CN105870975A - Micro-grid structure and power quality control method thereof - Google Patents

Abstract

The invention provides a micro-grid structure and a power quality control method thereof. The micro-grid structure comprises a plurality of distributive micro sources and a common busbar. The distributive micro sources are parallelly connected to the common busbar through corresponding feeder lines and respectively connected with nonlinear loads and linear loads, and the common busbar is connected with the nonlinear loads and the linear loads. A first switch is in parallel connection with an isolation transformer to control an input state of an inverter for compensation. A static switch which is an option switch is arranged at a point of common coupling, and option ends of the static switch correspond to a large power grid side and a ground terminal respectively.

Description

A kind of micro-capacitance sensor structure and electric energy quality control method thereof

Technical field

The present invention relates to electric power network technique field, particularly relate to a kind of micro-capacitance sensor structure and electric energy matter thereof Amount control method.

Background technology

At present, in conjunction with electricity consumption and the regulatory requirement of electrical network, increasing consumer networks is by big The pattern of electrical network and micro-grid connection sets up electrical network, by entering the operation of bulk power grid and micro-capacitance sensor Row controls, thus controls the quality of power supply of whole consumer networks.

Micro-capacitance sensor, as the effective carrier of distributed power source, comprises various forms of micro-source, energy storage The equipment such as device, energy conversion device, protection device and load control unit, and can be real Existing self-contr ol, the compact electrical generating systems protected and manage, can run on isolated island and grid-connected two kinds Pattern.

Micro-capacitance sensor is effective utilization of the raising of power system power supply reliability, regenerative resource, Reduction etc. with environmental pollution and electric energy loss provides new effective way.But for structure The micro-capacitance sensor day by day complicated with electric load, the situation that multiple power quality problem occurs simultaneously is more Come the most.How power quality problem is carried out the comprehensive regulation, be to ensure that security of system, reliable The key that ground runs.

For solving micro-capacitance sensor power quality problem, the relevant electric energy of configuration in micro-capacitance sensor the most mostly Quality regulator, such as: Research on Unified Power Quality Conditioner, Active Power Filter-APF is static Reactive-load compensator etc., but to solve multiple power quality problem simultaneously and need many covering devices, these Device can introduce additional investment, increase the complexity of system.

In recent years, scholar is also had to propose to use multi-functional combining inverter to its access point electric energy matter Amount problem is administered, but cannot solve under micro-grid connection operational mode, bulk power grid voltage wave Dynamic, uneven, distortion, short time voltage interrupts and in micro-capacitance sensor, public nonlinear load brings Power quality problem.Also have based on connection in series-parallel current transformer compensation scheme, improve converter structure Method improve the micro-capacitance sensor quality of power supply.

But, these methods are all only to solve micro-capacitance sensor part power quality problem, and for knot Structure complexity and the diversified grid-connected micro-capacitance sensor of load, needing to consider affects power quality problem Many factors, improve power supply reliability and the quality of power supply of micro-capacitance sensor as far as possible.

Summary of the invention

In view of the above problems, it is proposed that for overcome the problems referred to above a kind of micro-capacitance sensor structure and Electric energy quality control method.

According to one aspect of the present invention, it is provided that a kind of micro-capacitance sensor structure, including some distributions Decline source and common bus；It is characterized in that, described some distributions decline source by corresponding feeder line And receive on described common bus, the described distribution source of declining is connected to nonlinear load and line Property load, on described common bus connect have nonlinear load and linear load；First switch with Isolating transformer is connected in parallel, the input state of described first switch control rule compensation inverter； Static switch it is provided with at points of common connection；Described static switch is for selecting switch, and described static state is opened The selection end closed corresponds respectively to bulk power grid side and earth terminal.

Wherein, when described static switch is connected to bulk power grid side, micro-capacitance sensor is in the mould that is incorporated into the power networks Formula, described compensation inverter is connected on bulk power grid side by isolating transformer；Static switch connects During to earth terminal, micro-capacitance sensor is in islet operation pattern, described compensation inverter and micro-capacitance sensor In parallel；Wherein, it is incorporated into the power networks under pattern, when the bulk power grid quality of power supply is unsatisfactory for micro-capacitance sensor operation, Switch to islet operation pattern.

Wherein, under grid-connect mode, it is distributed the source that declines and uses P Q based on grid voltage orientation control System strategy；Wherein, voltage and the frequency of micro-capacitance sensor are supported by bulk power grid, and described distribution declines source Use P based on grid voltage orientation Q control strategy, described P Q control strategy include outer shroud Power ring and inner ring electric current loop.

Wherein, described compensation inverter control includes that harmonic compensation controls and points of common connection electricity Energy quality control, harmonic compensation controls to use virtual impedance method, compensates bulk power grid harmonic wave, Described compensation inverter act as harmonic wave resistance.

Wherein, under described island mode, described compensation inverter is used as parallel-connection type active power Wave filter, compensates public nonlinear load harmonic, ensures the points of common connection quality of power supply.

Wherein, the described distribution source that declines uses the droop control plan compensated based on local harmonic wave this locality Slightly, it is ensured that the output electric current in the source that while output voltage quality declines distribution is controlled, public Synteny load is divided equally by each self-capacity by each distribution source that declines, and described compensation inverter uses Mixed-voltage current control method, compensates common load harmonic current.

Wherein, compensating instruction voltage is that harmonic compensation controls lower compensating instruction voltage and commonly connected Compensating instruction voltage sum under some quality of power supply shaping modes, uses the control plan of PI+ Repetitive controller Slightly carry out voltage-tracing.

According to another aspect of the present invention, it is provided that the quality of power supply control of a kind of micro-capacitance sensor structure Method processed, including: step 1, micro-capacitance sensor is initially the pattern of being incorporated into the power networks, and compensation inverter leads to Cross isolating transformer to be connected in series with bulk power grid；Step 2, described in be incorporated into the power networks under pattern, distribution Decline source use P based on grid voltage orientation Q control strategy；Step 3, described in be incorporated into the power networks Under pattern, compensation inverter control includes that harmonic compensation controls and the points of common connection quality of power supply Controlling, compensating instruction voltage is that harmonic compensation controls lower compensating instruction voltage and points of common connection electricity Compensating instruction voltage sum under energy quality adjustment pattern, uses the control strategy of PI+ Repetitive controller to enter Row voltage-tracing；Step 4, when the bulk power grid quality of power supply is unsatisfactory for requiring, enters islet operation Pattern, compensation inverter is in parallel with micro-capacitance sensor, it is achieved parallel connection type active electric filter function.

Wherein, in step 2, bulk power grid supports the voltage of micro-capacitance sensor and frequency, each in micro-capacitance sensor The individual distribution source that declines only controls power output, to ensure that micro-capacitance sensor internal power balances；Distributed Micro-source use P based on grid voltage orientation Q control strategy, described P Q control strategy include Exterior ring power ring and inner ring electric current loop.

Wherein, in step 3, described compensation inverter control includes harmonic compensation control and public affairs Tie point utility power quality control altogether, harmonic compensation controls to use virtual impedance method, humorous to bulk power grid Ripple compensates, and described compensation inverter control becomes harmonic wave resistance.

Compared with prior art, this structure and method advantage are:

1, multiple power quality problem can be solved simultaneously, be incorporated into the power networks under pattern, can effectively mend Repay bulk power grid voltage pulsation, imbalance and harmonic distortion, stop micro-capacitance sensor harmonic injection bulk power grid.

2, when the interruption of bulk power grid short time voltage, generation instantaneity short trouble, compensation inversion Device injects active power to micro-capacitance sensor, compensates bulk power grid Voltage Drop, imbalance and harmonic wave simultaneously, Ensure that micro-capacitance sensor not off-grid runs, improve the anti-islanding ability of micro-capacitance sensor.

3, when micro-capacitance sensor islet operation, inverter is in parallel with micro-capacitance sensor by switch ground connection, fills Work as parallel active filter, it is achieved dual-use, reduce the operating cost of system..

Accompanying drawing explanation

By reading the detailed description of hereafter preferred embodiment, various other advantage and benefit Those of ordinary skill in the art be will be clear from understanding.Accompanying drawing is only used for illustrating and is preferable to carry out The purpose of mode, and it is not considered as limitation of the present invention.And in whole accompanying drawing, use Identical reference symbol represents identical parts.In the accompanying drawings:

Fig. 1 is that this locality according to the present invention and common bus are all with the micro-capacitance sensor of nonlinear load Topological structure schematic diagram；

Fig. 2 is according to being distributed the source P/Q control structure figure that declines under the grid-connect mode of the present invention；

Fig. 3 is the compensation inverter structure figure according to the present invention；

Fig. 4 is the one phase equivalent circuit figure based on virtual impedance method according to the present invention；

Fig. 5 is that under the mains by harmonics current compensation pattern according to the present invention, compensation inverter compensates Voltage instruction generates schematic diagram；

Fig. 6 is that under the PCC quality of power supply shaping modes according to the present invention, compensation inverter compensates Voltage instruction generates schematic diagram；

Fig. 7 is according to compensation inverter master control block diagram under the pattern that is incorporated into the power networks of the present invention；

Fig. 8 is the grid-connected micro-grid system control structure figure according to the embodiment of the present invention；

Fig. 9 a is not add compensation inverter simulated grid current wave according to the embodiment of the present invention Shape schematic diagram；

Fig. 9 b is not add compensation inverter emulation PC C point voltage according to the embodiment of the present invention Waveform diagram；

Figure 10 a is that the addition compensation inverter grid voltage sags according to the embodiment of the present invention is imitated True power network current waveform diagram；

Figure 10 b is that the addition compensation inverter grid voltage sags according to the embodiment of the present invention is imitated True PCC point voltage waveform diagram；

Figure 10 c is that the addition compensation inverter grid voltage sags according to the embodiment of the present invention is imitated True compensation uses inverter output voltage waveform diagram；

Figure 11 a is that the addition compensation inverter one-phase short trouble according to the embodiment of the present invention is imitated True grid voltage waveform schematic diagram；

Figure 11 b is that the addition compensation inverter one-phase short trouble according to the embodiment of the present invention is imitated True PCC point voltage waveform diagram；

Figure 11 c is that the addition compensation inverter one-phase short trouble according to the embodiment of the present invention is imitated True compensation uses inverter output voltage waveform diagram.

Detailed description of the invention

With embodiment, embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings. Following example are used for illustrating the present invention, but can not be used for limiting the scope of the present invention.

Fig. 1 is a kind of microgrid topology structure figure according to the embodiment of the present invention, wherein, and distribution Decline source and common bus all with nonlinear load.Wherein, micro-capacitance sensor includes some distributed Micro-source, common bus, compensation inverter and isolating transformer, also include nonlinear load, Linear load, the first switch K, static switch S.Wherein, described some distributions decline source (send out Electric unit) be connected in parallel, described distribution decline source connect have described nonlinear load and linear negative Carrying, described some distributions source that declines is connected on described common bus by respective feed connection, described Common bus is provided with described nonlinear load and linear load.

Wherein, compensation inverter and the first switch K are in parallel, the input of control and compensation inverter State, K opens compensation inverter and devotes oneself to work, and during Guan Bi, compensation inverter is not devoted oneself to work.Quiet State switch is for selecting switch, and switch selects end to correspond respectively to bulk power grid side and earth terminal.

Wherein, when described first switch is opened, compensation inverter is devoted oneself to work, and compensates during Guan Bi Not devoting oneself to work with inverter, when micro-grid connection is run, described inverter is by isolation transformation Device is connected on bulk power grid side；During micro-capacitance sensor islet operation, described inverter is by switching ground connection with micro- Electrical network is in parallel.

The control method of the present invention specifically includes following steps:

(1) micro-capacitance sensor initial launch is in grid-connect mode, i.e. switch S gets at 1, now inverter It is connected in series with bulk power grid by isolating transformer；

(2) under the pattern of being incorporated into the power networks, it is distributed the source that declines and uses P Q based on grid voltage orientation Control strategy, in order to compensate local load harmonic, considers load current in reference voltage obtains；

Being incorporated into the power networks under pattern, voltage and the frequency of micro-capacitance sensor are supported by bulk power grid, micro-capacitance sensor In each distribution source that declines only need to control power output to ensure the flat of micro-capacitance sensor internal power Weighing apparatus, the most heretofore described distribution decline source use P Q based on grid voltage orientation control Strategy, described P Q control strategy include that exterior ring power ring and inner ring electric current loop two control ring, its Control structure is as shown in Figure 2.

Under synchronous rotating frame, distributed micro-source inverter voltage equation is:

$\left\{\begin{array}{c}{u}_{odi}=R_i{i}_{gdi}+L_i\frac{{\mathrm{di}}_{gdi}}{dt}-{\mathrm{\ωL}}_i{i}_{gqi}+u_{pccd}\\ u_{oqi}=R_i{i}_{gqi}+L_i\frac{{\mathrm{di}}_{gqi}}{dt}+{\mathrm{\ωL}}_i{i}_{gdi}+u_{pccq}\end{array}\right.$

Wherein, u_odi、u_oqiIt is respectively i-th and is distributed source output voltage d, q axle component that declines；i_gdi、 i_gqiIt is respectively the i-th distribution source of declining and flows to d, q axle component of common bus electric current；u_pccd、u_pccq It is respectively PCC point voltage d, q axle component；R_i、L_iIt is distributed the source line resistance that declines for i-th And inductance.

Exterior ring power ring uses PI to control, and its reference current is:

$\left\{\begin{array}{c}{i}_{gdi}^{*}=(P_{refi}-P_i)(k_p+\frac{k_i}{s})\\ i_{gqi}^{*}=(Q_{refi}-Q_i)(k_p+\frac{k_i}{s})\end{array}\right.$

Wherein, P_i、Q_iThe meritorious of common bus and reactive power, P is exported for micro-source_refi、Q_refi Meritorious, reactive power reference qref, k for it_p、k_iFor ratio, the integral coefficient of exterior ring power ring, Due to the existence of local nonlinear load, in order to compensate local load harmonic, need to consider this locality Load current i_ldiAnd i_lqi.Therefore, Control of Voltage equation is:

$\left\{\begin{array}{c}{u}_{odi}^{*}=(i_{gdi}^{*}+i_{ldi}-i_{gdi})(k_p+\frac{k_i}{s})-{\mathrm{\ωL}}_i{i}_{gqi}+u_{pccd}\\ u_{oqi}^{*}=(i_{gqi}^{*}+i_{lqi}-i_{gqi})(k_p+\frac{k_i}{s})+{\mathrm{\ωL}}_i{i}_{gdi}+u_{pccq}\end{array}\right.$

K in formula_p、k_iRatio, integral coefficient for inner ring electric current loop.

(3) under micro-grid connection operational mode, compensation inverter control by harmonic compensation control and Points of common connection (PCC point) utility power quality control two parts are constituted, and compensating instruction voltage is humorous Ripple compensates compensation voltage under the lower compensated voltage instruction of control and PCC point quality of power supply shaping modes and refers to Make sum, use the control strategy of PI+ Repetitive controller to carry out voltage-tracing.

Compensation inverter structure is as it is shown on figure 3, main circuit is by three-phase voltage type PWM unsteady flow Device is constituted with LC wave filter, and DC side uses battery.U in figure_sx(x=a, b c) are bulk power grid electricity Pressure, L_sFor electrical network internal resistance, i_sx(x=a, b c) are power network current, u_cx(x=a, b c) are compensation inversion Device is injected into the voltage of electrical network, u_pccx(x=a, b c) are point of common coupling i.e. PCC point voltage.

Harmonic compensation controls to use virtual impedance method, compensates bulk power grid harmonic wave, now mends Repaying and become a harmonic wave resistance with inverter control, its one phase equivalent circuit is as shown in Figure 4.In figure Z_sFor bulk power grid inside equiva lent impedance, u_sAnd i_sIt is respectively bulk power grid voltage, electric current, u_pccFor PCC Point voltage, u_cThe voltage injected to electrical network for compensation inverter.

By u_s、i_s、u_pccRepresent by fundametal compoment and harmonic component:

$\left\{\begin{array}{c}{u}_s=u_{sh}+u_{sf}\\ i_s=i_{sh}+i_{sf}\\ u_{pcc}=u_{pcch}+u_{pccf}\end{array}\right.$

If there being u_c=ki_sh, then bulk power grid harmonic current can be expressed as:

$i_{sh}=\frac{u_{sh}-u_{pcch}}{k+Z_{sh}}$

Z_shFor the Equivalent Harmonic impedance of electrical network internal resistance, from above formula, when k is sufficiently large, greatly Harmonic component i in electrical network output electric current_shLevel off to zero, thus realize harmonic compensation, at this time It is the resistance of k that compensation inverter is equivalent to a resistance for harmonic wave, and for first-harmonic For its resistance value be zero, therefore, compensation inverter compensated voltage instruction can be expressed as:

$u_{ch}^{*}={\mathrm{ki}}_{sh}$

Its instruction generates as it is shown in figure 5, k is virtual resistance value.

Voltage Drop would generally be caused when bulk power grid breaks down, and be often accompanied by during Voltage Drop The problems such as imbalance, harmonic wave, when these power quality problems are serious, micro-capacitance sensor will be with bulk power grid Disconnect, enter islet operation pattern, and the transient process that the switching of micro-capacitance sensor pattern produces will impact The stability of system and dynamic property, by the output voltage of control and compensation inverter, it is achieved To bulk power grid Voltage Drop, imbalance and harmonic compensation, PCC voltage stabilization can be maintained, protect The card PCC quality of power supply, so that micro-capacitance sensor not off-grid when bulk power grid is short-circuited fault, Presenting certain anti-islanding ability, PCC utility power quality control is specific as follows:

Line voltage u_sxUse fundamental positive sequenceNegative phase-sequenceWith harmonic wave u_shxRepresentation, neglect The slightly pressure drop in electrical network internal resistance, if PCC point voltage is referenced asThen have:

$u_{cx}^{*}=u_{sx}-u_{pccx}^{*}=(u_{sfx}^{+}-u_{pccx}^{*})+u_{sfx}^{-}+u_{shx}$

Wherein,It is chosen for amplitude equal to PCC rated value V_m, and electric with electrical network fundamental positive sequence PressureSame-phase, corresponding construction is as shown in Figure 6.The output voltage instruction of compensation inverter contains There is fundametal compomentThe active power that now compensation inverter provides to electrical network, size For:

$P_{cx}=(u_{sfx}^{+}-u_{pccx}^{*})i_{spx}$

Wherein i_spxFor power network current real component；

Using complex controll mode, compensation contravarianter voltage reference instruction is:

$u_{tx}^{*}=u_{chx}^{*}+u_{cx}^{*}={\mathrm{ki}}_{shx}+u_{sx}-u_{pccx}^{*}$

Compensate with inverter master control block diagram as it is shown in fig. 7, use Double closed-loop of voltage and current Structure, Voltage loop, the control of electric current loop are all carried out under α β coordinate system.In order to realize well Tracking fast and accurately to reference voltage, Voltage loop uses parallel connection type PI+ Repetitive controller.Voltage The output of ring gives as the input of electric current loopCurrent loop controller is that ratio controls k_i, Its output is inverter PWM output reference voltage.

(4) when the bulk power grid quality of power supply is unsatisfactory for requiring, micro-capacitance sensor islet operation, switch S beats At 2, inverter is in parallel with micro-capacitance sensor by switch ground connection, compensates public nonlinear load humorous Ripple, it is achieved parallel connection type APF function, it is ensured that the PCC point quality of power supply, now the distribution source of declining is adopted With the droop control strategy compensated based on local harmonic wave this locality, ensureing the same of output voltage quality Time, the output electric current in the source that declines distribution is controlled, and each distribution declines source to local non-linear While load provides sinusoidal three-phase voltage and required harmonic current, provide to public linear load Required linear current, and public linear load divided equally by each self-capacity by each micro-source, described inverse Become device and use mixed-voltage current control method, compensate common load harmonic current.

Fig. 8 is embodiment grid-connected micro-grid system control structure figure, the DG of two identical capacity Parallel running, local load and nonlinear load are nonlinear load, filter inductance L_f1=L_f2=3mH, L_r=1.6mH；Filter capacitor C_f1=C_f2=40 μ F, C_r=40 μ F；Circuit Resistance, inductance R_line1=0.128 Ω, L_line1=0.064mH, R_line2=0.167 Ω, L_line2=0.083mH.

Simulation waveform when Fig. 9 is not for adding compensation inverter.During t=0s, bulk power grid output electricity The voltage crest value sinusoidal three-phase voltage equal to 311V, during t=0.1s, Voltage Drop 20%, by FFT Analysis can obtain, and in 0.05～0.1s period, bulk power grid output electric current THD is 15.64%； 0.1～0.15s period, bulk power grid output electric current THD is 13.67% bulk power grid Current harmonic distortion Rate is higher, and therefore direct grid-connected is the most feasible.

During t=0.2s, the compensated inverter of micro-capacitance sensor is connected with bulk power grid, bulk power grid output voltage Falling 20%, t=0.25s bulk power grid output voltage recovers normal.Figure 10 is for accessing compensation inversion Simulation waveform during device grid voltage sags.In 0.2～0.25s period, bulk power grid electric current THD is 4.66%, compensation inverter output voltage fundamental voltage amplitude is 59V；0.25～0.3s period, greatly electricity Net output electric current THD is 4.85%, and compensation inverter output voltage fundamental voltage amplitude is 5.1V. When bulk power grid voltage does not falls, compensation inverter only exports the harmonic compensation electricity needed for system Pressure, compensates harmonic voltage at micro-capacitance sensor PCC, thus stops harmonic current to enter bulk power grid；When When bulk power grid output voltage falls, compensation inverter not only compensation harmonic voltage stops harmonic wave electricity Stream enters bulk power grid, and the fundamental voltage compensating bulk power grid falls.

When t=0.3s, bulk power grid generation singlephase earth fault (A phase), t=0.4s Failure elimination. As shown in figure 11,0.3s～0.4s bulk power grid voltage drop, imbalance and harmonic wave are by compensating for simulation waveform Compensating with inverter, PCC point voltage still approximates three phase sine.PCC point static switch is failure to actuate, Micro-capacitance sensor is the most normally incorporated into the power networks, and can continue through B, C two-phase and swap energy with bulk power grid Amount.

Embodiments of the invention are given for the sake of example and description, and are not nothing left Leakage or limit the invention to disclosed form.Many modifications and variations are for this area It is apparent from for those of ordinary skill.Selecting and describing embodiment is to more preferably illustrate The principle of the present invention and actual application, and make those of ordinary skill in the art it will be appreciated that this Invent thus design the various embodiments with various amendments being suitable to special-purpose.

Claims (10)

1. a micro-capacitance sensor structure, declines source and common bus including some distributions；Its feature exists By corresponding feeder line and receive on described common bus in, described some distributions source that declines, described The distribution source of declining is connected to nonlinear load and linear load, and described common bus connects There are nonlinear load and linear load；First switch is connected in parallel with isolating transformer, controls to mend Repay by the input state of inverter；Static switch it is provided with at points of common connection；Described static switch For selecting switch, the selection end of described static switch corresponds respectively to bulk power grid side and earth terminal.

Micro-capacitance sensor structure the most according to claim 1, it is characterised in that described static state is opened When pass is connected to bulk power grid side, micro-capacitance sensor is in the pattern of being incorporated into the power networks, described compensation inverter It is connected on bulk power grid side by isolating transformer；When static switch is connected to earth terminal, at micro-capacitance sensor In islet operation pattern, described compensation inverter is in parallel with micro-capacitance sensor；Wherein, it is incorporated into the power networks Under pattern, when the bulk power grid quality of power supply is unsatisfactory for micro-capacitance sensor operation, switch to islet operation pattern.

Micro-capacitance sensor structure the most according to claim 2, it is characterised in that under grid-connect mode, It is distributed the source that declines and uses P Q control strategy based on grid voltage orientation；Wherein, micro-capacitance sensor Voltage and frequency are supported by bulk power grid, described distribution decline source use based on grid voltage orientation P Q control strategy, described P Q control strategy include exterior ring power ring and inner ring electric current loop.

Micro-capacitance sensor structure the most according to claim 3, it is characterised in that described compensation is used Inverter control includes that harmonic compensation controls and points of common connection utility power quality control, harmonic compensation Controlling to use virtual impedance method, compensate bulk power grid harmonic wave, described compensation inverter is made With for harmonic wave resistance.

Micro-capacitance sensor structure the most according to claim 2, it is characterised in that described isolated island mould Under formula, described compensation inverter is used as parallel connection type active electric filter, compensates public non-thread Property load harmonic, ensure the points of common connection quality of power supply.

Micro-capacitance sensor structure the most according to claim 5, it is characterised in that described distributed Micro-source uses the droop control strategy compensated based on local harmonic wave this locality, it is ensured that output voltage quality While distribution the declined output electric current in source be controlled, public linear load is by each distributed Micro-source is divided equally by each self-capacity, and described compensation inverter uses mixed-voltage current control method, Compensate common load harmonic current.

Micro-capacitance sensor structure the most according to claim 4, it is characterised in that compensating instruction electricity Press and control under lower compensating instruction voltage and points of common connection quality of power supply shaping modes for harmonic compensation Compensating instruction voltage sum, uses the control strategy of PI+ Repetitive controller to carry out voltage-tracing.

8. one kind based on the utility power quality control side of micro-capacitance sensor structure described in claims 1 or 2 Method, it is characterised in that described method includes:

Step 1, micro-capacitance sensor is initially the pattern of being incorporated into the power networks, and compensation inverter is by isolation transformation Device is connected in series with bulk power grid；

Step 2, described in be incorporated into the power networks under pattern, distribution decline source use based on grid voltage orientation P Q control strategy；

Step 3, described in be incorporated into the power networks under pattern, compensation inverter control includes harmonic compensation control System and points of common connection utility power quality control, compensating instruction voltage is that harmonic compensation controls lower compensation Compensating instruction voltage sum under command voltage and points of common connection quality of power supply shaping modes, uses The control strategy of PI+ Repetitive controller carries out voltage-tracing；

Step 4, when the bulk power grid quality of power supply is unsatisfactory for requiring, enters islet operation pattern, mends Repay with inverter in parallel with micro-capacitance sensor, it is achieved parallel connection type active electric filter function.

Method the most according to claim 8, wherein, in step 2, bulk power grid supports micro-capacitance sensor Voltage and frequency, each distribution source that declines in micro-capacitance sensor only controls power output, to ensure Micro-capacitance sensor internal power balances；Being distributed the source that declines uses P Q based on grid voltage orientation to control Strategy, described P Q control strategy include exterior ring power ring and inner ring electric current loop.

Method the most according to claim 8, wherein, in step 3, described compensation inversion Device controls to include that harmonic compensation controls and points of common connection utility power quality control, and harmonic compensation controls Using virtual impedance method, compensate bulk power grid harmonic wave, described compensation inverter control becomes Harmonic wave resistance.