A dual frequency converter speed control system for dry coke quenching hoist

Abstract

The utility model discloses a dual-frequency converter speed regulation system for a dry coke quenching hoist, comprising a power distribution unit, a dual-frequency conversion component, a dual power conversion unit, a hoist motor and a PLC; the power output end of the power distribution unit is respectively connected to the input ends of two frequency conversion units, the output ends of the two frequency conversion units are respectively connected to the two input ends of the dual-power conversion unit, and the two output ends of the dual-power conversion unit are both connected to the three-phase wiring terminals of the hoist motor; the PLC is electrically connected to the power distribution unit, the dual-frequency conversion component and the dual-power conversion unit through a digital quantity input and output module; the utility model solves the single weak disadvantage of single-frequency converter control in the current hoist industry, and the two frequency converters serve as backup for each other, thereby improving the reliability of stable and safe operation of the hoist.

Description

Technical Field

[0001] The utility model relates to the technical field of variable frequency speed regulation of hoists, in particular to a double frequency converter speed regulation system of a dry coke quenching hoist. Background Art

[0002] As the country attaches great importance to environmental protection, the quenching method of coke in coking enterprises has become more stringent. The coke in coking plants has gradually changed from the wet quenching method that pollutes the atmospheric environment to the safe and environmentally friendly dry quenching method. The safe and stable operation of the dry quenching elevator is a key link in the coking production process and a key control factor. If the elevator inverter fails, the dry quenching will not be able to produce normally, and even cause the furnace to stop production.

[0003] At present, the dry quenching coke elevators in coking plants across the country are all controlled by a single frequency converter. When a fault occurs, it is repaired by replacing spare parts. Major faults require the purchase of a new frequency converter for replacement. If a single frequency converter fails, the elevator cannot operate normally, seriously affecting production. Utility Model Content

[0004] The utility model provides a dual-frequency converter speed regulation system for a dry coke quenching hoist, which can at least solve one problem pointed out in the background technology.

[0005] A dual frequency converter speed control system for a dry coke quenching hoist, comprising a power distribution unit, a dual frequency conversion component, a dual power conversion unit, a hoist motor and a PLC;

[0006] The dual frequency conversion assembly includes two frequency conversion units;

[0007] The power output end of the power distribution unit is respectively connected to the input ends of the two frequency conversion units, the output ends of the two frequency conversion units are respectively connected to the two input ends of the dual power conversion unit, and the two output ends of the dual power conversion unit are both connected to the three-phase terminal of the hoist motor;

[0008] The PLC is electrically connected to the power distribution unit, the dual frequency conversion component, and the dual power conversion unit through a digital quantity input and output module.

[0009] Preferably, the output end of the encoder of the hoist motor is connected to the input end of the signal distributor, and the two output ends of the signal distributor are respectively connected to the encoder modules of the two frequency conversion units.

[0010] Preferably, one of the frequency conversion units is a split structure, and its power is greater than the motor power. The frequency conversion unit includes a rectifier and filter module and an inverter module. The input end of the rectifier and filter module is connected to the output end of the distribution unit, the output end of the rectifier and filter module is connected to the input end of the inverter module, and the output end of the inverter module is connected to the input end of the dual power conversion unit.

[0011] Preferably, the dual power conversion unit is a dual power knife switch, and the auxiliary contacts and the switching confirmation knob contacts of the dual power knife switch are connected in series and connected to the PLC.

[0012] Preferably, the power distribution unit is a frame-type 1600A circuit breaker, and its Ics operating short-circuit segment current is not less than 54.26KA.

[0013] Compared with the prior art, the beneficial effects of the utility model are as follows: the utility model solves the single weakness of single inverter control in the current elevator industry, and the two inverters serve as backup for each other, which improves the reliability of stable and safe operation of the elevator. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the electrical primary main schematic diagram of the utility model;

[0015] Figure 2 This is the control principle diagram of the rectifier and filter module of the utility model;

[0016] Figure 3 This is the control principle diagram of the inverter module of the utility model;

[0017] Figure 4 This is the encoder speed control principle of the utility model;

[0018] Figure 5 This is the I / O control diagram of the PLC of the utility model.

[0019] Description of reference numerals:

[0020] 1-power distribution unit, 2-frequency conversion unit, 21-rectifier filter module, 22-inverter module, 3-dual power conversion unit, 4-hoist motor, 5-digital input and output module, 6-signal distributor. DETAILED DESCRIPTION

[0021] A specific implementation of the present utility model is described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present utility model is not limited by the specific implementation mode.

[0022] like Figures 1 to 5 As shown, a dual frequency converter speed control system for a dry coke quenching hoist provided by the embodiment of the utility model comprises a power distribution unit 1, a dual frequency conversion component, a dual power conversion unit 3, a hoist motor 4 and a PLC;

[0023] The dual frequency conversion assembly includes two frequency conversion units 2;

[0024] The power output end of the power distribution unit is respectively connected to the input ends of the two frequency conversion units, the output ends of the two frequency conversion units are respectively connected to the two input ends of the dual power conversion unit, and the two output ends of the dual power conversion unit are both connected to the three-phase wiring terminals of the hoist motor;

[0025] The PLC is electrically connected to the power distribution unit, the dual frequency conversion component, and the dual power conversion unit through the digital input and output module 5.

[0026] The power distribution unit is a frame-type 1600A circuit breaker, and its Ics operating short-circuit segment current is not less than 54.26KA.

[0027] Specifically, the lifting motor of this embodiment is a 380V / 450KW three-phase AC asynchronous motor, and the motor is equipped with an HTL encoder;

[0028] Power distribution unit: equipped with main power circuit breaker, inverter (frequency conversion unit) pre-charging, providing rectifier inverter module, filter module power supply and 24V secondary control power supply and frequency conversion control part relay;

[0029] Dual frequency conversion assembly: includes two frequency conversion units, namely the existing frequency converter and the newly installed frequency converter. The technical solution of this embodiment is an improvement on the existing single frequency conversion speed regulation system. It is mainly to solve the problem that after the frequency converter of the existing single frequency conversion speed regulation system fails, it is necessary to wait for the replacement of a new frequency converter or maintenance, which affects the normal production of dry coke quenching. Therefore, another frequency converter is added on its basis. When the hoist is operating, the hoist can move up and down within the lifting height range; the lifting speed changes according to the set operating curve, and adopts closed-loop frequency conversion control. The speed change of key points is controlled by inductive limit switches, cam limit switches, etc., and various interlocking signals are provided; here, it is required that the new frequency converter must be fully redundant with the old frequency converter;

[0030] The inverter in this embodiment uses ABB-ACS880 inverter, which is a split structure. The inverter has its own energy feedback function, and there is no need to add a power unit and a brake resistor. The power of the inverter is greater than the power of the hoist motor, 560KW. Figure 1 As shown, it is equipped with a rectification and filtering module 21 (such as Figure 2 As shown) and the inverter module 22 (as Figure 3 As shown); the input end of the rectifier and filter module is connected to the output end of the power distribution unit, the output end of the rectifier and filter module is connected to the input end of the inverter module, and the output end of the inverter module is connected to the input end of the dual power conversion unit;

[0031] The hoist motor is controlled by the frequency converter with multiple speeds, and performs data interlocking logic operation with the Siemens S7-400 PLC, integrating the new hoisting system into the old system, realizing automatic control, fault interlocking, reducing work intensity, and reducing accidents;

[0032] Dual power conversion unit: To achieve the switching of the above two inverters (inverter units), i.e., the main and standby inverters, the dual power switching unit adopts a dual power knife switch, which is installed in the cabinet. The auxiliary contacts of the dual power knife switch and the switching confirmation knob contacts of the lifting drive device are connected in series and then connected to the PLC system. After the PLC logic judgment, the main mechanism is allowed to close the main switch, and the closing action of the main switch is realized by the operation start signal;

[0033] Encoder speed feedback signal:

[0034] The ACS880 inverter used has added a closed-loop control link of speed feedback on the basis of vector control for more stable and reliable braking. After the encoder (original encoder) of the hoist motor is connected to a one-input and two-output device (signal distributor), one path is connected back to the encoder module of VFD1 (1# inverter), and the other path is connected to the encoder module of VFD2 (2# inverter). The ABB acquisition module selection: FEN-31, HTL encoder module; the output end of the encoder of the hoist motor is connected to the input end of the signal distributor, and the two output ends of the signal distributor are respectively connected to the encoder modules of the two inverters;

[0035] PLC input and output control and feedback signals:

[0036] The backup hoisting control system (ACS880 inverter) provides the following output signals to the PLC control system:

[0037] Emergency stop button signal, standby lifting signal input, common lifting signal input, standby system ready, rectifier device failure, inverter device failure, lifting inverter opening signal;

[0038] The following signals are required from PLC:

[0039] Backup system start / stop (relay K003), main circuit breaker opening (emergency stop) (relay K016), rectifier reset (relay K028), rise (relay K004), fall (relay K005), speed 1 (relay K006), speed 2 (relay K007), speed 3 (relay K008), inverter reset (relay K009), inverter frequency, current feedback.

[0040] Emergency stop circuit:

[0041] The emergency stop buttons are distributed in the control room, 1# and 2# inverters, electrical room, beside the hoist and in the operation room. The PLC sends out a new emergency stop signal. During the emergency stop, the pulse blocks the standby hoisting inverter and is connected in series with the original emergency stop circuit.

[0042] Brake control:

[0043] The system motor brake control adopts the unique "vector control type" and "brake control" functions of ABB inverter. The inverter detects the motor output torque in real time, and the threshold for opening the brake can be set through the "brake opening torque" parameter; when the output torque reaches the torque required for lifting, the brake will automatically open. When the inverter fails, or the enable signal is lost, or the speed is lower than a certain set threshold, the brake will automatically close to ensure reliable operation of the equipment; Figure 1 Before the Y9 brake motor is opened, the internal logic of the brake output interface K203 relay will first perform torque verification and slip verification. After passing, the K203 relay will operate and the Y9 brake motor will open.

[0044] In order to solve the problem that the elevator cannot operate normally due to a single inverter failure and seriously affects production, a spare inverter is added on the basis of the existing control method, and the PLC logic operation function, automatic control technology and variable frequency speed regulation technology are used to achieve rapid switching of the dual inverters. Therefore, the dual inverter speed regulation system technology of the dry quenching elevator of this embodiment fills the technical gap in the elevator industry.

[0045] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and basic features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim involved.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A dual frequency converter speed control system for a dry coke quenching hoist, characterized in that: It includes power distribution unit, dual frequency conversion components, dual power conversion unit, hoist motor and PLC; The dual frequency conversion assembly includes two frequency conversion units; The power output end of the power distribution unit is respectively connected to the input ends of the two frequency conversion units, the output ends of the two frequency conversion units are respectively connected to the two input ends of the dual power conversion unit, and the two output ends of the dual power conversion unit are both connected to the three-phase terminal of the hoist motor; The PLC is electrically connected to the power distribution unit, the dual frequency conversion component, and the dual power conversion unit through a digital input and output module.

2. The dual-frequency converter speed control system of the dry coke quenching hoist according to claim 1, characterized in that: The output end of the encoder of the hoist motor is connected to the input end of the signal distributor, and the two output ends of the signal distributor are respectively connected to the encoder modules of the two frequency conversion units.

3. The dual-inverter speed control system for the dry quenching coke hoist according to claim 1, characterized in that: One of the frequency conversion units is a split structure, and its power is greater than the motor power. The frequency conversion unit includes a rectifier and filter module and an inverter module. The input end of the rectifier and filter module is connected to the output end of the distribution unit, the output end of the rectifier and filter module is connected to the input end of the inverter module, and the output end of the inverter module is connected to the input end of the dual power conversion unit.

4. The dual-frequency converter speed control system for the dry quenching coke hoist according to claim 1, characterized in that: The dual power conversion unit is a dual power knife switch, the auxiliary contacts and the switching confirmation knob contacts of the dual power knife switch are connected in series and connected to the PLC.

5. The dual-frequency converter speed control system for the dry quenching coke hoist according to claim 1, characterized in that: The power distribution unit is a frame-type 1600A circuit breaker, and its Ics operating short-circuit segment current is not less than 54.26KA.

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