Self-Powered Adaptive Switched Architecture Storage for Ultra-Capacitors

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https://hal.laas.fr/hal-01754705

Submitted on 11 Apr 2018

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Self-Powered Adaptive Switched Architecture Storage for Ultra-Capacitors

Firdaous El Mahboubi, Marise Bafleur, Vincent Boitier, Jean-Marie Dilhac

To cite this version:

Firdaous El Mahboubi, Marise Bafleur, Vincent Boitier, Jean-Marie Dilhac. Self-Powered Adaptive Switched Architecture Storage for Ultra-Capacitors . 16th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2016), Dec 2016, Paris, France. 2016. �hal-01754705�

(2)

Laboratoire conventionné avec l’Université Fédérale Toulouse Midi-Pyrénées LAAS-CNRS

/ Laboratoire d’analyse et d’architecture des systèmes du CNRS

C1 C2 C3 C4

V

_C4

C4 C2 C3

C1

V

_C4

C1 C2

C3 C4

Firdaous EL MAHBOUBI, Marise BAFLEUR, Vincent BOITIER, Jean Marie DILHAC

LAAS-CNRS, Université Toulouse, CNRS, INSA, UPS, Toulouse, France

felmahbo@laas.fr

Self-adaptive Architecture

CONTEXT: Autonomous battery-free wireless sensor node

 Experimental results

Energy harvester simulated by a Thévenin generator

E _th =5V, R _th =1kΩ, R

_LOAD

=1kΩ, C=100mF, C _fix =400mF, V

_SH

=2V, V

_SL

=1V

Acknowledgments

This work is carried out within the framework of the European project SMARTER funded by the CHIST-ERA program, “Green ICT, towards Zero Power ICT”.

 Charge profile:

 The S configuration allows for a fast charging and startup (low Ceq).

 The P configuration allows for the storage of a large amount of energy (high Ceq).

 Discharge profile:

 The S configuration allows a maximum energy usage rate in the case of a system powered by an energy harvesting source.

Both structures are identical, they have the same number of SCs, switches and configurations (S, SP, P). However, they differ in the SP configuration.

 Balancing currents, simulation result of the worst case, High current in second switching SP→P (low current in first switching S→SP)

Perspectives

Silicon integration of the self-powered and adaptive storage.

The principle of this structure is to change the value of the total storage capacity according to the state of charge/discharge, to satisfy the objectives: fast charging time with a low capacitance Ceq=C/N (series configuration), maximization of stored energy with Ceq=CN (parallel* configuration).

Each of the two types of adaptive structures consists of 4 identical supercapacitors (SC) + 9 switches + 3 Schottky diodes for structure B, allowing three possible configurations: Series (S), series-parallel (SP) and parallel (P), (The diodes allow a default serial structure).

Analysis of the two self-adaptives architectures

C1 C3

C4 C2

For these simulation, we model each switch by a resistor, and the ultra-capacitor by a capacitor in series with a resistor (C=100mF±20%, ESR=0.08Ω, R

_switch

=0.4Ω).

Self-powered and adaptive storage system Objectives

• Coupling energy harvesting & storage on supercapacitor (SC)

• Adaptive storage for early startup at charging (low capacitance value) and maximization of stored energy (high capacitance),

• Autonomy of the system and maximum energy usage rate.

Self-adaptive architectures under study

Structure A

C

₂

=C

_min

V+

C

₃

=C

_max

C

₄

=C

_max

C

₁

=C

_min

Structure B

Structure A Structure B

 Impact of the dispersion in capacitance values on losses (worst case)

Conclusion

 Low losses  balancing circuit not necessary

 Structure B exhibits lower balancing currents

Signal processing

Wireless communication Energy management DC

power generator

Adaptive supercapacitor

storage RF

Energy Transducer

&

Sensing

Input Output

Tolerance range

C=100mF±20%

C1 (F)

C2 (F)

C3 (F)

C4 (F)

E _MAX loss

Structure A 0.12 0.08 0.08 0.12 2.08%

Structure B 0.08 0.08 0.12 0.12 2.16%

C

₂

=C

_min

V+

C

₁

=C

_max

C

₃

=C

_min

C

₄

=C

_max

P SP S

1V 30s

Discharge phase

C4

V V V V

C3 C2 +

0 40 80 100 140

0 2 4

Voltage across ultra-capacitors (V)

Time (s)

V_SH

V_SL

C

_Adaptive

PZT

FB Rectifier

Logic control

V^C4

LOAD

Vdd

U1 U2

Structure B

P SP

S 1V

50s

Chargephase

C4

V V V V

C3 C2 +

0 40 80 100 140

0 2 4

Voltage across ultra-capacitors (V)

Time (s) V_SH V_SL

Prototype of the autonomous adaptive storage system

Structure A Structure B

Logic gates

CMOS Switches

Comparators

Capacitor

Charge Discharge

E/C

_fixed

(J/F)

E/C

_variable

(J/F)

E/C

_fixed

(J/F)

E/C

_variable

(J/F)

Theoretical

calculation 12.25 12.25 11.05 12.18

Measurement 12.46 12.89 11.01 12.23

Losses Delivered energy rate

1.7% 5.2% 10%

V_C4 V_C3 V_C2 V+

V+ V_C2

V_C3 V_C4

V_C2

V+ V_C3 V_C4

C

var

0 0.5 1 1.5 2 2.5

50 100 150 200 250 300 350 400 450 500 550

Time(s)

Voltage(V)

C fixed

configuration SP

Emax loss expressed in % of the stored energy

Measurement and calculation of losses

Source and load modeled by a constant current source

I=±3.5mA,

V

+MAX_CHARGE

=5V,

V

+MIN_DISCHARGE

=1.55V, C

_variable

=100mF,

C

_fixed

=400mF

Diagram for the system startup time supplied by self powered and adaptive structure or by a single

capacitance

Time(min)

Voltage across a single capacitance(V)

Cfixed

Time(min)

Voltage across ultra-capacitors(V)

Cvar

0.0s 0.1s 0.2s 0.3s 0.4s 0.5s 0.6s 0.7s 0.8s 0.9s 1.0s 1.1s 1.2s 1.3s 1.4s -200mA

-160mA -120mA -80mA -40mA 0mA 40mA 80mA 120mA 160mA

200mA Î(C1) Î(C2) Î(C3) Î(C4)

Temps (S)

Courent (A)

I(C1): Le courant du condensateur C1 I(C2): Le courant du condensateur C2 I(C3): Le courant du condensateur C3

I(C4): Le courant du condensateur C4

0.0s 0.1s 0.2s 0.3s 0.4s 0.5s 0.6s 0.7s 0.8s 0.9s 1.0s 1.1s 1.2s 1.3s 1.4s -15mA

-12mA -9mA -6mA -3mA 0mA 3mA 6mA 9mA 12mA

15mA Î(C1) Î(C2) Î(C3) Î(C4)

Temps (S)

Courent (A)

I(C1): Le courant du condensateur C1 I(C2): Le courant du condensateur C2 I(C3): Le courant du condensateur C3

I(C4): Le courant du condensateur C4

Self-Powered Adaptive Switched Architecture Storage for Ultra-Capacitors

Self-Powered Adaptive Switched Architecture Storage for Ultra-Capacitors

Laboratoire conventionné avec l’Université Fédérale Toulouse Midi-Pyrénées LAAS-CNRS

/ Laboratoire d’analyse et d’architecture des systèmes du CNRS

C1 C2 C3 C4

V

C4 C2 C3

C1

V

C1 C2

C3 C4

Firdaous EL MAHBOUBI, Marise BAFLEUR, Vincent BOITIER, Jean Marie DILHAC

LAAS-CNRS, Université Toulouse, CNRS, INSA, UPS, Toulouse, France

felmahbo@laas.fr

Self-adaptive Architecture

CONTEXT: Autonomous battery-free wireless sensor node

 Experimental results

Energy harvester simulated by a Thévenin generator

E th =5V, R th =1kΩ, R

=1kΩ, C=100mF, C fix =400mF, V

=2V, V

=1V

Acknowledgments

This work is carried out within the framework of the European project SMARTER funded by the CHIST-ERA program, “Green ICT, towards Zero Power ICT”.

 Charge profile:

 The S configuration allows for a fast charging and startup (low Ceq).

 The P configuration allows for the storage of a large amount of energy (high Ceq).

 Discharge profile:

 The S configuration allows a maximum energy usage rate in the case of a system powered by an energy harvesting source.

Both structures are identical, they have the same number of SCs, switches and configurations (S, SP, P). However, they differ in the SP configuration.

 Balancing currents, simulation result of the worst case, High current in second switching SP→P (low current in first switching S→SP)

Perspectives

Silicon integration of the self-powered and adaptive storage.

The principle of this structure is to change the value of the total storage capacity according to the state of charge/discharge, to satisfy the objectives: fast charging time with a low capacitance Ceq=C/N (series configuration), maximization of stored energy with Ceq=C*N (parallel configuration).

Each of the two types of adaptive structures consists of 4 identical supercapacitors (SC) + 9 switches + 3 Schottky diodes for structure B, allowing three possible configurations: Series (S), series-parallel (SP) and parallel (P), (The diodes allow a default serial structure).

Analysis of the two self-adaptives architectures

C1 C3

C4 C2

For these simulation, we model each switch by a resistor, and the ultra-capacitor by a capacitor in series with a resistor (C=100mF±20%, ESR=0.08Ω, R

=0.4Ω).

Self-powered and adaptive storage system Objectives

• Coupling energy harvesting & storage on supercapacitor (SC)

• Adaptive storage for early startup at charging (low capacitance value) and maximization of stored energy (high capacitance),

• Autonomy of the system and maximum energy usage rate.

Self-adaptive architectures under study

Structure A

Structure A

C

=C

V+

C

=C

C

=C

C

=C

Structure B

Structure A Structure B

 Impact of the dispersion in capacitance values on losses (worst case)

Conclusion

 Low losses  balancing circuit not necessary

 Structure B exhibits lower balancing currents

Signal processing

Wireless communication Energy management DC

power generator

Adaptive supercapacitor

storage RF

Energy Transducer

&

Sensing

Input Output

Tolerance range

C=100mF±20%

C1 (F)

C2 (F)

C3 (F)

C4 (F)

E MAX loss

Structure A 0.12 0.08 0.08 0.12 2.08%

Structure B 0.08 0.08 0.12 0.12 2.16%

E _th =5V, R _th =1kΩ, R

=1kΩ, C=100mF, C _fix =400mF, V

The principle of this structure is to change the value of the total storage capacity according to the state of charge/discharge, to satisfy the objectives: fast charging time with a low capacitance Ceq=C/N (series configuration), maximization of stored energy with Ceq=CN (parallel* configuration).

E _MAX loss