Multi-source hybrid shunting locomotive power system and management strategy

Abstract

The invention provides a multi-source hybrid shunting locomotive power system and a management strategy, and the method comprises an energy storage system which is electrically connected with a shunting locomotive traction converter, the energy storage system supplies power to a traction motor and an auxiliary system which are connected with the traction converter through the traction converter, and the traction motor controls a wheel pair; the energy storage system comprises a storage battery pack and a DC / DC converter; the range extender is used for charging the energy storage system, and when the residual electric quantity of the energy storage system is lower than a preset value, the range extender is started to charge the energy storage system. The energy storage system is charged through the range extender, so that the shunting locomotive can adapt to various different environments and working conditions, the multi-source power shunting locomotive power system convenient to transform and manufacture is high in energy efficiency ratio, compared with a pure oil power system, generation of a large amount of waste gas caused by idling operation and frequent alternating load of a diesel engine is reduced, and the energy efficiency of the diesel engine is improved. And the system is low in maintenance cost.

Description

Technical Field

[0001] The present invention relates to the technical field of shunting locomotive power systems, and in particular to a multi-source hybrid shunting locomotive power system and management strategy. Background Art

[0002] Due to the demand for a new generation of electric, hybrid, new energy and multi-source locomotives, the existing diesel shunting locomotives have major defects. Because of the diesel engine power generation, preheating, insulation, waiting and other working modes, the diesel engine needs to run at idle speed, which makes the diesel engine idle for a long time and inefficient; and the diesel engine is frequently in alternating load, the fuel consumption is high and the combustion is not complete. Therefore, the new energy transformation of diesel shunting locomotives and the design and manufacture of new energy shunting locomotives are currently problems that need to be solved or optimized.

[0003] The design of the shunting locomotive power system is an important issue that needs to be solved in the research of multi-source power shunting locomotives. The power system is the core system of the shunting locomotive, which determines the ability of the shunting locomotive to perform various tasks. The shunting locomotive with an excellent power system has high energy efficiency, low operating noise and low exhaust emissions. The power systems of shunting locomotives mainly include internal combustion engine power systems, pure electric power systems and hybrid power systems. The traditional internal combustion engine power system is in urgent need of updating and iteration, while the pure electric power system is relatively expensive and has poor adaptability to low temperature environments. Therefore, continuing to provide a hybrid power system is the solution to the above problems of the shunting locomotive power system. Summary of the invention

[0004] In order to overcome the problems existing in the related technologies, the present disclosure provides a multi-source hybrid shunting locomotive power system and management strategy to solve the technical problems in the above technologies.

[0005] One or more embodiments of the present specification provide a multi-source hybrid shunting locomotive power system, including:

[0006] An energy storage system electrically connected to the traction converter of the shunting locomotive, the energy storage system supplies power to the traction motor and auxiliary system connected to the traction converter through the traction converter, so as to realize the traction motor controlling the wheelset; the energy storage system includes a battery pack and a DC / DC converter; and

[0007] It also includes a range extender for charging the energy storage system. When the remaining power of the energy storage system is lower than a preset value, the range extender is started to charge the energy storage system.

[0008] Furthermore, the range extender includes a diesel generator and a three-phase PWM rectifier module, the three-phase PWM rectifier module outputs DC power and is connected to a battery pack, and the output power of the range extender is greater than 100% of the power requirement of the traction motor of the shunting locomotive under operating conditions.

[0009] Furthermore, the energy storage system is also provided with a supercapacitor, which is connected to the traction converter via a DC / DC converter. When the shunting locomotive is under large traction conditions, the supercapacitor and the battery pack simultaneously supply power to the traction converter, and the supercapacitor is used as a DC side bus capacitor of the traction converter to adjust the DC side voltage of the traction converter.

[0010] Furthermore, the traction inverter is a four-quadrant inverter, and the DC / DC converter is a bidirectional DC / DC converter, so that when the shunting locomotive is in a braking condition, the traction inverter enters a rectification mode, and the regenerative braking energy is reduced in voltage and rectified, and then recovered to a supercapacitor or a battery pack after being reduced in voltage by a bidirectional DC / DC converter.

[0011] Furthermore, during the braking condition, the traction inverter steps down and rectifies the regenerative braking energy, and then steps down the energy through the bidirectional DC / DC converter before transferring it to the supercapacitor for storage. When it is detected that the voltage of the supercapacitor is greater than a preset voltage value, the bidirectional DC / DC converter relies on current changes to switch the energy to the battery pack for charging while keeping the voltage polarity unchanged.

[0012] One or more embodiments of this specification provide a control strategy for a multi-source hybrid shunting locomotive power system, based on any one of the multi-source hybrid shunting locomotive power systems described above, including control strategies corresponding to traction conditions and coasting conditions:

[0013] Under traction conditions, the control unit controls the battery pack to output energy through the DC / DC converter, and drives the traction motor and supplies power to the loads in the auxiliary system through the traction converter. When it is detected that the SOC of the battery pack is lower than the preset value, the control unit controls the range extender to charge the battery pack, and if the shunting locomotive is in operation, the range extender will be switched to provide energy for the power system.

[0014] Under coasting conditions, the energy storage system stops outputting electrical energy, and the shunting locomotive relies on its own inertia to move forward while slowly decelerating. The battery pack outputs energy through the DC / DC converter and only supplies power to the auxiliary system through the traction inverter.

[0015] Furthermore, it also includes the corresponding control strategy under braking conditions, specifically:

[0016] When the shunting locomotive is going downhill or in a braking condition, the system enters the regenerative braking condition, and the traction motor absorbs the regenerative braking energy generated by the wheelset. The regenerative braking energy is stepped down and rectified by the traction inverter to obtain a stable DC voltage, which is then stepped down by a bidirectional DC / DC converter and input into the supercapacitor group of the supercapacitor energy storage device for storage. When it is detected that the voltage of the supercapacitor is greater than the preset voltage value, the bidirectional DC / DC converter relies on the change in current to switch and transmit energy to the battery pack for charging while the voltage polarity remains unchanged.

[0017] Furthermore, it also includes the corresponding control strategy under high-power traction conditions, specifically:

[0018] When the shunting locomotive is heavily loaded or climbing a slope and is in high-power traction, the bidirectional DC / DC converter is in boost mode, and the control unit controls the battery pack and the supercapacitor to jointly output energy through the bidirectional DC / DC converter. The energy jointly output by the battery pack and the supercapacitor is supplied to the traction motor and the load in the auxiliary system through the traction inverter.

[0019] Furthermore, it also includes a control strategy for the starting condition, that is, when the shunting locomotive is in the starting mode, the battery pack charges the supercapacitor through the DC / DC converter.

[0020] Furthermore, it also includes a control strategy for charging conditions. When the SOC of the battery pack is lower than a preset value, the on-site power generation mode can be manually started and the battery pack can be charged by the range extender.

[0021] The present disclosure provides a multi-source hybrid shunting locomotive power system and management strategy, which have the advantages that, compared with a pure electric system, the multi-source hybrid shunting locomotive power system with a range extender and an energy storage system can charge the energy storage system through the range extender so that the shunting locomotive can adapt to a variety of different environments and working conditions. The multi-source power shunting locomotive power system is easy to transform and manufacture, has a high energy efficiency ratio, and compared with a pure oil power system, reduces the need for the diesel engine to run at idle speed and frequently be in alternating loads, resulting in a large amount of exhaust gas generation, and the system has a low maintenance cost. The system of this embodiment can provide guiding suggestions for the new energy transformation of internal combustion shunting locomotives and the design of new energy shunting locomotives, making the new shunting locomotive power system more reliable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of a multi-source hybrid shunting locomotive power system structure provided for one or more embodiments of this specification;

[0024] Figure 2 A schematic diagram of energy flow of a shunting locomotive in extended range mode provided for one or more embodiments of this specification;

[0025] Figure 3 A schematic diagram of energy flow of a shunting locomotive under high-power traction conditions provided by one or more embodiments of this specification;

[0026] Figure 4 A schematic diagram of energy flow of a shunting locomotive under a startup condition provided by one or more embodiments of this specification;

[0027] Figure 5 A schematic diagram of energy flow of a shunting locomotive under braking conditions provided for one or more embodiments of this specification; and

[0028] Figure 6 A schematic diagram of energy flow of a shunting locomotive under idling conditions provided for one or more embodiments of this specification. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] The present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.

[0031] System Example

[0032] According to an embodiment of the present invention, a multi-source hybrid shunting locomotive power system is provided, such as Figure 1 As shown, it is a schematic diagram of the structure of a multi-source hybrid shunting locomotive power system provided in this embodiment. The multi-source hybrid shunting locomotive power system according to an embodiment of the present invention includes:

[0033] The energy storage system is electrically connected to the traction inverter of the shunting locomotive. The energy storage system supplies power to the traction motor and auxiliary system connected to the traction inverter through the traction inverter, thereby realizing the traction motor controlling the wheelset.

[0034] Also included is a range extender for charging the energy storage system, reference Figure 2 As shown, when the remaining power (SOC, State of Charge) of the energy storage system is lower than the preset value, the range extender is started to charge the energy storage system, and if the shunting locomotive is in operation, the range extender will be switched to provide energy for the power system;

[0035] In this embodiment, the range extender charges the energy storage system. When the remaining power of the energy storage system is lower than a preset value, the range extender generates electricity to provide energy for the power system and charges the energy storage system at the same time. In most cases, the battery pack cannot be charged and discharged at the same time, and can be regarded as an intermediate link.

[0036] In this embodiment, the energy storage system includes a battery pack and a bidirectional DC / DC converter.

[0037] In this embodiment, the range extender includes a diesel generator and a three-phase PWM rectifier module. The three-phase PWM rectifier module outputs direct current power and is connected to a battery pack.

[0038] In this embodiment, the output power of the range extender is greater than 100% of the power demand of the conventional traction motor of the shunting locomotive under operating conditions.

[0039] In this embodiment, the shunting locomotive power system is an extended-range hybrid power system or a series hybrid power system, such as a series hybrid power system in which a diesel range extender, an energy storage system and a traction motor are in series.

[0040] The multi-source hybrid shunting locomotive power system provided in the present embodiment and provided with a range extender and an energy storage system, compared with a pure electric system, enables the shunting locomotive to adapt to a variety of different environments and working conditions by charging the energy storage system through the range extender. The multi-source power shunting locomotive power system is easy to transform and manufacture, has a high energy efficiency ratio, and compared with a pure oil power system, reduces the large amount of exhaust gas generated by the diesel engine due to the need to idle and frequently being in alternating loads, and the maintenance cost of the system is low. The system in the present embodiment can provide guiding suggestions for the new energy transformation of internal combustion shunting locomotives and the design of new energy shunting locomotives, making the new shunting locomotive power system more reliable and reliable.

[0041] In this embodiment, considering that the shunting locomotive is under starting or heavy load conditions, and the battery pack has a large energy density, large current discharge has an adverse effect on the life and efficiency of the battery pack. Therefore, the energy storage system is further provided with a supercapacitor, which is connected to the traction converter through a bidirectional DC / DC converter, such as Figure 3As shown, when the shunting locomotive is in a large traction condition such as climbing or heavy load, the supercapacitor and the battery pack simultaneously supply power to the traction inverter, and the supercapacitor serves as the DC side bus capacitor of the traction inverter to adjust the DC side voltage of the traction inverter; when the supercapacitor and the battery pack simultaneously supply power to the traction inverter, the battery pack is mainly used for power supply, and the supercapacitor is responsible for filling the remaining power demand that the battery pack cannot supply; when the shunting locomotive enters the regenerative braking condition, the traction motor absorbs the regenerative braking energy generated by the wheels of the shunting locomotive, works in the generator mode, and obtains a stable DC voltage after voltage reduction and rectification through the traction inverter to charge the supercapacitor and supply power to the auxiliary system; when the shunting locomotive is started, as shown in FIG. Figure 4 As shown, the battery pack charges the supercapacitor through the DC / DC converter to prepare for the start-up of the shunting locomotive.

[0042] Preferably, in this embodiment, when the remaining power of the energy storage system is lower than a preset value and the shunting locomotive is in a low-power traction condition, the supercapacitor is switched to power the traction inverter, and the range extender only charges the energy storage system; when the shunting locomotive is in a high-power traction condition and the SOC of the battery pack is also lower than a certain value, the range extender is started to power the battery pack, and at the same time, the range extender and the supercapacitor power the traction inverter at the same time.

[0043] In this embodiment, the traction inverter is a four-quadrant inverter. When the shunting locomotive is in a braking condition, the traction inverter can operate in a rectification mode to recover regenerative braking energy to the supercapacitor or the battery pack.

[0044] In this embodiment, the bidirectional DC / DC converter includes two working modes according to the working condition of the shunting locomotive. Specifically, when the shunting locomotive enters the regenerative braking condition, for example, the shunting locomotive is in a downhill or braking state, the bidirectional DC / DC converter is in a step-down mode; when the shunting locomotive performs high-power traction, such as starting or going uphill, the bidirectional DC / DC converter is in a step-up mode.

[0045] In a preferred embodiment, Figure 5As shown, according to the working mode of the above-mentioned bidirectional DC / DC converter, under regenerative braking conditions, the regenerative braking energy is reduced and rectified by the traction converter to obtain a stable DC voltage, and then the DC voltage is reduced by the bidirectional DC / DC converter, and finally the energy after the voltage reduction is input into the supercapacitor group of the supercapacitor energy storage device for storage; when the voltage of the supercapacitor is greater than the preset voltage value, the bidirectional DC / DC converter relies on the change of current, and switches to charge the battery group under the condition that the voltage polarity remains unchanged. In this way, when the shunting locomotive is in the traction stage, the energy storage system provides power to the shunting locomotive, and when the shunting locomotive is in the braking stage, the braking energy is fed back to the energy storage system, avoiding a series of problems caused by the voltage fluctuation.

[0046] In this embodiment, when the shunting locomotive is stopped on site but the SOC of the battery pack is low, the driver can manually start the on-site power generation mode, and the range extender charges the battery pack;

[0047] It also includes a thermal management system, which is used to heat the battery pack through the waste heat of the range extender when the shunting locomotive is running under low temperature conditions, so that the battery pack is in a good working condition.

[0048] The multi-source hybrid shunting locomotive power system provided in this embodiment, during the operation of the shunting locomotive, under normal conditions, the power output of the battery pack is adjusted by the DC / DC converter, and the traction inverter and other devices are powered. When the SOC of the battery pack is lower than the preset value, the control system starts the range extender to charge the energy storage system, and the diesel internal combustion engine maintains a constant output power, charging the battery pack until the SOC of the battery pack reaches the preset value, and is always in a high-efficiency operation state, which can reduce the energy waste caused by incomplete diesel combustion. When the shunting locomotive is in the starting or overload condition, the control system controls the battery pack and the supercapacitor to power the traction inverter at the same time; when the power system enters the regenerative braking condition, the traction motor absorbs the regenerative braking energy generated by the shunting locomotive wheel set, works in the generator mode, and obtains a stable DC voltage after voltage reduction and rectification through the traction inverter, charges the supercapacitor and powers the auxiliary system.

[0049] Control Strategy Example

[0050] According to an embodiment of the present invention, a control strategy for a multi-source hybrid shunting locomotive power system is provided. Based on the multi-source hybrid shunting locomotive power system, different control strategies are executed to supply power to the shunting locomotive according to different working conditions, including the control strategies corresponding to the traction working condition and the coasting working condition are as follows:

[0051] When the shunting locomotive is traction, the bidirectional DC / DC converter is in boost mode. The control unit controls the energy storage system to output energy through the DC / DC converter, and drives the traction motor and supplies power to the loads in the auxiliary system through the traction converter. When the SOC of the energy storage system is detected to be lower than the preset value, Figure 2 As shown, the control unit controls the range extender to charge the energy storage system, and if the shunting locomotive is in operation, the range extender is switched to provide energy for the power system.

[0052] The corresponding control strategy under the coasting condition is as follows:

[0053] When the shunting locomotive reaches the maximum speed or the maximum speed limit, the power system enters the coasting condition, such as Figure 6 As shown, the energy storage system stops outputting electric energy, the shunting locomotive moves forward by its own inertia while slowly decelerating, the battery pack outputs energy through the DC / DC converter, and only supplies power to the auxiliary system through the traction inverter.

[0054] In this embodiment, the energy storage system is charged by the range extender, so that the shunting locomotive can adapt to a variety of different environments, and the multi-source power shunting locomotive power system is easy to modify and manufacture. It has a high energy efficiency ratio, and compared with the pure oil power system, it reduces the need for the diesel engine to run at idle speed and frequently be in alternating loads, resulting in a large amount of exhaust gas generation. The system has low maintenance costs and is always in a high-efficiency operating state.

[0055] In this embodiment, corresponding control strategies under charging conditions, high-power traction conditions and braking conditions are also included.

[0056] The specific control strategy under the starting condition is: when the shunting locomotive is started, the battery pack charges the supercapacitor through the DC / DC converter to prepare for the start-up operation of the shunting locomotive.

[0057] The specific control strategy for high-power traction conditions is: when the shunting locomotive is heavily loaded or climbing and is in high-power traction, Figure 3 As shown, at this time, the bidirectional DC / DC converter is in the boost mode, and the control unit controls the battery pack and the supercapacitor to jointly output energy through the DC / DC converter. The energy jointly output by the battery pack and the supercapacitor is supplied to the traction motor and the load in the auxiliary system respectively through the traction inverter, wherein the energy output by the supercapacitor is used to make up for part of the power that the battery pack cannot bear.

[0058] The corresponding control strategy under braking condition is: when the shunting locomotive is going downhill or in braking condition, the system enters regenerative braking condition, such as Figure 5As shown, the traction motor absorbs the regenerative braking energy generated by the wheelset, and the regenerative braking energy is reduced and rectified by the traction converter to obtain a stable DC voltage, and then the DC voltage is reduced by the bidirectional DC / DC converter, and finally the energy after the voltage reduction is input into the supercapacitor group of the supercapacitor energy storage device for storage. When the voltage of the supercapacitor is greater than the preset voltage value, the bidirectional DC / DC converter relies on the change of current, and switches to charge the battery group when the voltage polarity remains unchanged. In this way, when the shunting locomotive is in the traction stage, the energy storage system provides power to the shunting locomotive, and when the shunting locomotive is in the braking stage, the braking energy is fed back to the energy storage system, avoiding a series of problems caused by voltage fluctuations. The control strategy is simple and the stability is strong.

[0059] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A multi-source hybrid shunting locomotive power system, characterized in that include: An energy storage system electrically connected to the traction converter of the shunting locomotive, the energy storage system supplies power to the traction motor and auxiliary system connected to the traction converter through the traction converter, so as to realize the traction motor controlling the wheelset; the energy storage system includes a battery pack and a DC / DC converter; and It also includes a range extender for charging the energy storage system. When the remaining power of the energy storage system is lower than a preset value, the range extender is started to charge the energy storage system.

2. A multi-source hybrid shunting locomotive power system as claimed in claim 1, characterized in that: The range extender includes a diesel generator and a three-phase PWM rectifier module. The three-phase PWM rectifier module outputs DC power and is connected to a battery pack. The output power of the range extender is greater than 100% of the power demand of the traction motor of the shunting locomotive under the operating condition.

3. A multi-source hybrid shunting locomotive power system as claimed in claim 1, characterized in that: The energy storage system is also provided with a supercapacitor, which is connected to the traction inverter through a DC / DC converter. When the shunting locomotive is under large traction conditions, the supercapacitor and the battery pack simultaneously supply power to the traction inverter, and the supercapacitor serves as a DC side bus capacitor of the traction inverter to adjust the DC side voltage of the traction inverter.

4. A multi-source hybrid shunting locomotive power system as claimed in claim 1, characterized in that: The traction inverter is a four-quadrant inverter, and the DC / DC converter is a bidirectional DC / DC converter. When the shunting locomotive is in a braking condition, the traction inverter enters a rectification mode, and after reducing the voltage and rectifying the regenerative braking energy, it is recovered to a supercapacitor or a battery pack after being reduced by the bidirectional DC / DC converter.

5. A multi-source hybrid shunting locomotive power system as claimed in claim 4, characterized in that: During the braking condition, the traction inverter steps down and rectifies the regenerative braking energy, and then steps down the energy through the bidirectional DC / DC converter before transferring it to the supercapacitor for storage. When it is detected that the voltage of the supercapacitor is greater than a preset voltage value, the bidirectional DC / DC converter relies on current changes to switch and transfer energy to the battery pack for charging while keeping the voltage polarity unchanged.

6. A control strategy for a multi-source hybrid shunting locomotive power system, characterized in that: The multi-source hybrid shunting locomotive power system according to any one of claims 1 to 5 includes control strategies corresponding to traction conditions and coasting conditions: Under traction conditions, the control unit controls the battery pack to output energy through the DC / DC converter, and drives the traction motor and supplies power to the loads in the auxiliary system through the traction converter. When it is detected that the SOC of the battery pack is lower than the preset value, the control unit controls the range extender to charge the battery pack, and if the shunting locomotive is in operation, the range extender will be switched to provide energy for the power system. Under coasting conditions, the energy storage system stops outputting electrical energy, and the shunting locomotive relies on its own inertia to move forward while slowly decelerating. The battery pack outputs energy through the DC / DC converter and only supplies power to the auxiliary system through the traction inverter.

7. The control strategy of the multi-source hybrid shunting locomotive power system according to claim 6, characterized in that: It also includes the corresponding control strategy under braking conditions, specifically: When the shunting locomotive is going downhill or in a braking condition, the system enters the regenerative braking condition, and the traction motor absorbs the regenerative braking energy generated by the wheelset. The regenerative braking energy is stepped down and rectified by the traction inverter to obtain a stable DC voltage, which is then stepped down by a bidirectional DC / DC converter and input into the supercapacitor group of the supercapacitor energy storage device for storage. When it is detected that the voltage of the supercapacitor is greater than the preset voltage value, the bidirectional DC / DC converter relies on the change in current to switch and transmit energy to the battery pack for charging while the voltage polarity remains unchanged.

8. The control strategy of the multi-source hybrid shunting locomotive power system according to claim 6, characterized in that: It also includes the corresponding control strategy under high-power traction conditions, specifically: When the shunting locomotive is heavily loaded or climbing a slope and is in high-power traction, the bidirectional DC / DC converter is in boost mode, and the control unit controls the battery pack and the supercapacitor to jointly output energy through the bidirectional DC / DC converter. The energy jointly output by the battery pack and the supercapacitor is supplied to the traction motor and the load in the auxiliary system through the traction inverter.

9. The control strategy of the multi-source hybrid shunting locomotive power system according to claim 7, characterized in that: It also includes a control strategy for the starting condition, that is, when the shunting locomotive is in the starting mode, the battery pack charges the supercapacitor through the DC / DC converter.

10. The control strategy of the multi-source hybrid shunting locomotive power system according to claim 6, characterized in that: It also includes a control strategy for charging conditions. When the SOC of the battery pack is lower than the preset value, the on-site power generation mode can be manually started and the range extender can charge the battery pack.

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