Coal mine underground heading machine equipment power quality treatment device and operation method

Abstract

The present application belongs to the technical field of power quality treatment of coal mine underground tunneling machine equipment, discloses a power quality treatment device and operation method of coal mine underground tunneling machine equipment, which comprises a treatment module, a current transformer and a control module, the treatment module comprises a T-type three-level module and an LCL three-order filter module, the treatment module is connected in parallel with the tunneling machine power cable, and the power level is matched with the peak power during the tunneling machine operation; the current transformer is arranged at the three-phase power input end of the tunneling machine; and the control module is used for controlling the treatment module to switch between the pure reactive power compensation mode and the reactive power and harmonic simultaneous compensation mode. The present application reduces the displacement capacity, improves the adaptability of the tunneling machine equipment to the underground power grid, and saves energy and reduces consumption.

Description

Technical Field

[0001] This invention belongs to the field of power supply technology for underground tunneling machines in coal mines, specifically relating to a power quality management device and operating method for underground tunneling machines in coal mines, used for the operation control of reactive power compensation and harmonic control functions in multi-motor equipment. Background Technology

[0002] As the power of underground tunneling machines in coal mines gradually increases, the requirements for the tunneling distance in a single pass also increase. Due to the limitations of transformer capacity and voltage regulation range in the underground power supply system, the motor in the tunneling machine will experience an overload current several times its rated current when starting, resulting in a large amount of reactive power. This reactive power lowers the voltage at the tunneling equipment terminals, making it difficult to start the equipment. The current approach is to shorten the distance between the transformer and the tunneling machine, thereby reducing the voltage drop caused by reactive power in the power supply line and ensuring that the voltage at the tunneling machine terminals remains within the allowable voltage range for startup.

[0003] To improve the efficiency of tunneling operations and reduce the number of relocations, it is necessary to improve the power quality of the tunneling machine's power supply, thereby increasing the efficiency of tunneling work and achieving energy conservation and consumption reduction. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the existing technology, and the technical problem to be solved is: to provide a power quality management device and operation method for underground tunneling machine equipment in coal mines, so as to improve the efficiency of tunneling work and achieve the effect of energy saving and consumption reduction.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a power quality management device for a coal mine underground tunneling machine, comprising a management module, a current transformer, and a control module. The management module includes a T-type three-level module and an LCL third-order filter module. The input line of the management module is connected in parallel with the power supply cable of the tunneling machine, and the power level is matched with the peak power of the tunneling machine during operation. The current transformer is installed at the three-phase power input terminal of the tunneling machine.

[0006] The control module is used to control the governance module to switch between pure reactive power compensation mode and simultaneous reactive power and harmonic compensation mode.

[0007] In the pure reactive power compensation mode, the d-axis current component The current is obtained through bus voltage regulation in the governance module; the 0-axis current component Δi'0 is obtained through bus voltage equalization control; the q-axis current component... The d-axis current component is obtained through reactive power component detection. q-axis current component The 0-axis current component Δi'0 is transformed into the fundamental active current through the dq0→abc coordinate transformation matrix, which serves as the command value for the inner current loop.

[0008] In the simultaneous reactive harmonic compensation mode, the d-axis current component The current component equals the sum of the current component obtained from bus voltage stabilization and the fundamental active component. The 0-axis current component Δi'0 is obtained through bus voltage equalization control, and the q-axis current component... For a specified value, the d-axis current component q-axis current component After the 0-axis current component Δi'0 is transformed into the fundamental active current through the dq0→abc coordinate transformation matrix, the difference between the actual load current and the fundamental active current is used as the current inner loop command value i. c * .

[0009] Busbar equalization is to make u dcn with u dcp The difference is sent to the PI controller to complete the process; u dcn u represents the capacitor voltage from the positive terminal P to the zero terminal O of the governance module. dcn This represents the capacitor voltage from the zero terminal O to the negative terminal N of the governance module.

[0010] Both the pure reactive power compensation mode and the simultaneous reactive power and harmonic compensation mode adopt voltage and current dual closed-loop control, with voltage control being the outer loop, to achieve bus voltage equalization control and voltage stabilization control.

[0011] The coordinate transformation matrix from dq0 to abc is:

[0012]

[0013] in, The phase angle is obtained by the governance module through phase-locking the AC bus voltage.

[0014] In the reactive harmonic simultaneous compensation mode, the q-axis current component Specify 0 or i q The specified value is switched by a reactive power command switching switch.

[0015] Furthermore, the present invention also provides a method for operating underground tunneling equipment in coal mines, based on the aforementioned treatment device, comprising the following steps:

[0016] (1) Determine whether the pump station motor is allowed to start. If so, start the pump station motor and control the treatment module to run in pure reactive power compensation mode.

[0017] (2) After the pump station motor starts, determine whether its input current meets the normal operating conditions. If so, run the governance module in the reactive harmonic compensation mode and then start the transport motor.

[0018] (3) After the transport motor is working normally, determine whether the cutting motor is allowed to start. If so, start the cutting motor and control the governance module to run in pure reactive power compensation mode.

[0019] (4) After the cutting motor starts, determine whether its input current meets the normal operating conditions. If so, control the governance module to operate in the reactive harmonic compensation mode.

[0020] In step (2), the specific method for determining whether the input current meets the normal operating conditions is as follows: continuously monitor the input current of the pump station motor. If the input current does not exceed the rated current for 1 minute, it is determined that the normal operating conditions are met.

[0021] In step (4), the specific method for determining whether the input current meets the normal operating conditions is as follows: continuously detect the input current of the cutting motor. If the input current does not exceed the rated current for 1 minute, it is determined that the normal operating conditions are met.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention provides a power quality management device and operating method for underground tunneling machines in coal mines. By adding a power quality management device to the tunneling machine, the starting capability of the tunneling machine can be improved, and the power supply line loss and harmonic effects can be reduced. This avoids problems such as malfunction of protection devices and overheating caused by saturation of mobile transformers due to high reactive power loss and high harmonic ratio in the power supply line. With a relatively low cost increase in the tunneling machine equipment, the efficiency of tunneling work is improved, achieving energy saving and consumption reduction, demonstrating significant technical and economic advantages.

[0024] 2. This invention extends the power supply distance of tunneling machine equipment, improves the capacity utilization of mobile transformers, and reduces power supply line losses. It upgrades and transforms the power supply network and equipment power consumption scheme on the equipment side, reducing the capacity cost and cable cost of mobile transformers. For tunneling machine equipment, it improves the ability to adapt to different underground power grids. This invention is also applicable to the power supply of other similar equipment. Attached Figure Description

[0025] Figure 1 An electrical connection diagram of a power quality management device and a tunneling machine provided in an embodiment of the present invention;

[0026] Figure 2 This is a control block diagram of the power quality management device in an embodiment of the present invention;

[0027] Figure 3 This is a block diagram of the power supply operation strategy in an embodiment of the present invention. Detailed Implementation

[0028] 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.

[0029] Example 1

[0030] like Figure 1 As shown, Embodiment 1 of the present invention provides a power quality management device for underground tunneling machines in coal mines, including a management module, a current transformer, and a control module. The management module includes a T-type three-level module and an LCL third-order filter module. The input line of the management module is connected in parallel with the power supply cable of the tunneling machine, and its power rating matches the peak power of the tunneling machine during operation. The current transformer is installed at the three-phase power input terminal of the tunneling machine and is used to measure the total three-phase input current i of the tunneling machine equipment. load The control module is used to control the switching of the treatment module between pure reactive power compensation mode and simultaneous reactive power and harmonic compensation mode. The treatment module is fixed to the tail of the tunneling machine and moves with the tunneling machine.

[0031] The bus voltage between the positive terminal P and the negative terminal N of the DC bus in the power quality management device is u. dc u dc =u dcp +u dcn , where u dcp The voltage across the capacitor from the positive terminal P to the zero terminal O, u dcn The voltage across the capacitor from terminal O to terminal N is i. inv The output current of the treatment device, u inv The inverter voltage of the treatment device; i load i is the total three-phase input current of the tunneling machine equipment. load =i cut +i pump +i trans , where i cut i is the three-phase input current of the cutting motor in the tunneling machine. pump i represents the three-phase input current of the pump station motor in the tunneling machine. trans The three-phase input current of the transport motor in the tunneling machine is obtained by measuring the current transformers in their respective circuits.

[0032] like Figure 2 As shown, in the pure reactive power compensation mode, the d-axis current component The current is obtained through bus voltage regulation in the governance module; the 0-axis current component Δi'0 is obtained through bus voltage equalization control; the q-axis current component... The d-axis current component is obtained through reactive power component detection. q-axis current component The 0-axis current component Δi'0 is transformed into the fundamental active current via the dq0→abc coordinate transformation matrix, which serves as the inner current loop command value i. c * ;

[0033] In the simultaneous reactive harmonic compensation mode, the d-axis current component The current component equals the sum of the current component obtained from bus voltage stabilization and the fundamental active component. The 0-axis current component Δi'0 is obtained through bus voltage equalization control, and the q-axis current component... For a specified value, the d-axis current component q-axis current component After the 0-axis current component Δi'0 is transformed into the fundamental active current through the dq0→abc coordinate transformation matrix, the difference between the actual load current and the fundamental active current is used as the current inner loop command value i. c * .

[0034] like Figure 2 As shown, where The phase angle obtained by the control device through phase-locking with the AC bus voltage is shown in the figure. Δθ in the figure represents the phase delay caused by sampling and control of the control device. (d-axis variable) The active current component required for the normal operation of the power supply is generated by the voltage outer loop control. It dissipates during the switching and conduction processes of each device in the converter, and is crucial for establishing the DC-side voltage in rectification mode. It is also an effective means of stabilizing the total DC-side voltage when the converter is in compensation mode. For voltage equalization control, it involves... dcn with u dcp The difference is fed into the PI controller, and its output 0-axis component Δi'0 must ensure that the line current in the converter is as small as possible, while ensuring the DC-side capacitor voltage is balanced, taking into account both voltage equalization and compensation effects. (q-axis component) The current command value is obtained through reactive component detection, or specified as any value within a certain range. Then, the current command value in the dq0 coordinate system is transformed into the command current value in the abc coordinate system. The dq0→abc coordinate transformation matrix is:

[0035]

[0036] in, The phase angle is obtained by the phase-locked loop of the AC bus voltage by the governance module. When considering the phase delay, the middle of formula (1) Replaced with

[0037] Specifically, in this embodiment, both the pure reactive power compensation mode and the simultaneous reactive power and harmonic compensation mode employ dual closed-loop control of voltage and current. Voltage control is the outer loop, achieving bus voltage equalization and stabilization control. Current control, depending on the compensation mode, is divided into detecting the reactive component and the fundamental active component in the load current.

[0038] Specifically, in this embodiment, when using the pure reactive power compensation mode, 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. This ensures that the reactive current component in the load current is quickly and accurately fed back into the current command value output by the outer loop, thereby providing an accurate command value for the inner current loop. When using the simultaneous reactive power and harmonic compensation mode, the fundamental active component in the load current is detected and superimposed on the d-axis component of the current command. This, along with the 0-axis component formed by voltage equalization control and the component designated as the q-axis, forms the fundamental active current. Then, the actual load current is subtracted from this fundamental active current to obtain the current command value that compensates for the components other than the fundamental active component. This refers to the output current reference value of the power quality management device, which is the fundamental reactive component plus the harmonic components used as the current command value output by the voltage outer loop. The proportional control used in the current inner loop will produce periodic errors. To compensate for this control delay and improve current tracking accuracy, this embodiment introduces a repetitive controller containing the internal modes of each harmonic on top of the proportional control, forming an inner loop control strategy that combines proportional control and repetitive control in parallel. Finally, through SPWM carrier modulation, the control duty cycle d of each switching device in the output management module is determined. 1～12 .

[0039] Furthermore, in this embodiment, the reactive power compensation capacity i can be specified according to the operating conditions of the tunneling machine. q The value is used to allocate the respective capacities of reactive power and harmonics in the reactive power and harmonics compensation mode.

[0040] Specifically, in this embodiment, bus equalization is to... dcn with u dcp The difference is sent to the PI controller to complete the process; u dcn u represents the capacitor voltage from the positive terminal P to the zero terminal O of the governance module. dcn This represents the capacitor voltage from the zero terminal O to the negative terminal N of the governance module.

[0041] Furthermore, such as Figure 2 As shown in this embodiment, in the reactive harmonic simultaneous compensation mode, the q-axis current component... Specify 0 or i q The specified value can be switched by using a reactive power command switching switch.

[0042] Example 2

[0043] like Figure 3 As shown, Embodiment 2 of the present invention provides a method for operating underground tunneling equipment in coal mines, based on the treatment device described in Embodiment 1, including the following steps:

[0044] (1) Determine whether the pump station motor is allowed to start. If so, start the pump station motor and control the treatment module to run in pure reactive power compensation mode.

[0045] (2) After the pump station motor starts, determine whether its input current meets the normal operating conditions. If so, run the governance module in the reactive harmonic compensation mode and then start the transport motor.

[0046] Based on the composition and operating characteristics of the tunneling machine, the first step is to determine whether the pump station motor is allowed to start. During startup, the parallel-connected control device operates in pure reactive power compensation mode (Mode 1), with its entire capacity used to provide the reactive power required for the tunneling machine's pump station motor to start. Under the premise of meeting the startup rate, the pump station motor starts smoothly. After startup, the input current of the pump station motor is continuously monitored. Once the conditions for normal operation are met, i.e., the input current does not exceed the rated current for more than 1 minute, the reactive power in the line decreases, and the control module operates in reactive power and harmonics simultaneous compensation mode (Mode 2). The capacity of the control module is used to compensate for both reactive power and harmonics. At this time, the control module does not explicitly distinguish the percentage of capacity used for reactive power and harmonics compensation. When it is necessary to adjust the ratio of the two, in the reactive power and harmonics simultaneous compensation mode, the q-axis current component can be adjusted through the reactive power command switching switch by specifying the reactive current component i. q The size of the value is determined to achieve accurate compensation and control of reactive components and harmonics in the simultaneous reactive harmonic compensation mode. This is suitable for situations requiring precise control of harmonic content or improvement of power factor.

[0047] Since the power of the transport motor in a typical tunneling machine is not large, and is an order of magnitude smaller than that of the pump station motor and the cutting motor, it is not necessary to distinguish between startup and normal operation. The power supply can be directly supplied according to the reactive power and harmonic compensation mode.

[0048] (3) After the transport motor is working normally, determine whether the cutting motor is allowed to start. If so, start the cutting motor and control the governance module to run in pure reactive power compensation mode.

[0049] (4) After the cutting motor starts, determine whether its input current meets the normal operating conditions. If so, control the governance module to operate in the reactive harmonic compensation mode.

[0050] In step (3), by controlling the governance module to operate in pure reactive power compensation mode, the reactive power required for the start-up of the cutting motor is enhanced. After the normal operating conditions are met, the module smoothly switches from mode 1 to mode 2 and continues to wait for the next start-up of the cutting motor or the shutdown and restart of the tunneling machine.

[0051] In step (4), the specific method for determining whether the input current meets the normal operating conditions is as follows: continuously detect the input current of the cutting motor. If the input current does not exceed the rated current for 1 minute, it is determined that the normal operating conditions are met.

[0052] In this embodiment, the operation switching strategy is closely related to the operating conditions of the tunneling machine. Different operation control strategies are adopted in different operating conditions, and a smooth switching is achieved by setting the tracking rate of the inner loop current command value during the switching process between the two control strategies.

[0053] This invention provides a power quality management device and operating method for underground tunneling machines in coal mines. It is primarily designed to improve the direct starting capability of motors in various components of the tunneling machine, increase power supply distance, and reduce power line losses. It employs a novel power quality management strategy, extending the power supply distance of the tunneling machine while improving the capacity utilization of mobile transformers and reducing power line losses. This represents an upgrade to the power supply network and equipment power consumption scheme on the equipment side, reducing the capacity and cable costs of mobile transformers. For tunneling machines, it enhances their adaptability to different underground power grids. It is also applicable to the power supply of other similar equipment, such as equipment containing asynchronous motors of varying numbers, voltages, and capacity levels.

[0054] 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 power quality management device for underground tunneling machines in coal mines, characterized in that, The system includes a governance module, a current transformer, and a control module. The governance module includes a T-type three-level module and an LCL third-order filter module. The power input of the governance module is connected in parallel with the power supply cable of the tunneling machine, and its power rating is matched with the peak power of the tunneling machine during operation. The current transformer is located at the three-phase power input terminal of the tunneling machine. The control module is used to control the governance module to switch between pure reactive power compensation mode and simultaneous reactive power and harmonic compensation mode. In the pure reactive power compensation mode, the d-axis current component The current is obtained through bus voltage regulation in the governance module; the 0-axis current component Δi'0 is obtained through bus voltage equalization control; the q-axis current component... The d-axis current component is obtained through reactive power component detection. q-axis current component The 0-axis current component Δi'0 is transformed into the fundamental active current via the dq0→abc coordinate transformation matrix, which serves as the inner current loop command value i. c * ; In the simultaneous reactive harmonic compensation mode, the d-axis current component The current component equals the sum of the current component obtained from bus voltage stabilization and the fundamental active component. The 0-axis current component Δi'0 is obtained through bus voltage equalization control, and the q-axis current component... For a specified value, the d-axis current component q-axis current component After the 0-axis current component Δi'0 is transformed into the fundamental active current through the dq0→abc coordinate transformation matrix, the difference between the actual load current and the fundamental active current is used as the current inner loop command value i. c * .

2. The power quality management device for underground tunneling machines in coal mines according to claim 1, characterized in that, Busbar equalization is to make u dcn with u dcp The difference is sent to the PI controller to complete the process; u dcn u represents the capacitor voltage from the positive terminal P to the zero terminal O of the governance module. dcn This represents the capacitor voltage from the zero terminal O to the negative terminal N of the governance module.

3. The power quality management device for underground tunneling machines in coal mines according to claim 1, characterized in that, Both the pure reactive power compensation mode and the simultaneous reactive power and harmonic compensation mode adopt dual closed-loop control of voltage and current, with voltage control being the outer loop, to achieve bus voltage equalization control and voltage stabilization control.

4. The power quality management device for underground tunneling machines in coal mines according to claim 1, characterized in that, The coordinate transformation matrix from dq0 to abc is: in, The phase angle is obtained by the governance module through phase-locking the AC bus voltage.

5. The power quality management device for underground tunneling machines in coal mines according to claim 1, characterized in that, In the reactive harmonic simultaneous compensation mode, the q-axis current component Specify 0 or i q The specified value is switched by a reactive power command switching switch.

6. A method for operating a coal mine underground tunneling machine, implemented based on the treatment device described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Determine whether the pump station motor is allowed to start. If so, start the pump station motor and control the treatment module to run in pure reactive power compensation mode. (2) After the pump station motor starts, determine whether its input current meets the normal operating conditions. If so, run the governance module in the reactive harmonic compensation mode and then start the transport motor. (3) After the transport motor is working normally, determine whether the cutting motor is allowed to start. If so, start the cutting motor and control the governance module to run in pure reactive power compensation mode. (4) After the cutting motor starts, determine whether its input current meets the normal operating conditions. If so, control the governance module to operate in the reactive harmonic compensation mode.

7. The method for operating a coal mine underground tunneling machine according to claim 6, characterized in that, In step (2), the specific method for determining whether the input current meets the normal operating conditions is as follows: continuously monitor the input current of the pump station motor. If the input current does not exceed the rated current for 1 minute, it is determined that the normal operating conditions are met.

8. The method for operating a coal mine underground tunneling machine according to claim 6, characterized in that, In step (4), the specific method for determining whether the input current meets the normal operating conditions is as follows: continuously detect the input current of the cutting motor. If the input current does not exceed the rated current for 1 minute, it is determined that the normal operating conditions are met.

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