CN116454937B

CN116454937B - Control method, system, controller and medium of grid-connected power generation system

Info

Publication number: CN116454937B
Application number: CN202310688944.1A
Authority: CN
Inventors: 关东英; 鄢秋亮; 刘�东; 贺智威; 白宁; 杨晶
Original assignee: Sdic Candela Beijing New Energy Technology Co ltd
Current assignee: Sdic Candela Beijing New Energy Technology Co ltd
Priority date: 2023-06-12
Filing date: 2023-06-12
Publication date: 2024-01-09
Anticipated expiration: 2043-06-12
Also published as: CN116454937A

Abstract

The application discloses a control method, a control system, a control controller and a medium of a grid-connected power generation system, wherein the method is applied to the grid-connected power generation system and comprises the following steps: when the load power is lower than a first preset value, controlling the energy storage flywheel array of the first power generation subsystem to enter a preset power working state; when the load power is larger than the first preset value, controlling the energy storage flywheel array to increase power output, and when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, controlling the second power generation subsystem to output electric energy to the alternating current power grid. Therefore, on the basis that the first power generation subsystem adopts a full-power working state to carry out secondary power generation so as to output power to the alternating current power grid, the second power generation subsystem outputs power to the alternating current power grid to realize electric energy supplement, and therefore the power consumption requirement of the rear load can be met in the power consumption peak.

Description

Control method, system, controller and medium of grid-connected power generation system

Technical Field

The invention relates to the technical field of power grid regulation, in particular to a control method, a system, a controller and a medium of a grid-connected power generation system.

Background

The traditional power generation mode mainly comprises the step of burning fossil fuel in a thermal power plant to drive a gas turbine unit to generate power. With the increasing installed amount of new energy power generation, the installed amount of traditional fossil fuel power generation is continuously reduced. The existing new energy power generation system is provided with a flywheel energy storage system, however, the storage capacity of an energy storage flywheel in the flywheel energy storage system is limited, electric energy cannot be output in a large capacity for a long time, the energy cannot be used as effective electric energy to be supplemented in the event of electricity utilization peaks, and the electricity utilization requirement of a rear-end load cannot be met.

Disclosure of Invention

Based on the above, it is necessary to provide an inertia flywheel energy storage grid-connected control method and system, which aims at the technical problems that the storage capacity of an energy storage flywheel in the flywheel energy storage system of the current new energy power generation system is limited, electric energy cannot be output in a large capacity for a long time, the energy cannot be used as effective electric energy supplement in the event of power utilization peak, and the power utilization requirement of a rear end load cannot be met.

In a first aspect, the present application proposes a control method of a grid-connected power generation system, where the method is applied to the grid-connected power generation system, and the grid-connected power generation system includes: the system comprises a first power generation subsystem, a second power generation subsystem and a grid-connected switch, wherein the first power generation subsystem comprises a chemical battery array, an energy storage flywheel array, a motor inverter and a synchronous motor pair which are sequentially connected, the second power generation subsystem comprises a chemical battery array and a bidirectional converter which are sequentially connected, the chemical battery array is used for being connected with a power generation unit and taking power from the power generation unit, the synchronous motor pair is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch, and the bidirectional converter is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch;

The method comprises the following steps:

acquiring the current load power of the alternating current power grid;

when the load power is lower than a first preset value, controlling the energy storage flywheel array of the first power generation subsystem to enter a preset power working state;

when the load power is larger than the first preset value, controlling the energy storage flywheel array to increase power output, and when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, controlling the second power generation subsystem to output electric energy to the alternating current power grid.

In a second aspect, the present application proposes a grid-connected power generation system, including: the system comprises a system controller, a first power generation subsystem, a second power generation subsystem and a grid-connected switch, wherein the first power generation subsystem comprises a chemical battery array, an energy storage flywheel array, a motor inverter and a synchronous motor pair which are sequentially connected, the second power generation subsystem comprises a chemical battery array and a bidirectional converter which are sequentially connected, the chemical battery array is used for being connected with a power generation unit and taking power from the power generation unit, the synchronous motor pair is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch, and the bidirectional converter is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch; the system controller comprises a memory storing a computer program and a processor adapted to implement the steps of the control method of the grid-connected power generation system of any one of the first aspects when the computer program is executed.

In a third aspect, the present application proposes a computer readable storage medium storing a computer program, which when executed by a processor implements the steps of the control method of the grid-connected power generation system of any one of the first aspects.

In a fourth aspect, the present application proposes a system controller of a grid-connected power generation system, including a memory, and a processor, where the memory stores a computer program executable on the processor, and the processor implements the steps of the control method of the grid-connected power generation system according to any one of the first aspects when the processor executes the computer program.

Implementation of the embodiment of the application has the following beneficial effects:

(1) In the application, the chemical battery array is used for being connected with the power generation unit and taking power from the power generation unit, the energy storage flywheel array takes power from the chemical battery array, the chemical battery array has the advantage of long-time large-capacity energy storage requirement, the energy storage flywheel array has the advantage of short-time large-power output, and the long-time large-capacity output and short-time large-power output requirements are met through the cooperation of the chemical battery array and the energy storage flywheel array; when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, namely when the alternating current power grid is in a power utilization peak, the second power generation subsystem is controlled to output electric energy to the alternating current power grid, so that the electric energy supplement is realized by the output power of the second power generation subsystem to the alternating current power grid on the basis that the first power generation subsystem adopts the full-power working state to carry out secondary power generation to output power to the alternating current power grid, and the power utilization requirement of the rear-end load can be met when the alternating current power grid is in the power utilization peak.

(2) The inertia response to the alternating current power grid is realized through the synchronous motor pair of the first power generation subsystem, enough mechanical inertia supporting capacity is provided for the alternating current power grid, the impact of the load transient variation on the power grid side is avoided, and the stability of the power grid is improved.

(3) A large number of power electronic devices are used in the traditional new energy grid connection process, so that harmonic waves which harm a power grid are generated, particularly the harmonic wave content after high-proportion new energy grid connection is larger and larger, and the power grid is crashed when serious; meanwhile, the power electronic device in the grid-connected system can be directly damaged by the power grid fault, and the system can be destroyed and economic loss can be caused; according to the method, the synchronous motor is used for realizing secondary power generation grid connection, the influence of the harmonic waves of the power electronic device in the new energy station on the alternating current power grid can be isolated, the influence of the alternating current power grid fault on the internal power grid of the new energy station can be isolated, the stability of the power grid is improved, and the safety of the internal power grid of the new energy station is protected.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Wherein:

FIG. 1 is a schematic diagram of an application environment of a control method of a grid-connected power generation system in one embodiment;

FIG. 2 is a flow chart of a grid-tie of a control method of a grid-tie power generation system in one embodiment;

FIG. 3 is a flow chart of primary frequency modulation of a control method of a grid-connected power generation system in one embodiment;

FIG. 4 is a block diagram of a grid-tied power generation system in one embodiment;

fig. 5 is a block diagram of a system controller of the grid-connected power generation system in one embodiment.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order to better understand the control method, system, controller and medium of the grid-connected power generation system disclosed in the present application, an application environment of the control method of the grid-connected power generation system is first described, specifically, the control method of the grid-connected power generation system is used for controlling the grid-connected power generation system, and the grid-connected power generation system includes: the system comprises a first power generation subsystem, a second power generation subsystem and a grid-connected switch 010, wherein the first power generation subsystem comprises a chemical battery array 002, an energy storage flywheel array 003, a motor inverter 004 and a synchronous motor pair 005 which are sequentially connected, the second power generation subsystem comprises the chemical battery array 002 and a bidirectional converter 008 which are sequentially connected, the chemical battery array 002 is used for being connected with a power generation unit 001 and taking power from the power generation unit 001, the synchronous motor pair 005 is connected with the grid-connected switch 010 and can be connected with an alternating current power grid 007 through the grid-connected switch 010, and the bidirectional converter 008 is connected with the grid-connected switch 010 and can be connected with the alternating current power grid 007 through the grid-connected switch 010. A large number of power electronic devices are used in the traditional new energy grid connection process, so that harmonic waves which harm a power grid are generated, particularly the harmonic wave content after high-proportion new energy grid connection is larger and larger, and the power grid is crashed when serious; meanwhile, the power electronic device in the grid-connected system can be directly damaged by the power grid fault, and the system can be destroyed and economic loss can be caused; according to the method, the synchronous motor is used for realizing secondary power generation grid connection, the influence of the harmonic waves of the power electronic device in the new energy station on the alternating current power grid can be isolated, the influence of the alternating current power grid fault on the internal power grid of the new energy station can be isolated, the stability of the power grid is improved, and the safety of the internal power grid of the new energy station is protected.

The synchronous motor is used for carrying out secondary power generation grid connection on 005, and is mainly used for simulating a grid connection mode of a traditional thermal power generating unit, the synchronous motor can also provide a certain amount of mechanical inertia support for 005 under the condition that stable grid frequency electric energy can be provided, the mechanical inertia support can actively cope with frequency change of an alternating current grid, the function of the chemical battery array 002 is lacking in direct grid connection, therefore inertia response of the alternating current grid 007 is realized on 005 through the synchronous motor of a first power generation subsystem, enough mechanical inertia support capacity is provided for the alternating current grid 007, impact caused by load transient change on the side of the grid is avoided, and the stability of the grid is improved.

The power generation unit is a power station that generates electricity. Optionally, the power generation unit is a new energy power generation unit. For example, the power generation unit is a new energy station that generates power using new energy such as photovoltaic, wind power, and tide. The power generated by the power generation unit needs to be connected to an alternating current power grid. The grid-connected power generation system is used for connecting the power generated by the power generation unit to an alternating current power grid.

When the power generation unit is a new energy power generation unit, the power generation power of the power generation unit fluctuates, and the power generation unit is output according to needs after being stored by the chemical battery array 002, so that the fluctuation of the power generation power of the power generation unit is stabilized, and the chemical battery array 002 has the advantage of long-time large-capacity energy storage requirement, and can meet the storage requirement of the power generation unit. However, the chemical battery array 002 has the defect that short-time power output is difficult to achieve the maximum, so that in order to solve the problem, in the application, the chemical battery array 002 is adopted to convey electric energy to the energy storage flywheel array 003, the synchronous motor is driven by the energy storage flywheel array 003 to generate electricity for the second time and then is integrated into an alternating current power grid, the energy storage flywheel array 003 is high in charging and discharging times, high power can be output in a short time, the environment temperature is insensitive, the standby loss is low, and the system is safe and environment-friendly. That is, the grid-connected power generation system of the application is used for being connected with a power generation unit and taking power from the power generation unit through the chemical battery array, the energy storage flywheel array takes power from the chemical battery array, the chemical battery array has the advantage of long-time large-capacity energy storage requirement, the energy storage flywheel array has the advantage of being capable of outputting large power in a short time, and the long-time large-capacity output and the short-time large-power output are realized simultaneously through the cooperation of the chemical battery array and the energy storage flywheel array.

Alternatively, the number of chemical cell arrays 002 is one.

Optionally, the number of the chemical battery arrays 002 is two, both the two chemical battery arrays 002 are connected with the power generation unit 001 and take power from the power generation unit 001, the first chemical battery array 002 is connected with the energy storage flywheel array 003 to transmit electric energy to the energy storage flywheel array 003, and the second chemical battery array 002 is connected with the bidirectional converter 008 to transmit electric energy to the bidirectional converter 008.

The chemical battery array 002 includes a plurality of chemical battery cells therein. When the remaining energy proportion of the chemical battery unit is less than 20%, the chemical battery unit enters a charging state; when the remaining energy proportion of the chemical battery unit is more than 95%, the chemical battery unit enters an energy maintaining state or a discharging state; when the remaining energy ratio of the chemical battery cell is 20% or more and 95% or less, the chemical battery cell may be charged or discharged. Therefore, the over-discharge or over-charge risk of the chemical battery unit can be effectively reduced, a certain electric energy allowance is reserved to cope with the emergency, and the stability of the grid-connected power generation system is improved.

Optionally, the number of the grid-connected switches 010 is one.

Optionally, the number of the grid-connected switches 010 is two; a first end of a first grid-connected switch 010 is connected with the synchronous motor pair 005, and a second end of the first grid-connected switch 010 is connected with the alternating current power grid 007; a first end of a second grid-tie switch 010 is connected to the bi-directional converter 008 and a second end of the second grid-tie switch 010 is connected to the ac grid 007.

The pair 005 pair of synchronous motors comprises: the synchronous motor and the synchronous generator are connected in sequence, and the synchronous motor and the synchronous generator are coaxially and rigidly connected; the synchronous motor is connected with the motor inverter 004, the synchronous motor can drive the synchronous generator to synchronously rotate for generating power, and the synchronous generator is connected with the grid-connected switch 010 and can be connected with an alternating current power grid 007 through the grid-connected switch 010.

The working principle of the first power generation subsystem is as follows: the energy storage flywheel array 003 takes electricity from the chemical battery array 002 to charge, the energy storage flywheel array 003 outputs electric energy to the motor inverter 004, the motor inverter 004 converts direct current into alternating current to drive the synchronous motor to perform secondary power generation on 005, and the electric energy generated by the secondary power generation is integrated into the alternating current power grid 007 through the grid-connected switch 010.

The working principle of the second power generation subsystem is as follows: the electrical energy of the chemical battery array 002 is converted from direct current to alternating current by the bi-directional converter 008 and then enters the ac power grid 007. The second power generation subsystem is bi-directional and can deliver energy to or absorb energy from the ac power grid.

It can be understood that a system controller can be arranged in the grid-connected power generation system to load a program file for realizing the control method of the grid-connected power generation system, a switch control circuit can be arranged in the grid-connected power generation system to realize the method steps of the control method of the grid-connected power generation system, and a system can be arranged outside the grid-connected power generation system to load a program file for realizing the control method of the grid-connected power generation system.

The grid-connected power generation system is a power generation system and can be arranged in new energy stations such as photovoltaic, wind power and the like. The grid-connected power generation system can be used as a power generation side together with a traditional thermal power station or independently used as the power generation side to imitate the traditional thermal power station so as to supply power for a rear-end load. The grid-connected power generation system is a regulator of an alternating current power grid at the same time, for example, if the power generation power is not matched with the power consumption power of the alternating current power grid, the frequency of the alternating current power grid can rise or fall, and at the moment, the grid-connected power generation system can be controlled to have less output mechanical power and less power generation or more output mechanical power and more power generation so as to realize the regulation of the frequency of the alternating current power grid; of course, the synchronous generator of the grid-connected power generation system can also be used as a regulator of reactive power.

The power generation unit 001, the grid-connected switch 010, the chemical battery array 002, the energy storage flywheel array 003, the motor inverter 004, the bidirectional converter 008 and the synchronous motor pair 005 and the like are only schematically shown, and specific structures, sizes, shapes, positions, mounting modes and the like can be adaptively adjusted according to actual requirements, so that the method is not limited.

The application environment used by the control method of the grid-connected power generation system is described above, and the control method, the system, the controller and the medium of the grid-connected power generation system are described in detail below.

As shown in fig. 2, in one embodiment, there is provided a control method of a grid-connected power generation system, the method being applied to the grid-connected power generation system, wherein the grid-connected power generation system includes: the system comprises a first power generation subsystem, a second power generation subsystem and a grid-connected switch, wherein the first power generation subsystem comprises a chemical battery array, an energy storage flywheel array, a motor inverter and a synchronous motor pair which are sequentially connected, the second power generation subsystem comprises a chemical battery array and a bidirectional converter which are sequentially connected, the chemical battery array is used for being connected with a power generation unit and taking power from the power generation unit, the synchronous motor pair is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch, and the bidirectional converter is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch;

The method comprises the following steps:

s1: acquiring the current load power of the alternating current power grid;

the current load power of the alternating current power grid is the power of the real-time load of the alternating current power grid.

Specifically, the current load power of the ac power grid detected by the detecting device may be obtained, and the current load power of the ac power grid sent by the third party application may also be obtained.

S2: when the load power is lower than a first preset value, controlling the energy storage flywheel array of the first power generation subsystem to enter a preset power working state;

specifically, when the load power is lower than a first preset value, the condition that the alternating current power grid is low in power consumption and low in electric energy demand is indicated, and the energy storage flywheel array of the first power generation subsystem is controlled to enter a preset power working state, so that the frequency of the synchronous motor pair is maintained under the condition that the synchronous motor pair operates at the power grid frequency with low power and the low-power electric energy can be output to the alternating current power grid, and accidents caused by the fact that the synchronous motor pair needs to be started in emergency state are avoided.

S3: when the load power is larger than the first preset value, controlling the energy storage flywheel array to increase power output, and when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, controlling the second power generation subsystem to output electric energy to the alternating current power grid.

Specifically, when the load power is greater than the first preset value, the alternating current power grid is developed towards a peak of electricity consumption, the demand for electric energy is high, and the energy storage flywheel array is controlled to increase the power output so as to increase the generated power of the synchronous motor pair, so that the demand for electric energy of the alternating current power grid is increased; when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, the energy storage flywheel array means that a power utilization peak is entered, the limit of the power input by the first power generation subsystem to the alternating current power grid is exceeded, but the power output requirement corresponding to the load power is still not met, so that the second power generation subsystem is controlled to output electric energy to the alternating current power grid, and the power output to the alternating current power grid is expanded through the second power generation subsystem on the basis of the first power generation subsystem.

It can be understood that when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, the energy storage flywheel array does not retain the energy retention state any more, and all the energy storage flywheel units in the energy storage flywheel array enter a charge-discharge circulation state, and at this time, the energy storage flywheel units meeting the discharge requirement can be discharged.

The technical effects achieved by the embodiment are as follows: (1) In the application, the chemical battery array is used for being connected with the power generation unit and taking power from the power generation unit, the energy storage flywheel array takes power from the chemical battery array, the chemical battery array has the advantage of long-time large-capacity energy storage requirement, the energy storage flywheel array has the advantage of short-time large-power output, and the long-time large-capacity output and short-time large-power output requirements are met through the cooperation of the chemical battery array and the energy storage flywheel array; when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, namely when the alternating current power grid is in a power utilization peak, the second power generation subsystem is controlled to output electric energy to the alternating current power grid, so that the electric energy supplement is realized by the output power of the second power generation subsystem to the alternating current power grid on the basis that the first power generation subsystem adopts the full-power working state to carry out secondary power generation to output power to the alternating current power grid, and the power utilization requirement of the rear-end load can be met when the alternating current power grid is in the power utilization peak. (2) The inertia response to the alternating current power grid is realized through the synchronous motor pair of the first power generation subsystem, enough mechanical inertia supporting capacity is provided for the alternating current power grid, the impact of the load transient variation on the power grid side is avoided, and the stability of the power grid is improved. (3) A large number of power electronic devices are used in the traditional new energy grid connection process, so that harmonic waves which harm a power grid are generated, particularly the harmonic wave content after high-proportion new energy grid connection is larger and larger, and the power grid is crashed when serious; meanwhile, the power electronic device in the grid-connected system can be directly damaged by the power grid fault, and the system can be destroyed and economic loss can be caused; according to the method, the synchronous motor is used for realizing secondary power generation grid connection, the influence of the harmonic waves of the power electronic device in the new energy station on the alternating current power grid can be isolated, the influence of the alternating current power grid fault on the internal power grid of the new energy station can be isolated, the stability of the power grid is improved, and the safety of the internal power grid of the new energy station is protected.

As shown in fig. 3, in one embodiment, the grid-connected power generation system further includes: the detection device is used for detecting the grid instantaneous frequency of the alternating current grid;

specifically, the detection device includes: the frequency detection sensor is used for detecting the frequency of the alternating current power grid in real time, for example, detecting one end of the grid-connected switch connected with the alternating current power grid in real time, so as to detect the instantaneous frequency of the alternating current power grid. The frequency detection sensor is a sensor for detecting the frequency of the ac power grid. It is understood that the frequency of the ac power grid detected by the frequency detection sensor is taken as the grid instantaneous frequency.

The method further comprises the steps of:

s41: acquiring a frequency deviation value between the instantaneous frequency of the power grid and a preset rated frequency of the power grid;

the power grid instantaneous frequency is the alternating current power supply frequency of the alternating current power grid detected in real time.

The preset rated frequency of the power grid is the rated alternating current power supply frequency of the alternating current power grid. Optionally, the preset rated frequency of the power grid is 50HZ.

Specifically, the power grid instantaneous frequency of the alternating current power grid sent by the detection device is obtained, the latest obtained power grid instantaneous frequency is subtracted by the preset power grid rated frequency, and the subtracted data are used as frequency deviation values.

S42: when the frequency deviation value is positive and larger than a preset positive dead zone frequency or the frequency deviation value is negative and smaller than a preset negative dead zone frequency, calculating a power compensation value for primary frequency modulation according to the frequency deviation value;

frequency modulation is divided into two phases: a phase of inertia response and a phase of primary frequency modulation. The phase of inertia response wins time for the phase of primary frequency modulation. The phase of the inertia response is the frequency modulation of the passive response. The primary frequency modulation stage is actively performed frequency modulation.

When the frequency deviation value is outside the dead zone frequency range, the primary frequency modulation stage is required to be entered, wherein the dead zone frequency range is a range from a preset negative dead zone frequency to a preset positive dead zone frequency. When the frequency deviation value is within the dead band frequency range, no primary frequency modulation stage is required.

Optionally, the preset forward dead band frequency is 0.05HZ. It will be appreciated that the predetermined forward dead band frequency may be other values, such as, but not limited to, a value between 0.025HZ and 0.055 HZ.

Optionally, the preset negative dead band frequency is-0.05 HZ. It will be appreciated that the predetermined negative dead band frequency may be other values, such as, but not limited to, values between-0.055 HZ and-0.025 HZ.

Specifically, when the frequency deviation value is positive and is greater than the preset forward dead zone frequency, it means that primary frequency modulation is needed, and because the frequency deviation value is positive, it indicates that the active power of the ac power grid is excessive, that is, the load of the ac power grid is insufficient, at this time, if the synchronous motor maintains the original mechanical power output, the rotation speed of the rotor system composed of the synchronous motor and the synchronous generator will continue to rise, and in order to inhibit the frequency of the ac power grid from continuously increasing, the power output to the ac power grid needs to be reduced through primary frequency modulation; when the frequency deviation value is negative and smaller than the preset negative dead zone frequency, the primary frequency modulation is needed, and the active power shortage of the alternating current power grid is indicated because the frequency deviation value is negative, that is, the load of the alternating current power grid is excessive, at the moment, if the synchronous motor maintains the original mechanical power output, the rotating speed of a rotor system formed by the synchronous motor and the synchronous generator can be further reduced, and in order to inhibit the frequency of the alternating current power grid from further reducing, the power output to the alternating current power grid needs to be increased through the primary frequency modulation. Therefore, when the frequency deviation value is positive and greater than a preset positive dead frequency, or when the frequency deviation value is negative and less than a preset negative dead frequency, a primary frequency modulation is required.

The calculation method for calculating the power compensation value for primary frequency modulation according to the frequency deviation value may be selected from the prior art, and will not be described herein.

S43: when the absolute value of the power compensation value is larger than the reserved power generation power of the synchronous motor pair, controlling the first power generation subsystem and the second power generation subsystem to work simultaneously for primary frequency modulation;

the synchronous motor pair reserves generated power for coping with power fluctuation of the alternating current network at the network side when designing. The reserved generated power of the synchronous motor pair comprises the following components: a first power and a second power; the first power is a reserve value of rated power of the synchronous motor, and the second power is a reserve value of rated power of the synchronous generator.

Optionally, the first power is 10% of the rated power of the synchronous motor, and the second power is 10% of the rated power of the synchronous generator. It is understood that the first power and the second power may be other values, which are not limited herein.

Specifically, when the absolute value of the power compensation value is greater than the reserved generated power of the synchronous motor pair, this means that the first power generation subsystem alone cannot meet the requirement of primary frequency modulation, and the second power generation subsystem needs to be started as a supplement to primary frequency modulation, so that the first power generation subsystem and the second power generation subsystem are controlled to work simultaneously to perform primary frequency modulation.

S44: and when the power compensation value is smaller than or equal to the reserved generated power of the synchronous motor pair, controlling the first power generation subsystem to work for primary frequency modulation.

Specifically, when the power compensation value is smaller than or equal to the reserved generated power of the synchronous motor pair, this means that the first power generation subsystem alone can meet the requirement of primary frequency modulation, and therefore the first power generation subsystem is controlled to work for primary frequency modulation.

According to the embodiment, when the power compensation value is smaller than or equal to the reserved power generation power of the synchronous motor pair, the first power generation subsystem is controlled to work for primary frequency modulation, the primary frequency modulation is carried out by adopting the first power generation subsystem independently, and when the absolute value of the power compensation value is larger than the reserved power generation power of the synchronous motor pair, the first power generation subsystem and the second power generation subsystem are controlled to work for primary frequency modulation simultaneously, and on the basis of taking the first power generation subsystem as a primary frequency modulation main system, the primary frequency modulation method is suitable for primary frequency modulation in the combination range of the reserved power generation power and the power of the second power generation subsystem, the application range of primary frequency modulation is improved, and the efficiency of independently supporting the frequency stability of an alternating current power grid is also improved.

In one embodiment, the step of controlling the first power generation subsystem and the second power generation subsystem to operate simultaneously for primary frequency modulation includes:

s431: when the frequency deviation value is positive and larger than a preset forward dead zone frequency, controlling the energy storage flywheel array to reduce power output, and controlling the second power generation subsystem to absorb active power from the alternating current power grid;

specifically, when the frequency deviation value is positive and is greater than the preset forward dead frequency, this means that primary frequency modulation is needed, and because the frequency deviation value is positive, this indicates that the active power of the ac power grid is excessive, that is, the load of the ac power grid is insufficient, at this time, if the synchronous motor maintains the original mechanical power output, the rotation speed of the rotor system formed by the synchronous motor and the synchronous generator will continue to rise, in order to inhibit the frequency of the ac power grid from continuously increasing, the power output to the ac power grid needs to be reduced through primary frequency modulation, so that the energy storage flywheel array is controlled to reduce the power output, and the second power generation subsystem is controlled to absorb the active power from the ac power grid, and the primary frequency modulation is realized through the simultaneous operation of the first power generation subsystem and the second power generation subsystem.

Optionally, controlling the energy storage flywheel array to reduce power output according to the reserved generated power; and controlling the second power generation subsystem to absorb active power from the alternating current power grid according to a difference value obtained by subtracting the reserved power generation power from the absolute value of the power compensation value. Thereby minimizing the active power drawn by the second power generation subsystem from the ac power grid.

Optionally, controlling the energy storage flywheel array to reduce power output according to a value smaller than the reserved generated power; and subtracting the reserved generated power from the absolute value of the power compensation value to obtain a difference value, and controlling the second power generation subsystem to absorb active power from the alternating current power grid according to a value larger than the difference value. Thereby shortening the time required for primary frequency modulation.

S432: and when the frequency deviation value is negative and smaller than a preset negative dead frequency, controlling the energy storage flywheel array to increase power output, and controlling the second power generation subsystem to output active power to the alternating current power grid.

Specifically, when the frequency deviation value is negative and is smaller than the preset negative dead frequency, this means that primary frequency modulation is needed, and because the frequency deviation value is negative, the active power shortage of the ac power grid is indicated, that is, the load of the ac power grid is excessive, at this time, if the synchronous motor maintains the original mechanical power output, the rotation speed of the rotor system composed of the synchronous motor and the synchronous generator will further decrease, and in order to inhibit the frequency of the ac power grid from further decreasing, the power output to the ac power grid needs to be increased through primary frequency modulation. Therefore, when the frequency deviation value is positive and greater than a preset positive dead zone frequency, or when the frequency deviation value is negative and less than a preset negative dead zone frequency, primary frequency modulation is needed, so that the energy storage flywheel array is controlled to increase power output, the second power generation subsystem is controlled to output active power to the alternating current power grid, and the primary frequency modulation is realized by the simultaneous operation of the first power generation subsystem and the second power generation subsystem.

Optionally, controlling the energy storage flywheel array to increase power output according to the reserved power generation power; and controlling the second power generation subsystem to output active power to the alternating current power grid according to a difference value obtained by subtracting the reserved power generation power from the absolute value of the power compensation value. Thereby realizing the reduction of the power output by the second power generation subsystem to the alternating current power grid as much as possible.

Optionally, controlling the energy storage flywheel array to increase power output according to a value smaller than the reserved power; and subtracting the reserved generated power from the absolute value of the power compensation value to obtain a difference value, and controlling the second power generation subsystem to output active power to the alternating current power grid according to the value larger than the difference value. Thereby shortening the time required for primary frequency modulation.

According to the embodiment, the first power generation subsystem and the second power generation subsystem are controlled to work simultaneously to perform primary frequency modulation, and on the basis of taking the first power generation subsystem as a primary frequency modulation main system, the primary frequency modulation method is applicable to primary frequency modulation in a reserved combination range of power generation power and power of the second power generation subsystem, the application range of primary frequency modulation is improved, and the efficiency of independently supporting the frequency stability of an alternating current power grid is also improved.

In one embodiment, the detection device is further configured to detect first remaining energy data corresponding to the chemical battery array and second remaining energy data corresponding to the energy storage flywheel array;

specifically, the detection device includes: the first residual energy detection sensor is connected with the chemical battery array to acquire residual energy data corresponding to the chemical battery array, the residual energy data is used as first residual energy data, and the second residual energy detection sensor is connected with the energy storage flywheel array to acquire residual energy data corresponding to the energy storage flywheel array, and the residual energy data is used as second residual energy data.

The first remaining energy data may be percentage data or may be specific circuit values. The second remaining energy data may be percentage data or may be specific circuit values.

The method further comprises the steps of:

s51: acquiring the power generated by the power generation unit;

specifically, a detection system of a power generation unit detects the power generated by the power generation unit; thus, the generated power of the power generation unit is obtained from the detection system.

S52: when the generated power is larger than a second preset value, judging whether the first residual energy data is larger than a preset first threshold value or not;

Specifically, when the generated power is greater than the second preset value, this means that the power generation unit enters a power generation peak.

Optionally, the preset first threshold is set to 95%. It is understood that the preset first threshold may be set to other values, which are not limited herein.

S53: if so, judging whether the second residual energy data is larger than a preset second threshold value or not;

specifically, if the first remaining energy data is greater than a preset first threshold, it means that the energy of the chemical battery array has reached the maximum energy storage requirement of the chemical battery array, and the chemical battery array needs to enter an energy holding or discharging state to avoid overcharging.

It is understood that when the first remaining energy data is less than or equal to a preset first threshold, this means that the energy of the chemical battery array does not reach the maximum energy storage requirement of the chemical battery array, and the chemical battery array may continue to charge.

Optionally, the preset second threshold is set to 98%. It is understood that the preset second threshold may be set to other values, which are not limited herein.

S54: when the second residual energy data is larger than the second threshold value, sending a signal for stopping power transmission to the power generation unit or controlling the chemical battery array to release electric energy to target load equipment;

Specifically, when the second remaining energy data is greater than the second threshold, it means that the energy of the energy storage flywheel array has reached the maximum energy storage requirement of the energy storage flywheel array, and the energy storage flywheel array cannot continue to be charged, so that a power transmission stop signal is sent to the power generation unit to stop the power generation unit from transmitting power to the chemical battery array, or the chemical battery array is controlled to release power to a target load device to avoid overcharging of the energy storage flywheel array.

S55: and when the second residual energy data is smaller than or equal to the second threshold value, controlling the chemical battery array to release electric energy to the energy storage flywheel array according to the generated energy of the power generation unit.

Specifically, when the second remaining energy data is smaller than or equal to the second threshold, it means that the energy of the energy storage flywheel array does not reach the maximum energy storage requirement of the energy storage flywheel array, and the energy storage flywheel array can continue to be charged, so that the chemical battery array is controlled to actively release electric energy to the energy storage flywheel array according to the generated energy of the power generation unit, that is, the speed of charging the chemical battery array by the power generation unit is equal to the speed of actively releasing electric energy to the energy storage flywheel array by the chemical battery array, and the chemical battery array is equal to an electric energy transfer station.

In this embodiment, when the energy of the chemical battery array has reached the maximum energy storage requirement of the chemical battery array, and the energy of the energy storage flywheel array has reached the maximum energy storage requirement of the energy storage flywheel array, a power transmission stopping signal is sent to the power generation unit or the chemical battery array is controlled to release electric energy to a target load device, so that overcharging of the energy storage flywheel array and the chemical battery array is avoided; when the energy of the chemical battery array reaches the maximum energy storage requirement of the chemical battery array, and the energy of the energy storage flywheel array does not reach the maximum energy storage requirement of the energy storage flywheel array, the chemical battery array is controlled to release electric energy to the energy storage flywheel array according to the generated energy of the power generation unit, so that the overcharge of the chemical battery array is avoided, and the electric energy generated by the power generation unit is also prevented from being wasted.

In one embodiment, after the step of obtaining the generated power of the power generation unit, the method further includes:

s561: when the generated power is smaller than a third preset value, summing the residual energy value corresponding to the chemical battery array and the residual energy value corresponding to the energy storage flywheel array to obtain a total residual energy value;

Specifically, when the generated power is smaller than the third preset value, it means that the generating unit enters a low generating valley, and the first power generation subsystem is considered to be prevented from being stopped at this time, so that the residual energy value corresponding to the chemical battery array and the residual energy value corresponding to the energy storage flywheel array are summed, and the obtained data is taken as a total residual energy value.

S562: when the total value of the residual energy is smaller than the minimum required value of the system energy corresponding to the grid-connected power generation system, controlling the second power generation subsystem to absorb electricity from the alternating current power grid, and controlling the first power generation subsystem to enter a standby operation mode;

optionally, the minimum required value of the system energy corresponding to the grid-connected power generation system is the minimum energy required for keeping the first power generation subsystem not shut down. When the total value of the residual energy is smaller than the minimum required value of the system energy corresponding to the grid-connected power generation system, the energy in the chemical battery array and the energy storage flywheel array cannot ensure that the first power generation subsystem is not stopped, so that the second power generation subsystem is controlled to absorb power from the alternating current power grid, and at the moment, the bidirectional converter converts the alternating current absorbed from the alternating current power grid into direct current and repeats the direct current into the chemical battery array so as to be used for supplementing the energy of the chemical battery array; and controlling the first power generation subsystem to enter a standby operation mode so as to keep the second power generation subsystem in a non-stop state.

Optionally, the minimum required value of the system energy corresponding to the grid-connected power generation system is the minimum energy required for keeping the grid-connected power generation system not shut down. The system energy corresponding to the grid-connected power generation system is the sum of the minimum energy required by the first power generation subsystem without stopping, the minimum protection electric quantity of the chemical battery array and the minimum protection electric quantity of the energy storage flywheel array. The minimum protection power of the chemical battery array is the minimum power required for protecting the batteries in the chemical battery array, and the chemical battery array cannot provide electric energy outwards when the minimum protection power of the chemical battery array is lower than the minimum protection power of the chemical battery array. The minimum protection electric quantity of the energy storage flywheel array is the minimum electric quantity required by protecting a battery in the energy storage flywheel array, and the energy storage flywheel array cannot provide electric energy outwards when the minimum protection electric quantity of the energy storage flywheel array is lower than the minimum protection electric quantity of the energy storage flywheel array.

S563: and when the total value of the residual energy is greater than or equal to the minimum required value of the system energy, controlling the first power generation subsystem to enter a low-power output mode.

In particular, when the total value of the remaining energy is greater than or equal to the minimum required value of the system energy, this means that the energy in the chemical battery array and the energy storage flywheel array at least ensures that the first power generation subsystem is not shut down, and therefore, the first power generation subsystem is controlled to enter a low power output mode for outputting low power electrical energy to the ac grid.

In this embodiment, when the total value of the remaining energy is smaller than the minimum required value of the system energy corresponding to the grid-connected power generation system, the second power generation subsystem is controlled to absorb power from the ac power grid, and the first power generation subsystem is controlled to enter a standby operation mode, so that the first power generation subsystem is prevented from being stopped, the synchronous motor pair of the first power generation subsystem is maintained to operate at the power grid frequency with low power, the frequency of the synchronous motor pair is maintained under the condition that low-power electric energy can be output to the ac power grid, and accidents caused by the need of starting time of the synchronous motor pair when an emergency state occurs are avoided; and when the total value of the residual energy is larger than or equal to the minimum required value of the system energy, controlling the first power generation subsystem to enter a low-power output mode for outputting low-power electric energy to an alternating current power grid.

s562: when the generated power is smaller than a third preset value, acquiring the frequency deviation value between the instantaneous frequency of the power grid and the preset rated frequency of the power grid;

specifically, when the generated power is smaller than a third preset value, the generation unit enters a low power generation valley, and when the grid side load of the alternating current grid needs to be considered to be slowly increased, the frequency of the alternating current grid is adjusted; thus, the frequency deviation value between the grid instantaneous frequency and a preset grid rated frequency is obtained.

S563: when the frequency deviation value is negative, obtaining a frequency change rate corresponding to the instantaneous frequency of the power grid;

specifically, when the frequency deviation value is negative, the active power shortage of the ac power grid is indicated, and the grid side load of the ac power grid is increasing, so that the frequency change rate corresponding to the grid instantaneous frequency with the latest detection time is obtained.

S564: and when the frequency change rate is in a preset slow increasing range, controlling the energy storage flywheel array to increase power output.

Specifically, when the frequency change rate is within a preset slow increase range, which means that the load on the grid side of the ac grid is slowly increased, the energy storage flywheel array needs to be controlled to increase the power output so as to reduce the frequency of the ac grid.

It is understood that primary frequency modulation is the adjustment of the frequency of the ac grid when the grid side load of the ac grid is rapidly changing, whereas the present application is the adjustment of the frequency of the ac grid when the grid side load of the ac grid is slowly increasing.

According to the embodiment, when the frequency change rate is in the preset slow increasing range, the energy storage flywheel array is controlled to increase the power output, so that the frequency of the alternating current power grid can be adjusted when the load on the power grid side of the alternating current power grid is slowly increased, and the capacity of supporting the frequency stability of the alternating current power grid is improved.

In one embodiment, the method further comprises:

s61: acquiring a system starting instruction;

the system starting instruction is an instruction for starting or restarting the grid-connected power generation system for the first time.

Specifically, the system start instruction input by the user may be a system start instruction sent by the third party application system.

S62: responding to the system starting instruction, controlling the chemical battery array to take electricity from the power generation unit so as to realize energy storage of the chemical battery array, and controlling the energy storage flywheel array to take electricity from the chemical battery array so as to realize energy storage of the energy storage flywheel array when the first residual energy data is larger than a preset third threshold value;

specifically, when the system start command is received, the grid-connected power generation system needs to be started for the first time or restarted, the chemical battery array is controlled to take electricity from the power generation unit to realize energy storage of the chemical battery array, and when the first residual energy data is larger than a preset third threshold value, the chemical battery array only reaches a discharge standard corresponding to the chemical battery array when the grid-connected power generation system is started, so that the energy storage flywheel array is controlled to take electricity from the chemical battery array to realize energy storage of the energy storage flywheel array.

Optionally, the preset third threshold is 50%. It is understood that the preset third threshold may also be other values, which are not limited herein.

It can be understood that, in response to the system start command, the chemical battery array is controlled to draw electricity from the power generation unit to achieve energy storage of the chemical battery array, and when the first residual energy data is less than or equal to a preset third threshold value, the chemical battery array is controlled to draw electricity from the power generation unit to achieve continuous energy storage of the chemical battery array until the first residual energy data is greater than the preset third threshold value.

S63: and when the second residual energy data is larger than a preset fourth threshold value, controlling the grid-connected switch to be closed so as to realize grid connection through the first power generation subsystem.

Optionally, the preset fourth threshold is 50%. It will be appreciated that the fourth threshold may be other values, not limited herein.

Specifically, when the second residual energy data is greater than a preset fourth threshold, the energy storage flywheel array only reaches a discharge standard corresponding to the energy storage flywheel array when the grid-connected power generation system is started, so that the grid-connected switch can be controlled to be closed to realize grid connection through the first power generation subsystem.

It is understood that when the second remaining energy data is less than or equal to a preset fourth threshold, the energy storage flywheel array is controlled to draw electricity from the chemical battery array to achieve continuous energy storage of the energy storage flywheel array until the second remaining energy data is greater than the preset fourth threshold.

When the grid-connected power generation system is started, energy is firstly stored in the chemical battery array, when the first residual energy data of the chemical battery array is larger than a preset third threshold value, electricity is taken from the chemical battery array to store the energy of the energy storage flywheel array, and when the second residual energy data of the energy storage flywheel array is larger than a preset fourth threshold value, the grid-connected switch is controlled to be closed so as to realize grid connection through the first power generation subsystem, so that instant drop of the residual energy data of the chemical battery array and/or the energy storage flywheel array when the grid-connected switch is closed is avoided, overdischarge of the chemical battery array and/or the energy storage flywheel array is avoided, the service lives of the chemical battery array and the energy storage flywheel array are protected, and shutdown of the synchronous motor pair caused by incapacity of maintaining operation of the synchronous motor pair is also avoided; the frequency fluctuation of the connection point (also called a grid connection point) between the grid-connected power generation system and the alternating current power grid caused by the shutdown of the synchronous motor is particularly large, and the stability of the alternating current power grid is affected.

In one embodiment, the pair of synchronous motors includes: the synchronous motor and the synchronous generator are coaxially and rigidly connected; the synchronous motor is connected with the motor inverter, the synchronous motor can drive the synchronous generator to synchronously rotate for generating power, and the synchronous generator is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch;

when the frequency deviation value is not equal to 0, the synchronous motor and the synchronous generator realize inertia response to the alternating current power grid.

Specifically, when the frequency deviation value is not equal to 0, it means that the instantaneous frequency of the ac power grid at this time does not meet the preset requirement (preset rated frequency of the power grid), frequency modulation is required for the ac power grid, and at this time, inertia response to the ac power grid is realized through the synchronous motor, the synchronous generator and the inertia flywheel, so that the frequency change rate is delayed, and rapid frequency drop is prevented, so that when the frequency deviation value is not equal to 0, the synchronous motor and the synchronous generator realize inertia response to the ac power grid.

The rotor of the synchronous motor and the rotor of the synchronous generator form a rotor system, and inertia support is provided through the rotational inertia of the rotor system so as to realize inertia response to the alternating current power grid. The inertial support is a short-time impact type power support.

According to the embodiment, inertia response to the alternating current power grid is achieved through the synchronous motor and the synchronous generator, enough mechanical inertia supporting capacity is provided for the alternating current power grid, impact caused by instantaneous load change at the power grid side is avoided, and stability of the power grid is improved.

In one embodiment, the first power generation subsystem further includes a first parallel-network transformer, an input end of the first parallel-network transformer is connected to the pair of synchronous motors, and an output end of the first parallel-network transformer is connected to the grid-connected switch and can be connected to the ac power grid through the grid-connected switch; and/or the number of the groups of groups,

the second power generation subsystem further comprises a second grid-connected transformer, the input end of the second grid-connected transformer is connected with the bidirectional converter, and the output end of the second grid-connected transformer is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch.

And the first parallel network transformer is used for transforming the electric energy input into the first parallel network transformer and then merging the electric energy into the alternating current power grid. And the second grid-connected transformer is used for transforming the electric energy input into the second grid-connected transformer and then merging the electric energy into the alternating current power grid. The first parallel-network transformer and the second parallel-network transformer are both grid-connected transformers.

In an optional implementation manner of this embodiment, the first power generation subsystem further includes a first parallel-network transformer, an input end of the first parallel-network transformer is connected to the pair of synchronous motors, and an output end of the first parallel-network transformer is connected to the grid-connected switch and can be connected to the ac power grid through the grid-connected switch: the second power generation subsystem further comprises a second grid-connected transformer, the input end of the second grid-connected transformer is connected with the bidirectional converter, and the output end of the second grid-connected transformer is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch.

In an optional implementation manner of this embodiment, the first power generation subsystem further includes a first parallel-network transformer, an input end of the first parallel-network transformer is connected to the pair of synchronous motors, and an output end of the first parallel-network transformer is connected to the grid-connected switch and can be connected to the ac power grid through the grid-connected switch.

In an optional implementation manner of this embodiment, the second power generation subsystem further includes a second grid-connected transformer, an input end of the second grid-connected transformer is connected to the bidirectional converter, and an output end of the second grid-connected transformer is connected to the grid-connected switch and can be connected to the ac power grid through the grid-connected switch.

It will be appreciated that in this embodiment, the synchronous motor pair is not directly connected to the grid-tie switch, and the bidirectional converter is not directly connected to the grid-tie switch.

According to the embodiment, the first grid-connected transformer is arranged for the first power generation subsystem and/or the second grid-connected transformer is arranged for the second power generation subsystem, so that the voltage of electric energy is adjusted before grid connection, the grid-connected stability of the grid-connected power generation system is improved, and the adaptability of the grid-connected power generation system is improved.

In one embodiment, the energy storing flywheel array comprises: the system comprises a plurality of energy storage flywheel units, a plurality of bidirectional energy storage converters and an energy storage flywheel array controller, wherein the energy storage flywheel units are in one-to-one correspondence with the bidirectional energy storage converters, and the energy storage flywheel array controller is connected with each bidirectional energy storage converter; the chemical battery array charges the energy storage flywheel unit through the bidirectional energy storage converter, and the energy storage flywheel unit provides electric energy for the motor inverter through the bidirectional energy storage converter.

The energy storage flywheel unit includes: and an energy storage flywheel.

Optionally, when the remaining energy proportion in the energy storage flywheel unit is less than 30%, the energy storage flywheel unit enters a charging state to maintain the energy storage flywheel unit in a constant power state, and stabilize the total power output of the energy storage flywheel array; when the remaining energy proportion in the energy storage flywheel unit is greater than 98%, the energy storage flywheel unit enters an energy holding state or a discharging state, so that the energy of the energy storage flywheel unit can be discharged in a short time, and meanwhile, the phenomenon that the energy storage flywheel unit is overcharged and the endurance life is reduced is avoided; the energy storage flywheel unit may be charged or discharged when the remaining energy in the energy storage flywheel unit is greater than or equal to 30% and less than or equal to 98%.

In order to solve the problem, the chemical battery array is used for conveying electric energy to the energy storage flywheel array, the energy storage flywheel array drives the synchronous motor to perform secondary power generation and then is integrated into an alternating current power grid, the energy storage flywheel array has the advantages of being high in charge and discharge times, capable of outputting high power in a short time, insensitive to environmental temperature, low in standby loss and safe and environment-friendly. Through the cooperation of the energy storage flywheel array and the chemical battery array, the long-time high-capacity and short-time high-power output is realized.

In one embodiment, the power generation unit is a new energy power station.

The new energy power station is a unit for new energy power generation.

A large number of power electronic devices are used in the traditional new energy grid connection process, so that harmonic waves which harm a power grid are generated, particularly the harmonic wave content after high-proportion new energy grid connection is larger and larger, and the power grid is crashed when serious; meanwhile, the power electronic device in the grid-connected system can be directly damaged by the power grid fault, and the system can be destroyed and economic loss can be caused; according to the method, the synchronous motor is used for realizing secondary power generation grid connection, the influence of the harmonic waves of the power electronic device in the new energy station on the alternating current power grid can be isolated, the influence of the alternating current power grid fault on the internal power grid of the new energy station can be isolated, the stability of the power grid is improved, and the safety of the internal power grid of the new energy station is protected.

In one embodiment, the chemical battery array is a lithium battery array, and the first power generation subsystem and the second power generation subsystem share the same lithium battery array.

In this embodiment, the first power generation subsystem and the second power generation subsystem share the same lithium battery array, so that control steps of the grid-connected power generation system are simplified.

As shown in fig. 4, in one embodiment, there is provided a grid-connected power generation system including: the system comprises a system controller, a first power generation subsystem, a second power generation subsystem and a grid-connected switch 010, wherein the first power generation subsystem comprises a chemical battery array 002, an energy storage flywheel array 003, a motor inverter 004 and a synchronous motor pair 005 which are sequentially connected, the second power generation subsystem comprises the chemical battery array 002 and a bidirectional converter 008 which are sequentially connected, the chemical battery array 002 is used for being connected with a power generation unit 001 and taking power from the power generation unit 001, the synchronous motor pair 005 is connected with the grid-connected switch 010 and can be connected with an alternating current power grid 007 through the grid-connected switch 010, and the bidirectional converter 008 is connected with the grid-connected switch 010 and can be connected with the alternating current power grid 007 through the grid-connected switch 010; the system controller comprises a memory storing a computer program and a processor adapted to implement the steps of the control method of the grid-connected power generation system of any one of the above, when the computer program is executed.

The grid-connected power generation system further includes: a detection device (not shown) for detecting the grid instantaneous frequency of the ac grid 007.

The detection device is further configured to detect first remaining energy data corresponding to the chemical battery array 002 and second remaining energy data corresponding to the energy storage flywheel array 003.

The pair of synchronous motors 005 includes: the synchronous motor and the synchronous generator are coaxially and rigidly connected; the synchronous motor is connected with the motor inverter 004, the synchronous motor can drive the synchronous generator to synchronously rotate for generating power, and the synchronous generator is connected with the grid-connected switch 010 and can be connected with an alternating current power grid 007 through the grid-connected switch 010.

In one embodiment, the first power generation subsystem further includes a first shunt transformer 006, an input terminal of the first shunt transformer 006 is connected to the pair of synchronous motors 005, and an output terminal of the first shunt transformer 006 is connected to the grid-connected switch 010 and can be connected to the ac power grid 007 through the grid-connected switch 010; and/or the number of the groups of groups,

the second power generation subsystem further comprises a second grid-connected transformer 009, an input end of the second grid-connected transformer 009 is connected with the bidirectional converter 008, and an output end of the second grid-connected transformer 009 is connected with the grid-connected switch 010 and can be connected with the alternating current power grid 007 through the grid-connected switch 010.

The energy storage flywheel array 003 includes: the system comprises a plurality of energy storage flywheel units, a plurality of bidirectional energy storage converters and an energy storage flywheel array controller, wherein the energy storage flywheel units are in one-to-one correspondence with the bidirectional energy storage converters, and the energy storage flywheel array controller is connected with each bidirectional energy storage converter; the chemical battery array 002 charges the energy storage flywheel unit through the bidirectional energy storage converter, and the energy storage flywheel unit provides electric energy to the motor inverter 004 through the bidirectional energy storage converter.

The power generation unit 001 is a new energy power station.

The chemical battery array 002 is a lithium battery array, and the first power generation subsystem and the second power generation subsystem share the same lithium battery array 002.

At the position ofA first partIn an embodiment, a computer readable storage medium is provided, the computer readable storage medium storing a computer program, the computer program implementing the steps of the control method of the grid-connected power generation system according to any one of the above when being executed by a processor.

As shown in fig. 5, in one embodiment, a system controller of a grid-connected power generation system is provided, including a memory 012 and a processor 011, where the memory 012 stores a computer program that can be executed on the processor 011, and the processor 011 executes the computer program to implement the steps of the control method of the grid-connected power generation system described in any one of the foregoing steps.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims

1. A control method of a grid-connected power generation system, the method being applied to a grid-connected power generation system, wherein the grid-connected power generation system comprises: the system comprises a first power generation subsystem, a second power generation subsystem and a grid-connected switch, wherein the first power generation subsystem comprises a chemical battery array, an energy storage flywheel array, a motor inverter and a synchronous motor pair which are sequentially connected, the second power generation subsystem comprises a chemical battery array and a bidirectional converter which are sequentially connected, the chemical battery array is used for being connected with a power generation unit and taking power from the power generation unit, the synchronous motor pair is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch, and the bidirectional converter is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch;

The method comprises the following steps:

acquiring the current load power of the alternating current power grid;

when the load power is larger than the first preset value, controlling the energy storage flywheel array to increase power output, and when the energy storage flywheel array is in a full-power working state and the energy storage flywheel array does not meet the power output requirement corresponding to the load power, controlling the second power generation subsystem to output electric energy to the alternating current power grid;

the grid-connected power generation system further includes: the detection device is also used for detecting first residual energy data corresponding to the chemical battery array and second residual energy data corresponding to the energy storage flywheel array;

the method further comprises the steps of:

acquiring the power generated by the power generation unit;

when the generated power is larger than a second preset value, judging whether the first residual energy data is larger than a preset first threshold value or not;

if so, judging whether the second residual energy data is larger than a preset second threshold value or not;

when the second residual energy data is larger than the second threshold value, sending a signal for stopping power transmission to the power generation unit or controlling the chemical battery array to release electric energy to target load equipment;

When the second residual energy data is smaller than or equal to the second threshold value, controlling the chemical battery array to release electric energy to the energy storage flywheel array according to the generated energy of the generating unit;

after the step of obtaining the generated power of the generating unit, the method further includes:

when the generated power is smaller than a third preset value, summing the residual energy value corresponding to the chemical battery array and the residual energy value corresponding to the energy storage flywheel array to obtain a total residual energy value;

when the total value of the residual energy is smaller than the minimum required value of the system energy corresponding to the grid-connected power generation system, controlling the second power generation subsystem to absorb electricity from the alternating current power grid, and controlling the first power generation subsystem to enter a standby operation mode;

and when the total value of the residual energy is greater than or equal to the minimum required value of the system energy, controlling the first power generation subsystem to enter a low-power output mode.

2. The control method of a grid-connected power generation system according to claim 1, wherein the detection means is configured to detect a grid instantaneous frequency of the ac grid;

the method further comprises the steps of:

acquiring a frequency deviation value between the instantaneous frequency of the power grid and a preset rated frequency of the power grid;

When the frequency deviation value is positive and larger than a preset positive dead zone frequency or the frequency deviation value is negative and smaller than a preset negative dead zone frequency, calculating a power compensation value for primary frequency modulation according to the frequency deviation value;

when the absolute value of the power compensation value is larger than the reserved power generation power of the synchronous motor pair, controlling the first power generation subsystem and the second power generation subsystem to work simultaneously for primary frequency modulation;

and when the power compensation value is smaller than or equal to the reserved generated power of the synchronous motor pair, controlling the first power generation subsystem to work for primary frequency modulation.

3. The method for controlling a grid-connected power generation system according to claim 2, wherein the step of controlling the first power generation subsystem and the second power generation subsystem to operate simultaneously to perform primary frequency modulation comprises:

when the frequency deviation value is positive and larger than a preset forward dead zone frequency, controlling the energy storage flywheel array to reduce power output, and controlling the second power generation subsystem to absorb active power from the alternating current power grid;

and when the frequency deviation value is negative and smaller than a preset negative dead frequency, controlling the energy storage flywheel array to increase power output, and controlling the second power generation subsystem to output active power to the alternating current power grid.

4. The control method of a grid-connected power generation system according to claim 2, further comprising, after the step of obtaining the generated power of the power generation unit:

when the generated power is smaller than a third preset value, acquiring the frequency deviation value between the instantaneous frequency of the power grid and the preset rated frequency of the power grid;

when the frequency deviation value is negative, obtaining a frequency change rate corresponding to the instantaneous frequency of the power grid;

and when the frequency change rate is in a preset slow increasing range, controlling the energy storage flywheel array to increase power output.

5. The control method of a grid-connected power generation system according to claim 1, characterized in that the method further comprises:

acquiring a system starting instruction;

responding to the system starting instruction, controlling the chemical battery array to take electricity from the power generation unit so as to realize energy storage of the chemical battery array, and controlling the energy storage flywheel array to take electricity from the chemical battery array so as to realize energy storage of the energy storage flywheel array when the first residual energy data is larger than a preset third threshold value;

and when the second residual energy data is larger than a preset fourth threshold value, controlling the grid-connected switch to be closed so as to realize grid connection through the first power generation subsystem.

6. The control method of a grid-connected power generation system according to claim 2, wherein the pair of synchronous motors includes: the synchronous motor and the synchronous generator are coaxially and rigidly connected; the synchronous motor is connected with the motor inverter, the synchronous motor can drive the synchronous generator to synchronously rotate for generating power, and the synchronous generator is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch;

7. The method according to claim 1, wherein the first power generation subsystem further comprises a first parallel-network transformer, an input end of the first parallel-network transformer is connected to the pair of synchronous motors, and an output end of the first parallel-network transformer is connected to the grid-connected switch and is connectable to the ac grid via the grid-connected switch; and/or the number of the groups of groups,

8. The control method of a grid-connected power generation system according to claim 1, wherein the energy storage flywheel array includes: the system comprises a plurality of energy storage flywheel units, a plurality of bidirectional energy storage converters and an energy storage flywheel array controller, wherein the energy storage flywheel units are in one-to-one correspondence with the bidirectional energy storage converters, and the energy storage flywheel array controller is connected with each bidirectional energy storage converter; the chemical battery array charges the energy storage flywheel unit through the bidirectional energy storage converter, and the energy storage flywheel unit provides electric energy for the motor inverter through the bidirectional energy storage converter.

9. The control method of a grid-connected power generation system according to claim 1, wherein the power generation unit is a new energy power station.

10. The method for controlling a grid-connected power generation system according to claim 1, wherein the chemical battery array is a lithium battery array, and the first power generation subsystem and the second power generation subsystem share the same lithium battery array.

11. A grid-tied power generation system, comprising: the system comprises a system controller, a first power generation subsystem, a second power generation subsystem and a grid-connected switch, wherein the first power generation subsystem comprises a chemical battery array, an energy storage flywheel array, a motor inverter and a synchronous motor pair which are sequentially connected, the second power generation subsystem comprises a chemical battery array and a bidirectional converter which are sequentially connected, the chemical battery array is used for being connected with a power generation unit and taking power from the power generation unit, the synchronous motor pair is connected with the grid-connected switch and can be connected with an alternating current power grid through the grid-connected switch, and the bidirectional converter is connected with the grid-connected switch and can be connected with the alternating current power grid through the grid-connected switch; the system controller comprises a memory storing a computer program and a processor adapted to implement the steps of the control method of a grid-connected power generation system as claimed in any one of claims 1 to 10 when the computer program is executed.

12. A computer-readable storage medium storing a computer program, wherein the computer program when executed by a processor implements the steps of the control method of a grid-connected power generation system as claimed in any one of claims 1 to 10.

13. A system controller of a grid-connected power generation system, comprising a memory, a processor, the memory storing a computer program executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the control method of a grid-connected power generation system as claimed in any one of claims 1 to 10.