Control method based on networking type flywheel energy storage and new energy station integration
By integrating grid-type flywheel energy storage with new energy power plants, the control method dynamically adjusts the rotational inertia and damping coefficient, solving the inertia response and stability problems of traditional flywheel energy storage and new energy power plants in microgrids. This achieves improved frequency and voltage stability and reduces power regulation response time by more than 40%.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENYANG INST OF ENG
- Filing Date
- 2026-01-28
- Publication Date
- 2026-05-01
AI Technical Summary
Traditional flywheel energy storage grid-side converters rely on phase-locked loops to achieve synchronization with the grid, which cannot provide inertial response. The output power fluctuations of new energy power plants lead to a decrease in the frequency and voltage stability of microgrids. Virtual synchronous generator control is difficult to balance dynamic response speed and system stability under disturbances.
The control method of integrating grid-type flywheel energy storage with new energy power stations is adopted. Through the control of the generator-side converter, grid-side converter and adaptive parameter virtual synchronous generator, the rotational inertia and damping coefficient are dynamically adjusted. Combined with the dual closed-loop control of permanent magnet direct-drive wind turbine and photovoltaic cell, stable output of active and reactive power is achieved.
It improves the frequency and voltage stability of microgrids under complex disturbances, reducing frequency fluctuations by 33%-40%, voltage fluctuations by 30%, and DC bus voltage fluctuations by 56.25%-60%, thereby improving the system's anti-interference capability and energy utilization efficiency.
Smart Images
Figure CN121965831A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of microgrid control and new energy technology, and in particular relates to a control method based on the integration of grid-type flywheel energy storage and new energy power stations. Background Technology
[0002] Flywheel energy storage has become an ideal choice for power-grade energy storage due to its long cycle life, high operating efficiency, and strong environmental adaptability. However, traditional flywheel energy storage grid-side converters adopt grid-following control and rely on phase-locked loops to achieve synchronization with the grid. They can only provide specific active and reactive power and lack inertial response capability, which cannot compensate for the weak grid structure defects of new energy units.
[0003] New energy power plants (such as wind power and photovoltaic power) are affected by natural conditions, resulting in strong fluctuations in output power and a decrease in the frequency and voltage stability of microgrids. In existing technologies, although virtual synchronous generator (VSG) control can simulate the characteristics of synchronous machines, the fixed parameters of the VSG make it difficult to balance dynamic response speed and system stability when facing disturbances such as wind speed, sunlight, and load, resulting in problems such as large frequency fluctuations and voltage adjustment lag.
[0004] Therefore, there is an urgent need for a control method that integrates grid-type flywheel energy storage and new energy power stations to improve the stability of microgrids under complex disturbances by dynamically optimizing control parameters. Summary of the Invention
[0005] This invention addresses the shortcomings of existing technologies by providing a control method based on the integration of grid-type flywheel energy storage with new energy power stations.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a control method based on the integration of grid-type flywheel energy storage with new energy power stations, comprising:
[0007] An integrated system model was constructed, which includes a permanent magnet direct-drive wind turbine, photovoltaic cells and grid-type flywheel energy storage. The flywheel energy storage consists of a turbine-side converter, a grid-side converter and a dual-condition motor.
[0008] Maximum power point tracking control is implemented for the permanent magnet direct-drive wind turbine. Specifically, it is achieved through dual closed-loop control of the speed outer loop and current inner loop of the machine-side converter, and dual closed-loop control of the voltage outer loop and current inner loop of the grid-side converter, so as to realize stable output of active power and regulation of reactive power.
[0009] Maximum power point tracking is achieved for the photovoltaic cells using the perturbation-observation method. The DC bus voltage is controlled by a DC / DC converter, and reactive power control is achieved in conjunction with an inverter.
[0010] Vector control is used for the flywheel energy storage generator on the machine side, and motor speed and torque control are achieved through Park transformation and space vector pulse width modulation; an adaptive parameter virtual synchronous generator control strategy is used for the grid-side converter, and the moment of inertia and damping coefficient are dynamically adjusted based on the active-frequency and reactive-voltage droop characteristics of the virtual synchronous generator.
[0011] Using step changes in wind speed, light intensity, and load as disturbance conditions, the simulation verifies the effect of the control strategy on improving the frequency, voltage, and DC bus stability of the microgrid.
[0012] Furthermore, the mathematical model of the permanent magnet direct-drive wind turbine includes the wind turbine mechanical power equation:
[0013]
[0014] in, For the mechanical power of the wind turbine, Where S is the air density and S is the swept area of the wind turbine blades. For wind speed, The wind energy utilization coefficient, For the tip speed ratio, The pitch angle;
[0015] Tip speed ratio , The angular velocity of the wind turbine. The equivalent radius of the wind turbine. This refers to the wind turbine speed.
[0016] Furthermore, in the machine-side converter control of the permanent magnet direct-drive wind turbine, the motor speed is obtained through the rotor position sensor, and a control strategy with an excitation current reference value of 0 is adopted to generate a torque current reference value.
[0017] Furthermore, the mathematical model of the photovoltaic cell includes the current-voltage characteristic equation:
[0018]
[0019] Where I is the output current and U is the output voltage. For photocurrent, Let q be the reverse saturation current, q be the charge constant, A be the diode quality factor, k be the Boltzmann constant, and T be the battery temperature. For series resistance, It is a parallel resistor.
[0020] Furthermore, the energy storage equation for the flywheel energy storage is as follows:
[0021]
[0022] Where E represents stored energy and J represents the flywheel's moment of inertia. The flywheel's rotational angular velocity is: The maximum energy released is:
[0023] These represent the highest and lowest speeds of the flywheel, respectively.
[0024] Furthermore, in the adaptive parameter virtual synchronous generator control strategy, the active power control equation is:
[0025] in, Electric angular velocity, For mechanical power, Where is the electromagnetic power, and Dp is the damping coefficient. Rated electric angular velocity;
[0026] The adaptive adjustment formulas for moment of inertia and damping coefficient are as follows:
[0027]
[0028] in, As the baseline value, For adjustment coefficients, For angular velocity deviation, This is the threshold for change.
[0029] Furthermore, the dynamic adjustment logic of the adaptive parameter virtual synchronous generator control strategy is as follows:
[0030] When the frequency deviation and the rate of change of frequency have the same sign, the system oscillation can be suppressed by increasing the moment of inertia;
[0031] When the absolute value of the frequency deviation increases, frequency convergence can be accelerated by increasing the damping coefficient.
[0032] Furthermore, the disturbance conditions include:
[0033] (1) The wind speed changes in the following steps: 0s-0.5s is 7m / s, 0.5s-1s is 8m / s, and 1s-2s is 7m / s;
[0034] (2) The light intensity changes in the following step manner: 0s-0.4s is 1000W / m², 0.4s-0.9s is 1200W / m², and 0.9s-2s is 900W / m²;
[0035] (3) Load switching is as follows: 10kW active load is switched on at 1.3s, and 2kVar reactive load is switched on at 1.5s.
[0036] A control system for performing a control method includes:
[0037] The model building module is used to construct an integrated system model of permanent magnet direct-drive wind turbine, photovoltaic cell and flywheel energy storage;
[0038] The fan control module is used to achieve maximum power tracking and power regulation of the permanent magnet direct drive fan;
[0039] The photovoltaic control module is used to achieve maximum power point tracking and grid connection control of photovoltaic cells;
[0040] The flywheel control module includes a machine-side vector control unit and a grid-side adaptive VSG control unit, wherein the grid-side adaptive VSG control unit is used to dynamically adjust the moment of inertia and damping coefficient.
[0041] The simulation verification module is used to output the evaluation results of frequency, voltage and DC bus stability under the disturbance conditions of wind speed, light intensity and load step.
[0042] Furthermore, the flywheel control module's machine-side vector control unit includes:
[0043] The speed detection unit is used to obtain the actual speed of the motor;
[0044] The PI control unit is used to convert the speed deviation into a torque current reference value;
[0045] The coordinate transformation unit is used to convert the three-phase current into dq axis components via Clark transformation and Park transformation;
[0046] The space vector pulse width modulation unit is used to generate inverter switching signals.
[0047] A terminal includes a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the above method.
[0048] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the above-described method.
[0049] Compared with the prior art, the present invention has the following advantages.
[0050] This invention breaks through the limitations of traditional flywheel energy storage and grid control. By using the virtual synchronous generator (VSG) control strategy of the grid-side converter, it simulates the active frequency and voltage support characteristics of synchronous generator sets, thus making up for the weak grid structure defects of new energy units (permanent magnet direct-drive wind turbines and photovoltaic cells). Attached Figure Description
[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.
[0052] Figure 1 This is a system architecture diagram of a new energy power station that takes into account wind, solar and energy storage.
[0053] Figure 2 This is a topology diagram of a permanent magnet direct-drive wind turbine generator set.
[0054] Figure 3 This is the circuit diagram of the equivalent circuit of a photovoltaic cell.
[0055] Figure 4 This is a schematic diagram of a flywheel energy storage system and device.
[0056] Figure 5 This is a schematic diagram of a flywheel energy storage system converter.
[0057] Figure 6 This is a schematic diagram of vector control.
[0058] Figure 7 shows the control block diagram of the active power component of the VSG.
[0059] Figure 8. Control block diagram of the reactive power link in VSG.
[0060] Figure 9-a This is a schematic diagram of adaptive control.
[0061] Figure 9-b This is a schematic diagram of the adaptive control principle for rotational inertia.
[0062] Figure 9-c This is a schematic diagram of the damping coefficient adaptive control principle.
[0063] Figure 10 This is a microgrid simulation model diagram.
[0064] Figure 11 This is a schematic diagram of the inverter output frequency under different control strategies.
[0065] Figure 12 This is a schematic diagram of the inverter output voltage under different control strategies.
[0066] Figure 13 This is a schematic diagram showing the changes in DC voltage under different control strategies. Detailed Implementation
[0067] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0068] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The singular forms “a,” “the,” and “the” as used in the embodiments of this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.
[0069] Depending on the context, words such as “if” or “suppose” used here can be interpreted as “when”, “in response to determination”, or “in response to detection”.
[0070] For ease of understanding, the embodiments of this disclosure will be described in detail first.
[0071] like Figure 1-13 As shown in the embodiment, a control method based on the integration of grid-type flywheel energy storage with new energy power stations is adopted. It uses an adaptive parameter virtual synchronous generator control strategy to realize the grid-type operation of flywheel energy storage, make up for the weak grid defects of new energy, and improve the stability of microgrid.
[0072] The specific steps include:
[0073] S1: Establish an integrated system model.
[0074] The new energy power station includes permanent magnet direct-drive wind turbines and photovoltaic cells. The flywheel energy storage system includes a high-speed flywheel rotor, a dual-mode motor, a turbine-side converter, and a grid-side converter. The system architecture is shown in Figure 1. The permanent magnet direct-drive wind turbines are connected to the common bus via turbine-side and grid-side converters. The photovoltaic cells are connected to the bus via DC / DC converters and inverters. The flywheel energy storage system is connected to the bus via a bidirectional converter, together supplying power to the load.
[0075] S2: Control strategy for new energy power stations.
[0076] Specifically, S2 includes:
[0077] S2.1, Permanent magnet direct drive fan control.
[0078] Maximum power point tracking (MPPT) control is employed to adjust the turbine speed according to wind speed, thereby maximizing the wind energy utilization coefficient C. pMaximizing power output. The generator-side converter employs a dual closed-loop control system: an outer speed loop and an inner current loop. The outer speed loop uses a PI regulator to convert the deviation between the actual speed and the reference speed into a torque current reference value; the inner current loop uses a PI regulator to control the dq-axis current to track the reference value. The grid-side converter employs a dual closed-loop control system: an outer voltage loop stabilizes the DC bus voltage, and the inner current loop controls the grid-connected current to achieve reactive power regulation.
[0079] S2.2, Photovoltaic cell control.
[0080] MPPT is achieved using the perturbation-observation method: by applying a small perturbation to the output voltage, comparing the power change trend, and adjusting the voltage to the maximum power point. The DC / DC converter uses a Boost circuit to stabilize the DC bus voltage; the inverter uses an inner current loop and an outer voltage loop control to achieve zero reactive power output and realize unity power factor grid connection.
[0081] S3: Flywheel energy storage control strategy.
[0082] Specifically, S3 includes:
[0083] S3.1, Vector control of machine-side converter.
[0084] The motor speed is obtained through a rotor position sensor, compared with a reference speed, and then output as a torque current reference value (excitation current reference value is 0) via a PI regulator. The three-phase stator current is converted to... The dq-axis component is converted to the dq-axis component via Park transform. After comparison with the reference value, the dq-axis voltage is output by a PI controller and then obtained via inverse Park transform. The shaft voltage is used to generate switching signals through space vector pulse width modulation (SVPWM) to control the operation of the machine-side converter.
[0085] S3.2 Adaptive VSG control for grid-side converters.
[0086] Active power control: Based on the active-frequency droop characteristics of a virtual synchronous generator, the virtual mechanical power is adjusted. To achieve frequency support, the moment of inertia J and damping coefficient D are dynamically adjusted: when the frequency deviation and the rate of change have the same sign, J is increased to suppress oscillation; when the absolute value of the frequency deviation increases, D is increased to accelerate convergence.
[0087] Reactive power control: Based on the reactive power-voltage droop characteristics, voltage support is achieved by adjusting the virtual excitation voltage to compensate for grid voltage fluctuations.
[0088] S4. Simulation verification.
[0089] A microgrid model was built in Matlab / Simulink, with the following perturbation conditions set: wind speed of 7 m / s from 0 to 0.5 s, 8 m / s from 0.5 to 1 s, and 7 m / s from 1 to 2 s; light intensity of 1000 W / m² from 0 to 0.4 s, 1200 W / m² from 0.4 to 0.9 s, and 900 W / m² from 0.9 to 2 s; and a 10 kW active load was applied at 1.3 s, and a 2 kVar reactive load was applied at 1.5 s.
[0090] Simulation results show that under adaptive parameter VSG control, the frequency fluctuation amplitude is reduced by 33%-40% and the voltage fluctuation is reduced by 30% compared with the fixed parameter control, and the DC bus voltage fluctuation is reduced by 56.25%-60%, verifying the effectiveness of the strategy.
[0091] 1. This invention overcomes the limitations of traditional flywheel energy storage and grid-based control. Through a virtual synchronous generator (VSG) control strategy using the grid-side converter, it simulates the active frequency and voltage support characteristics of synchronous generator sets, compensating for the weak grid connection defects of new energy units (permanent magnet direct-drive wind turbines, photovoltaic cells). The provided virtual inertia can effectively improve the frequency change rate under disturbances, reducing frequency fluctuation amplitude by 33%-40% compared to traditional grid-based control, providing crucial dynamic stability support for microgrids.
[0092] 2. This invention innovatively employs a collaborative adaptive control strategy using rotational inertia (J) and damping coefficient (D). Parameters are dynamically adjusted based on the virtual rotor angular velocity deviation and rate of change, solving the problem of balancing response speed and stability under complex disturbances with fixed-parameter VSG. Under wind speed, illumination, and load step disturbances, the DC bus voltage fluctuation amplitude is reduced by 56.25%-60% compared to fixed-parameter control, and voltage fluctuation is reduced by 30%, significantly improving the system's anti-interference capability.
[0093] 3. This invention achieves rapid mitigation of power output fluctuations from renewable energy sources through deep integration of MPPT dual-closed-loop control for permanent magnet direct-drive wind turbines, disturbance observation-based MPPT control for photovoltaic cells, and grid-based control for flywheel energy storage. Simulation results show that in typical disturbance scenarios (such as wind speed 7m / s→8m / s, solar irradiance 1000W / m²→1200W / m²), the system can balance power deficits or surpluses within milliseconds, reducing power regulation response time by more than 40% compared to a single renewable energy control mode, thus improving the overall energy utilization efficiency of the microgrid.
[0094] 4. The control strategy proposed in this invention is verified through Matlab / Simulink simulation and can be directly adapted to existing permanent magnet direct-drive wind turbines, photovoltaic inverters, and flywheel energy storage hardware architectures without large-scale equipment modifications. Through modular design (independent modules for wind turbine control, photovoltaic control, and flywheel VSG control), it supports flexible expansion of new energy power plants of different capacities, providing a feasible technical solution for the engineering application of "new energy + energy storage" microgrids.
[0095] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "preferred embodiment," "detailed description," or "preferred embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Therefore, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.
Claims
1. A control method based on the integration of grid-type flywheel energy storage with new energy power stations, characterized in that, include: An integrated system model was constructed, which includes a permanent magnet direct-drive wind turbine, photovoltaic cells and grid-type flywheel energy storage. The flywheel energy storage consists of a turbine-side converter, a grid-side converter and a dual-condition motor. Maximum power point tracking control is implemented for the permanent magnet direct-drive wind turbine. Specifically, it is achieved through dual closed-loop control of the speed outer loop and current inner loop of the machine-side converter, and dual closed-loop control of the voltage outer loop and current inner loop of the grid-side converter, so as to realize stable output of active power and regulation of reactive power. Maximum power point tracking is achieved for the photovoltaic cells using the perturbation-observation method, the DC bus voltage is controlled by a DC / DC converter, and reactive power control is achieved in conjunction with an inverter. Vector control is used for the flywheel energy storage machine-side converter, and motor speed and torque control are achieved through Park transformation and space vector pulse width modulation; an adaptive parameter virtual synchronous generator control strategy is used for the grid-side converter, and the moment of inertia and damping coefficient are dynamically adjusted based on the active-frequency and reactive-voltage droop characteristics of the virtual synchronous generator. Using step changes in wind speed, light intensity, and load as disturbance conditions, the simulation verifies the effect of the control strategy on improving the frequency, voltage, and DC bus stability of the microgrid.
2. The control method according to claim 1, characterized in that, The mathematical model of the permanent magnet direct-drive wind turbine includes the wind turbine mechanical power equation: in, For the mechanical power of the wind turbine, Where S is the air density and S is the swept area of the wind turbine blades. For wind speed, The wind energy utilization coefficient, For the tip speed ratio, The pitch angle; Tip speed ratio , The angular velocity of the wind turbine. Let n be the equivalent radius of the wind turbine, and n be the wind turbine speed.
3. The control method according to claim 1, characterized in that, In the control of the machine-side converter of a permanent magnet direct-drive wind turbine, the motor speed is obtained through a rotor position sensor, and a control strategy with an excitation current reference value of 0 is adopted to generate a torque current reference value.
4. The control method according to claim 1, characterized in that, The mathematical model of the photovoltaic cell includes the current-voltage characteristic equation: Where I is the output current and U is the output voltage. For photocurrent, Let q be the reverse saturation current, q be the charge constant, A be the diode quality factor, k be the Boltzmann constant, and T be the battery temperature. For series resistance, It is a parallel resistor.
5. The control method according to claim 1, characterized in that, The energy storage equation for the flywheel energy storage is: Where E represents stored energy and J represents the flywheel's moment of inertia. The flywheel's rotational angular velocity is: The maximum energy released is: These represent the highest and lowest speeds of the flywheel, respectively.
6. The control method according to claim 1, characterized in that, In the adaptive parameter virtual synchronous generator control strategy, the active power control equation is: in, Electric angular velocity, For mechanical power, Where is the electromagnetic power, and Dp is the damping coefficient. Rated electric angular velocity; The adaptive adjustment formulas for moment of inertia and damping coefficient are as follows: in, As the baseline value, For adjustment coefficients, For angular velocity deviation, and This is the threshold for change.
7. The control method according to claim 6, characterized in that, The dynamic adjustment logic of the adaptive parameter virtual synchronous generator control strategy is as follows: When the frequency deviation and the rate of change of frequency have the same sign, the system oscillation can be suppressed by increasing the moment of inertia J. When the absolute value of the frequency deviation increases, frequency convergence can be accelerated by increasing the damping coefficient D.
8. The control method according to claim 1, characterized in that, The disturbance conditions include: (1) The wind speed changes in the following step manner: 0s-0.5s is 7m / s, 0.5s-1s is 8m / s, and 1s-2s is 7m / s; (2) The light intensity changes stepwise as follows: 1000W / m² from 0s to 0.4s, 1200W / m² from 0.4s to 0.9s, and 900W / m² from 0.9s to 2s; (3) Load switching is as follows: 10kW active load is switched on at 1.3s, and 2kVar reactive load is switched on at 1.5s.
9. A control system for performing the control method as described in any one of claims 1 to 8, characterized in that, include: The model building module is used to construct an integrated system model of permanent magnet direct-drive wind turbine, photovoltaic cell and flywheel energy storage; The fan control module is used to achieve maximum power tracking and power regulation of the permanent magnet direct drive fan; The photovoltaic control module is used to achieve maximum power point tracking and grid connection control of photovoltaic cells; The flywheel control module includes a machine-side vector control unit and a grid-side adaptive VSG control unit, wherein the grid-side adaptive VSG control unit is used to dynamically adjust the moment of inertia and damping coefficient. The simulation verification module is used to output the evaluation results of frequency, voltage and DC bus stability under the disturbance conditions of wind speed, light intensity and load step.
10. The control system according to claim 9, characterized in that, The flywheel control module's machine-side vector control unit includes: The speed detection unit is used to obtain the actual speed of the motor; The PI control unit is used to convert the speed deviation into a torque current reference value. The coordinate transformation unit is used to convert three-phase current into dq-axis components via Clark transformation and Park transformation; The space vector pulse width modulation unit is used to generate inverter switching signals.