CN103701118A - Micro-grid on-site operation control strategy on basis of embedded controller - Google Patents

Abstract

The invention discloses a micro-grid on-site operation control strategy on the basis of an embedded controller. The micro-grid on-site operation control strategy comprises the following steps of: acquiring phase voltages, phase currents, instantaneous currents of each power feeder and instantaneous currents of each load feeder; calculating a tie line real-time instantaneous active power, a power-supply instantaneous active power and a load instantaneous active power; feeding a power-supply injection bus active power sample and a load adsorption bus active power sample into a comparator to obtain a difference value, wherein a current control period output of a low-pass digital filter is a tie line active power reference value in a current control period; feeding the tie line active power reference value and the current tie line real-time instantaneous active power into the comparator to obtain a difference value; after adding the difference values, an energy storage system loss compensation value and an energy storage system active power reference value in a previous control period, obtaining an energy storage system active power reference value in the current control period and sending the energy storage system active power reference value in the current control period to an energy storage converter. The micro-grid on-site operation control strategy has a high response speed; electric energy can be released for the second time; the micro-grid on-site operation control strategy can be widely applied to various micro-grid systems.

Description

A kind of micro-electrical network based on embedded controller moves control strategy on the spot

Technical field

The present invention relates to a kind of micro-electrical network based on embedded controller and move on the spot control strategy, belong to intelligent microgrid field.

Background technology

At present, intelligent microgrid field is generally by adjusting the level and smooth microgrid interconnection of the mode power of adjustable heating power load.

The method exist response speed slow, absorb electric energy and be difficult to the shortcoming that secondary discharges, reduces utilization of power quality, and lack generally, cannot be applied to lack in the microgrid of adjustable heating power load.

Summary of the invention

The deficiency existing for prior art, the object of the invention is to provide a kind of micro-electrical network based on embedded controller and moves on the spot control strategy, fast response time, electric energy can discharge by secondary, can be widely used in all kinds of micro-grid systems.

To achieve these goals, the present invention realizes by the following technical solutions:

A kind of micro-electrical network based on embedded controller of the present invention moves control strategy on the spot, specifically comprises following step:

(1) by sampling module, gather phase voltage U _a, U _b, U _cand phase current I _a, I _b, I _c, and gather the three-phase transient current I of every power feeder _aGi, I _bGi, I _cGiand the three-phase transient current I of every load feeder _aLi, I _bLi, I _cLi;

(2) active-power P, power supply instantaneous active power p while calculating in real time interconnection real time instant electric discharge _gwith load instantaneous active power p _l;

(3) by the power supply instantaneous active power p of sampling _gwith load instantaneous active power p _lsend into comparator and ask difference, the current input signal using difference as lowpass digital filter, wherein, power supply instantaneous active power p _ggetting power injection generatrix direction is reference direction, load instantaneous active power p _lgetting outflow generatrix direction is reference direction;

Lowpass digital filter in S territory transfer function is:

$Y\left(S\right)=\frac{1}{1+\mathrm{TS}}\·E\left(S\right)---\left(9\right)$

Wherein, S is Laplacian, and Y is output variable, and E is input variable, and T is time constant,

After discretization, actual execution algorithm is as follows:

$Y\left(k\right)=\frac{T_c}{T_c+T}\·[E\left(k\right)-E(k-1)+Y(k-1)]---\left(10\right)$

Wherein, T _cfor control cycle, Y (k) is current control cycle output variable, E (k) is current control cycle input variable, E (k-1) is a upper control cycle input variable, Y (k-1) is a upper control cycle output variable, and the current control cycle output variable Y (k) of lowpass digital filter is the interconnection active power reference value of current control cycle;

(4) interconnection active power reference value and the real-time instantaneous active power p of current interconnection are sent into comparator and ask difference;

After providing fiducial value the energy-storage system loss balancing value obtaining through on-the-spot actual debugging and a upper control cycle energy-storage system active power reference value to be added difference, Jiang You energy accumulation current converter producer, obtain current control cycle energy-storage system active power reference value, and the order of current control cycle energy-storage system active power reference value is sent to energy accumulation current converter.

Active-power P, power supply instantaneous active power p during above-mentioned interconnection real time instant electric discharge _gwith load instantaneous active power p _lcomputational methods as follows:

By the phase voltage U gathering _a, U _b, U _cchange line voltage U into _ab, U _bc, U _caafter, then go back to actual phase voltage U _a', U _b', U _c',

Transfer phase voltage to line voltage:

$\left\{\begin{array}{c}{U}_{\mathrm{ab}}=U_a-U_b\\ U_{\mathrm{bc}}=U_b-U_c\\ U_{\mathrm{ca}}=U_c-U_a\end{array}\right.---\left(1\right)$

Transfer line voltage to actual phase voltage again:

$\left\{\begin{array}{c}{U_a}^{\′}=(U_{\mathrm{ab}}-U_{\mathrm{ca}})/3*K_u\\ {U_b}^{\′}=(U_{\mathrm{bc}}-U_{\mathrm{ab}})/3*K_u\\ {U_c}^{\′}=(U_{\mathrm{ca}}-U_{\mathrm{bc}})/3*K_u\end{array}\right.---\left(2\right)$

Wherein, K _ufor voltage, demarcate proportionality coefficient, setting method is

K _u=A _u/2 ⁿ （3）

Wherein, A _ufor voltage input range, n is sample conversion accuracy figure place;

During interconnection real time instant electric discharge, the account form of active-power P is

p=U _a'I _a'+U _b'I _b'+U _c'I _c' （4）

Wherein, I _a', I _b', I _c' be the phase current through calibration conversion, computational methods are

$\left\{\begin{array}{c}{I_a}^{\′}=I_a*K_i\\ {I_b}^{\′}=I_b*K_i\\ {I_c}^{\′}=I_c*K_i\end{array}\right.---\left(5\right)$

Wherein, K _ifor calibration with current signal proportionality coefficient, setting method is

K _i=A _i/2 ⁿ (6)

Wherein, A _ifor electric current input range;

Power supply instantaneous active power p _gaccount form be

$p_G=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aGi}}+{U_b}^{\′}{I}_{\mathrm{bGi}}+{U_c}^{\′}{I}_{\mathrm{cGi}})---\left(7\right)$

Wherein, I _aGi, I _bGi, I _cGi is respectively i bar power feeder a, b, c phase transient current;

Load instantaneous active power p _laccount form be

$p_L=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aLi}}+{U_b}^{\′}{I}_{\mathrm{bLi}}+{U_c}^{\′}{I}_{\mathrm{cLi}})---\left(8\right)$

Wherein, I _aLi, I _bLi, I _cLibe respectively i bar load feeder a, b, c phase transient current.

Above-mentioned A _uby the specified input voltage U of the super sampling module of embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value is provided by the super sampling module of embedded controller producer; A _iby the specified input current I of the super sampling module of embedded controller _indetermine with current sensor or mutual inductor ratio N, account form is A _i=I _in* N, n value is provided by the super sampling module of embedded controller producer.

It is level and smooth that the mode of the present invention by real-time digital filtering realized the active power of microgrid interconnection, overcome, electric energy slow by adjustable heating power load responding and be difficult to the shortcoming that secondary discharges, and can be widely used in all kinds of micro-grid systems; Simultaneously, adopt under this control strategy mode service conditions, energy-storage system overall average power output (electric energy) in unit long time period is 0, can meet under grid-connected condition energy-storage system in automatic smoothing microgrid interconnection power output, stable in unit long time period of carrying capacity.

Accompanying drawing explanation

Fig. 1 is embedded controller system architecture diagram of the present invention;

Fig. 2 is control strategy algorithm block diagram of the present invention.

Embodiment

For technological means, creation characteristic that the present invention is realized, reach object and effect is easy to understand, below in conjunction with embodiment, further set forth the present invention.

Embedded controller of the present invention is the important component part of micro-grid control system, must in micro-grid control system system, move.Micro-grid control system framework comprises:

(1) key-course on the spot: carry out autonomous formula controlling run by gathering the information such as local electric weight.

(2) intermediate layer: the capital equipment in intermediate layer is embedded controller, engineer can carry out field adjustable to intermediate layer program by industrial computer or individual PC.The real time information of each distributed electrical source controller of intermediate layer Real-Time Monitoring, sampling apparatus, energy-storage system, to each device issuing control policy instructions and guarded command.

(3) Long-distance Control layer: background server externally provides operator interface, shows interface and Web issuing interface.Also support telemechanical interface for scheduling or centralized control center, a distant place simultaneously.

System architecture of the present invention can be expanded the sampling of three-phase voltage, three-phase current.

Embedded controller is applied to the intermediate layer in micro-grid control system framework, and system configuration is referring to Fig. 1.

Method of the present invention is specifically applied in the microgrid with large electrical network net state.Method of the present invention comprises data acquisition and processing section and algorithm operating part.

Data acquisition and processing section specifically comprise following step:

By continuing inner each feeder current of outside voltage, interconnection electric current and microgrid in synchronous acquisition PCC point to reach as high as the frequency of 10kHz.

In this device, adopt the wiring of three-phase four-wire system Gather and input, directly gather the instantaneous value of the voltage between a, b, c three-phase and neutral point, the phase voltage directly gathering need be changed into go back to again phase voltage after line voltage can be for controlling calculating.Voltage measurement method for transformation is as follows:

Measure phase voltage and transfer slotted line voltage to:

$\left\{\begin{array}{c}{U}_{\mathrm{ab}}=U_a-U_b\\ U_{\mathrm{bc}}=U_b-U_c\\ U_{\mathrm{ca}}=U_c-U_a\end{array}\right.---\left(1\right)$

In above-mentioned formula (1), U _a, U _b, U _cfor the phase voltage value being gathered by the super sampling module of three-phase voltage current, U _ab, U _bc, U _cafor line magnitude of voltage.Transfer line voltage to calculating phase voltage again, method as shown in the formula:

$\left\{\begin{array}{c}{U_a}^{\′}=(U_{\mathrm{ab}}-U_{\mathrm{ca}})/3*K_u\\ {U_b}^{\′}=(U_{\mathrm{bc}}-U_{\mathrm{ab}})/3*K_u\\ {U_c}^{\′}=(U_{\mathrm{ca}}-U_{\mathrm{bc}})/3*K_u\end{array}\right.---\left(2\right)$

In above-mentioned formula (2), U _a', U _b', U _c' be actual phase voltage, K _ufor voltage, demarcate proportionality coefficient, setting method is

K _u=A _u/2 ⁿ （3）

In formula (3), A _ufor voltage input range, n is sample conversion accuracy figure place.

During interconnection real time instant electric discharge, active power calculating mode is

p=U _a'I _a'+U _b'I _b'+U _c'I _c' （4）

U in formula (4) _a, U _b, U _cfor phase voltage, I _a', I _b', I _c' be the phase current through calibration conversion, computational methods are

$\left\{\begin{array}{c}{I_a}^{\′}=I_a*K_i\\ {I_b}^{\′}=I_b*K_i\\ {I_c}^{\′}=I_c*K_i\end{array}\right.---\left(5\right)$

In above-mentioned formula (5), I _a, I _b, I _cfor the phase current values that the super sampling module of three-phase voltage current gathers, K _ifor calibration with current signal proportionality coefficient, setting method is

K _i=A _i/2 ⁿ(6)

In above formula (6), A _ifor electric current input range.

Power supply instantaneous active power account form is

$p_G=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aGi}}+{U_b}^{\′}{I}_{\mathrm{bGi}}+{U_c}^{\′}{I}_{\mathrm{cGi}})---\left(7\right)$

In formula (7), I _aGi, I _bGi, I _cGi is respectively i bar power feeder a, b, c phase transient current.

Load instantaneous active power account form is

$p_L=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aLi}}+{U_b}^{\′}{I}_{\mathrm{bLi}}+{U_c}^{\′}{I}_{\mathrm{cLi}})---\left(8\right)$

In formula (8), I _aLi, I _bLi, I _cLibe respectively i bar load feeder a, b, c phase transient current.

Referring to Fig. 2, algorithm operating part specifically comprises following step:

First power supply is injected to bus active power sampling p _gwith load absorption bus active power sampling p _lsending into comparator asks difference as lowpass digital filter current input signal.

Lowpass digital filter in S territory transfer function is:

$Y\left(S\right)=\frac{1}{1+\mathrm{TS}}\·E\left(S\right)---\left(9\right)$

In above formula, S is Laplacian; Y is output variable; E is input variable; T is time constant, need set according to smooth effect demand and system configuration.

After discretization, actual execution algorithm is as follows:

$Y\left(k\right)=\frac{T_c}{T_c+T}\·[E\left(k\right)-E(k-1)+Y(k-1)]---\left(10\right)$

T in formula _cfor control cycle, Y (k) is current control cycle output variable, and E (k) is current input variable, and E (k-1) is a upper control cycle input variable, and Y (k-1) is a upper control cycle output.

Lowpass digital filter output Y (k) is current period interconnection active power reference value, by it with current interconnection power output p relatively after, after difference and energy-storage system loss balancing value and a upper cycle energy-storage system active power reference value are added, obtain the order of energy-storage system active power reference value.Control it this instruction is distributed to energy accumulation current converter.

A _uby the specified input voltage U of the super sampling module of embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value is provided by the super sampling module of embedded controller producer; A _iby the specified input current I of the super sampling module of embedded controller _indetermine with current sensor or mutual inductor ratio N, account form is A _i=I _in* N, n value is provided by the super sampling module of embedded controller producer.

More than show and described basic principle of the present invention and principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; that in above-described embodiment and specification, describes just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.

Claims (3)

1. the micro-electrical network based on embedded controller moves a control strategy on the spot, it is characterized in that, specifically comprises following step:

(1) by sampling module, gather phase voltage U _a, U _b, U _cand phase current I _a, I _b, I _c, and gather the three-phase transient current I of every power feeder _aGi, I _bGi, I _cGiand the three-phase transient current I of every load feeder _aLi, I _bLi, I _cLi;

(2) active-power P, power supply instantaneous active power p while calculating in real time interconnection real time instant electric discharge _gwith load instantaneous active power p _l;

(3) by the power supply instantaneous active power p of sampling _gwith load instantaneous active power p _lsend into comparator and ask difference, the current input signal using difference as lowpass digital filter, wherein, power supply instantaneous active power p _ggetting power injection generatrix direction is reference direction, load instantaneous active power p _lgetting outflow generatrix direction is reference direction;

Described lowpass digital filter in S territory transfer function is:

$Y\left(S\right)=\frac{1}{1+\mathrm{TS}}\·E\left(S\right)---\left(9\right)$

Wherein, S is Laplacian, and Y is output variable, and E is input variable, and T is time constant,

After discretization, actual execution algorithm is as follows:

$Y\left(k\right)=\frac{T_c}{T_c+T}\·[E\left(k\right)-E(k-1)+Y(k-1)]---\left(10\right)$

Wherein, T _cfor control cycle, Y (k) is current control cycle output variable, E (k) is current control cycle input variable, E (k-1) is a upper control cycle input variable, Y (k-1) is a upper control cycle output variable, and the current control cycle output variable Y (k) of described lowpass digital filter is the interconnection active power reference value of current control cycle;

(4) described interconnection active power reference value and the real-time instantaneous active power p of current interconnection are sent into comparator and ask difference;

After providing fiducial value the energy-storage system loss balancing value obtaining through on-the-spot actual debugging and a upper control cycle energy-storage system active power reference value to be added difference, Jiang You energy accumulation current converter producer, obtain current control cycle energy-storage system active power reference value, and the order of described current control cycle energy-storage system active power reference value is sent to energy accumulation current converter.

2. the micro-electrical network based on embedded controller according to claim 1 moves control strategy on the spot, it is characterized in that,

Active-power P, power supply instantaneous active power p during described interconnection real time instant electric discharge _gwith load instantaneous active power p _lcomputational methods as follows:

By the phase voltage U gathering _a, U _b, U _cchange line voltage U into _ab, U _bc, U _caafter, then go back to actual phase voltage U _a', U _b', U _c',

Transfer phase voltage to line voltage:

$\left\{\begin{array}{c}{U}_{\mathrm{ab}}=U_a-U_b\\ U_{\mathrm{bc}}=U_b-U_c\\ U_{\mathrm{ca}}=U_c-U_a\end{array}\right.---\left(1\right)$

Transfer line voltage to actual phase voltage again:

$\left\{\begin{array}{c}{U_a}^{\′}=(U_{\mathrm{ab}}-U_{\mathrm{ca}})/3*K_u\\ {U_b}^{\′}=(U_{\mathrm{bc}}-U_{\mathrm{ab}})/3*K_u\\ {U_c}^{\′}=(U_{\mathrm{ca}}-U_{\mathrm{bc}})/3*K_u\end{array}\right.---\left(2\right)$

Wherein, K _ufor voltage, demarcate proportionality coefficient, setting method is

K _u=A _u/2 ⁿ （3）

Wherein, A _ufor voltage input range, n is sample conversion accuracy figure place;

During described interconnection real time instant electric discharge, the account form of active-power P is

p=U _a'I _a'+U _b'I _b'+U _c'I _c' （4）

Wherein, I _a', I _b', I _c' be the phase current through calibration conversion, computational methods are

$\left\{\begin{array}{c}{I_a}^{\′}=I_a*K_i\\ {I_b}^{\′}=I_b*K_i\\ {I_c}^{\′}=I_c*K_i\end{array}\right.---\left(5\right)$

Wherein, K _ifor calibration with current signal proportionality coefficient, setting method is

K _i=A _i/2 ⁿ (6)

Wherein, A _ifor electric current input range;

Described power supply instantaneous active power p _gaccount form be

$p_G=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aGi}}+{U_b}^{\′}{I}_{\mathrm{bGi}}+{U_c}^{\′}{I}_{\mathrm{cGi}})---\left(7\right)$

Wherein, I _aGi, I _bGi, I _cGi is respectively i bar power feeder a, b, c phase transient current;

Described load instantaneous active power p _laccount form be

$p_L=\underset{i=1}{\overset{g}{\mathrm{\Σ}}}({U_a}^{\′}{I}_{\mathrm{aLi}}+{U_b}^{\′}{I}_{\mathrm{bLi}}+{U_c}^{\′}{I}_{\mathrm{cLi}})---\left(8\right)$

Wherein, I _aLi, I _bLi, I _cLibe respectively i bar load feeder a, b, c phase transient current.

3. the micro-electrical network based on embedded controller according to claim 2 moves control strategy on the spot, it is characterized in that,

Described A _uby the specified input voltage U of the super sampling module of embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value is provided by the super sampling module of embedded controller producer;

Described A _iby the specified input current I of the super sampling module of embedded controller _indetermine with current sensor or mutual inductor ratio N, account form is A _i=I _in* N, n value is provided by the super sampling module of embedded controller producer.

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