Improved control of the boost inverter feeding AC loads as ... · Improved control of the boost...

Séminaire du département DO, Axe Energie, LIA MIRC

March 28, 2019

Improved control of the boost inverter feeding AC loads as a part of a hybrid

microgrid

Oswaldo LOPEZ SANTOS, Germain GARCIA

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Outline

1. General description of the research interest.2. MIREDHI-Lab Research Project context for study of microgrids.3. Boost inverter: General description and state-of-the-art.4. Sliding mode control approaches for the boost inverter.5. Proposed improvement.6. Conclusions.

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Improved control of the boost inverter feeding AC loads as a part of a hybrid microgrid

March 28, 2019

1. Context of our research interest

Secondary level control

Primary level control Primary level control Primary level control

DC bus

LVDC busESS (Battery)RES (PV)

DC-DC DC-DC DC-DC Loads


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1. Scientific interest: Control strategies improved performance

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• Efficiency• Simplicity• Flexibility• Modularity• Robustness• Power quality• Reliability• Lifetime


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Control system

Power conversion system

Controlsignals

Input variablesMeasurement

Output variablesMeasurement

Inner variablesmeasurements

𝑷𝒊𝒏 𝑷𝒐𝒖𝒕

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Application of nonlinear control techniques to control switching power convertersintegrating generation and consumption units in microgrids.

SLIDING MODE CONTROL

Analogue electronics Digital electronics

2. Scientific interest: Simplified and reliable implementation

Microgrid


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MIREDHI-Lab ProjectHybrid microgrids for rural applications

2016-2019

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Oswaldo LOPEZ SANTOS, Germain GARCIA, Luis MARTINEZ SALAMERO

Wind generators Grid

Lighting

Electric fence

Micro-irrigation

Microgrid hardwarePower converters and control

Solar panels

Internet access

Basic home equipment

7Minimal composition of the structure of the hybrid microgrid used as demonstrator.


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8Proposed future architecture of the hybrid microgrid used as demonstrator.


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9Hybrid microgrid regarded from the ELVDC bus.


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10Hybrid microgrid regarded from the LVDC bus.


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11Hybrid microgrid regarded from the AC subsystem.


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12Hybrid microgrid regarded from the AC subsystem.


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Boost inverterGeneral description and state-of-the-art

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Boost stage 1 Boost stage 2

Differential load

Boost capability: 𝑉𝑚𝑎𝑥 > 𝑣𝑖𝑛

Operation as bidirectional universal converter: DC-DC, DC-AC.

R. O. Caceres and I. Barbi, "A boost DC-AC converter: analysis, design, and experimentation," in IEEETransactions on Power Electronics, vol. 14, no. 1, pp. 134-141, Jan. 1999.

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Operation coupling switching of both boost stages (Case 1)

𝑢 = 1

𝑆1 = 𝑆4 ⇒ 𝑂𝑁𝑆2 = 𝑆3 ⇒ 𝑂𝐹𝐹

𝑢 = 0

𝑆1 = 𝑆4 ⇒ 𝑂𝐹𝐹𝑆2 = 𝑆3 ⇒ 𝑂𝑁

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March 28, 2019

Operation coupling switching of both boost stages (Case 1)

𝑆𝑙𝑖𝑑𝑖𝑛𝑔 𝑠𝑢𝑟𝑓𝑎𝑐𝑒𝐶𝑜𝑛𝑣𝑒𝑟𝑡𝑒𝑟 𝑚𝑜𝑑𝑒𝑙

𝑆𝑡𝑒𝑎𝑑𝑦 𝑠𝑡𝑎𝑡𝑒 − 𝐻𝑎𝑟𝑚𝑜𝑛𝑖𝑐 𝑏𝑎𝑙𝑎𝑛𝑐𝑒

𝐾 𝜔𝑡 ⇒?

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Control diagram (Case 1)

𝑣𝑟𝑒𝑓 = 𝑉𝑚𝑎𝑥 sin𝜔𝑡 (𝑉)

In a nested loop configuration, the value of K into the sliding surface is given by the outer loop enforcing the desired output voltage. The shape of

capacitor voltages and inductor currents appears naturally as a consequence!

F. Flores-Bahamonde, H. Valderrama-Blavi, J. M. Bosque-Moncusi, G. García and L. Martínez-Salamero,"Using the sliding-mode control approach for analysis and design of the boost inverter," in IET PowerElectronics, vol. 9, no. 8, pp. 1625-1634, June 2016.

𝑣𝑂 = 𝑣𝐶1 − 𝑣𝐶2

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Simulated results (Case 1)

𝑣𝑜

𝑣𝐶1 𝑣𝐶1

𝑖𝐿1𝑖𝐿2

𝑖𝐿1 − 𝑖𝐿2

𝐾 + ∆

𝐾 − ∆

𝑣𝑜 ≈ 311 sin𝜔𝑡 (𝑉) ∆= 6 (𝐴)

𝑇𝐻𝐷 < 1%

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Operation decoupling switching of both boost stages (Case 2)

𝑢1 = 1 ⇒ 𝑆2 ⇒ 𝑂𝑁𝑆1 = 𝑂𝐹𝐹

𝑢1 = 0 ⇒ 𝑆2 ⇒ 𝑂𝐹𝐹𝑆1 = 𝑂𝑁

𝑢2 = 1 ⇒ 𝑆4 ⇒ 𝑂𝑁𝑆3 = 𝑂𝐹𝐹

𝑢2 = 1 ⇒ 𝑆4 ⇒ 𝑂𝐹𝐹𝑆3 = 𝑂𝑁

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March 28, 2019

Operation decoupling switching of both boost stages (Case 2)

𝑆𝑙𝑖𝑑𝑖𝑛𝑔 𝑠𝑢𝑟𝑓𝑎𝑐𝑒𝐶𝑜𝑛𝑣𝑒𝑟𝑡𝑒𝑟 𝑚𝑜𝑑𝑒𝑙

𝑆𝑡𝑒𝑎𝑑𝑦 𝑠𝑡𝑎𝑡𝑒 − 𝐻𝑎𝑟𝑚𝑜𝑛𝑖𝑐 𝑏𝑎𝑙𝑎𝑛𝑐𝑒

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Control diagram (Case 2.1)

𝑣𝑟𝑒𝑓1 = 𝑉𝑑𝑐 + 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 (𝑉)

In a nested loop configuration, the value of 𝑲𝟏 and 𝑲𝟐 into the sliding surfaces is given by the outer loops enforcing the desired waveforms in the

capacitor voltages which in turn define the output voltage!

𝑣𝑟𝑒𝑓2 = 𝑉𝑑𝑐 − 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 (𝑉)

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Simulated results (Case 2.1)

𝑣𝑜 ≈ 311 sin𝜔𝑡 (𝑉)

𝑣𝐶1 ≈ 𝑣𝑟𝑒𝑓1 ≈ 367 − 155 sin𝜔𝑡 (𝑉)∆= 2.5 (𝐴)

𝑣𝑜

𝑣𝐶1 𝑣𝐶1

𝑖𝐿1𝑖𝐿2


𝑇𝐻𝐷 < 1%

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Control diagram (Case 2.2)

𝑣𝑟𝑒𝑓1 = 𝑉𝑑𝑐 + 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 − 𝑉2cos 2𝜔𝑡 (𝑉)

In a nested loop configuration, the value of 𝑲𝟏 and 𝑲𝟐 into the sliding surfaces is given by the outer loops enforcing the desired waveforms in the

capacitor voltages which in turn define the output voltage!

𝑣𝑟𝑒𝑓2 = 𝑉𝑑𝑐 − 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 − 𝑉2cos 2𝜔𝑡 (𝑉)

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March 28, 2019

Simulated results (Case 2.2)

𝑣𝑜 ≈ 311 sin𝜔𝑡 (𝑉)

𝑣𝐶1 ≈ 𝑣𝑟𝑒𝑓1 ≈ 334 − 155 sin𝜔𝑡 − 45 cos 2𝜔𝑡 (𝑉)

∆= 2.5 (𝐴)

𝑣𝑜

𝑣𝐶1 𝑣𝐶1

𝑖𝐿1𝑖𝐿2


𝑇𝐻𝐷 < 1%

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March 28, 2019

Comparison of control approaches regarding gain

𝒗𝑪𝟏𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑜𝑟 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 [𝑉]

𝜔𝑡 = 0𝐺𝑎𝑖𝑛 = 2.51

𝐺𝑎𝑖𝑛 = 1.41

𝐺𝑎𝑖𝑛 = 2.19

𝐺𝑎𝑖𝑛 = 1.87

𝐺𝑎𝑖𝑛 = 3.47

1.41 < 𝐺𝑎𝑖𝑛 < 3.47𝐶𝑎𝑠𝑒 2.1 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑠 ℎ𝑎𝑠 𝑎 ℎ𝑖𝑔ℎ 𝑔𝑎𝑖𝑛 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑚𝑒𝑛𝑡

𝐶𝑎𝑠𝑒 2.1

𝐶𝑎𝑠𝑒 1


𝑣𝑖𝑛 = 150 𝑉

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March 28, 2019

Comparison of control approaches regarding duty cycle

𝑫𝐷𝑢𝑡𝑦 𝑐𝑦𝑐𝑙𝑒

𝐷 = 0.60

𝐷 = 0.50

𝐷 = 0.46

𝐷 = 0.29

0.29 < 𝐷 < 0.60𝑃𝑟𝑜𝑝𝑜𝑠𝑒𝑑 𝑐𝑎𝑠𝑒 𝑐𝑜𝑛𝑠𝑖𝑑𝑒𝑟𝑎𝑏𝑙𝑦 𝑟𝑒𝑑𝑢𝑐𝑒 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝐷


𝐶𝑎𝑠𝑒 1


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March 28, 2019

Comparison of control approaches regarding duty cycle

𝑫𝐷𝑢𝑡𝑦 𝑐𝑦𝑐𝑙𝑒

𝐷 = 0.60

𝐷 = 0.50

𝐷 = 0.46

𝐷 = 0.29


𝐶𝑎𝑠𝑒 1


𝑇ℎ𝑒 𝑛𝑒𝑤 𝑑𝑒𝑔𝑟𝑒𝑒𝑜𝑓 𝑓𝑟𝑒𝑒𝑑𝑜𝑚 𝑖𝑠 𝑉2!

𝑣𝑟𝑒𝑓1 = 𝑉𝑑𝑐 + 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 − 𝑉2cos 2𝜔𝑡 (𝑉)

𝑣𝑟𝑒𝑓2 = 𝑉𝑑𝑐 − 0.5𝑉𝑚𝑎𝑥 sin𝜔𝑡 − 𝑉2cos 2𝜔𝑡 (𝑉)

Conclusions

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1. Boost inverter is a very flexible converter topology which providescapabilities that conventional full-bridge cannot provide being a potentialcandidate for microgrids.

2. All compared sliding mode control approaches for the boost invertershows a high quality in the output voltage.

3. The proposed control technique increases the efficiency of the boostinverter at expenses of some additional computations.


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Immediate work

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1. A boost inverter prototype is being tested to verify the presentedcomparison of sliding-mode based control techniques.

2. Operation of the proposed control and new proposals are beingevaluated for converter feeding nonlinear loads.


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𝐻𝐴𝑅𝐷 𝑊𝑂𝑅𝐾 𝑇𝑂 𝐷𝑂 𝐴 𝐶𝑂𝑀𝑃𝐿𝐸𝑇𝐸 𝐸𝐹𝐹𝐼𝐶𝐼𝐸𝑁𝐶𝑌𝐴𝑁𝐴𝐿𝑌𝑆𝐼𝑆 𝑊𝐼𝑇𝐻 𝐸𝑋𝑃𝐸𝑅𝐼𝑀𝐸𝑁𝑇𝐴𝐿 𝑉𝐴𝐿𝐼𝐷𝐴𝑇𝐼𝑂𝑁

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Acknowledgments

Students involved in the work team of the MIREDHI-Lab project- David Alejandro Zambrano Prada (Master on Control Engineering)- María Camila Merchán Riveros (Master on Control Engineering)- Diego Fernando Salazar D’Antonio (Master on Control Engineering)- Sebastián Tilaguy Lezama (Young researcher D+Tec Group)- Alejandro Rubio Reinoso (Electronics Engineering)- Yeison Alejandro Aldana Rodríguez (Electronics Engineering)- Jhonathan Julián Gallego Rojas (Electronics Engineering)- María Claudia Salas Castaño (Electronics Engineering)- Alejandra Quijano Saavedra (Electronics Engineering)- Efrén Leonardo Sosa Bonilla (Electronics Engineering)- Angelica Henao Castaño (Mechanics Enginnering)- Nicolás Alejandro López Varón (Electronics Engineering)- Santiago Rodríguez Clinger (Electronics Engineering)

Images at the top of the slides:

D. Roberts & A. Chang. Meet the microgrid, the technology poised to transform electricity.


March 28, 2019

Thank you very much!

[email protected]

Improved control of the boost inverter feeding AC loads as ... · Improved control of the boost...

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