A NOVEL EFFICIENT STANDALONE PHOTOVOLTAIC DC VILLAGE ELECTRICITY SCHEME

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A NOVEL EFFICIENT STAND-ALONE PHOTOVOLTAICDC
VILLAGE ELECTRICITY SCHEME

• A.M. Sharaf, SM IEEE, and Liang Yang
• Department of Electrical and Computer Engineering
• University of New Brunswick

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PRESENTATION OUTLINE

• Introduction
• System Model Description
• Novel Dynamic Error Driven PI Controller
• Digital Simulation Results
• Conclusions
• Future Work

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Introduction

• The advantages of PV solar energy
• Clean and green energy source that can reduce
  green house gases
• Highly reliable and needs minimal maintenance
• Costs little to build and operate (2-3/Wpeak)
• Almost has no environmental polluting impact
• Modular and flexible in terms of size, ratings
  and applications

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Maximum Power Point Tracking (MPPT)

• The photovoltaic system displays an inherently
  nonlinear current-voltage (I-V) relationship,
  requiring an online search and identification of
  the optimal maximum power operating point.
• MPPT controller/interface is a power electronic
  DC/DC converter or DC/AC inverter system inserted
  between the PV array and its electric load to
  achieve the optimum characteristic matching
• PV array is able to deliver maximum available
  solar power that is also necessary to maximize
  the photovoltaic energy utilization in
  stand-alone energy utilization systems (water
  pumping, ventilation)

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• I-V and P-V characteristics of a typical PV array
  at a fixed
• ambient temperature and solar irradiation
  condition

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• The performance of any stand-alone
• PV system depends on
• Electric load operating conditions/Excursions/
  Switching
• Ambient/junction temperature (Tx)
• Solar insolation/irradiation variations (Sx)

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System Model Description

• Key components
• PV array module model
• Power conditioning filter
• ? Blocking Diode
• ? Input filter (Rf1 Lf1)
• ? Storage Capacitor (C1)
• ? Output filter (Rf2 Lf2 and C2)
• SPWM controlled MOSFET or IGBT DC/DC
• dual converter (chopper)
• Loads

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• Stand-alone photovoltaic DC/DC chopper scheme for
  village electricity use

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Novel Dynamic Error DrivenPI Controller

• Three regulating loops
• The motor speed trajectory tracking loop
• The The first supplementary photovoltaic current
  tracking loop
• The second supplementary photovoltaic reference
  voltage tracking loop

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Dynamic tri-loop error driven Proportional plus
Integral control system
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• The global error signal (et) comprises
• 3-dimensional excursion vectors (ew, ei, ev)

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• The loop weighting factors (?w, ?i and ?v)
• are assigned to minimize the time-weighted
  excursion index J0
• where
• Re(k) Magnitude of the hyper-plane error
  excursion vector
• N T0/Tsample
• T0 Largest mechanical time constant (10s)
• Tsample Sampling time (0.2ms)

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Digital Simulation Results

• Stand-alone photovoltaic scheme model using the
  MATLAB/Simulink/SimPowerSystems software

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Test Variations of ambient temperature and solar
irradiation

• Variation of
• ambient temperature (Tx)

• Variation of
• solar irradiation (Sx)

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Without / with dynamic controller

• Ig vs. time
• Vg vs. time

• Ig vs. time
• Vg vs. time

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Without / with dynamic controller

• Pg vs. Time
• the increase of

• Pg vs. time
• PV power

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• The digital simulation results validate
• the tri-loop dynamic error driven
• PI Controller, ensures
• Good speed trajectory tracking with
• a small overshoot/undershoot and minimum
• steady state error
• Good photovoltaic current tracking
• Good photovoltaic reference voltage tracking
• Maximum PV solar power/energy tracking near
• knee point operation can be also achieved

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Conclusions

• The proposed dynamic error driven controller
  requires only the PV array output voltage and
  current signals and the DC motor speed signals
  that can be easily measured.
• The low cost stand-alone photovoltaic renewable
  energy scheme is suitable for village electricity
  application in the range of (150 watts to 15000
  watts), mostly for water pumping and irrigation
  use in arid developing countries.

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Future Work

• Other PV-DC, PV-AC and Hybrid
• PV/Wind energy utilization schemes
• New control strategies

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Future Work (Continue)Novel Dynamic Error
DrivenSliding Mode Controller (SMC)

• Three regulating loops
• The motor speed trajectory tracking loop
• The dynamic photovoltaic power tracking loop

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Dynamic dual-loop error-driven Sliding Mode
Control (SMC) system
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• The loop weighting factors (?w and?p) and the
  parameters C0 and C1 are assigned to minimize the
  time-weighted excursion index J0
• where
• N T0/Tsample
• T0 Largest mechanical time constant (10s)
• Tsample Sampling time (0.2ms)

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• Thank You!
• Questions?