CN110611332B - Energy storage device of offshore wind power system and control method thereof - Google Patents

Abstract

The invention discloses an energy storage device of an offshore wind power system, which comprises: the system comprises an offshore wind field module, a power transformation module, a land power generation transmission module and a hybrid energy storage module; the offshore wind field module is respectively connected with the power generation module and the hybrid energy storage module and is used for outputting power to the power generation module and the hybrid energy storage module; the power transformation module is connected with the land power generation transmission module and the hybrid energy storage module and is used for transforming the power output by the offshore wind field module and outputting the power to the land power generation transmission module and the hybrid energy storage module; the hybrid energy storage module is used to absorb or supply power to the offshore wind farm module. The invention effectively solves the problem of distributed dispersion of large-scale land wind power bases and open sea wind power stations, provides inertia response for wind power station systems through the hybrid energy storage unit, combines hybrid energy storage and virtual inertia control of the offshore wind power stations through the hybrid energy storage unit by adopting a fuzzy PID control algorithm, and makes full use of the charge and discharge functions of the hybrid energy storage module to enable the power grid to be more stable.

Description

An offshore wind power system energy storage device and its control method

technical field

The invention relates to the technical field of wind power generation, in particular to an energy storage device for an offshore wind power system and a control method thereof.

Background technique

Facing the dual crises of energy shortage and environmental pollution, vigorously developing renewable energy and optimizing energy structure has become an important direction to promote the sustainable development of global economy-energy-environment. As a non-polluting and renewable clean energy, wind energy has great development potential and has been valued and favored by more and more countries. In recent years, with the encouragement and preferential policies of the governments of various countries, wind power has become the fastest growing renewable energy. The continuous expansion of wind power generation will have a profound impact on the improvement of energy structure and environmental issues.

With the continuous improvement and maturity of offshore wind turbine installation and manufacturing technology, its stand-alone capacity has been continuously improved, and the scale of offshore wind farms has expanded accordingly, and has gradually developed towards offshore or even deep seas far away from land and with more intensive wind energy resources. Due to the unique geographical location of offshore wind farms, the long-distance transmission and grid connection of offshore wind power have become one of the key factors restricting the development of offshore wind power.

At present, the use of high-voltage direct current transmission (abbreviation: "HVDC") technology has solved the problem of long-distance transmission and grid connection. HVDC technology is very suitable for long-distance transmission of electric energy, and has the advantages of low cost, low power consumption, and relatively mature technology. As the penetration rate of wind power increases, the stability of the power grid also increases.

Contents of the invention

The invention provides an excitation control device and a use method of a synchronous motor to solve the technical problem in the prior art that the stability of the power grid is poor with the increase of the wind power penetration rate.

The invention provides an energy storage device for an offshore wind power system, including: an offshore wind field module, a power transformation module, an onshore power generation transmission module, and a hybrid energy storage module;

The offshore wind farm module is respectively connected to the conversion module and the hybrid energy storage module for outputting power to the conversion module and the hybrid energy storage module;

The power conversion module is connected to the onshore power generation transmission module and the hybrid energy storage module, and is used to convert the power output by the offshore wind farm module, and then output it to the onshore power generation transmission module and the hybrid energy storage module;

The hybrid energy storage module is used to absorb or supply the power of the offshore wind farm module;

The onshore power generation transmission module is used for grid-connecting the power output by the offshore wind farm module to the land power grid.

Further, the offshore wind farm module includes: an array of wind turbines; the wind turbines include: wind turbines, gearboxes, double-fed wind turbines, wind power rectifiers, wind power inverters, and first transformers;

The power transformation module includes: a first AC bus, a second transformer, a second AC bus, and a high-voltage direct current transmission unit;

The onshore power generation transmission module includes: an onshore power generation transmission unit and a third AC bus;

The hybrid energy storage module includes: a phase-locked loop, a data processing unit, a hybrid energy storage unit, and a DC bus;

The output end of the wind turbine is connected to the input shaft of the gear box; the output shaft of the gear box is connected to the input end of the double-fed fan; the output end of the double-fed fan is respectively connected to the AC input end of the wind power rectifier, The input end of the first transformer is connected; the DC output end of the wind power rectifier is connected to the DC input end of the wind power inverter, and the DC output end of the wind power rectifier is connected to the DC bus; the AC of the wind power inverter The output terminal is connected to the input terminal of the first transformer; the output terminal of the first transformer is connected to the first AC bus; the input terminal of the second transformer is connected to the first AC bus, and the output terminal is connected to the first AC bus. The second AC bus is connected; the output end of the second AC bus is connected to the input end of the high-voltage direct current transmission unit; the output end of the high-voltage direct current transmission unit is connected to the input end of the phase-locked loop; the The output end of the phase-locked loop is respectively connected to the input end of the third AC bus and the data processing unit; the output end of the third AC bus is respectively connected to the input end of the land power generation transmission unit and the data processing unit; The output end of the DC bus is connected to the input end of the data processing unit; the output end of the data processing unit is connected to the input end of the hybrid energy storage unit, and the data processing unit is based on the phase-locked loop The obtained power angle and frequency value, the current value and voltage value obtained from the third AC bus, the current value and voltage value obtained from the DC bus, and output the voltage value directly acting on the hybrid energy storage unit and power value, charge the hybrid energy storage unit; the charging and discharging terminal of the hybrid energy storage unit is connected to the DC bus, and the hybrid energy storage unit charges the DC bus based on its own voltage value and power value discharge.

Further, the hybrid energy storage unit includes: a direct bus access terminal, a twenty-fourth resistor, a thirty-ninth resistor, a twenty-fifth reactance, a thirty-first reactance, a twenty-sixth diode, a second Seventeenth diode, thirty-second diode, thirty-third diode, twenty-eighth capacitor, thirty-fourth capacitor and hybrid energy storage battery;

The anode of the DC bus access terminal is respectively connected to one end of the twenty-fourth resistor, one end of the thirty-fourth capacitor, the anode of the thirty-second diode, and the first pin of the hybrid energy storage battery, so The negative pole of the DC bus access terminal is respectively connected to the other end of the thirty-fourth capacitor, the negative pole of the thirty-third diode, the positive pole of the twenty-seventh diode, one end of the twenty-eighth capacitor, the mixed storage connected to the first pin of the battery; the other end of the twenty-fourth resistor is connected to one end of the twenty-fifth reactance; the other end of the twenty-fifth reactance is connected to the twenty-sixth two The positive pole of the pole tube and the negative pole of the twenty-seventh diode are connected; the negative pole of the twenty-sixth diode is respectively connected with the other end of the twenty-eighth capacitor and the second pin of the hybrid energy storage battery ; The anode of the thirty-third diode is respectively connected to the anode of the thirty-second diode and one end of the thirty-first reactance; the other end of the thirty-first reactance is connected to the third One end of the tenth resistor is connected; the other end of the thirtieth resistor is connected to the second pin of the combined energy storage battery; the input end of the hybrid energy storage battery is connected to the data processing unit.

Further, the data processing unit includes: a virtual inertia control unit, a power frequency calculation unit, a voltage calculation unit, a power calculation unit, a first adder, and a second adder;

The input end of the power frequency calculation unit is respectively connected to the output end of the third AC bus and the output end of the phase-locked loop, and the output end is respectively connected to the input end of the virtual inertia control unit and the input end of the first adder , the power frequency calculation unit is based on the grid voltage angle θ obtained from the phase-locked loop, the grid voltage value U _abc and the grid current value I _abc obtained from the third AC bus, and calculates to the all through 3/2 transformation The first adder outputs a grid-connected power value P _g , and outputs a frequency reference value f _ref to the virtual inertia control unit based on the grid-connected power value P _g ; the input terminal of the virtual inertia control unit is connected to the phase-locked loop connected to the output end of the second adder, the output end is connected to the input end of the second adder, the virtual inertia control unit is based on the frequency value f _means and the frequency reference value f _ref obtained from the phase-locked loop, and is calculated by the PID control algorithm Outputting a power value P _ess to the second adder; the input terminal of the power calculation unit is connected to the output terminal of the DC bus, and the voltage calculation unit is based on the voltage value U ₀ and the current obtained from the DC bus value I ₀ , output the power value P ₀ to the first adder after power calculation; the output terminal of the first adder is connected to the input terminal of the voltage calculation unit, and the first adder will grid-connected power The value P _g and the power value P ₀ are added and calculated to output the power value _Ph to the voltage calculation unit; the output terminal of the voltage calculation unit is connected to the input terminal of the hybrid energy storage unit, and the voltage calculation unit is based on the The power value P _h is output to the hybrid energy storage unit through a DC/DC converter voltage and current double closed-loop control algorithm to input a reference value U ^* ; the output terminal of the second adder is connected to the hybrid energy storage unit The input end is connected, and the second adder adds the power value P _ess and the power deviation value _△ P _soc to the hybrid energy storage unit and then outputs the power input reference value P ^* , wherein the power deviation value _△ P _soc is a power deviation value calculated by adding the power value Ph _h to the real-time power value P _c of the hybrid energy storage unit after passing through a high-pass filter control algorithm.

The present invention also provides a control method for an energy storage device of an offshore wind power system: comprising the following steps:

Step 1: Get the voltage value U ₀ and current value I ₀ from the DC bus; get the grid voltage angle θ and frequency value f _means from the phase-locked loop; get the grid voltage value U _abc and the grid current value from the third AC bus I _abc ; Obtain the real-time power value P _c from the hybrid energy storage unit;

Step 2: The power frequency calculation unit obtains the grid-connected power value P _g through 3/2 conversion calculation according to the grid voltage angle θ, the grid voltage value U _abc and the grid current value I _abc , and calculates the grid-connected power value P g according to the grid-connected power value P _g obtains the frequency reference value f _ref ;

The virtual inertia control unit calculates and obtains the power value P _ess through the PID control algorithm according to the frequency value f _means and the frequency reference value f _ref ;

The power calculation unit obtains a power value P ₀ through power according to the voltage value U ₀ and the current value I ₀ ;

Step 3: Add the power value P ₀ and the grid-connected power value P _g to obtain the power value P _h ; the power value P _h is combined with the power value P _c after the high-pass filter control algorithm and the addition operation in turn Perform addition calculation to obtain the power deviation value _△ P _soc ;

Step 4: According to the power value P _h , the voltage calculation unit sequentially undergoes a high-pass filter control algorithm, an addition operation, and obtains a voltage input reference value U ^* ; performs an addition calculation on the power value P _ess and a power deviation value _△ P _soc , obtain a power input reference value P ^* ;

Step 5: setting the battery capacity of the hybrid energy storage unit according to the power input reference value P ^* ; controlling the output or output voltage and current of the hybrid energy storage unit according to the voltage input reference value U ^* ;

Step 6: Obtain the real-time power value P _w of the offshore wind farm module; obtain the expected grid-connected power P _out ;

Step 7: When the power value P _w is greater than the grid power P _out , the hybrid energy storage unit switches to the energy absorption mode, and absorbs the power in the offshore wind farm module through the DC bus;

When the power value P _w is smaller than the grid power P _out , the hybrid energy storage unit switches to an energy supply mode, and transmits power to the offshore wind farm module through the DC bus.

Further, in the step 2, the virtual inertia control unit calculates and obtains the power value P _ess through the PID control algorithm with three regulators P, I, and D according to the frequency value f _means and the frequency reference value f _ref .

Further, in the step 5, the method of controlling the output of the hybrid energy storage unit or the output voltage and current according to the voltage input reference value U ^* is as follows: the voltage input reference value U ^* is used as a DC/DC conversion The input parameters of the voltage and current double closed-loop control algorithm of the DC/DC converter are used to control the output or output voltage and current of the hybrid energy storage unit through the output of the DC/DC converter voltage and current double closed-loop control algorithm.

Further, the DC/DC converter voltage and current double closed-loop control algorithm in step 5 is a DC/DC converter voltage and current double closed-loop control algorithm using a fuzzy PID control algorithm.

Beneficial effects of the present invention:

The invention utilizes the HVDC technology to effectively solve the scattered distribution of large-scale onshore wind power bases and offshore wind farms, concentrates the scattered wind power over long distances, and sends it across regions. Inertia response is provided, and the hybrid energy storage module adopts fuzzy PID control, which combines the hybrid energy storage with the virtual inertia control of the offshore wind farm, and makes full use of the charging and discharging function of the hybrid energy storage module to make the power grid more stable.

Description of drawings

The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the accompanying drawings:

Fig. 1 is a schematic circuit diagram of an energy storage device for an offshore wind power system in the present invention;

Fig. 2 is a schematic circuit diagram of a hybrid energy storage unit in the present invention;

Fig. 3 is a control algorithm structural diagram of the output frequency reference value f _ref in the present invention;

Fig. 4 is fuzzy PID control algorithm structural diagram among the present invention;

5 is a structural diagram of a DC/DC converter voltage and current double closed-loop control algorithm in the present invention;

Fig. 6 is the algorithm structural diagram that power value _Ph is processed among the present invention;

Fig. 7 is a structural diagram of the virtual inertia control algorithm based on energy storage in the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

As shown in Figure 1, an embodiment of the present invention provides an energy storage device for an offshore wind power system, including: an offshore wind farm module, a power transformation module, an onshore power generation transmission module, and a hybrid energy storage module;

The offshore wind farm module includes: 45 groups of array wind turbines; the 45 groups of wind turbines include: wind turbine 45, gearbox 46, double-fed fan 47, wind power rectifier 1, wind power inverter 2, and first transformer 48;

The power transformation module includes: a first AC bus 3, a second transformer 4, a second AC bus 6, and a high-voltage direct current transmission unit 36;

The onshore power generation transmission module includes: an onshore power generation transmission unit 19, a third AC bus 21;

The hybrid energy storage module includes: a phase-locked loop 37, a data processing unit, a hybrid energy storage unit 5, and a DC bus 42;

The output end of the wind turbine 45 is connected with the input shaft of the gear box 46; the output shaft of the gear box 46 is connected with the input end of the doubly-fed fan 47; The input end of the transformer 48 is connected; the DC output end of the wind power rectifier 1 is connected to the DC input end of the wind power inverter 2, and the DC output end of the wind power rectifier 1 is connected to the DC bus 42; the AC output end of the wind power inverter 2 is connected to the first transformer The input end of 48 is connected; the output end of the first transformer 48 is connected with the first AC bus 3; the input end of the second transformer 4 is connected with the first AC bus 3, and the output end is connected with the second AC bus 6; the second AC bus The output terminal of 6 is connected with the input terminal of HVDC transmission unit 36; the output terminal of HVDC transmission unit 36 is connected with the input terminal of PLL 37; the output terminal of PLL 37 is respectively connected with the third AC bus 21 and the data processing unit The input end of the third AC bus 21 is connected with the input end of the land power generation transmission unit 19 and the data processing unit respectively; the output end of the DC bus 42 is connected with the input end of the data processing unit; the output of the data processing unit end is connected with the input end of the hybrid energy storage unit 5, and the data processing unit is based on the power angle and the frequency value obtained from the phase-locked loop 37, the current value and the voltage value obtained from the third AC bus 21, and the current obtained from the DC bus 42 value and voltage value, and output the voltage value and power value directly acting on the hybrid energy storage unit 5 to charge the hybrid energy storage unit 5; the charging and discharging terminals of the hybrid energy storage unit 5 are connected to the DC bus 42, and the hybrid energy storage unit 5 Charge and discharge the DC bus 42 based on its own voltage value and power value;

Wherein, the data processing unit includes: virtual inertia control unit 38, power frequency calculation unit 39, voltage calculation unit 40, power calculation unit 41, first adder 43, second adder 44;

The input end of the power frequency calculation unit 39 is respectively connected with the output end of the third AC bus 21 and the output end of the phase-locked loop 37, and the output end is respectively connected with the input end of the virtual inertia control unit 38 and the input end of the first adder 43, The power frequency calculation unit 39 is based on the grid voltage angle θ obtained from the phase-locked loop 37, the grid voltage value U _abc and the grid current value I _abc obtained from the third AC bus 21, and calculates the power to the first adder 43 through 3/2 conversion. Output the grid-connected power value P _g , and output the frequency reference value f _ref to the virtual inertia control unit 38 based on the grid-connected power value P _g ; the input terminal of the virtual inertia control unit 38 is connected to the output terminal of the phase-locked loop 37, and the output terminal is connected to the output terminal of the phase-locked loop 37. The input terminal of the second adder 44 is connected, and the virtual inertia control unit 38 outputs the power value P _ess to the second adder 44 through PID control algorithm calculation based on the frequency value f _means obtained from the phase-locked loop 37 and the frequency reference value f _ref The input terminal of the power calculation unit 41 is connected to the output terminal of the DC bus 42, and the voltage calculation unit 40 outputs the power value to the first adder 43 through power calculation based on the voltage value U ₀ and the current value I ₀ obtained from the DC bus 42 P ₀ ; the output end of the first adder 43 is connected to the input end of the voltage calculation unit 40, and the first adder 43 adds the grid-connected power value P _g and the power value P ₀ to the voltage calculation unit 40 to output the power value P _h ; the output end of the voltage calculation unit 40 is connected to the input end of the hybrid energy storage unit 5, and the voltage calculation unit 40 outputs voltage to the hybrid energy storage unit 5 through the DC/DC converter voltage and current double closed-loop control algorithm based on the power value _Ph Input the reference value U ^* ; the output end of the second adder 44 is connected to the input end of the hybrid energy storage unit 5, and the second adder 44 adds the power value P _ess and the power deviation value ΔP _soc to the hybrid energy storage unit 5 Output power input reference value P ^* , where the power deviation value △P _soc is the power deviation value calculated by adding the power value P _h to the real-time power value P _c of the hybrid energy storage unit 5 after passing through the high-pass filter control algorithm.

As shown in Figure 2, the hybrid energy storage unit 5 includes: a DC bus access terminal 23, a twenty-fourth resistor 24, a thirty-fifth resistor 30, a twenty-fifth reactance 25, a thirty-first reactance 31, a twenty-first Six diodes 26, twenty-seventh diodes 27, thirty-second diodes 32, thirty-third diodes 33, twenty-eighth capacitors 28, thirty-fourth capacitors 34 and hybrid energy storage battery 29;

The positive pole of the DC bus access terminal 23 is respectively connected to one end of the twenty-fourth resistor 24, one end of the thirty-fourth capacitor 34, the positive pole of the thirty-second diode 32, and the first pin of the hybrid energy storage battery 29 , the negative pole of the DC bus access terminal 23 is connected to the other end of the thirty-fourth capacitor 34, the negative pole of the thirty-third diode 33, the positive pole of the twenty-seventh diode 27, and the twenty-eighth capacitor 28 respectively. One end is connected to the first pin of the hybrid energy storage battery 29; the other end of the twenty-fourth resistor 24 is connected to one end of the twenty-fifth reactance 25; The positive pole of pole tube 26, the negative pole of twenty-seventh diode 27 are connected; connection; the positive pole of the thirty-third diode 33 is connected with the positive pole of the thirty-second diode 32 and one end of the thirty-first reactance 31 respectively; the other end of the thirty-first reactance 31 is connected with the thirty-first resistor 30 One end of the thirtieth resistor 30 is connected to the second pin of the combined energy storage battery; the input end of the hybrid energy storage battery 29 is connected to the data processing unit. This circuit can realize charging and discharging of the hybrid energy storage battery 29 .

The control method of the energy storage device of the offshore wind power system of the present invention is as follows:

A control method for an energy storage device of an offshore wind power system: comprising the following steps:

Step 1: Obtain voltage value U ₀ and current value I ₀ from DC bus 42; obtain grid voltage angle θ and frequency value f _means from phase-locked loop 37; acquire grid voltage value U _abc and The grid current value I _abc ; obtain the real-time power value P _c from the hybrid energy storage unit 5 ;

Step 2: The power frequency calculation unit 39 obtains the grid-connected power value P _g through 3/2 conversion calculation according to the grid voltage angle θ, the grid voltage value U _abc and the grid current value I _abc , and according to the grid-connected power value P _g obtains the frequency reference value f _ref ;

The virtual inertia control unit 38 calculates and obtains the power value P _ess through the PID control algorithm with three regulators P, I, and D according to the frequency value f _means and the frequency reference value f _ref ;

The power calculation unit 41 obtains a power value P ₀ through power according to the voltage value U ₀ and the current value I ₀ ;

Step 3: Add the power value P ₀ and the grid-connected power value P _g to obtain the power value P _h ; the power value P _h is combined with the power value P _c after the high-pass filter control algorithm and the addition operation in turn Perform addition calculation to obtain the power deviation value △P _soc ;

Step 4: According to the power value P _h , the voltage calculation unit 40 sequentially undergoes a high-pass filter control algorithm, an addition operation, and obtains a voltage input reference value U ^* ; and performs an addition calculation on the power value P _ess and the power deviation value ΔP _soc , to obtain the power input reference value P ^* ;

Step 5: Set the battery capacity of the hybrid energy storage unit 5 according to the power input reference value P ^* ; input the voltage input reference value U ^* as the input voltage and current double closed-loop control algorithm of the DC/DC converter using the fuzzy PID control algorithm Parameters, control the output of the hybrid energy storage unit 5 or the output voltage and the size of the current through the output of the DC/DC converter voltage and current double closed-loop control algorithm;

Step 6: Obtain the real-time power value P _w of the offshore wind farm module; obtain the expected grid-connected power P _out ;

Step 7: When the power value P _w is greater than the grid power P _out , the hybrid energy storage unit 5 switches to the energy absorption mode, and absorbs the power in the offshore wind farm module through the DC bus 42;

When the power value P _w is smaller than the grid power P _out , the hybrid energy storage unit 5 switches to an energy supply mode, and transmits power to the offshore wind farm module through the DC bus 42 .

What Fig. 3-Fig. 7 shows is the structural representation of the control algorithm used in the control method of the present invention, the control algorithm structural diagram of the output frequency reference value fref as shown in Fig. 3, at first obtain grid voltage by the effect of phase-locked loop PLL Angle θ, the grid voltage U _abc and grid current I _abc are transformed into the dq coordinate system through 3/2 transformation, and then the voltage and current on the dq coordinate system are multiplied to obtain their respective powers and added to obtain the grid-connected target reference power P _g , and then the frequency reference value f _ref is obtained through power-to-frequency calculation.

As shown in Figure 4, the fuzzy PID power control structure diagram, where P _b ^* not only represents the battery power P _sb ^* , but also represents the super capacitor power P _sc ^* , the output power Pc is fed back and the mixed energy storage power of the input power P _b ^* The deviation value ΔP _SOC acts on three parts, one part is used as an input value of the fuzzy control algorithm, the other part is differentiated to obtain the differential change rate _Ec as the second input quantity of the fuzzy control algorithm, and the last part is the input value of the PID controller , and K _P , K _i , K _d respectively represent the three parameters of the proportional integral differential link as the input value of the PID controller, and the obtained voltage value U ^* is passed through the hybrid energy storage unit to obtain the power value P _c after passing through the power sensor as feedback.

As shown in Figure 5, the DC/DC converter voltage and current double closed-loop control structure diagram, the difference between the U ^* obtained by the PID controller and the voltage value U _soc provided by the DC/DC converter is used as the input of the fuzzy PID control algorithm, and the fuzzy PID control algorithm is controlled by the fuzzy The current value I ^* obtained by the PID control algorithm and the current value I provided by the DC/DC converter are used as the input of the fuzzy PID control algorithm, and then the control pulse output by the switch controller is used as the switch conduction signal of the DC/DC converter , the DC/DC converter is connected to the hybrid energy storage unit.

As shown in the power current calculation module diagram in Figure 6, the power value P _h obtained in Figure 1 is obtained by the high-pass filter control algorithm to obtain the supercapacitor power reference value P _sc ^* and the battery power reference value P _sb ^* , where the supercapacitor power Reference value P _sc ^* and battery power reference value P _sb ^* are denoted by P _b ^* in Fig. 4, U ^* obtained by fuzzy PID control algorithm in Fig. 4 is used as the input value of DC/DC voltage and current double closed-loop control in Fig. 5.

As shown in Figure 7, it is based on the integrated virtual inertia control diagram, where f _means is the frequency value provided by the phase-locked loop PLL, K _p is the proportional adjustment coefficient, K _i is the integral adjustment coefficient, K _d is the differential adjustment coefficient, P _ess The power output value is controlled by the virtual inertia PID, and the frequency deviation of the feedback system is used to control the energy storage power output through the proportional integral differential (PID) controller, that is: P _ess ＝-K _p Δf-K _i ∫Δf-K _d df/dt . The output power P ^* consists of two parts, one part is the output energy storage power Pess based on PID control, and the other part is the hybrid energy storage power deviation value ΔP _soc . Among them, ΔP _soc includes two parts, the first part is the battery power deviation ΔP _sb , and the second part is the supercapacitor power deviation ΔP _sc , both of which are used as the input value of the hybrid energy storage unit ESS.

Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall into the scope of the appended claims. within the limited range.

Claims (5)

1. An offshore wind power system energy storage device, comprising: the system comprises an offshore wind field module, a power transformation module, a land power generation transmission module and a hybrid energy storage module;

the offshore wind field module is respectively connected with the power transformation module and the hybrid energy storage module and is used for outputting power to the power transformation module and the hybrid energy storage module;

the power transformation module is connected with the land power generation transmission module and the hybrid energy storage module and is used for transforming the power output by the offshore wind field module and outputting the power to the land power generation transmission module and the hybrid energy storage module;

the hybrid energy storage module is used for absorbing or supplying power to the offshore wind farm module;

the land power generation transmission module is used for connecting the power output by the offshore wind field module to a land power grid;

the offshore wind farm module comprises: an array of wind turbine units; the wind turbine includes: the wind turbine, the gear box, the doubly-fed wind turbine, the wind power rectifier, the wind power inverter and the first transformer;

the power transformation module includes: the device comprises a first alternating current bus, a second transformer, a second alternating current bus and a high-voltage direct current transmission unit;

the land power generation transmission module includes: a land power generation transmission unit and a third alternating current bus;

the hybrid energy storage module includes: the device comprises a phase-locked loop, a data processing unit, a hybrid energy storage unit and a direct current bus;

the output end of the wind turbine is connected with the input shaft of the gear box; an output shaft of the gear box is connected with an input end of the double-fed fan; the output end of the doubly-fed wind turbine is respectively connected with the alternating current input end of the wind power rectifier and the input end of the first transformer; the direct current output end of the wind power rectifier is connected with the direct current input end of the wind power inverter, and the direct current output end of the wind power rectifier is connected with the direct current bus; the alternating current output end of the wind power inverter is connected with the input end of the first transformer; the output end of the first transformer is connected with the first alternating current bus; the input end of the second transformer is connected with the first alternating current bus, and the output end of the second transformer is connected with the second alternating current bus; the output end of the second alternating current bus is connected with the input end of the high-voltage direct current transmission unit; the output end of the HVDC transmission unit is connected with the input end of the phase-locked loop; the output end of the phase-locked loop is respectively connected with the third alternating current bus and the input end of the data processing unit; the output end of the third alternating current bus is respectively connected with the input ends of the land power generation transmission unit and the data processing unit; the output end of the direct current bus is connected with the input end of the data processing unit; the output end of the data processing unit is connected with the input end of the hybrid energy storage unit, and the data processing unit outputs a voltage value and a power value directly acting on the hybrid energy storage unit to charge the hybrid energy storage unit based on a power angle and a frequency value obtained from the phase-locked loop, a current value and a voltage value obtained from the third alternating current bus, and a current value and a voltage value obtained from the direct current bus; the charging and discharging end of the hybrid energy storage unit is connected with the direct current bus, and the hybrid energy storage unit charges and discharges the direct current bus based on the self voltage value and the power value;

the hybrid energy storage unit includes: a direct bus access terminal, a twenty-fourth resistor, a thirty-fourth resistor, a twenty-fifth reactance, a thirty-first reactance, a twenty-sixth diode, a twenty-seventh diode, a thirty-second diode, a thirty-third diode, a twenty-eighth capacitor, a thirty-fourth capacitor, and a hybrid energy storage battery;

the positive electrode of the direct current bus access end is respectively connected with one end of the twenty-fourth resistor, one end of the thirty-fourth capacitor, the positive electrode of the thirty-second diode and the first pin of the hybrid energy storage battery, and the negative electrode of the direct current bus access end is respectively connected with the other end of the thirty-fourth capacitor, the negative electrode of the thirty-third diode, the positive electrode of the twenty-seventh diode, one end of the twenty-eighth capacitor and the first pin of the hybrid energy storage battery; the other end of the twenty-fourth resistor is connected with one end of the twenty-fifth reactor; the other end of the twenty-fifth reactor is respectively connected with the anode of the twenty-sixth diode and the cathode of the twenty-seventh diode; the negative electrode of the twenty-sixth diode is respectively connected with the other end of the twenty-eighth capacitor and a second pin of the hybrid energy storage battery; the positive electrode of the thirty-third diode is connected with the positive electrode of the thirty-second diode and one end of the thirty-first reactor respectively; the other end of the thirty-first reactor is connected with one end of the thirty-first resistor; the other end of the thirty-second resistor is connected with a second pin of the combined energy storage battery; the input end of the hybrid energy storage battery is connected with the data processing unit;

the data processing unit includes: the virtual inertia control unit, the power frequency calculation unit, the voltage calculation unit, the power calculation unit, the first adder and the second adder;

the input end of the power frequency calculation unit is respectively connected with the output end of the third alternating current bus and the output end of the phase-locked loop, the output end of the power frequency calculation unit is respectively connected with the input end of the virtual inertia control unit and the input end of the first adder, and the power frequency calculation unit is based on the power grid voltage angle theta obtained from the phase-locked loop and the power grid voltage value U obtained from the third alternating current bus _abc Grid current value I _abc Outputting a grid-connected power value P to the first adder through 3/2 conversion calculation _g And based on the grid-connected power value P _g Outputting a frequency reference value f to the virtual inertia control unit _ref The method comprises the steps of carrying out a first treatment on the surface of the The input end of the virtual inertia control unit is connected with the output end of the phase-locked loop, the output end of the virtual inertia control unit is connected with the input end of the second adder, and the virtual inertia control unit is based on the frequency value f obtained from the phase-locked loop _means Frequency reference value f _ref Calculating the output power value P to the second adder through a PID control algorithm _ess The method comprises the steps of carrying out a first treatment on the surface of the The input end of the power computing unit is connected with the output end of the direct current bus, and the voltage computing unit is based on a voltage value U obtained from the direct current bus ₀ Current value I ₀ Outputting a power value P to the first adder through power calculation ₀ The method comprises the steps of carrying out a first treatment on the surface of the The output end of the first adder is connected with the input end of the voltage calculation unit, and the first adderThe grid-connected power value P _g Power value P ₀ Performing addition calculation to output power value P to the voltage calculation unit _h The method comprises the steps of carrying out a first treatment on the surface of the The output end of the voltage calculating unit is connected with the input end of the hybrid energy storage unit, and the voltage calculating unit is based on the power value P _h The voltage input reference value U is output to the hybrid energy storage unit through a DC/DC converter voltage-current double closed-loop control algorithm ^* The method comprises the steps of carrying out a first treatment on the surface of the The output end of the second adder is connected with the input end of the hybrid energy storage unit, and the second adder outputs the power value P _ess Power offset value _△ P _soc Adding and outputting power input reference value P to the hybrid energy storage unit ^* Wherein the power offset value _△ P _soc Is the power value P _h The real-time power value P of the hybrid energy storage unit after passing through a high-pass filtering control algorithm _c And carrying out addition calculation to obtain a power deviation value.

2. A control method for an offshore wind power system energy storage device according to claim 1, comprising the steps of:

step 1: obtaining voltage value U from DC bus ₀ And a current value I ₀ The method comprises the steps of carrying out a first treatment on the surface of the Obtaining the power grid voltage angle theta and the frequency value f from the phase-locked loop _means The method comprises the steps of carrying out a first treatment on the surface of the Obtaining a power grid voltage value U from a third alternating current bus _abc And a grid current value I _abc The method comprises the steps of carrying out a first treatment on the surface of the Acquiring real-time power value P from hybrid energy storage unit _c ；

Step 2: the power frequency calculation unit calculates a power grid voltage value U according to the power grid voltage angle theta and the power grid voltage value U _abc Grid current value I _abc Obtaining the grid-connected power value P through 3/2 conversion calculation _g And according to the grid-connected power value P _g Obtaining a frequency reference value f _ref ；

The virtual inertia control unit is used for controlling the virtual inertia according to the frequency value f _means Frequency reference value f _ref The power value P is obtained through calculation of a PID control algorithm _ess ；

The power calculation unit calculates the voltage value U according to the voltage value U ₀ Current value I ₀ Obtaining power value P by power ₀ ；

Step 3: the power value P ₀ And grid-connected power value P _g Adding to obtain power value P _h The method comprises the steps of carrying out a first treatment on the surface of the The power value P _h Sequentially performing high-pass filter control algorithm and addition operation, and then performing addition operation on the obtained value and the power value P _c Performing addition calculation to obtain power deviation value _△ P _soc ；

Step 4: the voltage calculation unit calculates the power value P according to the power value _h The voltage input reference value U is obtained through a high-pass filtering control algorithm and addition operation in sequence ^* The method comprises the steps of carrying out a first treatment on the surface of the The power value P _ess And power offset value _△ P _soc Adding to obtain power input reference value P ^* ；

Step 5: according to the power input reference value P ^* Setting the battery capacity of the hybrid energy storage unit; according to the voltage input reference value U ^* Controlling the output of the hybrid energy storage unit or the voltage and current of the output;

step 6: acquiring real-time power value P of offshore wind farm module _w The method comprises the steps of carrying out a first treatment on the surface of the Acquiring expected grid-connected power P _out ；

Step 7: when the power value P _w Greater than the network power P _out When the hybrid energy storage unit is switched to an energy absorption mode, the power in the offshore wind field module is absorbed through the direct current bus;

when the power value P _w Less than the network power P _out And when the hybrid energy storage unit is switched into an energy supply mode, power is transmitted to the offshore wind field module through the direct current bus.

3. The method for controlling an energy storage device of an offshore wind power system according to claim 2, wherein the virtual inertia control unit in step 2 is configured to control the energy storage device according to the frequency value f _means Frequency reference value f _ref The power value P is obtained by calculation through a PID control algorithm with P, I, D three regulators _ess 。

4. The method for controlling an energy storage device of an offshore wind power system according to claim 2, wherein the reference value U is input according to the voltage in the step 5 ^* The method for controlling the output of the hybrid energy storage unit or the output voltage and current comprises the following steps: input voltage to reference value U ^* As input parameters of the DC/DC converter voltage and current double closed-loop control algorithm, the output quantity of the DC/DC converter voltage and current double closed-loop control algorithm is used for controlling the output of the hybrid energy storage unit or the output voltage and current.

5. The method for controlling an energy storage device of an offshore wind power system according to claim 4, wherein the DC/DC converter voltage-current double closed-loop control algorithm in the step 5 is a DC/DC converter voltage-current double closed-loop control algorithm using a fuzzy PID control algorithm.

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