CN106253338A - A kind of micro-capacitance sensor stable control method based on adaptive sliding-mode observer - Google Patents

Abstract

The invention discloses a kind of micro-capacitance sensor stable control method based on self adaptation total-sliding-mode control, step is: (1) being incorporated into the power networks and operation characteristic during islet operation for micro-capacitance sensor, sets up the mathematical model of inverter system respectively；(2) control to combine with sliding formwork by Self Adaptive Control, build respectively and be incorporated into the power networks and the adaptive sliding-mode observer model of inverter system during islet operation；(3) the adaptive sliding-mode observer model of inverter system is acted on pulse width modulation (PWM), three-phase inverter is controlled, thus realize the three-phase inverter adaptive sliding-mode observer that micro-capacitance sensor is stable.Present invention micro-capacitance sensor based on self adaptation total-sliding-mode control stable control method, ensure that micro-capacitance sensor stability under different operational modes: effectively suppress when micro-grid connection is run micro-capacitance sensor to exchange power swing with main electrical network, reach micro-capacitance sensor controlled with main electrical network exchange power；Micro-capacitance sensor seamless switching between 2 kinds of operational modes can be realized.

Description

A kind of micro-capacitance sensor stable control method based on adaptive sliding-mode observer

Technical field

The invention belongs to intelligent power grid technology field, particularly realize the three-phase inverter adaptive sliding mode that micro-capacitance sensor is stable Control method.

Background technology

Distributed power generation (distributed generation, DG) is little with its investment, clean environment firendly, power supply reliability high With the generation mode advantage such as flexibly, increasingly paid close attention to by people.DG and load are connected and composed micro-capacitance sensor, and with this shape Formula enters bulk power grid and supports each other with bulk power grid, is the most effective mode playing DG system effectiveness.Micro-grid connection (generally distribution Net) run, and between main electrical network, active power and reactive power can exchange flexibly.If main grid collapses, micro-capacitance sensor is rapid With major network off-the-line, run on island mode, it is ensured that the power supply of important load.Main power system restoration normally rear micro-capacitance sensor can join again Net, reenters the pattern of being incorporated into the power networks.

Microgrid stabilization controller must have stronger anti-interference and voltage control capability, has after disturbance occurs in electrical network Dynamic response quickly.Owing to three-phase PWM inverter model is a typical non-linear multi-input multi-output system, in model Containing state variable and the product of control variable, and there is coupling between state variable, conventional control strategy is difficult to meet output The requirements such as zero steady-state error, fast dynamic response, input current abnormality are little.Additionally, due to small-signal is it is assumed that conventional linear and non- Linear control strategies, it is impossible to be applicable to large signal operation condition.When there is big transient changing, the behavior of inverter cannot be filled Reflect with dividing.

As a kind of control method in design alternative with high degree of flexibility, sliding formwork controls than other nonlinear Control Method is more easily implemented.Sliding formwork control major advantage be can ensure that system at Parameter uncertainties, there is external interference situation Under stability and robustness.Zhao Kuiyin et al. utilizes sliding formwork to control to stablize the DC voltage of three-phase commutation bridge, guarantee system Unity power factor.Sliding formwork is controlled to be used for single-phase inverter, for grid-connected, 2 kinds of the isolated island of inverter by Rong J W et al. The method of operation separately designs control method.Fernando S J et al. uses sliding formwork control design case Voltage loop, and control system has Have that response is fast, strong robustness, to external world interference and parameter perturbation have the advantages such as invariance；But owing to electric current loop uses stagnant ring control System, there is output voltage has static error and the unfixed shortcoming of switching frequency.In actual control system, due to systematic parameter The impact of the factors such as the restriction of change, external disturbance and detection technique, is generally difficult to obtain the accurate model of control object, and Matching condition is often difficult to meet, and makes tradition sliding formwork control to be unable to reach desired qualities.

As the above analysis, for essence to the mathematical model of inverter system of the prior art of three-phase converter Exactness requires height, does not considers the impact of thinking on control performance of real system parameter uncertainty and external interference problem, thus Shandong Rod is not strong, does not meets the requirement of actual application, and Project Realization is the most difficult.

Summary of the invention

It is an object of the invention to provide a kind of reasonable in design and have good stable state and dynamic characteristic based on self adaptation The micro-capacitance sensor stable control method that sliding formwork controls.

The technical solution realizing the object of the invention is: a kind of micro-capacitance sensor stability contorting based on adaptive sliding-mode observer Method, comprises the following steps:

Step A, for micro-grid connection run with islet operation time operation characteristic, set up the number of inverter system respectively Learn model；

Step B, control to combine by Self Adaptive Control and sliding formwork, build respectively and be incorporated into the power networks and inverter during islet operation The adaptive sliding-mode observer model of system；

Step C, the adaptive sliding-mode observer rule of inverter system act on pulse width modulation (PWM), to three-phase inversion Device is controlled, thus realizes the three-phase inverter adaptive sliding-mode observer that micro-capacitance sensor is stable.

Compared with prior art, the remarkable advantage of the present invention is: 1) the adaptive sliding-mode observer method that the present invention proposes can To ensure system robustness under uncertainty and nonlinear condition, in the case of external interference and stability.2) present invention carries The control method gone out makes microgrid stabilization controller can effectively suppress micro-capacitance sensor to exchange with main electrical network when being incorporated into the power networks Power swing, it is ensured that micro-capacitance sensor is controlled with main electrical network exchange power.3) control method of the present invention makes micro-capacitance sensor stability contorting Device can provide voltage, frequency support for the micro-capacitance sensor in the case of islet operation.4) control method that the present invention proposes can be real Existing micro-capacitance sensor is seamless switching between grid-connected and 2 kinds of operational modes of isolated island.

Accompanying drawing explanation

Fig. 1 is the structural representation of existing micro-capacitance sensor.

Fig. 2 is the control system block diagram based on adaptive sliding mode of the present invention.

Fig. 3 is microgrid stabilization controller AC voltage oscillogram, and wherein figure (a) is 0.45 0.55s voltage waveform, Figure (b) is 0.95 1.05s voltage waveform, and figure (c) is 1.45 1.55s voltage waveforms, and figure (d) is 1.7 1.8s voltage waves Shape.

Fig. 4 is microgrid stabilization controller ac-side current oscillogram, and wherein figure (a) is 0.45 0.55s current waveform, Figure (b) is 0.95 1.05s current waveform, and figure (c) is 1.45 1.55s current waveforms, and figure (d) is 1.7 1.8s current waves Shape.

Fig. 5 is microgrid stabilization controller output figure.

Fig. 6 is distributed power source output voltage waveform, and wherein figure (a) is 0.45 0.55s voltage waveform, and figure (b) is 0.95 1.05s voltage waveform, figure (c) is 1.45 1.55s voltage waveforms, and figure (d) is 1.7 1.8s voltage waveforms.

Fig. 7 is distributed power source output current wave figure, and wherein figure (a) is 0.45 0.55s current waveform, and figure (b) is 0.95 1.05s current waveform, figure (c) is 1.45 1.55s current waveforms, and figure (d) is 1.7 1.8s current waveforms.

Fig. 8 is distributed power source output figure.

Fig. 9 is the exchange power diagram of major network and micro-capacitance sensor.

Detailed description of the invention

The present invention analyzes the operation characteristic of stability controller according to the different running method of micro-capacitance sensor, set up respectively grid-connected with The mathematical model of stability controller during islet operation.In view of the uncertainty of system and non-linear, with the tracking of control variable Self Adaptive Control, as the input of controller, is controlled to combine by error with sliding formwork, the adaptive sliding mode of design inverter system Control law acts on pulse width modulation, is controlled three-phase inverter, it is ensured that system Parameter uncertainties, exist extraneous dry Stable state when disturbing and dynamic characteristic.

A kind of based on adaptive sliding-mode observer the micro-capacitance sensor stable control method of the present invention, comprises the following steps:

Step A, being incorporated into the power networks and operation characteristic during islet operation for micro-capacitance sensor, set up inverter system respectively Mathematical model；

When described micro-grid connection is run, the mathematical model of inverter system is:

${\stackrel{\·}{e}}_i=a(e_i+i_{ref})+{\mathrm{bu}}_{con1}+{\mathrm{cu}}_0-{\stackrel{\·}{i}}_{ref}+w$

In formula, e_i=diag (i_0a-i_refa,i_0b-i_refb,i_0c-i_refc), i_0a、i_0b、i_0cWith i_refa、i_refb、i_refcTable respectively Show microgrid stabilization controller AC phase current actual value, reference value；A=diag (-R_a/L_ga,-R_b/L_gb,-R_c/L_gc), L_ga、 L_gb、L_gcFor filter inductance value, R_a、R_b、R_cFor converter bridge, inductance and line equivalent series impedance；i_ref=diag (i_refa, i_refb,i_refc)；B=diag (1/L_ga,1/L_gb,1/L_gc), u_con1=diag (u_con1a,u_con1b,u_con1c), u_con1a、u_con1b、 u_con1cControl signal when running for micro-grid connection；C=diag (-1/L_ga,-1/L_gb,-1/L_gc), u₀=diag (u_0a,u_0b, u_0c), u_0a、u_0b、u_0cRepresent microgrid stabilization controller AC three-phase voltage；W is the total uncertain of system；

During described micro-capacitance sensor islet operation, the mathematical model of inverter system is:

${\stackrel{\·}{X}}_k=A_k{X}_k+D_k{I}_{ok}+B_k(U_k+W_k)$

In formula,C_a、C_b、C_cFor filtering Electric capacity,B_k=[0 1/L_gkC_k]^T, U_k=[u_con2k], u_con2kFor control signal during micro-capacitance sensor islet operation, W_kTotal indeterminate for system.

The total indeterminate of system when described micro-grid connection is run is:

W=Δ a (e_i+i_ref)+Δbu_con1+Δcu₀+u_m

In formula, Δ a, Δ b, Δ c characterize the uncertainty of system, u_m=diag (u_ma,u_mb,u_mc), u_ma、u_mb、u_mcCharacterize The disturbance quantity that transient changing in micro-capacitance sensor, system parameter variations cause；

The total indeterminate of system during described micro-capacitance sensor islet operation is:

W_k=G_kX_k+H_kU_k+J_kI_0k+K_k

In formula: G_k=Δ A_k/B_k, H_k=Δ B_k/B_k, J_k=Δ D_k/B_k, K_k=F_kI_mk/B_kFor satisfied of indeterminate Join the coefficient of condition, wherein Δ A_k、ΔB_k、ΔD_kThe uncertainty of sign system,

Step B, control to combine by Self Adaptive Control and sliding formwork, build respectively and be incorporated into the power networks and inverter during islet operation The adaptive sliding-mode observer model of system；

When described micro-grid connection is run, the self adaptation total-sliding-mode control rule of three-phase inverter is:

$u_{con1}=-{\mathrm{\βe}}_i-b^{-1}({\mathrm{ai}}_{ref}+{\mathrm{cu}}_0+{\stackrel{\·}{i}}_{ref}+\mathrm{\ϵ}sign(s\left)\right)-bs\·abs{\left(bs\right)}^{-1}\hat{q}$

In formula, β is feedback of status coefficient, and ε is little normal number, global sliding mode face matrix when s is to be incorporated into the power networks, s= diag(s_a,s_b,s_c), sign () represents sign function, sign (s)=diag (sign (s_a),sign(s_b),sign(s_c))； Abs () represents the function that takes absolute value；It is the estimated value of q, probabilistic upper bound of q system；

During described micro-capacitance sensor islet operation, the self adaptation total-sliding-mode control rule of three-phase inverter is:

$\begin{array}{c}{u}_{con2k}=-{\mathrm{\βe}}_k-{\left(C_k{B}_k\right)}^{-1}(C_k{A}_k{C}_{rk}-C_k{\stackrel{\·}{X}}_{rk}+C_k{D}_k{I}_{0k}+\mathrm{\ϵ}sign(S_k\left)\right)\\ -\left(B_k^T{C}_k^T{S}_k\right)\left|\right|S_k^T{C}_k{B}_k|{|}^{-1}({\hat{q}}_{1k}+{\hat{q}}_{2k}|\left|e_k\right|\left|\right)\end{array}$

In formula, β is feedback of status coefficient matrix, e_kFor microgrid stabilization controller AC output voltage error,u_refkRepresent microgrid stabilization controller AC output voltage reference value；C_kFor full rank constant Matrix,ε is little normal number, and sign () represents sign function, S_kFor overall situation during islet operation Sliding-mode surface,It is q respectively_1k、q_2kEstimated value, q_1k、q_2kThe upper bound coefficient of system.

When described micro-grid connection is run, global sliding mode face is:

During described micro-capacitance sensor islet operation, global sliding mode face is:

Step C, the adaptive sliding-mode observer model of inverter system is acted on pulse width modulation (PWM), to three contraries Become device to be controlled, thus realize the three-phase inverter adaptive sliding-mode observer that micro-capacitance sensor is stable.

A kind of realize above-mentioned micro-capacitance sensor stabilizing control system based on adaptive sliding-mode observer, including information acquisition module, Adaptive sliding-mode observer module, pulse width modulation module and three-phase inverter, wherein:

Information acquisition module gathers microgrid stabilization controller AC phase voltage, electric current, micro-capacitance sensor is run mould simultaneously Formula differentiates；

Adaptive sliding-mode observer module carries out the STATE FEEDBACK CONTROL under corresponding operational mode, robust control to the signal received System, Self Adaptive Control process, and result are transferred to pulse width modulation module；

Pulse width modulation module is sent to six switches of three-phase inverter after the signal received is carried out pulsewidth modulation, it is achieved To three-phase inverter adaptive sliding-mode observer.

The present invention develops microgrid stabilization controller based on energy storage device, it is ensured that micro-capacitance sensor is at grid-connected, 2 kinds of moulds of isolated island Stable operation under formula and the flexible switching between 2 kinds of operational modes.The control algolithm that DG is incorporated into the power networks is sent out through long-term Exhibition and improvement, the relative maturity of the application in Practical Project.After installing microgrid stabilization controller additional in micro-capacitance sensor, DG without Change original for the control system being incorporated into the power networks, in the case of micro-capacitance sensor isolated island, may continue to stable operation.

Present invention micro-capacitance sensor based on self adaptation total-sliding-mode control stable control method, it is possible to ensure that micro-capacitance sensor is in difference Stability under operational mode: effectively suppress when micro-grid connection is run micro-capacitance sensor to exchange power swing with main electrical network, reach Controlled with main electrical network exchange power to micro-capacitance sensor；When micro-capacitance sensor islet operation, it is provided that voltage, frequency support；Realize micro-capacitance sensor Seamless switching between 2 kinds of operational modes.

It is described in more detail below.

A kind of based on adaptive sliding-mode observer the micro-capacitance sensor stable control method of the present invention, is micro-as shown in Figure 1 Electric network composition and realization in control system based on adaptive sliding mode as shown in Figure 2.Micro-capacitance sensor circuit structure such as Fig. 1 institute Showing, microgrid stabilization controller and photovoltaic, miniature gas turbine distributed power supply and important load are by 1 common bus Micro-capacitance sensor is formed after parallel connection.Micro-capacitance sensor is accessed main electrical network by points of common connection circuit breaker Q F.Microgrid stabilization controller is mainly wrapped Include energy storage device, inverter based on full-controlled device, wave filter and control testing circuit.

Circuit breaker Q F closes, and micro-grid connection is run, and in micro-capacitance sensor, voltage, frequency keep consistent with main electrical network.For fully Utilizing DG equipment, the DG in micro-capacitance sensor runs on its maximum power point.But using wind energy, solar energy etc. as primary energy point Cloth power supply is affected by the extraneous factor such as natural environment, weather, and output all exists certain fluctuation.Therefore, it can profit Compensate DG by microgrid stabilization controller and go out fluctuation, it is to avoid the problems such as the voltage deviation that caused by power swing, voltage pulsation. Commonly connected point breaker disconnects, micro-capacitance sensor islet operation, stability controller provide voltage and frequency to support, balance micro-capacitance sensor Interior power.Ensure DG stable operation and the power supply of important load.If the gross capability of DG is more than the damage in load and micro-capacitance sensor Consumption, is stored part electric energy by stability controller；Otherwise, exportable power, compensate power difference.

For the ease of analyzing, it is assumed that the voltage of energy-storage system keeps constant, therefore energy storage system can be replaced with DC source System.u_0a、u_0b、u_0cWith i_0a、i_0b、i_0cRepresent AC phase voltage and electric current respectively.L_ga、L_gb、L_gcWith C_a、C_b、C_cFor filtered electrical Sense, electric capacity.R_a、R_b、R_cFor converter bridge, inductance and line equivalent series resistance.i_ma、i_mb、i_mcCharacterize the transient state in micro-capacitance sensor to become The disturbance quantity that change, system parameter variations cause.

The present invention is a kind of micro-capacitance sensor stable control method based on adaptive sliding-mode observer.First, according to grid-connected and lonely The operating characteristic of inverter system under the method for operation of island, sets up corresponding mathematical model respectively, sets up grid-connected and isolated island fortune respectively The mathematical model of stability controller during row.In view of the uncertainty of system and non-linear, make with the tracking error of control variable For the input of controller, control to combine with sliding formwork by Self Adaptive Control, the adaptive sliding-mode observer rule of design inverter system Act on pulse width modulation, three-phase inverter be controlled, it is ensured that system at Parameter uncertainties, there are the feelings such as external interference Stable state under condition and dynamic characteristic.

The control method of the present invention comprises the following steps:

Step 1: the foundation of mathematical model

Step 1-1: mathematical model when micro-grid connection is run

Micro-grid connection is run, the power swing that microgrid stabilization controller suppression DG, load cause.At this point it is possible to it is logical Cross control microgrid stabilization controller AC output electric current to control its output, the state equation of system is represented by

In formula: L_g=diag (L_ga,L_gb,L_gc), i₀=diag (i_0a,i_0b,i_0c), R=diag (R_a,R_b,R_c),u₀=diag (u_0a,u_0b,u_0c), u_m=diag (u_ma,u_mb,u_mc), u_con1=diag (u_con1a, u_con1b,u_con1c), u_0a、u_0b、u_0cWith i_0a、i_0b、i_0cRepresent microgrid stabilization controller AC phase voltage, electric current respectively；u_ma、 u_mb、u_mcThe disturbance quantity that transient changing in sign micro-capacitance sensor, system parameter variations cause.

If microgrid stabilization controller AC output current reference value is i_ref=diag (i_refa,i_refb,i_refc), take ginseng The difference examining signal and state variable becomes as new state variable, the state equation of system

$L_g{\stackrel{\·}{e}}_i=-R_g{e}_i+u_{con2}-R_g{i}_{ref}-u_0-u_m-L_g{\stackrel{\·}{i}}_{ref}---\left(2\right)$

In formula: e_i=diag (i_0a-i_refa,i_0b-i_refb,i_0c-i_refc)

Rewritable it is:

In formula: a=diag (-R_a/L_ga,-R_b/L_gb,-R_c/L_gc), b=diag (1/L_ga,1/L_gb,1/L_gc), c=diag (- 1/L_ga,-1/L_gb,-1/L_gc)。

In view of variation and the uncertain disturbances of systematic parameter, formula (3) can be further rewritten as:

${\stackrel{\·}{e}}_i=(a+\mathrm{\Δ}a)(e_i+i_{ref})+(b+\mathrm{\Δ}b)u_{con2}+(c+\mathrm{\Δ}c)(u_0^T+u_m^T)-{\stackrel{\·}{i}}_{ref}$

$\left(4\right)$

${\stackrel{\·}{e}}_i=a({\stackrel{\·}{e}}_i+i_{ref})+{\mathrm{bu}}_{con2}+{\mathrm{cu}}_0-{\stackrel{\·}{i}}_{ref}+w---\left(5\right)$

Δ a, the uncertainty of Δ b, Δ c sign system in formula.

The uncertainty assuming system is w, and has:

W=Δ a (e_i+i_ref)+Δbu_con1+Δcu₀+u_m

(6)

Assume to there is unknown normal number diagonal matrix q=diag (q_a,q_b,q_c) so that the uncertainty of system meets:

|w|≤q

(7)

Step 1-2: mathematical model during micro-capacitance sensor islet operation

During micro-capacitance sensor islet operation, the control target of microgrid stabilization controller be output voltage be that amplitude, frequency are certain Sine wave.Therefore the state equation of system is represented by

${\stackrel{\·}{X}}_k=A_k{X}_k+B_k{U}_k+D_k{I}_{ok}+F_k{I}_{mk}---\left(8\right)$

In formula:

B_k=[0 1/L_gkC_k]^T, U_k=[u_con2k],

u_con2kFor three-phase modulations ripple.

The disturbance quantity caused in view of the transient changing in micro-capacitance sensor, system parameter variations, formula (8) can be further rewritten as

${\stackrel{\·}{X}}_k=(A_k+{\mathrm{\ΔA}}_k)X_k+(B_k+{\mathrm{\ΔB}}_k)U_k+(D_k+{\mathrm{\ΔD}}_k)I_{ok}+F_k{I}_{mk}---\left(9\right)$

In formula: Δ A_k、ΔB_k、ΔD_kUncertainty and the indeterminate of sign system meet matching condition, i.e. Δ A_k= B_kG_k, Δ B_k=B_kH_k, Δ D_k=B_kJ_k, F_kI_mk=B_kK_k.For ease of analyzing, definition:

W_k=G_kX_k+H_kU_k+J_kI_0k+K_k

(10)

Formula (9) is reduced to

${\stackrel{\·}{X}}_k=A_k{X}_k+D_k{I}_{ok}+B_k(U_k+W_k)---\left(11\right)$

Assume to there is unknown normal number so that the uncertainty of system meets:

||W_k||≤q_1k+q_2k||e_k||

(12)

E in formula_kFor microgrid stabilization controller AC output voltage error, and have:

$e_k=\left[\begin{array}{c}{u}_{0k}-u_{refk}\\ {\stackrel{\·}{u}}_{0k}-{\stackrel{\·}{u}}_{refk}\end{array}\right]=\left[\begin{array}{c}{e}_{uk}\\ {\stackrel{\·}{e}}_{uk}\end{array}\right]---\left(13\right)$

U in formula_refkRepresent microgrid stabilization controller AC output voltage reference value, be generally set to specified Value.

Step 2 is based on adaptive sliding-mode observer system

Self adaptation total-sliding-mode control combines the advantage that Self Adaptive Control controls with sliding formwork.Global sliding mode face is sliding in guarantee On the basis of mould control stability, eliminate the arrival motion stage that sliding formwork controls, make system all have in the overall process of response Robustness, overcomes in tradition variable-structure control and arrives the shortcoming that mode does not have robustness.

Control law is made up of feedback of status item, robust item and self adaptation item 3 part.Feedback of status item can make full use of Feedback of status and the advantage of POLE PLACEMENT USING, simplify the design of sliding-mode surface, it is ensured that the robustness of system.Robust item passes through sliding formwork Control strategy determines the basic structure of uncertain nonlinear system；According to uncertain nonlinear system and name nonlinear system Difference, utilizes sliding formwork and other parametric configurations to meet the adaptive law of overall situation Lyapunov stability, constitutes self adaptation item, can Efficiently solve during tradition sliding formwork controls it needs to be determined that parameter perturbation and the problem in the external disturbance upper bound.

The structured flowchart of self adaptation total-sliding-mode control system is as shown in Figure 2.Control system mainly includes electric current loop and electricity Pressure ring 2 part.When micro-grid connection is run, control signal u_con1a、u_con1b、u_con1cBy controlling microgrid stabilization controller Ac-side current, regulates its output.The now AC voltage u of microgrid stabilization controller_0a、u_0b、u_0cEqual to electrical network electricity Pressure, i.e. reference signal in Voltage loop are 0 with the difference of state variable, and therefore the output of microgrid stabilization controller is mainly by electric current Ring determines.When micro-capacitance sensor islet operation, by control signal u_con2a、u_con2b、u_con2cControl microgrid stabilization controller AC Voltage.In this case, the output of micro-capacitance sensor regulator is determined by the power shortage in micro-capacitance sensor, and therefore switch is disconnected Open.

Step 2-1 electric current based on adaptive sliding mode controls

The target of electric current loop is to control the ac-side current i of microgrid stabilization controller_0a、i_0b、i_0cFollow the tracks of its reference value i_refa、i_refb、i_refc.Therefore, selection global sliding mode face is

$s=e_i-{\∫}_0^t(a-\mathrm{\β}b)e_{i}ds---\left(14\right)$

S=diag (s in formula_a,s_b,s_c), β is feedback of status coefficient.

Arriving within the limited time for guarantee system and be maintained on sliding-mode surface, selection control is:

u_con1=u₁+u₂+u₃

(15)

u₁=-β e_i

(16)

$u_2=-b^{-1}({\mathrm{ai}}_{ref}+{\mathrm{cu}}_0+{\stackrel{\·}{i}}_{ref}+\mathrm{\ϵ}sign(s\left)\right)---\left(17\right)$

$u_3=-bs\·abs\left({\mathrm{bs}}^{-1}\right)\hat{q}---\left(18\right)$

In formula:

u₁For feedback of status item；u₂For robust item；u₃For self adaptation item；ε is little normal number；Sign () represents symbol Function, sign (s)=diag (sign (s_a),sign(s_b),sign(s_c))；Abs () represents the function that takes absolute value；It is q Estimated value；Parameter error isAnd adaptive law is

$\stackrel{\·}{\hat{q}}=abs\left(bs\right)---\left(19\right)$

Prove: take Lyapunov function:

$V=\frac{s^2+{\tilde{q}}^2}{2}---\left(20\right)$

Derivation can obtain:

$\stackrel{\·}{V}=s\stackrel{\·}{s}+\tilde{q}\stackrel{\·}{\tilde{q}}---\left(21\right)$

About formula (5) derivation, wushu (15), (19), formula (14) is substituted into formula (21), and abbreviation can obtain:

$\stackrel{\·}{V}=s({\mathrm{bu}}_3+w-\mathrm{\ϵ}sign(s\left)\right)+\tilde{q}\stackrel{\·}{\tilde{q}}\≤\mathrm{\ϵ}abs\left(s\right)---\left(22\right)$

Obviously, when abs (s) ≠ 0,

This show uncertain sliding mode system asymptotically stability in sliding-mode surface, as shown in formula (14).

When system arrives and is maintained at sliding-mode surface, have

$\stackrel{\·}{s}={\mathrm{ai}}_{ref}+{\mathrm{bu}}_{con2}+{\mathrm{cu}}_0-{\stackrel{\·}{i}}_{ref}+w+{\mathrm{\βbe}}_i=0---\left(23\right)$

Accordingly, there exist name equivalent control is

$u_{eq}=-b^{-1}({\mathrm{ai}}_{ref}+{\mathrm{cu}}_0-{\stackrel{\·}{i}}_{ref}+w+{\mathrm{\βbe}}_i)---\left(24\right)$

Equivalent control formula (24) is substituted into formula (5) and can obtain sliding mode:

${\stackrel{\·}{e}}_i=(a-\mathrm{\β}b)e_i---\left(25\right)$

By selecting suitable feedback of status factor beta, it is ensured that the robustness of the sliding die stance (25) of system, simultaneously The current controling characteristic of microgrid stabilization controller can also be adjusted.

Step 2-2 Control of Voltage based on adaptive sliding-mode observer

The Main Function of Voltage loop is that the AC output voltage controlling microgrid stabilization controller follows the tracks of its reference value u_refa、u_refb、u_refc, thus ensure the micro-capacitance sensor stability when islet operation.In order to reduce control error, obtain the overall situation surely Qualitative, selection global sliding mode face is

$S_k=C_k{e}_k-C_k{\∫}_0^t(A_k-B_k\mathrm{\β})e_{k}ds---\left(26\right)$

In formula:

C_kFor full rank constant matrices, and C_kB_kNonsingular, β is feedback of status coefficient matrix.

In order to make system arrive within the limited time and be maintained on sliding-mode surface, select to control:

u_con2k=u_1k+u_2k+u_3k

(27)

u_1k=-β e_k

(28)

$u_{2k}=-{\left(C_k{B}_k\right)}^{-1}(C_k{A}_k{X}_{rk}-C_k{\stackrel{\·}{X}}_{rk}+C_k{D}_k{I}_{0k}+\mathrm{\ϵ}sign(S_k\left)\right)---\left(29\right)$

$u_{3k}=-\left(B_k^T{C}_k^T{S}_k\right)\left|\right|S_k^T{C}_k{B}_k|{|}^{-1}({\hat{q}}_{1k}+{\hat{q}}_{2k}|\left|e_k\right|\left|\right)---\left(30\right)$

In formula:u_1kFor feedback of status item；u_2kFor robust item；u_3kFor self adaptation item；ε is little Normal number；Sign () represents sign function；It is q respectively_1k、q_2kEstimated value, parameter error isSelection adaptive law is

$\left\{\begin{array}{c}{\stackrel{\·}{\hat{q}}}_{1k}=\left|\right|S_k^T{C}_k{B}_k\left|\right|\\ {\stackrel{\·}{\hat{q}}}_{2k}=\left|\right|S_k^T{C}_k{B}_k\left|\right|\·\left|\right|e_k\left|\right|\end{array}\right.$

Proof takes Lyapunov function:

$V_k=\frac{S_k^T{S}_k+{\tilde{q}}_{1k}^2+{\tilde{q}}_{2k}^2}{2}---\left(31\right)$

Derivation can obtain:

$\begin{array}{c}{\stackrel{\·}{V}}_k=S_k^T{\stackrel{\·}{S}}_k+{\tilde{q}}_{1k}{\stackrel{\·}{\tilde{q}}}_{1k}+{\tilde{q}}_{2k}{\stackrel{\·}{\tilde{q}}}_{2k}=S_k^T(C_k{B}_k{W}_k-\mathrm{\ϵ}sign(S_k)+C_k{B}_k{u}_{3k})+{\tilde{q}}_{1k}{\stackrel{\·}{\tilde{q}}}_{1k}+{\tilde{q}}_{2k}{\stackrel{\·}{\tilde{q}}}_{2k}\\ =S_k^T(C_k{B}_k{W}_k-\mathrm{\ϵ}sign(S_k\left)\right)-\left|\right|S_k^T{C}_k{B}_k\left|\right|(q_{1k}+q_{2k}|\left|e_k\right|\left|\right)\end{array}---\left(32\right)$

Wushu (26) substitutes into (31) abbreviation and obtains:

${\stackrel{\·}{V}}_k\≤-\mathrm{\ϵ}\left|\right|S_k\left|\right|$

Obviously work as | | S_k| | when ≠ 0,Show uncertain sliding mode system asymptotically stability in sliding-mode surface, such as formula (26).

When system arrives and is maintained at sliding-mode surface,

${\stackrel{\·}{S}}_k=C_k{A}_k{X}_{rk}-C_k{\stackrel{\·}{X}}_{rk}+C_k{D}_k{I}_{0k}+C_k{B}_k{U}_{rk}+C_k{B}_k{W}_k+C_k{B}_k{\mathrm{\βe}}_k---\left(33\right)$

The equivalent control that can be obtained system by formula (33) is

$U_{eqk}=-{\left(C_k{B}_k\right)}^{-1}(C_k{A}_k{X}_{rk}-C_k{\stackrel{\·}{X}}_{rk}+C_k{D}_k{I}_{0k}+C_k{B}_k{W}_k+C_k{B}_k{\mathrm{\βe}}_k)---\left(34\right)$

Formula (34) is substituted into formula (11) can obtain

${\stackrel{\·}{e}}_k=A_k{e}_k-B_k{\mathrm{\βe}}_k---\left(35\right)$

By selecting suitable feedback of status coefficient matrix β, it is ensured that the robustness of the sliding die stance (35) of system, The voltage control characteristic of microgrid stabilization controller can also be adjusted simultaneously.

The adaptive sliding-mode observer method that the present invention proposes can ensure that system under uncertain and nonlinear condition, outer Robustness under boundary's disturbed condition and stability.

Embodiment

Utilizing PSCAD simulation software to set up the phantom of micro-capacitance sensor in Fig. 1, systematic parameter is shown in Table 1.Micro-capacitance sensor is stably controlled Device AC voltage reference value processed is set to 220V, 50Hz.Current reference value then takes according to the setpoint power output of stability controller Value.According to the sliding-mode surface of control system, for ensureing sliding die stance (25) and the robustness of (35) and micro-capacitance sensor stability contorting The stable state of device and dynamic characteristic, feedback of status coefficient value is respectively β=30, β=[0.002,35], ε=0.001.Distributed Power-supply system accesses micro-capacitance sensor by inverter and carries power to electrical network.

Table 1 systematic parameter

Micro-grid connection is run, and the exchange power between micro-capacitance sensor and major network is set to 20kW (micro-capacitance sensor carries) to major network； The output of distributed power source is 20kW；In micro-capacitance sensor, the power of important load consumption is 20kW.Therefore micro-capacitance sensor is stably controlled The output of device processed is set as 20kW.In the 0.5s moment, the output of distributed power source increases to 30kW；1s moment main electrical network Power-off, micro-capacitance sensor disconnects with major network, transfers islet operation to, and distributed power source output is reduced to 20kW；The 1.5s moment, distribution Formula output power of power supply is reduced to 10kW；In the 1.75s moment, the load increasing 20kW in micro-capacitance sensor is grid-connected.

Simulation result is as shown in figs. 3-9.Before 0.5s, microgrid stabilization controller output is 20kW；During 0.5s, by Output in distributed power source increases, and the output of microgrid stabilization controller is reduced to 10kW；1s moment micro-capacitance sensor After islet operation, the power-balance in micro-capacitance sensor, microgrid stabilization controller output 0kW active power.When 1.5s, owing to dividing The output of cloth power supply reduces, microgrid stabilization controller output 10kW active power；The 1.75s moment, due to micro-capacitance sensor Internal loading increases, and the output of microgrid stabilization controller increases to 30kW.When micro-grid connection is run and between main electrical network Exchange power remain at 20kW.

In whole simulation process, the voltage of microgrid stabilization controller remains constant.Although micro-capacitance sensor isolated island is transported After row, current harmonic content increases, but meets relevant power quality standard.The output voltage of distributed power source remains permanent Fixed, simulation result shows, distributed power source can ensure that stable operation.

The self adaptation total-sliding-mode control that the present invention proposes can ensure that system under uncertain and nonlinear condition, outer Robustness under boundary's disturbed condition and stability.Emulation and the results show: self adaptation total-sliding-mode control system effective Property and correctness and microgrid stabilization controller feasibility in actual applications.Microgrid stabilization controller ensure that micro- Electrical network is controlled with main electrical network exchange power；Voltage, frequency support is provided for the micro-capacitance sensor in the case of islet operation；Additionally, also may be used To realize micro-capacitance sensor seamless switching between 2 kinds of operational modes.

The above embodiment of the present invention is only for clearly demonstrating example of the present invention, and not to the present invention The restriction of embodiment.For those of ordinary skill in the field, can also be made it on the basis of the above description The change of its multi-form or variation.Here without also cannot all of embodiment be given exhaustive.And these belong to this Obvious change or variation that bright connotation is extended out still fall within protection scope of the present invention.

Claims (6)

1. a micro-capacitance sensor stable control method based on adaptive sliding-mode observer, it is characterised in that comprise the following steps:

Step A, being incorporated into the power networks and operation characteristic during islet operation for micro-capacitance sensor, set up the mathematics of inverter system respectively Model；

Step B, control to combine by Self Adaptive Control and sliding formwork, build respectively and be incorporated into the power networks and inverter system during islet operation Adaptive sliding-mode observer model；

Step C, the adaptive sliding-mode observer model of inverter system is acted on pulse width modulation (PWM), to three-phase inverter It is controlled, thus realizes the three-phase inverter adaptive sliding-mode observer that micro-capacitance sensor is stable.

Micro-capacitance sensor stable control method based on adaptive sliding-mode observer the most according to claim 1, it is characterised in that step When micro-grid connection described in A is run, the mathematical model of inverter system is:

${\stackrel{\·}{e}}_i=a(e_i+i_{ref})+{\mathrm{bu}}_{con1}+{\mathrm{cu}}_0-{\stackrel{\·}{i}}_{ref}+w$

In formula, e_i=diag (i_0a-i_refa,i_0b-i_refb,i_0c-i_refc), i_0a、i_0b、i_0cWith i_refa、i_refb、i_refcRepresent micro-respectively Network stability control device AC phase current actual value, reference value；A=diag (-R_a/L_ga,-R_b/L_gb,-R_c/L_gc), L_ga、L_gb、 L_gcFor filter inductance value, R_a、R_b、R_cFor converter bridge, inductance and line equivalent series impedance；i_ref=diag (i_refa,i_refb, i_refc)；B=diag (1/L_ga,1/L_gb,1/L_gc), u_con1=diag (u_con1a,u_con1b,u_con1c), u_con1a、u_con1b、u_con1cFor micro- Control signal when electrical network is incorporated into the power networks；C=diag (-1/L_ga,-1/L_gb,-1/L_gc), u₀=diag (u_0a,u_0b,u_0c), u_0a、u_0b、 u_0cRepresent microgrid stabilization controller AC three-phase voltage；W is the total uncertain of system；

During described micro-capacitance sensor islet operation, the mathematical model of inverter system is:

${\stackrel{\·}{X}}_k=A_k{X}_k+D_k{I}_{ok}+B_k(U_k+W_k)$

In formula,K=a, b, c,C_a、C_b、C_cFor filter capacitor, B_k=[0 1/L_gkC_k]^T, U_k=[u_con2k], u_con2kFor micro-capacitance sensor Control signal during islet operation, W_kTotal indeterminate for system.

Micro-capacitance sensor stable control method based on adaptive sliding-mode observer the most according to claim 1, it is characterised in that step When micro-grid connection described in B is run, the self adaptation total-sliding-mode control rule of three-phase inverter is:

$u_{con1}=-{\mathrm{\βe}}_i-b^{-1}({\mathrm{ai}}_{ref}+{\mathrm{cu}}_0+{\stackrel{\·}{i}}_{ref}+\mathrm{\ϵ}sign(s\left)\right)-bs\·abs{\left(bs\right)}^{-1}\hat{q}$

In formula, β is feedback of status coefficient, and ε is little normal number, global sliding mode face matrix when s is to be incorporated into the power networks, s=diag (s_a,s_b,s_c), sign () represents sign function, sign (s)=diag (sign (s_a),sign(s_b),sign(s_c))；abs () represents the function that takes absolute value；It is the estimated value of q, probabilistic upper bound of q system；

During described micro-capacitance sensor islet operation, the self adaptation total-sliding-mode control rule of three-phase inverter is:

$\begin{array}{c}{u}_{con2k}=-{\mathrm{\βe}}_k-{\left(C_k{B}_k\right)}^{-1}\left(C_k{A}_k{X}_{rk}-C_k{\stackrel{\·}{X}}_{rk}+C_k{D}_k{I}_{0k}+\mathrm{\ϵ}sign\left(S_k\right)\right)\\ -\left(B_k^T{C}_k^T{S}_k\right)\left|\right|S_k^T{C}_k{B}_k|{|}^{-1}\left({\hat{q}}_{1k}+{\hat{q}}_{2k}\left|\right|e_k\left|\right|\right)\end{array}$

In formula, β is feedback of status coefficient matrix, e_kFor microgrid stabilization controller AC output voltage error,u_refkRepresent microgrid stabilization controller AC output voltage reference value；C_kFor full rank constant Matrix,ε is little normal number, and sign () represents sign function, S_kFor overall situation during islet operation Sliding-mode surface, It is q respectively_1k、q_2kEstimated value, q_1k、q_2kThe upper bound coefficient of system.

Micro-capacitance sensor stable control method based on adaptive sliding-mode observer the most according to claim 2, it is characterised in that institute The total indeterminate of system when the micro-grid connection stated is run is:

W=Δ a (e_i+i_ref)+Δbu_con1+Δcu₀+u_m

In formula, Δ a, Δ b, Δ c characterize the uncertainty of system, u_m=diag (u_ma,u_mb,u_mc), u_ma、u_mb、u_mcCharacterize micro-capacitance sensor In transient changing, the disturbance quantity that causes of system parameter variations；

The total indeterminate of system during described micro-capacitance sensor islet operation is:

W_k=G_kX_k+H_kU_k+J_kI_0k+K_k

In formula: G_k=Δ A_k/B_k, H_k=Δ B_k/B_k, J_k=Δ D_k/B_k, K_k=F_kI_mk/B_kMatching condition is met for indeterminate Coefficient, wherein Δ A_k、ΔB_k、ΔD_kThe uncertainty of sign system,

Micro-capacitance sensor stable control method based on adaptive sliding-mode observer the most according to claim 3, it is characterised in that: described Micro-grid connection run time global sliding mode face be:

During described micro-capacitance sensor islet operation, global sliding mode face is:

6. one kind realizes micro-capacitance sensor stabilizing control system based on adaptive sliding-mode observer described in claim 1, it is characterised in that Including information acquisition module, adaptive sliding-mode observer module, pulse width modulation module and three-phase inverter, wherein:

Information acquisition module gathers microgrid stabilization controller AC phase voltage, electric current, enters micro-capacitance sensor operational mode simultaneously Row differentiates；

Adaptive sliding-mode observer module to receive signal carry out the STATE FEEDBACK CONTROL under corresponding operational mode, robust control, Self Adaptive Control processes, and result is transferred to pulse width modulation module；

Pulse width modulation module is sent to six switches of three-phase inverter after the signal received is carried out pulsewidth modulation, it is achieved to three Phase inverter adaptive sliding-mode observer.