Main circuit of hydrogen energy hybrid power vehicle and rail vehicle

Abstract

The invention discloses a main circuit of a hydrogen energy hybrid power machine, which is characterized in that a chopping module is additionally arranged in a traction converter to form a boost chopping discharge circuit and a buck chopping charge circuit on a power battery side together with an electric reactor, so that the voltage output to an intermediate direct current loop by a power battery is stabilized at DC1800V; meanwhile, the circuit safety of the power battery side is improved through the stable and controllable charging circuit; the hydrogen fuel power supply module directly obtains a starting power supply from the intermediate direct current loop through the bidirectional isolated voltage boosting / reducing module, and after the hydrogen fuel power supply module is started, the stability and timeliness of forward voltage boosting control of the voltage boosting / reducing module can be improved through the stable intermediate direct current loop voltage. According to the invention, consistency control of the intermediate voltage in different power supply modes is realized, and system faults caused by inconsistency of the intermediate voltage in the same main transmission system in different power supply modes are reduced. The invention further provides a railway vehicle.

Description

Technical Field

[0001] The invention relates to a main circuit of a hydrogen energy hybrid power locomotive and a rail vehicle, belonging to the technical field of traction power supply systems in the rail transportation industry. Background Art

[0002] Hydrogen hybrid locomotives are currently an important development direction in the field of rail transit. Hydrogen fuel cells, with their advantages of being green, efficient, high calorific value, zero carbon emissions, and low noise, have been widely used in the fields of automobiles, rail transit, and ships, effectively alleviating the greenhouse effect and environmental pollution, reducing environmental protection investment, and improving the working environment of operators.

[0003] Existing hydrogen-powered locomotives must be equipped with energy storage battery systems. The start and stop of hydrogen fuel cells mostly rely on the voltage output and energy recovery of the power battery. A separate hydrogen fuel system cannot be used directly. At present, the hydrogen fuel system of conventional hydrogen-powered hybrid locomotives is directly connected to the output end of the power battery, such as Figure 1 As shown. This connection method often causes the voltage output of the hydrogen fuel system to fail to follow the DC bus voltage well, resulting in frequent overvoltage and overcurrent faults in the system, and seriously leading to emergency shutdown of the hydrogen fuel system stack, increasing the stack failure rate, and reducing the service life of the stack. At the same time, the use of hybrid power supply locomotives of hydrogen fuel and power batteries is limited, that is, the fixed hydrogen fuel storage capacity and power battery capacity limit the locomotive's cruising range and operating routes. Therefore, it is urgent to provide a new locomotive main circuit design scheme to effectively solve the above problems and expand the practicality of the locomotive. Summary of the invention

[0004] The present invention aims to provide a main circuit of a hydrogen energy hybrid locomotive and a rail vehicle, so as to realize the consistency control of the intermediate voltage under different power supply modes and effectively improve the control timeliness of the high voltage side of the hydrogen fuel hybrid system.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a main circuit of a hydrogen energy hybrid locomotive, the main circuit comprising: a power battery module, a hydrogen fuel power supply module and a traction converter;

[0006] The traction converter includes a first short-circuit pre-charging unit, a chopper module and an intermediate DC circuit; the output end of the power battery module is connected to the input end of the first short-circuit pre-charging unit through a reactor, and the output end of the first short-circuit pre-charging unit is connected to the intermediate DC circuit through the chopper module;

[0007] The output end of the hydrogen fuel power supply module is connected to the intermediate DC circuit through a voltage step-up / step-down module.

[0008] The voltage stabilization control of the conventional hydrogen fuel system is voltage following control, that is, it is controlled according to the voltage of the power battery at the output end. The voltage of the power battery will also mutate with the sudden change of the load, which will cause the power battery under high power to have an overcurrent fault due to low voltage, and will cause the voltage control of the hydrogen fuel system output to be more complicated and not easy to follow. The main circuit of the hydrogen energy hybrid power supply locomotive provided by the present invention does not directly connect the power battery and the hydrogen fuel output end in parallel, but enters the intermediate DC circuit through a boost circuit respectively, and relies on the voltage stabilization control of the intermediate DC circuit to stabilize the voltage, for example, DC1800V. Regardless of the output of the hydrogen fuel system or the output of the power battery system, the voltage entering the intermediate DC circuit is a stable value, thereby ensuring the stable operation of the traction system.

[0009] According to the embodiments of the present invention, the present invention can be further optimized. The following is the technical solution formed after optimization:

[0010] In one of the preferred embodiments, the main circuit also includes a contact network power supply module; the traction inverter also includes a second short-circuit pre-charging unit and a four-quadrant inverter; the output end of the contact network power supply module is connected to the input end of the second short-circuit pre-charging unit, and the output end of the second short-circuit pre-charging unit is connected to the intermediate DC circuit through the four-quadrant inverter.

[0011] According to the locomotive main circuit of the existing overhead power supply system, the present invention also proposes a three-source hydrogen production energy hybrid locomotive main circuit that can work under the overhead power supply and is equipped with hydrogen fuel and power batteries. The locomotive main circuit can realize smooth switching between overhead power supply, hydrogen fuel hybrid power supply and power battery power supply modes, which can effectively solve the disadvantages that the locomotive operating route and cruising range are limited by the power supply mode, and expand the practicality of the locomotive.

[0012] In one preferred embodiment, the first short-circuit pre-charging unit includes a first output contactor and a first short-circuit contactor, the first output contactor and the first short-circuit contactor are connected in parallel, and one end of the first short-circuit contactor is connected to a first resistor; and / or the second short-circuit pre-charging unit includes a second output contactor and a second short-circuit contactor, the second output contactor and the second short-circuit contactor are connected in parallel, and one end of the second short-circuit contactor is connected to a second resistor.

[0013] When the power battery module is in a discharging state, the reactor, the output contactor of the first short-circuit pre-charging unit and the chopper module form a step-up chopper discharge circuit; when the power battery module is in a charging state, the reactor, the short-circuit contactor of the first short-circuit pre-charging unit and the chopper module form a step-down chopper charging circuit.

[0014] In one preferred embodiment, the traction converter is also connected to a braking resistor, a traction motor and an auxiliary load respectively.

[0015] In the hydrogen fuel hybrid power supply or power battery power supply mode, when the locomotive is in regenerative braking, the regenerative braking energy fed back by the traction motor is used to pre-charge the power battery module. When the power battery module cannot be charged, the braking resistor is used to consume the remaining energy.

[0016] In one of the preferred embodiments, the braking resistor is connected to the intermediate DC circuit through a first DC / DC module; the traction motor is connected to the intermediate DC circuit through a first DC / AC module; and the auxiliary load is connected to the intermediate DC circuit through a second DC / AC module.

[0017] In one preferred embodiment, the voltage step-up / step-down module is a DC / DC converter.

[0018] Based on the same concept, the present invention also provides a power supply method for the main circuit of the above-mentioned hydrogen energy hybrid locomotive, including a power battery power supply mode, a hydrogen fuel hybrid power supply mode and a contact network power supply mode:

[0019] In the power battery power supply mode: that is, when the power battery module is in the discharge state, the output voltage of the power battery module is boosted to DC1800V through the boost chopper discharge circuit to supply power to the intermediate DC circuit;

[0020] In the hydrogen fuel hybrid power supply mode: before the hydrogen fuel power supply module is started, the power battery module first supplies power to the intermediate DC circuit through the boost chopper discharge circuit, and the intermediate DC circuit reversely steps down the voltage through the boost / step-down module to provide starting power to the hydrogen fuel power supply module; after the hydrogen fuel power supply module is started, the boost / step-down module forward boosts the voltage to control the output voltage to be stable at DC1800V;

[0021] In the overhead contact power supply mode: the overhead contact power supply module supplies power to the intermediate DC circuit, and the voltage is stabilized at DC1800V.

[0022] The stability of the output voltage on the DC / DC side of the hydrogen fuel power supply module is related to whether the voltage of the intermediate DC loop is stable, and its essence is the stability control of the intermediate DC loop voltage. The present invention realizes the consistency control of the intermediate voltage under different power supply modes, and reduces the system failure caused by the inconsistency of the intermediate voltage of the same main transmission system under different power supply modes. At the same time, the stable intermediate DC loop voltage can effectively improve the stability and timeliness of the DC / DC forward boost control of the hydrogen fuel power supply system.

[0023] In one preferred embodiment, the traction converter is also connected to a braking resistor, a traction motor and an auxiliary load respectively; and the power supply method further comprises:

[0024] In the power battery power supply mode: when the locomotive is in regenerative braking, the feedback energy generated by the traction motor is charged to the power battery module through the step-down chopper charging circuit, and when the power battery module cannot be charged, the remaining energy is consumed through the braking resistor;

[0025] In the hydrogen fuel hybrid power supply mode: when the locomotive is in regenerative braking, the braking resistor chopper circuit and the step-down chopper charging circuit are turned on to consume the residual energy output from the hydrogen fuel power supply module to the intermediate DC circuit;

[0026] In the overhead power supply mode: when the locomotive is in regenerative braking, the feedback energy generated by the traction motor is first used to charge the power battery module. When the power battery module cannot be charged, the remaining energy is returned to the overhead power supply module through the intermediate DC circuit.

[0027] And / or the intermediate DC circuit power supply voltage is DC1850V.

[0028] When the hydrogen fuel system is shut down or shut down in an emergency, and when the locomotive is regeneratively braked, the main circuit provided by the present invention can smoothly switch between the step-down chopper charging circuit and the brake resistor chopper circuit, and promptly and effectively handle the energy flow of the intermediate DC circuit, thereby avoiding overcharging of the power battery or overvoltage failure of the intermediate voltage.

[0029] Based on the same concept, the present invention also provides a rail vehicle, on which the above-mentioned hydrogen energy hybrid locomotive main circuit is provided.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: the main circuit of the hydrogen energy hybrid locomotive provided by the present invention, by adding a chopper module in the traction inverter, forms a boost chopper discharge circuit and a buck chopper charging circuit on the power battery side with the inductor, so that the voltage output from the power battery to the intermediate DC circuit is stabilized at DC1800V, and at the same time, the stable and controllable charging circuit improves the circuit safety on the power battery side; the hydrogen fuel power supply module directly obtains the starting power supply from the intermediate DC circuit through the boost / buck module. After the hydrogen fuel power supply module is started, the stable intermediate DC circuit voltage can improve the stability and timeliness of the forward boost control of the boost / buck module. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the main circuit topology of a conventional hydrogen fuel hybrid locomotive;

[0032] Figure 2is a schematic diagram of the main circuit topology of a hydrogen fuel hybrid locomotive according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of energy flow in a power battery power supply mode according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of energy flow in a hydrogen fuel hybrid power supply mode according to an embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of energy flow in a hydrogen fuel hybrid power supply mode according to another embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of energy flow in a contact network power supply mode according to another embodiment of the present invention;

[0037] Figure 7 It is a schematic diagram of energy flow in a regenerative braking condition according to another embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0039] Example 1

[0040] In order to solve the above-mentioned problems of control timeliness of the high-voltage output end of the hydrogen fuel system and the problem of limited power supply mode of hydrogen fuel hybrid locomotives, this embodiment 1 proposes a three-source hydrogen energy hybrid traction control circuit based on the existing 25kV high-voltage power supply locomotive main circuit. The locomotive main circuit structure includes: 25kV grid-side high-voltage circuit, traction transformer, traction converter, hydrogen fuel power supply system, power battery power supply system, reactor, braking resistor, traction motor, auxiliary load, etc. The locomotive main circuit can realize arbitrary switching between contact network power supply, hydrogen fuel hybrid power supply and power battery power supply mode. In the locomotive power supply scenario, the contact network power supply system usually uses a voltage level of 25kV for power supply. Figure 2 This is a schematic diagram of the main circuit topology of the hydrogen fuel hybrid locomotive of this embodiment 1.

[0041] like Figure 2As shown, because the output voltage of the hydrogen fuel cell stack is relatively low, a boost module DC / DC converter is configured in the circuit. By controlling the current or power value of the front-end input, the output voltage is stabilized at DC1800V. The high voltage output of the hydrogen fuel cell stack through the DC / DC converter is directly connected to the intermediate DC circuit of the traction converter. The output voltage of the power battery is directly connected to the intermediate DC circuit of the traction converter after passing through the line reactor, the first short-circuit pre-charging circuit and the chopper module. The 25kV high-voltage power supply is connected to the intermediate DC circuit of the traction converter after passing through the grid-side high-voltage circuit, the traction transformer, the second short-circuit pre-charging circuit and the traction converter four-quadrant converter. Among them, the first short-circuit pre-charging circuit includes a first output contactor and a first short-circuit contactor, the first output contactor and the first short-circuit contactor are connected in parallel, and one end of the first short-circuit contactor is connected to the first resistor; the second short-circuit pre-charging circuit includes a second output contactor and a second short-circuit contactor, the second output contactor and the second short-circuit contactor are connected in parallel, and one end of the second short-circuit contactor is connected to the second resistor.

[0042] like Figure 2 As shown, when the power battery is in the discharge state, the line reactor, the first output contactor of the first short-circuit pre-charging unit and the chopper module in the traction converter form a step-up chopper discharge circuit; the first output contactor of the first short-circuit pre-charging unit is automatically closed to charge the intermediate DC circuit, and the first short-circuit contactor is closed after the charging is completed. When the power battery is in the charging state, the line reactor, the first short-circuit contactor of the first short-circuit pre-charging unit and the chopper module in the traction converter form a step-down chopper charging circuit.

[0043] Compared with the traditional power battery direct charging circuit, the power battery charging circuit provided in this embodiment 1 is a step-down chopper controllable circuit, so that the charging voltage and current of the power battery are controllable. In the power battery power supply mode, that is, the power battery discharge state, the boost chopper discharge circuit boosts the output voltage of the power battery to DC1800V, and directly supplies power to the intermediate DC circuit of the traction inverter. In this embodiment 1, the power battery is a lithium battery. In the regenerative braking mode, the regenerative braking energy fed back by the traction motor is first charged to the lithium battery, and when the lithium battery cannot be charged, the braking resistor is used to consume the remaining energy. The main circuit provided in this embodiment 1 can smoothly switch between the power battery charging circuit and the braking resistor chopper circuit, thereby avoiding overcharging of the power battery or overvoltage failure of the intermediate voltage.

[0044] The switching process of the power battery charging circuit and the brake resistor chopper circuit is as follows: in the overhead power supply mode or when the locomotive is regeneratively braking, the power battery is charged by controlling the chopper bridge arm. When the power battery is high and the overvoltage protection is triggered, the step-down chopper charging circuit is immediately closed, and the intermediate voltage rises due to the closure of the charging circuit. When a certain threshold is reached, the chopper brake bridge arm is triggered, and the chopper brake bridge arm of the traction converter is turned on, and the locomotive puts the brake resistor into use to achieve the purpose of stabilizing the intermediate voltage.

[0045] Figure 1 This is a schematic diagram of the main circuit topology of a conventional hydrogen fuel hybrid locomotive. Figure 1 The power battery system shown is directly connected to the DC / DC output end of the hydrogen fuel power supply system. The main circuit provided in this embodiment 1 adds a chopper module in the traction inverter to form a boost chopper discharge circuit and a buck chopper charging circuit on the power battery side with the inductor, so that the voltage output from the power battery to the intermediate DC circuit is stabilized at DC1800V. At the same time, the stable and controllable charging circuit improves the circuit safety on the power battery side; the hydrogen fuel power supply module directly obtains the starting power supply from the intermediate DC circuit through the boost / buck module. After the hydrogen fuel power supply module is started, the stable intermediate DC circuit voltage can improve the stability and timeliness of the forward boost control of the boost / buck module.

[0046] Example 2

[0047] Embodiment 2 of the present invention provides a method for powering the main circuit of a hydrogen energy hybrid locomotive, including a power battery power supply mode, a hydrogen fuel hybrid power supply mode and a 25kV overhead line power supply mode:

[0048] 1. Power battery power supply mode:

[0049] When the power battery is in the discharging state: the chopper module in the traction inverter, the first output contactor of the first short-circuit pre-charging unit and the line inductor form a boost chopper discharge circuit, which boosts the output voltage of the power battery to DC1800V, outputs it to the intermediate DC circuit, and keeps it stable.

[0050] When the power battery is in charging state: the chopper module in the traction converter, the first short-circuit contactor of the first short-circuit pre-charging unit and the line reactor form a step-down chopper charging circuit. When the locomotive is in regenerative braking, the regenerative braking energy fed back by the traction motor is stepped down to charge the lithium battery. When the lithium battery cannot be charged, the braking resistor is used to consume the remaining energy, such as Figure 7 Energy flow shown by green arrows.

[0051] 2. Hydrogen fuel hybrid power supply mode:

[0052] Due to the starting characteristics of the hydrogen fuel cell stack, before the hydrogen fuel cell stack is started, the power battery first provides a DC1800V power supply to the intermediate DC circuit of the traction converter through the boost chopper discharge circuit, and the intermediate DC circuit reversely steps down the voltage through the DC / DC converter to provide the starting power supply to the hydrogen fuel cell stack. After the hydrogen fuel cell stack is started, the DC / DC converter stabilizes the forward boost output at DC1800V by controlling the current or power value of the front-end input.

[0053] When the hydrogen fuel system is shut down or in emergency, the power battery step-down chopper charging circuit and the brake resistor chopper circuit are turned on to consume the remaining energy output from the hydrogen fuel cell stack to the intermediate DC circuit. Figure 7 Energy flow shown by green arrows.

[0054] 3. 25kV contact network power supply mode:

[0055] The high-voltage power supply directly provides DC1800V power to the intermediate DC circuit through the primary high-voltage circuit, traction transformer, and traction converter four-quadrant converter, which is used to power auxiliary loads or charge power batteries, such as Figure 6 The energy flow is shown by the orange arrows in the figure. When the locomotive is in regenerative braking, the regenerative braking power at the axle end is used to charge the lithium battery first, making full use of the wheel energy and improving the regenerative performance of the system; when the lithium battery cannot absorb the energy, the remaining energy is directly fed back to the grid, and the braking resistor will not be started. Figure 7 Energy flow shown by purple arrows.

[0056] The power supply method provided in this embodiment 2 can ensure the voltage uniformity and stability of the intermediate DC circuit of the traction inverter under different power supply standards. At the same time, the stable intermediate DC circuit voltage helps to improve the high-voltage output stability of the DC / DC output end of the hydrogen fuel cell stack.

[0057] The supply voltage of the intermediate DC circuit can be selected according to the specific design of the traction converter, and can also be set to DC1850V or others.

[0058] This embodiment 2 integrates the main circuit of the overhead power supply system and the hydrogen fuel and power battery hybrid power supply system according to the structural characteristics of the locomotive overhead power supply circuit and the circuit structure characteristics of the hydrogen fuel hybrid power supply system. The main circuit integration design focuses on the circuit topology of the three-source power supply system, so that the energy is smoothly controlled in the main transmission system, and the consistency control of the intermediate voltage under different power supply modes is achieved, reducing the system failure caused by the inconsistency of the intermediate voltage of the same main transmission system under different power supply modes, and at the same time improving the high-voltage followability control accuracy of the output end of the hydrogen fuel system.

[0059] Example 3

[0060] An embodiment of the present invention further provides a rail vehicle, on which the hydrogen energy hybrid locomotive main circuit as described in Embodiment 1 is provided.

[0061] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the embodiments made by those skilled in the art fall within the scope defined by the claims attached to the present invention.

Claims

1. A main circuit of a hydrogen energy hybrid locomotive, characterized in that: The main circuit includes: a power battery module, a hydrogen fuel power supply module and a traction converter; The traction converter includes a first short-circuit pre-charging unit, a chopper module and an intermediate DC circuit; the output end of the power battery module is connected to the input end of the first short-circuit pre-charging unit through a reactor, and the output end of the first short-circuit pre-charging unit is connected to the intermediate DC circuit through the chopper module; The output end of the hydrogen fuel power supply module is connected to the intermediate DC circuit through a voltage step-up / step-down module.

2. The main circuit of the hydrogen energy hybrid locomotive according to claim 1 is characterized in that: The main circuit also includes a contact network power supply module; The traction converter also includes a second short-circuit pre-charging unit and a four-quadrant converter; The output end of the overhead power supply module is connected to the input end of the second short-circuit pre-charging unit, and the output end of the second short-circuit pre-charging unit is connected to the intermediate DC circuit through the four-quadrant converter.

3. The main circuit of the hydrogen energy hybrid locomotive according to claim 2 is characterized in that: The first short-circuit pre-charging unit comprises a first output contactor and a first short-circuit contactor, the first output contactor and the first short-circuit contactor are connected in parallel, and one end of the first short-circuit contactor is connected to a first resistor; And / or the second short-circuit pre-charging unit includes a second output contactor and a second short-circuit contactor, the second output contactor and the second short-circuit contactor are connected in parallel, and one end of the second short-circuit contactor is connected to a second resistor.

4. The main circuit of a hydrogen-powered hybrid locomotive according to any one of claims 1 to 3, characterized in that: The traction converter is also connected to a braking resistor, a traction motor and an auxiliary load respectively.

5. The main circuit of the hydrogen energy hybrid locomotive according to claim 4 is characterized in that: The braking resistor is connected to the intermediate DC circuit via a first DC / DC module; The traction motor is connected to the intermediate DC circuit via a first DC / AC module; The auxiliary load is connected to the intermediate DC circuit via a second DC / AC module.

6. The main circuit of the hydrogen energy hybrid locomotive according to claim 1 is characterized in that: The voltage step-up / step-down module is a DC / DC converter.

7. A method for powering the main circuit of a hydrogen energy hybrid locomotive according to claim 3, characterized in that: Including power battery power supply mode, hydrogen fuel hybrid power supply mode and overhead line power supply mode: In the power battery power supply mode: that is, when the power battery module is in the discharge state, the output voltage of the power battery module is boosted to DC1800V through the boost chopper discharge circuit to supply power to the intermediate DC circuit; In the hydrogen fuel hybrid power supply mode: before the hydrogen fuel power supply module is started, the power battery module first supplies power to the intermediate DC circuit through the boost chopper discharge circuit, and the intermediate DC circuit reversely steps down the voltage through the boost / step-down module to provide starting power to the hydrogen fuel power supply module; after the hydrogen fuel power supply module is started, the boost / step-down module forward boosts the voltage to stabilize the output voltage at DC1800V; in the contact network power supply mode: the contact network power supply module supplies power to the intermediate DC circuit, and the voltage is stabilized at DC1800V.

8. The method for powering the main circuit of a hydrogen energy hybrid locomotive according to claim 7, characterized in that: The traction converter is also connected to a braking resistor, a traction motor and an auxiliary load respectively; the power supply method further includes: In the power battery power supply mode: when the locomotive is in regenerative braking, the feedback energy generated by the traction motor is charged to the power battery module through the step-down chopper charging circuit, and when the power battery module cannot be charged, the remaining energy is consumed through the braking resistor; In the hydrogen fuel hybrid power supply mode: when the locomotive is in regenerative braking, the braking resistor chopper circuit and the step-down chopper charging circuit are turned on to consume the residual energy output from the hydrogen fuel power supply module to the intermediate DC circuit; In the overhead power supply mode: when the locomotive is in regenerative braking, the feedback energy generated by the traction motor is first used to charge the power battery module. When the power battery module cannot be charged, the remaining energy is returned to the overhead power supply module through the intermediate DC circuit. And / or the intermediate DC circuit power supply voltage is DC1850V.

9. A rail vehicle, characterized in that: The rail vehicle is provided with a hydrogen energy hybrid locomotive main circuit as claimed in any one of claims 1 to 6.

Images