Power box and control method thereof

Abstract

The invention relates to the field of rail transit, in particular to a power box and a control method thereof.The power box comprises a charger connected with a train power supply network; the charger controller controls the operation of the charger; the storage battery pack is connected with the charger; the storage battery pack temperature sensor is used for detecting the temperature of the storage battery pack in real time; a charging current sensor for detecting the charging current of the storage battery pack; the charger output voltage sensor is used for detecting the charging voltage of the storage battery pack; an input voltage sensor for detecting an input voltage of the charger; the charger controller controls the switching frequency of a power switching device in the charger and sets a circuit parameter threshold value; judging whether the current power supply system is a direct-current power supply system or an alternating-current power supply system according to the input voltage; and according to the current power supply system, the circuit parameter threshold, and the charging current and the charging voltage detected in real time, adjusting the charging current and the charging voltage output by the charger to the storage battery pack. The problems that the charging current output by the charger fluctuates and the storage battery is damaged are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail transit, and in particular to a power supply box and a control method thereof. BACKGROUND

[0002] Under the background of cross-border intermodal initiative and four-network integration of rail transit, the train needs to adapt to multiple power supply systems, so that the rail transit train can run normally without stopping and transferring under multiple power supply systems. Taking the domestic double-flow train through operation as an example, the train needs to adapt to the subway 1500V DC power supply system and the suburban railway 25kV AC power supply system.

[0003] In the prior art, when the train is converted from a DC power supply system to an AC power supply system, the traditional voltage loop control adapted to the subway 1500V DC power supply system cannot be directly applied to the suburban railway. After AC rectification of the suburban railway, the DC power containing 100Hz fluctuation is output, which causes abnormal output of the charger, and the battery is easily damaged during the charging process of the charger to the battery.

[0004] At present, there is no effective solution to the problem that the current output by the charger in the related technology fluctuates, causing damage to the battery. SUMMARY

[0005] Embodiments of the present application provide a power supply box and a control method thereof to at least solve the problem that the current output by the charger in the related technology fluctuates, causing damage to the battery.

[0006] In a first aspect, the embodiments of the present application provide a power supply box adapted to a DC power supply system and an AC power supply system, the power supply box being connected to a train power supply network, and comprising: a charger and a charger controller, the charger comprising a power switching device and an isolation transformer, the power switching device being connected to the isolation transformer, and the charger controller being connected to and controlling the turn-on and turn-off of the power switching device; a battery pack, whose positive and negative electrodes are respectively connected to the output end of the charger; a battery pack temperature sensor located inside the battery pack, connected to the charger controller, and configured to detect the temperature of the battery pack in real time and transmit it to the charger controller; a charging current sensor connected to the charger controller and connected in series to the positive electrode of the battery pack, and configured to detect the charging current of the battery pack and transmit it to the charger controller; a charger output voltage sensor connected to the charger controller and connected in parallel to the output end of the charger, and configured to detect the charging voltage of the battery pack and transmit it to the charger controller; An input voltage sensor is connected to the charger controller and is connected in parallel with the input of the charger and is configured to detect the input voltage of the charger and transmit to the charger controller; The charger controller is configured to control the high-frequency turn-on and turn-off of the power switch device in the charger, set a circuit parameter threshold, determine the current power supply system to be a direct current power supply system or an alternating current power supply system according to the input voltage, and adjust the charging current and the charging voltage output by the charger to the battery pack according to the current power supply system, the circuit parameter threshold, the real-time detected charging current and the charging voltage.

[0007] In some embodiments, the charger includes two charger power modules, the inputs of the two charger power modules are connected in series to share the high-voltage power input by the train power supply network, and the outputs of the two power modules are connected in parallel and connected to the battery pack.

[0008] In some embodiments, the battery pack includes a plurality of batteries, and the power supply box further includes: A battery management module is connected to the battery pack and includes a plurality of monitoring units, each of which monitors the current, voltage and temperature of one of the batteries in real time.

[0009] In a second aspect, the embodiments of the present application provide a control method of a power supply box, which is adapted to direct current power supply system and alternating current power supply system and is used for controlling the above-mentioned power supply box. The circuit parameter threshold includes a first threshold, a second threshold, a third threshold, a fourth threshold and a fifth threshold. The control method includes: A constant current fast charging step is used to determine the current power supply system to be a direct current power supply system or an alternating current power supply system according to the input voltage. Real-time monitoring of first circuit data and second circuit data in the circuit; when the first circuit data is the charging current, the second circuit data is the charging voltage, and when the first circuit data is the charging voltage, the second circuit data is the charging current; The first threshold and the second threshold are set, and the first circuit data output by the charger to the battery pack is adjusted to tend to the first threshold. In the adjustment process, it is determined whether the second circuit data reaches the second threshold. If yes, the next step is entered. A constant voltage fast charging step is used to adjust the switching frequency of the power switch device in the charger according to the current power supply system, maintain the second circuit data to tend to the second threshold, set the third threshold, and when the first circuit data reaches the third threshold and maintains for a preset time, the next step is entered. The floating step sets the fourth threshold value and the fifth threshold value, adjusts the first circuit data to tend to the fourth threshold value, and judges whether the second circuit data reaches the fifth threshold value during the adjustment. If yes, the charging of the battery pack is completed.

[0010] In some embodiments, when it is judged that the current power supply system is an AC power supply system, the first circuit data is the charging current, and the second circuit data is the charging voltage; the first threshold value comprises a first preset current value; the second threshold value comprises a first reading voltage value; the constant current fast charging step further comprises: The temperature, the charging current and the charging voltage of the battery pack are collected in real time, the first preset current value is set, the deviation between the charging current and the first preset current value is calculated, and the charging current output by the charger to the battery pack is adjusted through proportional and integral operation until the charging voltage reaches a first reading voltage value obtained according to the temperature of the battery pack and a temperature compensation curve, and the constant voltage fast charging step is entered.

[0011] In some embodiments, the third threshold value comprises a second preset current value; the constant voltage fast charging step further comprises: The switching frequency of the power switching device in the charger is set at a first working frequency; The charging voltage is maintained to tend to the first reading voltage value, the second preset current value is set, and when the charging current reaches the second preset current value and is maintained for a preset time, the floating step is entered.

[0012] In some embodiments, the fourth threshold value comprises a third preset current value; the fifth threshold value comprises a second reading voltage value; the floating step further comprises: The third preset current value is set, the deviation between the charging current and the third preset current value is calculated, and the charging current output by the charger to the battery pack is adjusted through proportional and integral operation until the charging voltage reaches the second reading voltage value obtained according to the temperature of the battery pack and a temperature compensation curve, the charging voltage is maintained to tend to the second reading voltage value, and the charging of the battery pack is completed.

[0013] In some embodiments, when it is judged that the current power supply system is a DC power supply system, the first circuit data is the charging current, and the second circuit data is the charging voltage; the first threshold value further comprises a fourth preset current value; the second threshold value further comprises a third reading voltage value; the constant current fast charging step further comprises: acquire the temperature, the charging voltage and the charging current of the battery pack in real time, control the charging current outputted by the charger to the battery pack to be lower than or equal to the fourth preset current value; set the initial voltage of the battery pack as an initial value of a voltage calculation target value, increase the voltage calculation target value, calculate the deviation between the charging voltage and the voltage calculation target value, and adjust the charging voltage outputted by the charger to the battery pack through proportional and integral calculation; In the adjusting process, the voltage calculation target value is increased to a third reading voltage value obtained according to the temperature of the battery pack and a temperature compensation curve, and the constant voltage fast charging step is entered.

[0014] In some embodiments, the third threshold value further includes a fifth preset current value; and the constant voltage fast charging step further includes: setting the switching frequency of the power switching device in the charger to be at a second working frequency, and setting the fifth preset current value; controlling the charging voltage outputted by the charger to the battery pack to be maintained at the third reading voltage value obtained according to the temperature of the battery pack and the temperature compensation curve until the charging current acquired in real time is less than the fifth preset current value and is maintained for a preset time, and entering the floating charging step.

[0015] In some embodiments, the first circuit data is changed to the charging voltage, and the second circuit data is changed to the charging current; the fourth threshold value further includes a fourth reading voltage, the fifth threshold value further includes a sixth preset current value, and the floating charging step further includes: adjusting the charging voltage outputted by the charger to the battery pack to tend to a fourth reading voltage value obtained according to the temperature of the battery pack and the temperature compensation curve, and judging whether the charging current is reduced and tends to a sixth preset current value in the adjusting process; if yes, maintaining the charging voltage at the fifth reading voltage, and the battery pack is charged to be completed.

[0016] Compared with the related art, the power box and the control method thereof provided by the embodiments of the present application gradually adjust the charging current and the charging voltage outputted by the charger to the battery pack, solve the problem that the current outputted by the charger fluctuates and causes the battery to be damaged, and achieve the effect of suppressing the fluctuation of the charging current.

[0017] Details of one or more embodiments of the present application are presented in the following drawings and description to make other features, objects and advantages of the present application more clear and simple. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings: Figure 1 is a circuit topology diagram of a power supply box according to an embodiment of the application; Figure 2 is a flow chart of a charging step of a battery pack of a power supply box according to an embodiment of the application; Figure 3 is a flow chart in a direct current power supply mode in a control method of a power supply box according to an embodiment of the application; Figure 4 is a flow chart in an alternating current power supply mode in a control method of a power supply box according to an embodiment of the application; Figure 5 is a PI control algorithm schematic diagram in a direct current power supply mode in a control method of a power supply box according to an embodiment of the application; Figure 6 is a PI control algorithm schematic diagram in an alternating current power supply mode in a control method of a power supply box according to an embodiment of the application.

[0019] in the drawings: 101, input interface; 102, pre-charge resistor; 103, short-circuit contactor; 104, second power supply module; 105, input filter; 106, input current sensor; 107, input voltage sensor; 108, DC filter reactor; 109, charger power module; 110, charger output current sensor; 111, charger output voltage sensor; 112, output filter; 113, DC 110V bus insulation detection device; 114, charging current sensor; 115, battery pack; 116, battery management module; 117, adjustable digital display relay; 118, output contactor; 119, anti-reverse diode; 120, first power supply module; 121, output interface; 1091, module input voltage sensor; 1092, first voltage-sharing resistor; 1093, second voltage-sharing resistor; 1094, first voltage-sharing capacitor; 1095, second voltage-sharing capacitor; 1096, first switch tube; 1097, second switch tube; 1098, transformer primary current sensor; 1099, isolation transformer; 10910, first rectifier diode; 10911, second rectifier diode; 10912, third rectifier diode; 10913, fourth rectifier diode; 10914, output filter reactor; 10915, filter capacitor; 10916, discharge resistor. DETAILED DESCRIPTION

[0020] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.

[0021] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can also be applied to other similar scenarios without creative effort based on the accompanying drawings. In addition, it can be understood that although the efforts made in the development process can be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacture or production changes based on the technical content disclosed in the present application are only routine technical means, and should not be understood as insufficient disclosure of the content disclosed in the present application.

[0022] In the present application, "embodiments" means that the specific features, structures or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it mutually exclusive or alternative embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0023] Unless otherwise defined, technical terms and scientific terms used in the present application shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terms "a", "an", "one", "this", and similar referents in the context of describing the application are to be construed to be inclusive, not exclusive. For example, the use of the term "comprises" or "comprising" or "includes" or "including" or "has" or "having" or "contains" or "containing" or "consists" or "consisting" or "consists of" or "consisting of" to describe certain processes, methods, systems, products, or devices does not limit the described processes, methods, systems, products, or devices to the listed steps or elements, but rather includes the possibility of other steps or elements not listed, or other processes, methods, systems, products, or devices inherently having the listed steps or elements. The use of the term "connected" or "coupled" or similar terms in the context of this application are not intended to be limited to a direct connection or coupling, but can include an indirect connection or coupling, whether directly or indirectly. The term "plurality" means two or more. The term "and / or" describes associated objects in association relationships, which means that there are three relationships, for example, "A and / or B" can mean that A exists alone, A and B exist together, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects. The terms "first", "second", "third", and the like are merely used to distinguish similar objects, and do not represent a specific order for the objects.

[0024] Based on the national initiative and planning of cross-border intermodal transportation, the business full industry chain of one core and three poles, and the internationalization of going out, the rail transit train should realize cross-border operation under different power supply systems in different countries without lowering the bow, stopping, one car direct, and zero transfer.

[0025] Due to the differences in environment, operation demand and cost of each country, the current international power supply system is mainly divided into four power supply systems, including 25kV and 50 / 60Hz AC power supply system, 1500V DC power supply system, 3000V DC power supply system, and 15kV and 16.7Hz AC power supply system. In view of the different power supply systems in different countries, combined with the development direction of four-network integration of rail transit and the requirement of national initiative, in recent years, domestic double-flow rail transit train has emerged as the times require, such as high-speed train under the voltage of 25kV and 50 / 60Hz AC power supply system in domestic suburban railway and 1500V DC power supply system in urban subway, without stopping and switching and running, which fundamentally solves the through operation of domestic suburban railway and urban subway, and provides a basis for the development of multi-flow train and technology.

[0026] The traditional charger system on the rail transit train can only work under a single power supply mode. The power supply mode of the urban subway is DC 1500V without periodic fluctuation, which can be directly used as the input of the charger system. The charger uses the traditional voltage loop closed-loop control output in the three battery charging stages, and the output voltage and charging current fluctuation meet the requirements. However, the power supply mode of the suburban railway is an AC power supply mode with a voltage of 25kV and a frequency of 50 / 60Hz. After being stepped down by the traction transformer and output by the four-quadrant rectifier in the traction converter, it is DC 1800V with 100Hz periodic fluctuation. Due to the existence of the fluctuation, if the traditional voltage loop closed-loop control of the urban subway charger is used, the output voltage and charging current fluctuation of the charger will be abnormally increased. At present, the solution is to set a DC / AC converter between the four-quadrant rectifier circuit of the suburban railway and the charger system, convert the periodically fluctuating DC 1800V into stable AC 380V with low harmonic content, and supply it as the power input of the charger. Thus, the charging current fluctuation meets the requirements. At present, the trains in China basically use the above two different charger operation schemes under two power supply modes, and a single charger cannot be used universally under different power supply modes.

[0027] The main reason why the traditional single charger cannot be used universally under two power supply modes is that the traditional voltage loop closed-loop control cannot suppress the influence of the 100Hz inherent fluctuation of the DC input of the charger.

[0028] To solve the above problems, the application provides a power supply box and a control method thereof, which significantly reduces the charging current fluctuation of the battery pack 115 by adjusting the charging control strategy of the charger module to the battery pack 115.

[0029] As shown in Figure 1 The embodiment of the application provides a power supply box which is suitable for DC power supply mode and AC power supply mode at the same time, the power supply box is connected with a train power supply network, and comprises: An input interface 101 is connected with the train power supply network.

[0030] A charger and a charger controller, the charger comprises an input end and an output end, and is internally provided with a power switching device and an isolation transformer 1099, the power switching device is connected with the isolation transformer 1099, and the charger controller is connected with and controls the turn-on and turn-off of the power switching device.

[0031] The charger provides low-voltage 110V DC power for the train.

[0032] A battery pack 115 comprises a positive electrode and a negative electrode, and the positive electrode and the negative electrode are connected with the positive bus and the negative bus of the output end of the charger respectively.

[0033] When the train is not under high voltage, the DC 110V battery pack 115 with a capacity of 180Ah can provide DC 110V low-voltage backup power for the train.

[0034] Specifically, the charger and the battery pack 115 are in different cavities in the power supply box, and the cable between them is short. The reduced cable loss and voltage drop on the cable make the charging efficiency of the battery pack 115 higher.

[0035] The battery pack temperature sensor is located inside the battery pack 115 and is connected to the charger controller. It is configured to detect the temperature of the battery pack 115 in real time and transmit it to the charger controller.

[0036] The charging current sensor 114 is connected to the charger controller and is connected in series to the positive electrode of the battery pack 115. It is configured to detect the charging current of the battery pack 115 and transmit it to the charger controller.

[0037] The input voltage sensor 107 is connected to the charger controller and is connected in parallel to the input end of the charger. It is configured to detect the input voltage of the charger and transmit it to the charger controller.

[0038] The input current sensor 106 is connected to the charger controller and is connected in series between the train power supply network and the input end of the charger. It is configured to detect the input current of the charger and transmit it to the charger controller.

[0039] The charger output voltage sensor 111 is connected to the charger controller and is connected in parallel to the output end of the charger. It is configured to detect the charging voltage of the battery pack 115 and transmit it to the charger controller.

[0040] The charger output current sensor 110 is connected to the charger controller and is connected in series to the positive electrode of the battery pack 115. It is configured to detect the charging current of the battery pack 115 and transmit it to the charger controller.

[0041] The output interface 121 is connected to the train load through the output interface 121 by the charger and the battery pack 115.

[0042] During the charging process of the charger to the battery pack 115, the charger controller contains a new type of control software. The software can configure the switching frequency of the power switch device, set the circuit parameter threshold, and control the high-frequency turn-on and turn-off of the power switch device in the charger. According to the input voltage, it is determined that the current power supply system is a direct current power supply system or an alternating current power supply system. According to the current power supply system, the circuit parameter threshold, the real-time detected charging current and charging voltage, the charging current and charging voltage output by the charger to the battery pack are adjusted.

[0043] The power box can simultaneously adapt to direct current and alternating current two train power supply systems, without the need to design a power box for different power supply systems, thereby significantly improving the universality and adaptability of the power box. The charger controller dynamically adjusts the on-off of the power switch device in combination with the input voltage, the battery charging voltage and the charging current, so as to accurately control the charging current and voltage, ensure the stability and safety of the battery charging process, and prolong the service life of the battery.

[0044] In some embodiments, the charger further comprises: The half-bridge inverter circuit is connected to the input end of the charger and is configured to receive high-voltage power input by the train power supply network through the input interface 101 and convert the high-voltage power into pulsed alternating current.

[0045] The voltage value of the high-voltage power is DC 1500V and DC 1800V.

[0046] The half-bridge inverter circuit includes a power switch device and a voltage-sharing capacitor. The power switch device includes a first switch tube 1096 and a second switch tube 1097. The voltage-sharing capacitor includes a first voltage-sharing capacitor 1094 and a second voltage-sharing capacitor 1095.

[0047] The isolation transformer 1099 is connected to the half-bridge inverter circuit and is configured to isolate and step down the pulsed alternating current, convert the pulsed alternating current into low-voltage pulsed alternating current, and complete the isolation and step-down.

[0048] The full-bridge rectifier circuit is connected to the isolation transformer 1099 and is configured to rectify the low-voltage pulsed alternating current to generate pulsed direct current.

[0049] Specifically, the secondary side of the isolation transformer is connected to the full-bridge rectifier circuit, and the primary side is connected to the half-bridge inverter circuit, The full-bridge rectifier circuit includes a first rectifier diode 10910, a second rectifier diode 10911, a third rectifier diode 10912, and a fourth rectifier diode 10913.

[0050] The filter unit is connected to the full-bridge rectifier circuit and is configured to filter the pulsed direct current to generate a direct current voltage and output to the battery pack 115.

[0051] The filter unit includes an output filter reactor 10914 and a filter capacitor 10915.

[0052] The high-voltage power input by the train power supply network is stably converted into low-voltage direct current suitable for the battery pack 115. The conversion process realizes electrical isolation between high-voltage and low-voltage, improves system safety, and at the same time, the filter unit effectively reduces the output voltage ripple to ensure the quality of the charging voltage.

[0053] In some embodiments, the charger includes two identical charger power modules 109, the inputs of the two charger power modules 109 are connected in series, each power module includes a module input voltage sensor 1091, and the high voltage of the train power supply network is evenly divided through the input interface 101 to achieve power division and control.

[0054] The inputs of the two charger power modules 109 are connected in series, which can evenly distribute the high voltage of the train power supply network, and each charger power module 109 only needs to withstand half of the input high voltage, which reduces the requirement for the high voltage resistance of the single module, prolongs the service life of the module, and reduces the cost of hardware selection.

[0055] The outputs of the two charger power modules 109 are connected in parallel, which adds the DC voltage output of the two modules, improves the total power and current output capability of charging the battery pack 115, and can adapt to a larger capacity battery pack 115. At the same time, the parallel structure enhances the stability of the output, and when a single module fails, the other module can partially undertake the power supply task, improving the power supply redundancy.

[0056] Each charger power module 109 is also provided with a module input voltage sensor 1091, a first voltage balancing resistor 1092, a second voltage balancing resistor 1093, a transformer primary current sensor 1098, and a discharge resistor 10916.

[0057] In some embodiments, the power supply box further includes: A pre-charge resistor 102 is located between the input interface 101 and the charger.

[0058] A short-circuit contactor 103 is located between the input interface 101 and the charger, and is connected in parallel with the pre-charge resistor 102.

[0059] At the initial stage of starting the power supply box, the pre-charge resistor 102 is connected in series in the circuit to limit the initial current flowing into the charger, preventing excessive impact current caused by instantaneous charging of capacitors and other components from damaging the charger, input interface 101 and other hardware components.

[0060] When the circuit is pre-charged, the short-circuit contactor 103 is closed to bypass the pre-charge resistor 102, avoiding the power loss caused by the resistor being connected in series for a long time, and ensuring that the charger obtains stable input voltage and current when working normally, while considering the safety of starting and the efficiency of operation.

[0061] In some embodiments, the power box further comprises an input filter 105 between the pre-charge resistor 102 and the charger, for electromagnetic filtering of high-voltage electricity entering the input filter 105.

[0062] In some embodiments, the power box further comprises a DC filter reactor 108 between the input filter 105 and the charger, for current filtering of high-voltage electricity.

[0063] In some embodiments, the power box further comprises one or more first power modules 120, one end of which is connected to the battery pack 115, and the other end of which is connected to the train load through an output interface 121.

[0064] Further, the power box can be provided with two 600W 110V-to-24V first power modules 120 to supply power to the DC 24V load of the train.

[0065] The first power module 120 can convert 110V voltage to 24V voltage. Through the first power module 120, the 110V voltage of the battery pack 115 is converted to the 24V voltage required by the low-voltage load of the train, and the train does not need to be additionally configured with a separate power supply, thereby expanding the output voltage type of the power box and meeting the power supply needs of different loads of the train.

[0066] In some embodiments, the power box further comprises: a second power module 104, one end of which is connected to the input interface 101, and the other end of which is connected to the charger controller.

[0067] When the battery pack 115 is fed, the second power module 104 is directly connected to the input interface 101 and supplies power to the charger controller, ensuring that the charger controller is started first and enters a working state, guaranteeing the normal start of the charger and the initialization of the charging process, so that the charger can normally supply power to the battery pack 115.

[0068] In some embodiments, the battery pack 115 comprises a plurality of batteries, and further comprises: a battery management module 116 connected to the battery pack 115, comprising a plurality of monitoring units, each of which monitors the current, voltage and temperature of one battery in real time, and the monitoring unit can be configured as a battery voltage sensor and a battery current sensor.

[0069] The battery management module 116 can be connected to the driver screen of the train, so as to ensure that the state of the battery is normal. When the battery is abnormal, the state is transmitted to the driver screen in real time.

[0070] The battery management module 116 collects the voltage, current and temperature parameters of the battery in real time through the built-in sensor, realizes fine monitoring of the state of the battery pack 115, is used for evaluating whether the battery pack 115 is healthy, and transmits each state to the train control system and the charger through the network system, so as to find the battery fault in time and avoid the fault diffusion to affect the performance of the entire battery pack.

[0071] The battery pack 115 includes 54 batteries.

[0072] In some embodiments, the power box further includes a plurality of fan assemblies for dissipating heat of the two charger modules 109 and power devices such as the electric reactor in the power box.

[0073] In some embodiments, the power box further includes a train DC 110V bus insulation detection device 113 located between the output end of the charger and the battery pack 115, and used for detecting whether the positive and negative DC 110V buses of the train are grounded.

[0074] In some embodiments, the power box further includes an output filter 112 located between the DC 110V bus insulation detection device 113 and the output end of the charger, and used for performing electromagnetic filtering on the DC 110V direct current output by the charger.

[0075] In some embodiments, the power box further includes an anti-reverse diode 119, a load output contactor 118 and an adjustable digital display relay 117, which are all located between the output end of the charger and the output interface 121.

[0076] The dual-current train needs to integrate two sets of devices suitable for alternating current and direct current power supply systems. In order to maintain the weight of the train and reasonably plan the layout of the devices, the related power supply devices on the train need to have the characteristics of lightweight, miniaturization, high integration and high power density.

[0077] The traditional train low-voltage power supply device is independent of the box, the device is heavy, is distributed in various places of the train, the wiring cable is long, the space layout of the train is compact and complex, and the vehicle maintainability is poor. Compared with the traditional train device, the power box of the present application can not only work normally on the dual-current train, but also integrates the charger, the DC 110V battery pack 115, the battery management module 116, the DC 110V bus insulation detection device 113, the first power module 120, the second power module 104, the adjustable digital display relay 117 and its control circuit, etc. The hardware integration degree is greatly improved, the structure is simplified and the fault points are reduced, the maintainability of the vehicle low-voltage power supply device is greatly improved, and the lightweight, miniaturization and high integration requirements are met.

[0078] In actual application, the operation steps of the power box under the direct current power supply system and the alternating current power supply system include: The high voltage electricity under two power supply modes is input to the power supply box through the input port of the power supply box, is charged to multiple voltage equalizing capacitors in the charger through pre-charging resistor 102 and short-circuit contactor 103, and is subjected to electromagnetic filtering through input filter 105, voltage and current collection through input voltage sensor 107 and input current sensor 106. In addition, the input voltage also supplies power to second power module 104, which can complete conversion of DC 1800V or DC 1500V to DC 110V and supply power to the charger controller. When the battery pack 115 is fed, the charger controller cannot work normally. At this time, the DC 110V output by second power module 104 can complete power supply to the charger controller, so that the charger can normally supply power to the battery pack 115. At the same time, the current is also filtered through DC filter reactor 108.

[0079] The voltage output by DC filter reactor 108 is input into the charger. There are two completely same charger power modules 109, each of which has a power of 15kW. The two charger power modules 109 are connected in series at the input end and are connected in parallel at the output end. The series connection of the input end can make the input voltage of each charger power module 109 become half of DC 1500V / DC 1800V, i.e. DC 750V / DC 900V. The input voltage is subjected to a half-bridge inverter circuit to generate a periodic positive-negative alternating pulse voltage waveform, is subjected to isolation and voltage reduction through isolation transformer 1099, is subjected to rectification through a full-bridge rectifier circuit, is subjected to filtering through output filter reactor 10914 and filter capacitor 10915, and finally obtains a stable DC 110V voltage with small fluctuations. Subsequently, the DC 110V voltage is output by charger power module 109. The parallel connection of the two modules at the output end can obtain an output power of 30kW.

[0080] The DC 110V voltage output in parallel can collect the charging voltage and charging current through charger output voltage sensor 111 and charger output current sensor 110, is subjected to electromagnetic filtering through output filter 112, is subjected to detection of whether the positive and negative busbars are grounded through DC 110V busbar insulation detection device 113, is introduced into battery pack 115 through a cavity gland, charges battery pack 115, and collects the charging current through charging current sensor 114. At the same time, battery management module 116 monitors the state of each single battery in battery pack 115 in real time, evaluates whether battery pack 115 is healthy, and transmits each state to the train control system and the charger controller through a network system.

[0081] The output end of the charger is connected with the output end of the battery pack 115 through the anti-reverse diode 119 and the load output contactor 118, and outputs through the output interface 121 to supply power to the DC 110V load of the train. Meanwhile, the first power module 120 generates a DC 24V voltage, which is also output through the output interface 121 to supply power to the DC 24V load of the train.

[0082] When the battery pack 115 is fed, that is, the voltage is less than DC 92V, the adjustable digital display relay 117 contact is disconnected, causing the load output contactor 118 coil to lose power, and the main contact of the load output contactor 118 is disconnected, so that the battery pack 115 and the charger do not supply power to the load output of the train. In this working condition, the charger only charges the battery pack 115, and when the battery pack 115 is charged to a non-feed state, that is, the voltage of the battery pack 115 is greater than 105V, the load output contactor 118 is re-closed, and the charger or the battery pack 115 starts to supply power to the low-voltage train load.

[0083] The embodiment of the application also provides a control method of the power supply box, which is suitable for DC power supply system and AC power supply system, and is used for controlling the power supply box. Figure 2 As shown in the figure, the circuit parameter threshold value includes a first threshold value, a second threshold value, a third threshold value, a fourth threshold value and a fifth threshold value, and the control method includes: The constant current fast charging step S201 is to determine the current power supply system as the DC power supply system or the AC power supply system according to the input voltage. The first circuit data and the second circuit data in the real-time monitoring circuit are monitored. When the first circuit data is the charging current and the second circuit data is the charging voltage, or when the first circuit data is the charging voltage and the second circuit data is the charging current. The first threshold value and the second threshold value are set, and the first circuit data output by the charger to the battery pack 115 is adjusted to tend to the first threshold value. In the adjustment process, it is judged whether the second circuit data reaches the second threshold value, and if so, the next step is entered.

[0084] The constant voltage fast charging step S202 is to adjust the switching frequency of the power switching device in the charger according to the current power supply system, maintain the second circuit data to tend to the second threshold value, set the third threshold value, and when the first circuit data reaches the third threshold value and maintains for a preset time, the next step is entered.

[0085] The floating step S203 is to set the fourth threshold value and the fifth threshold value, and adjust the first circuit data to tend to the fourth threshold value. In the adjustment process, it is judged whether the second circuit data reaches the fifth threshold value, and if so, the charging of the battery pack 115 is completed.

[0086] By collecting temperature, current, voltage parameters, combining preset current value for proportional integral operation, forming closed loop control, ensuring that current and voltage always track target value during charging process, and adjusting switching frequency of power switching device, parameter fluctuation affecting charging quality is avoided, and charging demand of storage battery under different states is adapted.

[0087] Through the control method of the power supply box, the charger can work normally under the DC 1500V and AC 25kV two power supply systems, and the output voltage and charging current fluctuation is suppressed, the storage battery pack 115 is safely and quickly charged and floated, and the DC 110V low-voltage load of the train is powered.

[0088] In some embodiments, when it is judged that the current power supply system is an alternating current power supply system, the first circuit data is the charging current, the second circuit data is the charging voltage, the first threshold value includes a first preset current value, the second threshold value includes a first reading voltage value, and the constant current fast charging step S201 further includes: The temperature, charging current and charging voltage of the storage battery pack 115 are collected in real time, the first preset current value is set, the deviation of the charging current and the first preset current value is calculated, and the charging current output by the charger to the storage battery pack 115 is adjusted through proportional and integral operation, until the charging voltage reaches the first reading voltage value obtained according to the temperature of the current storage battery pack 115 and the temperature compensation curve, and the constant voltage fast charging step S202 is entered.

[0089] The first preset current value can be set to 35A.

[0090] Under alternating current power supply, the charging current is gradually increased through proportional and integral operation, so that the charging current fluctuation is avoided to be too large and affect the battery health of the storage battery pack.

[0091] In some embodiments, the third threshold value includes a second preset current value. The constant voltage fast charging step S202 further includes: The switching frequency of the power switching device in the charger is set to a first working frequency.

[0092] The charging voltage tends to the first reading voltage value, the second preset current value is set, when the charging current reaches the second preset current value and maintains for a preset time, the floating step S203 is entered.

[0093] The second preset current value can be set to 8.5A.

[0094] The preset time can be set to 5s.

[0095] The switching frequency of the power switching device in the charger is a key factor for the charger to stably convert alternating current into direct current, and by controlling the switching frequency of the power switching device, the current stability can be effectively maintained and the current fluctuation can be reduced.

[0096] In some embodiments, the fourth threshold value includes a third preset current value, the fifth threshold value includes a second reading voltage value, and the floating step S203 further includes: The third preset current value is set, the deviation between the charging current and the third preset current value is calculated, and the charging current output by the charger to the battery pack 115 is adjusted through proportional and integral operation until the charging voltage reaches the second reading voltage value obtained according to the current temperature of the battery pack 115 and the temperature compensation curve, the charging voltage tends to the second reading voltage value, and the charging of the battery pack 115 is completed.

[0097] The third preset current value can be set to 2A or 0.2A.

[0098] The condition of the battery pack being fully charged is determined, which facilitates the power box to accurately determine the current charging state. When the battery pack is fully charged, the full charge state of the battery pack is maintained, and when the train load needs to be powered, the battery pack can quickly respond to power supply, thereby maintaining stable operation of the train.

[0099] In some embodiments, when it is determined that the current power supply system is a direct current power supply system, the first circuit data is a charging current, the second circuit data is a charging voltage, the first threshold value further includes a fourth preset current value, the second threshold value further includes a third reading voltage value, and the constant current fast charging step S201 further includes: The temperature, charging voltage and charging current of the battery pack 115 are collected in real time, and the charging current output by the charger to the battery pack 115 is controlled to be lower than or equal to the fourth preset current value.

[0100] The initial voltage of the battery pack 115 is taken as an initial value of the voltage operation target value, and thereafter the voltage operation target value is adjusted to be constantly and slowly increased, the deviation between the charging voltage and the voltage operation target value is calculated, and the charging voltage output by the charger to the battery pack 115 is adjusted through proportional and integral operation.

[0101] During the adjustment process, the voltage operation target value is gradually increased to a third reading voltage value obtained according to the current temperature of the battery pack 115 and the temperature compensation curve, and the constant voltage fast charging step S202 is entered. By limiting the maximum charging current, dynamically increasing the voltage operation target value, and combining proportional and integral adjustment, smooth starting and charging voltage rise under direct current high voltage input are realized, and current and voltage mutations caused by direct current power supply characteristics are avoided.

[0102] In some embodiments, the third threshold value includes a fifth preset current value, and the constant voltage fast charging step S202 further includes: The switching frequency of the power switching device in the charger is set to a second working frequency, and the fifth preset current value is set.

[0103] The charging voltage outputted by the charger to the battery pack 115 is kept at the third reading voltage value obtained according to the current temperature of the battery pack 115 and the temperature compensation curve until the real-time collected charging current is less than the fifth preset current value and is maintained for a preset time, and the floating charging step S303 is entered.

[0104] The second working frequency is less than the first working frequency.

[0105] Further, the second working frequency can be set to 10 kHz, and the first working frequency can be set to 15 kHz.

[0106] In the case of direct current power supply, the switching frequency of the adaptive power switching device is adjusted, the charging current in the real-time detection circuit is detected in real time, the charging state of the battery pack can be fed back in time, the next charging phase is entered in time, and the charging stability and efficiency of the battery pack are improved.

[0107] In some embodiments, the first circuit data is changed to the charging voltage, the second circuit data is changed to the charging current, the fourth threshold further includes a fourth reading voltage value, the fifth threshold further includes a sixth preset current value, and the floating charging step S203 further includes: The charging voltage outputted by the charger to the battery pack 115 is adjusted to the fourth reading voltage value obtained according to the current temperature of the battery pack 115 and the temperature compensation curve, and in the adjustment process, it is determined whether the charging current is reduced to the sixth preset current value and maintained for a preset time. If yes, the charging voltage is maintained at the fourth reading voltage value, and the charging of the battery pack 115 is completed.

[0108] The sixth preset current value is 1A.

[0109] The floating charging step S203 is optimized for the direct current power supply system. By adjusting the charging voltage to the fourth reading voltage value adaptive to the direct current scene, it is ensured that the battery pack 115 completes the floating charging and the charging current tends to zero under the condition of stable output of the direct current power supply, overcharging is avoided, and the battery is kept in a full-power standby state.

[0110] In actual application, the control method of the battery box can automatically switch the corresponding operation steps according to the power supply system. For example, Figure 3 As shown in the figure, when the battery box detects the start signal sent by the train network system and the input voltage sensor 107 detects that the input voltage is greater than 1000V, and detects that the train network system is in the direct current power supply system, the power supply box automatically switches to the control method of the direct current power supply system, and the charger controller sends a pulse signal to the power switching device to make the power switching device high-frequency switch.

[0111] PI operation is to continuously compare the measured value of the controlled object with the target value, calculate the deviation between the two, and then adjust the controlled object through the combination operation of the proportional and integral links, so that the actual output of the controlled object is finally stabilized at the target value.

[0112] In the constant current fast charging step S201, the charging current collected by the charging current sensor 114 is 35A, and the charging voltage collected by the charging voltage sensor 111 is used as the PI operation measurement value and the initial target value of the PI operation. During the PI operation process, the PI operation target value is continuously increased, and after a certain time, it is increased to the voltage corresponding to the temperature of the current battery pack 115 in the temperature compensation curve, which is used as the fast charging target voltage, and then the constant voltage fast charging step S202 is entered.

[0113] In the constant voltage fast charging step S202, the PI operation target value is limited to the fast charging target voltage, so the charging voltage is constant, and the charging current continuously decreases as the power of the battery pack 115 increases. When the charging current decreases to less than 8.5A and lasts for 5s, it enters the floating charging step S203.

[0114] In the floating charging step S203, the voltage corresponding to the temperature of the current battery pack 115 in the temperature compensation curve is used as the floating charging target voltage, and the PI operation target value is limited to the fixed floating charging target voltage. Therefore, the charging voltage is constant around the floating charging target voltage, and the charging current continuously decreases to about 1A. The charging of the battery pack 115 is completed, and the charger maintains the floating charging target voltage output thereafter.

[0115] As shown in FIG. 1, Figure 5 In the DC power supply mode, one charger power module 109 is used to adjust the charging voltage to complete the output voltage closed-loop control, and the other charger power module 109 is used to adjust the input voltage at the input end to complete the voltage equalization closed-loop control.

[0116] Specifically, for the voltage equalization closed-loop control, the charger controller collects the input voltages detected by the module input voltage sensors 1091 in the two charger power modules 109. The first input voltage detected by the module input voltage sensor 1091 in one charger power module 109 is denoted as , and the first input voltage detected by the module input voltage sensor 1091 in the other charger power module 109 is denoted as .

[0117] According to the calculation formulas , and , the error value of the current calculation period in the voltage equalization closed-loop control is calculated.

[0118] Further, according to the calculation formula and , the integral sum of the current calculation period in the voltage equalization closed loop control is calculated .

[0119] wherein, is the integral coefficient in the voltage equalization closed loop control, is the integral sum of all periods before the current calculation period in the voltage equalization closed loop control.

[0120] Further, by PI operation, according to , the input voltage series voltage equalization PI operation output value of the current calculation period is calculated . Wherein, is the proportional coefficient.

[0121] For the output voltage closed loop control, the charger controller collects the output voltage detected by the charger output voltage sensor 111, and sets the target voltage , wherein the battery voltage at the initial start of the charger is taken as the initial value of the target voltage, and in the charging process, the target voltage is constantly raised to the voltage value determined according to the temperature of the battery pack 115 and the temperature compensation curve.

[0122] According to , the error value of the current calculation period in the output voltage closed loop control is obtained.

[0123] According to , the integral sum of the current calculation period in the output voltage closed loop control is calculated . Wherein, is the integral coefficient in the output voltage closed loop control, is the integral sum of all periods before the current calculation period in the output voltage closed loop control.

[0124] By PI operation, according to , the output value of the PI operation of the current calculation period in the output voltage closed loop control is obtained . Wherein, is the proportional coefficient in the output voltage closed loop control.

[0125] According to and , the first switch tube 1096 and the second switch tube 1097 in a charger power module 109 can be controlled to be turned on and off at high frequency to complete the input voltage equalization closed loop regulation, so that the input voltages of the two series connected charger power modules 109 are basically the same, both being DC 750V.

[0126] Specifically, and The comparison value is input into the PWM generator and compared with the triangular wave to obtain PWM pulses for controlling the first switch tube 1096 and the second switch tube 1097 in the other charger power module 109.

[0127] According to With , the first switch tube 1096 and the second switch tube 1097 in the other charger power module 109 are high-frequency turned on and off to complete output voltage closed-loop regulation and realize stable output of the output voltage to the battery pack 115.

[0128] Specifically, the comparison value is obtained by dividing With , the comparison value is input into the PWM generator and compared with the triangular wave to obtain PWM pulses for controlling the first switch tube 1096 and the second switch tube 1097 in the other charger power module 109, and the output voltage closed-loop regulation is completed to realize stable output of the output voltage.

[0129] Since input voltage fluctuation and mutation will affect the output voltage, the PI operation is introduced in the closed-loop control , so that the output can respond in time and the fluctuation is reduced.

[0130] As shown in Figure 4 , when the power box detects the start signal from the train network and the input voltage sensor 107 detects that the input voltage is greater than 1000V, and detects that the train network system is in the AC power supply mode, the power box automatically switches to the control method of the AC power supply mode, and the charger controller sends a pulse signal to the power switch device to make the power switch device high-frequency switch.

[0131] In the constant-current fast charging step S201, the charging current collected by the charging current sensor 114 is a PI operation measurement value, and the target value of the PI operation is 35A. According to the PI operation measurement value and the target value, the charging current output by the charger to the battery pack 115 is continuously adjusted to 35A through proportional and integral operation. During the charging process, the charging voltage collected by the charger output voltage sensor 111 is continuously increased, and after a certain time, the temperature of the current battery pack 115 is increased to the voltage corresponding to the temperature compensation curve. This is taken as the fast charging target voltage, and the constant-voltage fast charging step S202 is entered.

[0132] In the constant voltage fast charging step S202, the operating frequency of the power switching device is increased to 15kHz, which can reduce the output fluctuation to a certain extent. The fixed PI calculation target value is the fast charging target voltage, and the measured value is the charging voltage value collected by the charger output voltage sensor 111. Then the charging voltage is constant, and the charging current decreases continuously as the battery pack 115 increases in charge. When the charging current decreases to less than 8.5A and lasts for 5s, the float charging step S203 is entered.

[0133] In the float charging step S203, the PI calculation target value is limited to 2A, and the measured value is the charging current value collected by the charging current sensor 114. After multiple PI calculations, the charging voltage collected by the charger output voltage sensor 111 reaches the float charging target voltage. The float charging target voltage is the voltage corresponding to the current temperature of the battery pack 115 in the temperature compensation curve. Then, the PI calculation target value is reduced to 0.2A, so that the charging voltage is basically maintained near the float charging target voltage. The battery pack 115 is fully charged, and thereafter the charger's charging voltage remains at the float charging target voltage output.

[0134] like Figure 6 As shown, under AC power supply, one charger power module 109 is used to realize closed-loop control of charging current, and another charger power module 109 is used to realize closed-loop control of output voltage equalization.

[0135] The voltage equalization closed-loop control of the output voltage under AC power supply is based on the same principle as that under DC power supply. The second input voltage detected by the module input voltage sensor 1091 in the charger power module 109 is denoted as... The second input voltage detected by the module input voltage sensor 1091 in another charger power module 109 is denoted as Further calculations , and It can obtain the output value of the voltage equalization PI calculation under AC power supply system with input voltage series connection. .

[0136] The closed-loop control of the charging current under AC power supply further includes: the charger controller acquiring the charging current measured by the charging current sensor 114. Set target current The target current is set differently in the constant current fast charging step, the constant voltage fast charging step, and the float charging step, and is set by the battery manufacturer.

[0137] The difference between the target current and the charging current is used to obtain the error value of the current calculation cycle in the charging current closed-loop control. According to... The integral of the current calculation cycle in the charging current closed-loop control is obtained. .in, This is the integral coefficient in the closed-loop control of the charging current. This is the integral sum of all cycles prior to the current calculation cycle in the charging current closed-loop control. This is the error value for the current calculation cycle in the charging current closed-loop control.

[0138] Through PI calculation, according to The PI calculation output value of the current calculation cycle in the charging current closed-loop control is obtained. .in, This is the proportional coefficient in the closed-loop control of the charging current.

[0139] The principle of controlling the first switch 1096 and the second switch 1097 is the same as that in the DC power supply system. In the AC power supply system, through... and Dividing the values ​​yields a comparison value. Based on this comparison value, the PWM pulses for the first switch 1096 and the second switch 1097 are obtained in the voltage equalization closed-loop control. and The values ​​are divided to obtain a comparison value. Based on this comparison value, the PWM pulses for the first switch 1096 and the second switch 1097 are obtained in the charging current closed-loop control. The operation of the first switch 1096 and the second switch 1097 is further controlled based on the PWM pulses.

[0140] When comparing the conventional method with the control method of this application, the suppression effect of the two methods on charging current fluctuations can be compared by comparing the waveform of the charging current during constant current fast charging. When the four-quadrant system is fully loaded, i.e., the peak-to-peak value of the 100Hz fluctuation is the largest, and the charger is fully loaded at 30kW, the charging current fluctuation can reach more than 60A when using the conventional control method, while the charging current fluctuation is reduced to 20A when using the control method of this application, the fluctuation can be reduced by about 66%, which is a significant improvement.

[0141] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0142] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A power supply box, characterized in that, Adaptable to both DC and AC power supply systems, the power supply box is connected to the train's power supply network and includes: A charger and a charger controller, wherein the charger includes a power switching device and an isolation transformer, the power switching device is connected to the isolation transformer, and the charger controller is connected to and controls the power switching device to turn on and off; The battery pack has its positive and negative terminals connected to the output terminals of the charger, respectively. A battery pack temperature sensor, located inside the battery pack and connected to the charger controller, is configured to detect the temperature of the battery pack in real time and transmit the data to the charger controller. A charging current sensor, connected to the charger controller and connected in series with the positive terminal of the battery pack, is configured to detect the charging current of the battery pack and transmit it to the charger controller. A charger output voltage sensor is connected to the charger controller and in parallel at the output terminal of the charger. It is configured to detect the charging voltage of the battery pack and transmit it to the charger controller. An input voltage sensor, connected to the charger controller and in parallel with the input terminal of the charger, is configured to detect the input voltage of the charger and transmit it to the charger controller; The charger controller is configured to control the on and off of the power switching devices in the charger; set circuit parameter thresholds; determine whether the current power supply system is DC or AC based on the input voltage; and adjust the charging current and charging voltage output by the charger to the battery pack based on the current power supply system, the circuit parameter thresholds, and the real-time detected charging current and charging voltage.

2. The power supply box according to claim 1, characterized in that, The charger includes two charger power modules. The input terminals of the two charger power modules are connected in series to share the high-voltage electricity input from the train power supply network. The output terminals of the two power modules are connected in parallel and connected to the battery pack.

3. The power supply box according to claim 1, characterized in that, The battery pack includes multiple batteries, and also includes: A battery management system is connected to the battery pack and includes multiple monitoring units, each of which monitors the current, voltage, and temperature of one of the batteries in real time.

4. A control method for a power supply box, adaptable to both DC and AC power supply systems, used to control the power supply box as described in claims 1-3, characterized in that, The circuit parameter thresholds include a first threshold, a second threshold, a third threshold, a fourth threshold, and a fifth threshold; the control method includes: In the constant current fast charging step, the current power supply mode is determined to be either DC power supply mode or AC power supply mode based on the input voltage. Real-time monitoring of first circuit data and second circuit data in the circuit; when the first circuit data is the charging current, the second circuit data is the charging voltage, and when the first circuit data is the charging voltage, the second circuit data is the charging current; Set the first threshold and the second threshold, adjust the first circuit data output by the charger to the battery pack to be closer to the first threshold, and determine whether the second circuit data reaches the second threshold during the adjustment process. If so, proceed to the next step. In the constant voltage fast charging step, the switching frequency of the power switching device in the charger is adjusted according to the current power supply system to maintain the second circuit data tending towards the second threshold. The third threshold is set. When the first circuit data reaches the third threshold and is maintained for a preset time, the next step is initiated. In the float charging step, the fourth threshold and the fifth threshold are set, and the data of the first circuit is adjusted to tend towards the fourth threshold. During the adjustment process, it is determined whether the data of the second circuit reaches the fifth threshold. If so, the battery pack is fully charged.

5. The control method for the power supply box according to claim 4, characterized in that, When it is determined that the current power supply system is AC power supply system; the first circuit data is the charging current, the second circuit data is the charging voltage; the first threshold includes a first preset current value; The second threshold includes the first read voltage value; The constant current fast charging step further includes: The temperature, charging current, and charging voltage of the battery pack are collected in real time. A first preset current value is set, the deviation between the charging current and the first preset current value is calculated, and the charging current output by the charger to the battery pack is adjusted through proportional and integral calculations until the charging voltage reaches the first reading voltage value obtained according to the current temperature of the battery pack and the temperature compensation curve, and then the constant voltage fast charging step is entered.

6. The control method for the power supply box according to claim 5, characterized in that, The third threshold includes a second preset current value; the constant voltage fast charging step further includes: The switching frequency of the power switching device in the charger is set to a first operating frequency; The charging voltage is maintained at the first read voltage value, the second preset current value is set, and when the charging current reaches the second preset current value and is maintained for a preset time, the float charging step is entered.

7. The control method for the power supply box according to claim 6, characterized in that, The fourth threshold includes a third preset current value; The fifth threshold includes the second read voltage value; The float charging step further includes: The third preset current value is set, the deviation between the charging current and the third preset current value is calculated, and the charging current output by the charger to the battery pack is adjusted through proportional and integral calculations until the charging voltage reaches the second read voltage value obtained according to the current temperature of the battery pack and the temperature compensation curve. The charging voltage is maintained at the second read voltage value, and the charging of the battery pack is completed.

8. The control method for the power supply box according to claim 4, characterized in that, When it is determined that the current power supply system is a DC power supply system, the first circuit data is the charging current, and the second circuit data is the charging voltage; The first threshold includes a fourth preset current value; The second threshold includes the third read voltage value; The constant current fast charging step further includes: The temperature, charging voltage, and charging current of the battery pack are collected in real time, and the charging current output by the charger to the battery pack is controlled to be lower than or equal to the fourth preset current value. The initial voltage of the battery pack is used as the initial value of the voltage calculation target value. The voltage calculation target value is increased, the deviation between the charging voltage and the voltage calculation target value is calculated, and the charging voltage output by the charger to the battery pack is adjusted through proportional and integral calculations. During the adjustment process, the voltage calculation target value is increased to the third read voltage value obtained based on the current temperature and temperature compensation curve of the battery pack, and then the constant voltage fast charging step is entered.

9. The control method for the power supply box according to claim 8, characterized in that, The third threshold includes a fifth preset current value; the constant voltage fast charging step further includes: Set the switching frequency of the power switching device in the charger to the second operating frequency, and set the fifth preset current value; The charging voltage output by the charger to the battery pack is maintained at the third reading voltage value obtained according to the current temperature of the battery pack and the temperature compensation curve, until the real-time collected charging current is less than the fifth preset current value, and is maintained for a preset time, and then the float charging step is entered.

10. The control method for the power supply box according to claim 9, characterized in that, The first circuit data is changed to the charging voltage, and the second circuit data is changed to the charging current; The fourth threshold includes a fourth read voltage value, the fifth threshold includes a sixth preset current value, and the float charging step further includes: The charging voltage output by the charger to the battery pack is adjusted to tend towards the fourth reading voltage value obtained according to the current temperature of the battery pack and the temperature compensation curve. During the adjustment process, it is determined whether the charging current decreases and tends towards the sixth preset current value. If so, the charging voltage is maintained at the fourth reading voltage value, and the charging of the battery pack is completed.

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