Power oscillation suppression method and system suitable for diesel-storage multi-port power supply system under low-frequency pulse load

Abstract

The invention discloses a power oscillation suppression method and system suitable for a diesel-storage multi-port power supply system under a low-frequency pulse load, and the method comprises the steps: collecting the output power of each energy storage converter and the active power consumed by a load end under the impact of the low-frequency pulse load; the energy storage converters are properly controlled by multiplying the difference value of the ratio of each energy storage converter to the total capacity of the system and the ratio of the output active power of the energy storage converter to the load consumption active power by the voltage reference value of the energy storage converter and adding the calculation result into the reactive power control link of each energy storage converter. The low-frequency oscillation between the output power of the diesel generator and the output power of the energy storage converter under the impact of the short-time high-overload low-frequency pulse load can be effectively suppressed, and the difference between the output power of the diesel generator and the output power of the energy storage converter is stabilized.

Description

Technical Field

[0001] The present invention relates to the field of diesel-storage multi-port power supply systems and control technologies, and in particular to a method and system for suppressing power oscillations in diesel-storage multi-port power supply systems under low-frequency pulse loads. Background Art

[0002] Due to the incomplete construction and maintenance difficulties of power grids in remote areas, as well as poor power supply reliability, voltage fluctuations, frequency deviations, and short-term power outages are frequent. To ensure reliable power supply to critical loads, a multi-port diesel-storage power supply system is constructed using diesel generators and energy storage systems. However, compared to traditional power grids, this system has limited power capacity, and diesel generators have inherent mechanical inertia and fuel regulation lag, resulting in weak dynamic response capabilities. Especially when low-frequency pulse loads are connected, transient power surges can significantly affect the stability of the multi-port diesel-storage power supply system, easily triggering power oscillations and affecting the system's power supply quality and equipment reliability.

[0003] Low-frequency pulse loads are characterized by large power fluctuations, short durations, and a certain periodicity. Their transient peak power can reach several times the average power, posing a challenge to the stable operation of diesel-storage multi-port power supply systems. Since the regulation capability of diesel generators is limited by mechanical inertia and the dynamic response speed of the speed control system, it is difficult for them to balance sudden changes in power demand in a short period of time. Therefore, in order to suppress system power oscillations and improve the power supply reliability of critical loads, it is usually necessary to rely on the fast response characteristics of energy storage converter units to compensate for load power fluctuations. However, most existing power oscillation suppression methods require obtaining the output power information of the diesel generator and rely on communication to achieve coordinated control. This not only increases the complexity and cost of the system, but also may lead to control failure or instability in the event of communication delays or data loss.

[0004] Diesel-to-storage multi-port power supply systems are prone to severe power oscillations under conditions such as load step disturbances. Currently, researchers primarily employ methods such as system parameter matching or enhanced transient damping to suppress these oscillations. Parameter matching relies on precise measurement, real-time identification, and tuning, making it challenging to implement and exhibiting low robustness. Enhanced transient damping often requires additional information exchange or more complex controller design, and also faces challenges with measurement accuracy and communication latency. Furthermore, these deficiencies are exacerbated by the increasing scale of parallel systems and the impact of non-ideal factors such as low-frequency pulse load disturbances, making power oscillation suppression in diesel-to-storage multi-port power supply systems even more challenging.

[0005] CN119134389A discloses an output angular frequency compensation and vibration suppression method for oilfield impact loads. This method injects a fixed compensation value into the frequency loop of the energy storage converter, thereby suppressing power oscillations without measuring the diesel generator's angular frequency and without relying on communication. However, the compensation value in this scheme only applies to the frequency loop of a single energy storage converter, making it impossible to achieve coordinated power distribution among converters in a multi-port parallel system. Furthermore, this method does not coordinate reactive power and voltage dynamics, making it difficult to simultaneously suppress bus voltage drops and current surges. Furthermore, because the compensation coefficient in this method is a fixed value, it is difficult to adaptively adjust to changes in pulse load amplitude and energy storage capacity, resulting in potential under-compensation or over-compensation under high-amplitude, low-frequency pulse load conditions. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology and provide a power oscillation suppression method and system suitable for a diesel-storage multi-port power supply system under low-frequency pulse loads, thereby solving the power oscillation problem caused by differences in design parameters between the diesel generator and the energy storage converter, and quickly responding to the safe and stable operation of the diesel-storage multi-port power supply system under low-frequency pulse loads.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a method for suppressing power oscillations in a diesel-storage multi-port power supply system under low-frequency pulse loads, comprising the following steps:

[0008] Sample the three-phase output voltage and three-phase output current of each energy storage converter and calculate the output active power P of each energy storage converter n and output reactive power Q n ; Sample the three-phase voltage and three-phase current flowing through the load end, and calculate the active power P consumed by the load end Load ; Wherein, n represents the nth energy storage converter;

[0009] Using the output active power P of each energy storage converter n , active power reference value P nref and angular velocity reference value ω ref Calculate the angular velocity ω output by each energy storage converter n ; Using the output active power P of each energy storage converter n , active power consumed by the load P Load , voltage reference value E ref The ratio of the rated capacity of the energy storage converter to the total rated capacity of the diesel-storage multi-port power supply system λ n , calculate the reference voltage compensation value E of each energy storage converter ncal ;

[0010] Using the output reactive power Q of each energy storage converter n, Energy storage converter reference voltage compensation value E ncal , reactive power reference value Q of energy storage converter nref and voltage reference value E ref Calculate the output electromotive force E of the energy storage converter n ;

[0011] According to the angular velocity ω output by the energy storage converter n and the output electromotive force E of the energy storage converter n , the voltage control signal output by the nth energy storage converter is PWM modulated to obtain a three-phase modulated wave.

[0012] The present invention can calculate the output power of each energy storage converter and the total load power after the impact load is applied by detecting the three-phase voltage and three-phase current at the output end and the load end of each energy storage converter without detecting various parameters of the diesel generator set and the output active power and reactive power. The voltage reference compensation value is obtained through calculation, and the output voltage of the energy storage converter is quickly adjusted using the reference voltage compensation value, thereby reducing the power difference between the energy storage converter and the diesel generator. The power oscillation problem of the diesel-storage multi-port power supply system under low-frequency pulse load can be effectively suppressed, thereby ensuring the power supply reliability of the system.

[0013] The voltage, current and other data used in the control link of the present invention can be directly detected by the voltage and current data acquisition module on the main circuit and processed in real time by the control chip. Therefore, there is no need to consider data loss and transmission delay during the communication process. Moreover, the control method proposed in the present invention can directly use the power calculation value to compensate the system reference voltage, omitting the measurement link of various parameters and angular frequency of the diesel generator, reducing the complexity of program operation while avoiding inaccurate control caused by excessive deviation between the measurement of various parameters and angular frequency of the diesel generator and the actual value.

[0014] The multi-port voltage compensation method proposed in the present invention couples "converter capacity ratio-active power imbalance" to form a voltage reference compensation amount and injects it into the voltage loop, thereby realizing rapid coordinated support of active and reactive power of multiple energy storage converters under the conditions of no angular frequency / angular acceleration measurement and no inter-port communication; in addition, the compensation amount of this method naturally decays to zero in steady state without changing the original droop characteristics, thereby effectively overcoming the defects of CN119134389A in multi-port scalability, reactive-voltage coordination and parameter setting.

[0015] In the present invention, the angular velocity ω output by the energy storage converter is n The calculation formula is:

[0016]

[0017] Among them, J nand D n are the moment of inertia and damping coefficient of the nth energy storage converter respectively.

[0018] Energy storage converter reference voltage compensation value E ncal The calculation formula is:

[0019] E ncal =(λ n -P n / P Load )·E ref ;

[0020] in, P gk represents the rated power of the kth diesel generator.

[0021] Energy storage converter output electromotive force E n The calculation formula is:

[0022]

[0023] Among them, K np and D nq They respectively represent the proportional coefficient and reactive droop coefficient of the reactive power control link of the nth energy storage converter.

[0024] As an inventive concept, the present invention also provides a power oscillation suppression system suitable for a diesel-storage multi-port power supply system under low-frequency pulse load, comprising a memory, a processor and a computer program stored on the memory; the processor executes the computer program to implement the steps of the above method.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Under the impact of low-frequency pulse load, the output power of each energy storage converter and the active power consumed by the load are collected. By multiplying the difference between the ratio of each energy storage converter to the total system capacity and the ratio of the active power output of the energy storage converter to the active power consumed by the load by the voltage reference value of the energy storage converter, and adding the calculated result to the reactive power control link of each energy storage converter, the energy storage converter is properly controlled. This can effectively suppress the low-frequency oscillation between the output power of the diesel generator and the energy storage converter under the impact of short-term high-overload low-frequency pulse load, and smooth out the output power difference between the two.

[0027] 2. Since the various parameters of the diesel generator are black-boxed and difficult to measure effectively, the present invention only needs to measure the output power of each energy storage converter and the active power consumed by the load end, so as to effectively control each energy storage converter, adjust the voltage reference of the energy storage converter, change its output voltage, and thus affect its output active power, so that its output angular frequency can quickly track the rated angular frequency, thereby achieving the purpose of quickly suppressing power oscillations caused by sudden load changes.

[0028] 3. The present invention calculates the output power of the energy storage converter obtained by measurement, and performs reference voltage compensation on the energy storage converter by generating a reference voltage compensation signal in a certain form. After calculation, it is found that in steady state, the calculated reference voltage compensation value is 0. Therefore, the newly introduced link does not introduce additional steady-state deviation to the excitation link, which shows that the proposed control method does not affect the static power distribution between the diesel generator and the energy storage converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of a diesel-storage multi-port power supply system in an embodiment of the present invention;

[0030] Figure 2 This is a control block diagram of a method for suppressing power oscillations in a diesel-storage multi-port power supply system under low-frequency pulse loads according to an embodiment of the present invention;

[0031] Figure 3 The output power waveform of the diesel-storage power supply system before and after the power oscillation suppression method proposed in the embodiment of the present invention is introduced. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, the diesel-storage multi-port power supply system structure under low-frequency pulse load in the embodiment of the present invention includes at least one diesel generator and at least one energy storage converter, and the load includes general conventional load and low-frequency pulse load. Figure 1 Medium X tg1 ~X tgk is the output impedance of the first to kth diesel generators; X t1 ~X tn is the output impedance of the first to nth energy storage converters; SWg1 ~SW gk SW1~SW2 are the grid-connected switches for the first to kth diesel generators; n u is the grid-connected switch for the first to nth energy storage converters; g1abc ~u gkabc 、i g1abc ~i gkabc are the three-phase voltage and three-phase current output by the first to kth diesel generators respectively; u 1abc ~u nabc 、i 1abc ~i nabc are the three-phase voltage and three-phase current output by the first to k-th energy storage converters respectively; u Labc and i Labc It is the three-phase voltage and three-phase current at the load end; the load three-phase current is the total current, including general conventional load and low-frequency pulse load.

[0035] In an embodiment of the present invention, a diesel generator and an energy storage converter are taken as an example to describe a method and system for suppressing power oscillations of a diesel-storage multi-port power supply system under a low-frequency pulse load.

[0036] like Figure 2 As shown, the power oscillation suppression method and system of the diesel-storage multi-port power supply system under low-frequency pulse load of the embodiment of the present invention include:

[0037] Step 1: Sampling and power calculation

[0038] Sampling the three-phase voltage u output by the energy storage converter abc And the output three-phase current i abc , using the output three-phase voltage u abc And the output three-phase current i abc , calculate the active power P and reactive power Q output by the energy storage converter; sample the three-phase voltage u flowing through the load end Labc and three-phase current i Labc , using the three-phase voltage u flowing through the load end Labc and three-phase current i Labc Calculate the active power P consumed by the load Load .

[0039] Step 2: Calculation of angular velocity and reference voltage compensation values

[0040] The active power P output by the energy storage inverter and the active power reference value P of the energy storage inverter calculated in step 1 are ref and angular velocity reference value ω ref , calculate the angular velocity ω output by the energy storage converter, the specific formula is:

[0041]

[0042] Among them, J and D are the moment of inertia and damping coefficient of the energy storage converter, respectively.

[0043] The active power P output by each energy storage inverter and the active power P consumed by the load end calculated according to step 1 are Load , voltage reference value E ref The reference voltage compensation value E of the energy storage converter is calculated by taking the ratio λ of the rated capacity of the energy storage converter to the total rated capacity of the diesel-storage multi-port power supply system. cal , the specific formula is:

[0044]

[0045] Among them, P g Indicates the rated power of the diesel generator.

[0046] Step 3: Calculate the electromotive force amplitude

[0047] The reactive power Q output by the energy storage inverter calculated in step 1 and the reference voltage compensation value E calculated in step 2 cal , combined with the reactive power reference value Q of the energy storage converter ref and voltage reference value E ref Calculate the output electromotive force of the energy storage converter. The specific formula is:

[0048] E=K p ∫(E ref +E cal )-E+D q (Q ref -Q)dt

[0049] Among them, K p and D q They respectively represent the proportional coefficient and reactive droop coefficient of the reactive power control link of the energy storage converter.

[0050] Step 4: Generate three-phase modulation wave

[0051] According to the angular velocity ω output by the energy storage converter calculated in step 2 and the electromotive force amplitude E output by the energy storage converter calculated in step 3, the voltage control signal output by the energy storage converter is PWM modulated to obtain a three-phase modulated wave.

[0052] like Figure 3As shown in the figure, the output active power waveform of the diesel-storage parallel power supply system before and after the introduction of the proposed power oscillation suppression method in the embodiment of the present invention; in the initial state, the diesel generator and the energy storage converter work together to output power and the output power is evenly distributed. At 0.05s, a low-frequency pulse load is connected. Due to factors such as different line impedances and inconsistent rotational inertia between the diesel generator and the energy storage converter, there is a large power oscillation. After 0.5s, after the power oscillation suppression method proposed in the present invention is introduced, the power difference is significantly reduced and the oscillation is effectively suppressed, indicating that the power oscillation suppression method proposed in the present invention can effectively suppress the power oscillation problem of the diesel-storage power supply system under low-frequency pulse loads and realize equal distribution of the output power of the diesel-storage parallel system.

[0053] Example 2

[0054] Embodiment 2 of the present invention further provides a power oscillation suppression control system for a diesel-storage multi-port power supply system under a low-frequency pulse load corresponding to the above-mentioned embodiment 1, comprising: one or more processors, a memory and one or more programs stored thereon, and when the one or more programs are executed by the one or more processors, the one or more processors implement the steps of the power oscillation suppression method for a diesel-storage parallel power supply system of the above-mentioned embodiment 1 of the present invention. In some implementations, the memory may be a high-speed random access memory (RAM), and may also include a non-volatile memory (Non-Volatile Memory), such as at least one disk storage. In other implementations, the processor may be various types of general-purpose processors such as a central processing unit (CPU), a digital signal processor (DSP), etc., which are not limited here.

[0055] The energy storage converter in the embodiment of the present invention adopts grid-type control, and is therefore applicable to both off-grid operation mode and grid-connected operation mode.

[0056] Example 3

[0057] Embodiment 3 of the present invention provides a computer-readable storage medium corresponding to the above-mentioned embodiment 1, on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the method of the above-mentioned embodiment 1 are implemented.

[0058] Computer readable storage media can be tangible devices that hold and store instructions used by instruction execution devices. Computer readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any combination thereof.

[0059] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt 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.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0061] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0062] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0063] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for suppressing power oscillations in a diesel-storage multi-port power supply system under low-frequency pulse loads, characterized in that: The following steps are involved: Sample the three-phase output voltage and three-phase output current of each energy storage converter and calculate the output active power P of each energy storage converter n and output reactive power Q n ; Sample the three-phase voltage and three-phase current flowing through the load end, and calculate the active power P consumed by the load end Load ; Wherein, n represents the nth energy storage converter; Using the output active power P of each energy storage converter n , active power reference value P nref and angular velocity reference value ω ref Calculate the angular velocity ω output by each energy storage converter n ; Using the output active power P of each energy storage converter n , active power consumed by the load P Load , voltage reference value E ref The ratio of the rated capacity of the energy storage converter to the total rated capacity of the diesel-storage multi-port power supply system λ n , calculate the reference voltage compensation value E of each energy storage converter ncal ; Using the output reactive power Q of each energy storage converter n , Energy storage converter reference voltage compensation value E ncal , reactive power reference value Q of energy storage converter nref and voltage reference value E ref Calculate the output electromotive force E of the energy storage converter n ; According to the angular velocity ω output by the energy storage converter n and the output electromotive force E of the energy storage converter n , the voltage control signal output by the nth energy storage converter is PWM modulated to obtain a three-phase modulated wave.

2. The power oscillation suppression method for a diesel-storage multi-port power supply system under low-frequency pulse load according to claim 1 is characterized in that: Angular velocity ω output by the energy storage converter n The calculation formula is: Among them, J n and D n are the moment of inertia and damping coefficient of the nth energy storage converter respectively.

3. The power oscillation suppression method for a diesel-storage multi-port power supply system under low-frequency pulse load according to claim 1 is characterized in that: Energy storage converter reference voltage compensation value E ncal The calculation formula is: AND ncal =(λ n -P n / P Load )·AND ref 4 in, P gk represents the rated power of the kth diesel generator.

4. The power oscillation suppression method for a diesel-storage multi-port power supply system under low-frequency pulse load according to claim 1 is characterized in that: Energy storage converter output electromotive force E n The calculation formula is: E n =K np ∫(E ref +E ncal )-E n +D nq (Q nref -Q n )dt; Among them, K np and D nq They respectively represent the proportional coefficient and reactive droop coefficient of the reactive power control link of the nth energy storage converter.

5. A power oscillation suppression system for a diesel-storage multi-port power supply system under low-frequency pulse loads, comprising a memory, a processor, and a computer program stored in the memory; characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 4.

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