CN103701118B - A kind of micro-capacitance sensor based on embedded controller runs control strategy on the spot - Google Patents

Abstract

The invention discloses a kind of micro-capacitance sensor based on embedded controller and run control strategy on the spot, gather the transient current of phase voltage, phase current and every bar power supply and load feeder; Calculate the real-time instantaneous active power of interconnection, power supply instantaneous active power and load instantaneous active power; Power supply is injected the sampling of bus active power to sample with load absorption bus active power and send into comparator and ask difference; The current control period output variable of lowpass digital filter is the interconnection active power reference value of current control period; Interconnection active power reference value and the real-time instantaneous active power of current interconnection are sent into comparator and asks difference; After difference, energy-storage system loss balancing value and a upper control cycle energy-storage system active power reference value are added, obtain current control period energy-storage system active power reference value, and this reference value is sent to energy accumulation current converter.Fast response time of the present invention, electric energy can discharge by secondary, can be widely used in all kinds of micro-grid system.

Description

A kind of micro-capacitance sensor based on embedded controller runs control strategy on the spot

Technical field

The present invention relates to a kind of micro-capacitance sensor based on embedded controller and run control strategy on the spot, belong to intelligent micro-grid technical field.

Background technology

At present, intelligent micro-grid technical field is generally by the level and smooth microgrid dominant eigenvalues of mode of the adjustable heating power load of adjustment.

The method exist response speed slow, absorb electric energy and be difficult to secondary release, reduce the shortcoming of utilization of power quality, and lack general, cannot be applied in the microgrid lacking adjustable heating power load.

Summary of the invention

For the deficiency that prior art exists, the object of the invention is to provide a kind of micro-capacitance sensor based on embedded controller and runs control strategy on the spot, fast response time, and electric energy can discharge by secondary, can be widely used in all kinds of micro-grid system.

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

A kind of micro-capacitance sensor based on embedded controller of the present invention runs control strategy on the spot, specifically comprises following step:

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

(2) active-power P, power supply instantaneous active power p during real-time calculating 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, using the current input signal of 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 period output variable, E (k) is current control period input variable, E (k-1) is a upper control cycle input variable, Y (k-1) is the interconnection active power reference value of current control period for a upper control cycle output variable, current control period output variable Y (k) of lowpass digital filter;

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

By difference, fiducial value will be provided by energy accumulation current converter producer and debug after the energy-storage system loss balancing value and a upper control cycle energy-storage system active power reference value addition obtained through on-the-spot reality, obtain current control period energy-storage system active power reference value, and the order of current control period 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 gathered _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',

Phase voltage is transferred 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 demarcates 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-th 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-th load feeder a, b, c phase transient current.

Above-mentioned A _usampling module nominal input voltage U is surpassed by embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value surpasses sampling module producer by embedded controller provides; A _ithe specified input current I of sampling module is surpassed by embedded controller _indetermine with current sensor or mutual inductor ratio N, account form is A _i=I _in* N, n value surpasses sampling module producer by embedded controller provides.

The active power that the present invention achieves microgrid interconnection by the mode of real-time digital filtering is level and smooth, overcomes slow by adjustable heating power load responding, that electric energy is difficult to secondary release shortcoming, can be widely used in all kinds of micro-grid system; Simultaneously, under adopting this control strategy mode service conditions, energy-storage system overall average power output (electric energy) in unit long time period is 0, namely under can meeting grid-connected conditions, energy-storage system is while automatic smoothing microgrid interconnection power output, carrying capacity stablizing in unit long time period.

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

The technological means realized for making the present invention, creation characteristic, reaching object and effect is easy to understand, below in conjunction with embodiment, setting forth the present invention further.

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

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

(2) intermediate layer: the capital equipment in intermediate layer is embedded controller, engineer carries out field adjustable by industrial computer or individual PC to intermediate layer program.The real time information of each distributed power 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 that telemechanical interface is for scheduling or distant place centralized control center 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 see Fig. 1.

Method of the present invention is specifically applied to and is in bulk power grid and the microgrid of net state.Method of the present invention comprises data acquisition and procession part and algorithm execution part.

Data acquisition and procession part specifically comprises following step:

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

Adopt the wiring of three-phase four-wire system Gather and input in this device, directly gather the instantaneous value of the voltage between a, b, c three-phase and neutral point, going back to phase voltage again after need changing the phase voltage directly gathered into line voltage can be used for controlling calculation.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 being surpassed the phase voltage value that sampling module gathers by 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 demarcates 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 three-phase voltage current surpasses the phase current values of sampling module collection, 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-th 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-th load feeder a, b, c phase transient current.

See Fig. 2, algorithm execution part specifically comprises following step:

First power supply is injected bus active power sampling p _gto sample p with load absorption bus active power _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 according to smooth effect demand and system configuration settings.

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 period 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 exports Y (k) i.e. current period interconnection active power reference value, after it being compared with current interconnection power output p, difference obtains the order of energy-storage system active power reference value with energy-storage system loss balancing value and a upper cycle energy-storage system active power reference value after being added.Control it and this instruction is distributed to energy accumulation current converter.

A _usampling module nominal input voltage U is surpassed by embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value surpasses sampling module producer by embedded controller provides; A _ithe specified input current I of sampling module is surpassed by embedded controller _indetermine with current sensor or mutual inductor ratio N, account form is A _i=I _in* N, n value surpasses sampling module producer by embedded controller provides.

More than show and describe general 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; what describe in above-described embodiment and specification 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.Application claims protection range is defined by appending claims and equivalent thereof.

Claims (3)

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

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

(2) the real-time instantaneous active power p of interconnection, power supply instantaneous active power p is calculated in real time _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, using the current input signal of 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:

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

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

(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;

By difference, fiducial value will be provided by energy accumulation current converter producer and debug after the energy-storage system loss balancing value and a upper control cycle energy-storage system active power reference value addition obtained through on-the-spot reality, obtain current control period energy-storage system active power reference value, and the order of described current control period energy-storage system active power reference value is sent to energy accumulation current converter.

2. the micro-capacitance sensor based on embedded controller according to claim 1 runs control strategy on the spot, it is characterized in that,

The real-time instantaneous active power p of described interconnection, power supply instantaneous active power p _gwith load instantaneous active power p _lcomputational methods as follows:

By the phase voltage U gathered _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',

Phase voltage is transferred to line voltage:

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

Transfer line voltage to actual phase voltage again:

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

Wherein, K _ufor voltage demarcates 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;

The account form of the real-time instantaneous active power p of described interconnection 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

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

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

Described load instantaneous active power p _laccount form be

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

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

3. the micro-capacitance sensor based on embedded controller according to claim 2 runs control strategy on the spot, it is characterized in that,

Described A _usampling module nominal input voltage U is surpassed by embedded controller _indetermine with voltage sensor or mutual inductor ratio M, account form is A _u=U _in* M, n value surpasses sampling module producer by embedded controller provides;

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