CN110266062B - Double-layer self-adaptive inertia control method and device for inverter type distributed power supply - Google Patents

Abstract

A double-layer self-adaptive inertia control method and device for an inverter-type distributed power supply. According to the control topology of the VSG-based IIDG, the relationship between the virtual inertia constant of the VSG and the output angular frequency of the IIDG is obtained, and then a small-signal model is established. Through a small The signal model simulates the actual operation scene, selects the control priority with a double-layer adaptive control strategy between power adjustment and frequency adjustment, so that IIDG can adapt to different operation scenarios; the invention can take into account both output stability and dynamic response speed, and effectively improve system operation performance. Strengthen the control effect.

Description

Inverter-type distributed power double-layer adaptive inertia control method and device

technical field

The invention relates to a technology in the field of smart grids, in particular to a double-layer self-adaptive inertia control method and device for an inverter-type distributed power supply.

Background technique

With the continuous development of renewable energy power generation technology, distributed generators (Distributed generator, DG) have become the main way to use new energy in distribution networks. How to make full use of high-permeability DG and improve its stability is a key problem that needs to be solved urgently. Most of the DGs in the distribution network are inverter power sources, such as photovoltaics and energy storage. Inverter DG (Inverter interfaced DG, IIDG) is not stable enough. Virtual synchronous motor (Virtual synchronous generator, VSG) technology can greatly improve the transient output characteristics of IIDG by simulating the inertia characteristics of synchronous generators and adding virtual inertia control links in the IIDG control strategy, making IIDG a friendly grid-connected power supply, thus Improve the ability of IIDG to participate in the regulation of distribution network operation.

At present, the VSG strategy mainly focuses on the mechanism of frequency stability and the trajectory of the power angle curve, but there are few studies on the mechanism of the influence of output active power under different virtual inertias. Existing literature has shown that the use of large inertia can effectively reduce the output frequency fluctuation and enhance the dynamic stability of the system frequency; however, the use of small inertia can obtain fast and stable output power. The effect of virtual inertia on VSG-IIDG output frequency and power is different. Power adjustment requires small inertia, but if VSG adopts low inertia, the frequency fluctuation will be large, which is not conducive to the stable operation of the system. Therefore, if the two are not considered at the same time, it may lead to poor dynamic response characteristics of VSG-IIDG output power under different operating scenarios, or even fail to meet the power supply requirements.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention proposes a double-layer self-adaptive inertia control method and device for an inverter-type distributed power supply. The virtual inertia used by the VSG controller is a self-adaptive control parameter, which can And the real-time dynamic frequency deviation adaptively adjusts the control priority to meet the system's requirements for the output of the inverter distributed power supply under different operating conditions.

The present invention is achieved through the following technical solutions:

The invention relates to a double-layer self-adaptive inertia control method for an inverter-type distributed power supply, which establishes a small-signal model based on the VSG-based IIDG control topology, and analyzes the relationship between the virtual inertia constant of the VSG and the output angular frequency and active power of the IIDG , and furthermore, through the small signal model to simulate the actual operation scene, the control priority is selected with a two-layer adaptive control strategy between power regulation and frequency regulation, so that IIDG can adapt to different operation scenarios.

The power adjustment refers to: when the active power reference value of the IIDG itself changes suddenly, a smaller virtual inertia constant H is used to adjust the active power;

The frequency adjustment refers to: when the common bus frequency changes in a small range, the virtual inertia constant H is adaptively adjusted according to the IIDG frequency output change, specifically: when the offset is small, the control gives priority to the system adjustment speed, and the output overshoot When the problem is behind, the influence of external fluctuations is suppressed through quick response; when the deviation is large, the control focuses on smoothing the overshoot, and the system response speed is appropriately slowed down.

其中：k_g为一预设系数，k_d则反映了频率偏移权重，k_d越大，实际控制曲线接近于Γ₁；当k_a减小，实际控制曲线接近于Γ₄，则在整个调节过程中虚拟惯量均采用最小值，Γ₁至Γ₄对应的灵敏系数不断减小，Γ₄对应的灵敏系数为零。The control priority refers to that the sensitivity coefficient is used to adaptively select the control priority to make the IIDG adapt to different operating scenarios,

Among them: k _g is a preset coefficient, k _d reflects the frequency offset weight, the larger k _d is, the actual control curve is close to Γ ₁ ; when k _a decreases, the actual control curve is close to Γ ₄ , and the whole During the adjustment process, the virtual inertia adopts the minimum value, the sensitivity coefficient corresponding to Γ ₁ to Γ ₄ decreases continuously, and the sensitivity coefficient corresponding to Γ ₄ is zero.

Preferably, the upper and lower limits of the selection range of the virtual inertia constant are obtained from the second-order system damping coefficient, droop coefficient, damping coefficient and control margin of the VSG.

The present invention relates to a device for implementing the above method, including: a priority adaptive adjuster and an offset adaptive adjuster, wherein: the priority adaptive adjuster adaptively selects control between power adjustment and frequency adjustment according to the actual operation scene The priority is to improve the dynamic characteristics of IIDG power and frequency output as a whole, and the offset adaptive regulator performs adaptive adjustment to the virtual inertia according to the frequency output of IIDG to realize a control strategy that takes into account small overshoot and fast response.

technical effect

Compared with the prior art, the present invention realizes the self-adaptive control of the grid-connected inverter type distributed power supply. This strategy takes into account both angular frequency and power output stability control capabilities, and has the characteristics of small overshoot and rapid response, making IIDG in the When the system is disturbed, the output can be quickly stabilized, which can be used to deal with different types of system disturbances. Compared with VSG control and Bang-bang control with fixed inertia, the proposed control strategy takes into account the characteristics of angular frequency and power output, and has the characteristics of small overshoot and rapid response, and the control effect is better.

Description of drawings

Figure 1 is a schematic diagram of the control topology of the VSG-based IIDG;

Fig. 2 is a schematic diagram of active power-frequency control;

Fig. 3 is a schematic flow diagram of the VSG control algorithm;

Figure 4 is a schematic diagram of the change trajectory of the characteristic root of the system in the process of H changing from small to large;

Fig. 5 is the response curve of IIDG output active power offset ΔP;

Fig. 6 is the response curve of the IIDG output frequency offset Δω;

Fig. 7 is the relationship curve between adaptive virtual inertia H and ω;

Fig. 8 is a schematic diagram of double-layer adaptive control;

Fig. 9 is a schematic diagram of the simulation system topology;

Figure 10 is a schematic diagram of the simulation results of grid-connected operation;

In the figure: a is IIDG output, b is virtual inertia;

Figure 11 is a schematic diagram of the simulation results of island operation;

In the figure: a is the IIDG output, b is the virtual inertia.

Detailed ways

As shown in Figure 1, it is the control topology of IIDG based on VSG, in which the PWM signal controls the on-off of the switch tube in the inverter bridge under the drive of the drive circuit, and the output voltage of the bridge arm simulates the internal potential of the synchronous generator. L _f and C _ac are filter inductance and capacitance respectively. After LC filtering, the output voltage of the inverter simulates the terminal voltage of the synchronous generator. Through the disconnection of the public coupling point, IIDG can realize the switching between grid-connected and off-grid operation modes.

其中：P为VSG控制下逆变器端口输出的有功功率，k为阻尼系数，ω为IIDG输出角频率，ω_grid为公共耦合点处角频率，D为有功下垂系数，H为VSG的虚拟惯量常数，2H表示VSG在额定功率指令下从角速度为零的停止状态加速到额定角速度所需要的时间。The frequency control of the IIDG refers to:

Where: P is the active power output by the inverter port under VSG control, k is the damping coefficient, ω is the angular frequency of the IIDG output, ω _grid is the angular frequency at the public coupling point, D is the active droop coefficient, and H is the virtual inertia of the VSG The constant, 2H, represents the time required for the VSG to accelerate from a stop state with an angular velocity of zero to a rated angular velocity under a rated power command.

As shown in Figure 2, it is a schematic diagram of active power-frequency control. When the IIDG works in the grid-connected mode, the frequency control mainly relies on the damping term k(ω-ω _grid ) to track the frequency of the external grid and maintain synchronization with it; when running off-grid, Frequency control uses active power-frequency droop control to simulate the primary frequency modulation function of the power system to provide frequency support for the IIDG system.

For synchronous generators, the moment of inertia marks the rotation characteristics and is related to physical quantities such as the size and mass of the generator. In the VSG control system, since the inertia constant is a virtual control variable, its value can be flexibly selected, and a constant value can be used according to actual needs. Value or function value, the value range is wider than that of synchronous generators, and has better control effect.

当VSG有功功率参考值不变时，建立以公共母线角频率波动为输入、VSG角频率为输出的传递函数：

其中：

δ_s和E_s是功率为P_ref和Q_ref时IIDG的输出电压参量。According to the frequency control of IIDG, the small-signal model of VSG linearized near the given value can be obtained, that is, a system composed of two input quantities and two output quantities, as shown in Figure 3. When the frequency of the common bus is constant at the power frequency, the transfer function between the input and output of VSG active power is established as:

When the VSG active power reference value remains unchanged, a transfer function with the common bus angular frequency fluctuation as the input and the VSG angular frequency as the output is established:

in:

δ _s and E _s are the output voltage parameters of IIDG when the power is Pre _ref and Q _ref .

图4绘制了系统处于欠阻尼状态时，采用不同阻尼系数k下，当H不断增加过程中系统特征根变化轨迹。从图中可见，虚拟惯量常数H不断增加时，系统的特征根绝对值减小，特征根更靠近虚轴，系统稳定裕度逐渐降低。It can be seen from the transfer function expression that the VSG controller is a second-order system, and the characteristic root of the system is:

Fig. 4 plots the change trajectory of the characteristic root of the system in the process of increasing H under different damping coefficient k when the system is in an underdamped state. It can be seen from the figure that when the virtual inertia constant H continues to increase, the absolute value of the characteristic root of the system decreases, the characteristic root is closer to the imaginary axis, and the system stability margin gradually decreases.

The two transfer functions for the VSG control structure can be used to analyze the system response when the IIDG's own active power steps and analyze the system response when the IIDG is disturbed by the frequency of the external system. The following analyzes the IIDG output characteristics separately for power and frequency changes.

其中：

该偏移量的第一次峰值时间t_p和最大超调ΔP(t_p)为：

1] When the active power reference value of IIDG itself changes abruptly, ΔP _ref =α*u(t), where: α represents the magnitude of the mutation, and u(t) is a unit step function. At this time, the IIDG output power deviation is:

in:

The first peak time t _p and the maximum overshoot ΔP(t _p ) for this offset are:

As shown in Figure 5, it is the response curve of IIDG output active power offset ΔP. It can be seen from the figure that as the virtual inertia constant H increases, the overshoot of the IIDG output active power offset ΔP increases continuously, and the fluctuation becomes more severe. That is to say, within this value range, a smaller virtual inertia constant H is more beneficial to active power regulation.

该偏移量的第一次峰值时间

最大超调

2) When the common bus frequency has a small-scale mutation, Δω _grid = α(u(t)-u(t-τ ₀ )), where: α represents the magnitude of the mutation, u(t) is the unit step function, τ ₀ is the sudden change period, at this time the IIDG output frequency deviation is:

The first peak time at this offset

Maximum overshoot

As shown in Figure 6, it is the response curve of the IIDG output frequency offset Δω when the frequency suddenly changes; it can be seen from the figure that as the virtual inertia constant H increases, the overshoot of the IIDG output frequency offset Δω decreases continuously, and the overall fluctuation more flat. That is to say, within this value range, a larger virtual inertia constant H is more beneficial to frequency adjustment.

In different operating scenarios, there are contradictions between the size of the virtual inertia H and the output active power and frequency of the IIDG system. On the one hand, when the IIDG is subjected to a sudden change in the disturbance frequency from the external system, the increase in the virtual inertia constant can reduce the IIDG output frequency offset. On the other hand, when the IIDG's own active power output changes, reducing the virtual inertia constant can reduce the IIDG output active power offset and make the active power regulation more stable.

其中：k_a为自适应控制灵敏因子，H₀为IIDG工作于工频时控制算法采用的虚拟惯量常数，H_h为频率偏移无穷大时对应的虚拟惯量常数；当频率偏移达到1/k_a时，虚拟惯量将为(H₀+H_h)/2，即自适应调节区中值。频率偏移小于1/k_a的区域为响应灵敏区，此区域惯量均较小。频率偏移大于1/k_a的区域为超调平抑区，此区域惯量均较大。Therefore, the double-layer adaptive inertia control method involved in this embodiment can not only adjust the offset adaptively, but also select the control priority adaptively. The relationship curve between the adaptive virtual inertia H and ω is shown in Figure 7. The adaptive control virtual inertia

Among them: k _a is the adaptive control sensitivity factor, H ₀ is the virtual inertia constant used by the control algorithm when IIDG works at industrial frequency, H _h is the corresponding virtual inertia constant when the frequency offset is infinite; when the frequency offset reaches 1/k _a , the virtual inertia will be (H ₀ +H _h )/2, which is the median value of the adaptive adjustment area. The area where the frequency offset is less than 1/k _a is the responsive sensitive area, and the inertia in this area is small. The area where the frequency offset is greater than 1/k _a is the overshoot and stabilization area, and the inertia in this area is relatively large.

Therefore, in Fig. 7, ω=ω _ref ±1/k _a becomes the boundary between the overshoot stable area and the response sensitive area, and k _a can be used to adjust the relative size of the response sensitive area and the overshoot stable area. This parameter characterizes the sensitivity of adaptive control: as k _a increases, the response sensitive area becomes smaller, and the adjustment scale decreases; but as k _a increases, the slope of the curve at the same frequency offset increases, which means that the control system is more efficient. The most sensitive, small state changes can cause parameter adjustments. The sensitivity factors corresponding to the four curves Γ ₁ to Γ ₄ in Figure 7 are continuously decreasing, and the sensitivity factor corresponding to Γ ₄ is zero.

The adaptive adjustment offset refers to: taking _Γ1 as an example, when the IIDG system suffers from frequency disturbance, the frequency operation state deviates from the stable operation point, the control system will enter the response sensitive area, the system responds quickly, and the influence of external fluctuations is suppressed . When the frequency deviation is serious, the control will enter the overshoot and suppression zone. The inertia in this area is large, which greatly reduces the impact of external frequency fluctuations on the IIDG's own frequency output, and the IIDG output frequency will remain flat without large fluctuations. In the limit case, when the frequency offset is infinite, the virtual inertia will be H _h , so H _h is the upper limit of the whole adaptive virtual inertia adjustment. When the IIDG output frequency has no deviation, the virtual inertia constant used by the control algorithm is H ₀ , which is the lower limit of the adaptive virtual inertia constant adjustment. The value of virtual inertia H is always greater than zero during the adjustment process with the change of IIDG output frequency ω, and the control system runs on the asymptote. This makes the control system always have positive damping, and the characteristic root is always on the left side of the imaginary axis, ensuring that the system stability is not damaged during the adjustment process.

其中：k_g为一预设系数，k_d则反映了频率偏移权重，k_d越大，表明输出频率偏移越严重，因此k_a用以自适应选取控制优先级；当输出频率偏移较为严重时，k_a增加，实际控制曲线接近于Γ₁；当输出功率偏移较为严重时，k_a减小，实际控制曲线接近于Γ₄，极端情况下，达到Γ₄，在整个调节过程中虚拟惯量均采用最小值，这可以保证有功功率输出响应快，超调小，动态响应特性良好。The self-adaptive selection control priority refers to: in order to make the IIDG adapt to different operating scenarios, the sensitivity coefficient is adopted

Among them: k _g is a preset coefficient, k _d reflects the frequency offset weight, and the larger k _d is, the more serious the output frequency offset is, so k _a is used to adaptively select the control priority; when the output frequency offset When it is serious, k _a increases, and the actual control curve is close to Γ ₁ ; when the output power deviation is serious, k _a decreases, and the actual control curve is close to Γ ₄ , in extreme cases, it reaches Γ ₄ , and in the whole adjustment process The minimum value of the virtual inertia is used, which can ensure fast response of active power output, small overshoot and good dynamic response characteristics.

To sum up, in actual operation, the control system can not only adjust the output horizontally along the control curve (the x-axis direction in the figure), but also adjust the control priority vertically (the y-axis direction in the figure). The block diagram of the above-mentioned two-layer adaptive control is shown in Fig. 8 .

The virtual inertia constant H is the core parameter in the VSG algorithm, and its selection range directly affects the adjustment time scale of the IIDG system, making the output characteristics of the power grid more diverse. The control system parameters of the VSG are selected in the following manner. According to this series For design reference, the upper and lower limits of the virtual inertia constant selection range H _h , H ₀ can be obtained.

该阻尼系数ζ影响系统响应的性质，为了使系统暂态响应更快达到稳定值，限制系统超调量并使调节时间较小，ζ应取0.4-0.8，即设计参数应满足：

此时，系统处于欠阻尼状态，时间响应呈现衰减振荡。1) Second-order system damping coefficient: Since the VSG control system is a second-order model, its damping coefficient

The damping coefficient ζ affects the nature of the system response. In order to make the system transient response reach a stable value faster, limit the system overshoot and make the adjustment time smaller, ζ should be 0.4-0.8, that is, the design parameters should meet:

At this time, the system is in an underdamped state, and the time response presents decaying oscillations.

2] Droop coefficient: The droop coefficient D is determined by the power grid standard. This design parameter indicates the degree of change in the output active power and reactive power of the inverter every time the frequency changes by 1 Hz and the output voltage amplitude changes by 1 kV. The specific design standards should refer to the provisions in the relevant standards.

3) Damping coefficient: When the IIDG grid-connected operation is stable, ω _ref is equal to ω _grid , the primary frequency modulation term (ω _ref -ω _grid )/D is zero, and the damping controller k(ω-ω _grid ) determines the active power control signal; When the IIDG island is running stably, ω and ω _grid are equal, the damping term k(ω-ω _grid ) is zero, and the primary frequency modulation controller (ω _ref -ω _grid )/D determines the active power control signal; while in actual operation, the IIDG When the system is disturbed, the output of the inverter deviates from the set value. At this time, the damping term and the primary frequency modulation term are both non-zero, and they exist in the active power-frequency control equation at the same time. The adjustment function of the controller should be close to the magnitude of 1/D and k. Only in this way can the corresponding frequency offset be reasonably converted into an active power control signal.

其中：

为传递函数在ω_g处的相位；幅值裕度至少应为6dB，一般设计为10～20dB即：

其中：A(ω_t)为传递函数在ω_t处的幅值。4] Control margin: The characteristic root distribution of the transfer function shows that the VSG control system is a minimum phase system. According to the system design principle: the phase angle margin is at least 30°, and the general design is 40°～60°, that is:

in:

is the phase of the transfer function at ω _g ; the amplitude margin should be at least 6dB, generally designed to be 10~20dB, that is:

Among them: A(ω _t ) is the magnitude of the transfer function at ω _t .

According to the above design principles, the upper and lower limits of the selection range of virtual inertia constants H _h , H ₀ can be obtained.

In this embodiment, a system is built in PSCAD/EMTDC for simulation verification. According to the system topology shown in Figure 9 and the simulation parameters when the VSG-IIDG adopts a double-layer adaptive control strategy is shown in Table 1, the double-layer automatic The upper limit of adaptive control inertia is 1, the lower limit is 0.1, and the k _g is 10.

Table 1 Main parameters of VSG simulation

In order to observe the control effect during grid-connected operation, when the operation reaches 4.2s, the fluctuation of the upper-level distribution network system causes the frequency oscillation of the common bus, and the fluctuation lasts for two power frequency cycles and then disappears. At 6.2s, the power reference value rises from 0.3MW to 0.4MW. Figure 10(a) shows the change of IIDG output frequency under fixed virtual inertia constant and adaptive inertia control, and Figure 10(b) shows the virtual inertia value corresponding to adaptive change.

It can be seen from the figure that after the oscillation occurs, the output frequency of the IIDG is affected and shifts, and finally tends to stabilize and return to the original operating state after oscillation under the action of inertia. It can be seen that compared with the fixed virtual inertia constant, on the one hand, under adaptive control, the frequency and active power overshoot are smaller, and the system output is more stable; at the same time, the disturbance process is extremely fast under adaptive control, the entire oscillation is compressed, and the system can Quick recovery.

In order to observe the effect of the control strategy in island operation (circuit breaker 2 is disconnected), when the system is connected to the grid for 4s, the power reference value drops from 0.4MW to 0.3MW. In addition, the frequency of the common bus changes at 7.2s, and the change lasts for 0.2s. Figure 11 is the simulation result.

In the absence of the frequency support of the distribution network, the IIDG output will deviate after the disturbance, and then finally return to a stable operating state under the regulation of the control system. Compared with the fixed virtual inertia constant, on the one hand, the frequency and active power overshoot under the adaptive control are reduced, and the system output is more stable; at the same time, compared with the large inertia control, the response speed is faster under the adaptive control, and the system can recover quickly .

To sum up, the double-layer adaptive inertial control strategy can take into account the output stability and dynamic response speed, effectively improve the system performance, and strengthen the control effect.

The above specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The scope of protection of the present invention is subject to the claims and is not limited by the above specific implementation. Each implementation within the scope is bound by the invention.

Claims (2)

1. A double-layer self-adaptive inertia control method for an inverter type distributed power supply is characterized in that a relation between a virtual inertia constant of a VSG and an output angular frequency of an IIDG is obtained according to a control topological structure of the IIDG based on the VSG, a small signal model is further established, and the IIDG is adaptive to different operation scenes through a double-layer self-adaptive control strategy of self-adaptive offset adjustment and self-adaptive control priority by simulating an actual operation scene between power adjustment and frequency adjustment through the small signal model;

the relationship between the virtual inertia constant and the IIDG output angular frequency is as follows:

wherein: p is the active power output by the inverter port under VSG control, k is the damping coefficient, omega is the IIDG output angular frequency, omega _grid The angular frequency at the common coupling point, D is an active droop coefficient, H is a virtual inertia constant of VSG, and 2H represents the time required by VSG to accelerate from a stop state with zero angular velocity to the rated angular velocity under the rated power instruction;

when the frequency of the public bus is constant and is kept unchanged as the power frequency, the small signal model establishes a transfer function between VSG active power input and output as follows:

wherein: />

δ _s And E _s Is at a power of P _ref And Q _ref An output voltage parameter of the time IIDG; when the VSG active power reference value is not changed, establishing a transfer function with the common bus angular frequency fluctuation as input and the VSG angular frequency as output: />

The power regulation is that: when the active power reference value of the IIDG is suddenly changed, a smaller virtual inertia constant H is adopted to adjust the active power;

when the IIDG active power reference value per se has sudden change, delta P _ref = α · (t), wherein: α represents the magnitude of the abrupt change, and u (t) is a unit step function, where the IIDG output power deviation is:

wherein: />

Time t of the first peak of the offset _p And a maximum overshoot Δ P (t) _p ) Comprises the following steps: />

The frequency regulation refers to: when the frequency of the public bus is suddenly changed in a small range, the virtual inertia constant H is adaptively adjusted according to the frequency output change of the IIDG;

when the frequency of the common bus has a small-range sudden change, delta omega _grid ＝α(u(t)-u(t-τ ₀ ) Whereinsaid: alpha represents the amplitude of the abrupt change, u (t) is a unit step function, and tau ₀ For the abrupt change period, the IIDG output frequency deviation at this time is:

the first time peak time of the offset->

Maximum overshoot->

When the deviation is small, the control gives priority to the system regulation speed, and the influence of external fluctuation is restrained through quick response after the output overshoot problem is solved; when the deviation is large, the control focuses on stabilizing overshoot, and the response speed of the system is properly reduced;

the self-adaptive adjustment offset is as follows: with gamma ₁ For example, whenWhen the IIDG system suffers frequency disturbance, the frequency running state deviates from a stable running point, the control system enters a response sensitive area, the system responds quickly, the influence of external fluctuation is restrained, when the frequency deviation is serious, the control system enters an overshoot area, the inertia of the area is large, the influence of the external frequency fluctuation on the frequency output of the IIDG is greatly reduced, the IIDG output frequency is kept smooth, large fluctuation is avoided, and under the limit condition, when the frequency deviation is infinite, the virtual inertia is H _h Thus H _h Is the upper limit of the whole self-adaptive virtual inertia adjustment, and when the IIDG output frequency has no deviation, the virtual inertia constant adopted by the control algorithm is H ₀ The value of the virtual inertia H is always larger than zero in the adjusting process along with the change of the IIDG output frequency omega, the control system runs above an asymptote, positive damping exists in the control system all the time, and the characteristic root is always positioned on the left side of a virtual axis, so that the stability of the system is not damaged in the adjusting process;

the self-adaptive control priority is characterized in that the IIDG adapts to different operating scenes by adopting a sensitivity coefficient to self-adaptively select the control priority,

wherein: k is a radical of formula _g Is a predetermined coefficient, k _d Then the frequency offset weight, k, is reflected _d The larger the actual control curve approaches Γ ₁ (ii) a When k is _a The actual control curve is reduced to approach gamma ₄ Then the virtual inertia in the whole adjustment process takes the minimum value, Γ ₁ To gamma ₄ Corresponding sensitivity coefficient is continuously reduced, gamma ₄ The corresponding sensitivity coefficient is zero;

and solving the upper limit and the lower limit of the virtual inertia constant selection range through the second-order system damping coefficient, the droop coefficient, the damping coefficient and the control margin of the VSG.

2. An apparatus for implementing the method of claim 1, comprising: priority adaptive adjuster, offset adaptive adjuster, wherein: the priority self-adaptive regulator self-adaptively selects a control priority between power regulation and frequency regulation according to an actual operation scene so as to integrally improve the dynamic characteristics of IIDG power and frequency output, and the offset self-adaptive regulator performs self-adaptive regulation on the virtual inertia according to the frequency output of the IIDG, so that a control strategy which is small in overshoot and high in response speed is realized.

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