Intelligent power supply combination switch of complete set equipment for fast excavation in underground coal mine and operation method thereof

Abstract

This invention belongs to the field of underground power supply technology in coal mines, and discloses an intelligent power supply combination switch and its operation method for a complete set of rapid excavation equipment in coal mines. It includes: an intelligent voltage regulator, multiple dynamic reactive power compensation devices, first and second switching switches, and multiple third switching switches. The intelligent voltage regulator includes a rectifier stage, an intermediate stage, and multiple inverter stages connected in parallel. The input terminal of the rectifier stage is connected to the output terminal of a mobile transformer, and its output terminal is connected to the input terminals of each inverter stage via the intermediate stage. The output terminal of each inverter stage is connected to a rapid excavation load device. Each rapid excavation load device has a dynamic reactive power compensation device installed at its input terminal. The output terminal of the mobile transformer is connected to one end of the second and third switching switches via the first switching switch. The other end of each third switching switch is connected to a rapid excavation load device, and the other end of the second switching switch is connected to other loads. This invention improves the adaptability of the rapid excavation equipment to the on-site power grid.

Description

Technical Field

[0001] This invention belongs to the field of underground power supply technology in coal mines, specifically relating to an intelligent power supply combination switch and its operation method for a complete set of rapid excavation equipment in underground coal mines, used to control the operation of reactive power compensation and harmonic control in multi-motor equipment. Background Technology

[0002] With the increasing demand for coal energy, the power and speed requirements for underground tunneling equipment in coal mines are also gradually increasing. Rapid tunneling equipment integrates all aspects of the tunneling process, greatly improving tunneling efficiency; however, its power supply system has not undergone significant improvements. Limited by the current configuration of the underground power grid at the tunneling face, when a single tunneling distance exceeds 1 kilometer, it is generally necessary to move the mobile transformer supplying power to the rear, re-excavate the tunnel, and perform temporary support and connection / retraction of power cables. These processes result in significant delays and reduced tunneling efficiency. This is because as the tunneling distance increases, active power losses and reactive power exchange on the power supply lines cause voltage drops at the line end, i.e., on the equipment side, preventing the equipment from starting normally.

[0003] To improve the efficiency of tunneling operations and reduce the number of relocations, it is necessary to improve the power supply switches of the tunneling equipment to enhance the efficiency of rapid tunneling. Summary of the Invention

[0004] This invention overcomes the shortcomings of existing technologies and aims to solve the following technical problem: providing an intelligent power supply combination switch and its operation method for a complete set of rapid excavation equipment in coal mines. On the one hand, it improves the starting capability of each component, and on the other hand, it can compensate for the voltage drop and harmonic effects caused by active power loss in the line. It avoids the problems of protection malfunction and transformer capacity saturation caused by large reactive power loss and high harmonic ratio in AC power supply lines. With a relatively low cost, it greatly reduces the number of transformer relocations, thereby improving the efficiency of rapid excavation.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an intelligent power supply combination switch for a complete set of rapid excavation equipment in coal mines, comprising: an intelligent voltage regulator, multiple dynamic reactive power compensation devices, a first switching switch, a second switching switch, and multiple third switching switches. The intelligent voltage regulator includes a rectifier stage, an intermediate stage, and multiple inverter stages connected in parallel. The input terminal of the rectifier stage is connected to the output terminal of a mobile transformer, and the output terminal is connected to the input terminal of each inverter stage via the intermediate stage. The output terminal of each inverter stage is connected to a rapid excavation load device. Each rapid excavation load device is provided with a dynamic reactive power compensation device at its input terminal, and the dynamic reactive power compensation device is used to dynamically compensate the reactive power of the corresponding rapid excavation load device.

[0006] The output terminal of the mobile transformer is connected to one end of the first switching switch, the other end of the first switching switch is connected to one end of the second switching switch and each of the third switching switches, the other end of each of the third switching switches is connected to a fast excavation load device, and the other end of the second switching switch is connected to other loads;

[0007] The dynamic reactive power compensation device includes a T-type three-level topology and a third-order filter. The third-order filter is a reactance-capacitance-reactance structure. The T-type three-level topology is connected to the input terminal of the corresponding fast-digging load device through the third-order filter.

[0008] The rectifier stage adopts a diode-clamped three-level topology; the intermediate stage adopts a diode-clamped three-level dual active H-bridge topology, wherein the high-frequency transformer used has a turns ratio of 2:3; and the inverter stage adopts a diode-clamped three-level topology.

[0009] The input terminal of the rectifier stage is equipped with a first-order filter formed by reactance, and the output terminal of the inverter stage is equipped with a second-order filter composed of reactance and capacitance.

[0010] The rectifier stage adopts PWM rectification control, the intermediate stage adopts phase shift control, and each inverter stage performs real-time compensation based on the voltage of the currently connected load.

[0011] There are four inverter stages, and the output of each inverter stage is connected to the inlet of the roadheader, the bolt transfer machine, the belt transfer machine, and the self-propelled tail section machine, respectively.

[0012] Furthermore, this invention also provides an operating method for an intelligent power supply combination switch of a complete set of rapid underground excavation equipment in a coal mine, comprising the following steps:

[0013] (1) After receiving the power-on command, first determine whether the first switch, the second switch and the third switch are in the off state. After confirming that they are all in the off state, start the rectifier stage of the intelligent voltage regulator.

[0014] (2) After startup, determine the first-stage DC bus voltage V at the rectifier stage output. P1N1 If it is within the first normal range, then start the intermediate level and proceed to step (3); otherwise, proceed to step (4).

[0015] (3) Determine the DC bus voltage V at the output terminal of the intermediate stage. P2N2 If it is within the second normal range, start the inverter stage corresponding to each fast excavation load device one by one. After each inverter stage is successfully started, start the dynamic reactive power compensation device corresponding to that inverter stage. After all inverter stages and corresponding dynamic reactive power compensation devices are started, start the second switching switch. After all are started, start each device of the fast excavation complete set of equipment. If not, proceed to step (4).

[0016] (4) Close the first switching switch, the second switching switch and each of the third switching switches to start each device of the rapid excavation equipment.

[0017] The first normal range is related to the AC bus voltage on the input side of the rectifier stage.

[0018] The second normal range is related to the output voltage of each inverter stage.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. This invention provides an intelligent power supply combination switch and its operation method for a complete set of rapid tunneling equipment in coal mines. By connecting dynamic reactive power compensation devices in parallel on each equipment side of the tunneling equipment and adding a series voltage regulating device on the entire power input side, the starting capability of each part of the equipment can be improved. On the other hand, it can also compensate for the voltage drop and harmonic effects caused by active power loss in the line. This avoids the problems of protection malfunction and transformer capacity saturation caused by large reactive power loss and high harmonic ratio in AC power supply lines. With a relatively low cost, the number of transformer relocations can be greatly reduced, thereby improving the efficiency of rapid tunneling.

[0021] 2. This invention extends the power supply distance for tunneling equipment while improving the capacity utilization of mobile transformers and reducing power line losses. By upgrading the power supply network and equipment power consumption scheme on the equipment side, it reduces the capacity and cable costs of mobile transformers. For tunneling equipment, it enhances the flexibility and adaptability of the on-site power grid. Therefore, this invention demonstrates significant technical and economic advantages. Attached Figure Description

[0022] Figure 1 The topology wiring diagram of an intelligent power supply combination switch for a complete set of rapid excavation equipment in an underground coal mine is provided in Embodiment 1 of the present invention;

[0023] Figure 2 This is a topology wiring diagram of a dynamic reactive power compensation device according to an embodiment of the present invention;

[0024] Figure 3 This is a flowchart illustrating the operation method of an intelligent power supply combination switch for a complete set of rapid excavation equipment in an underground coal mine, as provided in Embodiment 2 of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] like Figure 1 As shown, Embodiment 1 of the present invention provides an intelligent power supply combination switch for a complete set of rapid excavation equipment in coal mines, including: an intelligent voltage regulator, multiple dynamic reactive power compensation devices, a first switching switch S1, a second switching switch S6, and multiple third switching switches. The intelligent voltage regulator includes a rectifier stage, an intermediate stage, and multiple inverter stages connected in parallel. The input terminal of the rectifier stage is connected to the output terminal of a mobile transformer, and the output terminal is connected to the input terminal of each inverter stage via the intermediate stage. The output terminal of each inverter stage is connected to a rapid excavation load device. Each rapid excavation load device is provided with a dynamic reactive power compensation device at its input terminal, which is used to dynamically compensate the reactive power of the corresponding rapid excavation load device.

[0028] The output terminal of the mobile transformer is connected to one end of the first switching switch, the other end of the first switching switch is connected to one end of the second switching switch and each of the third switching switches, the other end of each of the third switching switches is connected to a fast excavation load device, and the other end of the second switching switch is connected to other loads.

[0029] In this embodiment, the intelligent voltage regulator is installed at the self-moving tail of the rapid excavation equipment. The 1140V power supply cable from the transformer is connected to the input stage of the intelligent power supply combination switch. Its four output cables are connected in series with the four main devices in the rapid excavation equipment to provide power, thereby playing a dynamic voltage regulation role. Other loads are directly connected to the original power supply line through the second switching switch and the first switching switch. The second switching switch of each branch serves to switch to the original power supply line when the intelligent voltage regulator fails and exits.

[0030] like Figure 2 As shown, the dynamic reactive power compensation device includes a T-type three-level topology and a third-order filter. The third-order filter is a reactance-capacitance-reactance structure. The T-type three-level topology is connected to the input terminal of the corresponding fast-digging load device through the third-order filter.

[0031] Specifically, such as Figure 1As shown, the rectifier stage adopts a diode-clamped three-level topology; the intermediate stage adopts a diode-clamped three-level dual active H-bridge topology, wherein the high-frequency transformer used has a turns ratio of 2:3; and the inverter stage adopts a diode-clamped three-level topology.

[0032] Specifically, such as Figure 1 As shown, in this embodiment, the input terminal of the rectifier stage is provided with a first-order filter formed by reactance, and the output terminal of the inverter stage is provided with a second-order filter composed of reactance and capacitance.

[0033] Specifically, in this embodiment, the control method of the intelligent voltage regulator is as follows: the rectifier stage adopts PWM rectification control, specifically using an outer loop to control the first-stage DC bus voltage and an inner loop to control the amplitude and harmonic components of the grid-connected current. Due to the limitations of the PWM rectification control method, the bus voltage will decrease accordingly as the tunneling distance increases and the input voltage amplitude decreases. The intermediate stage adopts phase-shift control to maintain the second-stage DC bus voltage constant to meet the output requirements of the inverter side. During the movement, the phase shift is adjusted through a closed loop to ensure that the second-stage DC bus voltage remains constant while the first-stage DC bus voltage continuously decreases. Each inverter stage adopts a voltage closed-loop inverter control method, which performs real-time compensation based on the connected load conditions, i.e., based on the voltage at the currently connected load terminal.

[0034] Specifically, in this embodiment, the control method of the dynamic reactive power compensator is as follows: the reactive component in the load current is detected and superimposed on the q-axis component of the current command value output by the outer loop, ensuring that the current command value output by the outer loop quickly and accurately reflects the reactive current component in the load, thereby providing an accurate command value for the inner loop of the circuit control. The proportional control used in the inner current loop will produce periodic errors. To compensate for this control delay and improve current tracking accuracy, a repetitive controller containing internal modes of each harmonic is introduced on the basis of proportional control, forming an inner loop control strategy that combines proportional control and repetitive control in parallel.

[0035] Specifically, in this embodiment, there are four inverter stages, and the fast excavation load equipment includes a roadheader, a bolt transfer machine, a belt transfer machine, and a self-propelled tailstock machine. The output terminals of each inverter stage are connected to the input terminals of the roadheader, bolt transfer machine, belt transfer machine, and self-propelled tailstock machine, respectively. There are four third switching switches, namely S2, S3, S4, and S5.

[0036] Example 2

[0037] like Figure 3 As shown, Embodiment 2 of the present invention provides an operation method for an intelligent power supply combination switch of a complete set of underground rapid excavation equipment in coal mines, including the following steps:

[0038] (1) After receiving the power-on command, first determine whether the first switch, the second switch and the third switch are in the off state. After confirming that they are all in the off state, start the rectifier stage of the intelligent voltage regulator.

[0039] (2) After startup, determine the first-stage DC bus voltage V at the rectifier stage output. P1N1 If the voltage is within the first normal range, start the intermediate stage and proceed to step (3); otherwise, proceed to step (4). The first normal range is related to the AC bus voltage on the input side of the rectifier stage.

[0040] (3) Determine the DC bus voltage V at the output terminal of the intermediate stage. P2N2 If the device is within the second normal range, start the inverter stage and the second switching switch corresponding to each fast-cut load device one by one. After each inverter stage starts successfully, start the dynamic reactive power compensation device corresponding to that inverter stage. After all inverter stages and corresponding dynamic reactive power compensation devices are started, start each device of the fast excavation equipment. If not, proceed to step (4). The second normal range is related to the output voltage of each inverter stage. The starting sequence of each inverter stage is determined according to the operating conditions.

[0041] (4) Close the first switching switch, the second switching switch and each of the third switching switches to start each device of the rapid excavation equipment.

[0042] In this embodiment, when the voltage of two of the DC bus stages is outside the normal range, the intelligent power supply combination switch exits the intelligent mode and closes the six switches S1-S6 to ensure that the equipment can still maintain normal working status.

[0043] In summary, this invention provides an intelligent power supply combination switch and its operation method for a complete set of rapid excavation equipment in coal mines. By using a series intelligent voltage regulator and a parallel reactive power compensator, the invention reduces the difficulty of starting the various motors of the rapid excavation equipment through frequency conversion starting. During normal operation, the parallel reactive power compensator compensates for the voltage drop caused by reactive current in the line between the rapid excavation equipment and the mobile transformer. The series intelligent voltage regulator compensates for the voltage output of the load switch in real time, making up for the voltage drop caused by active current in the line. This ensures that the voltage on the equipment side remains within the allowable operating range of the motor as the excavation distance increases. It also has harmonic mitigation functions for the power supply transmission line at the working face. The use of an intelligent power supply combination switch improves the adaptability of the rapid excavation equipment to the on-site power grid, eliminating the need to move the transformer forward due to power supply voltage issues during tunneling, thus reducing the workload of moving the transformer and effectively increasing the tunneling progress. This achieves "transformer relocation without transformer relocation." A smart power supply combination switch replaces the original combination switch and is installed at the self-moving tail of the rapid tunneling equipment. The power supply cable of the transformer is connected to the input stage of the smart power supply combination switch, and its output stage is connected to the circuit systems of various parts of the rapid tunneling equipment. By activating the corresponding functions according to a predetermined working sequence, the rapid tunneling equipment can be smoothly started when needed. After normal operation, it reduces power line losses and increases the power supply distance. Simultaneously, the device has a bypass function, so fault exit will not affect the normal operation of the rapid tunneling equipment. Therefore, this invention improves the direct starting capability of motors in various components of rapid tunneling equipment in coal mines, extends the power supply distance, and reduces power line losses. It can be applied to various types of tunneling equipment, as well as other multi-motor load integrated mobile equipment with different numbers, voltages, and capacity levels of motors, providing effective distance movement.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 smart power supply combination switch for a complete set of rapid excavation equipment in underground coal mines, characterized in that, include: The system includes an intelligent voltage regulator, multiple dynamic reactive power compensation devices, a first switching switch, a second switching switch, and multiple third switching switches. The intelligent voltage regulator comprises a rectifier stage, an intermediate stage, and multiple inverter stages connected in parallel. The input terminal of the rectifier stage is connected to the output terminal of the mobile transformer, and the output terminal is connected to the input terminal of each inverter stage via the intermediate stage. The output terminal of each inverter stage is connected to a fast excavation load device. Each fast excavation load device has a dynamic reactive power compensation device installed at its input terminal. The dynamic reactive power compensation device is used to dynamically compensate the reactive power of the corresponding fast excavation load device. The output terminal of the mobile transformer is connected to one end of the first switching switch, the other end of the first switching switch is connected to one end of the second switching switch and each of the third switching switches, the other end of each of the third switching switches is connected to a fast excavation load device, and the other end of the second switching switch is connected to other loads; The dynamic reactive power compensation device includes a T-type three-level topology and a third-order filter. The third-order filter is a reactance-capacitor-reactance structure. The T-type three-level topology is connected to the input terminal of the corresponding fast-drilling load device through the third-order filter. The rectifier stage adopts a diode-clamped three-level topology. The intermediate stage adopts a diode-clamped three-level dual active H-bridge topology, wherein the high-frequency transformer ratio is 2:

3. The inverter stage adopts a diode-clamped three-level topology. The input terminal of the rectifier stage is equipped with a first-order filter formed by reactance, and the output terminal of the inverter stage is equipped with a second-order filter composed of reactance and capacitance. The rectifier stage adopts PWM rectification control, the intermediate stage adopts phase shift control, and each inverter stage performs real-time compensation based on the voltage of the currently connected load.

2. The intelligent power supply combination switch for a complete set of rapid underground excavation equipment in coal mines according to claim 1, characterized in that, There are four inverter stages, and the output of each inverter stage is connected to the inlet of the roadheader, the bolt transfer machine, the belt transfer machine, and the self-propelled tail section machine, respectively.

3. The operating method of the intelligent power supply combination switch for a complete set of rapid underground excavation equipment in a coal mine according to claim 1, characterized in that, Includes the following steps: (1) After receiving the power-on command, first determine whether the first switch, the second switch and the third switch are in the off state. After confirming that they are all in the off state, start the rectifier stage of the intelligent voltage regulator. (2) After startup, determine the first-stage DC bus voltage V at the output of the rectifier stage. P1N1 If the condition is within the first normal range, then start the intermediate level and proceed to step (3); otherwise, proceed to step (4). (3) Determine the second-stage DC bus voltage V at the intermediate stage output terminal. P2N2 If it is within the second normal range, start the inverter stage corresponding to each fast excavation load device one by one. After each inverter stage is successfully started, start the dynamic reactive power compensation device corresponding to that inverter stage. After all inverter stages and corresponding dynamic reactive power compensation devices are started, start the second switching switch. After all are started, start each device of the fast excavation complete set of equipment. If not, proceed to step (4). (4) Close the first switching switch, the second switching switch and each of the third switching switches to start each device of the fast excavation equipment.

4. The operating method of the intelligent power supply combination switch for a complete set of rapid underground excavation equipment in a coal mine according to claim 3, characterized in that, The first normal range is related to the AC bus voltage on the input side of the rectifier stage.

5. The operating method of the intelligent power supply combination switch for a complete set of rapid underground excavation equipment in a coal mine according to claim 3, characterized in that, The second normal range is related to the output voltage of each inverter stage.

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