frequency converter; an output contactor is installed on the AC output line; and a pre-charge circuit is installed on the DC side of the AC frequency converter. The DC system includes a DC power supply and an energy storage device; the DC power supply includes a charging module and an output circuit connected to the charging module; the charging module includes an input terminal and an output terminal, and an automatic transfer switch is provided at the input terminal; the automatic transfer switch is connected to the municipal power grid; an energy storage device and a common DC bus are connected at the output terminal; the common DC bus is connected to the DC contactors of each of the AC frequency converters; a common braking module and braking resistor are provided on the common DC bus. The control device includes a PLC control system, an information acquisition module connected to the PLC control system, and a communication port. The information acquisition module is connected to each of the AC frequency converters, the AC input line of each AC frequency converter, the input contactor, the DC contactor, and the output contactor. The communication port is connected to the charging module. The PLC control system includes a digital-to-analog module connected to the information acquisition module. The information acquisition module converts current and voltage signals into 4-20mA signals and sends them to the PLC control system.

2. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, The number of AC frequency converters is two.

3. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, A frequency converter input line protection device is installed at the AC input of the AC frequency converter; the frequency converter input line protection device includes a fast fuse and an input line reactor.

4. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, A frequency converter output harmonic suppression device is provided at the AC output of the AC frequency converter; the frequency converter output harmonic suppression device includes an output reactor.

5. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, A unidirectional diode is installed on the common DC bus.

6. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, The energy storage device is a lead-acid battery pack.

7. The emergency power supply device for the rotary kiln body according to claim 1, characterized in that, An inverter is connected to the charging module.

8. A transmission device for a rotary kiln body, characterized in that, The device includes a drive motor for the rotary kiln body and an emergency power supply device as described in any one of claims 1-7 connected to the drive motor.

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