A high-power battery power supply system for a mobile rail flash butt welding machine

Abstract

The application belongs to the field of steel rail flash welding, and particularly relates to a high-power battery power supply system of a mobile steel rail flash welding machine, a house body system, a lithium iron phosphate battery system, a super capacitor system, a high-power bidirectional DC / 3AC converter, a bidirectional DC / DC converter, a transformer and a power distribution cabinet; the lithium iron phosphate battery system is connected with the bidirectional DC / DC converter, the super capacitor system is connected with the bidirectional DC / DC converter and the high-power bidirectional DC / 3AC converter, one end of the bidirectional DC / DC converter is connected with the high-power bidirectional DC / 3AC converter, and the high-power bidirectional DC / 3AC converter is connected with the power distribution cabinet through the transformer. The application adopts a mixed power supply mode of lithium iron phosphate batteries and super capacitors to supply power to the welding machine, and solves the problem of increased harmful pollutants caused by traditional diesel generator sets. In the construction of long underground tunnels such as subways, almost zero pollutant emission is beneficial to the physical and mental health of the construction operators, and the green environmental protection purpose is achieved.

Description

Technical Field

[0001] This application belongs to the field of rail flash welding, specifically relating to a high-power battery power supply system for a mobile rail flash welding machine. Background Technology

[0002] Currently, mobile flash rail welding machines are crucial equipment for welding high-speed, heavy-load seamless railway tracks and urban rail transit tracks in my country. Traditional mobile flash rail welding machines mostly use diesel generator sets for power. Because flash welding machines generally use two-phase power, using diesel generator sets can cause three-phase load imbalance, leading to overload operation, severe black smoke emissions, carbon buildup, increased noise, and serious environmental pollution. Whether in high-altitude areas or enclosed environments, especially during long subway tunnel construction, using traditional mobile flash rail welding machines is detrimental to worker operations. Therefore, in response to national green environmental protection requirements, to optimize the rail welding working environment, reduce the risk of occupational diseases, and significantly reduce particulate matter and harmful gases in diesel generator set exhaust emissions, a high-power battery power supply system for mobile flash rail welding machines has been developed to replace traditional diesel generator sets.

[0003] CN114583812A discloses a method for supplying DC power to a welding machine by charging a supercapacitor with a fuel cell and switching between two sets of supercapacitors to provide alternating power. However, this method requires the welding machine to be a DC welding machine, or an additional inverter system to convert the DC power to AC power. This makes the control of the welding machine more complex and increases costs. Summary of the Invention

[0004] This application addresses the aforementioned defects and problems in the prior art by providing a high-power battery power supply system for a mobile rail flash welding machine that uses a hybrid power supply of lithium iron phosphate batteries and supercapacitors.

[0005] To achieve the above effects, the technical solution of this application is as follows: A high-power battery power supply system for a mobile rail flash welding machine includes a housing system. The housing system houses a lithium iron phosphate battery system, a supercapacitor system, a high-power bidirectional DC / 3AC converter, a bidirectional DC / DC converter, a transformer, and a distribution cabinet. The lithium iron phosphate battery system is connected to the bidirectional DC / DC converter, the supercapacitor system is connected to both the bidirectional DC / DC converter and the high-power bidirectional DC / 3AC converter, one end of the bidirectional DC / DC converter is connected to the high-power bidirectional DC / 3AC converter, and the high-power bidirectional DC / 3AC converter is connected to the distribution cabinet via the transformer.

[0006] Furthermore, the housing system is a mobile container, which also includes a built-in lighting system, fire-fighting equipment, and temperature and humidity sensors. The decorative material of the mobile container is a fire-retardant and environmentally friendly material.

[0007] Furthermore, the power distribution cabinet is connected to an external power source and to a rail welding machine.

[0008] Furthermore, the transformer is a three-phase isolation transformer.

[0009] Furthermore, the three-phase isolation transformer isolates and filters the three-phase power supplied by the bidirectional DC / 3AC converter, forming a three-phase 400V / 50Hz sinusoidal AC power, which is then supplied to the mobile flash rail welding machine via the distribution cabinet.

[0010] Furthermore, the lithium iron phosphate battery system has a capacity of 422.87 kWh, an operating voltage of 480-700 V, and a peak discharge current of 1000 A.

[0011] Furthermore, the supercapacitor has a system charge of ≥0.6kWh and an operating voltage range of 309~618V.

[0012] Furthermore, the rated input power of the high-power bidirectional DC / 3AC converter is ≥500kVA, the rated input voltage is DC650V-950V, the rated output power is ≥500kVA, and the rated output voltage is 3AC400V / 50Hz.

[0013] Furthermore, the bidirectional DC / DC converter has a rated input power ≥100kW, a rated input voltage of DC650V-950V, a rated input current ≥DC 160A, a rated output power ≥100kW, a rated output voltage of DC309~618V, and a rated output current ≥DC 160A.

[0014] Furthermore, the power distribution cabinet has a built-in centralized controller.

[0015] The beneficial effects of this application are as follows: 1. This application employs a hybrid power supply method combining lithium iron phosphate battery packs and supercapacitors to power the welding machine, solving the problem of increased harmful pollutants caused by traditional diesel generator sets. During the construction of long underground tunnels such as subways, the near-zero pollutant emissions are beneficial to the physical and mental health of construction workers, achieving the goal of green environmental protection.

[0016] 2. It solves the problems of reduced power, increased fuel consumption, and increased heat load of diesel generator sets due to thin air and low oxygen content during construction in high-altitude areas. The use of high-power batteries ensures the stability and reliability of welding.

[0017] 3. During nighttime when electricity prices are low, the energy storage battery is charged to the set value via a charger; during the day, the energy storage battery is powered by a DC / DC module to achieve peak shaving and valley filling of electricity prices, thereby improving the user's economic benefits.

[0018] 4. High-power bidirectional DC / 3AC converters and bidirectional DC / DC converters are used to control the charging and discharging rhythm of the lithium iron phosphate battery system and the supercapacitor system, preventing overcharging and over-discharging of the lithium iron phosphate battery system and the supercapacitor system.

[0019] 5. The power supply mode provided in this application is a hybrid power supply of lithium iron phosphate battery and supercapacitor, with the supercapacitor directly connected to the DC bus. The direct connection of the supercapacitor to the bus provides extremely fast power response, offering better peak shaving and valley filling for the instantaneous high current demand during welding, and better protecting the battery. Simultaneously, this application employs a three-phase isolation transformer, completely isolating the primary (inverter side) and secondary (welding machine load side) circuits electrically, effectively preventing high voltage surges from the DC side (battery, supercapacitor) into the AC side due to faults. This greatly ensures the safety of the welding equipment and operators, making it particularly suitable for use in damp, complex environments such as tunnels or construction sites. Furthermore, the distribution cabinet has a built-in centralized controller that monitors battery status and inverter output, and dynamically coordinates the output of the battery and supercapacitor based on the welding current (e.g., >800A), maximizing system efficiency, protecting battery life, and ensuring voltage stability during the welding process. Attached Figure Description

[0020] Figure 1 A schematic diagram of the high-power battery power supply system for a mobile rail flash welding machine.

[0021] Figure 2 This is a topology diagram of a bidirectional DC / 3AC converter.

[0022] Figure 3 This is a topology diagram of a bidirectional DC-DC converter.

[0023] Figure 4 This is the topology diagram of the power distribution cabinet mode switching circuit.

[0024] In the attached diagram: 1-Building system, 2-Lithium iron phosphate battery system, 3-Supercapacitor system, 4-High-power bidirectional DC / 3AC converter, 5-Bidirectional DC / DC converter, 6-Transformer, 7-Distribution cabinet, 8-External power supply, 9-Rail welding machine, 10-Central controller. Detailed Implementation

[0025] Example 1 like Figure 1As shown, a high-power battery power supply system for a mobile rail flash welding machine includes a housing system 1. The housing system 1 houses a lithium iron phosphate battery system 2, a supercapacitor system 3, a high-power bidirectional DC / 3AC converter 4, a bidirectional DC / DC converter 5, a transformer 6, and a distribution cabinet 7. The lithium iron phosphate battery system 2 is connected to the bidirectional DC / DC converter 5, providing the total energy source for the power supply system and handling the current output during the welding process. The supercapacitor system 3 is connected to the bidirectional DC / DC converter 5 and the high-power bidirectional DC / 3AC converter 4, supplementing the lithium battery's discharge capacity. It provides instantaneous high-power and high-rate discharge current support for the rail welding machine 9, rapidly increasing the system's discharge capacity and protecting the lithium iron phosphate battery pack. One end of the bidirectional DC / DC converter is connected to the high-power bidirectional DC / 3AC converter 4, automatically replenishing energy to the DC bus, regulating the DC bus voltage, and saving the time required for separate supercapacitor charging. The high-power bidirectional DC / 3AC converter 4 is connected to the distribution cabinet 7 via the transformer 6. The bidirectional DC / 3AC converter is responsible for converting DC voltage into three-phase 400V AC power to supply the downstream load, and then outputting three-phase four-wire 400V AC power through the three-phase isolation transformer 6 to supply power to the main circuit and auxiliary system of the welding machine. On the other hand, the bidirectional DC / 3AC converter outputs three-phase AC 380V through external power supply (grid or diesel generator set), which can be used to charge lithium iron phosphate battery packs.

[0026] The housing system 1 is a mobile container, which also includes a built-in lighting system, fire-fighting equipment, and temperature and humidity sensors. The exterior materials of the mobile container are fire-retardant and environmentally friendly. The mobile container is suitable for harsh working conditions such as railway rail welding, can be transported as a whole, and has functions such as fireproofing, sandproofing, shockproofing, waterproofing, and heat insulation.

[0027] The power distribution cabinet 7 is connected to the external power supply 8, and the power distribution cabinet 7 is also connected to the rail welding machine 9.

[0028] Transformer 6 is a three-phase isolation transformer. The three-phase isolation transformer 6 isolates and filters the three-phase power supplied by the bidirectional DC / 3AC converter to form a three-phase 400V / 50Hz sinusoidal AC power, which is then supplied to the mobile flash rail welding machine 9 through the distribution cabinet 7.

[0029] The lithium iron phosphate battery system 2 has a capacity of 422.87 kWh, which is enough to power 40 welding heads per day. To meet welding requirements, the operating voltage is 480-700V and the peak discharge current is 1000A.

[0030] The supercapacitor has a system capacity of ≥0.6kWh and an operating voltage range of 309~618V.

[0031] The high-power bidirectional DC / 3AC converter 4 has a rated input power ≥500kVA, a rated input voltage of DC 650V-950V, a rated output power ≥500kVA, and a rated output voltage of 3AC 400V / 50Hz (three-phase four-wire system).

[0032] The bidirectional DC / DC converter has a rated input power ≥100kW, a rated input voltage of DC650V-950V, a rated input current ≥DC 160A, a rated output power ≥100kW, a rated output voltage of DC309~618V, and a rated output current ≥DC160A.

[0033] The distribution cabinet 7 has a built-in centralized controller 10.

[0034] Example 2 The mobile rail flash welding machine's high-power battery power supply system includes a housing system 1, a lithium iron phosphate battery system 2, a supercapacitor system 3, a high-power bidirectional DC / 3AC converter 4, a bidirectional DC / DC converter 5, a transformer 6, and a distribution cabinet 7. The lithium iron phosphate battery system 2 is connected to the bidirectional DC / DC converter 5 and the high-power bidirectional DC / 3AC converter 4; the supercapacitor is connected to the DC / DC converter; the high-power bidirectional DC / 3AC converter 4 is connected to the transformer 6; the transformer 6 is connected to the distribution cabinet 7; the input terminal of the distribution cabinet 7 is connected to an external power supply 8, and the output terminal is connected to the welding machine.

[0035] The mobile rail flash welding machine's high-power battery power supply system has two working modes: external power supply mode and charging mode.

[0036] like Figure 1As shown, during welding, the external operation switch on the distribution cabinet 7 is selected to "external power supply mode". The high-power bidirectional DC / 3AC converter 4 is powered by a combination of lithium iron phosphate batteries and supercapacitors within the system. The three-phase AC output from the converter is isolated and filtered by transformer 6 to form three-phase 400V / 50Hz sinusoidal AC power, which is then supplied to the mobile flash welding machine 9 via distribution cabinet 7. Based on the requirements (power needed to complete 40 welding heads per day), the lithium iron phosphate battery capacity is designed to be no less than 400kWh. The supercapacitor smooths out the peak and valley of the inrush current, providing the power and energy required by the mobile flash welding machine during welding. The high-power bidirectional DC / 3AC converter 4 operates in external power supply mode during welding, converting the DC power supplied by the lithium iron phosphate battery into three-phase AC power. The converter contains DC and AC filter units. The DC filter limits the voltage and current ripple during the charging and discharging of the current limiter; the AC filter unit limits the harmonics of the converter. Charge the lithium iron phosphate battery at night when electricity prices are lower. Select "charging mode" on distribution cabinet 7 and connect the external power source 8 (grid or diesel generator set) to distribution cabinet 7. The three-phase AC power is transformed by distribution cabinet 7 and transformer 6, and then converted into DC power by high-power bidirectional DC / 3AC converter 4 to charge the lithium iron phosphate battery.

[0037] The distribution cabinet 7 has a built-in centralized controller 10, which can monitor the battery status of the lithium iron phosphate batteries, including real-time monitoring of the voltage of individual battery cells, the total system voltage, the current and temperature during battery pack charging and discharging, the insulation resistance of the power battery to the enclosure, accurate calculation of the remaining charge of the power battery, fault diagnosis, and corresponding measures; it also detects the inverter output current of the high-power bidirectional DC / 3AC converter 4 and the welding duration. In accordance with the control strategy, when the external power supply mode is selected, if the inverter output current detected by the high-power bidirectional DC / 3AC converter 4 is greater than 800A, it notifies the bidirectional DC / DC converter 5 to start the supercapacitor and lithium iron phosphate batteries to output a larger current and power; when the detected inverter output current is less than 600A, it notifies the bidirectional DC / DC converter 5 to reduce the system output of the supercapacitor and lithium iron phosphate batteries, stabilizing the intermediate DC voltage and ensuring the stability of the high-power bidirectional DC / 3AC converter 4 during the rail welding process.

[0038] like Figure 2The diagram shows the topology of a bidirectional DC-3AC converter. When implementing DC-3AC conversion, it operates in inverter mode. DC power supply V2 provides energy, which is connected to the circuit via contactor KM6. The current flows through switching transistors VT1, VT2, VT3, VT4, VT5, and VT6, forming a three-phase full-bridge inverter circuit. This circuit is controlled by PWM waves to alternately conduct, converting the DC power into a high-frequency AC square wave. Inductors L1 and L2, along with capacitors C1, C2, and C3, form an LC filter network to smooth high-frequency harmonics. Contactors KM3 and KM4 control the output path, and after filtering, the 3AC output is from terminals A3, B3, and C3. When implementing 3AC-DC conversion, it is in rectification mode. Three-phase AC power is input from the A3, B3, and C3 sides. Contactors KM3 and KM5 are closed, and KM6 is open. A three-phase bridge fully controlled rectifier circuit is formed by the flow through the switching transistors VT1, VT2, VT3, VT4, VT5, and VT6, which converts the three-phase AC power into pulsating DC power. Inductor L2 is a smoothing reactor to suppress current surges. Capacitors C1 and C2 further smooth the output voltage and store energy to stabilize the DC component. After rectification and filtering, the current flows out from V1.

[0039] like Figure 3 The diagram shows a bidirectional DC-DC converter topology. KM21, KM22, KM23, and KM24 work in conjunction with the MOSFETs and inductors to form the DC-DC converter. By switching KM21-KM24 on and off, the MOSFETs within the converter form different circuits to complete the Buck and Boost circuits. When V1 is input, KM21 and KM24 are turned on, working with the MOSFETs to complete the Buck circuit, and the current flows through F21 before being output. When current flows through F21 as input, KM22 and KM23 are turned on, working with the MOSFETs to complete the Boost circuit, and the current flows out from the V1 side.

[0040] like Figure 4 The diagram shown is the topology of the mode switching circuit for distribution cabinet 7. When KM1 is activated, it controls... Figure 2 , Figure 3 The corresponding switches form a corresponding circuit. The system uses two lithium iron phosphate batteries and three supercapacitors to power four high-power bidirectional DC / 3AC converters. The converters output three-phase AC power, which is then filtered and isolated by a six-transformer to form three-phase 400V / 50Hz sinusoidal AC power. Finally, this power is supplied to the mobile flash rail welding machine 9 via the distribution cabinet 7. When KM2 is activated, the control... Figure 2 , Figure 3 The corresponding switches form the corresponding circuits. After the external power source 8 (diesel engine, power grid, etc.) starts, the three-phase AC power generated is converted into DC power by the four high-power bidirectional DC / 3AC converters 4 after passing through the distribution cabinet 7 to charge the two lithium iron phosphate batteries.

Claims

1. A high-power battery power supply system for a mobile rail flash welding machine, characterized in that: The system includes a housing system (1), which is equipped with a lithium iron phosphate battery system (2), a supercapacitor system (3), a high-power bidirectional DC / 3AC converter (4), a bidirectional DC / DC converter (5), a transformer (6), and a distribution cabinet (7). The lithium iron phosphate battery system (2) is connected to the bidirectional DC / DC converter (5), the supercapacitor system (3) is connected to the bidirectional DC / DC converter (5) and the high-power bidirectional DC / 3AC converter (4), one end of the bidirectional DC / DC converter is connected to the high-power bidirectional DC / 3AC converter (4), and the high-power bidirectional DC / 3AC converter (4) is connected to the distribution cabinet (7) through the transformer (6).

2. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The housing system (1) is a mobile container. The mobile container is also equipped with a built-in lighting system, fire-fighting equipment and temperature and humidity sensor. The decorative material of the mobile container is a fire-resistant, flame-retardant and environmentally friendly material.

3. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The power distribution cabinet (7) is connected to an external power source (8) and the power distribution cabinet (7) is connected to a rail welding machine (9).

4. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The transformer (6) is a three-phase isolation transformer (6).

5. The high-power battery power supply system for a mobile rail flash welding machine according to claim 4, characterized in that: The three-phase isolation transformer (6) isolates and filters the three-phase power supplied by the bidirectional DC / 3AC converter to form a three-phase 400V / 50Hz sinusoidal AC power, which is then supplied to the mobile flash rail welding machine (9) through the distribution cabinet (7).

6. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The lithium iron phosphate battery system (2) has a capacity of 422.87 kWh, an operating voltage of 480-700 V, and a peak discharge current of 1000 A.

7. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The supercapacitor has a system capacity of ≥0.6kWh and an operating voltage range of 309~618V.

8. The high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The high-power bidirectional DC / 3AC converter (4) has a rated input power ≥ 500kVA, a rated input voltage of DC 650V-950V, a rated output power ≥ 500kVA, and a rated output voltage of 3AC 400V / 50Hz.

9. A high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The bidirectional DC / DC converter (5) has a rated input power ≥100kW, a rated input voltage of DC650V-950V, a rated input current ≥DC 160A, a rated output power ≥100kW, a rated output voltage of DC309~618V, and a rated output current ≥DC160A.

10. A high-power battery power supply system for a mobile rail flash welding machine according to claim 1, characterized in that: The power distribution cabinet (7) has a built-in centralized controller (10).

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