Power oscillation suppression method for network-constructed diesel storage power supply system under direct-current voltage disturbance

Abstract

The application discloses a method for suppressing power oscillation of a network-constructed diesel and energy storage power supply system under DC voltage disturbance, which comprises two parts of DC voltage feedforward compensation and AC synchronous torque compensation. DC The DC voltage feedforward compensation part constructs a DC feedforward component T D by means of the DC side voltage of an energy storage converter, compensates the energy storage output voltage amplitude in real time by means of the DC feedforward component, and suppresses power oscillation caused by DC side voltage fluctuation; the AC synchronous torque compensation part constructs an AC synchronous torque compensation component T D by means of the output angular frequency of a diesel generator and the energy storage, compensates the energy storage output voltage phase in real time by means of the AC synchronous torque compensation component, and suppresses power oscillation caused by the phase inconsistency between the diesel generator and the energy storage. The application realizes the suppression of power oscillation of the network-constructed diesel and energy storage power supply system under coupling disturbance of the DC side and the AC side, effectively reduces system power oscillation and DC voltage fluctuation, and guarantees safe and reliable operation of the diesel and energy storage power supply system.

Description

Technical Field

[0001] This invention relates to the field of reliable power supply and power oscillation suppression in grid-type diesel-storage power supply systems, and in particular to a method for suppressing power oscillations in grid-type diesel-storage power supply systems under DC voltage disturbances. Background Technology

[0002] In remote areas such as islands, deserts, and rural areas, grid-connected diesel-storage power supply systems, consisting of diesel generators and grid-controlled energy storage converters, are commonly used to provide reliable power supply as an alternative to the main power grid. This system ensures power supply stability and reliability while avoiding the high costs of large-scale grid construction and overcomes the inherent drawbacks of single diesel generators, such as low flexibility, poor economics, and slow response. It is a crucial means of ensuring power supply in these areas. In these systems, the energy storage converter can work in tandem with the diesel generator to share load power variations according to a preset droop coefficient, thereby significantly reducing the capacity requirements of the diesel generator and contributing to system frequency stability.

[0003] However, in grid-connected diesel-storage parallel systems, the diesel generator and the energy storage converter differ significantly in physical structure, control parameters, inertia, and damping characteristics. When the system experiences load disturbances, the rates of change of their output angular frequency and phase are inconsistent, resulting in angular frequency differences and phase deviations between the diesel generator and the energy storage converter. Based on the power angle characteristics of synchronous generators, this phase deviation directly causes a redistribution of active power, leading to low-frequency power oscillations and posing a challenge to the stable operation of the system.

[0004] Existing research on power oscillations in parallel diesel generator and grid-connected energy storage systems focuses on optimizing and adaptively adjusting control parameters in some areas, such as tuning virtual inertia and damping coefficients based on small-signal models, or introducing adaptive virtual impedance to change the system's damping characteristics. However, these methods are complex and have weak adaptability. Other strategies focus on correcting the AC control loop, such as introducing differential feedforward or phase compensators in the active power loop to compensate for low-frequency phase lag. Their compensation effectiveness is highly dependent on the impedance characteristics of the output port and implicitly assumes a strict linear relationship between the modulation input and output response. Furthermore, none of these strategies consider the impact of DC voltage fluctuations on AC power oscillations in actual engineering applications.

[0005] Patent application CN120320362A discloses a method and system for suppressing power oscillations in a grid-connected diesel-storage combined power supply system. However, this implementation scheme does not consider the aggravated power oscillations caused by DC-side voltage fluctuations in the energy storage converter; it only addresses the power oscillation problem on the AC side, failing to resolve the AC / DC power oscillation coupling phenomenon caused by DC voltage fluctuations. Furthermore, the control method for real-time tracking of load power suffers from measurement errors. Therefore, it has significant limitations for practical grid-connected diesel-storage power supply systems.

[0006] In summary, existing power oscillation suppression control strategies, when applied in practical grid-connected diesel-storage power supply systems, exhibit significant dynamic fluctuations in the DC bus voltage due to dynamic delays on the DC side and frequent load switching. These dynamic changes on the DC side lead to changes in the DC bus voltage Vo. dc and active power P E Complex AC / DC coupling effects arise between the two, ultimately exacerbating power oscillations, severely degrading power quality, and shortening the lifespan of diesel generators. Therefore, for practical grid-connected diesel-storage power supply systems, there is an urgent need for methods to suppress power oscillations under DC voltage disturbances. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbance, which effectively suppresses power oscillations in the grid-connected diesel-storage power supply system caused by DC side voltage fluctuations.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances, comprising the following steps:

[0009] S1. Collect the three-phase output voltage and three-phase output current of the grid-type energy storage converter and the diesel generator to obtain the instantaneous active power P of the grid-type energy storage converter. E Reactive power Q E The instantaneous active power P0 and reactive power Q0 of the diesel generator are measured; the DC side of the grid-type energy storage converter is sampled to obtain the DC voltage V at the input side of the grid-type energy storage converter. dc ;

[0010] S2, utilizing the instantaneous active power P of the grid-type energy storage converter E The instantaneous active power P0 of the diesel generator was used to calculate the angular frequency ω of the energy storage converter. E And the angular frequency ω0 of the diesel generator; utilizing the angular frequency ω of the energy storage converter E The AC synchronous torque compensation component T is calculated from the angular frequency ω0 of the diesel generator. D ;Utilizing the DC voltage V on the input side of the grid-type energy storage converter dc The DC feedforward component T is calculated. DC ;

[0011] S3, Utilizing AC synchronous torque compensation component T D The compensated angular frequency ω was calculated. sup For the compensated angular frequency ω sup Integrating the phases yields the compensated phase θ. sup ;Utilizing DC feedforward compensation component T DC Calculate the compensated electromotive force Esup ;

[0012] S4, Based on the compensation phase θ sup and compensation electromotive force E sup The virtual synchronous generator is modulated with PWM to generate the switching drive signal for the energy storage converter.

[0013] This invention introduces AC synchronous torque compensation and DC voltage feedforward compensation to directly incorporate the dynamic DC voltage into the control loop, achieving AC / DC coordinated suppression and fundamentally cutting off the path of increased coupling. Addressing the deficiency in diesel-storage parallel power supply systems that do not consider DC-side dynamics, this invention adds AC synchronous torque and DC feedforward torque to the active and reactive power loops of the grid-type energy storage converter, respectively, achieving the dual effects of AC power oscillation suppression and rapid DC voltage stabilization. This eliminates the need for additional communication links and reduces control response delay.

[0014] This invention introduces an AC synchronous torque compensation branch into the active power loop of the energy storage converter, thereby synchronizing the output angular frequency ω0 of the diesel generator with the output angular frequency ω of the energy storage converter. E Multiply by the difference by the AC synchronous torque coefficient D dm The AC synchronous torque compensation component T is obtained. D The AC synchronous torque compensation component T D When added to the active power loop of the energy storage converter, the compensated angular frequency ω is obtained. sup After integration, the compensated phase component θ is obtained. sup .

[0015] This invention introduces a DC voltage feedforward compensation branch into the reactive power loop of the energy storage converter, thereby reducing the DC side voltage V of the energy storage converter. dc With DC voltage reference value V dcref After subtraction, the DC feedforward compensation component T is obtained by passing it through a first-order low-pass filter. DC The DC feedforward component compensation component T DC When added to the active power loop of the energy storage converter, the compensated angular frequency ω is obtained. sup After integration, the compensated phase component θ is obtained. sup .

[0016] This invention utilizes the integral of the compensated angular frequency to calculate the compensated phase component θ. sup and electric potential E sup PWM modulation is applied to the grid-type energy storage converter to obtain the switching transistor drive signal of the system that suppresses power oscillation caused by AC / DC coupling in the diesel-energy storage parallel power supply system.

[0017] This invention introduces AC synchronous torque compensation and DC voltage feedforward compensation to dynamically and directly introduce the DC side voltage into the control loop, thereby achieving AC / DC coordinated suppression and cutting off the path of increased coupling at its source.

[0018] The voltage and current information used in this invention can be directly detected by the data acquisition module and processed in real time by the control chip, which is simple to implement and has low operational complexity.

[0019] When the system is in steady state, the DC-side voltage of the energy storage converter is equal to the reference value, i.e., V dc =V dcref The steady-state angular frequency values ​​of the diesel generator and the energy storage converter are equal, i.e., ω E =ω0, at which point both the AC synchronous torque compensation component and the DC feedforward compensation component are zero. Therefore, this invention does not affect the steady-state power distribution of the diesel generator and the grid-type energy storage in parallel.

[0020] For AC synchronous torque compensation T D The proposed method calculates the difference in angular frequency between the energy storage converter and the diesel generator, and then modifies this difference with the AC synchronous torque coefficient D. dm Multiply to get T D AC synchronous torque T D The expression is:

[0021] ;

[0022] The AC synchronous torque compensation amount proposed in this invention is mainly composed of the angular frequencies ω0 and ω of the diesel generator and energy storage converter. E The angular frequencies of the two frequencies are obtained by multiplying the difference by the AC synchronous torque coefficient. The angular frequencies of the two frequencies can be obtained from their respective active power loops, as shown in the following formulas:

[0023] ;

[0024] J E J0 represents the virtual moment of inertia of the energy storage converter and the diesel generator, and D... PE and D P0 P represents the virtual damping coefficient of the energy storage converter and the diesel generator. nE and P n0 ω is the active power reference value. E ω0 represents the rated angular frequency of the energy storage converter and the diesel generator.

[0025] This invention obtains the DC feedforward component T by calculating the difference between the DC-side voltage of the energy storage converter and the voltage reference value, and then passing it through a first-order low-pass filter. DC DC feedforward component T DC The expression is:

[0026] ;

[0027] The DC feedforward compensation parameters K and T in the proposed method are adjustable to a certain extent, do not depend on precise values, and do not affect the original energy storage converter control parameters.

[0028] The AC synchronous torque compensation component T D The DC feedforward component T is added to the active loop of the energy storage converter. DC The compensation angular frequency ω of the energy storage converter is finally obtained by adding it to the reactive power loop. sup and compensation electromotive force E sup As shown below:

[0029] ;

[0030] ;

[0031] As an inventive concept, the present invention also provides a power oscillation suppression system for a grid-connected diesel-storage power supply system under DC voltage disturbance, comprising:

[0032] One or more processors;

[0033] A memory having stored one or more programs that, when executed by one or more processors, cause the one or more processors to perform the steps of the method described above.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. This invention addresses the deficiency in parallel diesel-storage power supply systems that do not consider DC-side dynamics. By adding AC synchronous torque and DC feedforward components to the active and reactive power loops of the grid-type energy storage converter, it achieves both AC power oscillation suppression and rapid DC voltage stabilization. Compared to traditional methods, this invention eliminates the need for additional communication links, significantly reducing control response delay and providing efficient assurance for the system's power supply quality. Furthermore, this invention eliminates the need for additional adjustments to the diesel generator's control system when suppressing power oscillations, reducing program complexity and implementation difficulty.

[0036] 2. The voltage and current data used in this invention can be directly detected by the voltage data acquisition module and processed in real time by the control chip, making it simple to implement and with low operational complexity. Furthermore, the DC feedforward compensation in the method proposed in this invention has a certain degree of adjustability for K and T, does not rely on very precise values, and will not affect the original energy storage converter control parameters.

[0037] 3. During steady-state operation of the system, after the suppression method is implemented, the DC-side voltage of the energy storage converter and the DC voltage reference value are equal, i.e., V dc =V dcref The steady-state angular frequency values ​​of the diesel generator and VSG terminal voltages are equal, i.e., ω E=ω0, and the values ​​of the AC synchronous torque compensation component and the DC feedforward compensation component are 0 in steady state. Therefore, this invention does not affect the steady-state power distribution of the diesel generator and the grid-type energy storage in parallel. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the control of a grid-type diesel-storage power supply system in an embodiment of the present invention;

[0039] Figure 2 This is a method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances, as described in this embodiment of the invention.

[0040] Figure 3 The following are simulated waveforms of the output power and DC voltage fluctuation of the energy storage converter and the diesel generator without considering the dynamics of the DC side in the embodiments of the present invention: (a) Output power waveform of the energy storage converter and the diesel generator, (b) DC side voltage waveform of the energy storage converter;

[0041] Figure 4 The following are simulation waveforms of the output power waveform and DC voltage fluctuation of the energy storage converter and the diesel generator under dynamic conditions on the DC side in this embodiment of the invention: (a) Output power waveform of the energy storage converter and the diesel generator, (b) DC side voltage waveform of the energy storage converter;

[0042] Figure 5 The following are simulation waveforms of the output power waveform and DC voltage fluctuation of the energy storage converter and the diesel generator after the suppression method is added in the embodiment of the present invention: (a) Output power waveform of the energy storage converter and the diesel generator, (b) DC side voltage waveform of the energy storage converter. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1As shown, the diesel-storage parallel power supply system in this embodiment includes a diesel generator and an energy storage converter. The DC side of the energy storage converter is connected to the energy storage battery and a supercapacitor, while the AC side is connected to the load via an AC bus. In the two-stage parallel system of the energy storage converter and the diesel generator, the DC side of the front-stage converter uses single-voltage loop control, and the DC side voltage of the rear-stage inverter is controlled to a given value through PI control. Since this embodiment mainly considers the impact of the front-stage DC side voltage on the power oscillation of the rear-stage diesel generator, the specific front-stage topology is not considered. The front-stage converter is equivalent to a combination of a controlled current source and a DC capacitor, as shown below. Figure 1 The output line impedance shown is X. E The diesel generator output line impedance is X0, and the load is a combination of conventional load and dynamic load.

[0046] like Figure 2 As shown, the specific implementation steps of the power oscillation suppression method for a grid-connected diesel-storage power supply system under DC voltage disturbance according to an embodiment of the present invention include:

[0047] Step 1: Sampling and Voltage Amplitude Calculation

[0048] The three-phase output voltage and three-phase output current of a two-stage grid-type energy storage converter are collected to obtain the voltage components u of the energy storage converter on the α-axis and β-axis. Eα u Eβ and current component i Eα i Eβ Subsequently, based on the voltage and current components along the α and β axes, the instantaneous active power P of the energy storage converter is calculated. E and reactive power Q E :

[0049] ;

[0050] The DC side of the two-stage grid-type energy storage converter is sampled to obtain the DC voltage V at the input side of the energy storage converter. dc .

[0051] Collect the three-phase output voltage and three-phase output current of the diesel generator, and obtain the voltage components u of the energy storage converter on the α-axis and β-axis. 0α u 0β and current component i 0α i 0β Subsequently, based on the voltage and current components along the α and β axes, the instantaneous active power P0 and reactive power Q0 of the energy storage converter are calculated:

[0052] ;

[0053] Step 2: Establish a mathematical model for the parallel connection of a two-stage grid-type energy storage converter and a diesel generator.

[0054] The active power P calculated by the energy storage converter in step 1 E and reactive power Q E Substituting these values ​​into the active and reactive power loops of the energy storage converter, we obtain the expressions for active and reactive power as follows:

[0055] ;

[0056] J E D represents the virtual rotational inertia of the energy storage converter. PE D is the virtual active power damping coefficient of the energy storage converter. qE P is the virtual reactive power damping coefficient of the energy storage converter. nE ω is the reference value for the active power of the energy storage converter. n The rated angular frequency, ω E K is the angular frequency of the energy storage converter. s U is the reactive inertia coefficient. pE U is the terminal voltage of the energy storage converter. n This is the rated terminal voltage of the energy storage converter.

[0057] Substituting the active power P0 and reactive power Q0 calculated by the diesel generator in step 1 into the active and reactive power loops of the diesel generator, the small-signal expression for active power is obtained as follows:

[0058] ;

[0059] Where J0 diesel generator virtual moment of inertia, D P0 D is the virtual active power damping coefficient of the diesel generator. qE P is the virtual reactive power damping coefficient of the diesel generator. n0 ω is the reference value for the active power of the diesel generator. n ω0 is the rated angular frequency, K is the diesel generator angular frequency. s U is the reactive inertia coefficient. p0 U is the terminal voltage of the energy storage converter. n This is the rated terminal voltage of the energy storage converter.

[0060] Step 3: Dynamic AC synchronous torque compensation and DC feedforward component

[0061] First, the angular frequency ω of the energy storage converter and diesel generator is used. E The dynamic AC synchronous torque is calculated using ω0, as shown below:

[0062] ;

[0063] Where T D For AC synchronous torque, D dm This is the dynamic mutual damping coefficient.

[0064] Subtracting the DC-side voltage of the two-stage energy storage converter obtained from step 1 from the DC voltage reference value, and then passing the difference through a first-order low-pass filter, yields the DC feedforward component as shown below:

[0065] ;

[0066] Where T DC For DC feedforward component, V dcref Here, is the DC reference voltage value, and K and T are the gain and time constant of the low-pass filter, respectively.

[0067] Step 4: Modulation voltage generation

[0068] The AC synchronous torque compensation component is added to the active power loop of the energy storage converter, and the compensation angular frequency ω is calculated. sup As shown in the following formula:

[0069] ;

[0070] The DC feedforward compensation component is added to the reactive power loop of the energy storage converter, and the compensation electromotive force E is calculated. sup As shown in the following formula:

[0071] ;

[0072] By compensating for angular frequency ω sup The compensated phase component θ is obtained by integral calculation. sup for:

[0073] ;

[0074] Step 5: Generation of drive signals

[0075] The phase θ of the energy storage converter is obtained from the active power loop. sup and output three-phase electromotive force E sup PWM modulation is applied to the grid-type energy storage converter to obtain the switching transistor drive signal that suppresses power oscillation in the diesel-energy storage parallel power supply system. The energy storage converter directly realizes the power response with the diesel generator based on its active and reactive power loops.

[0076] From a physical perspective, the essence of power oscillation lies in the continuous shift of the inter-machine power angle when ω E When ω > 0, it indicates that the phase of the energy storage converter is ahead of the generator and the difference is widening. According to the power angle characteristic, the active power P output by the energy storage converter at this time is... E In an overshoot state; conversely, when ω0 > ω E When this occurs, it indicates that the phase difference is decreasing, and the active power P output by the energy storage converter is increasing. ERelatively insufficient. Based on the above mechanism, the AC synchronous torque compensation component T introduced in the embodiments of the present invention is... D The system will operate as follows, when oscillation occurs and ω0 > ω... E At that time, T D The positive increase is used to increase the angular frequency ω of the energy storage converter. E This increases the instantaneous active power P. E To prevent further phase lag; conversely, when ω E When ω > 0, T D This generates a negative increment that lowers ω E This reduces P E To suppress power overshoot. When the system is in steady state without oscillation, ω0 = ω E At that time, the difference in angular frequency between the two is zero, and the AC synchronous torque compensation component T D It also becomes zero. Simultaneously, in this embodiment of the invention, the extracted DC-side voltage deviation is converted into a DC feedforward component T. DC A reactive power control loop is introduced to compensate for the output potential E. sup This approach aims to smooth out DC bus voltage fluctuations and suppress AC power oscillations. The control strategy in this embodiment achieves both suppression of AC power oscillations and stability of DC voltage during dynamic processes. Furthermore, in steady state, the compensation amount automatically returns to zero, ensuring that the original steady-state power distribution ratio between the diesel generator and the energy storage converter remains unchanged.

[0077] Figure 3 The system dynamic response waveforms under ideal constant DC bus voltage conditions are shown. When the load power jumps from 0 to 1200W, the output power of the energy storage converter and the diesel generator exhibits obvious low-frequency oscillations, with a maximum oscillation amplitude of 1100W. After a transient adjustment process, the system recovers to a steady-state power value of 600W, and the DC bus voltage remains constant at 700V throughout the process.

[0078] Figure 4 The system response waveforms considering dynamic fluctuations in the DC-side voltage are shown. Under the same load step disturbance, the system initially generates power oscillations with an amplitude of approximately 1100W. However, due to the dynamic interaction between the DC bus voltage and the AC-side power, persistent power oscillations persist even after the system reaches steady state, with a peak value of approximately 622W. Simultaneously, the DC bus voltage fluctuation amplitude reaches 730V. This comparison confirms that dynamic fluctuations in the DC-side voltage are the key reason for the exacerbated AC-side power oscillations.

[0079] Figure 5The simulation results demonstrate the dynamic response waveforms of the system after employing the control strategy proposed in this invention, namely, adding an AC synchronous torque compensation component to the active power loop and a DC feedforward compensation component to the reactive power loop. The power oscillation amplitude is reduced to 780W, and the system power recovers to a steady-state value of 600W in a very short time, significantly suppressing the system power oscillation amplitude. Simultaneously, the DC-side voltage fluctuation amplitude is 705V, and it continuously recovers to a steady-state value, with the waveform remaining stable throughout the dynamic process. Simulation results show that the method proposed in this invention not only effectively solves the problems of increased AC power oscillation and DC voltage fluctuation caused by AC-DC coupling, but also automatically returns the compensation amount to zero in steady state, without affecting the steady-state distribution of active power, significantly improving the overall dynamic stability of the diesel-storage parallel power supply system.

[0080] Example 2

[0081] Embodiment 2 of the present invention provides a terminal device corresponding to Embodiment 1 above. The terminal device can be a processing device for a client, such as a mobile phone, a laptop, a tablet computer, a desktop computer, etc., to execute the method of the above embodiments.

[0082] The terminal device in this embodiment includes a memory, a processor, and a computer program stored in the memory; the processor executes the computer program in the memory to implement the steps of the method in Embodiment 1 described above.

[0083] In some implementations, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0084] In other implementations, the processor can be any type of general-purpose processor, such as a central processing unit (CPU) or a digital signal processor (DSP), and there is no limitation here.

[0085] Example 3

[0086] Embodiment 3 of the present invention provides a computer-readable storage medium corresponding to Embodiment 1 above, on which a computer program / instructions are stored. When the computer program / instructions are executed by a processor, they implement the steps of the method of Embodiment 1 above.

[0087] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0088] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0089] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0091] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0092] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances, characterized in that, Includes the following steps: S1. Collect the three-phase output voltage and three-phase output current of the grid-type energy storage converter and the diesel generator to obtain the instantaneous active power P of the grid-type energy storage converter. E Reactive power Q E The instantaneous active power P0 and reactive power Q0 of the diesel generator are measured; the DC side of the grid-type energy storage converter is sampled to obtain the DC voltage V at the input side of the grid-type energy storage converter. dc ; S2, utilizing the instantaneous active power P of the grid-type energy storage converter E The instantaneous active power P0 of the diesel generator was used to calculate the angular frequency ω of the energy storage converter. E And the angular frequency ω0 of the diesel generator; utilizing the angular frequency ω of the energy storage converter E The AC synchronous torque compensation component T is calculated from the angular frequency ω0 of the diesel generator. D ; Utilizing the DC voltage V on the input side of the grid-type energy storage converter dc The DC feedforward component T is calculated. DC ; S3, Utilizing AC synchronous torque compensation component T D The compensated angular frequency ω was calculated. sup For the compensated angular frequency ω sup Integrating the phases yields the compensated phase θ. sup ; Using DC feedforward compensation component T DC Calculate the compensation electromotive force E sup ; S5, Based on the compensation phase θ sup and compensation electromotive force E sup The virtual synchronous generator is modulated with PWM to generate the switching drive signal for the energy storage converter.

2. The method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances according to claim 1, characterized in that, Energy storage converter angular frequency ω E The formula for calculating the angular frequency ω0 of a diesel generator is: ； Among them, J E J0 and D are the virtual moments of inertia of the energy storage converter and the diesel generator, respectively. pE and D p0 P represents the virtual damping coefficients of the energy storage converter and the diesel generator, respectively. nE and P n0 P represents the active power reference values ​​for the energy storage converter and the diesel generator, respectively. E P0 and P1 are the instantaneous active power of the energy storage converter and the diesel generator, respectively.

3. The method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances according to claim 1, characterized in that, The AC synchronous torque compensation component T D The calculation formula is: ； Among them, D dm This is the AC synchronous torque coefficient.

4. The method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances according to claim 1, characterized in that, The compensated angular frequency ω sup The calculation formula is: ； Among them, J E D represents the virtual rotational inertia of the energy storage converter. pE P is the virtual damping coefficient of the energy storage converter. nE ω is the reference value for the active power of the energy storage converter. n t is the rated angular frequency, and t is the sampling time.

5. The method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances according to claim 1, characterized in that, The DC feedforward compensation component T DC Represented as: Where K and T are the gain and time constant of the first-order low-pass filter, respectively, s is the complex frequency, and V is the time constant. dcref This is the reference value for DC voltage.

6. The method for suppressing power oscillations in a grid-connected diesel-storage power supply system under DC voltage disturbances according to claim 1, characterized in that, The compensation electromotive force E sup The calculation formula is: ； Among them, K s D is the reactive inertia coefficient of the energy storage converter. qE Q is the reactive virtual damping coefficient. nE Q is the reference value for reactive power of the energy storage converter. E U represents the instantaneous reactive power of the energy storage converter. pE U is the terminal voltage of the energy storage converter. n This is the rated output voltage of the energy storage converter.

7. A power oscillation suppression system for a grid-connected diesel-storage power supply system under DC voltage disturbance, comprising: One or more processors; A memory having stored one or more programs that, when executed by one or more processors, cause the one or more processors to perform the steps of the method according to any one of claims 1 to 6.

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