New energy automobile hybrid power system

Abstract

The invention discloses a hybrid power system of a new energy automobile, belongs to the technical field of new energy automobiles, and solves the technical problem of poor stability caused by the fact that the response speed of a fuel cell lags behind load change. The system comprises a battery management system, a hydrogen fuel cell power supply system, a power monitoring device, a bidirectional direct current rectifier, a power battery system, a control module, a power battery charger, a traction inverter, a traction motor, an auxiliary inverter, a chopping module and a brake resistor. When the automobile is started, the control module controls the power battery system to provide all starting electric energy; during driving, the output of the hydrogen fuel cell power supply system is stable, and the control module controls the hydrogen fuel cell power supply system to gradually replace the power cell system for output; and when the vehicle runs to a relatively stable stage, the control module judges to perform energy recovery or independent power supply of the hydrogen fuel cell power supply system or combined power supply of the hydrogen fuel cell power supply system and the power battery system according to the speed and the torque.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and more specifically, to a hybrid power system for new energy vehicles. Background Art

[0002] With the increase of global energy consumption and the intensification of environmental pollution pressure, new energy vehicle technology has become a research hotspot. Fuel cells are a power generation device based on electrochemical reactions. They have great potential for future development, high energy conversion efficiency, and pollution-free operation. They have been put into use in some scenarios.

[0003] For the new energy industry, the development of fuel cells and related hydrogen production and storage technologies will become a focus of attention. Fuel cells are expected to be widely used in engineering machinery, power and other fields in the future. The characteristics of the reaction gas in hydrogen fuel cells determine the hysteresis of their response. The complex and changeable working conditions of engineering machinery will cause the response speed of the fuel cell to lag behind the load change, resulting in frequent "gas starvation" phenomena, which will affect the durability and stability of the entire fuel cell system. Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art, and an object of the present invention is to provide a new energy vehicle hybrid power system with good stability.

[0005] The technical solution of the present invention is: a hybrid power system for new energy vehicles, including a battery management system, a hydrogen fuel cell power supply system, a power monitoring device, a bidirectional DC rectifier, a power battery system, a control module, a power battery charger, a traction inverter, a traction motor, an auxiliary inverter, a chopper module, and a brake resistor;

[0006] The hydrogen fuel cell power supply system is electrically connected to the power monitoring device, the bidirectional DC rectifier, and the control module in sequence; the power battery system is electrically connected to the control module; the control module is electrically connected to the traction motor through the traction inverter; the control module is electrically connected to the auxiliary load through the auxiliary inverter; the traction inverter and the auxiliary inverter are both electrically connected to the brake resistor through the chopper module; the traction inverter and the auxiliary inverter are both electrically connected to the power battery system through the power battery charger; the battery management system is electrically connected to the power monitoring device, the control module, and the power battery system; the control module is also electrically connected to the traction motor;

[0007] The working process of the hybrid power system includes the following steps:

[0008] Step 1. The vehicle starts, at which time the vehicle speed V is 0 and the torque is T0, and the control module controls the power battery system to provide all the starting power;

[0009] Step 2. As the vehicle is driving, the control module determines whether the output of the hydrogen fuel cell power supply system is stable through the power monitoring device; if it is not stable, the vehicle will continue to drive for a set time and then make another determination; if it is stable, the control module controls the hydrogen fuel cell power supply system to gradually replace the power battery system for output;

[0010] Step 3. When the vehicle reaches a relatively stable stage, the control module determines whether to perform energy recovery or the hydrogen fuel cell power supply system to supply power alone or the hydrogen fuel cell power supply system and the power battery system to supply power jointly according to the current speed V and the current torque T.

[0011] As a further improvement, determining whether the output of the hydrogen fuel cell power supply system is stable by the power monitoring device is as follows: after the hydrogen fuel cell power supply system responds, recording the output power P at the xth second x , the power P at (x+1) seconds x+1 , using the formula (P x+1 -P x ) / P x Determine P x+1 Compared to P x If the rate of change is within the set range, the output of the hydrogen fuel cell power supply system is stable; otherwise, the output of the hydrogen fuel cell power supply system is unstable, waiting for the next determination.

[0012] Furthermore, the setting variation range is ±5%.

[0013] Furthermore, the set time is 3 to 5 minutes.

[0014] Furthermore, in step 3, if the current speed V increases and the current torque T decreases, it means that power output is not needed at this time, and energy will be recovered. The recovery process first passes through the battery management system to determine the SOC of the power battery system. Energy recovery is only performed when the charge is between 5% and 95% to ensure the service life of the power battery.

[0015] Further, in step 3, if the current speed V decreases and the current torque T increases, a braking determination is performed; if braking is performed, energy is recovered; otherwise, the output power required by the vehicle increases, and the hydrogen fuel cell power supply system is controlled to increase output;

[0016] When P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system and the power battery system need to jointly output power; otherwise P出 =P H2 , only the hydrogen fuel cell power supply system needs to output power; P 出 Indicates the output power required by the car, P H2max represents the maximum output power of the hydrogen fuel cell power supply system, P 动 Indicates the output power required by the power battery system, P H2 Represents the output power of the hydrogen fuel cell power supply system.

[0017] Further, in step 3, if the accelerator pedal is used, and the current speed V increases and the current torque T increases; when P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system and the power battery system need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system needs to output power.

[0018] Furthermore, the relatively stable stage is when the speed of the car reaches 10Km / h.

[0019] Furthermore, the bidirectional DC rectifier supports smart grid and V2G technology.

[0020] Furthermore, the control module optimizes the output power P required by the vehicle through a particle swarm algorithm based on the speed, torque and time information and takes low fuel consumption as the optimization goal. 出 And the output power P of the hydrogen fuel cell power supply system H2 .

[0021] Beneficial Effects

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention can improve the problem of slow response and soft output characteristics of hydrogen fuel cell during the start-up process of the car, and at the same time determine the output stability of the hydrogen fuel cell to ensure the stability of the car's driving.

[0024] 2. The present invention adopts speed, torque, and time information, takes low fuel consumption as the optimization goal, and optimizes the output power required by the automobile and the output power of the hydrogen fuel cell power supply system through the particle swarm algorithm. The control method is relatively simple and has low data accuracy requirements, which can avoid related problems caused by high-precision requirements. At the same time, it can judge some situations during driving and deal with uncertain conditions or disturbances well.

[0025] 3. The present invention performs energy recovery. First, the SOC of the power battery is determined through the BMS to ensure the safety of the power battery. At the same time, a power battery charger, a chopper module, and a brake resistor are additionally added for charging the power battery to further protect the safety of the power battery.

[0026] 4. The present invention recovers energy to a great extent, reduces energy loss, and thus reduces fuel consumption and increases vehicle mileage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural diagram of the present invention;

[0028] Figure 2 It is a logic diagram for determining the stability of the hydrogen fuel cell power supply system;

[0029] Figure 3 This is the schematic diagram of braking energy recovery;

[0030] Figure 4 Power supply control schematic diagram for hydrogen fuel cell power supply system and power battery system.

[0031] Among them: 1- hydrogen fuel cell power supply system, 2- power monitoring device, 3- bidirectional DC rectifier, 4- power battery system, 5- control module, 6- power battery charger, 7- traction inverter, 8- auxiliary inverter, 9- chopper module, 10- brake resistor, 11- auxiliary load, BMS- battery management system, TM- traction motor. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0033] See also Figure 1 to Figure 4 A hybrid power system for a new energy vehicle includes a battery management system BMS, a hydrogen fuel cell power supply system 1, a power monitoring device 2, a bidirectional DC rectifier 3, a power battery system 4, a control module 5, a power battery charger 6, a traction inverter 7, a traction motor TM, an auxiliary inverter 8, a chopper module 9, and a braking resistor 10.

[0034] The hydrogen fuel cell power supply system 1 is electrically connected to the power monitoring device 2, the bidirectional DC rectifier 3, and the control module 5 in sequence. The power battery system 4 is electrically connected to the control module 5. The control module 5 is electrically connected to the traction motor TM through the traction inverter 7. The control module 5 is electrically connected to the auxiliary load 11 through the auxiliary inverter 8. The traction inverter 7 and the auxiliary inverter 8 are both electrically connected to the braking resistor 10 through the chopper module 9. The traction inverter 7 and the auxiliary inverter 8 are both electrically connected to the power battery system 4 through the power battery charger 6. The battery management system BMS is electrically connected to the power monitoring device 2, the control module 5, and the power battery system 4. The control module 5 is also electrically connected to the traction motor TM.

[0035] The battery management system BMS is mainly responsible for measuring the battery terminal voltage, balancing the energy between single cells, estimating the state of charge and health, limiting the power input and output, controlling the charging curve, and isolating the battery pack from the load.

[0036] The hydrogen fuel cell power supply system 1 is a power generation device system that directly converts hydrogen and oxygen into electrical energy through electrochemical reactions, and is the main energy source of the power system.

[0037] The power battery system 4 is an auxiliary power system to compensate for the slow response and soft output characteristics of the hydrogen fuel cell power supply system 1, as well as some sudden operating conditions.

[0038] The power monitoring device 2 determines whether the output is stable by monitoring the output power of the hydrogen fuel cell power supply system 1. When the power fluctuates or decreases significantly, the device will sound an alarm to indicate that there may be a problem with the fuel cell.

[0039] like Figure 2 As shown, the power monitoring device 2 is used to determine whether the output of the hydrogen fuel cell power supply system 1 is stable. Specifically, after the hydrogen fuel cell power supply system 1 responds, the output power P at the xth second is recorded. x , the power P at (x+1) seconds x+1 , using the formula (P x+1 -P x ) / P x Determine P x+1 Compared to P x If the change rate is within the set change range, the output of the hydrogen fuel cell power supply system 1 is stable, otherwise the output of the hydrogen fuel cell power supply system 1 is unstable, waiting for the next judgment. In this embodiment, the set change range is ±5%.

[0040] The bidirectional DC rectifier 3 can not only convert AC power into DC power to provide a stable power supply for the load, but also invert DC power into AC power to realize energy feedback. In the renewable energy power generation system, the bidirectional DC rectifier can adjust the flow and size of electric energy, ensure the stable operation of the power grid, and improve energy utilization efficiency. At the same time, it also supports smart grid and V2G (Vehicle to Grid) technology, realizes the interaction between electric vehicles and the power grid, and provides auxiliary services for the power grid. In addition, the bidirectional DC rectifier also has a variety of protection functions to ensure the safe operation of the power grid and equipment.

[0041] The traction inverter 7 is used to drive the traction motor TM and also takes into account energy conversion, regulation control, system detection and protection.

[0042] The traction motor TM is used to drive the wheels of the vehicle to rotate.

[0043] The auxiliary inverter 8 is used to provide stable power to various auxiliary loads 11 (such as vehicle computers, vehicle lights, external speakers, etc.).

[0044] The brake resistor 10 is a high-power resistor or brake resistor, which is a kind of corrugated resistor. It is mainly used in the mechanical system where the inverter controls the motor to stop quickly, helping the motor to convert the regenerative electric energy generated by the fast stop into heat energy, thereby protecting the inverter and ensuring the smooth operation of the power supply network.

[0045] The chopper module 9 is used for power conversion and motor control to ensure stable operation of the system, improve overall efficiency, and meet specific application requirements.

[0046] The power battery charger 6 is used to ensure safe and efficient charging of the power battery by accurately controlling and managing the charging process.

[0047] The working process of the hybrid system includes the following steps 1 to 3:

[0048] Step 1. The vehicle starts. At this time, the vehicle speed V is 0, the torque is T0, and the control module 5 controls the power battery system 4 to provide all the starting power; that is, the power battery is used first to start the vehicle.

[0049] Step 2. As the vehicle is driving, the control module 5 determines whether the output of the hydrogen fuel cell power supply system 1 is stable through the power monitoring device 2 .

[0050] If it is unstable, the vehicle will continue to travel for a set time, such as 3 to 5 minutes, before making a judgment.

[0051] If stable, the control module 5 controls the hydrogen fuel cell power supply system 1 to gradually replace the power battery system 4 for output. That is, the output power of the hydrogen fuel cell power supply system 1 gradually increases, and the output power of the power battery system 4 gradually decreases to 0.

[0052] Step 3. When the vehicle reaches a relatively stable stage and the speed of the vehicle reaches 10 km / h, the control module 5 determines whether to perform energy recovery or power supply by the hydrogen fuel cell power supply system 1 alone or jointly power supply by the hydrogen fuel cell power supply system 1 and the power battery system 4 according to the current speed V and the current torque T.

[0053] Specifically, in step 3, if the current speed V increases and the current torque T decreases, and the vehicle is going downhill, it means that power output is not needed at this time, and energy will be recovered. The recovery process first passes through the battery management system BMS to determine the SOC of the power battery system 4. Energy recovery is only performed when the charge is between 5% and 95% to ensure the service life of the power battery.

[0054] In step 3, if the current speed V decreases and the current torque T increases, the vehicle may be going uphill or braking. At this time, a braking judgment is required. The brake pedal travel Lb can be used to determine that the current working condition of the vehicle is the braking mode.

[0055] If braking, energy is recovered.

[0056] Otherwise, the output power required by the vehicle increases, and the hydrogen fuel cell power supply system 1 is controlled to increase the output.

[0057] When P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system 1 and the power battery system 4 need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system 1 needs to output power. 出 Indicates the output power required by the car, P H2max represents the maximum output power of the hydrogen fuel cell power supply system 1, P 动 represents the output power required by the power battery system 4, P H2 Represents the output power of the hydrogen fuel cell power supply system 1.

[0058] In step 3, if the accelerator pedal is used (which can be determined based on the accelerator pedal travel La), and the current speed V increases and the current torque T increases, the vehicle is accelerating; when P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system 1 and the power battery system 4 need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system 1 needs to output power.

[0059] If the accelerator pedal is used (which can be determined based on the accelerator pedal travel La), and the current speed V remains unchanged and the current torque T increases, the vehicle is going uphill; when P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system 1 and the power battery system 4 need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system 1 needs to output power.

[0060] Furthermore, the control module 5 optimizes the output power P required by the vehicle through the particle swarm algorithm based on the speed, torque and time information and takes low fuel consumption as the optimization goal. 出 And the output power P of the hydrogen fuel cell power supply system 1 H2 . This will reduce hydrogen fuel consumption and increase vehicle mileage.

[0061] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A hybrid power system for new energy vehicles, characterized in that: It includes a battery management system (BMS), a hydrogen fuel cell power supply system (1), a power monitoring device (2), a bidirectional DC rectifier (3), a power battery system (4), a control module (5), a power battery charger (6), a traction inverter (7), a traction motor (TM), an auxiliary inverter (8), a chopper module (9), and a brake resistor (10); The hydrogen fuel cell power supply system (1) is electrically connected to the power monitoring device (2), the bidirectional DC rectifier (3), and the control module (5) in sequence; the power battery system (4) is electrically connected to the control module (5); the control module (5) is electrically connected to the traction motor (TM) through the traction inverter (7); the control module (5) is electrically connected to the auxiliary load (11) through the auxiliary inverter (8); the traction inverter (7) and the auxiliary inverter (8) are both electrically connected to the braking resistor (10) through the chopper module (9); the traction inverter (7) and the auxiliary inverter (8) are both electrically connected to the power battery system (4) through the power battery charger (6); the battery management system (BMS) is electrically connected to the power monitoring device (2), the control module (5), and the power battery system (4); and the control module (5) is also electrically connected to the traction motor (TM); The working process of the hybrid power system includes the following steps: Step 1. The vehicle starts, at which time the vehicle speed V is 0 and the torque is T0, and the control module (5) controls the power battery system (4) to provide all the starting power; Step 2. As the vehicle is traveling, the control module (5) determines whether the output of the hydrogen fuel cell power supply system (1) is stable through the power monitoring device (2); if it is not stable, the vehicle will continue to travel for a set time and then make another determination; if it is stable, the control module (5) controls the hydrogen fuel cell power supply system (1) to gradually replace the power battery system (4) for output; Step 3. When the vehicle reaches a relatively stable stage, the control module (5) determines whether to perform energy recovery or the hydrogen fuel cell power supply system (1) to supply power alone or the hydrogen fuel cell power supply system (1) and the power battery system (4) to supply power together according to the current speed V and the current torque T.

2. A new energy vehicle hybrid power system according to claim 1, characterized in that: Determining whether the output of the hydrogen fuel cell power supply system (1) is stable by using the power monitoring device (2) is specifically as follows: after the hydrogen fuel cell power supply system (1) responds, recording the output power P at the xth second x , the power P at (x+1) seconds x+1 , using the formula (P x+1 -P x ) / P x Determine P x+1 Compared to P x If the rate of change is within the set range of change, the output of the hydrogen fuel cell power supply system (1) is stable; otherwise, the output of the hydrogen fuel cell power supply system (1) is unstable and waits for the next determination.

3. A new energy vehicle hybrid power system according to claim 2, characterized in that: The setting variation range is ±5%.

4. A new energy vehicle hybrid power system according to claim 1, characterized in that: The setting time is 3 to 5 minutes.

5. A new energy vehicle hybrid power system according to claim 1, characterized in that: In step 3, if the current speed V increases and the current torque T decreases, it means that power output is not needed at this time, and energy will be recovered. The recovery process first passes through the battery management system (BMS) to determine the SOC of the power battery system (4). Energy recovery is only performed when the charge is between 5% and 95%, so as to ensure the service life of the power battery.

6. A new energy vehicle hybrid power system according to claim 5, characterized in that: In step 3, if the current speed V decreases and the current torque T increases, a braking determination is performed; if braking is performed, energy is recovered; otherwise, the output power required by the vehicle increases, and the hydrogen fuel cell power supply system (1) is controlled to increase output; When P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system (1) and the power battery system (4) need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system (1) needs to output power; P 出 Indicates the output power required by the car, P H2max represents the maximum output power of the hydrogen fuel cell power supply system (1), P 动 represents the output power required to be provided by the power battery system (4), P H2 Represents the output power of the hydrogen fuel cell power supply system (1).

7. A new energy vehicle hybrid power system according to claim 6, characterized in that: In step 3, if the accelerator pedal is used, and the current speed V increases and the current torque T increases; when P 出 ≥P H2max , then P 出 =P H2max +P 动 , the hydrogen fuel cell power supply system (1) and the power battery system (4) need to jointly output power; otherwise P 出 =P H2 , only the hydrogen fuel cell power supply system (1) needs to output power.

8. The hybrid power system for new energy vehicles according to claim 1, characterized in that: The relatively stable stage is when the car speed reaches 10Km / h.

9. A new energy vehicle hybrid power system according to claim 1, characterized in that: The bidirectional DC rectifier (3) supports smart grid and V2G technology.

10. A new energy vehicle hybrid power system according to claim 1, characterized in that: The control module (5) optimizes the output power P required by the vehicle by using a particle swarm algorithm based on the speed, torque and time information and taking low fuel consumption as the optimization goal. 出 And the output power P of the hydrogen fuel cell power supply system (1) H2 .

Images