Island wind power hydrogen production system improved voltage-power control method considering high-sensitivity factor influence

Abstract

The invention discloses an island wind power hydrogen production system improved voltage-power control method considering the influence of a high-sensitivity factor, and the method comprises the steps: introducing the high-sensitivity factor average wind speed and the DC bus voltage which affect the hydrogen production efficiency, and taking the DC bus voltage as a control parameter; the relation between the average wind speed and the direct-current bus voltage variable quantity is obtained, the direct-current bus voltage actual compensation quantity is designed to obtain a direct-current bus voltage reference value traced by the direct-current bus voltage actual value, and the working mode of the hydrogen production device is dynamically adjusted according to the direct-current bus voltage actual value so that the hydrogen production device can operate in a proper power interval. According to the improved voltage-power control method, a strategy for dynamically adjusting the direct current bus voltage according to the average wind speed and a strategy for dynamically adjusting the hydrogen production device according to the actual value of the direct current bus voltage are provided, the relation between the average wind speed and the direct current bus voltage is quantified, and the reference power of the hydrogen production device is obtained; the method has good effectiveness and superiority in the aspects of hydrogen production efficiency, SOC and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind turbines participating in hydrogen production, and in particular to the technical field of control of hydrogen production devices in isolated wind power hydrogen production systems. Specifically, the present invention provides an improved voltage-power control method for isolated wind power hydrogen production systems taking into account the influence of highly sensitive factors. Background Art

[0002] Vigorously developing renewable energy sources such as wind and solar energy is an important way to promote the realization of the "dual carbon" goals. However, renewable energy sources such as wind and solar have inherent characteristics such as intermittency and randomness, which will cause strong volatility in the output of conventional wind and solar power generation, and also bring many adverse effects on the safe and reliable operation of power grid connection, and even cause more serious problems such as wind and solar abandonment. Wind power hydrogen production technology can absorb surplus energy to electrolyze hydrogen, which is an important means to solve the problem of wind abandonment and wind power consumption, and can realize "green hydrogen" and help achieve the "dual carbon" goals. Hydrogen production efficiency can reflect and affect the system's hydrogen production performance and system operation to a certain extent. Higher hydrogen production efficiency is conducive to ensuring the overall performance and reliability of the system. In practical applications, it is difficult for hydrogen production devices to obtain higher hydrogen production efficiency due to the influence of many factors. In addition, the hydrogen storage coordinated control strategy can ensure the stable operation of the system. Therefore, it is necessary to study the optimization control and operation strategy of hydrogen production devices under the influence of many factors.

[0003] According to existing research, although some control methods consider power distribution and coordinated operation, they do not consider the impact of wind speed or power fluctuations on the efficiency of hydrogen production systems; some studies consider influencing factors in the control strategy, but consider less about the impact on hydrogen production efficiency; and some studies only consider a single factor in the control strategy, which improves the hydrogen production performance of hydrogen production devices to a certain extent. However, these studies have not studied the highly sensitive factors that affect hydrogen production efficiency, and are relatively rough when considering control variables.

[0004] In summary, there are few studies that consider highly sensitive factors in the control of hydrogen production devices in wind power hydrogen production systems, and further research is still needed. Therefore, the present invention proposes an improved voltage-power control of an isolated wind power hydrogen production system that considers the influence of highly sensitive factors, so as to improve the performance of the hydrogen production device under highly sensitive factors. Summary of the invention

[0005] The purpose of the present invention is to provide an improved voltage-power control method for an isolated island wind power hydrogen production system taking into account the influence of highly sensitive factors, in order to address the problem that the hydrogen production device in the current wind power hydrogen production system cannot obtain a high hydrogen production efficiency under highly sensitive factors, resulting in poor hydrogen production performance.

[0006] The purpose of the present invention is to be solved by the following technical solutions:

[0007] The improved voltage-power control method for an isolated wind power hydrogen production system considering the influence of highly sensitive factors provided by the present invention adopts an isolated wind power hydrogen production system including a wind turbine, an energy storage device and a hydrogen production device. The improved voltage-power control method introduces the average wind speed and DC bus voltage, which are highly sensitive factors affecting the hydrogen production efficiency, and uses the DC bus voltage as a control parameter. By establishing an isolated wind power hydrogen production system model without an energy storage device, a relationship curve between the average wind speed and the DC bus voltage is obtained, and then the numerical relationship between the average wind speed v and the DC bus voltage change ΔU is obtained. The actual compensation amount of the DC bus voltage is designed to obtain a DC bus voltage reference value. Based on the DC bus voltage reference value, PID control is implemented in which the outer loop of the energy storage device is the DC bus voltage and the inner loop is the charge and discharge current of the energy storage device, so that the actual value of the DC bus voltage U bus Able to track and approach the DC bus voltage reference value U in real time bus_ref ; The actual value of the DC bus voltage U bus The minimum DC bus voltage U min , DC bus voltage rated value U ref , DC bus voltage maximum value U max , the maximum voltage U of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t max (t), U min (t) is the minimum voltage U of the energy storage device when charging the isolated island wind power hydrogen production system at time t min (t) Compare and determine the working mode of the hydrogen production device and the reference power P of the hydrogen production device el_ref , that is, the isolated wind power hydrogen production system adopts voltage-power control and according to the actual value of DC bus voltage U bus Dynamically adjust the working mode of the hydrogen production device to make the hydrogen production device operate in an appropriate power range.

[0008] An improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of highly sensitive factors is characterized in that the method steps are as follows:

[0009] A. Perform wind speed monitoring to obtain the average wind speed v within the set wind speed monitoring period;

[0010] B. Compare the average wind speed v in step A with the insulation critical wind speed v1. If v>v1, proceed to step C. If v≤v1, determine the DC bus voltage change ΔU>0 and proceed to step E.

[0011] C. Compare the average wind speed v in step A with the rated critical wind speed v2. If v≥v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D. If v<v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D.

[0012] D. Determine the DC bus voltage change ΔU and proceed to step E;

[0013] E. Determine the actual compensation amount ΔU' of the DC bus voltage and proceed to step F;

[0014] F. Obtain the DC bus voltage U' before compensation based on the droop control curve of the energy storage device bus_ref , determine the DC bus voltage reference value U bus_ref ;

[0015] G. According to the DC bus voltage reference value U bus_ref The outer loop of the energy storage device is the DC bus voltage, and the inner loop is the PID control of the energy storage device charging and discharging current, so that the actual value of the DC bus voltage U bus Able to track and approach the DC bus voltage reference value U in real time bus_ref ;

[0016] H. Set the actual value of DC bus voltage U bus and the minimum DC bus voltage U min , DC bus voltage rated value U ref , DC bus voltage maximum value U max For comparison, when U min ≤U bus <U ref If U ref <U bus ≤U max If U bus =U ref When the POSITION is reached, the process proceeds to step I or step J;

[0017] I. The actual value of the DC bus voltage U bus The minimum DC bus voltage U min , the maximum voltage U of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t max (t) is compared, when U min ≤U bus ≤U max (t), the energy storage device is determined to discharge according to the set droop control curve and the process goes to step K; otherwise, the hydrogen production device is determined to operate in the maximum hydrogen production efficiency range and the process goes to step K;

[0018] J. The actual value of the DC bus voltage U bus with U min (t) is the minimum voltage U of the energy storage device when charging the isolated island wind power hydrogen production system at time t min (t), maximum DC bus voltage U max For comparison, when U min (t)≤Ubus ≤U max When the energy storage device is charged according to the set droop control curve, the process goes to step K; otherwise, the hydrogen production device is determined to be operating in the maximum hydrogen production efficiency range and the process goes to step K;

[0019] K. Determine the reference power P of the hydrogen production device el_ref , and proceed to step L;

[0020] L, according to the reference power P of the hydrogen production device el_ref The outer loop of the hydrogen production device is the hydrogen production power, and the inner loop is the PID control of the alkaline electrolyzer working current, so that the hydrogen production power P el Able to track and approach the reference power P of the hydrogen production device in real time el_ref , thereby realizing improved voltage-power droop control of the hydrogen production device, and entering step M;

[0021] M. Monitor whether the wind speed changes according to the set cyclic control period. If so, return to step A, otherwise return to step H.

[0022] The mathematical model of wind turbines used in the improved voltage-power control method of the isolated wind power hydrogen production system is:

[0023]

[0024] In formula (1), P m is the output power of the fan, W; ρ is the air density; C p is the wind energy utilization coefficient; v is the wind speed; R is the radius of the wind rotor; θ is the pitch angle of the wind rotor blade; ω is the rotation speed of the gear structure; λ is the tip speed ratio of the wind rotor blade; λ1 is an intermediate variable, which can be calculated from λ; the values ​​of the polynomial coefficients are: c1=0.5176, c2=116, c3=0.4, c4=5, c5=21, c6=0.0068.

[0025] The mathematical model of the hydrogen production device used in the improved voltage-power control method of the isolated wind power hydrogen production system is:

[0026] Output voltage U of alkaline electrolyzer el The formula is:

[0027]

[0028] In formula (2), U el is the output voltage of a single alkaline electrolyzer; U rev is the reversible voltage of the alkaline electrolytic cell; r1, r2 are ohmic resistance parameters; T el is the working temperature of the alkaline electrolyzer; k el , is the empirical parameter of overpressure of alkaline electrolyzer; Sel is the electrode surface area of ​​the alkaline electrolytic cell; I el is the working current of the alkaline electrolyzer;

[0029] Reversible voltage U of alkaline electrolyzer rev for:

[0030] U rev =U ro -K rev (T el -298.15) (3)

[0031] In formula (3), U ro is the reversible voltage of the alkaline electrolyzer under standard conditions; K rev is the temperature empirical coefficient of the reversible voltage;

[0032] The voltage of a single alkaline electrolytic cell is small, so multiple alkaline electrolytic cells need to be connected in series. The total output voltage of the series connection is:

[0033] U elc =n c U el (4)

[0034] In formula (4), U elc is the total output voltage when multiple alkaline electrolytic cells are connected in series; n c is the number of alkaline electrolytic cells connected in series;

[0035] Hydrogen production efficiency η of alkaline electrolyzer el Depends on the current efficiency η of the alkaline electrolyzer I and the voltage efficiency η of the alkaline electrolyzer V , when the temperature and pressure are constant, the hydrogen production efficiency of the alkaline electrolyzer is el It can be expressed as:

[0036] η el =η I η V (5)

[0037] Voltage efficiency η of alkaline electrolyzer V The formula is as follows:

[0038] η V =U tn / U el ×100% (6)

[0039] In formula (6), U el is the output voltage of a single alkaline electrolyzer, V; U tn is the thermal neutral voltage, usually stable at 1.482V; the current efficiency η of the alkaline electrolyzer I The formula is as follows:

[0040]

[0041] In formula (7), I el is the working current of the alkaline electrolytic cell, A; S el is the electrode surface area of ​​the alkaline electrolytic cell, m 2 ; is an empirical parameter.

[0042] The insulation critical wind speed v1 in step B is the average wind speed v when the wind power generation power of the wind turbine set in the isolated island wind power hydrogen production system without energy storage device is the insulation power of the hydrogen production device; the rated critical wind speed v2 in step C is the average wind speed v when the wind power generation power of the wind turbine set in the isolated island wind power hydrogen production system without energy storage device is the rated power of the hydrogen production device.

[0043] The method for determining the DC bus voltage variation ΔU in step D is:

[0044] D1. Establish an isolated wind power hydrogen production system model without energy storage device, and obtain the DC bus voltage waveform when the average wind speed ranges from 5m / s to 12m / s;

[0045] D2. Based on the DC bus voltage waveform, the relationship curve between the average wind speed and the DC bus voltage is obtained. The numerical relationship between the average wind speed v and the DC bus voltage change ΔU is obtained by fitting the relationship curve:

[0046]

[0047] In formula (8), v1 is the insulation critical wind speed when the wind power generation power is the insulation power of the hydrogen production device; v2 is the rated critical wind speed when the wind power generation power is the rated power of the hydrogen production device; a1, b1, c1, a2, b2, c2 are expression coefficients, which can be obtained by curve fitting; ΔU is the change in DC bus voltage.

[0048] The method for determining the actual compensation amount ΔU' of the DC bus voltage in step E is as follows: the actual compensation amount ΔU' of the DC bus voltage is obtained by multiplying the DC bus voltage change ΔU by the compensation coefficient.

[0049]

[0050] In formula (9), k1 and k2 are compensation coefficients, and their value range is [-0.6, 0].

[0051] The DC bus voltage reference value U in step F bus_ref The method to determine is:

[0052] F1. Obtain the charge and discharge current I of the energy storage device based on the droop control curve of the energy storage device b and DC bus voltage U' before compensation bus_ref The relationship between them is:

[0053]

[0054] In formula (11) and (12), I is defined as b >0 means discharge, I b <0 is charging; m is the droop coefficient of the energy storage device charging and discharging based on voltage-current droop control; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; I bmax is the maximum discharge current of the energy storage device, I bmin is the minimum charging current of the energy storage device; U min (t) is the minimum voltage value of the energy storage device of the isolated island wind power hydrogen production system when charging at time t, U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t, U max (t), U min The (t) value is determined according to the SOC value of the energy storage device and is set as follows:

[0055]

[0056] In formula (10), U ref is the rated value of the DC bus voltage; ΔU S is the voltage dead zone; SOC max The maximum state of charge of the energy storage device, SOC min SOC is the minimum state of charge of the energy storage device; i is the SOC value of the energy storage device at the current moment;

[0057] F2, DC bus voltage reference value U bus_ref To compensate the DC bus voltage U' bus_ref The sum of the actual compensation value ΔU' of the DC bus voltage, that is, U bus_ref =U b ' us_ref +ΔU'.

[0058] The actual value U of the DC bus voltage in step H, step I, and step J bus The output power of the hydrogen production device satisfies the following relationship:

[0059]

[0060] In formula (13) and (14), P elNis the maximum power of the hydrogen production device, i.e. the rated power; P(t) is the output power of the hydrogen production device at time t; U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t, U min (t) is the minimum voltage value of the energy storage device of the isolated wind power hydrogen production system when charging at time t; l(t) is the discharge droop coefficient of the energy storage device at time t based on voltage-power droop control, and q(t) is the charging droop coefficient of the energy storage device at time t based on voltage-power droop control.

[0061] The reference power P of the hydrogen production device in step K el_ref The method for determining is: the reference power P of the hydrogen production device when the hydrogen production device in step H is operated at the insulation power el_ref The insulation power P of the hydrogen production device elmin The reference power P of the hydrogen production device when the hydrogen production device in step H is operated at rated power el_ref is the rated power P of the hydrogen production device elN The reference power P of the hydrogen production device in step I and step J is when the hydrogen production device operates in the maximum hydrogen production efficiency range. el_ref is the hydrogen production power P corresponding to the maximum hydrogen production efficiency range of the hydrogen production device elmax .

[0062] The reference power P of the hydrogen production device in step K el_ref The method to determine is:

[0063] In step I, when U min ≤U bus ≤U max (t), the reference power P of the hydrogen production device el_ref and the actual value of the DC bus voltage U bus The relationship is expressed as:

[0064]

[0065] In step J, when U min (t)≤U bus ≤U max When the reference power of hydrogen production device is P el_ref and the actual value of the DC bus voltage U bus The relationship is expressed as:

[0066]

[0067] In formula (15) and (16), P el_ref is the reference power of the hydrogen production device; P elmax is the hydrogen production power corresponding to the maximum hydrogen production efficiency range of the hydrogen production device; P elNis the rated power of the hydrogen production device; h1 is U min ≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system at time (t); U min (t) is the minimum voltage value of the energy storage device of the isolated island wind power hydrogen production system when charging at time t, U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; P elmin is the insulation power of the hydrogen production device; h2 is U min (t)≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system.

[0068] In the improved voltage-power control method for an isolated wind power hydrogen production system considering the influence of high sensitivity factors provided by the present invention, the wind speed sampling time interval is any value between 0.2s and 1s, the wind speed monitoring period in step A is any value between 1s and 2s, and the average wind speed is the average value of the sampled wind speeds within the wind speed monitoring period; the cycle control period in step M is any value between 3s and 10s. When setting the above wind speed sampling time interval, wind speed monitoring period, and cycle control period, it is necessary to pay attention to matching, such as the wind speed monitoring period is 1s and the cycle control period is 5s.

[0069] Compared with the prior art, the present invention has the following advantages:

[0070] The improved voltage-power control method for the isolated island wind power hydrogen production system of the present invention introduces the average wind speed and DC bus voltage, which are highly sensitive factors affecting the hydrogen production efficiency, and uses the DC bus voltage as a control parameter to obtain the relationship between the average wind speed and the change in the DC bus voltage. The actual compensation amount of the DC bus voltage is designed to obtain a DC bus voltage reference value that allows the actual value of the DC bus voltage to track, and the working mode of the hydrogen production device is dynamically adjusted according to the actual value of the DC bus voltage to make it operate in an appropriate power range; a strategy for dynamically adjusting the DC bus voltage according to the average wind speed and a strategy for dynamically adjusting the hydrogen production device according to the actual value of the DC bus voltage are proposed, the relationship between the average wind speed and the DC bus voltage is quantified, and the reference power of the hydrogen production device is obtained accordingly, which has good effectiveness and superiority in terms of hydrogen production efficiency and SOC. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Attached Figure 1 The topological structure of the isolated island wind power hydrogen production system provided by the present invention;

[0072] Attached Figure 2 A control block diagram of an improved voltage-power control method for an isolated island wind power hydrogen production system taking into account the influence of high sensitivity factors provided by the present invention;

[0073] Attached Figure 3 A flow chart of an improved voltage-power control method for an isolated island wind power hydrogen production system taking into account the influence of high sensitivity factors provided by the present invention;

[0074] Attached Figure 4 The present invention provided in the embodiment provides the relationship between the DC bus voltage and the average wind speed in the energy storage system without energy storage;

[0075] Attached Figure 5 A curve of the difference between wind power generation power and hydrogen production power obtained in a system without energy storage provided by the present invention in an embodiment;

[0076] Attached Figure 6 Energy storage device 1 of the present invention provided in the embodiment b -U bus droop control curve;

[0077] Attached Figure 7 A turbulent wind speed diagram in the range of 5 m / s to 6.2 m / s used in the experimental analysis provided in the embodiment;

[0078] Attached Figure 8 The SOC values ​​corresponding to different k1 values ​​at turbulent wind speeds in the range of 5m / s to 6.2m / s provided by the improved strategy of the present invention in the embodiment;

[0079] Attached Fig. 9 A turbulent wind speed diagram in the range of 8.1 m / s to 12 m / s used in the experimental analysis provided in the embodiment;

[0080] Attached Fig.10 The SOC values ​​corresponding to different k2 values ​​at turbulent wind speeds in the range of 8.1 m / s to 12 m / s for the improved strategy of the present invention provided in the embodiment;

[0081] Attached Fig.11 A simulation comparison diagram of the improved strategy of the present invention and the traditional strategy at step wind speed provided in the embodiment;

[0082] Attached Fig.12 A simulation comparison diagram of the improved strategy of the present invention and the traditional strategy at turbulent wind speeds provided in the embodiment. DETAILED DESCRIPTION

[0083] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0084] like Figure 1-3As shown, the improved voltage-power control method for an isolated wind power hydrogen production system considering the influence of highly sensitive factors provided by the present invention adopts an isolated wind power hydrogen production system including a wind turbine, an energy storage device and a hydrogen production device. The improved voltage-power control method introduces the average wind speed and DC bus voltage, which are highly sensitive factors affecting the hydrogen production efficiency, and uses the DC bus voltage as a control parameter. By establishing an isolated wind power hydrogen production system model without an energy storage device, a relationship curve between the average wind speed and the DC bus voltage is obtained, and then the numerical relationship between the average wind speed v and the DC bus voltage change ΔU is obtained. The actual compensation amount of the DC bus voltage is designed to obtain a DC bus voltage reference value. Based on the DC bus voltage reference value, PID control is implemented in which the outer loop of the energy storage device is the DC bus voltage and the inner loop is the charge and discharge current of the energy storage device, so that the actual value of the DC bus voltage U bus Able to track and approach the DC bus voltage reference value U in real time bus_ref ; The actual value of DC bus voltage U bus The minimum DC bus voltage U min , DC bus voltage rated value U ref , DC bus voltage maximum value U max , the maximum voltage U of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t max (t), U min (t) is the minimum voltage U of the energy storage device when charging the isolated island wind power hydrogen production system at time t min (t) Compare and determine the working mode of the hydrogen production device and the reference power P of the hydrogen production device el_ref , that is, the isolated wind power hydrogen production system adopts voltage-power control and according to the actual value of DC bus voltage U bus Dynamically adjust the working mode of the hydrogen production device to make the hydrogen production device operate in an appropriate power range.

[0085] The mathematical model of the wind turbine group used in the improved voltage-power control method of the isolated island wind power hydrogen production system considering the influence of high sensitivity factors provided by the present invention is:

[0086]

[0087] In formula (1), P m is the output power of the fan, W; ρ is the air density; C p is the wind energy utilization coefficient; v is the wind speed; R is the radius of the wind rotor; θ is the pitch angle of the wind rotor blade; ω is the rotation speed of the gear structure; λ is the tip speed ratio of the wind rotor blade; λ1 is an intermediate variable, which can be calculated from λ; the values ​​of the polynomial coefficients are: c1=0.5176, c2=116, c3=0.4, c4=5, c5=21, c6=0.0068.

[0088] The mathematical model of the hydrogen production device adopted by the improved voltage-power control method of the isolated island wind power hydrogen production system considering the influence of high sensitivity factors provided by the present invention is:

[0089] The formula for the output voltage Uel of the alkaline electrolyzer is:

[0090]

[0091] In formula (2), Uel is the output voltage of a single alkaline electrolytic cell; Urev is the reversible voltage of the alkaline electrolytic cell; r1, r2 are ohmic resistance parameters; Tel is the operating temperature of the alkaline electrolytic cell; kel, is the empirical parameter of overvoltage of alkaline electrolytic cell; Sel is the electrode surface area of ​​alkaline electrolytic cell; Iel is the working current of alkaline electrolytic cell;

[0092] The reversible voltage Urev of the alkaline electrolyzer is:

[0093] Urev=Uro-Krev(Tel-298.15)(3)

[0094] In formula (3), Uro is the reversible voltage of the alkaline electrolytic cell under standard conditions; Krev is the temperature empirical coefficient of the reversible voltage;

[0095] The voltage of a single alkaline electrolytic cell is small, so multiple alkaline electrolytic cells need to be connected in series. The total output voltage of the series connection is:

[0096] Uelc=ncUel(4)

[0097] In formula (4), Uelc is the total output voltage when multiple alkaline electrolytic cells are connected in series; nc is the number of alkaline electrolytic cells connected in series;

[0098] The hydrogen production efficiency ηel of the alkaline electrolyzer depends on the current efficiency η of the alkaline electrolyzer I and the voltage efficiency η of the alkaline electrolyzer V , when the temperature and pressure are constant, the hydrogen production efficiency ηel of the alkaline electrolyzer can be expressed as:

[0099] ηel=η I η V (5)

[0100] Voltage efficiency η of alkaline electrolyzer V The formula is as follows:

[0101] η V =Utn / Uel×100%(6)

[0102] In formula (6), Uel is the output voltage of a single alkaline electrolytic cell, V; Utn is the thermal neutral voltage, which is usually stable at 1.482 V;

[0103] Current efficiency η of alkaline electrolyzer I The formula is as follows:

[0104]

[0105] In formula (7), Iel is the working current of the alkaline electrolytic cell, A; Sel is the electrode surface area of ​​the alkaline electrolytic cell, m 2 ; is an empirical parameter.

[0106] like Figure 3 The flowchart of the improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors provided by the present invention is shown. The steps of the improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors are as follows:

[0107] A. Perform wind speed monitoring to obtain the average wind speed v within the set wind speed monitoring period;

[0108] B. Compare the average wind speed v in step A with the insulation critical wind speed v1. If v>v1, proceed to step C. If v≤v1, determine the DC bus voltage change ΔU>0 and proceed to step E.

[0109] C. Compare the average wind speed v in step A with the rated critical wind speed v2. If v≥v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D. If v<v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D.

[0110] D. Determine the DC bus voltage change ΔU and proceed to step E;

[0111] E. Determine the actual compensation amount ΔU' of the DC bus voltage and proceed to step F;

[0112] F. Obtain the DC bus voltage U' before compensation based on the droop control curve of the energy storage device bus_ref , determine the DC bus voltage reference value U bus_ref ;

[0113] G. According to the DC bus voltage reference value U bus_ref The outer loop of the energy storage device is the DC bus voltage, and the inner loop is the PID control of the energy storage device charging and discharging current, so that the actual value of the DC bus voltage U bus Able to track and approach the DC bus voltage reference value U in real time bus_ref ;

[0114] H. Set the actual value of DC bus voltage U bus The minimum DC bus voltage U min , DC bus voltage rated value U ref, DC bus voltage maximum value U max For comparison, when U min ≤U bus <U ref If U ref <U bus ≤U max If U bus =U ref When the POSITION is reached, the process proceeds to step I or step J;

[0115] I. The actual value of the DC bus voltage U bus The minimum DC bus voltage U min , the maximum voltage U of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t max (t) is compared, when U min ≤U bus ≤U max (t), the energy storage device is determined to discharge according to the set droop control curve and the process goes to step K; otherwise, the hydrogen production device is determined to operate in the maximum hydrogen production efficiency range and the process goes to step K;

[0116] J. The actual value of the DC bus voltage U bus with U min (t) is the minimum voltage U of the energy storage device when charging the isolated island wind power hydrogen production system at time t min (t), maximum DC bus voltage U max For comparison, when U min (t)≤U bus ≤U max When the energy storage device is charged according to the set droop control curve, the process goes to step K; otherwise, the hydrogen production device is determined to be operating in the maximum hydrogen production efficiency range and the process goes to step K;

[0117] K. Determine the reference power P of the hydrogen production device el_ref , and proceed to step L;

[0118] L, according to the reference power P of the hydrogen production device el_ref The outer loop of the hydrogen production device is the hydrogen production power, and the inner loop is the PID control of the alkaline electrolyzer working current, so that the hydrogen production power P el Able to track and approach the reference power P of the hydrogen production device in real time el_ref , thereby realizing improved voltage-power droop control of the hydrogen production device, and entering step M;

[0119] M. Monitor whether the wind speed changes according to the set cyclic control period. If so, return to step A, otherwise return to step H.

[0120] In the above method, many parameters need to be provided and defined, which will be explained in detail below.

[0121] Establish a system without energy storage (i.e., an isolated wind power hydrogen production system without energy storage device). In the system without energy storage, the wind turbine directly provides energy for the hydrogen production device. When the wind power generation power is less than the insulation power of the hydrogen production device, the DC bus voltage drops; when the wind power generation power reaches a balance with the power consumption of the hydrogen production device, the DC bus voltage remains stable; when the wind power generation power is greater than the rated power of the hydrogen production device, the hydrogen production device cannot fully absorb it, and the DC bus voltage rises. Therefore, a curve of the difference between wind power generation power and hydrogen production power can be obtained in the system without energy storage. According to the curve of the difference between wind power generation power and hydrogen production power, it is determined that the average wind speed v when the wind power generation power of the wind turbine is the insulation power of the hydrogen production device is the insulation critical wind speed v1, and the average wind speed v when the wind power generation power of the wind turbine is the rated power of the hydrogen production device is the rated critical wind speed v2.

[0122] A model of a system without energy storage is constructed to obtain the DC bus voltage waveform when the average wind speed ranges from 5m / s to 12m / s. The relationship curve between the average wind speed and the DC bus voltage is obtained based on the DC bus voltage waveform. The numerical relationship between the average wind speed v and the DC bus voltage change ΔU is obtained by fitting the relationship curve:

[0123]

[0124] In formula (8), v1 is the insulation critical wind speed when the wind power generation power is the insulation power of the hydrogen production device; v2 is the rated critical wind speed when the wind power generation power is the rated power of the hydrogen production device; a1, b1, c1, a2, b2, c2 are expression coefficients, which can be obtained by curve fitting; ΔU is the change in DC bus voltage;

[0125] The expression of the actual compensation amount ΔU' of the DC bus voltage obtained by multiplying the DC bus voltage change ΔU by the compensation coefficient is:

[0126]

[0127] In formula (9), k1 and k2 are compensation coefficients, which can be compared by taking different values, with a value range of [-0.6, 0], and set to the value when the hydrogen production effect is best.

[0128] In determining the DC bus voltage reference value U in step F bus_ref Before that, it is necessary to determine the five critical values ​​of the DC bus voltage, which are the DC bus voltage rated value U ref , DC bus voltage maximum value U max , DC bus voltage minimum value U min , Umax (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t, U min (t) is the minimum voltage value when the energy storage device of the isolated island wind power hydrogen production system is charged at time t; In the following embodiments of the present invention, the DC bus voltage rated value U ref Set to 800V. Since the maximum allowable deviation of the DC bus voltage is 5%, U max and U min Take 840V and 760V respectively; determine U according to the SOC value of the energy storage device max (t), U min (t) value, set as follows:

[0129]

[0130] In formula (10), ΔU S is the voltage dead zone; SOC max The maximum state of charge of the energy storage device, SOC min SOC is the minimum state of charge of the energy storage device; i is the SOC value of the energy storage device at the current moment; the present invention takes ΔU S =0.0125U ref =10V, the maximum SOC and minimum SOC of the energy storage unit are defined as 90% and 20% respectively; Substituting into formula (10), we can get: U max (t), U min The reference intervals of (t) are [790, 800] and [800, 810] respectively. max (t) is 790V, U min (t) is 810V.

[0131] After determining the critical value of the DC bus voltage, the DC bus voltage reference value U bus_ref The method to determine is:

[0132] F1. Obtain the charge and discharge current I of the energy storage device based on the droop control curve of the energy storage device b and DC bus voltage U' before compensation bus_ref The relationship between them is:

[0133]

[0134] In formula (11) and (12), I is defined as b >0 means discharge, I b <0 is charging; m is the droop coefficient of the energy storage device charging and discharging based on voltage-current droop control; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; Ibmax is the maximum discharge current of the energy storage device, I bmin It is the minimum value of charging current of the energy storage device;

[0135] F2, DC bus voltage reference value U bus_ref To compensate the DC bus voltage U' bus_ref The sum of the actual compensation value ΔU' of the DC bus voltage, that is, U bus_ref =U b ' us_ref +ΔU'.

[0136] The actual value U of the DC bus voltage in step H, step I, and step J bus The output power of the hydrogen production device satisfies the following relationship:

[0137]

[0138] In formula (13) and (14), P elN is the maximum power of the hydrogen production device, i.e. the rated power; P(t) is the output power of the hydrogen production device at time t; U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t, U min (t) is the minimum voltage value of the energy storage device of the isolated wind power hydrogen production system when charging at time t; l(t) is the discharge droop coefficient of the energy storage device at time t based on voltage-power droop control, and q(t) is the charging droop coefficient of the energy storage device at time t based on voltage-power droop control.

[0139] The reference power P of the hydrogen production device in step K el_ref The method for determining is: the reference power P of the hydrogen production device when the hydrogen production device in step H is operated at the insulation power el_ref The insulation power P of the hydrogen production device elmin The reference power P of the hydrogen production device when the hydrogen production device in step H is operated at rated power el_ref is the rated power P of the hydrogen production device elN The reference power P of the hydrogen production device in step I and step J is when the hydrogen production device operates in the maximum hydrogen production efficiency range. el_ref is the hydrogen production power P corresponding to the maximum hydrogen production efficiency range of the hydrogen production device elmax .

[0140] The reference power P of the hydrogen production device in step K el_ref The method to determine is:

[0141] In step I, when U min ≤U bus ≤U max (t), the reference power P of the hydrogen production device el_refand the actual value of the DC bus voltage U bus The relationship is expressed as:

[0142]

[0143] In step J, when U min (t)≤U bus ≤U max When the reference power of hydrogen production device is P el_ref and the actual value of the DC bus voltage U bus The relationship is expressed as:

[0144]

[0145] In formula (15) and (16), P el_ref is the reference power of the hydrogen production device; P elmax is the hydrogen production power corresponding to the maximum hydrogen production efficiency range of the hydrogen production device; P elN is the rated power of the hydrogen production device; h1 is U min ≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system at time (t); U min (t) is the minimum voltage value of the energy storage device of the isolated island wind power hydrogen production system when charging at time t, U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; P elmin is the insulation power of the hydrogen production device; h2 is U min (t)≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system.

[0146] According to an improved voltage-power control method for an isolated wind power hydrogen production system considering the influence of high sensitivity factors provided by the present invention, the hydrogen production device provided by the present invention has five working modes, based on the actual value of the DC bus voltage U bus The details of dynamically adjusting the working mode of the hydrogen production device are as follows.

[0147] Working mode 1:

[0148] U max (t)<U bus <U min (t), actual value of DC bus voltage U bus Within the allowable fluctuation range, the hydrogen production device operates in the maximum efficiency range, that is, P el_ref =Pelmax ;

[0149] Working mode 2:

[0150] U min (t)≤U bus ≤U max , the energy storage device is charged according to the droop control curve set by formulas (11) and (12). When the hydrogen production device senses that the DC bus voltage rises, it will increase the power consumption; at this time, the reference power P of the hydrogen production device el_ref and the actual value of the DC bus voltage U bus The relationship between is expressed in formula (15). Based on formula (15), the reference power P of the hydrogen device is obtained: el_ref ;

[0151] Working mode three:

[0152] U min ≤U bus ≤U max (t), the energy storage device is charged according to the droop control curve set by formulas (11) and (12). When the hydrogen production device senses that the DC bus voltage rises, it will increase the power consumption; at this time, the reference power P of the hydrogen production device el_ref and the actual value of the DC bus voltage U bus The relationship between is expressed in formula (16). Based on formula (16), the reference power P of the hydrogen device is obtained: el_ref ;

[0153] Working mode 4:

[0154] U bus >U max , the wind power generation power is greater than the sum of the power required for hydrogen production and the upper limit power of the energy storage unit, and the hydrogen production device operates at the rated power, that is, P el_ref =P elN ;

[0155] Working mode five:

[0156] U bus <U min , the sum of the wind power generation power and the upper limit power of the energy storage unit discharge is less than the power required for hydrogen production, and the hydrogen production device operates at the insulation power, that is, P el_ref =P elmin .

[0157] Example

[0158] A specific embodiment is provided below to further illustrate the control effect of an improved voltage-power control method for an isolated island wind power hydrogen production system taking into account the influence of high sensitivity factors provided by the present invention.

[0159] 1. Simulation Analysis

[0160] The isolated island wind power hydrogen production system required by the present invention includes a wind turbine, an energy storage device and a hydrogen production device such as Figure 1 , Figure 2 As shown. The DC bus voltage compensation is designed in a system without energy storage, and the control effect of an improved voltage-power control method for an isolated wind power hydrogen production system (hereinafter referred to as the improved strategy of the present invention) provided by the present invention considering the influence of high sensitivity factors when the working condition is switched is demonstrated. In order to verify the superiority and effectiveness of the improved strategy of the present invention, the improved strategy provided by the present invention and the voltage-power control used in a certain document (hereinafter referred to as the document strategy) are compared and analyzed using a step wind speed and a turbulent wind speed, respectively.

[0161] (a) The simulation parameters are shown in Table 1.

[0162] Table 1 Simulation parameters

[0163]

[0164]

[0165] (II) Analysis of simulation results

[0166] Figures 4 to 10 They are respectively the relationship between the DC bus voltage and the average wind speed without an energy storage system, the difference between the wind turbine power and the hydrogen production power without an energy storage system, the turbulent wind speed in the range of 5 to 6.2 m / s and the SOC values ​​corresponding to different k1 values, the turbulent wind speed in the range of 8.1 to 12 m / s and the SOC values ​​corresponding to different k2 values, and the simulation comparison diagram of different strategies under step wind speed and turbulent wind speed.

[0167] Depend on Figure 4 It can be seen that the piecewise function of the DC bus voltage compensation with respect to the average wind speed is as follows:

[0168]

[0169] Multiplying by the compensation coefficient, the expression of ΔU' is as follows:

[0170]

[0171] In formula (2), v is the average wind speed; k1 and k2 are compensation coefficients; ΔU is based on Figure 3 The DC bus voltage compensation amount obtained by curve fitting, ΔU', is the DC bus voltage compensation amount obtained by multiplying ΔU by the compensation coefficient.

[0172] Depend on Figure 5 , Figure 6It can be seen that when 5≤v≤6.2, k1=0,-0.1,-0.2,-0.3,-0.4,-0.5,-0.6 are taken respectively, and the hydrogen production efficiency and SOC value under each coefficient are compared. The hydrogen production efficiency and SOC value corresponding to different k1 values ​​are shown in Table 2, and the following analysis is made: When the k1 value changes from 0 to -0.5, the hydrogen production efficiency gradually increases, and the energy storage device discharges more and more. When k1=-0.6, the hydrogen production efficiency no longer increases, and the SOC value decreases slightly. Comprehensive analysis shows that when 5≤v≤6.2m / s, the k1 value of the present invention is -0.5.

[0173] Table 2 Hydrogen production efficiency and SOC values ​​corresponding to different k1 values

[0174]

[0175]

[0176] Depend on Figure 7 , Figure 8 It can be seen that when 8.1≤v≤12, k2=0,-0.1,-0.2,-0.3,-0.4,-0.5,-0.6 are taken respectively, and the hydrogen production efficiency and SOC value under each coefficient are compared. The hydrogen production efficiency and SOC value corresponding to different k2 values ​​are shown in Table 3, and the following analysis is made: When the k2 value changes from 0 to -0.5, the hydrogen production efficiency gradually increases, and the energy storage device is charged more and more. When k2=-0.6, the hydrogen production efficiency decreases, and the SOC value rises slightly and remains almost unchanged. Comprehensive analysis shows that when 8.1≤v≤12m / s, the k2 value of the present invention is -0.5.

[0177] Table 3 Hydrogen production efficiency and SOC values ​​corresponding to different k2 values

[0178]

[0179] When taking Fig.11 (a) shows the step wind speed. Compared with the literature strategy, the U of the improved strategy of the present invention is bus The amplitude of the step change with wind speed is small, such as Fig.11 (b) shows that, in addition, the energy storage device has a faster charging speed, a larger SOC value, and a higher hydrogen production efficiency, as shown in Fig.11 Table 4 shows the hydrogen production efficiency and SOC value of the two control strategies under step wind speed and the improvement of the improved strategy of the present invention compared with the strategy in the literature.

[0180] Table 4 Comparison results of different strategies under step wind speed

[0181]

[0182]

[0183] When taking Fig.12 (a) The U of the literature strategy is shown in the turbulent wind speed. bus Most are higher than 820V, and the U of the improved strategy of the present invention bus Mostly lower than 820V, such as Fig.12 (b) As shown. The SOC values ​​of the reference strategy and the improved strategy of the present invention are 50.7% and 50.81% respectively, and the hydrogen production efficiency is 82.19% and 82.43% respectively. Fig.12 (c) and 12 (d). Obviously, under the same turbulent wind speed, the hydrogen production efficiency and SOC value obtained by the improved strategy method are significantly greater than the hydrogen production efficiency and SOC value obtained by the literature strategy. Table 5 shows the hydrogen production efficiency and SOC value of the two control strategies under turbulent wind speed and the improvement of the improved strategy of the present invention relative to the literature strategy.

[0184] Table 5 Comparison results of different strategies under turbulent wind speed

[0185]

[0186] From the above analysis, it can be seen that the improved strategy of the present invention can better provide energy storage power and hydrogen production effect. Compared with the traditional control of voltage-power, the strategy proposed in the present invention has more advantages in hydrogen production efficiency and SOC.

[0187] The improved voltage-power control method for the isolated island wind power hydrogen production system of the present invention introduces the average wind speed and DC bus voltage, which are highly sensitive factors affecting the hydrogen production efficiency, and uses the DC bus voltage as a control parameter to obtain the relationship between the average wind speed and the change in the DC bus voltage. The actual compensation amount of the DC bus voltage is designed to obtain a DC bus voltage reference value that allows the actual value of the DC bus voltage to track, and the working mode of the hydrogen production device is dynamically adjusted according to the actual value of the DC bus voltage to make it operate in an appropriate power range; a strategy for dynamically adjusting the DC bus voltage according to the average wind speed and a strategy for dynamically adjusting the hydrogen production device according to the actual value of the DC bus voltage are proposed, the relationship between the average wind speed and the DC bus voltage is quantified, and the reference power of the hydrogen production device is obtained accordingly, which has good effectiveness and superiority in terms of hydrogen production efficiency and SOC.

[0188] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. Technologies not covered by the present invention can be implemented by existing technologies.

Claims

1. An improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors, characterized in that: The steps of this method are as follows: A. Perform wind speed monitoring to obtain the average wind speed v within the set wind speed monitoring period; B. Compare the average wind speed v in step A with the insulation critical wind speed v1. If v>v1, proceed to step C. If v≤v1, determine the DC bus voltage change ΔU>0 and proceed to step E. C. Compare the average wind speed v in step A with the rated critical wind speed v2. If v≥v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D. If v<v2, determine that the DC bus voltage change ΔU is less than 0 and proceed to step D. D. Determine the DC bus voltage change ΔU and proceed to step E; E. Determine the actual compensation amount ΔU' of the DC bus voltage and proceed to step F; F. Obtain the DC bus voltage U' before compensation based on the droop control curve of the energy storage device bus_ref , determine the DC bus voltage reference value U bus_ref ; G. According to the DC bus voltage reference value U bus_ref The outer loop of the energy storage device is the DC bus voltage, and the inner loop is the PID control of the energy storage device charging and discharging current, so that the actual value of the DC bus voltage U bus Able to track and approach the DC bus voltage reference value U in real time bus_ref ; H. Set the actual value of DC bus voltage U bus The minimum DC bus voltage U min , DC bus voltage rated value U ref , DC bus voltage maximum value U max For comparison, when U min ≤U bus <U ref If U ref <U bus ≤U max If U bus =U ref When the POSITION is reached, the process proceeds to step I or step J; I. The actual value of the DC bus voltage U bus and the minimum DC bus voltage U min , the maximum voltage U of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t max (t) is compared, when U min ≤U bus ≤U max (t), the energy storage device is determined to discharge according to the set droop control curve and the process goes to step K; otherwise, the hydrogen production device is determined to operate in the maximum hydrogen production efficiency range and the process goes to step K; J. The actual value of the DC bus voltage U bus with U min (t) is the minimum voltage U of the energy storage device when charging the isolated island wind power hydrogen production system at time t min (t), maximum DC bus voltage U max For comparison, when U min (t)≤U bus ≤U max When the energy storage device is charged according to the set droop control curve, the process goes to step K; otherwise, the hydrogen production device is determined to be operating in the maximum hydrogen production efficiency range and the process goes to step K; K. Determine the reference power P of the hydrogen production device el_ref , and proceed to step L; L, according to the reference power P of the hydrogen production device el_ref The outer loop of the hydrogen production device is the hydrogen production power, and the inner loop is the PID control of the alkaline electrolyzer working current, so that the hydrogen production power P el Able to track and approach the reference power P of the hydrogen production device in real time el_ref , thereby realizing improved voltage-power droop control of the hydrogen production device, and entering step M; M. Monitor whether the wind speed changes according to the set cyclic control period. If so, return to step A, otherwise return to step H.

2. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 1 is characterized in that: The mathematical model of wind turbines used in the improved voltage-power control method of the isolated wind power hydrogen production system is: In formula (1), P m is the output power of the fan, W; ρ is the air density; C p is the wind energy utilization coefficient; v is the wind speed; R is the radius of the wind rotor; θ is the pitch angle of the wind rotor blade; ω is the rotation speed of the gear structure; λ is the tip speed ratio of the wind rotor blade; λ1 is an intermediate variable, which can be calculated from λ; the values ​​of the polynomial coefficients are: c1=0.5176, c2=116, c3=0.4, c4=5, c5=21, c6=0.0068.

3. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 1 is characterized in that: The mathematical model of the hydrogen production device used in the improved voltage-power control method of the isolated wind power hydrogen production system is: the output voltage U el The formula is: In formula (2), U el is the output voltage of a single alkaline electrolyzer; U rev is the reversible voltage of the alkaline electrolytic cell; r1, r2 are ohmic resistance parameters; T el is the working temperature of the alkaline electrolyzer; k el , is the empirical parameter of overpressure of alkaline electrolyzer; S el is the electrode surface area of ​​the alkaline electrolytic cell; I el is the working current of the alkaline electrolyzer; Reversible voltage U of alkaline electrolyzer rev for: U rev =U ro -K rev (T el -298.15) (3) In formula (3), U ro is the reversible voltage of the alkaline electrolyzer under standard conditions; K rev is the temperature empirical coefficient of the reversible voltage; The voltage of a single alkaline electrolytic cell is small, so multiple alkaline electrolytic cells need to be connected in series. The total output voltage of the series connection is: U elc =n c U el (4) In formula (4), U elc is the total output voltage when multiple alkaline electrolytic cells are connected in series; n c is the number of alkaline electrolytic cells connected in series; Hydrogen production efficiency η of alkaline electrolyzer el Depends on the current efficiency η of the alkaline electrolyzer I and the voltage efficiency η of the alkaline electrolyzer V , when the temperature and pressure are constant, the hydrogen production efficiency of the alkaline electrolyzer is el It can be expressed as: or el =the I or V (5) Voltage efficiency η of alkaline electrolyzer V The formula is as follows: η V =U tn / IN el ×100% (6) In formula (6), U el is the output voltage of a single alkaline electrolyzer, V; U tn It is the thermal neutral voltage, usually stable at 1.482V; Current efficiency η of alkaline electrolyzer I The formula is as follows: In formula (7), I el is the working current of the alkaline electrolyzer, A; S el is the electrode surface area of ​​the alkaline electrolytic cell, m 2 ; is an empirical parameter.

4. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 1 is characterized in that: The insulation critical wind speed v1 in step B is the average wind speed v when the wind power generation power of the wind turbine set in the isolated island wind power hydrogen production system without energy storage device is the insulation power of the hydrogen production device; the rated critical wind speed v2 in step C is the average wind speed v when the wind power generation power of the wind turbine set in the isolated island wind power hydrogen production system without energy storage device is the rated power of the hydrogen production device.

5. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 1 is characterized in that: The method for determining the DC bus voltage variation ΔU in step D is: D1. Establish an isolated wind power hydrogen production system model without energy storage device, and obtain the DC bus voltage waveform when the average wind speed ranges from 5m / s to 12m / s; D2. Based on the DC bus voltage waveform, the relationship curve between the average wind speed and the DC bus voltage is obtained. The numerical relationship between the average wind speed v and the DC bus voltage change ΔU is obtained by fitting the relationship curve: In formula (8), v1 is the insulation critical wind speed when the wind power generation power is the insulation power of the hydrogen production device; v2 is the rated critical wind speed when the wind power generation power is the rated power of the hydrogen production device; a1, b1, c1, a2, b2, c2 are expression coefficients, which can be obtained by curve fitting; ΔU is the change in DC bus voltage.

6. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 5 is characterized in that: The method for determining the actual compensation amount ΔU' of the DC bus voltage in step E is as follows: the actual compensation amount ΔU' of the DC bus voltage is obtained by multiplying the DC bus voltage change ΔU by the compensation coefficient. In formula (9), k1 and k2 are compensation coefficients, and their value range is [-0.6, 0].

7. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 1 or 5, characterized in that: The DC bus voltage reference value U in step F bus_ref The method to determine is: F1. Obtain the charge and discharge current I of the energy storage device based on the droop control curve of the energy storage device b and DC bus voltage U' before compensation bus_ref The relationship between them is: In formulas (10), (11), and (12), U min (t) is the minimum voltage value of the energy storage device of the isolated island wind power hydrogen production system when charging at time t, U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t; U ref is the rated value of the DC bus voltage; ΔU S is the voltage dead zone; SOC max The maximum state of charge of the energy storage device, SOC min SOC is the minimum state of charge of the energy storage device; i is the SOC value of the energy storage device at the current moment; define I b >0 means discharge, I b <0 is charging; m is the droop coefficient of the energy storage device charging and discharging based on voltage-current droop control; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; I bmax is the maximum discharge current of the energy storage device, I bmin It is the minimum value of charging current of the energy storage device; F2, DC bus voltage reference value U bus_ref To compensate the DC bus voltage U' bus_ref The sum of the actual compensation value ΔU' of the DC bus voltage, that is, U bus_ref =U b ' us_ref +ΔU'.

8. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to any one of claims 1 to 3, characterized in that: The actual value U of the DC bus voltage in step H, step I, and step J bus The output power of the hydrogen production device satisfies the following relationship: In formula (13) and (14), P elN is the maximum power of the hydrogen production device, i.e. the rated power; P(t) is the output power of the hydrogen production device at time t; U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t, U min (t) is the minimum voltage value of the energy storage device of the isolated wind power hydrogen production system when charging at time t; l(t) is the discharge droop coefficient of the energy storage device at time t based on voltage-power droop control, and q(t) is the charging droop coefficient of the energy storage device at time t based on voltage-power droop control.

9. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 8 is characterized in that: The reference power P of the hydrogen production device in step K el_ref The method for determining is: the reference power P of the hydrogen production device when the hydrogen production device in step H is operated at the insulation power el_ref The insulation power P of the hydrogen production device elmin The reference power P of the hydrogen production device when the hydrogen production device in step H is operated at rated power el_ref is the rated power P of the hydrogen production device elN The reference power P of the hydrogen production device in step I and step J is when the hydrogen production device operates in the maximum hydrogen production efficiency range. el_ref is the hydrogen production power P corresponding to the maximum hydrogen production efficiency range of the hydrogen production device elmax .

10. The improved voltage-power control method for an isolated island wind power hydrogen production system considering the influence of high sensitivity factors according to claim 8, characterized in that: The reference power P of the hydrogen production device in step K el_ref The method to determine is: In step I, when U min ≤U bus ≤U max (t), the reference power P of the hydrogen production device el_ref and the actual value of the DC bus voltage U bus The relationship is expressed as: In step J, when U min (t)≤U bus ≤U max When the reference power of hydrogen production device is P el_ref and the actual value of the DC bus voltage U bus The relationship is expressed as: In formula (15) and (16), P el_ref is the reference power of the hydrogen production device; P elmax is the hydrogen production power corresponding to the maximum hydrogen production efficiency range of the hydrogen production device; P elN is the rated power of the hydrogen production device; h1 is U min ≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system at time (t); U min (t) is the minimum voltage value of the energy storage device of the isolated island wind power hydrogen production system when charging at time t, U max (t) is the maximum voltage of the energy storage device of the isolated island wind power hydrogen production system when discharging at time t; U max is the maximum value of the DC bus voltage, U min is the minimum DC bus voltage; P elmin is the insulation power of the hydrogen production device; h2 is U min (t)≤U bus ≤U max The droop coefficient of the energy storage device based on voltage-power droop control in the isolated island wind power hydrogen production system.

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