CN109190202A - A kind of piezoelectric energy collecting device impedance modeling method based on artificial neural network - Google Patents

A kind of piezoelectric energy collecting device impedance modeling method based on artificial neural network Download PDF

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Publication number
CN109190202A
CN109190202A CN201810931373.9A CN201810931373A CN109190202A CN 109190202 A CN109190202 A CN 109190202A CN 201810931373 A CN201810931373 A CN 201810931373A CN 109190202 A CN109190202 A CN 109190202A
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neural network
artificial neural
meas
esr
esc
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马建国
赵升
傅海鹏
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Tianjin University
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Tianjin University
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/30Circuit design
    • G06F30/36Circuit design at the analogue level
    • G06F30/367Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06NCOMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
    • G06N3/00Computing arrangements based on biological models
    • G06N3/02Neural networks
    • G06N3/08Learning methods

Abstract

The piezoelectric energy collecting device impedance modeling method based on artificial neural network that the invention discloses a kind of: the N number of frequency point of impedance analyzer uniform scanning, measurement piezoelectric energy collecting device ESR in Freq frequency range are usedMEASAnd ESCMEAS;According to ESRMEASAnd ESCMEAS, obtain Qs、Ωs、Ωp、ρeff, calculate Lm、Rm、Cm、ESRBVD、ESCBVD;It to sum up obtains N group data and is divided into two groups of odd even, odd number group is artificial neural network training data, and even number set is artificial neural network test data;Artificial neural network training is completed, the biasing and weight of optimal hidden layer number, hidden layer neuron number, neuron are obtained;Trained artificial neural network is tested, ESR is exportedANNAnd ESCANN, so that ESRANNAnd ESRMEASAnd ESCANNAnd ESCMEASRelative error meet the requirements.The invention enables device resistance modeling accuracies to be increased dramatically.

Description

A kind of piezoelectric energy collecting device impedance modeling method based on artificial neural network
Technical field
The invention belongs to piezoelectric vibration energy assembling spheres, and more specifically, it relates to one kind to be based on artificial neural network Piezoelectric energy collecting device impedance modeling method.
Background technique
Converting electric energy for the mechanical vibrational energy in natural environment by piezoelectric energy collecting device is microsensor Node power supply is a hot research direction.Common piezoelectric energy collecting device has cantilever beam structure, in practical applications Its main limitation is: when the vibration frequency in environment deviates the intrinsic frequency of piezoelectric energy collecting device, piezoelectric energy The output power of collecting device can sharply decline, to limit the wideband application of piezoelectric energy collecting device.Biasing overturning electricity Output electric current and output voltage phase relation of the road as a kind of adjustable piezoelectric energy collecting device of nonlinear technology, thus Improve the output power outside device intrinsic frequency.
Voltage overturning efficiency has a major impact the collection power of piezoelectric energy collecting device in biasing reverse circuit, In circuit simulation modeling, the EFFICIENCY PREDICTION deviation of very little, which will lead to predicted collection power, very big error.Therefore it is being based on In the Earlier designs for biasing the energy collection circuit of turnover technology, voltage overturns the accurate prediction of efficiency for accurate estimating system Collected energy is particularly significant.The calculating of voltage overturning efficiency depends primarily on the equivalent series electricity of piezoelectric energy collecting device Resistance and series capacitance.And the equivalent series resistance and series capacitance of piezoelectric energy collecting device and biasing reverse circuit resonance frequency It is related.Therefore voltage overturning efficiency accurately is predicted to depend on to piezoelectric energy collecting device equivalent series resistance and series electrical The Accurate Model of appearance.
Traditional piezoelectric energy collecting device impedance modeling method has Mason model, Butterworth-van Dyke (BVD) model and modified Butterworth-van Dyke (MBVD) model.These analytic modell analytical model complexities not once There is closed solution.Mason model is made of and imaginary without actual physical meaning comprising one complicated transmission line structure Negative resistance, so that solution equivalent series resistance and series capacitance are relatively difficult.Although and BVD and MBVD model is by simple lump Parametric device composition, so that solution equivalent series resistance and series capacitance are easier, but is to solve for value and actual measured value Differ larger.
Summary of the invention
Purpose of the invention is to overcome the shortcomings in the prior art, for existing traditional piezoelectric energy collecting device Equivalent circuit impedance existing for model models inaccurate problem, proposes a kind of piezoelectric energy collector based on artificial neural network Part impedance modeling method is crossed and combines artificial neural network and traditional BVD device equivalent-circuit model, so that device resistance is built Mould precision is increased dramatically.
The purpose of the present invention is what is be achieved through the following technical solutions.
Piezoelectric energy collecting device impedance modeling method based on artificial neural network of the invention, comprising the following steps:
Step 1 measures each frequency point in biasing reverse circuit resonance frequency using the N number of frequency point of impedance analyzer uniform scanning The actual measurement impedance data of piezoelectric energy collecting device within the scope of rate Freq: actual measurement equivalent series resistance ESRMEASWith actual measurement equivalent string Join capacitor ESCMEAS
Step 2 extracts the parameter of BVD equivalent-circuit model as artificial neural network input data: equivalent according to surveying Series resistance ESRMEASWith actual measurement equivalent series capacitance ESCMEAS, obtain quality factor qs, series resonance frequency Ωs, parallel resonance Frequency omegap, equivalent coupled coefficient ρeff, and then calculate inductance Lm, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model output equivalent series capacitance ESCBVD
Step 3 to sum up obtains N group data, including actual measurement impedance data and artificial neural network input data, by this N group Data are divided into two groups of odd even, training data of the odd number group as artificial neural network, survey of the even number set as artificial neural network Try data;
Step 4 completes the training of artificial neural network by MATLAB, obtains optimal hidden layer number, hidden layer mind Biasing and weight through first number, neuron, obtain trained artificial neural network;
Step 5 tests trained artificial neural network, output equivalent series resistance ESRANNWith it is equivalent Series capacitance ESCANN, calculate ESRANNAnd ESRMEASAnd ESCANNAnd ESCMEASRelative error, if relative error is met the requirements Modeling process is then completed, step 5 is repeated if relative error cannot be met the requirements, until relative error meets the requirements and completes Modeling process.
Inductance L described in step 2m, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model Output equivalent series capacitance ESCBVDIt is calculated as follows:
Ωs=1/ (LmCm)
ρeff=Cm/C0
QssLm/Rm
Wherein, ΩsIt is series resonance frequency;QsIt is quality factor, according to actual measurement equivalent series resistance ESRMEASExperiment curv Obtain Qs=f0/ Δ f, f0It is actual measurement equivalent series resistance ESRMEASThe centre frequency of experiment curv, Δ f are actual measurement equivalent series Resistance ESRMEASThe three dB bandwidth of experiment curv;ρeffIt is equivalent coupled coefficient, passes throughIt is calculated, Ωp It is parallel resonance frequency;C0It is the internal stationary capacitor of piezoelectric energy collecting device;ω is biasing reverse circuit resonance frequency Angular frequency corresponding to Freq.
Compared with prior art, the beneficial effects brought by the technical solution of the present invention are as follows:
The present invention combines artificial neural network and traditional BVD device equivalent-circuit model, so that device resistance models Precision is increased dramatically, and has very accurate impedance prediction result in wider frequency range.The artificial mind of comparison display The result and experimental measurements predicted through network model are coincide substantially.
Detailed description of the invention
Fig. 1 is the piezoelectric energy collecting device impedance model schematic diagram the present invention is based on artificial neural network;
Fig. 2 is BVD equivalent-circuit model schematic diagram of the present invention;
Fig. 3 is artificial neural network structure's schematic diagram of the present invention;
Fig. 4 is training and the testing process schematic diagram of artificial nerve network model of the present invention;
Fig. 5 is that BVD model exports ESR, artificial neural network in 2600Hz-3600Hz resonant frequency range of the present invention Export ESR and experiment measurement ESR curve graph;
Fig. 6 is that BVD model exports ESC, artificial neural network in 2600Hz-3600Hz resonant frequency range of the present invention Export ESC and experiment measurement ESC curve graph.
Specific embodiment
The invention will be further described with reference to the accompanying drawing.
Piezoelectric energy collecting device impedance modeling method based on artificial neural network of the invention, as shown in Figure 1, packet It includes: Conventional wisdom model and artificial neural network.The Conventional wisdom model provides rough piezoelectricity energy as priori knowledge The impedance model of collecting device is measured, and artificial neural network can learn the non-linear input and output of any complexity by training Relationship.Empirical model can be reduced into artificial neural network training time and required training data in conjunction with artificial neural network, The modeling result of degree of precision is obtained simultaneously.
The Conventional wisdom model uses BVD equivalent-circuit model, as shown in Figure 2.In the BVD model, inductance LmGeneration The effective mass of table device, resistance RmRepresent the mechanical damping of device, CmRepresent the mechanical stiffness of device.Capacitor C0Represent device Internal stationary capacitor.The piezoelectric energy collecting device impedance expression are as follows:
Wherein, ω is angular frequency corresponding to biasing reverse circuit resonance frequency Freq.
Artificial neural network structure input data, output data and neuron as shown in figure 3, be made of.The nerve net Network input data is biasing reverse circuit resonance frequency Freq, series resonance frequency Ωs, quality factor qs, equivalent coupled coefficient ρeff, device internal stationary capacitor C0, BVD equivalent-circuit model output equivalent series resistance ESRBVDWith BVD equivalent circuit mould Type output equivalent series capacitance ESCBVD.Neural network output data is equivalent series resistance ESRANNAnd equivalent series capacitance ESCANN.The neural network is three layer perceptron structure, is made of input layer, output layer and hidden layer.The neuron of hidden layer Quantity can obtain optimal setting by repeatedly training and test.Number needed for data needed for artificial neural network training or test According to comprising artificial neural network input data and actual measurement impedance data: actual measurement equivalent series resistance ESRMEASWith capacitor ESCMEAS。 Excitation function used in neuron is Sigmoid function.
Piezoelectric energy collecting device impedance modeling method based on artificial neural network of the invention, as shown in figure 4, including Following steps:
Step 1 is measured each frequency point and is overturn in a certain range of biasing using the N number of frequency point of impedance analyzer uniform scanning The actual measurement impedance data of piezoelectric energy collecting device within the scope of circuit resonant frequencies Freq: actual measurement equivalent series resistance ESRMEASWith Survey equivalent series capacitance ESCMEAS
Step 2 extracts the parameter of BVD equivalent-circuit model as artificial neural network input data: equivalent according to surveying Series resistance ESRMEASWith actual measurement equivalent series capacitance ESCMEAS, obtain quality factor qs, series resonance frequency Ωs, parallel resonance Frequency omegap, equivalent coupled coefficient ρeff, and then calculate inductance Lm, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model output equivalent series capacitance ESCBVD
Wherein, inductance Lm, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model output equivalent Series capacitance ESCBVDIt is calculated as follows:
Ωs=1/ (LmCm) (2)
ρeff=Cm/C0 (3)
QssLm/Rm (4)
Wherein, ΩsIt is series resonance frequency, the maximum value of corresponding piezoelectric energy collecting device admittance;QsIt is quality factor, According to actual measurement equivalent series resistance ESRMEASExperiment curv obtains Qs=f0/ Δ f, f0It is actual measurement equivalent series resistance ESRMEASMeasurement The centre frequency of curve, Δ f are actual measurement equivalent series resistance ESRMEASThe three dB bandwidth of experiment curv;ρeffIt is equivalent coupled system Number, can pass throughIt is calculated, ΩpIt is parallel resonance frequency, corresponding piezoelectric energy collecting device impedance Maximum value;C0It is the internal stationary capacitor of piezoelectric energy collecting device.
Step 4 to sum up obtains N group data, including actual measurement impedance data and artificial neural network input data, by this N group Data are divided into two groups of odd even, training data of the odd number group as artificial neural network, survey of the even number set as artificial neural network Try data;
Step 5 completes the training of artificial neural network by MATLAB, and training algorithm can use Quasi-Newton iterative method, The biasing and weight of optimal hidden layer number, hidden layer neuron number, neuron are obtained, trained artificial neuron is obtained Network;
Step 6 is different from the new data of training data by one group, carries out to trained artificial neural network Test, output equivalent series resistance ESRANNWith equivalent series capacitance ESCANN, calculate ESRANNAnd ESRMEASAnd ESCANNWith ESCMEASRelative error, complete modeling process if relative error is met the requirements, weighed if relative error cannot be met the requirements Multiple step 5 completes modeling process until relative error is met the requirements.
Embodiment:
The experimental provision of specific embodiment includes: impedance analyzer and piezoelectric energy collecting device Mide V25W.It is specific real Applying and biasing reverse circuit resonance frequency Freq range in example is 2600Hz-3600Hz.Use impedance analyzer uniform scanning 504 Frequency point measures and surveys equivalent series resistance ESR within the scope of 2600Hz-3600HzMEASWith actual measurement equivalent series capacitance ESCMEAS.Root According to measured actual measurement equivalent series resistance ESRMEASThe available Q of experiment curvs=f0/ Δ f=26.9;According to measured Survey equivalent series resistance ESRMEASWith actual measurement equivalent series capacitance ESCMEASCalculating finds the admittance of piezoelectric energy collecting device most Parallel resonance frequency corresponding to the maximum value of big value corresponding series resonance frequency Ω s and piezoelectric energy collecting device impedance Rate Ωp;Pass through formulaρ is calculatedeff=0.025.Low frequency Static Electro is measured using impedance analyzer Hold C0=191nF.L is calculated according to formulam=7.20 × 10-1H、Cm=4.78 × 10-9F、Rm=456.6 Ω.Basis simultaneously BVD model output equivalent series resistance ESR can be calculated in formulaBVDWith BVD model output equivalent series capacitance ESCBVD.It is comprehensive On obtain 504 groups of data, including 1. artificial neural network input datas: biasing reverse circuit resonance frequency Freq, series resonance Frequency omegas, quality factor qs, equivalent coupled coefficient ρeff, device internal stationary capacitor C0, BVD equivalent-circuit model output etc. Imitate series resistance ESRBVDWith BVD equivalent-circuit model output equivalent series capacitance ESCBVD;2. experiment actual measurement impedance data: actual measurement Equivalent series resistance ESRMEASWith actual measurement equivalent series capacitance ESCMEAS
504 groups of data obtained by above-mentioned calculating are divided into two groups of odd even, training data of the odd number group as artificial neural network, Test data of the even number set as artificial neural network.The training that artificial neural network is completed by MATLAB, obtains optimal The biasing and weight of hidden layer number, hidden layer neuron number, neuron.Again to trained artificial neural network into Row test, so that ESRANNAnd ESRMEASAnd ESCANNAnd ESCMEASRelative error it is sufficiently small.Fig. 5 show BVD model, The equivalent series resistance ESR curve of artificial nerve network model and experiment measurement.Fig. 6 shows BVD model, artificial neural network The equivalent series capacitance ESC curve of model and experiment measurement.The result and reality that comparison display artificial nerve network model is predicted Test magnitude coincide substantially.
Although function and the course of work of the invention are described above in conjunction with attached drawing, the invention is not limited to Above-mentioned concrete function and the course of work, the above mentioned embodiment is only schematical, rather than restrictive, ability The those of ordinary skill in domain under the inspiration of the present invention, is not departing from present inventive concept and scope of the claimed protection situation Under, many forms can be also made, all of these belong to the protection of the present invention.

Claims (2)

1. a kind of piezoelectric energy collecting device impedance modeling method based on artificial neural network, which is characterized in that including following Step:
Step 1 measures each frequency point in biasing reverse circuit resonance frequency using the N number of frequency point of impedance analyzer uniform scanning The actual measurement impedance data of piezoelectric energy collecting device within the scope of Freq: actual measurement equivalent series resistance ESRMEASWith actual measurement equivalent series Capacitor ESCMEAS
Step 2 extracts the parameter of BVD equivalent-circuit model as artificial neural network input data: according to actual measurement equivalent series Resistance ESRMEASWith actual measurement equivalent series capacitance ESCMEAS, obtain quality factor qs, series resonance frequency Ωs, parallel resonance frequency Ωp, equivalent coupled coefficient ρeff, and then calculate inductance Lm, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model output equivalent series capacitance ESCBVD
Step 3 to sum up obtains N group data, including actual measurement impedance data and artificial neural network input data, by this N group data It is divided into two groups of odd even, training data of the odd number group as artificial neural network, test number of the even number set as artificial neural network According to;
Step 4 is completed the training of artificial neural network by MATLAB, obtains optimal hidden layer number, hidden layer neuron The biasing and weight of number, neuron, obtain trained artificial neural network;
Step 5 tests trained artificial neural network, output equivalent series resistance ESRANNAnd equivalent series Capacitor ESCANN, calculate ESRANNAnd ESRMEASAnd ESCANNAnd ESCMEASRelative error, it is complete if relative error is met the requirements At modeling process, step 5 is repeated if relative error cannot be met the requirements, until relative error meets the requirements and completes to model Process.
2. the piezoelectric energy collecting device impedance modeling method according to claim 1 based on artificial neural network, special Sign is, inductance L described in step 2m, resistance Rm, resistance Cm, BVD model output equivalent series resistance ESRBVD, BVD model it is defeated Equivalent series capacitance ESC outBVDIt is calculated as follows:
Ωs=1/ (LmCm)
ρeff=Cm/C0
QssLm/Rm
Wherein, ΩsIt is series resonance frequency;QsIt is quality factor, according to actual measurement equivalent series resistance ESRMEASExperiment curv obtains Qs=f0/ Δ f, f0It is actual measurement equivalent series resistance ESRMEASThe centre frequency of experiment curv, Δ f are actual measurement equivalent series resistances ESRMEASThe three dB bandwidth of experiment curv;ρeffIt is equivalent coupled coefficient, passes throughIt is calculated, ΩpIt is simultaneously Join resonance frequency;C0It is the internal stationary capacitor of piezoelectric energy collecting device;ω is biasing reverse circuit resonance frequency Freq institute Corresponding angular frequency.
CN201810931373.9A 2018-08-15 2018-08-15 A kind of piezoelectric energy collecting device impedance modeling method based on artificial neural network Pending CN109190202A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110135010A (en) * 2019-04-23 2019-08-16 天津大学 The design method of RF power amplifier intervalve matching circuit is instructed using modeling

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Publication number Priority date Publication date Assignee Title
CN101776862A (en) * 2008-05-29 2010-07-14 通用电气公司 System and method for advanced condition monitoring of an asset system
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Title
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110135010A (en) * 2019-04-23 2019-08-16 天津大学 The design method of RF power amplifier intervalve matching circuit is instructed using modeling

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Application publication date: 20190111