High-voltage frequency conversion system for emergency lifting under whole mine power failure

Abstract

The invention belongs to the technical field of mine hoist control, and provides a high-voltage frequency conversion system for emergency hoisting under whole mine power failure, which mainly comprises a three-phase emergency power supply capable of controlling charging and three groups of n-stage serially connected power units capable of controlling charging, a storage battery or a super-capacitor battery cell capable of being charged and discharged repeatedly is arranged inside, and during normal lifting, the battery cell automatically stores electricity; when the whole mine is powered off, the fully-charged three-phase emergency power supply provides control electricity for the whole system, the fully-charged power unit provides power electricity for the lifting motor, emergency lifting is carried out through the high-voltage frequency conversion system, passengers trapped in a shaft can be safely evacuated to the ground, a battery cell of a proper specification is selected and matched, long-time endurance can be achieved, and safety and reliability are achieved. And multiple times of emergency lifting-lowering circulation are carried out. The battery cell can store electricity, flat waves and filter waves, the use of the device is optimized, the charging and discharging current of the battery cell is controlled within an allowable range, and the service life of the battery cell is prolonged. The method has remarkable social and economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of mine hoist control, and specifically proposes a high-voltage frequency conversion system for emergency hoisting under power outage of the entire mine. Background Art

[0002] Underground mines usually have dual-circuit power supply, but due to irresistible "natural disasters" or unexpected "man-made disasters", mine-wide power outages often occur; in the event of a mine-wide power outage, the mine hoist is forced to shut down, and the occupants in the cage are trapped in the shaft; other workers underground are also unable to evacuate safely through the mine hoist; at the same time, the mine-wide power outage causes ventilation, drainage and other facilities to be unable to operate, especially in high-gas and water-rich mines, where emergency rescue activities cannot be effectively carried out and will face serious safety hazards.

[0003] A well-known practice is to use gravity sliding, whereby the mine hoist slides toward the heavier side by means of the tension difference between the two lifting containers, and the passengers trapped in the shaft are slid to a relatively safe position by loosening or tightening the disc brake of the mine hoist. The gravity sliding process has many uncertainties and may create new unforeseen dangers. As a last resort, the "gravity sliding" method cannot be used.

[0004] Another well-known practice is to use a backup emergency power supply, which is usually a high-voltage diesel generator set, a high-voltage emergency energy storage power supply, etc., such as the published patents "Integrated High-Voltage Cascade Energy Storage System" (CN 215267793 U), "A New Topology Structure of Energy Storage Type High-Voltage Frequency Converter Device" (CN 215186455 U), etc.; due to the large installed capacity of the auxiliary shaft hoist, a certain margin is required, and the installed capacity of the backup emergency power supply is required to be thousands of kilowatt-hours or more. The one-time investment and operation and maintenance costs, including management costs, are high, the economy is poor, and it is not easy to promote.

[0005] The traditional four-quadrant high-voltage inverter dedicated to mine hoists has electrolytic capacitors or non-polar capacitors installed in its power unit which are mainly used for smoothing and filtering. In the event of a power outage, these capacitors will unload the limited electrical energy in a short time and cannot provide power. Therefore, the main circuit of the known high-voltage inverter may also have the function of an uninterruptible power supply UPS, such as the disclosed patent "A high-voltage inverter with UPS" (CN102983753A). It is not for the high-voltage inverter to output high-voltage power in the event of a power outage, but only to solve power supply quality problems such as power shaking (instantaneous voltage drop) and interference in the power grid.

[0006] Mine hoists need to frequently accelerate and decelerate during the process of lifting and lowering to perform four-quadrant operation, precise frequency regulation and positioning. Fans and water pumps use high-voltage inverters mainly for soft starting, which can be switched to industrial frequency (50Hz) operation after soft starting. The published patent "A high-voltage energy storage power unit with uninterrupted power supply" (CN221282891U) and the patent "A high-voltage energy storage inverter control system and method" (CN117060460A) based on it are only applicable to two-quadrant loads such as coal mine fans and water pumps, and cannot be applied to mine hoists. Its power unit uses an "uncontrolled rectifier module". In order to realize the storage and release of battery cluster energy, a DCDC unit must be added. Boost is performed through a reactor and a pair of IGBTs. The inverter unit, DCDC unit and energy storage battery together constitute a high-voltage energy storage variable frequency power unit with overlapping function settings, complex circuits, high cost and large size. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a high-voltage frequency conversion system for emergency lifting under power outage of the whole mine, which is equipped with a battery cell that can be repeatedly charged and discharged. Under normal power supply, the high-voltage frequency conversion system cooperates with the mine hoist control system to perform normal lifting while the built-in controllable charging three-phase emergency power supply and controllable charging power unit of the high-voltage frequency conversion system automatically store electricity; under power outage of the whole mine, the fully charged three-phase emergency power supply not only provides control power for the high-voltage frequency conversion system, but also provides control power for the mine hoist control system; similarly, the fully charged power unit can still provide power for the mine hoisting motor; under power outage of the whole mine, emergency lifting is carried out with the help of the high-voltage frequency conversion system of the present invention, which can not only safely evacuate the occupants trapped in the shaft to the ground, but also can last for a long time according to the design capacity and perform multiple lifting-lowering cycles to meet the needs of emergency rescue; during the controllable charging process, the charging current of the battery cell is within the allowable range, which helps to extend the service life of the battery cell.

[0008] The present invention adopts the following technical solutions to achieve its invention purpose: A high-voltage frequency conversion system for emergency lifting during a power outage in the entire mine, the high-voltage frequency conversion system is provided with a controllably rechargeable three-phase emergency power supply and three groups of controllably rechargeable power units connected in series at n levels; the controllably rechargeable three-phase emergency power supply and the power unit are provided with battery cells; a three-phase auxiliary winding is provided on the secondary side of a rectifier transformer corresponding to the controllably rechargeable three-phase emergency power supply; the secondary side of the rectifier transformer is also provided with 3*n windings for supplying power to the power unit; an output end u1 of the three-phase auxiliary winding is connected to an input end of a controllably rechargeable three-phase emergency power supply to supply power to the controllably rechargeable three-phase emergency power supply and charge the battery cells therein online at the same time; an output end u2 of the controllably rechargeable three-phase emergency power supply is connected to one power input end of a high-voltage frequency conversion main control cabinet, and another power input end of the high-voltage frequency conversion main control cabinet is connected to a network control circuit u1. k The two control circuits are connected to form a double-circuit input control power of the high-voltage frequency conversion main control cabinet; a conversion switch is provided in the high-voltage frequency conversion main control cabinet for switching the double-circuit control power, which is connected to the mine hoist control system after switching by the conversion switch, so that the mine hoist control system has a double-circuit control power; the conversion switch has two positions, "normal" and "emergency"; when the conversion switch is in the "normal" position, the main control cabinet and the mine hoist control system are both controlled by the network control power u k In addition, the main control cabinet is connected to the mine hoist control system through communication or point-to-point connection. The main control cabinet receives the instructions of the mine hoist control system and transmits the operating status and parameters of the high-voltage frequency conversion system including fault information to the mine hoist control system. The O1 terminals of the three groups of first-stage power units are connected together to form a three-phase high-voltage power supply. o The output neutral point Q0, three groups of n-level controllable charging power units are connected in series in the order of O2-O1, and the O2 ends of the three groups of n-level power units are connected to the three-phase input ends of the lifting motor respectively, providing the lifting motor with three-phase high-voltage power u with adjustable frequency and voltage o ; The three-phase input ends of the three groups of n-level controllable charging power units are respectively connected to the output ends of the corresponding secondary windings of the rectifier transformer to provide power electricity for the power units and charge the batteries therein online. In addition, the three groups of n-level controllable charging power units are connected to the main control cabinet through optical fibers. The power units receive instructions from the main control cabinet and transmit the working status and parameters of the power units, including fault information, to the main control cabinet; the three phases of the primary winding of the rectifier transformer are respectively connected to one end of the three phases of the high-voltage contactor, and the other end of the high-voltage contactor is respectively connected to the power supply u from the network. i Three-phase connection The three phases of the high voltage contactor are connected to the charging current limiting resistor, and the high voltage frequency conversion system of the present invention receives the network power u iInitially, all built-in battery cells are charged with current limiting. The coil of the high-voltage contactor is connected to the control interface of the main control cabinet, and the on and off of the high-voltage contactor is controlled by the main control cabinet. When the network power supply is normal, the network power supply u i Through the high-voltage frequency conversion system, the output frequency and voltage are adjustable. o Drive the lifting motor to complete the normal lifting task, charge all the batteries built into the three-phase emergency power supply of the controllable charge and the three groups of n-level series-connected controllable charge power units online; in the event of a power outage in the entire mine, that is, u i =0,u k =0, the conversion switch in the main control cabinet is placed in the "emergency" position, the three-phase emergency power supply with fully charged cells provides control power for the main control cabinet and the mine hoist control system, and the three groups of n-level series-connected controllable power units with fully charged cells provide power for the hoisting motor. o , ensuring that the mine hoist can carry out emergency lifting when the whole mine is out of power. Its endurance depends on the capacity of the battery cell and can be designed and selected.

[0009] The controllable and rechargeable three-phase emergency power supply is mainly composed of a group of battery cells connected in series, a DC current sensor, a DC voltage sensor, a DC switching power supply, a power control board, a three-phase controllable front end and its driving board, a three-phase inverter bridge and its driving board; a group of the battery cells connected in series are connected in series with the DC current sensor, and then connected in parallel with the DC voltage sensor, the three-phase controllable front end and the three-phase inverter bridge to form DC1+ and DC1- poles, the input end of the DC switching power supply is connected to DC1+ and DC1-, and the output end of the DC switching power supply is connected to the power input end of the power control board to provide working power for the power control board, the three-phase controllable front end driving board and the three-phase inverter bridge driving board; it can be seen that the internal working power supply of the controllable and rechargeable three-phase emergency power supply only depends on a group of the battery cells connected in series, and is not affected by external The controllable charging three-phase emergency power supply can output voltage u2 and frequency 50Hz under the action of a group of the battery cells connected in series and fully charged, so as to meet the demand of providing control power for emergency lifting of the high-voltage frequency conversion main control cabinet and the mine hoist control system in the case of a power outage in the whole mine; the secondary signal lines of the DC current sensor and the DC voltage sensor are connected to the power control board, which is used for charging and discharging control of a group of the battery cells connected in series, current and voltage detection, and historical parameter recording; the power control board is connected to the main control cabinet through optical fiber, and the three-phase emergency power supply receives instructions from the main control cabinet, and transmits the working status and parameters of the three-phase emergency power supply including fault information to the main control cabinet.

[0010] The controllable charging power unit is mainly composed of at least one group of battery cells connected in series and their DC current sensors, DC voltage sensors, DC switching power supplies, unit control boards, three-phase controllable front ends and their driving boards, and single-phase inverter bridges and their driving boards; at least one group of battery cells connected in series and their DC current sensors are connected in parallel with the DC voltage sensors, three-phase controllable front ends, and single-phase inverter bridges to form DC2+ and DC2- poles, the input end of the DC switching power supply is connected to DC2+ and DC2-, and the output end of the DC switching power supply is connected to the power input end of the unit control board to provide working power for the unit control board, the three-phase controllable front end driving board, and the single-phase inverter bridge driving board. It can be seen that the internal working power supply of the controllable charging power unit only depends on at least one group of the battery cells connected in series, and is not affected by the on / off status of the external power supply. Even if the input end of the power unit is powered off, under the action of at least one group of the battery cells connected in series, the power unit can still output single-phase AC power with adjustable frequency and voltage according to the requirements of the main control cabinet. The three groups of controllable charging power units connected in series at n levels can output three-phase high-voltage power with adjustable frequency and voltage. o , driving the lifting motor to operate, meeting the needs of normal lifting and emergency lifting in the event of a power outage in the entire mine; the secondary signal lines of the DC current sensor and DC voltage sensor are connected to the unit control board, which is used for the built-in battery cell charging and discharging control, current and voltage detection, and historical parameter recording.

[0011] The battery cell used is a repeatedly chargeable and dischargeable battery cell, or a supercapacitor cell, and its structure is similar to that of a commonly used electrolytic capacitor or a non-polar capacitor, and has capacitor characteristics. It is used in the controllably chargeable three-phase emergency power supply and power unit, and its main function is to store electricity, and it also has smoothing and filtering effects. The use of components is optimized, which can reduce costs, equipment size, and operation and maintenance costs.

[0012] Under normal power supply conditions, the charging process of the battery cell is controlled by the voltage and current double closed-loop PI (proportional integral) in the control board. For this purpose, the control board is provided with a voltage loop comparator, a voltage loop PI regulator, a current loop comparator, a current loop PI regulator, etc. The adjustment signals output by the double closed loops act on the three-phase controllable front end through the corresponding driving board to perform PWM voltage regulation, and the charging of the built-in battery cell is controlled respectively. The charging process is divided into three stages: current limiting charging, constant current charging, and constant voltage charging, which are described as follows: 1) In the current limiting charging stage, at time t0, the high-voltage frequency conversion system receives the network power (u i is 6kV or 10kV), the high voltage contactor is in open circuit state, u iAfter the voltage is divided by the charging current limiting resistor, the voltage applied to the primary winding of the rectifier transformer is a smaller value, and the three-phase rectifier bridge rectifier composed of the auxiliary winding, the secondary winding, and the diodes connected in parallel in the power devices of the three-phase controllable front end is rectified. Assuming that the DC 1+ 、DC 1- The voltage across the two ends is U d10 , D.C. 2+ 、DC 2- The voltage across the two ends is U d20 , greater than the total residual voltage value U of the cells connected in series d11 , U d21 When (U d10 >U d11 , U d20 >U d21 ), the battery cells connected in series are charged with current limiting. If the current is less than the total residual voltage value U of the battery cells connected in series, d11 , U d21 When (U d10 d11 , U d20 d21 ), it directly enters the constant current charging stage of controllable charging; the design requirement is that the input voltage is U d10 and U d20 , the DC switching power supply can work normally and provide working power for the control board and the drive board. 2) Constant current charging stage, at time t1, the main control cabinet instructs the high-voltage contactor to close, short-circuit the parallel charging current limiting resistor, and the network power u i Directly applied to the primary winding of the rectifier transformer, the auxiliary winding and the secondary winding of the rectifier transformer both output rated voltage; in the voltage and current double closed loop set by the power control board and the unit control board, the adjustment is performed as follows: the voltage set value is the maximum value, and the voltage (feedback voltage) sampled by the voltage sensor is the minimum value, the difference between the two values ​​after subtraction by the voltage loop comparator, under the action of the voltage loop PI regulator, the output current loop set value is the maximum value, and after subtraction from the actual charging current (feedback current) by the current loop comparator, under the action of the current loop PI regulator, the PWM voltage is regulated by the driving board on the three-phase controllable front end, and the battery cell is charged in a constant current manner. During charging, as the battery cell voltage increases, the voltage of the series-connected battery cell gradually reaches the rated value; 3) In the constant voltage charging stage, near time t2, the voltage of the series-connected battery cell is close to the rated value, the voltage loop PI regulator gradually exits saturation, and under the action of the current loop PI regulator, the charging current gradually decreases, and the series-connected battery cell is fully charged or in a floating charge state.

[0013] ​​When the battery cell is nearly fully charged, the power control board starts the three-phase inverter bridge through the three-phase inverter bridge drive board. The three-phase inverter bridge outputs AC power with a rated frequency of 50Hz and a voltage of 380V and is in a standby state. The high-voltage frequency conversion system is in a standby state and exchanges information with the controllably charged three-phase emergency power supply and each of the controllably charged power units to prepare for normal lifting including emergency lifting.

[0014] In practice, the specifications and capacity of the battery cells in the controllable charging three-phase emergency power supply are selected according to the preset battery life and the power consumption of the main control cabinet and the mine hoist control system. The specifications and capacity of the battery cells in the controllable charging power unit and the number of battery cell series branches are selected in combination with the capacity of the hoisting motor and the nature of the load.

[0015] The charging current of the battery cell is controllable, and the discharging current of the battery cell depends on the load condition. The specification parameters of the battery cell can be pre-designed to ensure that the charging and discharging currents of the battery cell are within the allowable range of the battery cell during the charging and discharging process, which helps to extend the service life of the battery cell.

[0016] If the battery cell uses a supercapacitor, the capacitance of the supercapacitor is usually measured in farads. Before designing and selecting the battery cell, the capacitance of the supercapacitor is converted into Ah or Wh. Alternatively, if the supercapacitor has corresponding parameters marked with Ah or Wh, the design and selection method is the same as that of the battery cell.

[0017] The present invention proposes a high-voltage frequency conversion system for emergency lifting under a power outage in the whole mine, which is provided with a controllably charged three-phase emergency power supply and a controllably charged power unit, wherein the three-phase emergency power supply and the power unit are built with repeatedly chargeable and dischargeable batteries, and under normal power supply conditions, the high-voltage frequency conversion system cooperates with the mine hoist control system to automatically store electricity while performing normal lifting; under a power outage in the whole mine, the fully charged three-phase emergency power supply can not only provide control electricity for the high-voltage frequency conversion system, but also provide control electricity for the mine hoist control system, and similarly, the fully charged power unit can still provide power electricity for the mine hoisting motor; under a power outage in the whole mine, emergency lifting is performed through the high-voltage frequency conversion system of the present invention, which can not only safely evacuate the occupants trapped in the shaft to the ground, but also can last for a long time and perform multiple lifting-lowering cycles according to the design capacity, thereby meeting the needs of emergency rescue. Moreover, the battery cell has the characteristics of power storage and also has the smoothing and filtering functions of the capacitor, the use of the device is optimized, the charging and discharging current of the battery cell is within the allowable range, and it is helpful to extend the service life of the battery cell. The present invention has significant social and economic benefits while reducing equipment investment and operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A block diagram of the principle of a high-voltage frequency conversion system for emergency lifting during a mine power outage; Figure 2 This is a principle block diagram of the controllable charging power unit of the present invention; Figure 3 A schematic diagram of the charging process control of the controllable charging three-phase emergency power supply of the present invention; Figure 4 This is a schematic diagram of the charging process control of the controllable charging power unit of the present invention.

[0019] In the figure: 1. Controllable charging three-phase emergency power supply, 1.1. Battery cell, 1.2. DC current sensor, 1.3. DC voltage sensor, 1.4. DC switching power supply, 1.5. Power supply control board, 1.5.1. Voltage loop comparator, 1.5.2. Voltage loop PI regulator, 1.5.3. Current loop comparator, 1.5.4. Current loop PI regulator, 1.6. Three-phase controllable front end, 1.6.1. Three-phase controllable front end driver board, 1.7. Three-phase inverter bridge, 1.7.1. Three-phase inverter bridge driver board, 2. Controllable charging power unit, 2.1. Battery cell, 2.2. DC current sensor, 2.3. DC voltage sensor, 2.4 , DC switching power supply, 2.5, unit control board, 2.5.1, voltage loop comparator, 2.5.2, voltage loop PI regulator, 2.5.3, current loop comparator, 2.5.4, current loop PI regulator, 2.6, three-phase controllable front end, 2.6.1, three-phase controllable front end driver board, 2.7, single-phase inverter bridge, 2.7.1, single-phase inverter bridge driver board, 3, rectifier transformer, 3.1, primary winding, 3.2, secondary winding, 3.3, auxiliary winding, 4, high-voltage frequency conversion main control cabinet (including: K, conversion switch), 5.1, high-voltage contactor, 5.2, charging current limiting resistor, 6, mine hoist control system, 7, hoisting motor, u i , network power, u k , network controlled electricity. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described with reference to the accompanying drawings and specific embodiments: Combination Figure 1 and Figure 2, a high-voltage frequency conversion system for emergency lifting during a power outage in the entire mine, mainly composed of a controllable three-phase emergency power supply 1, three groups of controllable charging power units 2 connected in series at n levels, a rectifier transformer 3, a high-voltage frequency conversion main control cabinet 4, a high-voltage contactor 5.1 and a charging current limiting resistor 5.2. The secondary side of the rectifier transformer 3 is provided with 3*n windings to supply power to the power unit 2. In addition, the secondary side is also provided with a three-phase auxiliary winding. The output end (u1 is AC380V) of the auxiliary winding 3.3 of the rectifier transformer is connected to the input end of the controllable three-phase emergency power supply 1, and supplies power to the controllable three-phase emergency power supply 1, and at the same time charges the battery cell 1.1 therein online. The output end (u2 is AC380V) of the controllable three-phase emergency power supply 1 is connected to one power input end of the high-voltage frequency conversion main control cabinet 4, and the other power input end of the main control cabinet 4 is connected to the network control power (u k AC380V), therefore, the control power of the main control cabinet 4 is a dual-circuit input, and a conversion switch K (with two positions of "1-normal" and "0-emergency") is provided in the main control cabinet 4 to switch the dual-circuit control power. After the conversion switch is switched, it is connected to the mine hoist control system 6. The mine hoist control system 6 also has a dual-circuit control power. When the conversion switch K is at the "1-normal" position, the main control cabinet 4 and the mine hoist control system 6 are both controlled by the network power (u k AC380V) for control power; in addition, the main control cabinet 4 is connected to the mine hoist control system 6 through communication or point-to-point connection. The main control cabinet 4 receives the instructions of the mine hoist control system 6 and transmits the operating status and parameters of the high-voltage frequency conversion system of the present invention, including fault information, to the mine hoist control system 6. The O1 terminals of the three groups of the first-stage power units 2 are connected together to form a three-phase high-voltage power supply. o The output neutral point Q0, three groups of n-level controllable charging power units 2 are connected in series in the order of O2-O1, and the O2 ends of the three groups of n-level power units 2 are respectively connected to the three-phase input ends of the lifting motor 7, providing the lifting motor 7 with three-phase high-voltage power u with adjustable frequency and voltage. o ; The three-phase input terminals (a, b, c) of the three groups of n-level controllable charging power units 2 are respectively connected to the output terminals of the corresponding secondary windings 3.2 of the rectifier transformer to provide power electricity for the power units 2 and charge the battery cells 2.1 therein online. In addition, the three groups of n-level controllable charging power units 2 are connected to the main control cabinet 4 through optical fibers. The power units 2 receive instructions from the main control cabinet 4 and transmit the working status and parameters of the power units 2 including fault information to the main control cabinet 4. The three phases of the primary winding 3.1 of the rectifier transformer are respectively connected to one end of the three phases of the high-voltage contactor 5.1, and the other end of the high-voltage contactor 5.1 is respectively connected to the power electricity from the network (ui Three-phase connection for AC6kV or 10kV) The three phases of the high-voltage contactor 5.1 are respectively connected to the charging current limiting resistor 5.2, and the high-voltage frequency conversion system of the present invention receives the network power (u i AC6kV or 10kV) initially charges all the built-in cells 1.1 and 2.1 with limited current, and the coil of the high-voltage contactor 5.1 is connected to the control interface of the main control cabinet 4 (see Figure 1 In the direction J), the on-off of the high-voltage contactor 5.1 is controlled by the main control cabinet 4; under normal network power supply conditions, the network power (u i AC6kV or 10kV) through the high voltage frequency conversion system, the output frequency and voltage adjustable power u o Drive the lifting motor 7 to complete the normal lifting task, and charge all the batteries 1.1 and 2.1 built in the controllable charging three-phase emergency power supply 1 and the three groups of n-level series-connected controllable charging power units 2 online; in the event of a power outage in the entire mine, that is, u i =0,u k =0, the conversion switch K in the main control cabinet 4 is placed in the "0-emergency" position, the controllable and rechargeable three-phase emergency power supply 1 with fully charged battery cell 1.1 provides control power for the main control cabinet 4 and the mine hoist control system 6, and the three groups of n-level series-connected controllable and rechargeable power units 2 with fully charged battery cell 2.1 provide power power for the lifting motor 7, ensuring that the mine hoist can perform emergency lifting when the whole mine is out of power. Its endurance depends on the capacity of the battery cells 1.1 and 1.2, which can be designed and selected.

[0021] Figure 1 and Figure 3In the invention, the controllable charging three-phase emergency power supply 1 is mainly composed of a group of battery cells 1.1, a DC current sensor 1.2, a DC voltage sensor 1.3, a DC switching power supply 1.4, a power control board 1.5, a three-phase controllable front end 1.6 and its driving board 1.6.1, a three-phase inverter bridge 1.7 and its driving board 1.7.1 connected in series; a group of battery cells 1.1 connected in series with the DC current sensor 1.2 are connected in series, and then connected in parallel with the DC voltage sensor 1.3, the three-phase controllable front end 1.6, and the three-phase inverter bridge 1.7 to form DC1+ and DC1- poles, the input end of the DC switching power supply 1.4 is connected to DC1+ and DC1-, and the output end of the DC switching power supply 1.4 is connected to the power input end of the power control board 1.5, providing working power for the power control board 1.5, the three-phase controllable front end driving board 1.6.1, and the three-phase inverter bridge driving board 1.7.1. It can be seen that the internal working power supply of the controllable and rechargeable three-phase emergency power supply 1 only depends on a group of the battery cells 1.1 connected in series, and is not affected by the on-off status of the external power supply. Even if the input voltage u1, that is, u1=0, is fully charged under the action of a group of the battery cells 1.1 connected in series, the controllable and rechargeable three-phase emergency power supply 1 can also output a voltage of (u2 is AC380V / 50Hz), which meets the needs of providing control power for the emergency lifting of the high-voltage frequency conversion main control cabinet 4 and the mine hoist control system 6 in the case of a power outage in the whole mine; the secondary signal lines of the DC current sensor 1.2 and the DC voltage sensor 1.3 are connected to the power control board 1.5, which is used for the charge and discharge control of a group of the battery cells 1.1 connected in series, as well as the detection of current and voltage and the recording of historical parameters; the power control board 1.5 is connected to the main control cabinet 4 through an optical fiber, and the three-phase emergency power supply 1 receives instructions from the main control cabinet 4, and at the same time transmits the working status and parameters of the three-phase emergency power supply 1 including fault information to the main control cabinet 4.

[0022] Figure 2 and Figure 4In the controllable charging power unit 2, the controllable charging power unit 2 is mainly composed of at least one group of battery cells 2.1 connected in series and its DC current sensor 2.2, DC voltage sensor 2.3, DC switching power supply 2.4, unit control board 2.5, three-phase controllable front end 2.6 and its driving board 2.6.1, single-phase inverter bridge 2.7 and its driving board 2.7.1; at least one group of battery cells 2.1 connected in series and its DC current sensor 2.2 are connected in parallel with the DC voltage sensor 2.3, three-phase controllable front end 2.6, and single-phase inverter bridge 2.7 to form DC2+ and DC2- poles, the input end of the DC switching power supply 2.4 is connected to DC2+ and DC2-, and the output end of the DC switching power supply 2.4 is connected to the power input end of the unit control board 2.5, providing working power for the unit control board 2.5, the three-phase controllable front end driving board 2.6.1, and the single-phase inverter bridge driving board 2.7.1. It can be seen that the internal working power supply of the controllable charging power unit 2 only depends on at least one group of the battery cells 2.1 connected in series, and is not affected by the on / off status of the external power supply. Even if the input end of the power unit 2 is powered off, under the action of at least one group of the battery cells 2.1 connected in series, the power unit 2 can still output single-phase AC power with adjustable frequency and voltage according to the requirements of the main control cabinet 4. The three groups of controllable charging power units 2 connected in series at n levels can output three-phase high-voltage power with adjustable frequency and voltage. o , driving the lifting motor 7 to operate, meeting the needs of normal lifting and emergency lifting in the event of a power outage in the entire mine. The secondary signal lines of the DC current sensor 2.2 and the DC voltage sensor 2.3 are connected to the unit control board 2.5, which is used for charging and discharging control of the built-in battery cell 2.1, as well as current and voltage detection and historical parameter recording.

[0023] Figure 1 and Figure 2 In the embodiment, the battery cells 1.1 and 1.2 are repeatedly chargeable and dischargeable battery cells, or supercapacitor cells, which have a structure similar to that of commonly used electrolytic capacitors or non-polar capacitors and have capacitance characteristics. They are applied to the controllably chargeable three-phase emergency power supply 1 and power unit 2, and their main function is to store electricity, and they also have smoothing and filtering effects. The use of components is optimized, which can reduce costs, equipment size, and operation and maintenance costs.

[0024] Figure 1~Figure 4In the case of normal power supply, the charging process of the battery cells 1.1 and 2.1 is respectively controlled by the voltage and current double closed-loop PI (proportional integral) in the control boards 1.5 and 2.5. For this purpose, the control boards 1.5 and 2.5 are respectively provided with voltage loop comparators 1.5.1 and 2.5.1, voltage loop PI regulators 1.5.2 and 2.5.2, current loop comparators 1.5.3 and 2.5.3, current loop PI regulators 1.5.4 and 2.5.4, etc. The adjustment signals output by the double closed-loops are respectively acted on the three-phase controllable front ends 1.6 and 2.6 through the corresponding drive boards 1.6.1 and 2.6.1 to perform PWM voltage regulation, and respectively control the charging of the built-in battery cells 1.1 and 1.2. The charging process is divided into three stages: current limiting charging, constant current charging, and constant voltage charging, which are described as follows: 1) In the current limiting charging stage, at time t0, the high-voltage frequency conversion system receives the network power (u i is 6kV or 10kV), the high voltage contactor 5.1 is in an open circuit state, u i After the voltage division of the charging current limiting resistor 5.2, the voltage applied to the primary winding 3.1 of the rectifier transformer is a smaller value, and the three-phase rectifier bridge rectifier composed of the auxiliary winding 3.3 of the rectifier transformer, the secondary winding 3.2, and the diodes connected in parallel in the power devices of the three-phase controllable front end 1.6 and 2.6 is rectified. Assuming that the DC 1+ 、DC 1- The voltage across the two ends is U d10 , D.C. 2+ 、DC 2- The voltage across the two ends is U d20 , greater than the total residual voltage U of the cells 1.1 and 2.1 connected in series d11 , U d21 When (U d10 >U d11 , U d20 >U d21 ), the battery cells 1.1 and 2.1 connected in series are charged with current limiting. If the current is less than the total residual voltage U of the battery cells 1.1 and 2.1 connected in series, d11 , U d21 When (U d10 d11 , U d20 d21 ), it directly enters the constant current charging stage of controllable charging; the design requirement is that the input voltage is U d10 and U d20 ​​, the DC switching power supplies 1.4 and 2.4 can work normally and provide working power for the control boards 1.5 and 2.5 and the drive boards 1.6.1 and 2.6.1. 2) During the constant current charging phase, at time t1, the main control cabinet 4 instructs the high-voltage contactor 5.1 to close, short-circuiting the parallel charging current limiting resistor 5.2, and the network power (u i 6kV or 10kV) is directly applied to the primary winding 3.1 of the rectifier transformer 3, and the auxiliary winding 3.3 and the secondary winding 3.2 of the rectifier transformer both output rated voltage; in the voltage and current double closed loop set by the power control board 1.5 and the unit control board 2.5, the adjustment is performed as follows: the voltage set value U 1g , U 2g is the maximum value, and the voltage (feedback voltage) sampled by the voltage sensors 1.3 and 2.3 is U 1d , U 2d is a small value, and the difference U after subtracting the two values ​​by the voltage loop comparator 1.5.1 and 2.5.1 is 1g -U 1d , U 2g -U 2d , under the action of voltage loop PI regulator 1.5.2, 2.5.2, the output current loop given value I 1g ,I 2g The maximum value is subtracted from the actual charging current (feedback current) i1 and (i2+i3) by the current loop comparator 1.5.3 and 2.5.3. Under the action of the current loop PI regulator 1.5.4 and 2.5.4, the driving board 1.6.1 and 2.6.1 act on the three-phase controllable front end 1.6 and 2.6 to perform PWM voltage regulation, and the battery cells 1.1 and 2.1 are charged in a constant current manner. During charging, as the voltage of the battery cells 1.1 and 2.1 increases, the voltage U d1 , U d2 Gradually reaches the rated value; 3) Constant voltage charging stage, close to time t2, the voltage U of the battery cells 1.1 and 2.1 connected in series d1 , U d2 Approaching the rated value, the voltage loop PI regulators 1.5.2 and 2.5.2 gradually exit saturation, and under the action of the current loop PI regulators 1.5.4 and 2.5.4, the charging currents i1 and (i2+i3) gradually decrease, and the battery cells 1.1 and 2.1 connected in series are fully charged or in a floating charge state.

[0025] Figure 1In the embodiment, when the battery cell 1.1 is nearly fully charged, the power control board 1.5 starts the three-phase inverter bridge 1.7 through the three-phase inverter bridge drive board 1.7.1, and the three-phase inverter bridge 1.7 outputs AC power with a rated frequency of 50Hz and a voltage of 380V and is in a standby state. The high-voltage frequency conversion system is in a standby state, and exchanges information with the controllably charged three-phase emergency power supply 1 and each of the controllably charged power units 2 to prepare for normal lifting including emergency lifting.

[0026] In use, see Figure 1 and Figure 2 Assuming that the whole mine is out of power, the emergency lifting time of the mine hoist is preset to 2h (hours). According to incomplete statistics, the power consumption of the main control cabinet and the mine hoist control system is about 25kW / 380V. The rated input and output voltage of the controllable charging three-phase emergency power supply (u1 and u2 are both AC380V), of which DC 1+ 、DC 1- Rated voltage across both ends (U d1 Designed according to DC630V), the battery capacity is selected as 3.6V / 100Ah, and a group of 175 battery cells 1.1 are required to be connected in series. In this way, the controllable and rechargeable three-phase emergency power supply 1 has a capacity of 63kWh. It is estimated that the emergency endurance is about 2.5h, which meets the requirement of 2h endurance; assuming that the power of the lifting motor 7 in the auxiliary shaft is 630kW / 6kV and the rated current is about 77A, the input (a, b, c) rated voltage of the controllable and rechargeable power unit 2 is designed and selected according to three-phase AC500V, and the output (O1, O2) rated voltage is designed and selected according to single-phase AC580V, among which DC 2+ 、DC 2- Rated voltage across both ends (U d2 Designed according to DC828V), the battery cell is also 3.6V / 100Ah, each controllable charging power unit 2 requires a group of 230 battery cells 2.1 connected in series, and the high-voltage frequency conversion system of the present invention composed of 3*6 (three-phase, 6 levels in series per phase) power units 2 drives the lifting motor 7. In this way, each power unit has a capacity of 82.8kWh, and the high-voltage frequency conversion system has a capacity of 1490.4kWh. It is estimated that the emergency lifting endurance is about 2.4h, which also meets the requirement of 2h endurance. It is worth mentioning that, unlike the three-phase rectifier bridge, the three-phase controllable front end 1.6, 2.6 under PWM modulation, the input rated voltage of the controllable charging three-phase emergency power supply 1 is AC380V, of which DC 1+ 、DC 1- Voltage across the terminals U d1 Adjustable, U d1The rated voltage of the controllable charging power unit 2 can be increased to and stabilized at DC630V according to the setting pump; the input rated voltage of the controllable charging power unit 2 is AC500V, where DC 2+ 、DC 2- Voltage across the terminals U d2 Adjustable, U d2 The rated voltage can be increased to and stabilized at DC828V according to the setting pump.

[0027] If the power of the lifting motor 7 in the auxiliary shaft is 1250kW / 6kV, the rated current is about 155A, and the selected battery cell 2.1 is still 3.6V / 100Ah, then each controllable charging power unit 2 needs two groups of 230 battery cells 2.1 connected in series to meet the same endurance requirement of 2h.

[0028] In the above example, the charging current of the battery cells 1.1 and 2.1 are controllable, and the maximum discharge current of the battery cells depends on the starting current value of the lifting motor 7 in the acceleration stage. Under the drive of the high-voltage frequency conversion system, the starting current is usually less than 1.3 times the rated current of the lifting motor, and the discharge rate of the battery cells 1.1 and 2.1 is usually not less than 2. The specifications of the battery cells 1.1 and 2.1 are 3.6V / 100Ah, that is, the allowable discharge current does not exceed 200A. This ensures that the charging and discharging currents of the battery cells are within the allowable range of the battery cells during the charging and discharging process, which helps to extend the service life of the battery cells.

[0029] If the battery cells 1.1 and 2.1 use supercapacitors, the capacitance of the supercapacitor is usually measured in farads. Before designing and selecting the battery cells 1.1 and 2.1, the capacitance of the supercapacitor is converted into Ah or Wh. Alternatively, the supercapacitor has corresponding parameters marked in Ah or Wh. For example, the parameters of a certain brand of supercapacitor are marked as: 900F (80Ah) / 3.6V. The subsequent design and selection process is the same as the above embodiment.

[0030] Finally, it should be noted that the above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent transformation based on the technical solution of the present invention belongs to the protection scope of the present invention.

Claims

1. A high-voltage frequency conversion system for emergency lifting during a mine power outage, characterized in that: The high-voltage frequency conversion system is provided with a controllable and rechargeable three-phase emergency power supply and three groups of controllable and rechargeable power units connected in series at n levels; the controllable and rechargeable three-phase emergency power supply and the power unit are provided with battery cells; a three-phase auxiliary winding is provided on the secondary side of the rectifier transformer corresponding to the controllable and rechargeable three-phase emergency power supply; the secondary side of the rectifier transformer is also provided with 3*n windings for supplying power to the power unit; the output end u1 of the three-phase auxiliary winding is connected to the input end of the controllable and rechargeable three-phase emergency power supply to supply power to the controllable and rechargeable three-phase emergency power supply and charge the battery cells therein online at the same time; the output end u2 of the controllable and rechargeable three-phase emergency power supply is connected to one power input end of the high-voltage frequency conversion main control cabinet, and the other power input end of the high-voltage frequency conversion main control cabinet is connected to the network control circuit u1. k The two control circuits are connected to form a double-circuit input control power of the high-voltage frequency conversion main control cabinet; a conversion switch is provided in the high-voltage frequency conversion main control cabinet for switching the double-circuit control power, which is connected to the mine hoist control system after switching by the conversion switch, so that the mine hoist control system has a double-circuit control power; the conversion switch has two positions, "normal" and "emergency"; when the conversion switch is in the "normal" position, the main control cabinet and the mine hoist control system are both controlled by the network control power u k In addition, the main control cabinet is connected to the mine hoist control system through communication or point-to-point connection. The main control cabinet receives the command of the mine hoist control system and transmits the operating status and parameters of the high-voltage frequency conversion system including fault information to the mine hoist control system. The O1 terminals of the three groups of first-stage power units are connected together to form a three-phase high-voltage power supply. o The output neutral point Q0, three groups of n-level controllable charging power units are connected in series in the order of O2-O1, and the O2 ends of the three groups of n-level power units are connected to the three-phase input ends of the lifting motor respectively, providing the lifting motor with three-phase high-voltage power u with adjustable frequency and voltage o ; The three-phase input ends of the three groups of n-level controllable charging power units are respectively connected to the output ends of the corresponding secondary windings of the rectifier transformer to provide power electricity for the power units and charge the batteries therein online. In addition, the three groups of n-level controllable charging power units are connected to the main control cabinet through optical fibers. The power units receive instructions from the main control cabinet and transmit the working status and parameters of the power units, including fault information, to the main control cabinet; the three phases of the primary winding of the rectifier transformer are respectively connected to one end of the three phases of the high-voltage contactor, and the other end of the high-voltage contactor is respectively connected to the power supply u from the network. i The three phases of the high-voltage contactor are connected in parallel with a charging current limiting resistor, and the high-voltage frequency conversion system of the present invention receives network power u i Initially, all built-in battery cells are charged with current limiting. The coil of the high-voltage contactor is connected to the control interface of the main control cabinet, and the on and off of the high-voltage contactor is controlled by the main control cabinet. When the network power supply is normal, the network power supply u i Through the high-voltage frequency conversion system, the output frequency and voltage are adjustable. o Drive the lifting motor to complete the normal lifting task, charge all the batteries built into the three-phase emergency power supply of the controllable charge and the three groups of n-level series-connected controllable charge power units online; in the event of a power outage in the entire mine, that is, u i =0,u k =0, the switch in the main control cabinet is placed in the "emergency" position, the three-phase emergency power supply with fully charged cells provides control power for the main control cabinet and the mine hoist control system, and the three groups of n-level series-connected controllable power units with fully charged cells provide power for the hoisting motor. o , ensuring that the mine hoist can carry out emergency lifting in the case of a power outage in the entire mine. Its endurance depends on the capacity of the battery cell and can be designed and selected; The controllable and rechargeable three-phase emergency power supply is mainly composed of a group of battery cells connected in series, a DC current sensor, a DC voltage sensor, a DC switching power supply, a power control board, a three-phase controllable front end and its driving board, a three-phase inverter bridge and its driving board; a group of the battery cells connected in series are connected in series with the DC current sensor, and then connected in parallel with the DC voltage sensor, the three-phase controllable front end and the three-phase inverter bridge to form DC1+ and DC1- poles, the input end of the DC switching power supply is connected to DC1+ and DC1-, and the output end of the DC switching power supply is connected to the power input end of the power control board to provide working power for the power control board, the three-phase controllable front end driving board and the three-phase inverter bridge driving board; it can be seen that the internal working power supply of the controllable and rechargeable three-phase emergency power supply only depends on a group of the battery cells connected in series, and is not affected by external The controllable charging three-phase emergency power supply can output voltage u2 and frequency 50Hz under the action of a group of the battery cells connected in series and fully charged, so as to meet the demand of providing control power for emergency lifting of the high-voltage frequency conversion main control cabinet and the mine hoist control system in the case of a power outage in the whole mine; the secondary signal lines of the DC current sensor and the DC voltage sensor are connected to the power control board, which is used for charging and discharging control of a group of the battery cells connected in series, current and voltage detection, and historical parameter recording; the power control board is connected to the main control cabinet through optical fiber, and the three-phase emergency power supply receives instructions from the main control cabinet, and transmits the working status and parameters of the three-phase emergency power supply including fault information to the main control cabinet.

2. A high-voltage frequency conversion system for emergency lifting during a mine power outage as claimed in claim 1, characterized in that: The controllable charging power unit is mainly composed of at least one group of battery cells connected in series and their series-connected DC current sensors, DC voltage sensors, DC switching power supplies, unit control boards, three-phase controllable front ends and their drive boards, single-phase inverter bridges and their drive boards; at least one group of battery cells connected in series and their series-connected DC current sensors are connected in parallel with the DC voltage sensors, three-phase controllable front ends and single-phase inverter bridges to form DC2+ and DC2- poles, the input end of the DC switching power supply is connected to DC2+ and DC2-, and the output end of the DC switching power supply is connected to the power input end of the unit control board. The controllable charging power unit is connected to provide working power for the unit control board, the three-phase controllable front-end drive board, and the single-phase inverter bridge drive board; it can be seen that the internal working power supply of the controllable charging power unit only depends on at least one group of the battery cells connected in series, and is not affected by the on-off status of the external power supply. Even if the input end of the power unit is powered off, under the action of at least one group of the battery cells connected in series and fully charged, the power unit can still output single-phase AC power with adjustable frequency and voltage according to the requirements of the main control cabinet. The three groups of controllable charging power units connected in series at n levels can output three-phase high-voltage power with adjustable frequency and voltage. o , driving the lifting motor to operate, meeting the needs of normal lifting and emergency lifting in the event of a power outage in the entire mine; the secondary signal lines of the DC current sensor and DC voltage sensor are connected to the unit control board, which is used for the built-in battery cell charging and discharging control, current and voltage detection, and historical parameter recording.

3. A high-voltage frequency conversion system for emergency lifting during a mine power outage as claimed in claim 1 or 2, characterized in that: The battery cell is a repeatedly chargeable and dischargeable battery cell or a super capacitor cell.

4. A high-voltage frequency conversion system for emergency lifting during a mine power outage as claimed in claim 1, 2 or 3, characterized in that: Under normal power supply conditions, the charging process of the battery cell is respectively controlled by the voltage and current dual closed-loop PI proportional integral control in the control board. To this end, the control board is respectively provided with a voltage loop comparator, a voltage loop PI regulator, a current loop comparator, and a current loop PI regulator. The adjustment signals output by the dual closed loops act on the three-phase controllable front end through the corresponding driving board to perform PWM voltage regulation, and the charging of the built-in battery cells is respectively controlled. The charging process is divided into three stages: current limiting charging, constant current charging, and constant voltage charging.

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