Emergency energy storage power supply system for coal mine key equipment

Abstract

The utility model provides an emergency energy storage power supply system for coal mine key equipment. The emergency energy storage power supply system comprises a four-quadrant high-voltage frequency converter, a low-voltage PCS device and an auxiliary power supply system, the four-quadrant high-voltage frequency converter and the low-voltage PCS device share one phase-shifting transformer, high integration of the emergency energy storage power supply system is guaranteed, the four-quadrant frequency converter controls a load motor through cascade H bridge output, the alternating current side of the low-voltage PCS device is connected with a power grid through the transformer, and the direct current side of the low-voltage PCS device is a super capacitor module. After the main power grid loses power, the low-voltage PCS device provides energy for the four-quadrant high-voltage frequency converter, and continuous operation of the load motor is guaranteed. The four-quadrant frequency converter cabinet and the low-voltage PCS cabinet cooperate with each other to jointly complete energy conversion when the main power grid loses power or recovers power utilization. According to the utility model, a stable emergency energy storage power supply scheme can be provided for coal mine key equipment, and continuous and uninterrupted operation of a load motor is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of emergency power supply, and in particular relates to an emergency energy storage power supply system for key equipment in a coal mine. Background Art

[0002] If the coal mine power supply system is suddenly disconnected due to some special reasons, the load fan will not be able to operate normally, resulting in the accumulation of harmful gases such as gas underground, increasing the occurrence of accidents such as explosions and toxic gas poisoning. If the load fan cannot be restarted in a short time, the probability of such safety accidents will increase. Therefore, the uninterrupted operation of the load fan has gradually become a research focus. Utility Model Content

[0003] In view of the above-mentioned deficiencies in the prior art, the utility model provides an emergency energy storage power supply system for key equipment in a coal mine to solve the above-mentioned technical problems.

[0004] An emergency energy storage power supply system for key equipment in a coal mine comprises a four-quadrant high-voltage frequency converter, a low-voltage PCS device and an auxiliary power supply system; the four-quadrant high-voltage frequency converter and the low-voltage PCS device share a phase-shifting transformer, and the main grid voltage is connected to the four-quadrant high-voltage frequency converter and the low-voltage PCS device via the phase-shifting transformer; the DC side of the low-voltage PCS device is provided with energy by a supercapacitor, and the AC side of the low-voltage PCS device is connected to the phase-shifting transformer; the four-quadrant high-voltage frequency converter controls a load motor through a cascaded H-bridge output.

[0005] When the main control system detects that the main power grid is supplying power normally, the system operates in normal frequency conversion mode, and the low-voltage PCS device operates in grid-connected mode, and can be charged normally.

[0006] When the main control system detects that the main grid loses power, the main control will disconnect the upper switch and send a "power failure" command to the low-voltage PCS device. The device switches from grid-connected mode to off-grid mode. At this time, the low-voltage PCS device provides energy for the four-quadrant high-voltage inverter; the low-voltage PCS device sends a power limit command to the main control, and the main control can appropriately reduce the output frequency of the four-quadrant high-voltage inverter to make the motor power operate within the normal range of the supercapacitor module, thereby ensuring the safety and reliability of the system.

[0007] When the system is operating in an emergency state and detects that the main power grid has resumed power supply, the main control will block the output of the four-quadrant high-voltage inverter, send a "power supply restoration" command to the low-voltage PCS device and close the upper switch. At this time, the low-voltage PCS device switches from off-grid mode to grid-connected mode. After completion, it uploads a successful grid connection command to the main control. The main control will start the four-quadrant high-voltage inverter and start it at high speed, and the load motor will run at the specified frequency.

[0008] Furthermore, the main grid voltage is connected to the phase-shifting transformer via a knife switch, a first contactor, and a second contactor connected in series in sequence; the second contactor is connected in parallel with a buffer resistor; and the four-quadrant high-voltage inverter is connected to the load motor via the third contactor. Here, the second contactor is connected in parallel with a buffer resistor, which effectively plays the role of peak clipping and current limiting, while suppressing the impact current of the low-voltage PCS device and the four-quadrant inverter.

[0009] Furthermore, the phase-shifting transformer is a multi-tap phase-shifting transformer. The multi-tap phase-shifting transformer can be interconnected with the low-voltage PCS device and the four-quadrant inverter, eliminating a series of external wiring, and also provides a favorable medium for the low-voltage PCS device to form a power grid when power is lost.

[0010] Furthermore, the auxiliary power supply system is composed of a three-phase four-wire low-voltage energy storage system, so as to provide 380V power to fans, air conditioners and other equipment when the power grid fails.

[0011] In this application, a low-voltage PCS device is used in conjunction with a four-quadrant frequency converter to ensure that the load fan "does not stop blowing during a power outage". The low-voltage PCS device and the four-quadrant frequency converter are relatively independent and can be used separately as two devices during certain periods of time to improve the utilization efficiency of the equipment.

[0012] The beneficial effect of the utility model is that the emergency energy storage power supply system can ensure the uninterrupted operation of the load fan in the event of a power outage in the coal mine main power grid, and ensure that the underground ventilation system is not disturbed; the four-quadrant inverter and the low-voltage PCS device in the system cooperate with each other to ensure energy-saving operation under normal conditions of the main power grid. At the same time, the low-voltage PCS device will provide energy for the four-quadrant inverter when the power grid loses power, ensuring that the load fan "does not stop when the power is off". The utility model has a clear design concept and low cost, and has a very broad application prospect in the coal mining industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 This is the overall control principle diagram of the utility model;

[0015] Figure 2 This is the control logic diagram for the normal power supply of the main power grid of the utility model;

[0016] Figure 3 It is a control logic diagram of the utility model when the main power grid loses power. DETAILED DESCRIPTION

[0017] As shown in the figure, the utility model provides an emergency energy storage power supply system for key equipment in coal mines, including a four-quadrant high-voltage inverter, a low-voltage PCS device and an auxiliary power supply system; the four-quadrant high-voltage inverter and the low-voltage PCS device share a phase-shifting transformer, and the main grid voltage is connected to the phase-shifting transformer through the knife switch QS1, the first contactor KM1, and the second contactor KM2 connected in series in sequence, and the second contactor is connected in parallel with a buffer resistor; the phase-shifting transformer is a multi-tap phase-shifting transformer. The phase-shifting transformer connects the four-quadrant high-voltage inverter and the low-voltage PCS device; the DC side of the low-voltage PCS device is provided with energy by a supercapacitor, and the AC side of the low-voltage PCS device is connected to the phase-shifting transformer; the four-quadrant high-voltage inverter controls the load motor through the cascaded H-bridge output.

[0018] Furthermore, the auxiliary power supply system is composed of a three-phase four-wire low-voltage energy storage system, so as to provide 380V power to fans, air conditioners and other equipment when the power grid fails.

[0019] like Figure 2 As shown, when the main control system detects that the main power grid is powered normally, the system operates in normal frequency conversion mode, and the low-voltage PCS device operates in grid-connected mode and can be charged normally.

[0020] like Figure 3 As shown in the figure, when the main control system detects that the main grid loses power, the main control will disconnect the upper switch, that is, disconnect the first contactor KM1 and the second contactor KM2, and at the same time send a "power failure" command to the low-voltage PCS device, and the low-voltage PCS device switches from the grid-connected mode to the off-grid mode. At this time, the low-voltage PCS device provides energy for the four-quadrant high-voltage inverter; the low-voltage PCS device sends a power limit command to the main control, and the main control can appropriately reduce the output frequency of the four-quadrant high-voltage inverter, so that the load motor power runs within the normal range of the supercapacitor module, ensuring the safety and reliability of the system.

[0021] When the system is in emergency mode and detects that the main power grid has resumed power supply, Figure 3 Towards Figure 2 The operation mode is switched. Specifically, the main control blocks the output of the four-quadrant high-voltage inverter, sends a "power supply restoration" command to the low-voltage PCS device and closes the upper switch; that is, closes the first contactor KM1 and the second contactor KM2. At this time, the low-voltage PCS device switches from off-grid mode to grid-connected mode. After completion, it uploads the grid-connected success command to the main control. The main control starts the four-quadrant high-voltage inverter and starts it at high speed. The load motor runs at the specified frequency.

Claims

1. An emergency energy storage power supply system for key equipment in coal mines, characterized in that: It includes a four-quadrant high-voltage inverter, a low-voltage PCS device and an auxiliary power supply system; the four-quadrant high-voltage inverter and the low-voltage PCS device share a phase-shifting transformer, and the main grid voltage is connected to the four-quadrant high-voltage inverter and the low-voltage PCS device via the phase-shifting transformer; the DC side of the low-voltage PCS device is provided with energy by a supercapacitor, and the AC side of the low-voltage PCS device is connected to the phase-shifting transformer; the four-quadrant high-voltage inverter controls the load motor through the cascaded H-bridge output.

2. The emergency energy storage power supply system for key equipment in coal mines according to claim 1 is characterized in that: The main grid voltage is connected to the phase-shifting transformer via a knife switch, a first contactor and a second contactor connected in series in sequence; a buffer resistor is connected in parallel to the second contactor; and the four-quadrant high-voltage frequency converter is connected to the load motor via the third contactor.

3. The emergency energy storage power supply system for key equipment in coal mines according to claim 1 is characterized in that: The phase-shifting transformer is a multi-tap phase-shifting transformer.

4. The emergency energy storage power supply system for key equipment in coal mines according to claim 1 is characterized in that: The auxiliary power supply system consists of a three-phase four-wire low-voltage energy storage system.

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