CN113086214B

CN113086214B - Configuration method of fuel cell hybrid power supply system for unmanned aerial vehicle

Info

Publication number: CN113086214B
Application number: CN202110295726.2A
Authority: CN
Inventors: 李凯; 杨桂; 王仁康; 殷聪; 曹继申; 高艳
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2022-06-03
Anticipated expiration: 2041-03-19
Also published as: CN113086214A

Abstract

The invention provides a configuration method of a fuel cell hybrid power supply system for an unmanned aerial vehicle, which comprises the following specific steps: firstly, selecting an unmanned aerial vehicle flight platform to obtain the maximum weight configuration of a power supply system; carrying out a flight test to obtain the flight power in the takeoff process and the average power requirement in the steady-state flight process so as to obtain the steady-state output power grade and the weight of the fuel cell; when the weight of the fuel cell is less than the maximum weight configuration, calculating to obtain the sum of the weight of the hydrogen and the weight of the auxiliary power supply; carrying out a fuel cell loading test to obtain the shortest loading time and output power of the fuel cell; calculating the minimum energy density requirement of the auxiliary power supply, selecting the auxiliary power supply when the minimum energy density requirement is smaller than the maximum energy density to obtain the weight ratio of the auxiliary power supply, and obtaining the weight ratio of hydrogen after weight constraint judgment, wherein the obtained weight ratio of the auxiliary power supply and the hydrogen weight ratio are the longest endurance time configuration of the unmanned aerial vehicle flight platform under the maximum takeoff weight.

Description

Configuration method of fuel cell hybrid power supply system for unmanned aerial vehicle

Technical Field

The invention belongs to the field of fuel cells, and particularly relates to a configuration method of a fuel cell hybrid power supply system for an unmanned aerial vehicle.

Background

With the development of the unmanned aerial vehicle industry, the unmanned aerial vehicle is widely applied to military and civil fields by virtue of the advantages of small size, easy operation, low cost and the like. Unmanned aerial vehicle generally adopts the lithium cell energy supply, has the shortcoming of showing that the time of endurance is short, greatly restricts unmanned aerial vehicle's development. For improving unmanned aerial vehicle continuation of the journey mileage, use the fuel cell hybrid power system that hydrogen energy and auxiliary power source constitute for the unmanned aerial vehicle energy supply, overturn unmanned aerial vehicle's application scene and use strategy, have high potential using value.

Because the inside nature of hydrogen fuel cell is chemical reaction, its output power receives the coupling restriction of a plurality of factors, can't satisfy the demand of unmanned aerial vehicle take-off in-process power rapid change, need select auxiliary power source and hydrogen fuel cell to constitute hybrid power supply system for unmanned aerial vehicle energy supply. Energy constraint and weight constraint need be considered in the selection to auxiliary power supply, and under the certain circumstances of electrical power generating system weight, the too light auxiliary power supply weight ratio can't satisfy unmanned aerial vehicle take off the in-process to auxiliary power supply's energy demand, and the weight configuration of hydrogen can be alleviateed to the too heavy auxiliary power supply ratio, will reduce unmanned aerial vehicle's time of endurance. Under satisfying unmanned aerial vehicle energy demand, carry out rational configuration to hydrogen weight and auxiliary power supply weight, can effectively prolong unmanned aerial vehicle duration.

The hydrogen fuel cell unmanned aerial vehicle has gradually aroused people's attention at present, and the fuel cell hybrid power supply scheme also reaches consensus, but to the hydrogen of fuel cell hybrid power supply for the unmanned aerial vehicle and auxiliary power supply weight ratio problem, rarely has someone to involve. Chinese patent 202010020776.5 proposes a hydrogen fuel cell for an unmanned aerial vehicle, but does not specifically explain how to apply the hydrogen fuel cell to the unmanned aerial vehicle, and chinese patent 201911085243.9 proposes a hydrogen fuel cell unmanned aerial vehicle system, but does not indicate how to match the weight of hydrogen gas and the weight of an auxiliary power supply.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a fuel cell hybrid power supply system configuration method for an unmanned aerial vehicle, which is used for reasonably configuring the weight of hydrogen and an auxiliary power supply according to the energy requirement and the output capacity of the fuel cell of the unmanned aerial vehicle and improving the endurance time of the unmanned aerial vehicle.

The specific technical scheme of the invention is as follows:

a method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle is characterized by comprising the following steps:

step 1: randomly selecting an unmanned aerial vehicle flight platform to obtain the body weight M of the unmanned aerial vehicle flight platform_{uav_rack}Carrying the weight M of the task equipment_devAnd maximum takeoff weight M_{uav_max}And calculating to obtain the maximum weight configuration M of the power supply system_power：

M_power＝M_{uav_max}-M_{uav_rack}-M_dev

Step 2: counter weight of unmanned aerial vehicle flight platform to maximum takeoff weight M_{uav_max}Performing flight test to obtain flight power P at each time during takeoff_uav,tAnd average power demand P during steady state flight_{uav_ave}；

And step 3: average power requirement P obtained according to step 2_{uav_ave}Determining the steady state output power level P of the fuel cell_{fc_ave}：

P_{fc_ave}＝(1+α)·P_{uav_ave}

Wherein alpha is a preset power loss coefficient under the condition that power loss is generated in the working process of the power supply system;

setting the output power of a single fuel cell stack to be P₁Weight of M₁According to the steady-state output power level P_{fc_ave}Determining the number of fuel cell stacks N required to obtain the required fuel cell weight M_fc；

And 4, step 4: if M is_fc＜M_powerThen the next step of configuration is carried out, and the sum M of the weight of the hydrogen and the weight of the auxiliary power supply is calculated_energy：

M_energy＝M_power-M_fc

Otherwise, the weight of the fuel cell system is larger than the maximum weight configuration of the power system, the next configuration of the auxiliary power weight and the hydrogen weight cannot be carried out, and the step 1 is returned to reselect the flight platform of the unmanned aerial vehicle;

and 5: carrying out a fuel cell loading test, loading the fuel cell from a zero power point to a steady state output power level P on the premise of ensuring the stability and the service life of the fuel cell_{fc_ave}Obtaining the shortest loading time T of the fuel cell according to the node voltage lowest limit value of the single fuel cell stack;

step 6: collecting the output voltage and the output current of the fuel cell at each moment in the shortest loading time T so as to obtain the output power P of the fuel cell at each moment_fc,t，t＝1,2,…,T；

And 7: the fuel cell is in the shortest loading time T after the unmanned aerial vehicle flight platform leaves the ground, partial energy is provided by the auxiliary power supply, and the capacity requirement E of the auxiliary power supply_batSatisfy the relation:

wherein, beta is the loss coefficient of the energy conversion process measured in the fuel cell loading test;

and 8: if the sum of the weight of the hydrogen and the weight of the auxiliary power supply is M_energyAll auxiliary power supplies are configured, and the minimum energy density requirement e of the auxiliary power supplies is calculated_{min_bat}：

e_{min_bat}＝E_bat/M_energy

And step 9: carrying out feasibility analysis on the auxiliary power supply configuration, and searching to obtain the highest energy density e in all auxiliary power supplies_{max_density}According to the minimum energy density requirement e_{min_bat}And (3) judging:

e_{min_bat}＜e_{max_density}

if yes, carrying out the next step; otherwise, the auxiliary power supply meeting the energy density requirement cannot be found, and the step 1 is returned to reselect the flight platform of the unmanned aerial vehicle;

step 10: selecting the energy density as e_densityAccording to the capacity requirement E of the auxiliary power supply_batObtaining the weight ratio M of the auxiliary power supply_bat：

M_bat＝(E_bat/e_density)·(1+γ)

Wherein gamma is a preset weight configuration excess coefficient of the auxiliary power supply;

step 11: considering the minimum weight limit of hydrogen counterweight in the actual configuration process, and adding M to the weight of hydrogen and the weight of the auxiliary power supply_energyAnd auxiliary power supply weight ratio M_batAnd (3) carrying out weight constraint judgment:

M_bat＜M_energy(1-δ)

wherein, delta is the lowest coefficient of hydrogen weight configuration;

if yes, carrying out the next step; otherwise, indicating that the energy density of the auxiliary power supply is unreasonable to select, returning to the step 10 to reselect the auxiliary power supply;

step 12: calculating to obtain the weight ratio of the hydrogen

Weight ratio M of the obtained auxiliary power supply_batIn proportion by weight of hydrogen

To maximum takeoff weight M_{uav_max}The following maximum endurance configuration.

Further, the specific process of obtaining the shortest loading time T in step 5 is as follows:

step 5.1: in order to avoid the situation that the service life of the fuel cell is reduced due to the fact that the electricity-saving voltage is too low because the loading speed is too high in the loading process, the electricity-saving voltage V of each electricity-saving stack in the loading process is required_iSatisfies the following conditions:

V_i≥V_limit，1≤i≤N

wherein, V_limitA minimum limit for the cell voltage of the fuel cell stack;

step 5.2: setting the initial loading time of the fuel cell during the loading process as T_oAnd when the step length of each loading time change is delta T, the loading time of the fuel cell in the nth loading test is T_n：

T_n＝T_n-1+ΔT，n≥1

Wherein, T_n-1Loading time of the fuel cell in the (n-1) th loading test;

step 5.3: recording the voltage V of each power-saving pile in each loading test_i,nI is more than or equal to 1 and less than or equal to N, N is more than or equal to 1, and when V appears in the loading test of the V time_i,v＜V_limitWhen i is more than or equal to 1 and less than or equal to N, the loading time T of the fuel cell in the v-1 th loading test is set_v-1Is the shortest load time T.

Further, the power loss coefficient alpha in the step 3 is in the range of 0.05-0.2.

Further, the fuel cell system weight M in step 3_fcIncluding the fuel cell stack weight, the fuel cell accessory weight, the DC _ DC control board weight, and the hydrogen cylinder weight.

Further, the initial loading speed T in step 5.2_oNot less than 60s, and the loading time change step length delta T is 1-5 s.

Furthermore, in the step 10, the weight configuration excess coefficient γ of the auxiliary power supply is in a range of 0.2-2.

Further, the minimum coefficient delta of the hydrogen weight configuration in the step 11 is in the range of 0.6-0.8.

The invention has the beneficial effects that:

the invention provides a fuel cell hybrid power supply system configuration method for an unmanned aerial vehicle.

Drawings

Fig. 1 is a flowchart of a method for configuring a hybrid power supply system for a fuel cell for an unmanned aerial vehicle according to embodiment 1 of the present invention;

fig. 2 is a flowchart of a fuel cell loading test in a method for configuring a hybrid power supply system for a fuel cell for an unmanned aerial vehicle according to embodiment 1 of the present invention;

fig. 3 is a power change curve diagram of a takeoff process of an unmanned aerial vehicle flight platform in the configuration method of the fuel cell hybrid power supply system for an unmanned aerial vehicle according to embodiment 1 of the present invention;

fig. 4 is a graph of power change and average power demand of a flight platform of an unmanned aerial vehicle in a steady-state flight process in the configuration method of the fuel cell hybrid power supply system for an unmanned aerial vehicle according to embodiment 1 of the present invention;

fig. 5 is a graph of a power loading change and a steady-state output power level of a fuel cell in a shortest loading time in the configuration method of the fuel cell hybrid power supply system for the unmanned aerial vehicle obtained in embodiment 1 of the present invention;

fig. 6 is a graph showing a power change of a flight platform of the unmanned aerial vehicle from takeoff to steady-state flight, a power loading change of the fuel cell, and an output power change of the auxiliary power supply in the configuration method of the fuel cell hybrid power supply system for the unmanned aerial vehicle according to embodiment 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the following embodiments and the accompanying drawings.

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

Example 1

The embodiment provides a method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle, as shown in fig. 1, including the following steps:

step 1: setting the randomly selected unmanned aerial vehicle flight platform as Dajiang S1000, and obtaining the body weight M of the unmanned aerial vehicle flight platform_{uav_rack}＝4.4kg、Carrying task equipment weight M_dev1kg and maximum takeoff weight M_{uav_max}Calculating to obtain the maximum weight configuration M of the power supply system as 12.4kg_power：

M_power＝M_{uav_max}-M_{uav_rack}-M_dev＝7kg

Step 2: counter weight of unmanned aerial vehicle flight platform to maximum takeoff weight M_{uav_max}Flight tests are carried out on the basis of 12.4kg, and the flight power P at each moment in the takeoff process (about 8-30 s as shown in FIG. 3) is obtained_uav,tAnd obtaining the flight power P at each moment in the steady-state flight process (about 30-40 s of time shown in figure 4)_uav,tTo obtain an average power demand P_{uav_ave}2.1kW, as shown in fig. 4;

and step 3: average power requirement P obtained according to step 2_{uav_ave}Determining the steady-state output power level P of the fuel cell as 2.1kW_{fc_ave}：

P_{fc_ave}＝(1+α)·P_{uav_ave}＝(1+0.15)·2.1kW＝2.415kW

setting the output power of a single fuel cell stack to be P₁38W, weight M₁60g, according to the steady state output power level P_{fc_ave}2.415kW, the stack number N of the required fuel cell is determined to 64, and the weight M of the fuel cell including the weight of the fuel cell stack, the weight of the fuel cell accessories, the weight of the DC _ DC control board and the weight of the hydrogen cylinder is obtained_fc＝5.5kg；

And 4, step 4: at this time M_fc＜M_powerThe next step is carried out, and the sum M of the weight of the hydrogen and the weight of the auxiliary power supply is calculated_energy：

M_energy＝M_power-M_fc＝1.5kg

And 5: a fuel cell loading test is carried out, the flow is shown in figure 2, and the fuel cell is loaded from a zero power point to a steady-state output power level P on the premise of ensuring the stability and the service life of the fuel cell_{fc_ave}Obtaining the shortest loading time T of the fuel cell according to the node voltage lowest limit value of the single fuel cell stack;

the method comprises the following specific steps:

step 5.1: in order to avoid the reduction of the service life of the fuel cell due to the over-low electricity-saving voltage caused by the over-high loading speed in the loading process, the electricity-saving voltage V of each electricity-saving stack in the loading process is required_iSatisfies the following conditions:

V_i≥V_limit，1≤i≤64

wherein, V_limitThe lowest limit value of the electricity-saving voltage of a single electricity-saving stack of the fuel cell is 0.5V;

step 5.2: setting the initial loading time T of the fuel cell during the loading process_o60s, the loading speed change step of each loading test is delta T4 s, and the fuel cell loading time T in the nth loading test is_nComprises the following steps:

T_n＝T_n-1+ΔT，n≥1

wherein, T_n-1Loading time of the fuel cell in the (n-1) th loading test;

step 5.3: recording the voltage V of each power-saving pile in each loading test_i,nI is more than or equal to 1 and less than or equal to N, N is more than or equal to 1, and when V appears in the loading test of the V time_i,v＜V_limitWhen i is more than or equal to 1 and less than or equal to N, the loading time T of the fuel cell in the v-1 th loading test is set_v-1Minimum load time T:

T＝20s

step 6: collecting the output voltage and the output current of the fuel cell at each moment within the shortest loading time T-20 s, and further obtaining the output power P of the fuel cell at each moment_fc,tT ═ 1,2, …, T, as shown in fig. 5;

and 7: the fuel cell is provided with partial energy by the auxiliary power supply within the shortest loading time T of the unmanned aerial vehicle flying platform from the ground being 20s, as shown in fig. 6, the output power P of the auxiliary power supply at each moment_bat,tT is 1,2, …, T is:

P_bat,t＝P_uav,t-P_fc,t(1-β)，t＝1,2,…,T

capacity requirement E of auxiliary power supply_batSatisfy the relation:

wherein, beta is the loss coefficient of the energy conversion process measured in the fuel cell loading test, and is 0.06;

further obtaining the capacity requirement E of the auxiliary power supply_bat＝20Wh；

And 8: if the sum of the weight of the hydrogen and the weight of the auxiliary power supply is M_energyAll auxiliary power supplies are configured as 1.5kg, and the minimum energy density requirement e of the auxiliary power supplies is calculated_{min_bat}：

e_{min_bat}＝E_bat/M_enrtgy＝13.3Wh/kg

And step 9: carrying out feasibility analysis on the auxiliary power supply configuration, and searching to obtain the highest energy density e in all auxiliary power supplies_{max_density}180Wh/kg, according to minimum energy density requirement e_{min_bat}And (3) judging:

e_{min_bat}＜e_{max_density}

if yes, carrying out the next step;

step 10: selecting the energy density as e_density120Wh/kg auxiliary power supply according to the capacity requirement E of the auxiliary power supply_batObtaining the weight ratio M of the auxiliary power supply_bat：

M_bat＝(E_bat/e_density)·(1+γ)＝(20/120)·(1+0.2)＝0.2kg

M_bat＜M_energy(1-δ)＝1.5(1-0.6)＝0.6kg

if yes, carrying out the next step;

wherein, delta is the lowest coefficient of hydrogen weight configuration;

step 12: calculating to obtain the weight ratio M of the hydrogen_H2：

M_H2＝M_energy-M_bat＝1.3kg

Weight ratio M of the obtained auxiliary power supply_bat0.2kg of hydrogen in a weight ratio M_H21.3kg is the maximum takeoff weight M_{uav_max}The following maximum endurance configuration.

Claims

1. A method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle is characterized by comprising the following steps:

step 1: randomly selecting the flight platform of the unmanned aerial vehicle to obtain the body weight M of the flight platform of the unmanned aerial vehicle_{uav_rack}Carrying the weight M of the task equipment_devAnd maximum takeoff weight M_{uav_max}And calculating to obtain the maximum weight configuration M of the power supply system_power：

M_power＝M_{uav_max}-M_{uav_rack}-M_dev

Step 2: counter weight of unmanned aerial vehicle flight platform to maximum takeoff weight M_{uav_max}Performing flight test to obtain flight power P at each time during takeoff_uav，tAnd average power demand P during steady state flight_{uav_ave}；

And step 3: determining a steady state output power level P of a fuel cell_{fc_ave}：

P_{fc_ave}＝(1+α)·P_{uav_ave}

Wherein alpha is a preset power loss coefficient;

setting the output power of a single fuel cell stack to be P₁Weight of M₁Further determining the required number of fuel cell stack nodes N and the fuel cell weight M_fc；

And 4, step 4: if M is_fc＜M_powerThen, the next step is carried out, and the sum M of the weight of the hydrogen and the weight of the auxiliary power supply is calculated_energy：

M_energy＝M_power-M_fc

Otherwise, returning to the step 1 to reselect the flight platform of the unmanned aerial vehicle;

and 5: carrying out a fuel cell loading test, loading the fuel cell from a zero power point to a steady state output power level P_{fc_ave}Calculating the shortest loading time T of the fuel cell according to the node voltage lowest limit value of the single fuel cell stack;

step 6: collecting the output voltage and the output current of the fuel cell at each moment in the shortest loading time T so as to obtain the output power P of the fuel cell at each moment_fc，t，t＝1，2，...，T；

∫₀ ^TP_uav，t·dt＝(∫₀ ^TP_fc，t·dt)·(1-β)+E_bat

and 8: calculating to obtain the minimum energy density requirement e of the auxiliary power supply_{min_bat}：

e_{min_bat}＝E_bat/M_energy

And step 9: finding the highest energy density e in all auxiliary power supplies_{max_density}And (4) judging:

e_{min_bat}＜e_{max_density}

if yes, carrying out the next step; otherwise, returning to the step 1 to reselect the flight platform of the unmanned aerial vehicle;

step 10: selecting the energy density as e_densityThe auxiliary power supply obtains the weight ratio M of the auxiliary power supply_bat：

M_bat＝(E_bat/e_density)·(1+γ)

step 11: for hydrogen weight and assistantSum of power supply weight M_energyAnd auxiliary power supply weight ratio M_batAnd (4) judging:

M_bat＜M_energy(1-δ)

wherein, delta is the lowest coefficient of hydrogen weight configuration;

if yes, carrying out the next step; otherwise, returning to step 10 to reselect the auxiliary power supply;

step 12: calculating to obtain the weight ratio of the hydrogen

2. The method for configuring the fuel cell hybrid power supply system for the unmanned aerial vehicle according to claim 1, wherein the specific process of obtaining the shortest loading time T in the step 5 is as follows:

step 5.1: require the voltage V of each power-saving pile in the loading process_iSatisfies the following conditions:

V_i≥V_limit，1≤i≤N

wherein, V_limitThe lowest limit value of the electricity-saving voltage of the single electricity-saving stack of the fuel cell is set;

step 5.2: setting the initial loading time of the fuel cell in the loading process as T_oAnd each loading time change step is delta T, the loading time of the fuel cell in the nth loading test is T_n：

T_n＝T_n-1+ΔT，n≥1

Wherein, T_n-1For the (n-1) th loadingFuel cell loading time in the test;

step 5.3: recording the voltage V of each power-saving pile in each loading test_i，nI is more than or equal to 1 and less than or equal to N, N is more than or equal to 1, and when V appears in the loading test of the V time_i，v＜V_limitWhen i is more than or equal to 1 and less than or equal to N, the loading time T of the fuel cell in the v-1 th loading test is set_v-1Is the shortest load time T.

3. The method according to claim 2, wherein the initial loading time T in step 5.2 is_oNot less than 60s, and the loading time change step length delta T is 1-5 s.

4. The method for configuring a hybrid power system for a fuel cell for an unmanned aerial vehicle according to any one of claims 1 to 2, wherein the power loss coefficient α in step 3 is in a range of 0.05 to 0.2.

5. The method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle as claimed in any one of claims 1 to 2, wherein the fuel cell system weight M in step 3_fcIncluding fuel cell stack weight, fuel cell accessory weight, DC _ DC control board weight, and hydrogen cylinder weight.

6. The method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle according to any one of claims 1 to 2, wherein the weight configuration excess factor γ of the auxiliary power supply in the step 10 is in a range of 0.2 to 2.

7. The method for configuring a fuel cell hybrid power supply system for an unmanned aerial vehicle according to any one of claims 1 to 2, wherein the minimum coefficient δ of the hydrogen gas weight configuration in step 11 is in a range of 0.6 to 0.8.