Michael McIntyre EPIC 2018

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Advanced Control Systems for Grid Connected Inverter Applications

Michael L. McIntyre, Ph.D., PE. Associate Professor, Electrical and Computer Engineering

13th Annual University of Pittsburg - Electric Power Industry Conference

10/15/2018

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Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Introduction • Single and Three Phase Voltage Sources Inverters have a wide range of applications in modern Power Systems – – – –

Renewable Integration Energy Storage FACTS Devices Active Rectification

• Low Steady State Error • Transient Performance

– Fast Dynamic Response

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Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters My Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Existing Control Schemes • Circuit – Modulation - Control • 1Φ & 3Φ Phase Circuit Topologies – Additional Switching Leg for Three Phase

• Bidirectional Power Flow • Modulation Schemes allow for proper DC Bus Utilization – Unipolar vs. SVM

• Control Real and Reactive Power

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Current Control • Grid current is controlled to regulate Active and Reactive power. – Control Objective đ?‘’đ?‘’đ?‘ƒđ?‘ƒ ≜ đ?‘ƒđ?‘ƒâˆ— − đ?‘ƒđ?‘ƒ & đ?‘’đ?‘’đ?‘„đ?‘„ ≜ đ?‘„đ?‘„∗ − đ?‘„đ?‘„

• Focus on Inertia emulations • Standards require grid tied systems to preserve ďż˝ đ?œ”đ?œ”, đ?œƒđ?œƒ). grid quality of voltage waveform (đ?‘‰đ?‘‰, • THDi < 5% for EN61000-3-2 đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ??żđ??ż + đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; = đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘? − đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘”đ?‘”đ?‘”đ?‘”đ?‘” đ?‘‘đ?‘‘đ?‘‘đ?‘‘ 6

đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘? ≜ đ??ˇđ??ˇđ?‘‰đ?‘‰đ?‘‘đ?‘‘đ?‘‘đ?‘‘−đ?‘™đ?‘™đ?‘™đ?‘™đ?‘™đ?‘™đ?‘™đ?‘™

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Current Control • Use of rotating (αβ) and stationary(dq) reference frames are utilized for single and three phase systems. Feed-Forward Loop

Modulation Scheme

• GI(s) takes various forms

– PI Control: Shortcomings for due poor disturbance rejection and leads to SSE and power factor issues – PR Control: Uses frequency matching to increase controller gain to improve performance.

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Voltage Control • For voltage forming applications, control scheme takes on a cascaded approach

• Inner Current Loop

– Manage and limit output current

• Outer Voltage Loop

– Manage voltage waveform

• Third Loop Determines Grid Parameters 8

ďż˝ ďż˝ đ?œ”đ?œ”, – (đ?‘‰đ?‘‰, ďż˝ đ?œƒđ?œƒ)

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Grid Synchronization • Establishing Grid Parameters – – – –

Voltage Magnitude Current Magnitude Grid Frequency Grid Phase

ďż˝ đ?œ”đ?œ”, Ě‚ (đ?‘‰đ?‘‰, ďż˝ đ?œƒđ?œƒ)

• IEEE 1547 in packs Grid Synchronization Function • Typically implemented with a Feedback System (Observer) known as Phase Locked Loop

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Existing Control Schemes

Example Control Diagram for Renewable Integration with Grid Notice: PR, PLL, and MPPT 10

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Grid Interface Requirements of the PV System • Quality, Safety & Reliability • IEEE 1547 (<= 10 MVA) • Grid Support • FERC Order 661-A (20+ MW wind farms) • Low-voltage ride through (LVRT) capability • Power factor: +/- 0.95 • Reactive power support • Operation Communication • Monitoring (>=250kVA or aggregated) • SCADA (MW-level) • Dispatchability • Required for large DGs 11

• •

UL 1741, 2nd ed., Nov 7, 2005 Clause 46.1.1 - A utility-interactive inverter and interconnection system equipment (ISE) shall comply with IEEE 1547, and IEEE 1547.1. 10/15/2018

Existing Control Schemes Islanding Detection in the Grid-connected PV System

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Existing Control Schemes Supervisory Level Control

>1 min.

Power Input

Power Export

Load Leveling

Secondary Level Control

~1 sec.

Frequency Regulation

Voltage Stability

Primary Level Control

<1 msec.

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Current Control

Voltage Control

Grid Sync.

Island Detection

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Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Model Based Approach • Typical Electromechanical System Electrical Dynamics

u

��̇ = ��(��, ��, ��)

Mechanical Dynamics

y

��̇ = ��(��, ��)

x

• Classical Control Systems Solutions – Linearization of g(x,y,u) and f(x,y) – Apply linear methods u

��̇ = ��(��, ��, ��)

y

��̇ = ��(��, ��)

x

Linear Controller

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Obstacles to Increased Performance ďƒ˜ System model often contains hard nonlinearities

u

ďƒ˜ Parameters in the model are usually unknown

u

ďƒ˜ Actuator dynamics cannot be neglected

u

ďƒ˜ System states are difficult or costly to measure 16

u

��̇ = ��(��, ��, ��)

��̇ =? (��, ��, ��)

sat(u)

y

y

��̇ = ��(��, ��, ��)

��̇ = f(��, ��, ��)

đ?‘Ľđ?‘ĽĚ‡ = đ?’ˆđ?’ˆ(đ?‘Ľđ?‘Ľ, đ?‘Śđ?‘Ś)

?

��̇ =? (��, ��)

y

đ?‘Ľđ?‘ĽĚ‡ = đ?’ˆđ?’ˆ(đ?‘Ľđ?‘Ľ, đ?‘Śđ?‘Ś)

��̇ = g(��, ��) 10/15/2018

x

x

x

?

Uncertain Math Model Approach

Research Solution

Advanced Control Design Techniques

Real-time Hardware/Software

• Nonlinear Lyapunov-Based Techniques Provide y u ��̇ =? (��, ��, ��) – Controllers designed for the full-order nonlinear models Nonlinear Nonlinear Parameter Controller – Adaptive update laws for on-line estimation Estimator of unknown parameters – Observers or filters for state measurement replacement ? u ��̇ = ��(��, ��, ��) – Analysis that predicts system performance Nonlinear Nonlinear by providing envelopes for the transient Controller Observer response 17

New Controller/ Observer Solutions

��̇ =? (��, ��)

��̇ = f(��, ��)

x

x

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Control Design/Implementation Cycle Testbed Construction

Interface and Safety Issues

Sensors: Encoders, Force Sensor, Camera Actuators: Motors, Electromagnets, Speakers

Signal Conditioning Power Electronic Interfacing HV/LV Interfacing, Comm.

Electronic Compatibility

Mathematical Model

NI Compact RIO/Embedded (encoders, D/A, A/D, digital I/O)

Software Development Matlab/Simulink/RealTime NI-Labview RT PLECS

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PDE-ODE model (flexible systems) ODE model (rigid systems)

Master Thesis Students

Data Acquisition

Real-Time OS, Driver Interface, Data Handling

Physics-Based Models

Control Objective

PhD Students Coding the Control Algorithm

Problem Formulation Tracking, Setpoint Parametric Uncertainty Bounded Disturbance Unmeasurable Signals

Stability Analysis

Control Design

Lyapunov Techniques Simulation Studies Model-Based, Adaptive, Robust 10/15/2018

Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Research Application Areas

Nonlinear Control and Estimation Schemes

Controls for FACTS Devices

Electric Machinery and Drives

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Electrical Energy Systems

Grid Connected Inverters with Loads

Demand Side Management for Smart Grids 10/15/2018

Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

10/15/2018

3φ Current Control Single-Stage Three-Phase Grid-Connected Photovoltaic Systems with Maximum Power Point Tracking and Active and Reactive Power Control Based on Nonlinear Control Renewable Integrations

Controller 1

Controller 2

Dynamic System Equations Control Signals ����′ (��) and ����′ (��):

đ?‘…đ?‘… đ?‘‘đ?‘‘đ?‘‘đ?‘‘′ 1 đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? − đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘” đ??źđ??źđ?‘‘đ?‘‘̇ = − đ??źđ??źđ?‘‘đ?‘‘ + đ??żđ??ż đ??żđ??ż đ??żđ??ż đ?‘‘đ?‘‘đ?‘žđ?‘žâ€˛ đ?‘…đ?‘… 1 đ??źđ??źđ?‘žđ?‘žĚ‡ = − đ??źđ??źđ?‘žđ?‘ž + đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? − đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘” đ??żđ??ż đ??żđ??ż đ??żđ??ż ′

′

̇ = − đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ??źđ??źđ?‘‘đ?‘‘ − đ?‘‘đ?‘‘đ?‘žđ?‘ž đ??źđ??źđ?‘žđ?‘ž + 1 đ??źđ??źđ?‘?đ?‘?đ?‘?đ?‘? đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ??śđ??ś

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đ??śđ??ś

đ??śđ??ś

đ?œ”đ?œ”đ?œ”đ?œ” đ??źđ??ź đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ?‘žđ?‘ž đ?œ”đ?œ”đ?œ”đ?œ” đ?‘‘đ?‘‘đ?‘žđ?‘žâ€˛ = đ?‘‘đ?‘‘đ?‘žđ?‘ž − đ??źđ??ź đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ?‘‘đ?‘‘

����′ = ���� +

P. R. Rivera, M. L. McIntyre, M. Mohebbi, and J. Latham, “Single-Stage Three-Phase Grid-Connected Photovoltaic System with Maximum Power Tracking and Active and Reactive Power Control based on Nonlinear control,� in Proc. of Energy Conversion Congress and Exposition, ECCE, October, 2017, pp. 1-7

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Single-Stage Three-Phase Grid-Connected Photovoltaic ‌‌.. Objectives

A single-stage three-phase grid-connected PV system with Lyapunov-based nonlinear control is proposed: ďƒ˜To achieve MPOP regardless of atmospheric conditions ďƒ˜ To control the Active, Reactive Power, & Unity Power factor on the grid side. Control Development The objective is to design đ?‘‘đ?‘‘đ?‘‘đ?‘‘′ (đ?‘Ąđ?‘Ą) and đ?‘‘đ?‘‘đ?‘žđ?‘žâ€˛ (đ?‘Ąđ?‘Ą) such that:

đ??źđ??źđ?‘‘đ?‘‘ (đ?‘Ąđ?‘Ą) → đ??źđ??źđ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘ (đ?‘Ąđ?‘Ą) and đ??źđ??źđ?‘žđ?‘ž đ?‘Ąđ?‘Ą → đ??źđ??źđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘ž đ?‘Ąđ?‘Ą as t → ∞

thus controlling the Active, Reactive Power & Unity Power factor on the grid side. The control law must also ensure that đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? (đ?‘Ąđ?‘Ą) → đ?‘‰đ?‘‰đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; (đ?‘Ąđ?‘Ą) as đ?‘Ąđ?‘Ą → ∞ to achieve MPPT.

����′

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đ??żđ??ż đ?‘…đ?‘… 1 ̇ = −đ??žđ??žđ?‘‘đ?‘‘ đ?‘’đ?‘’đ?‘‘đ?‘‘ + đ??źđ??źđ?‘‘đ?‘‘ + đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘” + đ??źđ??źđ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ??żđ??ż đ??żđ??ż đ??żđ??ż đ?‘…đ?‘… ̇ đ?‘‘đ?‘‘đ?‘žđ?‘žâ€˛ = −đ??žđ??žđ?‘žđ?‘ž đ?‘’đ?‘’đ?‘žđ?‘ž + đ??źđ??źđ?‘žđ?‘ž + đ??źđ??źđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘ž đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ??żđ??ż

̇ đ??źđ??źđ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘ = đ??žđ??žđ?‘žđ?‘ž đ?‘’đ?‘’đ?‘žđ?‘ž −

đ??źđ??źđ?‘žđ?‘ž

đ??źđ??źđ?‘‘đ?‘‘

đ??źđ??źđ?‘žđ?‘ž

đ??źđ??źđ?‘‘đ?‘‘

+ đ??žđ??žđ?‘Łđ?‘Ł đ?‘’đ?‘’đ?‘Łđ?‘Ł

̇ đ??źđ??źđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘ž −

đ??źđ??źđ?‘žđ?‘ž2

đ?‘…đ?‘… đ??żđ??ż đ??źđ??źđ?‘‘đ?‘‘

đ??śđ??ś đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ??żđ??ż đ??źđ??źđ?‘‘đ?‘‘

+

đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ??źđ??źđ?‘?đ?‘?đ?‘?đ?‘?

+đ??žđ??žđ?‘‘đ?‘‘ đ?‘’đ?‘’đ?‘‘đ?‘‘ −

đ??żđ??żđ??źđ??źđ?‘‘đ?‘‘ đ?‘…đ?‘… đ??źđ??ź đ??żđ??ż đ?‘‘đ?‘‘

P. R. Rivera, M. L. McIntyre, M. Mohebbi, and J. Latham, “Single-Stage Three-Phase Grid-Connected Photovoltaic System with Maximum Power Tracking and Active and Reactive Power Control based on Nonlinear control,� in Proc. of Energy Conversion Congress and Exposition, ECCE, October, 2017, pp. 1-7

−

−

đ??śđ??ś đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ?‘‰đ?‘‰Ě‡ đ??żđ??ż đ??źđ??źđ?‘‘đ?‘‘ đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; 1 đ?‘‰đ?‘‰ đ??żđ??ż đ?‘”đ?‘”đ?‘”đ?‘”

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Single-Stage Three-Phase Grid-Connected Photovoltaic ‌‌.. Instantaneous Circuit Simulation

Fig. 6 PV and Ideal Power

Fig. 12 Grid voltage and current

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Fig. 13 Transient response of the grid current at t=0.4 seconds

Fig. 10 đ??źđ??źđ?‘‘đ?‘‘ , đ??źđ??źđ?‘žđ?‘ž , and references current

Fig. 16 Active and Reactive power of the grid

P. R. Rivera, M. L. McIntyre, M. Mohebbi, and J. Latham, “Single-Stage Three-Phase Grid-Connected Photovoltaic System with Maximum Power Tracking and Active and Reactive Power Control based on Nonlinear control,� in Proc. of Energy Conversion Congress and Exposition, ECCE, October, 2017, pp. 1-7

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Nonlinear Control for Single-Stage, Single-Phase GridConnected Photovoltaic Systems Objectives

A single-stage Single-phase grid-connected PV system with Lyapunov-based nonlinear control is proposed: ďƒ˜To achieve MPOP regardless of atmospheric conditions ďƒ˜ To control the Active, Reactive Power, & Unity Power factor on the grid side. ďƒ˜Minimize Double Line Frequency Ripple through Control Trajectory Development đ?‘‘đ?‘‘đ?‘–đ?‘–đ?‘Žđ?‘Ž = −đ?‘…đ?‘…đ?‘–đ?‘–đ?‘Žđ?‘Ž + đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘?đ?‘?đ?‘?đ?‘? − đ?‘Łđ?‘Łđ?‘”đ?‘”đ?‘”đ?‘” đ??żđ??ż đ?‘‘đ?‘‘đ?‘‘đ?‘‘

đ??śđ??ś

đ?‘‘đ?‘‘đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ?‘‘đ?‘‘đ?‘‘đ?‘‘

= đ??źđ??źđ?‘?đ?‘?đ?‘?đ?‘? − đ?‘‘đ?‘‘đ?‘–đ?‘–đ?‘Žđ?‘Ž +

đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘” đ??źđ??źđ?‘Žđ?‘Žđ?‘Žđ?‘Ž 2đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘?

Natural Reference Frame

đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?

1 ̇ = −đ??žđ??žđ?‘‘đ?‘‘ đ?‘’đ?‘’đ?‘‘đ?‘‘ + đ?‘…đ?‘…đ??źđ??źđ?‘‘đ?‘‘ + đ?‘‰đ?‘‰đ?‘”đ?‘”đ?‘”đ?‘” + đ??żđ??żđ??źđ??źđ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? 1 ̇ đ?‘‘đ?‘‘đ?‘žđ?‘žâ€˛ = −đ??žđ??žđ?‘žđ?‘ž đ?‘’đ?‘’đ?‘žđ?‘ž + đ?‘…đ?‘…đ??źđ??źđ?‘žđ?‘ž + đ??żđ??żđ??źđ??źđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘žđ?‘ž đ?‘‰đ?‘‰đ?‘?đ?‘?đ?‘?đ?‘? đ?‘‘đ?‘‘đ?‘‘đ?‘‘′

dq Reference Frame

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P. R. Rivera, M. L. McIntyre, M. Mohebbi, and J. Latham, “ Nonlinear Control for Single-Stage, SinglePhase Grid-Connected Photovoltaic Systems,� in Proc. of Control and Modelling for Power Electronics, COMPEL, July, 2017.

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Nonlinear Control for Single-Stage, Single-Phase‌.. Instantaneous Circuit Simulation

Fig. 11 đ??źđ??źđ?‘‘đ?‘‘ , đ??źđ??źđ?‘žđ?‘ž , and references current

Fig. 7 PV and Ideal Power

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Fig. 13 Grid voltage and current

P. R. Rivera, M. L. McIntyre, M. Mohebbi, and J. Latham, “ Nonlinear Control for Single-Stage, Single-Phase Grid-Connected Photovoltaic Systems,� in Proc. of Control and Modelling for Power Electronics, COMPEL, July, 2017.

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Current Control For Three-Phase Inverter in the Presence of Unknown Grid Parameters Control Objective Design đ??ˇđ??ˇđ?›žđ?›ž đ?‘Ąđ?‘Ą and đ??ˇđ??ˇđ?›żđ?›ż đ?‘Ąđ?‘Ą to force đ??źđ??źđ?›žđ?›ž đ?‘Ąđ?‘Ą and đ??źđ??źđ?›żđ?›ż đ?‘Ąđ?‘Ą to follow their respective reference currents đ??źđ??źđ?›žđ?›žâˆ— đ?‘Ąđ?‘Ą and đ??źđ??źđ?›żđ?›żâˆ— đ?‘Ąđ?‘Ą in the presence of the unknown grid parameters: đ?‘‰đ?‘‰đ?‘”đ?‘” , đ?œ”đ?œ” and đ?œƒđ?œƒ đ?‘Ąđ?‘Ą . An observer will also be developed for đ?œƒđ?œƒĚ‚ đ?‘Ąđ?‘Ą . It is to be noted that through the Lyapunov analysis we can prove the grid phase estimation angle đ?œƒđ?œƒďż˝ đ?‘Ąđ?‘Ą → 0 as đ?‘Ąđ?‘Ą → ∞, hence after convergence đ??źđ??źđ?›žđ?›žâˆ— đ?‘Ąđ?‘Ą = đ??źđ??źđ?‘‘đ?‘‘∗ đ?‘Ąđ?‘Ą and đ??źđ??źđ?›żđ?›żâˆ— đ?‘Ąđ?‘Ą = đ??źđ??źđ?‘žđ?‘žâˆ— đ?‘Ąđ?‘Ą . đ??żđ??ż

đ??źđ??źđ?›žđ?›žĚ‡ đ??ˇđ??ˇđ?›žđ?›ž = đ?‘‰đ?‘‰đ?‘‘đ?‘‘đ?‘‘đ?‘‘ − đ?‘…đ?‘… đ??ˇđ??ˇđ?›żđ?›ż �̇ đ??źđ??źđ?›żđ?›żĚ‡ đ?œƒđ?œƒđ??żđ??ż

1 đ??ˇđ??ˇđ?›žđ?›ž ≜ đ??ˇđ??ˇđ?›żđ?›ż đ?‘‰đ?‘‰đ?‘‘đ?‘‘đ?‘‘đ?‘‘

đ?‘…đ?‘… �̇ đ?œƒđ?œƒđ??żđ??ż đ?‘Ąđ?‘Ą

đ??źđ??źđ?›žđ?›ž �̇ ďż˝ −đ?œƒđ?œƒđ??żđ??ż − đ?‘‰đ?‘‰đ?‘”đ?‘” cos đ?œƒđ?œƒ đ??źđ??źđ?›żđ?›ż sin đ?œƒđ?œƒďż˝ đ?‘…đ?‘…

đ??źđ??źĚƒđ?›žđ?›ž đ??źđ??źđ?›žđ?›ž �̇ đ?‘‰đ?‘‰ďż˝ −đ?œƒđ?œƒđ??żđ??ż + đ?‘”đ?‘” + đ?‘˜đ?‘˜1 đ??źđ??źđ?›żđ?›ż đ??źđ??źĚƒđ?›żđ?›ż 0 đ?‘…đ?‘…

ďż˝ + đ?‘˜đ?‘˜1 + 1 đ??źđ??źĚƒđ?›żđ?›ż đ?œƒđ?œƒďż˝ ≜ đ??żđ??żđ??źđ??źĚƒđ?›żđ?›ż + ďż˝ đ?œ”đ?œ” đ?‘Ąđ?‘Ą0

27

đ?‘Ąđ?‘Ą

đ?œ”đ?œ” ďż˝ ≜ đ?‘˜đ?‘˜đ?œ”đ?œ” đ??żđ??żđ??źđ??źĚƒđ?›żđ?›ż + đ?‘˜đ?‘˜1 ďż˝ đ??źđ??źĚƒđ?›żđ?›ż đ?‘Ąđ?‘Ą0

đ?‘‰đ?‘‰ďż˝đ?‘”đ?‘”̇ ≜ đ?‘˜đ?‘˜đ?‘‰đ?‘‰ đ??źđ??źĚƒđ?›žđ?›ž

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Current Control For Three-Phase Inverter ‌‌ Instantaneous Circuit Simulation

Figure 2: Current Tracking for Trial 1

Figure 5: Current Tracking for Trial 2

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Figure 3: Grid Parameter Estimation for Trial 1

Figure 4: Control Signals in Both Frames for Trial 1

Figure 6: Grid Parameter Estimation for Trial 2

Figure 7: Control Signals in Both Frames for Trial 2

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Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Micro-Grid Application

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Control Objectives • Grid-Connected Inverter Systems with LC filter: 1. Simultaneously:  Inject clean current (Low THD) to the grid.  Regulate the output voltage to track a reference voltage. 2. Unity power factor at the grid side. 3. Ensure seamless transition between grid-connected and standalone modes.  Maintain consistent control system structure

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Backstepping Control for Grid-Connected SinglePhase Inverter Utilizing Variable Structure Observer Control Objective :to maintain low THD of the local load voltage đ?‘‰đ?‘‰đ?‘œđ?‘œ (đ?‘Ąđ?‘Ą) regardless of the type of load and achieve the reference output voltage đ?‘‰đ?‘‰đ?‘œđ?‘œ đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; đ?‘Ąđ?‘Ą , hence đ?‘‰đ?‘‰đ?‘œđ?‘œ đ?‘Ąđ?‘Ą → đ?‘‰đ?‘‰đ?‘œđ?‘œ đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; đ?‘Ąđ?‘Ą as đ?‘Ąđ?‘Ą → ∞. The stability analysis đ?‘Ąđ?‘Ą . Also, the current control objective is exchanging clean current with the will prove đ?‘‰đ?‘‰ďż˝đ?‘œđ?‘œ đ?‘Ąđ?‘Ą → đ?‘‰đ?‘‰đ?‘œđ?‘œ đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;

grid by regulating the grid current đ??źđ??ź2 đ?‘Ąđ?‘Ą to a reference current đ??źđ??ź2đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; đ?‘Ąđ?‘Ą , hence đ??źđ??ź2 đ?‘Ąđ?‘Ą → đ??źđ??ź2đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; đ?‘Ąđ?‘Ą as đ?‘Ąđ?‘Ą → ∞.

đ??żđ??żđ?‘“đ?‘“ đ??źđ??ź1̇ = đ?‘‰đ?‘‰đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ??ˇđ??ˇ + đ?‘‘đ?‘‘0 − đ?‘‰đ?‘‰đ?‘œđ?‘œ

đ??śđ??śđ?‘“đ?‘“ đ?‘‰đ?‘‰đ?‘œđ?‘œĚ‡ = đ??źđ??ź1 − đ??źđ??ź2 − đ??źđ??źđ?‘œđ?‘œ

đ??żđ??żđ?‘”đ?‘” đ??źđ??ź2̇ = đ?‘‰đ?‘‰đ?‘œđ?‘œ − đ?‘‰đ?‘‰đ?‘”đ?‘”

đ?‘‰đ?‘‰đ?‘œđ?‘œĚˆ =

1 đ?‘‰đ?‘‰ đ??ˇđ??ˇ + đ?‘‘đ?‘‘0 − đ?‘‰đ?‘‰đ?‘œđ?‘œ + đ??żđ??żđ?‘“đ?‘“ đ??śđ??śđ?‘“đ?‘“ đ?‘‘đ?‘‘đ?‘‘đ?‘‘ 1 1 (đ?‘‰đ?‘‰ đ?‘”đ?‘” − đ?‘‰đ?‘‰đ?‘œđ?‘œ ) − đ??źđ??źđ?‘œđ?‘œĚ‡ đ??żđ??żđ?‘”đ?‘” đ??śđ??śđ?‘“đ?‘“ đ??śđ??śđ?‘“đ?‘“

đ??ˇđ??ˇ ≜

32

đ??żđ??żđ?‘“đ?‘“ đ??śđ??śđ?‘“đ?‘“ đ??žđ??žđ?‘”đ?‘” 1 đ??źđ??ź2đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; + đ??žđ??žđ?‘”đ?‘” đ??źđ??ź2Ěˆ đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x;đ?‘&#x; − {đ??żđ??żđ?‘”đ?‘” ⃛ đ?‘‰đ?‘‰đ?‘”đ?‘” − đ?‘‰đ?‘‰đ?‘œđ?‘œ + đ?œ”đ?œ”đ?‘‰đ?‘‰đ?‘šđ?‘š đ?‘?đ?‘?đ?‘?đ?‘?đ?‘?đ?‘? đ?œƒđ?œƒ − đ?‘‰đ?‘‰ďż˝đ?‘œđ?‘œĚ‡ + đ?‘‘đ?‘‘Ě‚ − đ?œ”đ?œ”2 đ?‘‰đ?‘‰đ?‘šđ?‘š đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ + đ?‘‘đ?‘‘̂̇ đ?‘‰đ?‘‰đ?‘‘đ?‘‘đ?‘‘đ?‘‘ đ??żđ??żđ?‘”đ?‘” đ??żđ??żđ?‘”đ?‘” đ??śđ??śđ?‘“đ?‘“ 2 −đ??žđ??ž1đ?‘?đ?‘? đ?‘’đ?‘’ − (đ?‘˜đ?‘˜1 đ?‘˜đ?‘˜2 + 1)đ?‘‰đ?‘‰ďż˝đ?‘œđ?‘œ − đ?‘˜đ?‘˜3 đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ đ?‘ đ?‘‰đ?‘‰ďż˝đ?‘œđ?‘œ + đ??žđ??ž2đ?‘?đ?‘? đ?‘?đ?‘?ďż˝ + đ?‘’đ?‘’} − đ?‘‘đ?‘‘Ě‚ 0 đ?‘œđ?‘œ

đ?‘œđ?‘œ

0

Moath, Alqatamin, M. L. McIntyre, Joseph Latham, “Backstepping Control for Grid-Connected Single-Phase Inverter Utilizing Variable Structure Observer,� American Control Conference (ACC2019), Under Review.

10/15/2018

Backstepping Control for Grid-Connected SinglePhase Inverter Utilizing Variable Structure Observer

Tracking response of the output voltage for nonlinear local load.

33

Current tracking response during seamless transfer between SA and GC modes.

Output voltage response during seamless transfer between SA and GC modes.

Tracking response of the grid current under nonlinear local load.

System response to show unity power factor under nonlinear load.

Moath, Alqatamin, M. L. McIntyre, Joseph Latham, “Backstepping Control for Grid-Connected Single-Phase Inverter Utilizing Variable Structure Observer,� American Control Conference (ACC2019), Under Review.

10/15/2018

Other Relevant Works Control Systems for FACTS Devices • Moath, Alqatamin, M. L. McIntyre, “' 'Nonlinear Adaptive Control for Power System with Static VAR Compensator,” The 3rd IEEE Workshop on the Electronic Grid (EGRID2018), Charleston, SC, USA, to appear. • Moath, Alqatamin, M. L. McIntyre, Joseph Latham, P. Rivera, N. Hawkins “Nonlinear Adaptive Control Design for Power System with STATCOM Device,” American Control Conference (ACC2018), Milwaukie, Wisconsin, USA.

Active Power Buffering • Joseph Latham, M. L. McIntyre, “A Novel Controller for Power Decoupling in a Single-Phase Grid-Tied Inverter Using a Boost Converter,” The 44th Annual Conference of the IEEE Industrial Electronics Society (IECON2018), Washington DC, USA. 34

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Outline • • • • • • •

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Introduction Existing Control Schemes For Grid Connected Inverters Model Based Approach Applications Areas 3 φ and 1φ Grid Connected Inverter Control Solutions Micro-Grid Control Solutions Conclusions

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Conclusion • Grid connected inverter based systems are a critical component in the power system • Primary-Level control schemes assume linearity with little to no disturbances • Advanced control schemes can compensate for unmolded, nonlinearity, uncertainty, and disturbances • Move away from cascaded approaches • Creating a faster, more accurate controllable system • Benefit from Model-Based Approaches – Observers, Fault Detections, Identification, Abatement, others……

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