CN106253305A - A kind of full-separate isolated island powerless control method for distributed power source - Google Patents

Abstract

The invention discloses a kind of full-separate isolated island powerless control method for distributed power source.Distributed power source to Q V droop control, is controlled by first, second output voltage control mode simultaneously, after decoupling first, second control output voltage variable quantity, be added to obtain output voltage control amount and then carry out Control of Voltage；Distributed power source to V Q droop control, controlled by first, second target voltage control mode simultaneously, first, second control target voltage variable quantity is obtained after decoupling, it is calculated PCC point target magnitude of voltage, it is calculated idle feedforward value and idle value of feedback, is added and obtains Reactive Power Control amount and then carry out Reactive Power Control.The present invention can be applied to the reactive power of distributed power source in isolated island micro-capacitance sensor and share mutual with plug and play and irrelevant information, greatly reducing complexity and the cost of system, median filter of the present invention is important role in terms of promoting microgrid dynamic property and maintaining system stability.

Description

A kind of full-separate isolated island powerless control method for distributed power source

Technical field

The present invention relates to the control method of a kind of micro-capacitance sensor, especially relate to a kind of full-separate for distributed power source Isolated island powerless control method.

Background technology

Distributed power generation refers to be directly arranged at power distribution network or be distributed in the power generating equipment near load, it is possible to economical, high Imitate, reliably generate electricity.Distributed electrical source position is flexible, dispersion, can be the most standby with bulk power grid, has shared defeated to a certain extent Electrical network from power plant to user the remote and function of bulk power transmission.Although distributed power source advantages, but distributed power source Being a uncontrollable power supply for bulk power grid, bulk power grid also tends to limit or isolation distributed power source.Big in order to coordinate Electrical network and the contradiction of distributed power source, also been proposed the concept of micro-capacitance sensor.Micro-capacitance sensor be one by load and common group of micro battery The system become, it can provide electric energy and heat simultaneously；Micro battery is responsible for energy conversion by power electronic devices, and provides required Control；Bulk power grid is shown as single controlled cell, user is then shown as customizable power supply.

At present, micro-capacitance sensor can be operated in also net state and lonely net state.Under lonely net state, distributed power source is typically adopted Load is reasonably shared by the method for droop control.And in droop control, frequency can be relatively simply passed through in burden with power Sagging mode distributes to each distributed power source, because the frequency change of micro-grid system is continuous print in steady-state process.But It is that, owing to each distributed power source machine terminal impedance is the most identical, the output voltage of each distributed power source is also not necessarily phase Deng.Thus, the droop control of reactive power and voltage is difficult to obtain good effect.Situation in load or burden without work big ups and downs Under, the voltage of PCC point is also difficult to tend towards stability rapidly.

For solving a difficult problem for the droop control of current reactive power and voltage, scholar is had to propose to introduce the general of virtual impedance Read, weaken the impact of machine terminal impedance, but this method easily affects the quality of voltage of microgrid；Also scholar is had to pass through to microgrid In each distributed power source inject a kind of harmonic voltage signal containing reactive power information reasonably share load or burden without work, but It it is the distortion that is likely to cause distributed power source machine end output voltage of this method.It addition, current research is concentrated mainly on and adopts On distributed power source with reactive power-voltage (Q-V) droop control, but have ignored employing voltage-reactive power (V-Q) sagging The distributed power source controlled, and rarely achievement in research can solve the problem that the recovery problem of PCC point voltage when load or burden without work fluctuates.

Summary of the invention

For solving the problems referred to above, the present invention proposes a kind of idle controlling party of full-separate isolated island for distributed power source Method, simultaneously to using reactive power-voltage (Q-V) droop control and using the distribution of voltage-reactive power (V-Q) droop control Formula power supply is controlled, and the reactive power being applied to distributed power source under lonely net state is shared and plug and play.

Technical scheme employing following steps:

The present invention is directed to use the distributed power source of Q-V droop control or use the distributed power source of V-Q droop control, Being controlled obtaining two variable quantities by two kinds of voltage control modes, two variable quantities are added or process further simultaneously To reference value, it is applied on distributed power source carry out the control of voltage or power.

If for the distributed power source of employing Q-V droop control, each distributed power source is simultaneously by the first output voltage Control mode and the second output voltage control mode are respectively controlled, more respectively by the first low pass filter and the second low pass Wave filter decouples, and obtains the first control output voltage variable quantity V after decoupling_pri(Q_i) and the second control output voltage change Amount V_sec(α,V_PCC,cal), use below equation to control output voltage variable quantity V by first_pri(Q_i), second control output voltage become Change amount V_sec(α,V_PCC,cal) be added obtain output voltage reference value V_i,ref, and then distributed power source is carried out Control of Voltage；

V_i,ref=V_pri(Q_i)+V_sec(α,V_PCC,cal)；

If for the distributed power source of employing V-Q droop control, each distributed power source passes through first object the most simultaneously Voltage control mode and the second target voltage control mode are respectively controlled, then are carried out by the first and second low pass filters Decoupling, obtains the first control target voltage variable quantity V after decoupling_pri,obj(Q_i) and the second control target voltage variable quantity V_sec,obj (α,V_PCC,obj), use below equation to control target voltage variable quantity V by first_pri,obj(Q_i) and the second control target voltage change Change amount V_sec,obj(α,V_PCC,obj) be added obtain target voltage controlled quentity controlled variable V_i,obj, and obtain PCC point (public company by Load flow calculation Contact) target voltage amplitude V_PCC,obj；

V_i,obj=V_pri,obj(Q_i)+V_sec,obj(α,V_PCC,obj)

Then for each distributed power source, simultaneously by according to target voltage controlled quentity controlled variable V_i,objBefore the voltage-tracing carried out Feedback controls and according to PCC point target voltage magnitude V_PCC,objThe voltage-tracing feedback control carried out is respectively controlled, and obtains electricity Pressure follows the tracks of feedforward valueWith voltage-tracing value of feedbackUse below equation that both additions obtain reactive power output Reference value Q_i,ref, and then distributed power source is carried out the control of power:

$Q_{i,ref}=Q_{i,ref}^{back}+Q_{i,ref}^{forward}.$

Described first output voltage control mode uses below equation to be calculated the first control output voltage variable quantity V_pri (Q_i):

$V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, V^*For the output voltage reference value of distributed power source, Q_iFor the reactive power output valve of distributed power source, n is The sagging slope of standard, n_iIt is the sagging slope of i-th distributed power source, n=(V_max-V_min)/S_i, S_iIt is regarding of distributed power source At power capacity, V_maxAnd V_minIt is respectively the output voltage upper and lower limit of distributed power source, T₁It it is the time of the first low pass filter Constant, s is frequency domain variable.

The sagging slope n of i-th described distributed power source_iConcrete employing below equation is calculated:

$\left\{\begin{array}{c}{n}_i=n_k+\frac{1}{V_{PCC,ref}}(X_k-X_i),i\≠k\\ n_k=n\end{array}\right.$

Wherein, X_iIt is the outfan reactance of i-th distributed power source, X_kFor kth platform distributed power source outfan reactance and It is the maximum in microgrid in the outfan reactance of all distributed power sources, n_iIt is the sagging slope of i-th distributed power source, n_k For kth platform distributed power source sagging slope and be the sagging slope of standard, i.e. n_k=n, V_PCC,refFor PCC point voltage reference value.

Described second output voltage control mode uses below equation to be calculated the second control output voltage variable quantity V_sec (α,V_PCC,cal):

$V_{\sec }(\mathrm{\α},V_{PCC,cal})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,cal})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,calFor PCC point virtual voltage amplitude, V_PCC,refFor PCC point voltage reference value, T₂ Being the time constant of the second low pass filter, s is frequency domain variable.

Described first object voltage control mode uses below equation to be calculated the first control target voltage variable quantity V_pri,obj(Q_i):

$V_{pri,obj}\left(Q_i\right)=V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, V^*For the output voltage reference value of distributed power source, Q_iFor the reactive power output valve of distributed power source, n is The sagging slope of standard, n_iIt is the sagging slope of i-th distributed power source, n=(V_max-V_min)/S_i, S_iIt is regarding of distributed power source At power capacity, V_maxAnd V_minIt is respectively the output voltage upper and lower limit of distributed power source, T₁It it is the time of the first low pass filter Constant, s is frequency domain variable.

Described second target voltage control mode uses below equation to be calculated the second control target voltage variable quantity V_sec,obj(α,V_PCC,obj):

$V_{\sec ,obj}(\mathrm{\α},V_{PCC,obj})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,obj})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,objFor PCC point target voltage magnitude, V_PCC,refFor PCC point voltage reference value, T₂ Being the time constant of the second low pass filter, s is frequency domain variable.

The described voltage-tracing feedforward uses below equation to be calculated voltage-tracing feedforward value

$Q_{i,ref}^{forward}=S_i-\frac{1}{n}(V_{i,obj}-V_{min})$

Wherein, n is the sagging slope of standard, n=(V_max-V_min)/S_i, S_iIt is the apparent energy capacity of distributed power source, V_max And V_minIt is respectively the output voltage upper and lower limit of distributed power source, V_i,objRepresent target voltage controlled quentity controlled variable.

Described voltage-tracing feedback control uses below equation to be calculated voltage-tracing value of feedback

$Q_{i,ref}^{back}=K_P(V_{PCC,obj}-V_{PCC,cal})+K_I\∫(V_{PCC,obj}-V_{PCC,cal})dt$

Wherein, K_PFor PI proportional component coefficient, K_IFor PI integral element coefficient, V_PCC,objRepresent PCC point target voltage amplitude Value, V_PCC,calFor PCC point virtual voltage amplitude.

What the present invention had has the advantages that:

The present invention can be applied to the reactive power of distributed power source in isolated island micro-capacitance sensor and share and plug and play and not Need information mutual, greatly reduce complexity and the cost of system, and PCC point can be solved when load or burden without work fluctuates Voltage resumption problem.In the present invention, wave filter has important in terms of promoting microgrid dynamic property and maintaining system stability Effect.

The present invention can complete nothing in local distributed power source (Distributed Generator, referred to as DG) Merit power one secondary control, linear quadratic control, can not by Centralized Controller with communicate in the case of, System Reactive Power load is divided Stand is to each distributed power source, and makes each distributed power source reasonably adjust machine end output voltage, and then makes PCC point electricity Pressure tends towards stability；Two low pass filters therein are in order to decouple the dynamic characteristic of distributed power source, and improve system Performance.

The present invention can without the help of information mutual when, be applied to use reactive power-voltage (Q-V) sagging control System and the distributed power source of employing voltage-reactive power (V-Q) droop control, it is also possible to be extended to other application sides of micro-capacitance sensor Face.

Accompanying drawing explanation

Fig. 1 is the control method schematic diagram of the distributed power source using Q-V droop control in the inventive method.

Fig. 2 is the control method schematic diagram of the distributed power source using V-Q droop control in the inventive method.

Fig. 3 is the distributed power source equivalent model figure in tradition droop control.

Fig. 4 is the principle schematic improving sagging Slope Method in the inventive method.

Fig. 5 is the micro-capacitance sensor illustraton of model of the simulating, verifying of the present invention.

Fig. 6 (a) be the present invention simulating, verifying in microgrid reactive power load fluctuation time PCC point voltage change curve.

Fig. 6 (b) be the present invention simulating, verifying in microgrid reactive power load fluctuation time each distributed power source export idle merit The change curve of rate.

Fig. 7 (a) be the present invention simulating, verifying in PCC point voltage reference value change time PCC point voltage change curve

Fig. 7 (b) be the present invention simulating, verifying in PCC point voltage reference value change time each distributed power source output nothing The change curve of merit power

Fig. 8 (a) be the present invention simulating, verifying in switching distributed power source DG2 time PCC point voltage change curve

Fig. 8 (b) be the present invention simulating, verifying in switching distributed power source DG2 time each distributed power source output idle The change curve of power

In figure: the DG1 in all figures, DG2, DG3, DG4 are four distributed power sources of same group.

Detailed description of the invention

Below in conjunction with the accompanying drawings and the present invention is described in further detail by specific embodiment.

The inventive method uses different idle control modes to carry out for the distributed power source of two kinds of different droop controls.

1) as it is shown in figure 1, for using the distributed power source of Q-V droop control, each distributed power source is simultaneously by the One output voltage control mode, the second output voltage control mode are controlled, and respectively obtain the first control output voltage change Amount V_pri(Q_i), second control output voltage variable quantity V_sec(α,V_PCC,cal), and solved by the first and second low pass filters Coupling；Formula is used to control output voltage variable quantity V by first_pri(Q_i), second control output voltage variable quantity V_sec(α,V_PCC,cal) Addition obtains output voltage reference value V_i,ref, and then distributed power source is carried out Control of Voltage；

V_i,ref=V_pri(Q_i)+V_sec(α,V_PCC,cal)

Step 1) in the first output voltage control mode use below equation be calculated first control output voltage become Change amount V_pri(Q_i):

$V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, V^*For the output voltage reference value of distributed power source, V_maxAnd V_minIt is respectively the output electricity of distributed power source Pressure upper and lower limit, S_iIt is the apparent energy capacity of distributed power source, Q_iFor the reactive power output valve of distributed power source, n is standard Sagging slope, n=(V_max-V_min)/S_i, T₁Being the time constant of the first low pass filter, s is frequency domain variable.

First controls output voltage variable quantity V_priIn n_iEmploying below equation is calculated:

$\left\{\begin{array}{c}{n}_i=n_k+\frac{1}{V_{PCC,ref}}(X_k-X_i),i\≠k\\ n_k=n\end{array}\right.$

Wherein, X_iIt is the outfan reactance of i-th distributed power source, X_kFor kth platform distributed power source outfan reactance and It is the maximum in microgrid in the outfan reactance of all distributed power sources, n_iIt is the sagging slope of i-th distributed power source, n_k For kth platform distributed power source sagging slope and be standard sagging slope (i.e. n_k=n), V_PCC,refVoltage Reference for PCC point Value.

Second output voltage control mode uses below equation to be calculated the second control output voltage variable quantity V_sec(α, V_PCC,cal):

$V_{\sec }(\mathrm{\α},V_{PCC,cal})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,cal})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,calFor PCC point virtual voltage amplitude, T₂The time being the second low pass filter is normal Number, s is frequency domain variable.

2) as in figure 2 it is shown, for using the distributed power source of V-Q droop control, each distributed power source first passes through the One target voltage control mode, the second target voltage control mode are controlled, and respectively obtain the first control target voltage change Amount V_pri,obj(Q_i), second control target voltage variable quantity V_sec,obj(α,V_PCC,obj), and by the first and second low pass filters Decouple；By V_pri,obj(Q_i) and V_sec,obj(α,V_PCC,obj) be added obtain target voltage controlled quentity controlled variable V_i,obj, and by trend meter Calculation obtains PCC point target voltage magnitude V_PCC,obj；Then each distributed power source is simultaneously by the voltage-tracing feedforward and electricity Pressure is followed the tracks of feedback control and is controlled, and respectively obtains voltage-tracing feedforward valueWith voltage-tracing value of feedbackAnd by two Person is added reference value Q obtaining reactive power output_i,ref, and then distributed power source is controlled.Above-mentioned relation equation below Represent.

$\left\{\begin{array}{c}{V}_{i,obj}=V_{pri,obj}\left(Q_i\right)+V_{\sec ,obj}(\mathrm{\α},V_{PCC,obj})\\ Q_{i,ref}=Q_{i,ref}^{back}+Q_{i,ref}^{forward}\end{array}\right.$

First object voltage control mode uses below equation to be calculated the first control target voltage variable quantity V_pri,obj (Q_i):

$V_{pri,obj}\left(Q_i\right)=V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, first controls target voltage variable quantity V_pri,obj(Q_i) control output voltage variable quantity V with first_pri(Q_i) meter Calculation method is identical, and parameter meaning is the most identical.

Second target voltage control mode uses below equation to be calculated the second control target voltage variable quantity V_sec,obj (α,V_PCC,obj):

$V_{\sec ,obj}(\mathrm{\α},V_{PCC,obj})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,obj})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,objFor PCC point target voltage magnitude, T₂The time being the second low pass filter is normal Number, s is frequency domain variable.

The voltage-tracing feedforward uses below equation to be calculated voltage-tracing feedforward value

$Q_{i,ref}^{forward}=S_i-\frac{1}{n}(V_{i,obj}-V_{min})$

Voltage-tracing feedback control uses below equation to be calculated voltage-tracing value of feedback

$Q_{i,ref}^{back}=K_P(V_{PCC,obj}-V_{PCC,cal})+K_I\∫(V_{PCC,obj}-V_{PCC,cal})dt$

Wherein, K_PFor PI proportional component coefficient, K_IFor PI integral element coefficient.

The present invention designs for distributed power source (DG) all of in micro-capacitance sensor, and each distributed power source (DG) has Corresponding control method.Each distributed power source is all carried out by an integrated local control method.The present invention is mainly by two Individual part forms: for the control of distributed power source sagging for employing Q-V, for the control using distributed power source sagging for V-Q System.Processed by decoupling, micro-grid system dynamic characteristic be similar when using traditional droop control method, therefore adopt By the system after control of the present invention, there is preferable stable state and dynamic property.

The design principle of the present invention is as follows:

In tradition droop control, the equivalent model figure of distributed power source is as shown in Figure 3.Wherein, L_f,iAnd C_f,iIt it is i-th The inductance of the LC wave filter of distributed power source and capacitance parameter, L_feeder,iIt is the feeder line inductance of i-th distributed power source, L_T,iIt is I-th distributed power source connected transformator T_iInternal inductance, V_i∠δ_iIt is the set end voltage of i-th distributed power source, V_PCC ∠ 0 ° is the voltage of PCC point.Line impedance owing to line resistance is negligible, between i-th distributed power source and PCC point X_iCan represent by below equation:

X_i=X_feeder,i+X_T,i=ω (L_feeder.i+L_T,i)

Wherein, X_feeder,iRepresent the feeder line reactance between i-th distributed power source and PCC point, X_T,iRepresent i-th distributed The inside reactance of connected transformator between power supply and PCC point.

Tradition droop control then can represent by below equation:

$\left\{\begin{array}{c}{\mathrm{\ω}}_i={\mathrm{\ω}}^{*}-m_i{P}_i\\ V_i=V^{*}-n_i{Q}_i\end{array}\right.$

Wherein, ω_iIt is the output angle frequency of i-th distributed power source, V_iIt it is the set end voltage width of i-th distributed power source Value, ω^*And V^*It is respectively angular frequency and the reference value of set end voltage amplitude, P_iIt it is the output wattful power of i-th distributed power source Rate, Q_iIt is the output reactive power of i-th distributed power source, m_iIt is the meritorious sagging coefficient of i-th distributed power source, n_iIt is i-th The idle sagging coefficient of platform distributed power source.

It addition, as it is shown on figure 3, set end voltage amplitude V of i-th distributed power source_iCan be by PCC point voltage amplitude V_PCCMeter Obtain:

$V_i=V_{PCC}+\frac{Q_i{X}_i}{V_{PCC}}---\left(12\right)$

In conjunction with both the above formula, the calculation of the output reactive power of available i-th distributed power source:

$Q_i=\frac{V_{PCC}(V^{*}-V_{PCC})}{X_i+V_{PCC}{n}_i}$

When microgrid has two distributed power source DG1 and DG2, and the equal S of apparent energy capacity of distributed power source₁= S₂, then the difference of two distributed power source output reactive powers is:

${\mathrm{\ΔQ}}_{err}=\frac{Q_1-Q_2}{Q_1}=\frac{(X_2-X_1)+V_{PCC}(n_2-n_1)}{X_2+V_{PCC}{n}_2}$

To make the difference of two distributed power source output reactive powers be zero i.e. Δ Q_err=0, then it must is fulfilled for:

$n_2=n_1+\frac{1}{V_{PCC}}(X_1-X_2)$

When two distributed power sources that apparent energy is identical use tradition droop control, if each distributed power source is defeated Go out reactive power equal, then control effect best；But as shown from the above formula, when each distributed power source feeder line inductance not Meanwhile, output reactive power also can be unequal.The inventive method reduces the difference of two distributed power source output reactive powers Principle as shown in Figure 4: assume X₁>X₂, increase the idle sagging coefficient n of DG2₂Can reduce by two distributed power source output nothings The difference of merit power.

The specific embodiment of the present invention is as follows:

Setting up a typical isolated island exchange micro-capacitance sensor in Matlab/Simulink software, micro-capacitance sensor includes four 1MW Distributed generator (DG1, DG2, DG3, DG4), a firm demand and two variable loads, as shown in Figure 5.Wherein, DG1 Use Q-V droop control with DG2, and DG3 and DG4 uses V-Q droop control.Other parameters of system are as shown in Fig. 5 and Biao 1:

Table 1 components of system as directed parameter value

In simulated example, devise three kinds of operating modes and carry out simulating, verifying:

(1) initial load or burden without work be 1.2MVar, PCC point voltage reference value be 0.91p.u..As t=20s, system is total Load or burden without work rises to 1.5MVar；Working as t=30s, the total load or burden without work of system rises to 1.8Mvar.Emulating image is as shown in Figure 6.

PCC point voltage change curve when Fig. 6 (a) is microgrid reactive power load fluctuation, Fig. 6 (b) is microgrid reactive power load fluctuation Time each distributed power source output reactive power change curve.From Fig. 6 (a), when System Reactive Power load rises, PCC Point voltage amplitude has a transient process the shortest, and promptly converges to PCC point voltage reference value.Whole transient process Voltage magnitude deviation is less than 0.001p.u..And from Fig. 6 (b), when load or burden without work fluctuates, the inventive method can make The deviation of the output reactive power of each distributed power source is reduced to zero.

(2) initial load or burden without work is 1.2MVar, works as t=25s, PCC point voltage reference value and is risen to by 0.91p.u. 0.95p.u..According to formula (4), the idle sagging coefficient of four distributed power sources changes the most accordingly, parameter value such as table 2 institute Show.Emulating image is as shown in Figure 7.

Table 2V_PCC,refThe idle sagging coefficient of each distributed power source when=0.95

Parameter	Numerical value
		The idle sagging coefficient n of DG11	0.2
The idle sagging coefficient n of DG22	0.367
		The idle sagging coefficient n of DG33	0.326
The idle sagging coefficient n of DG44	0.262

Fig. 7 (a) is the PCC point voltage change curve during change of PCC point voltage reference value, and Fig. 7 (b) is PCC point voltage ginseng Examine the change curve of each distributed power source output reactive power during value change.From Fig. 7 (a), when PCC point voltage reference When value rises to 0.95p.u., PCC point voltage amplitude can converge to rapidly new voltage reference value and voltage magnitude deviation Less than 0.001p.u..And in Fig. 7 (b), the output reactive power of each distributed power source can be along with voltage reference value Change is reacted rapidly, and converges on same reactive power value.

(3) initial load or burden without work be 1.2MVar, PCC point voltage reference value be 0.91p.u..As t=15s, DG2 exits Micro-grid system；As t=44s, DG2 again puts into micro-grid system and runs.Emulating image is as shown in Figure 8.

Fig. 8 (a) is PCC point voltage change curve during switching distributed power source DG2, and Fig. 8 (b) is switching distributed power source The change curve of each distributed power source output reactive power during DG2.In Fig. 8 (a), when DG2 exits micro-grid system, PCC point voltage amplitude has a transient process the shortest, and promptly converges to PCC point voltage reference value.And by Fig. 8 (b) Understanding, after DG2 exits micro-grid system, the output reactive power of other three distributed power sources can rise rapidly and all converge on New steady-state value, the output reactive power of DG2 declines the most rapidly and also can restrain and keep stable；And when DG2 throws again After entering micro-grid system operation, the output reactive power of four distributed power sources can promptly converge on again DG2 and exit microgrid system Steady-state value before system.

It must be noted that the new type of control method that the present invention proposes disclosure satisfy that employing Q-V droop control and uses V-Q The control requirement of the distributed power source of droop control.In the case of not communication and central control system, the control of the present invention Method can preferably solve microgrid reactive power load and share out equally and PCC point voltage recovery problem, makes system stable operation.The present invention Control method make system have preferable stable state and dynamic property, be a feasible control method.

Above-mentioned detailed description of the invention is used for illustrating the present invention rather than limiting the invention, the present invention's In spirit and scope of the claims, any modifications and changes that the present invention is made, both fall within the protection model of the present invention Enclose.

Claims (8)

1. the full-separate isolated island powerless control method for distributed power source, it is characterised in that comprise the following steps:

If for the distributed power source of employing Q-V droop control, each distributed power source is simultaneously by the first output voltage control Mode and the second output voltage control mode are respectively controlled, more respectively by the first low pass filter and the second low-pass filtering Device decouples, and obtains the first control output voltage variable quantity V after decoupling_pri(Q_i) and the second control output voltage variable quantity V_sec (α,V_PCC,cal), use below equation to control output voltage variable quantity V by first_pri(Q_i), second control output voltage variable quantity V_sec(α,V_PCC,cal) be added obtain output voltage reference value V_i,ref, and then distributed power source is carried out Control of Voltage；

V_i,ref=V_pri(Q_i)+V_sec(α,V_PCC,cal)；

If for the distributed power source of employing V-Q droop control, each distributed power source is the most simultaneously by first object voltage Control mode and the second target voltage control mode are respectively controlled, then are solved by the first and second low pass filters Coupling, obtains the first control target voltage variable quantity V after decoupling_pri,obj(Q_i) and the second control target voltage variable quantity V_sec,obj(α, V_PCC,obj), use below equation to control target voltage variable quantity V by first_pri,obj(Q_i) and the second control target voltage variable quantity V_sec,obj(α,V_PCC,obj) be added obtain target voltage controlled quentity controlled variable V_i,obj, and obtain PCC point target voltage amplitude by Load flow calculation Value V_PCC,obj；

V_i,obj=V_pri,obj(Q_i)+V_sec,obj(α,V_PCC,obj)

Then for each distributed power source, simultaneously by according to target voltage controlled quentity controlled variable V_i,objThe voltage-tracing feedforward control carried out Make and according to PCC point target voltage magnitude V_PCC,objThe voltage-tracing feedback control carried out is respectively controlled, obtain voltage with Track feedforward valueWith voltage-tracing value of feedbackUse below equation that both additions obtain the ginseng of reactive power output Examine value Q_i,ref, and then distributed power source is carried out the control of power:

$Q_{i,ref}=Q_{i,ref}^{back}+Q_{i,ref}^{forward}.$

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: described first output voltage control mode uses below equation to be calculated the first control output voltage variable quantity V_pri (Q_i):

$V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, V^*For the output voltage reference value of distributed power source, Q_iFor the reactive power output valve of distributed power source, n is standard Sagging slope, n_iIt is the sagging slope of i-th distributed power source, n=(V_max-V_min)/S_i, S_iIt it is the apparent merit of distributed power source Rate capacity, V_maxAnd V_minIt is respectively the output voltage upper and lower limit of distributed power source, T₁The time being the first low pass filter is normal Number, s is frequency domain variable.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 2, its feature It is: the sagging slope n of i-th described distributed power source_iConcrete employing below equation is calculated:

$\left\{\begin{array}{c}{n}_i=n_k+\frac{1}{V_{PCC,ref}}(X_k-X_i),i\≠k\\ n_k=n\end{array}\right.$

Wherein, X_iIt is the outfan reactance of i-th distributed power source, X_kFor kth platform distributed power source outfan reactance and be micro- Maximum in the outfan reactance of all distributed power sources, n in net_iIt is the sagging slope of i-th distributed power source, n_kFor kth The sagging slope of platform distributed power source and be the sagging slope of standard, i.e. n_k=n, V_PCC,refFor PCC point voltage reference value.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: described second output voltage control mode uses below equation to be calculated the second control output voltage variable quantity V_sec(α, V_PCC,cal):

$V_{\sec }(\mathrm{\α},V_{PCC,cal})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,cal})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,calFor PCC point virtual voltage amplitude, V_PCC,refFor PCC point voltage reference value, T₂It is The time constant of two low pass filters, s is frequency domain variable.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: described first object voltage control mode uses below equation to be calculated the first control target voltage variable quantity V_pri,obj (Q_i):

$V_{pri,obj}\left(Q_i\right)=V_{pri}\left(Q_i\right)=(V^{*}-{\mathrm{nQ}}_i)+\[(V^{*}-n_i{Q}_i)-(V^{*}-{\mathrm{nQ}}_i)\]\frac{1}{1+T_{1}s}$

Wherein, V^*For the output voltage reference value of distributed power source, Q_iFor the reactive power output valve of distributed power source, n is standard Sagging slope, n_iIt is the sagging slope of i-th distributed power source, n=(V_max-V_min)/S_i, S_iIt it is the apparent merit of distributed power source Rate capacity, V_maxAnd V_minIt is respectively the output voltage upper and lower limit of distributed power source, T₁The time being the first low pass filter is normal Number, s is frequency domain variable.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: described second target voltage control mode uses below equation to be calculated the second control target voltage variable quantity V_sec,obj (α,V_PCC,obj):

$V_{\sec ,obj}(\mathrm{\α},V_{PCC,obj})=\mathrm{\α}(V_{PCC,ref}-V_{PCC,obj})\frac{1}{1+T_{2}s}$

Wherein, α is gain coefficient, V_PCC,objFor PCC point target voltage magnitude, V_PCC,refFor PCC point voltage reference value, T₂It is The time constant of two low pass filters, s is frequency domain variable.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: the described voltage-tracing feedforward uses below equation to be calculated voltage-tracing feedforward value

$Q_{i,ref}^{forward}=S_i-\frac{1}{n}(V_{i,obj}-V_{\min })$

Wherein, n is the sagging slope of standard, n=(V_max-V_min)/S_i, S_iIt is the apparent energy capacity of distributed power source, V_maxAnd V_min It is respectively the output voltage upper and lower limit of distributed power source, V_i,objRepresent target voltage controlled quentity controlled variable.

A kind of full-separate isolated island powerless control method for distributed power source the most according to claim 1, its feature It is: described voltage-tracing feedback control uses below equation to be calculated voltage-tracing value of feedback

$Q_{i,ref}^{back}=K_P(V_{PCC,obj}-V_{PCC,cal})+K_I\∫(V_{PCC,obj}-V_{PCC,cal})dt$

Wherein, K_PFor PI proportional component coefficient, K_IFor PI integral element coefficient, V_PCC,objRepresent PCC point target voltage magnitude, V_PCC,calFor PCC point virtual voltage amplitude.