Charging control circuit and method for power lithium batteries of hybrid storage battery locomotive

Abstract

A charging control circuit and method for power lithium batteries of a hybrid storage battery locomotive. The circuit comprises a traction transformer; a primary side of the traction transformer is connected to a pantograph, and a secondary side of the traction transformer is connected to a first charging module and a second charging module; the first charging module and the second charging module are both connected to an intermediate direct-current link; the intermediate direct-current link is connected to power storage batteries and an in-depot direct-current power connector; the intermediate direct-current link is connected to two auxiliary inverters; each of the auxiliary inverters is connected to an auxiliary transformer, and the two auxiliary transformers are both connected to an in-depot alternating-current power connector. The present invention allows for power distribution of a power battery charger by calculating the power difference in real time, thereby optimizing the charging strategy.

Description

Hybrid battery locomotive power lithium battery charging control circuit and control method Technical Field

[0001] The present invention relates to the field of rail transportation technology, and in particular to a hybrid battery locomotive power lithium battery charging control circuit and control method. Background Art

[0002] At present, the commonly used charging methods for power lithium batteries are mainly catenary mode or in-depot AC380V charging mode. However, the AC380V AC power supply device in the depot is mostly used to power in-depot maintenance tools or charge existing lead-acid batteries. Due to its limited capacity, it seriously affects the charging efficiency of the lithium battery and is not suitable for the fast charging and fast discharging function of the lithium battery. Based on this situation, many users use the DC1500V DC charging device in the depot or other DC energy storage devices to quickly charge the power lithium battery, thereby shortening the charging time. Due to the different charging power supply standards and power, it is necessary to formulate a reasonable power lithium battery charging strategy to be compatible with the charging performance of the power lithium battery under different working conditions and improve the charging efficiency of the power lithium battery. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a hybrid battery locomotive power lithium battery charging control circuit and control method to improve the charging efficiency of the power battery in view of the shortcomings of the existing technology.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a hybrid battery locomotive power lithium battery charging control circuit, including a traction transformer, the primary side of the traction transformer receives a pantograph, the secondary side of the traction transformer is connected to a first rectifier module and a second rectifier module, the first rectifier module and the second rectifier module are connected to an intermediate DC link, the intermediate DC link is connected to a first charging module, a second charging module and an in-depot DC power connector, the intermediate DC link is connected to two auxiliary inverters, each of the auxiliary inverters is connected to an auxiliary transformer, and the two auxiliary transformers are both connected to the in-depot AC power connector; the first charging module and the second charging module are respectively connected to a first power battery pack and a second power battery pack.

[0005] The charging control circuit of the present invention integrates the in-depot AC power supply (the in-depot AC power connector is connected to the in-depot AC power supply), the in-depot DC power supply (the in-depot DC power connector is connected to the in-depot DC power supply), and the catenary (the pantograph is connected to the catenary). That is, the charging control circuit of the present invention can realize the in-depot AC380V charging mode, the in-depot fast charging mode and the catenary charging mode, which facilitates charging of the power battery in different modes and improves the charging efficiency of the power battery.

[0006] To facilitate switching of charging modes, the intermediate DC link is connected to the DC power connector in the depot via a fast charging mode contactor.

[0007] To facilitate switching of charging modes, the two auxiliary transformers are connected to the AC power connector in the depot via charging contactors.

[0008] As an inventive concept, the present invention also provides a hybrid battery locomotive power lithium battery charging control method, the method comprising:

[0009] Determine whether the voltage difference between the total voltage of the power battery and the charging voltage is lower than a first set value. If so, limit the charging current to M% of the predetermined charging current. When the voltage difference between the total voltage of the power battery and the charging voltage is lower than a second set value, stop charging; and / or

[0010] If the power battery cell voltage is higher than N% of the rated cell voltage and lower than K% of the rated cell voltage, the charging current is limited to M% of the established charging current; when the power battery cell voltage is higher than or equal to K% of the rated cell voltage, charging is stopped; and / or,

[0011] If the power battery temperature is higher than the first set temperature, the charging current is limited to N% of the established charging current. When the power battery temperature is higher than the second set temperature, charging is stopped.

[0012] The first set value is greater than the second set value; the first set temperature is less than the second set temperature.

[0013] The present invention classifies the total voltage, single cell voltage and charging temperature of the power battery, and performs hierarchical management on the charging and discharging process of the power battery, which is beneficial to the protection of the battery and improves the energy utilization rate of the locomotive.

[0014] The first set value is twice the second set value.

[0015] The difference between the first set temperature and the second set temperature is 10°C.

[0016] In the present invention, M=50, N=10, and K=15 are set.

[0017] Compared with the existing technology, the present invention has the following beneficial effects: the present invention can realize charging of vehicle-mounted power lithium batteries using multiple power supply modes (AC380V\DC1500V\AC25kV in the depot). The AC380V charging mode in the depot can manually set the charging current, and the charging power can be adjusted according to the actual capacity in the depot, effectively adjusting the charging time in the depot. In the contact network mode, the power difference can be calculated in real time to distribute power to the power battery charger, thereby optimizing the charging strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of a power lithium battery charging circuit according to an embodiment of the present invention;

[0019] FIG2 is a charging flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0021] In this document, the terms "first", "second" and other similar words are not intended to imply any order, quantity and importance, but are merely used to distinguish different elements. In this document, the terms "one", "an" and other similar words are not intended to indicate that there is only one of the things described, but rather that the relevant description is only for one of the things described, and the things described may have one or more. In this document, the terms "comprise", "include" and other similar words are intended to indicate logical relationships, and cannot be regarded as indicating relationships in spatial structure. For example, "A includes B" is intended to indicate that B logically belongs to A, and does not mean that B is spatially located inside A. In addition, the meanings of the terms "comprise", "include" and other similar words should be regarded as open, not closed. For example, "A includes B" is intended to indicate that B belongs to A, but B does not necessarily constitute the whole of A, and A may also include other elements such as C, D, and E.

[0022] The charging function of the power lithium battery of the hybrid battery locomotive in the embodiment of the present invention is integrated into the traction inverter and can be charged in three different ways. One way is through the overhead line, the second way is through the AC380V power supply in the depot, and the third way is through the DC1500V power supply in the depot. The main circuit diagram is shown in Figure 1. In Figure 1, the pantograph is connected to the overhead line. The pantograph is connected to one end of the traction transformer's primary winding via a vacuum circuit breaker. The other end of the traction transformer's primary (primary) winding is connected to the shaft grounding device. The first winding on the traction transformer's secondary side is connected to the first rectifier module, and the second winding is connected to the second rectifier module. Both rectifier modules are connected to the positive terminal of the intermediate DC link. The first and second charging modules are connected to the first and second power lithium batteries, respectively, and then connected in parallel with the intermediate DC link. The intermediate DC link is also connected in parallel to the 1500V DC power supply (the internal DC power supply) via an internal DC power connector. The positive terminal of the intermediate DC link is connected to the first and second auxiliary inverters, which are connected to the first and second auxiliary transformers AT1 and AT2, respectively. The first and second auxiliary transformers AT1 and AT2 are connected to the 380V AC power supply (the internal AC power supply) via an internal AC power connector. The first and second charging modules have identical structures, each consisting of two parallel-connected bridge arms, each with two series-connected IGBTs. The traction converter's TCU drives the IGBTs through a driver module, controlling the duty cycle of the bridge arm and thus achieving charging control. The in-depot DC power connector and in-depot AC power connector can be plugs and sockets.

[0023] The above charging functions are mainly implemented in the in-depot 380V charging mode, in-depot fast charging mode, and overhead line module. The control logic is as follows:

[0024] AC380V mode in the storage:

[0025] When the locomotive is stationary and the 380V charging mode is activated in the locomotive depot, the locomotive network control system (CCU) sends the mode command to the traction converter unit (TCU) through the MVB. At this time, the CCU controls the fast charging mode contactors (K03 and K04) and vacuum circuit breakers in the depot and prohibits them from closing. When the AC380V charging mode conditions in the depot are met (① the phase sequence of the AC380V power supply in the depot is normal, ② the mode selector switch is in the depot charging position, ③ the vacuum circuit breaker is in the disconnected state, and ④ the driver controller is in the zero position), The CCU closes the internal AC380V charging contactor (K01 or K02). After pre-charging is complete, the CCU sends an internal AC380V charging command to the TCU, which initiates the internal charging function. The internal AC380V power source charges the two power battery packs (the first and second power lithium battery packs) through two auxiliary transformers, two auxiliary inverters, an intermediate DC link (DC-Link), bidirectional charging modules (the first and second charging modules), and a reactor (L). In this mode, the driver and passengers can set the internal charging current on the microcomputer display. The maximum charging current limit for the power battery is 0.2C.

[0026] In-store fast charging mode

[0027] The locomotive is stationary. When the fast charging mode in the locomotive depot is activated, the CCU sends the mode command, power supply type, and charging connector closure status to the TCU through the MVB. The AC380V depot mode contactors (K01 and K02) and vacuum circuit breakers are not allowed to close. When the conditions for the fast charging mode in the depot are met (① the DC1500V power supply voltage range in the depot is normal, ② the mode selector switch is in the depot charging position, ③ the vacuum circuit breaker is in the disconnected state, and ④ the driver controller is in the zero position), the CCU controls the fast charging contactors in the depot (K03 or K04). After the pre-charging is completed, the CCU sends an in-depot fast charging command to the TCU, and the TCU starts the in-depot fast charging function. At this time, the DC1500V power supply in the depot charges the two power battery groups (the first power lithium battery and the second power lithium battery) respectively through the traction converter pre-charging circuit (including KM2A / KM2B and the intermediate DC link), the intermediate DC link (DC-Link), the two bidirectional charging modules (the first charging module and the second charging module) and the reactor (L). In this mode, the power battery charging current is set to 0.5C.

[0028] Catenary charging mode

[0029] When the locomotive overhead contact network working mode is activated, if the locomotive is in a stationary state, the CCU sends the overhead contact network working mode to the TCU through the MVB. The AC380V in-depot mode contactors (K01 and K02) and the in-depot fast charging contactors (K03 and K04) are not allowed to close. At this time, the AC25kV high-voltage electricity passes through the pantograph, vacuum circuit breaker, traction transformer, pre-charging circuit (including KM2A / KM2B and intermediate DC link), intermediate DC link (DC-Link), two bidirectional charging modules ((first charging module and second charging module)) and reactor (L) to charge the two power battery groups (first power lithium battery and second power lithium battery) respectively. In this mode, the power battery charging current is set to 1C.

[0030] If the locomotive is in traction state, the TCU calculates the real-time power based on the locomotive's real-time speed V and traction force F, and sends the real-time power to the CCU through the MVB. The CCU makes a judgment based on the real-time power of the locomotive and the power of the entire vehicle. When the real-time power is the full power of the entire vehicle, the TCU does not charge the power battery; when the real-time power is less than the full power of the entire vehicle, the CCU sends the difference between the real-time power and the power of the entire vehicle to the TCU, and the TCU charges in real time according to half of the power difference.

[0031] In any of the above operating modes, when the voltage difference between the total power battery voltage and the output voltage of the charging module is less than 100V, the charging module will limit the charging current to 50% of the established charging current. When the voltage difference between the total power battery voltage and the output voltage of the charging module is less than 50V, the charging module will stop charging. When the power battery cell voltage is higher than 10% and lower than 15% of the rated cell voltage, the charging current is limited to 50% of the established charging current. When the power battery cell voltage is higher than or equal to 15% of the rated cell voltage, the charging module will stop charging. When the power battery temperature is greater than 50°C, the charging module will limit the charging current to 50% of the established charging current. When the power battery temperature is greater than 60°C, the charging module will stop charging.

[0032] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0033] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A hybrid battery locomotive power lithium battery charging control circuit, characterized in that: It includes a traction transformer, the primary side of which receives a pantograph, the secondary side of which is connected to a first rectifier module and a second rectifier module, the first rectifier module and the second rectifier module are connected to an intermediate DC link, the intermediate DC link is connected to a first charging module, a second charging module and an in-depot DC power connector, the intermediate DC link is connected to two auxiliary inverters, each of which is connected to an auxiliary transformer, and both of the two auxiliary transformers are connected to an in-depot AC power connector; the first charging module and the second charging module are respectively connected to a first power battery pack and a second power battery pack.

2. The hybrid battery locomotive power lithium battery charging control circuit according to claim 1, characterized in that: The intermediate DC link is connected to the DC power connector in the warehouse through a fast charging mode contactor.

3. The hybrid battery locomotive power lithium battery charging control circuit according to claim 1, characterized in that: The two auxiliary transformers are connected to the AC power connector in the warehouse through charging contactors.

4. A hybrid battery locomotive power lithium battery charging control method, characterized in that: The method includes: Determine whether the voltage difference between the total voltage of the power storage battery and the charging voltage is lower than a first set value. If so, limit the charging current to M% of the predetermined charging current. When the voltage difference between the total voltage of the power storage battery and the charging voltage is lower than a second set value, stop charging; and / or, If the power battery cell voltage is higher than N% of the rated cell voltage and lower than K% of the rated cell voltage, the charging current is limited to M% of the predetermined charging current. When the power battery cell voltage is higher than or equal to K% of the rated cell voltage, charging is stopped; and / or, If the power battery temperature is higher than the first set temperature, the charging current is limited to N% of the predetermined charging current. When the power battery temperature is higher than the second set temperature, charging is stopped. Among them, the first set value is greater than the second set value; the first set temperature is lower than the second set temperature.

5. The hybrid battery locomotive power lithium battery charging control method according to claim 4, characterized in that: The first setting value is twice the second setting value.

6. The hybrid battery locomotive power lithium battery charging control method according to claim 4, characterized in that: The difference between the first set temperature and the second set temperature is 10°C.

7. The hybrid battery locomotive power lithium battery charging control method according to claim 4, characterized in that: M=50, N=10, K=15. 8.[Corrected 07.01.2025 in accordance with Rule 26][Deleted]

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