A DC power supply system suitable for vehicle base and control method thereof

Abstract

The present invention discloses a DC power supply system suitable for a vehicle base and a control method thereof, which belongs to the field of power supply technology and includes: at least one DC bus, a step-down substation, a photovoltaic system, an energy feedback module, an electric equipment module, a monitoring host, a communication manager, an on-site control panel, and a battery charging and discharging module. The step-down substation, the photovoltaic system, the energy feedback module, and the battery charging and discharging module are all electrically connected to the DC bus. The lighting, fan and other equipment that can be powered by DC are combined with all systems and equipment that can provide electric energy. The battery charging and discharging module and the energy feedback module can absorb electric energy and release excess and useless electric energy. The photovoltaic system can continuously provide clean energy. The step-down substation, as a part supporting the stability of the system, can obtain electric energy from the power grid when the local electric energy is insufficient, and return electric energy to the medium-voltage power grid when the local electric energy is excessive, so as to realize the utilization of renewable energy.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a direct current power supply system suitable for a vehicle base and a control method thereof. Background Art

[0002] In the power supply system of the subway vehicle base plant, the AC 0.4kv power supply system is generally used, which directly provides electricity from the substation, and the power load is large, which is not economical and environmentally friendly. In recent years, with the increasing greenhouse effect of the earth, a series of natural environmental problems have been caused, and people have begun to advocate low-carbon economy, especially energy recycling and reuse. Therefore, photovoltaic power generation and energy recycling in the power field have received special attention. There is no danger of solar energy being exhausted, and carbon dioxide will not be generated due to the use of solar energy. The excess energy generated during the operation of electrical equipment can be recycled and reused locally to save electricity.

[0003] In addition, the AC 0.4kV power supply system cable uses 4-core or 5-core cables, which are more expensive than the DC power supply with 2-core or 3-core cables. Moreover, with the development of the subway, the subway maintenance workshop has a large space, a large height difference between the ground and the roof, a height of up to 8 meters, and a length of more than 300 meters. The AC 0.4kV voltage is low, and the power supply is long over long distances, and the cable is long, so the loss is relatively large. Furthermore, due to the large load of the workshop, in the step-down substation with a single busbar segmented main connection, when one transformer is out of operation, the load rate of the other transformer is very high, and the efficiency will also decrease, which will also affect the life of the transformer. In addition, general LED ceiling lights use AC power supply, and there are many of them and they are installed at a high height. It is inconvenient to inspect and maintain them when the manual control and the internal driver of the lamp are damaged. There are also many industrial fans in the long workshop, and it is inconvenient to manually adjust the fan speed and switch individually. It is also possible that due to the negligence of the operating personnel, there are still inspection pit lighting, ceiling lights, DC fans and other equipment that are not turned off near the work area where there is no maintenance work, resulting in waste of resources. When subway batteries are undergoing discharge tests, the discharged electrical energy is lost in the form of heat energy, resulting in electrical energy loss.

[0004] Therefore, seeking a low-carbon, economical and easy-to-operate factory power supply system is of great significance to promoting the development of a conservation-oriented society. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing power supply system for factory buildings, such as being not low-carbon and environmentally friendly, having high costs, and being inconvenient to operate, and to provide a DC power supply system suitable for a vehicle base and a control method thereof.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A DC power supply system suitable for a vehicle base, comprising: at least one DC bus, a step-down substation, a photovoltaic system, an energy feedback module, an electric equipment module, a monitoring host, a communication manager, an on-site control panel, and a battery charging and discharging module, wherein the step-down substation, the photovoltaic system, the energy feedback module, and the battery charging and discharging module are all electrically connected to the DC bus, the electric equipment module is electrically connected to the energy feedback module and the on-site control panel, the monitoring host is communicatively connected to the step-down substation, and the monitoring host is communicatively connected to the on-site control panel, the battery charging and discharging module, the energy feedback module, the step-down substation, and the photovoltaic system through the communication manager;

[0008] The step-down substation comprises: a plurality of grid-connected modules, a plurality of step-down transformers, a plurality of bus-sectioning switches, and a plurality of busbars. The step-down transformers and the bus-sectioning switches are connected in a single-bus-sectioned main connection mode. A plurality of grid-connected modules and a step-down transformer are arranged on each of the busbars. Each of the busbars is electrically connected through the bus-sectioning switch, and each of the grid-connected modules is also electrically connected to the DC busbar.

[0009] The photovoltaic system comprises: a plurality of photovoltaic modules, a bidirectional DC / DC converter, and an energy storage battery, wherein the energy storage battery is electrically connected to one end of the bidirectional DC / DC converter, and the other end of the DC / DC converter and the photovoltaic module are both electrically connected to the DC bus;

[0010] The electrical equipment module comprises: a segmented insulator, a contact network, a one-way conducting device, a rail, a DC fan module, and a lighting module. The segmented insulator is arranged on the contact network, the contact network and the rail are electrically connected to the energy feedback module, the one-way conducting device is arranged on the rail, and the DC fan module and the lighting module are both electrically connected to the contact network and the rail;

[0011] The monitoring host is used to adjust the start and stop and operating status of each device according to user needs;

[0012] The local control panel is used to centrally control the DC fan module and the lighting module of the electrical equipment module;

[0013] The DC bus capable of adjusting voltage is used to combine various electrical devices, and the contact network is reused as a supplement to the DC bus.

[0014] By adopting the above technical solution, lighting, fans and other equipment that can be powered by DC are combined with all systems and equipment that can provide electric energy. The battery charging and discharging module and the energy feedback module can absorb electric energy and release excess and useless electric energy. The photovoltaic system can continuously provide clean energy. The step-down substation, as a part supporting the stability of the system, can obtain electric energy from the power grid when the local power is insufficient, and return electric energy to the medium-voltage power grid when the local power is in excess, so as to realize the utilization of renewable energy. The adjustable high-voltage DC bus is used to combine these equipment, and the contact network is reused as a supplement to the DC bus. Then, a comprehensive management system is used to reasonably allocate the electric energy between various systems by controlling various converters and switches, so as to realize low-carbon economic operation. The AC 0.4kv power supply system cable adopts 4-core or 5-core cable, which is 2-core or 3-core more than DC power supply. DC power supply can save cable costs. The DC bus can also increase the power supply voltage and reduce the power transmission loss. The voltage of the terminal equipment can be adjusted by the DC / DC converter to avoid the conversion of the generated DC into AC. At the same time, the 0.4kV step-down substation in the general vehicle base is powered by dual transformers. When one transformer is out of operation, the load rate of the other transformer is very high, even exceeding 110%. Therefore, this solution reduces the transformer load rate and maintenance time. Combined with DC power supply, the general LED ceiling lights are powered by AC, and there are many of them and the installation height is high. It is inconvenient to inspect and maintain them when the manual control and the internal driver of the lamp are damaged (LED damage is mostly caused by the driver, and the life of the LED itself can exceed 50,000 hours). This solution adopts a centralized drive method, placing the driver on the ground for easy maintenance and centralized control. It can also be combined with intelligent lighting to achieve stepless dimming and save energy. At the same time, the inspection pit safety lighting in the factory building can use DC power supply, which is convenient for unified management and avoids the waste of lights on after people or cars leave. In addition, there are many industrial fans in the long factory building, and it is inconvenient to manually adjust the fan speed and switch individually. This solution can realize the group stepless voltage and speed regulation and switch functions of the fan, which can avoid the situation where no one blows the fan, save energy and improve the comfort of blowing.

[0015] As a preferred solution of the present invention, the energy feedback module includes: a bidirectional DC / DC converter and a plurality of switches, one end of each of the bidirectional DC / DC converters is electrically connected to the DC bus through one of the switches, the positive electrode of the other end of the bidirectional DC / DC converter is electrically connected to the contact network through one of the switches, and the negative electrode of the other end of the bidirectional DC / DC converter is electrically connected to the rail through one of the switches.

[0016] As a preferred embodiment of the present invention, the DC fan module includes: a plurality of switches, a plurality of groups of DC fan modules, and a DC / DC converter, wherein the plurality of groups of DC fan modules are connected in parallel, one end of the DC / DC converter is electrically connected to the DC fan module, the positive electrode of the other end of the DC / DC converter is electrically connected to the contact network through the switch, and the negative electrode of the other end of the DC / DC converter is electrically connected to the rail through the switch.

[0017] As a preferred solution of the present invention, the DC fan unit includes a plurality of DC fans and a switch, the plurality of DC fans are connected in parallel and are electrically connected to the DC / DC converter via the switch.

[0018] As a preferred embodiment of the present invention, the lighting module includes: a first DC / DC converter, a second DC / DC converter, several groups of ceiling light modules, several trench lighting lamps, and several switches. Several of the trench lighting lamps are connected in parallel, and several groups of the ceiling light modules are connected in parallel. The positive electrode at one end of the first DC / DC converter is electrically connected to the contact network through one of the switches, the negative electrode at one end of the first DC / DC converter is electrically connected to the rail through one of the switches, and the other end is electrically connected to the ceiling light module. One end of the second DC / DC converter is electrically connected to the ceiling light module through the switch, and the other end is connected to the trench lighting lamp.

[0019] As a preferred solution of the present invention, the ceiling light module includes: a plurality of ceiling lights and a switch, the plurality of ceiling lights are connected in parallel and are electrically connected to the first DC / DC converter through the switch.

[0020] As a preferred solution of the present invention, the grid-connected module includes: two switches and a bidirectional AC / DC converter, and two ends of the bidirectional AC / DC converter are respectively connected to one of the switches.

[0021] As a preferred embodiment of the present invention, the photovoltaic module includes: a photovoltaic string, a DC / DC converter, and a switch, wherein the photovoltaic string is electrically connected to one end of the DC / DC converter, and the other end of the DC / DC converter is electrically connected to the DC bus through the switch.

[0022] As a preferred embodiment of the present invention, the DC power supply system also includes a battery charging and discharging module, which includes: a subway battery, a bidirectional DC / DC converter, and a switch. The subway battery is electrically connected to the bidirectional DC / DC converter, and the bidirectional converter is electrically connected to the DC bus through the switch.

[0023] On the other hand, a DC power supply control method applicable to a vehicle base is disclosed, and the DC power supply control method is applied to any of the above-mentioned DC power supply systems, comprising the following steps:

[0024] S1: Detect whether there are trains ready to enter the factory on each track in the factory. If yes, disable the electrical equipment connected to the contact network before the train stops, close the segmented insulator and connect the energy feedback module. According to the power demand in the factory, directly use the train braking feedback energy or store the train braking feedback energy in the energy storage battery. After the train stops, disconnect the segmented insulator, and then connect the required electrical equipment according to user needs, otherwise disconnect all electrical equipment;

[0025] S2: Determine whether the electric energy input on the DC bus is greater than the output, if not, execute step S3, if yes, execute step S4, and step S3 and step S4 can be interchanged;

[0026] S3: Activate a corresponding number of the grid-connected modules according to the power required by the DC side;

[0027] S4: Automatically adjust the input of electric energy according to the overflow electric energy and the electric energy required by the AC side, and enable a corresponding number of the grid-connected modules to feed back electric energy to the AC side;

[0028] S5: When the train leaves the factory, the electrical equipment connected to the contact network is forcibly disconnected, and the remaining electrical equipment and the grid-connected module are disconnected as needed. The energy feedback module is retained and connected. If there is excess energy in the DC bus, it is preferentially fed back to the contact network to provide traction power. After the train leaves the factory, the section insulator is disconnected, and the energy feedback module is disconnected as needed.

[0029] Compared with the prior art, the beneficial effects of the present invention are: combining lighting, fans and other equipment that can be powered by DC with all systems and equipment that can provide electrical energy; the battery charging and discharging module and the energy feedback module can absorb electrical energy and release excess and useless electrical energy, and are responsible for the connection between the DC bus and the contact network, and can disconnect and connect the two parts; the photovoltaic system can continuously provide clean energy; the step-down substation, as a part supporting the stability of the system, can obtain electrical energy from the power grid when the local power is insufficient, and return electrical energy to the medium-voltage power grid when the local power is in excess, thereby realizing renewable energy. The use of adjustable high-voltage DC bus combines these devices, and reuses the contact network as a supplement to the DC bus. The DC equipment directly obtains electrical energy through the contact network, reducing the need to lay another DC power supply line. Then a comprehensive management system is used to reasonably allocate electrical energy between various systems by controlling various converters and switches to achieve low-carbon economic operation; the AC 0.4kv power supply system cable uses 4-core or 5-core cables, which are 2-core or 3-core more than DC power supply. DC power supply can save cable costs, and the use of DC bus can also increase the power supply voltage and reduce power transmission losses. In addition, the voltage of the terminal equipment can be adjusted through the DC / DC converter, avoiding the loss in the process of converting the generated DC power into AC power and then converting it back to DC power; at the same time, the 0.4kV step-down substation in the general vehicle base adopts dual transformers for power supply. When one transformer is out of operation, the load rate of the other transformer is very high, even exceeding 110%. Therefore, this solution reduces the transformer load rate and maintenance time; combined with DC power supply, the general LED ceiling lights adopt AC power supply, and the number is large and the installation height is high. Manual control and damage to the internal driver of the lamp (LED damage is mostly caused by the driver, LED itself The service life of the fan can exceed 50,000 hours), which is inconvenient for inspection and maintenance. This solution adopts a centralized drive method and places the drive on the ground for easy maintenance and centralized control. It can also be combined with intelligent lighting to achieve stepless dimming and save energy. At the same time, the inspection pit safety lighting in the factory can be powered by DC, which is convenient for unified management and avoids the waste of lights on after people or cars leave. In addition, there are many industrial fans in the long factory, and it is not convenient to manually adjust the fan speed and switch individually. This solution can realize the group stepless voltage and speed regulation and switch functions of the fan, which can avoid the situation where no one is blowing the fan, save energy and improve the comfort of blowing. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural block diagram of a DC power supply system suitable for a vehicle base according to Embodiment 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of a DC power supply system applicable to a vehicle base according to Embodiment 1 of the present invention;

[0032] Figure 3This is a schematic diagram of a DC power supply system suitable for a vehicle base according to Embodiment 2 of the present invention;

[0033] Figure 4 This is a control schematic diagram of a DC power supply system applicable to a vehicle base according to Embodiment 2 of the present invention;

[0034] Figure 5 This is a flow chart of a DC power supply control method applicable to a vehicle base according to Embodiment 3 of the present invention;

[0035] Markings in the figure: 1-DC bus, 2-0.4kv step-down transformer, 3-segmented insulator, 4-contact network, 5-unidirectional conduction device, 6-rail, 7-DC fan, 8-ditch lighting, 9-ceiling light, 10-subway train, 11-step-down substation, 12-photovoltaic system, 13-subway battery, 14-energy storage battery, 15-photovoltaic string, 16-communication interface, QS1-bus segment switch, M1-photovoltaic module, M2-grid-connected module, M3-battery charging and discharging module, M4-energy feedback module, 01-monitoring host, 02-communication manager, 03-photovoltaic monitoring system, 04-local control panel, 001-first bidirectional DC / DC converter, 002 -the second bidirectional DC / DC converter, 003-the third DC / DC converter, 004-the fourth bidirectional AC / DC converter, 005-the fifth bidirectional DC / DC converter, 006-the sixth DC / DC converter, 007-the seventh DC / DC converter, 008-the eighth DC / DC converter, K1-the first switch, K2-the second switch, K3-the third switch, K4-the fourth switch, K5-the fifth switch, K6-the sixth switch, K7-the seventh switch, K8-the eighth switch, K9-the ninth switch, K10-the tenth switch, K11-the eleventh switch, K12-the twelfth switch, K13-the thirteenth switch, K14-the fortieth switch, K15-the fifteenth switch. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0037] Example 1

[0038] A DC power supply system suitable for a vehicle base, such as Figure 1As shown, it includes: at least one DC bus, a step-down substation, a photovoltaic system, an energy feedback module, an electric equipment module, a monitoring host, a communication manager, an on-site control panel, and a battery charging and discharging module. The step-down substation, the photovoltaic system, the energy feedback module, and the battery charging and discharging module are all electrically connected to the DC bus, the electric equipment module is electrically connected to the energy feedback module and the on-site control panel, the monitoring host is communicatively connected to the step-down substation, and the monitoring host is communicatively connected to the on-site control panel, the battery charging and discharging module, the energy feedback module, and the photovoltaic system through the communication manager;

[0039] like Figure 2 As shown, the step-down substation includes: a plurality of grid-connected modules, a plurality of step-down transformers (0.4kv step-down transformers), a plurality of bus segmentation switches, and a plurality of busbars. The step-down transformers and the bus segmentation switches are connected in a single bus segmentation main connection mode. A plurality of grid-connected modules and a step-down transformer are arranged on each busbar. Each busbar is electrically connected through the bus segmentation switch, and each grid-connected module is also electrically connected to the DC busbar.

[0040] The photovoltaic system comprises: a plurality of photovoltaic modules, a bidirectional DC / DC converter, and an energy storage battery, wherein the energy storage battery is electrically connected to one end of the bidirectional DC / DC converter, and the other end of the DC / DC converter and the photovoltaic module are both electrically connected to the DC bus;

[0041] The electrical equipment module comprises: a segmented insulator, a contact network, a one-way conducting device, a rail, a DC fan module, and a lighting module. The segmented insulator is arranged on the contact network, the contact network and the rail are electrically connected to the energy feedback module, the one-way conducting device is arranged on the rail, and the DC fan module and the lighting module are both electrically connected to the contact network and the rail;

[0042] The monitoring host is used to adjust the start and stop and operating status of each device according to user needs;

[0043] The local control panel is used to centrally control the DC fan module and the lighting module of the electrical equipment module;

[0044] The various electrical equipment are combined using the voltage-adjustable DC bus, and the contact network is reused as a supplement to the DC bus. A comprehensive management system is then used to reasonably allocate electrical energy between various systems by controlling various converters and switches, thereby achieving low-carbon economic operation.

[0045] The energy feedback module includes: a bidirectional DC / DC converter and a plurality of switches, one end of each of the bidirectional DC / DC converters is electrically connected to the DC bus through one of the switches, the positive electrode of the other end of the bidirectional DC / DC converter is electrically connected to the contact network through one of the switches, and the negative electrode of the other end of the bidirectional DC / DC converter is electrically connected to the rail through one of the switches.

[0046] The DC fan module includes: a plurality of switches, a plurality of groups of DC fan modules, and a DC / DC converter. The plurality of groups of DC fan modules are connected in parallel, one end of the DC / DC converter is electrically connected to the DC fan module, the positive electrode of the other end of the DC / DC converter is electrically connected to the contact network through the switch, and the negative electrode of the other end of the DC / DC converter is electrically connected to the rail through the switch.

[0047] The DC fan unit comprises a plurality of DC fans and a switch. The DC fans are connected in parallel and are electrically connected to the DC / DC converter via the switch.

[0048] The lighting module includes: a first DC / DC converter, a second DC / DC converter, several groups of ceiling light modules, several trench lighting lamps, and several switches. Several of the trench lighting lamps are connected in parallel, and several groups of the ceiling light modules are connected in parallel. The positive electrode of one end of the first DC / DC converter is electrically connected to the contact network through one of the switches, the negative electrode of one end of the first DC / DC converter is electrically connected to the rail through one of the switches, and the other end is electrically connected to the ceiling light module. One end of the second DC / DC converter is electrically connected to the ceiling light module through the switch, and the other end is connected to the trench lighting lamp.

[0049] The ceiling light module includes: a plurality of ceiling lights and a switch. The plurality of ceiling lights are connected in parallel and are electrically connected to the first DC / DC converter through the switch.

[0050] The grid-connected module comprises: two switches and a bidirectional AC / DC converter, and two ends of the bidirectional AC / DC converter are respectively connected to one of the switches.

[0051] The photovoltaic module includes: a photovoltaic string, a DC / DC converter, and a switch. The photovoltaic string is electrically connected to one end of the DC / DC converter, and the other end of the DC / DC converter is electrically connected to the DC bus through the switch.

[0052] The DC power supply system also includes a battery charging and discharging module, which includes: a subway battery, a bidirectional DC / DC converter, and a switch. The subway battery is electrically connected to the bidirectional DC / DC converter, and the bidirectional converter is electrically connected to the DC bus through the switch.

[0053] Specifically, the contact network can be used as a DC bus, and DC power-consuming equipment is connected to the contact network for power consumption. The energy feedback module is responsible for the connection between the DC bus and the contact network, and can disconnect and connect the two parts. When a train enters, energy is fed back from the contact network to the DC bus. After the train stops, the connection between the contact network and the outside of the factory is disconnected, and the contact network is used as a DC bus. DC equipment directly obtains electrical energy through the contact network, reducing the need to lay another DC power supply line.

[0054] By adopting the above technical solution, lighting, fans and other equipment that can be powered by DC are combined with all systems and equipment that can provide electric energy. The battery charging and discharging module and the energy feedback module can absorb electric energy and release excess and useless electric energy. The photovoltaic system can continuously provide clean energy. The step-down substation, as a part supporting the stability of the system, can obtain electric energy from the power grid when the local power is insufficient, and return electric energy to the medium-voltage power grid when the local power is in excess, so as to realize the utilization of renewable energy. The adjustable high-voltage DC bus is used to combine these equipment, and the contact network is reused as a supplement to the DC bus. Then, a comprehensive management system is used to reasonably allocate the electric energy between various systems by controlling various converters and switches, so as to realize low-carbon economic operation. The AC 0.4kv power supply system cable adopts 4-core or 5-core cable, which is 2-core or 3-core more than DC power supply. DC power supply can save cable costs. The DC bus can also increase the power supply voltage and reduce the power transmission loss. The voltage of the terminal equipment can be adjusted by the DC / DC converter to avoid the conversion of the generated DC into AC. At the same time, the 0.4kV step-down substation in the general vehicle base is powered by dual transformers. When one transformer is out of operation, the load rate of the other transformer is very high, even exceeding 110%. Therefore, this solution reduces the transformer load rate and maintenance time. Combined with DC power supply, the general LED ceiling lights are powered by AC, and there are many of them and the installation height is high. It is inconvenient to inspect and maintain them when the manual control and the internal driver of the lamp are damaged (LED damage is mostly caused by the driver, and the life of the LED itself can exceed 50,000 hours). This solution adopts a centralized drive method, placing the driver on the ground for easy maintenance and centralized control. It can also be combined with intelligent lighting to achieve stepless dimming and save energy. At the same time, the inspection pit safety lighting in the factory building can use DC power supply, which is convenient for unified management and avoids the waste of lights on after people or cars leave. In addition, there are many industrial fans in the long factory building, and it is inconvenient to manually adjust the fan speed and switch individually. This solution can realize the group stepless voltage and speed regulation and switch functions of the fan, which can avoid the situation where no one blows the fan, save energy and improve the comfort of blowing.

[0055] Example 2

[0056] This embodiment is a specific embodiment of embodiment 1;

[0057] like Figure 3As shown, the DC power supply system includes: a DC bus 1, a segmented insulator 3, a contact network 4, a unidirectional conduction device 5, a rail 6, a DC fan 7, a trench lighting lamp 8, a ceiling lamp 9, a subway train 10, a step-down substation 11, a photovoltaic system 12, a first bidirectional DC / DC converter 001, a fifth bidirectional DC / DC converter 005, a sixth DC / DC converter 006, a seventh DC / DC converter 007, an eighth DC / DC converter 008, a first switch K1, a tenth switch K10, an eleventh switch K11, a twelfth switch K12, a thirteenth switch K13, a fourteenth switch K14, and a fifteenth switch K15.

[0058] Specifically, the photovoltaic system 12 includes: an energy storage battery 14, a photovoltaic string 15, a second bidirectional DC / DC converter 002, a third bidirectional DC / DC converter 003, a second switch K2 connected to the DC bus 1, and a third switch K3, wherein the photovoltaic string 15, the third bidirectional DC / DC converter 003, and the third switch K3 form a group of photovoltaic modules M1, and the number of photovoltaic modules can be adjusted according to the power demand of the entire project. The third switch K3 includes a group of switches K3-1 to K3-n (n is a positive integer), which refers to the switches in all photovoltaic modules. The step-down substation 11 includes: a fourth bidirectional DC / DC converter 004, a fifth switch K5, a seventh switch K7, an eighth switch K8, a ninth switch K9, a 0.4 kV step-down transformer 2, a bus segmentation switch QS1, a fourth switch K4 connected to the DC bus 1, and a sixth switch K6, wherein the fourth switch K4, the fourth bidirectional DC / DC converter 004, and the fifth switch K5 form a group of grid-connected modules M2 or the sixth switch K6, the fourth bidirectional DC / DC converter 004, and the seventh switch K7 form a group of grid-connected modules M2, and the number of modules can be adjusted according to the energy conversion requirements of the system, the fourth switch K4 includes a group of switches K4-1 to K4-n (n is a positive integer), the fifth switch K5 includes a group of switches K5-1 to K5-n (n is a positive integer), the sixth switch K6 includes a group of switches K6-1 to K6-n (n is a positive integer), and the seventh switch K7 includes a group of switches K7-1 to K7-n (n is a positive integer). The step-down substation 11 adopts a single busbar segmented main connection. A certain number of grid-connected modules M2 can be set on both buses. When a transformer is out of operation, the busbar segmentation switch QS1 is closed. When the energy on the DC side flows in the reverse direction, multiple grid-connected modules can simultaneously supply power to the AC load, reducing the load rate when a single transformer is in operation. When the energy on the AC side flows in the forward direction, multiple grid-connected modules can simultaneously supply power to the DC load to meet all power needs.

[0059] The first switch K1 is connected between the first bidirectional DC / DC converter 001 and the DC bus 1, and the first switch K1, the first bidirectional DC / DC converter 001, and the DC bus 1 form a group of battery charging and discharging modules M3, and the user can adjust the number of modules connected to the DC bus 1 according to the subway maintenance work. The tenth switch K10 is connected between the fifth bidirectional DC / DC converter 005 and the DC bus 1, and the eleventh switch K11 is connected between the fifth bidirectional DC / DC converter 005 and the contact network 4 and the rail 6, and the tenth switch K10, the fifth bidirectional DC / DC converter 005, and the eleventh switch K11 form a group of energy feedback modules M4, and the user can adjust the number of energy feedback modules M4 according to the number of tracks in the factory.

[0060] The contact network 4 is connected to the energy feedback module M4, the sixth DC / DC converter 006, and the eighth DC / DC converter. When the subway train 10 enters the factory building, the segmented insulator 3 disconnects the contact network outside the factory building, and the one-way conduction device 5 on the rail prevents external current from entering. The contact network 4, as a supplement to the DC bus 1, can be connected to a variety of DC power equipment, saving DC bus investment.

[0061] The sixth DC / DC converter 006 has an input end connected to the twelfth switch K12 and the overhead contact network 4, and an output end connected to the ceiling light 9, the fourteenth switch K14, and the seventh DC / DC converter, wherein the ceiling light 9 can be divided into multiple groups for control. The seventh DC / DC converter 007 has an output end connected to the trench lighting lamp 8, and an input end connected to the fourteenth switch K14 and the sixth DC / DC converter, wherein the trench lighting lamp 8 can be divided into multiple groups for control, and the fourteenth switch K14 includes a group of switches K14-1 to K14-n (n is a positive integer), which refers to all switches connected to the output end of the sixth DC / DC converter 006. The sixth DC / DC converter 006 and the seventh DC / DC converter 007 cooperate with each other in constant current control, saving cables connected to the overhead contact network 4 and the rails 5, and at the same time, the brightness of the trench lighting lamp 8 and the ceiling light 9 can be adjusted. Specifically, the sixth DC / DC converter 006 and the seventh DC / DC converter 007 both have input and output current and voltage detection. When the current of the ditch lighting lamp 8 changes due to the adjustment of the seventh DC / DC converter 007, the sixth DC / DC converter 006 detects the changed current and then adjusts the output current to compensate for the changed current, so that the current of the ceiling light 9 remains constant, ensuring accurate brightness control. When the current of the ceiling light 9 changes due to the adjustment of the sixth DC / DC converter 006, the output setting of the seventh DC / DC converter 007 is kept unchanged, and the output current of the sixth DC / DC converter 006 is stably adjusted.

[0062] The eighth DC / DC converter 008 has an input end connected to the thirteenth switch K13 and the contact network 4, and an output end connected to the DC fan 7 and the fifteenth switch K15, wherein the DC fan 7 can be controlled in multiple groups, and the fan speed is controlled by controlling the output voltage of the eighth DC / DC converter 008. The fifteenth switch K15 includes a group of switches K15-1 to K15-n (n is a positive integer), which refers to all switches connected to the output end of the eighth DC / DC converter 008.

[0063] like Figure 4 As shown, the DC bus 1 spans over the L1 to Ln tracks in the factory. The DC bus 1 is connected to the rooftop photovoltaic system 12, the substation 11, each group of energy feedback modules M4, and the battery charging and discharging module M3. More devices can be connected to the DC bus 1 according to actual needs.

[0064] Furthermore, if Figure 4As shown, the monitoring host 01 is used to adjust the start and stop and use functions of each device according to user needs, including the monitoring of the photovoltaic power generation system. The user mainly issues relevant demand instructions through the local control panel 04 and the monitoring host 01 to monitor the energy flow of each device and adjust the energy interaction with the AC side of the substation in real time. In other words, based on user needs, the grid-connected energy of the entire DC system and the substation is adjusted to switch between forward and reverse directions to ensure the priority use of renewable energy and energy storage energy. When it is insufficient to meet the electricity demand, supplementary electricity is connected from the substation. When there is excess renewable energy, , according to the power demand of the AC side of the substation, the excess energy is fed back to the AC side of the substation. If the excess energy is too much, the discharge energy of the subway battery 13 is reduced first, that is, the discharged energy can be directly consumed by the output parallel resistor of the first bidirectional DC / DC converter, and then the reverse energy output of the energy storage battery 14 of the second bidirectional DC / DC converter 002 is reduced. If it is still excessive, the reverse output of the subway braking energy of the fifth bidirectional DC / DC converter 005 is reduced. If it is still excessive, the reverse photovoltaic power generation output of the third DC / DC converter 003 is reduced. Among them, the control algorithm of the bidirectional AC / DC converter 004 can adopt DQ decoupling and PID control, which mainly functions to stabilize the voltage of the DC bus 1, and the energy flow is realized through the regulation of the remaining DC / DC converters. The communication manager 02 is used to collect the communication buses connecting the local control panel 04, the first bidirectional DC / DC converter 001, the fifth bidirectional DC / DC converter 005, the sixth DC / DC converter 006, the seventh DC / DC converter 007, and the eighth DC / DC converter 008, and after the information is collected, the monitoring information is transmitted up and down with the monitoring host 01 through a communication interface, which is convenient for centralized management. The monitoring host 01 also has a reserved communication interface 16, which can realize information exchange with other monitoring systems, such as communication with the building equipment automation system. The communication bus can use optical fiber or communication cable, and the communication protocol can use MODBUS or BACnet.

[0065] It should also be noted that the voltage on the DC bus 1 can be a higher voltage, such as high voltage transmission between 700 and 1200 V, so as to reduce transmission loss. The motor of the DC fan 7 can be a DC brushless motor to improve efficiency, and accept a DC power supply to drive the fan to rotate. The power supply voltage can be DC48V, DC110V, DC220V, etc.

[0066] The sixth DC / DC converter 006 and the seventh DC / DC converter 007 can adopt an interleaved parallel BUCK topology to reduce the fluctuation of the output voltage and current to avoid light flickering, and also meet the step-down conversion of the DC voltage on the contact network 4, and provide the converted DC power to the ceiling light 9 and the trench lighting lamp 8. The input control condition of the sixth DC / DC converter 006 also includes an illumination sensor in the factory. When the illumination does not meet the specified requirements, the output current is adjusted to meet the requirements. In addition, the feedback value of the illumination sensor can be the information of multiple sensors in the factory. The sixth DC / DC converter 006 can be multiple groups to achieve multi-directional control of illumination. The output voltage and current of the sixth DC / DC converter 006 and the seventh DC / DC converter 007 can be adjusted by the command of manual control of the brightness of the lamp by the monitoring host 01 or the local control panel 04, or can be automatically adjusted in real time according to the illumination reflected by the illumination sensor 05 in the factory by setting the target value. The two modes can be switched to each other.

[0067] The eighth DC / DC converter 008 can be a multi-stage buck or a single-stage buck. When the DC fan 7 is powered by a lower voltage for safety considerations, the eighth DC / DC converter 008 can be a multi-stage BUCK topology buck. When a higher voltage is used for power supply considering the comfort and economy of the DC fan 7, the eighth DC / DC converter 008 can be a single-stage BUCK topology buck. The output voltage and current of the eighth DC / DC converter 008 can be adjusted by the fan speed adjustment command of the monitoring host 01 or the local control panel 04.

[0068] The fifth DC / DC converter 005 can adopt a bidirectional CLLLC type DC / DC converter, which is used to convert the energy generated by the subway entering the factory and transmit the converted DC power to the DC bus 1, or when the train is under maintenance, the DC power supply of the DC bus 1 is converted and transmitted to the contact network 4 to provide power for electrical equipment such as ceiling lights 9 and DC fans 7. The bidirectional CLLLC type DC / DC converter can operate in a resonant state and maintain a high-efficiency state. It contains an isolation transformer, which can isolate the contact network from the DC bus and play a safety isolation role.

[0069] The third DC / DC converter 003 can adopt a BUCK / BOOST step-up / step-down DC / DC converter topology to convert the DC power output of the photovoltaic string 15, and transmit the converted DC power to the DC bus 1 for distribution. The third DC / DC converter 003 can adjust the output power according to the power demand, and can also realize photovoltaic maximum power tracking.

[0070] The first DC / DC converter 001 and the second DC / DC converter 002 can adopt bidirectional CLLLC type DC / DC converters, which include an isolation transformer, which can isolate the high-voltage DC bus and the battery, and play a role in safety isolation. The bidirectional CLLLC type DC / DC converter is used to provide DC power when the subway battery 13 needs to be charged, store the excess energy in the energy storage battery 14 when there is excess renewable energy, convert the released electric energy to the DC bus 1 for distribution when the subway battery 13 needs to be discharged, and release the electric energy of the energy storage battery 14 to the DC bus 1 when the system power demand is large. The first DC / DC converter 001 also includes a resistor discharge circuit, which releases the electric energy of the subway battery 13 when it must be discharged to the resistor when there is excess electric energy in the DC bus.

[0071] The fourth bidirectional AC / DC converter 004 can adopt a T-type three-level topology to improve conversion efficiency, and is used to convert the DC power of the DC bus 1 and transmit the converted AC power to the AC 0.4kV bus, or to convert the AC power on the AC 0.4kV bus and transmit the converted DC power to the DC bus 1. The fourth bidirectional AC / DC converter 004 operates in a DC side constant voltage control mode, and the current magnitude and flow direction are determined by the current magnitude and direction injected into the DC bus 1 by the first bidirectional DC / DC converter 001, the second bidirectional DC / DC converter, the third DC / DC converter, and the fifth bidirectional DC / DC converter.

[0072] In addition, all bidirectional DC / DC converters, DC / DC converters, and bidirectional AC / DC converters are equipped with digital controllers or microcontrollers, optical fiber interfaces, and communication interfaces, and the switch devices can all use high-efficiency devices such as silicon carbide MOSFET and gallium nitride MOSFET to reduce the loss of the entire DC system. All converters can be connected to the monitoring host and local control panel through the bus to achieve arbitrary network control. The local control panel can be set at a convenient control location in any factory building, and can be a touch screen with personnel management and password system. It can monitor the operating status of each group of equipment and issue control instructions to each group of equipment. In the system, except for the eighth switch K8, the ninth switch K9, and the section switch QS1, which are controlled by the AC 0.4kV low-voltage system, all circuit breakers can be directly connected and disconnected by sending signals directly from the digital controller or microcontroller in the nearest connected converter. When laying the rails, consider the insulation treatment with other metal facilities to avoid stray current from corroding the metal facilities in the factory building.

[0073] It should also be noted that all electrical equipment can be connected to the nearby contact network or DC bus, saving cable investment.

[0074] Example 3

[0075] A DC power supply control method applicable to a vehicle base, wherein the DC power supply control method is applied to the DC power supply system described in Example 1 or Example 2, such as Figure 5 As shown, the following steps are included:

[0076] S1: Check whether there are trains ready to enter the factory on each track in the factory. If so, disable the electrical equipment connected to the contact network before the train stops, close the segmented insulator and connect the energy feedback module. Directly use the train braking feedback energy or store the train braking feedback energy in the energy storage battery according to the power demand in the factory. After the train stops, disconnect the segmented insulator, and then connect the required electrical equipment according to user needs. That is to say, the segmented insulator is in a disconnected state before the train enters the factory, and the user chooses to enable the electrical equipment according to needs. When the train is detected to enter the factory, for safety reasons, immediately disconnect the electrical equipment connected to the contact network and close the segmented insulator, and connect the energy feedback module to recover braking energy. When the train stops, disconnect the segmented insulator to isolate the external contact network. At this time, the user can enable all electrical equipment; otherwise, disconnect all electrical equipment. That is to say, when the subway vehicle has not entered the factory for maintenance, in order to save electricity, the relevant electrical equipment is generally not enabled, but can be forced to start according to user needs;

[0077] S2: Determine whether the electric energy input on the DC bus is greater than the output, if not, execute step S3, if yes, execute step S4, and step S3 and step S4 can be interchanged;

[0078] S3: Activate a corresponding number of the grid-connected modules according to the power required by the DC side;

[0079] S4: Automatically adjust the input of electric energy according to the overflow electric energy and the electric energy required by the AC side, and enable a corresponding number of the grid-connected modules to feed back electric energy to the AC side;

[0080] That is to say, due to actual operation needs, the two states of S3 and S4 can be switched to each other during operation. The monitoring host needs to collect the power consumption of each power-consuming device, the power output of the photovoltaic system, the output of the energy storage battery, and the power consumption of the AC side equipment of the substation to determine how to connect to the grid-connected module. First, determine whether the substation is in a state of two transformers operating independently or a single transformer operating and bus connection. If the two transformers are in an independent operation state, calculate the transformer load rate of the two bus sections. When the real-time measurement of the DC bus is overflow, the grid-connected module on the bus section with a load rate lower than the economic operation load rate and lower by a large amount is connected. If the transformer load rate is higher than the economic operation load rate, the grid-connected module on the bus section with a lower load rate is connected. When the real-time measurement of the DC bus requires supplementation, the grid-connected module on the bus section with a load rate higher than the economic operation load rate and higher by a large amount is connected. If the transformer load rate is lower than the economic operation load rate, the grid-connected module on the bus section with a lower load rate is connected. If a single transformer is running and the bus is connected, detect which bus has more AC load. When the real-time measurement of the DC bus shows that the power is overflowing, connect the grid-connected module of the bus with more load. When the real-time measurement of the DC bus shows that the power needs to be supplemented, connect the grid-connected module of the bus with less load. In addition, it is necessary to add power limits to the grid-connected modules, and each converter will also adjust the input and output in time. The power fed back to the AC side cannot exceed the required power. When supplementing the power on the DC side, the transformer cannot be overloaded for a long time. This protects the transformer as much as possible and makes the transformer operate close to the most economical state.

[0081] S5: When the train leaves the factory, the electrical equipment connected to the contact network is forcibly disconnected, and the remaining electrical equipment and the grid-connected module are disconnected as needed. The energy feedback module is retained and connected. If there is excess energy in the DC bus, it is preferentially fed back to the contact network to provide traction power. After the train leaves the factory, the segmented insulator is disconnected, and the energy feedback module is disconnected as needed.

[0082] That is to say, when the train is overhauled and ready to leave the factory, the monitoring host receives the train departure signal and for safety reasons, it forcibly disconnects the electrical equipment connected to the contact network. The energy feedback module converts the excess electrical energy on the DC bus and uses the converted electrical energy for traction power supply.

[0083] It should be noted that when the DC system is initialized at the beginning, at least one group of grid-connected modules are started on each of the two substation buses, wherein the fourth switch and the fifth switch are both closed or the sixth switch and the seventh switch are both closed, and the fourth bidirectional DC / DC converter enters the stable DC bus voltage mode. If multiple groups of grid-connected modules are connected in parallel, there are also anti-circulation measures. Afterwards, other DC devices are connected to the DC bus or grid-connected modules are added. During the whole process, the photovoltaic system is always online and is disconnected when necessary, such as when a fault occurs or maintenance occurs.

[0084] Furthermore, the grid-connected module may include a fourth switch, a fourth bidirectional DC / DC converter, a fifth switch or a sixth switch, a fourth bidirectional DC / DC converter, and a seventh switch. Furthermore, the photovoltaic system may include a photovoltaic module, an energy storage battery, a second bidirectional DC / DC converter, and a second switch, wherein the photovoltaic module includes a photovoltaic string, a third bidirectional DC / DC converter, and a third switch. The second switch and the third switch are always in a closed state, and a disconnection instruction is issued when the equipment needs maintenance or when necessary. According to the power demand of the DC system and the output characteristics of the photovoltaic module, the third bidirectional DC / DC converter is controlled to adjust the output of photovoltaic power generation.

[0085] Furthermore, each electrical equipment includes ceiling lights, DC fans, trench lighting lamps, subway batteries, etc. Among them, the power supply of DC fans, ceiling lights, and trench lighting lamps arranged in large quantities in the factory is drawn from the contact network, and the drive control is respectively the eighth DC / DC converter, the sixth DC / DC converter, and the seventh DC / DC converter. According to user needs, when starting DC fans, ceiling lights, trench lighting lamps and other equipment, the eleventh switch and the tenth switch are closed at the same time, and the fifth bidirectional DC / DC converter enters the reverse output state of the DC bus to the contact network, and then the twelfth switch, the thirteenth switch, the fourteenth switch, and the fifteenth switch are closed. The power supply of the subway battery can be directly drawn from the DC bus. When starting the charging and discharging of the subway battery, the first switch is closed, and the drive control is the first bidirectional DC / DC converter. When set to the battery charging mode, the first converter absorbs electric energy from the DC bus according to the set charging power. When set to the subway battery discharging mode, if it is determined that there is excess electric energy on the DC bus, the electric energy is released to the resistor, otherwise it is released to the DC bus.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A DC power supply system suitable for a vehicle base, characterized in that: include: At least one DC bus, a step-down substation, a photovoltaic system, an energy feedback module, an electric equipment module, a monitoring host, a communication manager, an on-site control panel, and a battery charging and discharging module. The step-down substation, the photovoltaic system, the energy feedback module, and the battery charging and discharging module are all electrically connected to the DC bus, the electric equipment module is electrically connected to the energy feedback module and the on-site control panel, the monitoring host is communicatively connected to the step-down substation, and the monitoring host is communicatively connected to the on-site control panel, the battery charging and discharging module, the energy feedback module, the step-down substation, and the photovoltaic system through the communication manager; The step-down substation comprises: a plurality of grid-connected modules, a plurality of step-down transformers, a plurality of bus-sectioning switches, and a plurality of busbars. The step-down transformers and the bus-sectioning switches are connected in a single-bus-sectioned main connection mode. A plurality of grid-connected modules and a step-down transformer are arranged on each of the busbars. Each of the busbars is electrically connected through the bus-sectioning switch, and each of the grid-connected modules is also electrically connected to the DC busbar. The photovoltaic system comprises: a plurality of photovoltaic modules, a bidirectional DC / DC converter, and an energy storage battery, wherein the energy storage battery is electrically connected to one end of the bidirectional DC / DC converter, and the other end of the DC / DC converter and the photovoltaic module are both electrically connected to the DC bus; The electrical equipment module comprises: a segmented insulator, a contact network, a one-way conducting device, a rail, a DC fan module, and a lighting module. The segmented insulator is arranged on the contact network, the contact network and the rail are electrically connected to the energy feedback module, the one-way conducting device is arranged on the rail, and the DC fan module and the lighting module are both electrically connected to the contact network and the rail; The monitoring host is used to adjust the start and stop and operating status of each electrical device according to user needs; The local control panel is used to centrally control the DC fan module and the lighting module of the electrical equipment module; The DC bus capable of adjusting voltage is used to combine various electrical devices, and the contact network is reused as a supplement to the DC bus.

2. A DC power supply system suitable for a vehicle base according to claim 1, characterized in that: The energy feedback module includes: a bidirectional DC / DC converter and a plurality of switches, one end of each of the bidirectional DC / DC converters is electrically connected to the DC bus through one of the switches, the positive electrode of the other end of the bidirectional DC / DC converter is electrically connected to the contact network through one of the switches, and the negative electrode of the other end of the bidirectional DC / DC converter is electrically connected to the rail through one of the switches.

3. A DC power supply system suitable for a vehicle base according to claim 1, characterized in that: The DC fan module includes: a plurality of switches, a plurality of groups of DC fan units, and a DC / DC converter. The plurality of groups of DC fan units are connected in parallel, one end of the DC / DC converter is electrically connected to the DC fan module, the positive pole of the DC / DC converter is electrically connected to the contact network through one of the switches, and the negative pole of the other end of the DC / DC converter is electrically connected to the rail through one of the switches.

4. A DC power supply system suitable for a vehicle base according to claim 3, characterized in that: The DC fan unit comprises a plurality of DC fans and a switch. The DC fans are connected in parallel and are electrically connected to the DC / DC converter via the switch.

5. A DC power supply system suitable for a vehicle base according to claim 3, characterized in that: The lighting module includes: a first DC / DC converter, a second DC / DC converter, several groups of ceiling light modules, several trench lighting lamps, and several switches. Several of the trench lighting lamps are connected in parallel, and several groups of the ceiling light modules are connected in parallel. The positive electrode of one end of the first DC / DC converter is electrically connected to the contact network through one of the switches, the negative electrode of one end of the first DC / DC converter is electrically connected to the rail through one of the switches, and the other end is electrically connected to the ceiling light module. One end of the second DC / DC converter is electrically connected to the ceiling light module through the switch, and the other end is connected to the trench lighting lamp.

6. A DC power supply system suitable for a vehicle base according to claim 5, characterized in that: The ceiling light module includes: a plurality of ceiling lights and a switch. The plurality of ceiling lights are connected in parallel and are electrically connected to the first DC / DC converter through the switch.

7. A DC power supply system suitable for a vehicle base according to claim 1, characterized in that: The grid-connected module comprises: two switches and a bidirectional AC / DC converter, and two ends of the bidirectional AC / DC converter are respectively connected to one of the switches.

8. A DC power supply system suitable for a vehicle base according to claim 1, characterized in that: The photovoltaic module includes: a photovoltaic string, a DC / DC converter, and a switch. The photovoltaic string is electrically connected to one end of the DC / DC converter, and the other end of the DC / DC converter is electrically connected to the DC bus through the switch.

9. A DC power supply system suitable for a vehicle base according to claim 1, characterized in that: The battery charging and discharging module includes: a subway battery, a bidirectional DC / DC converter, and a switch. The subway battery is electrically connected to the bidirectional DC / DC converter, and the bidirectional converter is electrically connected to the DC bus through the switch.

10. A DC power supply control method suitable for a vehicle base, characterized in that: The DC power supply control method is applied to the DC power supply system according to any one of claims 1 to 9, comprising the following steps: S1: Detect whether there are trains ready to enter the factory on each track in the factory. If yes, disable the electrical equipment connected to the contact network before the train stops, close the segmented insulator and connect the energy feedback module. According to the power demand in the factory, directly use the train braking feedback energy or store the train braking feedback energy in the energy storage battery. After the train stops, disconnect the segmented insulator, and then connect the required electrical equipment according to user needs, otherwise disconnect all electrical equipment; S2: Determine whether the electric energy input on the DC bus is greater than the output, if not, execute step S3, if yes, execute step S4, and step S3 and step S4 can be interchanged; S3: Activate a corresponding number of the grid-connected modules according to the power required by the DC side; S4: Automatically adjust the input of electric energy according to the overflow electric energy and the electric energy required by the AC side, and enable a corresponding number of the grid-connected modules to feed back electric energy to the AC side; S5: When the train leaves the factory, the electrical equipment connected to the contact network is forcibly disconnected, and the remaining electrical equipment and the grid-connected module are disconnected as needed. The energy feedback module is retained and connected. If there is excess energy in the DC bus, it is preferentially fed back to the contact network to provide traction power. After the train leaves the factory, the section insulator is disconnected, and the energy feedback module is disconnected as needed.

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