Traction circuit for hybrid power supply of hydrogen fuel and power battery and control method

Abstract

The embodiment of the invention discloses a hydrogen fuel and power battery hybrid power supply traction circuit and a control method. The traction circuit comprises a hydrogen fuel battery, a power battery, a DC-DC device, a pre-charging loop, a supporting capacitor, a traction inverter, a traction motor, an auxiliary inverter and an auxiliary load. The hydrogen fuel cell is connected with the traction inverter and the auxiliary inverter through the DC-DC device; the support capacitor is connected in parallel between the positive and negative electrodes of the input ends of the traction inverter and the auxiliary inverter; the positive electrode of the output end of the power battery is connected with the positive electrodes of the input ends of the traction inverter and the auxiliary inverter through the pre-charging loop, the negative electrode of the output end of the power battery is connected with the negative electrodes of the input ends of the traction inverter and the auxiliary inverter, the output end of the traction inverter is connected with the traction motor, and the output end of the auxiliary inverter is connected with the auxiliary load. By means of the mode, the topology complexity can be optimized, the reliability and economical efficiency of the system are improved, and meanwhile the size, weight and cost of the system are greatly reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of rail transit technology, and specifically to a traction circuit and a control method for hybrid power supply of hydrogen fuel and power batteries. Background Art

[0002] Due to environmental protection and other requirements, the diesel engine-driven shunting locomotives traditionally used in non-electrified railways are facing replacement. Currently, the most popular combination is hydrogen fuel + power battery. Hydrogen fuel has a low output voltage and slow output power changes due to the inactivity of the reactor. It is not suitable to be used as a power source to drive rail vehicles alone. Usually, it is supplemented by power batteries with energy storage.

[0003] In traditional hydrogen fuel circuits, in order to take into account the characteristics of low fuel stack output voltage and slow power change, a DC-DC device is used to stabilize the fuel stack output voltage, and another DC-DC device is used to stabilize the power battery output voltage. The two DC-DC devices achieve stable output through the output power characteristics of the interactive power supply. This not only indirectly causes problems such as high cost and complex control, but also reduces vehicle availability. For example, if the power battery DC-DC device is damaged and short-circuited, the entire vehicle cannot be towed by relying solely on the hydrogen fuel power output, which is not conducive to the operation of rail vehicles. Summary of the invention

[0004] In view of the above problems, an embodiment of the present invention provides a traction circuit and a control method for hybrid power supply of hydrogen fuel and power battery, which overcomes the above problems or at least partially solves the above problems.

[0005] According to one aspect of an embodiment of the present invention, a traction circuit powered by a combination of hydrogen fuel and a power battery is provided, comprising: a hydrogen fuel cell, a power battery, a DC-DC device, a pre-charging circuit, a support capacitor, a traction inverter, a traction motor, an auxiliary inverter and an auxiliary load; the hydrogen fuel cell is connected to the DC-DC device, the output end of the DC-DC device is connected to the traction inverter and the auxiliary inverter, the support capacitor is connected in parallel between the positive and negative electrodes of the input ends of the traction inverter and the auxiliary inverter; the positive electrode of the output end of the power battery is connected to the pre-charging circuit, the output end of the pre-charging circuit is connected to the positive electrode of the input end of the traction inverter and the auxiliary inverter, the negative electrode of the output end of the power battery is connected to the negative electrode of the input end of the traction inverter and the auxiliary inverter, the output end of the traction inverter is connected to the traction motor, and the output end of the auxiliary inverter is connected to the auxiliary load.

[0006] Optionally, the traction circuit further includes: a DC voltage detection system, wherein the DC voltage detection system is connected in parallel to both ends of the support capacitor.

[0007] Optionally, the traction circuit further includes: an in-storage power supply, an output end of the in-storage power supply is connected to input ends of the traction inverter and the auxiliary inverter.

[0008] Based on the same inventive concept, a control method for hybrid power supply of hydrogen fuel and power battery is provided, the method comprising: under starting condition, pre-charging is performed through the power battery, and then the power battery or the fuel cell is controlled to start alone; under traction condition, the output power of the hydrogen fuel cell is adjusted according to the required power and the detected real-time power of the power battery; under braking condition, the traction motor is controlled to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power.

[0009] Optionally, the method further includes: when the in-store power supply is supplying power, pre-charging is performed through the power battery; after the pre-charging is completed, controlling the in-store power supply to charge the power battery.

[0010] Optionally, before the pre-charging through the power battery, it includes: receiving a handshake request signal from the power supply in the warehouse; before the controlling the power supply in the warehouse to charge the power battery, it includes: using the power battery to pre-charge the power battery through an intermediate circuit; after the pre-charging is completed, feeding back a preparation completion signal to the power supply in the warehouse.

[0011] Optionally, adjusting the output power of the hydrogen fuel cell according to the required power and the detected real-time power of the power battery includes: controlling the output voltage of the power battery to be the DC voltage of the intermediate circuit; comparing the sum of the allowed output power of the battery management system and the real-time output power of the hydrogen fuel cell with the required power; and adjusting the real-time output power of the hydrogen fuel cell and / or the output power of the power battery according to the comparison result.

[0012] Optionally, adjusting the real-time output power of the hydrogen fuel cell and / or the output power of the power battery according to the comparison result includes:

[0013] If the required power is less than or equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is increased at an accelerated rate until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell; if the required power is greater than the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery and the real-time output power of the hydrogen fuel cell are increased at the same time until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell.

[0014] Optionally, the simultaneous increasing of the output power of the power battery and the real-time output power of the hydrogen fuel cell until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell includes: accelerating the increase of the output power of the power battery until the output power of the power battery is equal to the allowable output power of the power battery; outputting control instructions to control the increase of the real-time output power of the hydrogen fuel cell until the required power is equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell.

[0015] Optionally, the controlling the traction motor to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power includes: controlling the traction motor to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the power supply voltage; controlling the traction motor to continue to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the maximum charging power or the traction motor reaches the maximum braking power.

[0016] The traction circuit for hybrid power supply of hydrogen fuel and power battery in the embodiment of the present invention includes: a hydrogen fuel cell, a power battery, a DC-DC device, a pre-charging circuit, a support capacitor, a traction inverter, a traction motor, an auxiliary inverter and an auxiliary load; the hydrogen fuel cell is connected to the DC-DC device, the output end of the DC-DC device is connected to the traction inverter and the auxiliary inverter, and the support capacitor is connected in parallel between the positive and negative electrodes of the input ends of the traction inverter and the auxiliary inverter; the positive electrode of the output end of the power battery is connected to the pre-charging circuit, the output end of the pre-charging circuit is connected to the positive electrode of the input end of the traction inverter and the auxiliary inverter, the negative electrode of the output end of the power battery is connected to the negative electrode of the input end of the traction inverter and the auxiliary inverter, the output end of the traction inverter is connected to the traction motor, and the output end of the auxiliary inverter is connected to the auxiliary load, which can optimize the topological complexity, improve the system reliability and economy, and greatly reduce the system volume, weight and cost.

[0017] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 A schematic diagram of the structure of a traction circuit powered by a combination of hydrogen fuel and a power battery provided in an embodiment of the present invention is shown;

[0020] Figure 2 A schematic flow chart showing a method for controlling a hybrid power supply of hydrogen fuel and a power battery according to an embodiment of the present invention is shown;

[0021] Figure 3 A control block diagram of a hydrogen fuel and power battery hybrid power supply according to an embodiment of the present invention is shown;

[0022] Figure 4 A schematic diagram of a complete control process under traction and braking conditions of an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0024] Figure 1 The structure diagram of the traction circuit provided by the embodiment of the present invention is shown. Figure 1As shown, the traction circuit powered by a combination of hydrogen fuel and power batteries includes: a hydrogen fuel cell 1, a power battery 2, a DC-DC device 4, a pre-charging circuit 7, a support capacitor 10, a traction inverter 11, a traction motor 13, an auxiliary inverter 12 and an auxiliary load 14. The hydrogen fuel cell 1 is connected to the DC-DC device 4, the output end of the DC-DC device 4 is connected to the traction inverter 11 and the auxiliary inverter 12, and the support capacitor 10 is connected in parallel between the positive and negative electrodes of the input ends of the traction inverter 11 and the auxiliary inverter 12; the positive electrode of the output end of the power battery 2 is connected to the pre-charging circuit 7, the output end of the pre-charging circuit 7 is connected to the positive electrode of the input end of the traction inverter 11 and the auxiliary inverter 12, the negative electrode of the output end of the power battery 2 is connected to the negative electrode of the input end of the traction inverter 11 and the auxiliary inverter 12, the output end of the traction inverter 11 is connected to the traction motor 13, and the output end of the auxiliary inverter 12 is connected to the auxiliary load 14.

[0025] The traction circuit also includes: a DC voltage detection system 9, which is connected in parallel to both ends of the support capacitor 10. The traction circuit also includes: an in-store power supply 3, the output end of which is connected to the input end of the traction inverter 11 and the auxiliary inverter 12. The pre-charging circuit 7 includes a first relay K1, a second relay K2 and a resistor R. The second relay K2 and the resistor R are connected in series and in parallel to both ends of the first relay K1. The positive pole of the output end of the power battery 2 is connected to one end of the first relay K1, and the other end of the first relay K1 is connected to the positive pole of the input end of the traction inverter 11, and is also connected to the positive pole of the input end of the auxiliary inverter 12.

[0026] Under the starting condition, the hydrogen fuel cell 1 cannot be started alone, and the power battery 2 must be started first. After pre-charging, the hydrogen fuel cell 1 stack starts to output power after being boosted by the DC-DC device 4. This avoids the impact of the DC circuit capacitor caused by the excessive starting voltage of the DC-DC device 4 of the hydrogen fuel cell 1.

[0027] Under traction conditions, the output voltage U of the power battery 2 bat Equal to DC voltage U dc The hydrogen fuel cell 1 is boosted and output by the DC-DC device 4, and its output power P out1 Equal to the fuel pile reaction power P H , that is, the DC-DC device 4 supporting the hydrogen fuel cell 1 outputs with power control as the target. At this time, when the traction inverter 11 and the auxiliary inverter 12 draw power from the intermediate circuit, the total power of the intermediate circuit is P DC =P INV +P AINV , the output power P of power battery 2 out2=P DC -P out1 , forming an effective power closed loop.

[0028] Under braking conditions, the traction motor 13 charges the intermediate circuit through the traction inverter 11. At this time, the DC voltage U set2 The braking torque envelope is determined by the battery management system (BMS) corresponding to the power battery. During the actual braking process, the traction inverter 11 feeds back the voltage to the intermediate circuit at the power battery power voltage U bat As the initial target, the feedback voltage is gradually raised. If the maximum braking power is reached first, the feedback voltage is stopped if the motor has output the maximum braking torque according to the vehicle envelope. If the maximum charging voltage is reached first, that is, according to the real-time maximum charging voltage transmitted by the BMS system, the feedback voltage is stopped; that is, the traction inverter 11 outputs a variable charging voltage as the target, and observes in real time to ensure that the real-time charging power should not be greater than the maximum braking power, and the real-time braking power should not be greater than the maximum charging power. At this time, the electric energy generated by the braking kinetic energy recovery will be used to charge the power battery 2. When the power battery 2 is full of electricity, the energy recovery of the traction motor 13 is stopped, and the vehicle loses the electric braking force.

[0029] Before the in-store power supply 3 is input to the intermediate circuit, it must first shake hands with the traction control unit. After receiving the handshake request, the traction control unit first starts the pre-charging circuit 7 of the power battery 2. The energy consumption of this charging process is extremely small, and since the power battery 2 has a minimum power limit, there is no need to consider the situation where the power battery 2 is exhausted and cannot be charged. After the pre-charging is completed, the output contactor of the power battery 2 is disconnected, and the preparation completion signal is fed back to the in-store power supply 3. The in-store power supply 3 starts to output voltage, completing the preparation before charging the power battery 2.

[0030] The embodiment of the present invention cancels the DC-DC device of the power battery and its supporting chopper inductor. The output power of the power battery 2 will no longer be limited by the chopper inductor capacity, which greatly improves the output capacity of the power battery. At the same time, due to the cancellation of the DC-DC link, the efficiency of the power battery output (there is diode power loss through the DC-DC device) and charging (there is switching loss in the step-down process through the DC-DC device) is improved. At the same time, the cancellation of the DC-DC device and the inductor can also greatly reduce the system volume, weight and cost, optimize the topological complexity, and improve the system reliability and economy. The embodiment of the present invention also fully considers the characteristics that the output power of the hydrogen fuel cell 1 is small and cannot be used as a traction power supply alone, cancels the pre-charging circuit output by the hydrogen fuel cell 1, and by adjusting the starting sequence, the topological complexity is reduced without affecting the system function, and the system reliability is improved; at the same time, the input logic of the power supply 3 in the warehouse is optimized, and the pre-charging circuit of the power supply 3 in the warehouse is cancelled, which reduces the topological complexity and improves the system reliability.

[0031] Based on the same concept, the embodiment of the present invention also provides a control method for hybrid power supply of hydrogen fuel and power battery, such as Figure 2 As shown, the control method for hybrid power supply of hydrogen fuel and power battery is applied to a traction control unit (TCU), and the method includes:

[0032] Step S11: Under the starting condition, pre-charge the power battery, and then control the power battery or the fuel cell to start the engine alone.

[0033] Under starting conditions, the hydrogen fuel cell cannot be started alone. Therefore, the power battery is used to start the machine first, and the supporting capacitor is precharged through the pre-charging circuit. After pre-charging, the hydrogen fuel cell stack starts to output power after being boosted by the DC-DC device. This avoids the impact of the excessive starting voltage of the hydrogen fuel cell DC-DC device on the DC circuit capacitor. In this way, the embodiment of the present invention fully considers the characteristics of the hydrogen fuel cell that the output power is small and cannot be used as a traction power supply alone, cancels the pre-charging circuit of the hydrogen fuel cell output, and reduces the topological complexity and improves the system reliability without affecting the system function by adjusting the starting sequence.

[0034] Step S12: Under traction conditions, the output power of the hydrogen fuel cell is adjusted according to the required power and the detected real-time power of the power battery.

[0035] In the embodiment of the present invention, the control block diagram of the hybrid power supply of hydrogen fuel and power battery is as follows: Figure 3 As shown, the traction controller TCU receives the power demand transmitted by the traction handle and obtains the required power P. The traction controller TCU simultaneously obtains the allowed output power P1 and real-time voltage of the battery management system BMS, and the allowed power of the hydrogen fuel cell, and obtains the real-time power of the BMS according to the real-time voltage of the BMS. The traction controller TCU adjusts the real-time output power of the hydrogen fuel cell HMS in real time according to the real-time power P1 and the required power P of the BMS.

[0036] Specifically, in step S12, optionally, the power battery output voltage U is controlled bat is the DC voltage U of the intermediate circuit dc ; Compare the sum of the allowed output power of the battery management system and the real-time output power of the hydrogen fuel cell with the required power; and adjust the real-time output power of the hydrogen fuel cell and / or the output power of the power battery according to the comparison result.

[0037] In the embodiment of the present invention, if the required power is less than or equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is increased at an accelerated rate until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell. If the required power is greater than the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery and the real-time output power of the hydrogen fuel cell are increased simultaneously until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell.

[0038] The complete control process under traction and braking conditions is as follows Figure 4 As shown. Under traction conditions, first determine whether the required power P is greater than the sum of the allowable output power P1 of the power battery and the real-time output power P2 of the hydrogen fuel cell. If the required power is less than or equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is increased until the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell is equal to the required power.

[0039] If the required power is greater than the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is accelerated until the output power of the power battery is equal to the allowable output power of the power battery; then a control instruction is output to control the increase of the real-time output power of the hydrogen fuel cell until the required power is equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell. That is, if the required power is greater than the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is accelerated until the output power of the power battery is equal to the allowable output power of the power battery. At the same time, the traction controller TCU outputs a control instruction to control the hydrogen fuel cell to increase the real-time output power P2. In the process of increasing the output power of the power battery and the real-time output power P2 of the hydrogen fuel cell, it is detected whether the total real-time power P3 output by the power battery and the hydrogen fuel cell is equal to the sum of the allowable output power P1 of the power battery and the real-time output power P2 of the hydrogen fuel cell. If not, the output power of the power battery is accelerated until the output power of the power battery is equal to the allowable output power of the power battery. If so, it means that the output power of the power battery is equal to the allowable output power of the power battery. At this time, the slow acceleration mode is entered, that is, the real-time output power P2 of the hydrogen fuel cell is slowly increased until the sum of the allowable output power P1 of the power battery and the real-time output power P2 of the hydrogen fuel cell is equal to the required power P.

[0040] At this point, the power distribution between the power battery and the hydrogen fuel cell is completed. At this point, the power battery output voltage U bat Equal to DC voltage U dcThe hydrogen fuel cell is boosted by a DC-DC device, and its output power P out1 Equal to the fuel pile reaction power P H , that is, the DC-DC device supporting the hydrogen fuel cell outputs power control as the target. When the traction inverter and the auxiliary inverter draw power from the intermediate DC circuit, the total power of the DC circuit P DC =P INV +P AINV , power battery output power P out2 =P DC -P out1 , forming an effective power closed loop. Since the output of the power battery in the prior art has diode power loss and switching loss in the step-down process when passing through the DC-DC device, the embodiment of the present invention cancels the DC-DC device of the power battery and its supporting chopper inductor, and the output power of the power battery will no longer be limited by the capacity of the chopper inductor, which greatly improves the output capacity of the power battery. At the same time, due to the cancellation of the DC-DC link, the efficiency of power battery output and charging is improved. At the same time, the cancellation of the DC-DC device and inductor can also greatly reduce the system volume, weight and cost, optimize the topology complexity, and improve the system reliability and economy.

[0041] Step S13: Under braking conditions, the traction motor is controlled to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power.

[0042] In an embodiment of the present invention, optionally, the traction motor is controlled to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the power supply voltage; the traction motor is controlled to continue to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the maximum charging power or the traction motor reaches the maximum braking power.

[0043] Under braking conditions, the traction motor charges the intermediate circuit through the traction inverter. At this time, the set DC voltage Uset is determined by the BMS system and the braking torque envelope. During the actual braking process, the traction inverter feeds back the intermediate DC voltage with Ubat as the initial target and gradually increases the feedback voltage. Figure 4 , determine the maximum braking power P of the traction motor max The maximum charging voltage of the BMS system is determined, and the feedback voltage of the traction motor through the intermediate circuit is determined as Uset = Ubat + ΔU, where ΔU is the increased feedback voltage. The traction controller gradually increases the ΔU value and determines that the braking power of the traction motor is greater than P max , or whether the total feedback voltage Uset is greater than the maximum charging voltage U max If the braking power of the traction motor is greater than P max , or the total feedback voltage Uset is greater than the maximum charging voltage Umax , the current feedback voltage remains unchanged. Otherwise, the ΔU value continues to increase. At this time, the electric energy generated by the braking kinetic energy recovery will be used to charge the power battery. When the power battery is fully charged, the energy recovery of the traction motor is stopped, and the vehicle loses the electric braking force.

[0044] In an embodiment of the present invention, the vehicle enters the garage and is powered by the power supply in the garage. In this way, the control method for hybrid power supply of hydrogen fuel and power battery also includes: when the power supply in the garage is powered, pre-charging is performed through the power battery; after the pre-charging is completed, the power supply in the garage is controlled to charge the power battery. In addition, before pre-charging through the power battery, a handshake request signal of the power supply in the garage is received; after the traction controller receives the handshake request signal, the pre-charging circuit of the power battery is started to pre-charge the support capacitor. Before pre-charging through the power battery, the power battery is pre-charged to the power battery through the intermediate circuit; after the pre-charging is completed, the preparation completion signal is fed back to the power supply in the garage. More specifically, before the power supply in the garage is input to the intermediate circuit, it is necessary to handshake with the traction control unit first. After the traction controller receives the handshake request signal, the traction control unit first starts the pre-charging circuit of the power battery to pre-charge the support capacitor. After the pre-charging is completed, the power battery output contactor is disconnected, and the preparation completion signal is fed back to the power supply in the garage. Then the power supply in the garage starts to output voltage to complete the preparation before charging the power battery. It should be noted that the energy consumption of the charging process here is extremely small, and since the power battery has a minimum power limit, there is no need to consider the situation where the power battery is exhausted and cannot be charged. The embodiment of the present invention cancels the pre-charging circuit of the power input in the warehouse, optimizes the power input logic in the warehouse, reduces the topology complexity, and improves the system reliability.

[0045] In summary, the control method for hybrid power supply of hydrogen fuel and power battery in the embodiment of the present invention designs a set of power closed-loop management logic that meets the starting, traction and braking conditions, which can meet the vehicle operation needs. Under the starting condition, the power battery is pre-charged, and then the power battery or fuel cell is controlled to start alone; under the traction condition, the output power of the hydrogen fuel cell is adjusted according to the required power and the detected real-time power of the power battery; under the braking condition, the traction motor is controlled to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power. It can optimize the topological complexity, improve the system reliability and economy, and greatly reduce the system volume, weight and cost.

[0046] The above specific embodiments of the present invention are described. In some cases, the actions or steps recorded in the embodiments of the present invention can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0047] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0048] This application is intended to cover all such substitutions, modifications and variations that fall within the broad scope of all embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of this disclosure.

Claims

1. A traction circuit powered by a combination of hydrogen fuel and power batteries, characterized in that: The traction circuit includes: a hydrogen fuel cell, a power battery, a DC-DC device, a pre-charging circuit, a support capacitor, a traction inverter, a traction motor, an auxiliary inverter and an auxiliary load; the hydrogen fuel cell is connected to the DC-DC device, the output end of the DC-DC device is connected to the traction inverter and the auxiliary inverter, and the support capacitor is connected in parallel between the positive and negative electrodes of the input ends of the traction inverter and the auxiliary inverter; the positive electrode of the output end of the power battery is connected to the pre-charging circuit, the output end of the pre-charging circuit is connected to the positive electrode of the input end of the traction inverter and the auxiliary inverter, the negative electrode of the output end of the power battery is connected to the negative electrode of the input end of the traction inverter and the auxiliary inverter, the output end of the traction inverter is connected to the traction motor, and the output end of the auxiliary inverter is connected to the auxiliary load.

2. The traction circuit according to claim 1, characterized in that: The traction circuit further includes: a DC voltage detection system, which is connected in parallel to both ends of the support capacitor.

3. The traction circuit according to claim 1, characterized in that: The traction circuit further includes: an in-storage power supply, the output end of which is connected to the input ends of the traction inverter and the auxiliary inverter.

4. A control method for hybrid power supply of hydrogen fuel and power battery, characterized in that: The method comprises: Under the starting condition, the power battery is pre-charged, and then the power battery or fuel cell is controlled to start the engine alone; Under traction conditions, the output power of the hydrogen fuel cell is adjusted according to the required power and the detected real-time power of the power battery; Under braking conditions, the traction motor is controlled to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power.

5. The method according to claim 4, characterized in that The method further comprises: When the power supply in the warehouse is used, the power battery is used for pre-charging; After pre-charging is completed, the power supply in the control warehouse is controlled to charge the power battery.

6. The method according to claim 5, characterized in that Before the pre-charging is performed by the power battery, the method includes: receiving a handshake request signal from the power supply in the warehouse; Before controlling the power supply in the depot to charge the power battery, the method includes: using the power battery to pre-charge the power battery through the intermediate circuit; and after the pre-charging is completed, feeding back a preparation completion signal to the power supply in the depot.

7. The method according to claim 4, characterized in that The method of adjusting the output power of the hydrogen fuel cell according to the required power and the detected real-time power of the power battery includes: Control the power battery output voltage to be the DC voltage of the intermediate circuit; comparing the sum of the allowed output power of the battery management system and the real-time output power of the hydrogen fuel cell with the required power; The real-time output power of the hydrogen fuel cell and / or the output power of the power battery is adjusted according to the comparison result.

8. The method according to claim 7, characterized in that: The step of adjusting the real-time output power of the hydrogen fuel cell and / or the output power of the power battery according to the comparison result includes: If the required power is less than or equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery is increased at an accelerated rate until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell; If the required power is greater than the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell, the output power of the power battery and the real-time output power of the hydrogen fuel cell are increased simultaneously until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell.

9. The method according to claim 8, characterized in that: The step of simultaneously increasing the output power of the power battery and the real-time output power of the hydrogen fuel cell until the required power is equal to the sum of the output power of the power battery and the real-time output power of the hydrogen fuel cell includes: Accelerate the increase of the output power of the power battery until the output power of the power battery is equal to the allowable output power of the power battery; The output control instruction controls the increase of the real-time output power of the hydrogen fuel cell until the required power is equal to the sum of the allowable output power of the power battery and the real-time output power of the hydrogen fuel cell.

10. The method according to claim 4, characterized in that: The controlling the traction motor to gradually increase the feedback voltage through the intermediate circuit until the maximum charging power of the power battery is reached or the traction motor reaches the maximum braking power includes: Control the traction motor to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the power supply voltage; The traction motor is controlled to continue to gradually increase the feedback voltage through the intermediate circuit until the real-time charging voltage of the power battery reaches the maximum charging power or the traction motor reaches the maximum braking power.

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