CN103490764B - Scei interface circuit - Google Patents

Abstract

The invention discloses SCEI interface circuit.External mechanical vibrations can be converted into electric energy and store in energy-storage travelling wave tube by this interface circuit efficiently, and the electric energy stored in energy-storage travelling wave tube can be that microelectronic component provides enough electric energy, thus meets the power demands of microelectronic component.This interface circuit has two significant advantages compared with other interface circuit, first show that the regenerative power of this interface circuit is more than Parallel-SSHI interface circuit maximum regeneration power, Parallel-SSHI interface circuit regenerative power in current energy regenerating interface circuit is maximum, and regenerative power changes with load change；Next shows that the regenerative power of this interface circuit is unrelated with being connect load, namely is all optimum to any load regenerative power, and this characteristic is the most particularly important.

Description

SCEI interface circuit

Technical field

The present invention relates to Energy Recovery Technology based on piezoelectric effect, be specifically related to a kind of novel energy and reclaim interface Circuit.

Background technology

Due to wireless technology and the progress of micro electro mechanical system (MEMS) technology, to portable electric appts and wireless senser The power demands of power supply unit also grows with each passing day, and these equipment are mostly based on lithium battery at present.Due to life-span institute Limit, lithium battery in use need change battery, but in some cases change battery be also a cost very High and unrealistic work.So, carry out new wireless energy supply technology research oneself become the task of top priority.Base Energy-recuperation system in piezoelectric effect is that the mechanical vibrational energy being widely present by nature is converted to electric energy, this energy Amount recovery system has that output is big, electronic device does not produce electromagnetic interference, volume is little, be prone to device The advantages such as miniaturization.At present, the research work of energy-recuperation system based on piezoelectric effect is at home and abroad in Exploratory stage, substantial amounts of theory and test problem is still had to need to solve, the energy regenerating interface circuit of highly effective In current patent and document also little, common interface circuit have standard interface, SECE interface, Parallel-SSHI interface, Series-SSHI interface.Standard interface circuit is simple and is easily achieved, but reclaims merit Rate is low and can change with load change；The regenerative power of SECE interface circuit is standard interface in theory Four times and will not with load change；The regenerative power of Parallel-SSH and Series-SSHI interface circuit is relatively SECE interface is bigger but can change with the change of load.These interface circuits can not meet the most far away energy and return The needs of receipts system, it is still desirable to constantly research and develop the interface circuit of highly effective.

Therefore, need a kind of new technical scheme to solve the problems referred to above.

Summary of the invention

The invention discloses a kind of SCEI interface circuit, English full name is Synchronous Charge Extraction and Inversion Interface, i.e. piezoelectric energy recovery interface circuit.This interface circuit and existing Interface circuit is compared, and not only regenerative power is big and regenerative power does not changes with load change.

SCEI interface circuit includes following structure: by piezoelectric patches, inductance L₁, electrical switch S₁The L of composition₁C_P Oscillating circuit, the full-bridge rectification electric bridge D being made up of four diodes₁, by inductance L₂, switch S₂, afterflow two Pole pipe D₂, filter capacitor C_rThe voltage raising and reducing transducer of composition, extraneous load R_L；L₁C_POscillating circuit is successively Connect full-bridge rectification electric bridge D₁, voltage raising and reducing transducer and external load R_L。

Wherein inductance L₁With switch S₁After series connection in parallel with piezoelectric patches, and the two ends of piezoelectric patches and full-bridge rectification electricity Bridge D₁Input 2 and input 3 be connected；Inductance L in voltage raising and reducing transducer₂One end connects full-bridge rectification Electric bridge D₁Outfan 1 and the other end and switch S₂It is in series, switches S₂One end connect full-bridge rectification Electric bridge D₁Outfan 4 and the other end and inductance L₂It is in series；And diode D₂Positive pole and inductance L₂, open Close S₂Series connection midpoint is connected, diode D₂Negative pole and filter capacitor C_rPositive pole is connected；Filter capacitor C_rNegative pole With full-bridge rectification electric bridge D₁Outfan 1 be connected；External load R_LWith filter capacitor C_rIn parallel；

SCEI interface circuit carries out twice energy regenerating within each mechanical vibration cycle, and each energy regenerating can It is divided into the upset of Energy extraction, voltage, open circuit three phases.Maximum in mechanical vibration displacement changes to Energy extraction, voltage that minimum comprised in this half mechanical vibration cycle overturn, open circuit three phases divides It is not:

(1) in the Energy extraction stage: when mechanical vibration displacement reaches maximum, piezoelectric patches voltage V reaches maximum Value VP, switchs S₂Guan Bi, the electric energy being now stored on piezoelectric patches is to inductance L₂Transfer, piezoelectric patches voltage V with Decline.When dropping to γ V_PTime, switch S₂Disconnecting, wherein γ is L₁C_PThe upsetting ratio of oscillating circuit, 0<γ<1.It is transferred to inductance L₂In electric energy pass through sustained diode subsequently₂Transfer to filter capacitor C_rWith Load R_LIn.

(2) the voltage upset stage: switch S₂Disconnect moment, switch S₁Guan Bi, now inductance L₁, switch S₁, piezoelectric patches will form L₁C_POscillation circuit.As half L₁C_PAfter cycle of oscillation terminates, switch S₁Disconnect, Owing to there is energy loss, piezoelectric patches voltage V is by the γ V before vibrating_PUpset is the-γ after vibration²V_P。

(3) the open circuit stage: as above-mentioned switch S₁After disconnection, the electric current I that piezoelectric patches flows out is zero, Hereafter piezoelectric patches voltage V gradually becomes big to opposite direction along with vibration displacement, when mechanical vibration displacement reach negative When being worth greatly, the voltage V of piezoelectric patches reaches negative maximum-V_P, now half vibration period terminates.

Above-mentioned L₁C_PReverse circuit, it is characterised in that inductance parameters L₁L should be made₁C_PThe vibration of oscillating circuit Cycle less than the mechanical vibration cycle 1/20 or less.Additionally, inductance L should be made₁Quality factor to the greatest extent may be used Can be big to reclaim more energy.Switch S₁Select fast response time, the electrical switch of low on-resistance.

Above-mentioned full-bridge rectification electric bridge D₁, it is characterised in that diode selection switching speed is fast, forward conduction voltage drop The diode that little, reverse cut-off current is little.

Above-mentioned voltage raising and reducing transducer, it is characterised in that the switch S of this voltage raising and reducing transducer₂Should be at piezoelectric patches Voltage V reaches Guan Bi during extreme value, disconnects when piezoelectric patches voltage V drops to γ times of extreme value, and wherein γ is L₁C_PThe upsetting ratio of oscillation circuit, 0 < γ < 1.Additionally, high-quality-factor inductance L should be selected₂And make Switch S₂ON time less than the vibration period 1/20 or less；Filter capacitor C_rCapacity should meet R_LC_r> this condition of 5T, wherein T is the mechanical vibration cycle.

Beneficial effects of the present invention:

The present invention is a kind of novel energy regenerating interface circuit, and this interface circuit has compared with existing interface circuit Two remarkable advantages.First show that the regenerative power of this interface circuit is more than Parallel-SSHI interface circuit Big regenerative power, regenerative power maximum is also in current energy regenerating interface circuit for Parallel-SSHI interface circuit And regenerative power but changes with load change.Next regenerative power showing this interface circuit and load nothing Closing, this characteristic is the most particularly important.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of SCEI interface circuit.

Fig. 2 is the piezoelectric patches voltage oscillogram of SCEI interface circuit and corresponding switch controlling signal.In figure U is mechanical vibration displacement, and V is piezoelectric patches voltage, s₁And s₂Respectively switch S₁And S₂Control signal.

Fig. 3 is under constant exciting misalignment, standard interface, SECE, Series-SSHI, Parallel-SSHI Regenerative power-load R with SCEI interface circuit_LTheory relation figure.

Fig. 4 is the artificial circuit figure of SCEI interface circuit.

Fig. 5 be use electronic simulation software Multisim obtain standard interface, SECE, Series-SSHI, Parallel-SSHI and SCEI interface circuit regenerative power-load R_LThe simulation result of relation.

Detailed description of the invention

Below in conjunction with the accompanying drawings and specific embodiment, it is further elucidated with the present invention, it should be understood that these embodiments are only used for The present invention is described rather than limits the scope of the present invention, after having read the present invention, those skilled in the art Amendment to the various equivalent form of values of the present invention all falls within the application claims limited range.

Referring to shown in Fig. 1, SCEI interface circuit includes following structure: by piezoelectric patches, inductance L₁, electronics Switch S₁The L of composition₁C_POscillating circuit, the full-bridge rectification electric bridge D being made up of four diodes₁, by inductance L₂, switch S₂, sustained diode₂, filter capacitor C_rThe voltage raising and reducing transducer of composition, extraneous load R_L； L₁C_POscillating circuit is sequentially connected with full-bridge rectification electric bridge D₁, voltage raising and reducing transducer and external load R_L。

Above-mentioned L₁C_PReverse circuit, it is characterised in that inductance parameters L₁L should be made₁C_PThe vibration of oscillating circuit Cycle less than the mechanical vibration cycle 1/20 or less.Additionally, inductance L should be made₁Quality factor to the greatest extent may be used Can be big to reclaim more energy.Switch S₁Select fast response time, the electrical switch of low on-resistance.

Above-mentioned full-bridge rectification electric bridge D₁, it is characterised in that diode selection switching speed is fast, forward conduction voltage drop The diode that little, reverse cut-off current is little.

Above-mentioned voltage raising and reducing transducer, it is characterised in that the switch S of this voltage raising and reducing transducer₂Should be at piezoelectric patches Voltage V reaches Guan Bi during extreme value, disconnects when piezoelectric patches voltage V drops to γ times of extreme value, and wherein γ is L₁C_PThe upsetting ratio of oscillation circuit, 0 < γ < 1.Additionally, high-quality-factor inductance L should be selected₂And make Switch S₂ON time less than the vibration period 1/20 or less；Filter capacitor C_rCapacity should meet R_LC_r> this condition of 5T, wherein T is the mechanical vibration cycle.

Piezoelectric patches voltage waveform and corresponding switch controlling signal s during SCEI interface circuit work₁、s₂State can Seeing Fig. 2, this interface circuit carries out twice energy regenerating within each mechanical vibration cycle, and each energy regenerating can It is divided into the upset of Energy extraction, voltage, open circuit three phases.Illustrate the these three stage separately below and be given What the theoretical derivation of SCEI interface circuit regenerative power, is finally construed to and drops to γ V at piezoelectric patches voltage V_P Shi Kaiguan S₂Disconnect.

In the Energy extraction stage, when mechanical vibration displacement reaches maximum, piezoelectric patches voltage V reaches maximum V_P, switch S₂Guan Bi, the electric energy being now stored on piezoelectric patches is to inductance L₂Transfer, piezoelectric patches voltage V with Decline, it is assumed that V drops to V_MTime S₂Disconnecting, now the electric energy on piezoelectric patches stops to L₂Transfer, It is transferred to inductance L₂In electric energy will pass through sustained diode₂Transfer to filter capacitor C_rWith load R_LIn. Therefore, the ENERGY E reclaimed in the Energy extraction stage_HFor:

$E_H=(\frac{1}{2}{C}_P{V}_P^2-\frac{1}{2}{C}_P{V}_M^2)\&CenterDot;\mathrm{\&eta;}$

Wherein C_PFor the clamped capacitance of piezoelectric patches, η is the efficiency of voltage raising and reducing transducer.

Switch S₂Disconnect moment, switch S₁Guan Bi, SCEI circuit enters the voltage upset stage, through half L₁C_PS after cycle of oscillation₁Disconnecting, piezoelectric patches voltage V is by the V before vibrating_MAfter upset is for vibration V_m, V_mAnd V_MContrary sign.Owing to there is energy loss, V_mAbsolute value be less than V_MAbsolute value.To this end, Introducing this concept of upsetting ratio γ, its expression formula is:

$\mathrm{\&gamma;}=-\frac{V_m}{V_M},(0<\mathrm{\&gamma;}<1)$

The relation that can be obtained piezoelectric patches voltage V and electric current I and vibration displacement u by standard piezoelectric equation is:

$I=\mathrm{\&alpha;}\stackrel{\&CenterDot;}{u}-C_P\stackrel{\&CenterDot;}{V}$

Wherein α is the power factor of piezoelectric patches, C_PClamped capacitance for piezoelectric patches.

After the voltage upset stage terminates, SCEI enters the open circuit stage, and piezoelectric patches voltage is along with vibration position Shifting to negative direction become larger, when mechanical vibration displacement reaches negative maximum, the voltage V of piezoelectric patches reaches Negative maximum-V_P.Owing in the open circuit stage, the electric current flowing out piezoelectric patches is zero, and above formula becomes In the time domain in open circuit stage, its integration can be obtained:

$V_m+V_P=\frac{2\mathrm{\&alpha;}}{C_P}{U}_M$

Order:

V_M=x V_P

More than simultaneous various can obtain the ENERGY E that piezoelectric patches reclaimed within half vibration period_HLetter about x Number expression formula is:

$E_H=\frac{2{\mathrm{\&alpha;}}^2{U}_M^2}{C_P}\&CenterDot;\frac{1-x^2}{{(1-\mathrm{\&gamma;}x)}^2}\&CenterDot;\mathrm{\&eta;}$

Owing to carrying out twice energy regenerating, the therefore regenerative power of SCEI interface circuit in a vibration period P is:

$P=\frac{E_H}{T/2}=\frac{2{\mathrm{\&omega;\&alpha;}}^2{U}_M^2}{{\mathrm{\&pi;C}}_P}\&CenterDot;\frac{1-x^2}{{(1-\mathrm{\&gamma;}x)}^2}\&CenterDot;\mathrm{\&eta;}$

Wherein T is the mechanical vibration cycle, and ω is mechanical vibration angular frequency, U_MAmplitude for mechanical vibration displacement.

Under constant exciting misalignment, namely mechanical vibration displacement amplitude U_MWhen keeping constant, SCEI returns Receiving only x in power P expression formula is variable, and this regenerative power P exists maximum.OrderCan try to achieve:

x_opt=γ

Now maximum regeneration power P_MAXFor:

$P_{MAX}=\frac{2{\mathrm{\&omega;\&alpha;}}^2{U}_M^2}{{\mathrm{\&pi;C}}_P(1-{\mathrm{\&gamma;}}^2)}\&CenterDot;\mathrm{\&eta;}$

From x_opt=γ is it will be seen that work as V_M=γ V_PTime, namely in the Energy extraction stage, when piezoelectric patches voltage from Maximum V_PDrop to γ V_PShi Kaiguan S₂Disconnecting, now the regenerative power of SCEI is maximum.Merit is reclaimed from maximum Rate P_MAXExpression formula understands regenerative power and the load resistance R of SCEI interface circuit_LIt doesn't matter, namely SCEI Regenerative power does not changes with load change.

Fig. 3 give when upsetting ratio γ=0.5, voltage raising and reducing transducer efficiency eta=0.8 time standard interface, SECE, Series-SSHI, Parallel-SSHI and SCEI theoretical recovery merit under constant exciting misalignment Rate and load R_LGraph of a relation.For making these figures not affected by energy-recuperation system inherent parameters, to Excellent load and maximum regeneration power are respectively relative to the optimal load of standard interface and maximum regeneration power is carried out Normalized.

Be given below electronic simulation software Multisim Plays interface, SECE, Series-SSHI, The regenerative power simulation result of Parallel-SSHI and SCEI interface circuit.

According to the theory of G.K.Ottman et al., piezoelectric patches can being subject to a sinusoidal current source parallel piezoelectric sheet Folder electric capacity C_PRepresenting, the frequency of this sinusoidal current source is identical with mechanical oscillation frequencies, its amplitude I_M=2 π f α U_M, wherein f is mechanical oscillation frequencies, and α is the power factor of piezoelectric patches, U_MFor mechanical vibration Displacement amplitude.In order to ensure that five kinds of interface circuits meet constant exciting displacement condition, as long as arranging them there is phase Same current source amplitude I_M?.In artificial circuit, the clamped capacitance C of piezoelectric patches_P=50nF, machinery shakes Dynamic frequency f=50Hz, current source amplitude I_M=100uA.The circuit simulation figure of SCEI interface circuit is shown in Fig. 4. The standard interface that finally gives, SECE, Series-SSHI, Parallel-SSHI, the returning of SCEI interface circuit Receive power about load R_LSimulation result see Fig. 5.

Claims (4)

1. a SCEI interface circuit, it is characterised in that including: by piezoelectric patches, inductance L₁, switch S₁The L of composition₁C_POscillating circuit, the full-bridge rectification electric bridge D being made up of four diodes₁, by inductance L₂, switch S₂, sustained diode₂, filter capacitor C_rThe voltage raising and reducing transducer of composition, external load R_L；L₁C_POscillating circuit is sequentially connected with full-bridge rectification electric bridge D₁, voltage raising and reducing transducer and external load R_L；

Wherein inductance L₁With switch S₁After series connection in parallel with piezoelectric patches, and the two ends of piezoelectric patches and full-bridge rectification electric bridge D₁Input 2 and input 3 be connected；Inductance L in voltage raising and reducing transducer₂One end connects full-bridge rectification electric bridge D₁Outfan 1 and the other end and switch S₂It is in series, switchs S₂One end connect full-bridge rectification electric bridge D₁Outfan 4 and the other end and inductance L₂It is in series；And diode D₂Positive pole and inductance L₂, switch S₂Series connection midpoint is connected, diode D₂Negative pole and filter capacitor C_rPositive pole is connected；Filter capacitor C_rNegative pole and full-bridge rectification electric bridge D₁Outfan 1 be connected；External load R_LWith filter capacitor C_rIn parallel；

Twice energy regenerating is completed within each mechanical vibration cycle, every time energy regenerating is divided into the upset of Energy extraction, voltage, open circuit three phases, and Energy extraction that the maximum in mechanical vibration displacement changes to comprise in this half mechanical vibration cycle of minimum, voltage upset, open circuit three phases are respectively as follows:

(1) in the Energy extraction stage: when mechanical vibration displacement reaches maximum, piezoelectric patches voltage V reaches maximum V_P, now control signal makes switch S₂Guan Bi, the electric energy being stored on piezoelectric patches is to inductance L₂Transfer, piezoelectric patches voltage V declines therewith；When dropping to γ V_PTime, switch S₂Disconnecting, wherein γ is L₁C_PThe upsetting ratio of oscillating circuit, 0 < γ < 1；It is transferred to inductance L₂In electric energy pass through sustained diode subsequently₂Transfer to filter capacitor C_rWith load R_LIn；

(2) the voltage upset stage: switch S₂Disconnect moment, switch S₁Guan Bi, now inductance L₁, switch S₁, piezoelectric patches will form L₁C_POscillation circuit；After half cycle of oscillation terminates, switch S₁Disconnecting, owing to there is energy loss, piezoelectric patches voltage V is by the γ V before vibrating_PUpset is the-γ after vibration²V_P；

(3) the open circuit stage: as above-mentioned switch S₁After disconnection, the electric current I that piezoelectric patches flows out is zero, and hereafter piezoelectric patches voltage V is gradually big to negative direction change along with vibration displacement, and when mechanical vibration displacement reaches negative maximum, the voltage V of piezoelectric patches reaches negative maximum-V_P, now half vibration period terminates.

SCEI interface circuit the most according to claim 1, it is characterised in that inductance L₁Parameter should make L₁C_PThe cycle of oscillation of oscillating circuit less than the mechanical vibration cycle 1/20 or less；Switch S₁Select fast response time, the electrical switch of low on-resistance.

SCEI interface circuit the most according to claim 1, it is characterised in that rectifier bridge D₁The diode that switching speed is fast, forward conduction voltage drop is little, reverse cut-off current is little selected by middle diode.

SCEI interface circuit the most according to claim 1, it is characterised in that the switch S of voltage raising and reducing transducer₂Closing when piezoelectric patches voltage V reaches extreme value, disconnect when piezoelectric patches voltage V drops to γ times of extreme value, wherein γ is L₁C_PThe upsetting ratio of oscillating circuit, 0 < γ < 1；Inductance L₂Select high-quality-factor inductance and make to switch S₂ON time less than the mechanical vibration cycle 1/20 or less；Filter capacitor C_rCapacity should meet R_LC_r> this condition of 5T, wherein T is the mechanical vibration cycle.