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Low Cost Stand-alone Renewable Photovoltaic/Wind Energy Utilization Schemes. Liang Yang Supervisor: Dr. A. M. Sharaf. Presentation Outline. Presentation Outline. Introduction Research Objectives Low Cost Stand-alone Photovoltaic/Wind Schemes and Error Driven Controllers
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Low Cost Stand-alone RenewablePhotovoltaic/Wind Energy Utilization Schemes Liang Yang Supervisor: Dr. A. M. Sharaf
Presentation Outline Presentation Outline • Introduction • Research Objectives • Low Cost Stand-alone Photovoltaic/Wind Schemes and Error Driven Controllers • Preliminary Results • Time Line • Publications
Introduction • PV cells • PV modules • PV arrays • PV systems • Stand-alone photovoltaic systems • Hybrid renewable energy systems
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 • Almost has no environmental polluting impact • Modular and flexible in terms of size, ratings and applications
Economical uses of stand-alone PV systems: • Small village electricity supply • Water pumping and irrigation systems • Cathodic protection • Communications • Lighting and small appliances • Emergency power systems and lighting systems
I-V characteristics of the single solar cell The circuit diagram of the single solar cell
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 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
I-V and P-V characteristics of a typical PV array at a fixed ambient temperature and solar irradiation condition
I-V characteristics of a typical PV array with various conditions
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)
Research Objectives • Develop/test/validate mathematical models for stand-alone photovoltaic PV and PV/wind energy conversion schemes in MATLAB/Simulink/SimPowerSystems software environment. • Design/test/validate novel maximum photovoltaic power tracking controllers for photovoltaic PV and PV/wind energy conversion schemes namely: (1) Photovoltaic Four-Quadrant PWM converter PMDC motor drive: PV-DC scheme I. (2) Photovoltaic DC/DC dual converter: PV-DC scheme II. (3) Photovoltaic DC/AC inverter: PV-AC scheme. (4) Hybrid photovoltaic/wind energy utilization scheme.
Low Cost Stand-alone Photovoltaic/Wind Schemesand Error Driven Controllers • Photovoltaic Four-Quadrant PWM Converter PMDC Motor Drive: PV-DC Scheme I • Photovoltaic DC/DC Dual Converter:PV-DC Scheme II • Photovoltaic DC/AC Inverter: PV-AC Scheme • Hybrid Photovoltaic/Wind Energy Utilization Scheme
Photovoltaic Four-Quadrant PWM Converter PMDC Motor Drive: PV-DC Scheme I Photovoltaic powered Four-Quadrant PWM converter PMDC motor drive system
Dynamic Error DrivenProportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)
The loop weighting factors (γw, γi and γp) and gains (Kp, Ki) are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • is the total excursion error • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms)
Dynamic Error DrivenSelf Adjusting Controller (SAC) Dynamic tri-loop self adjusting control (SAC) system (Developed by Dr. Sharaf)
The loop weighting factors (γw, γI and γp) and the parameters k0 and β are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms) • t(k)=k·Tsample: Time at step k in seconds
Photovoltaic DC/DC Dual Converter:PV-DC Scheme II Stand-alone photovoltaic DC/DC dual converter scheme for village electricity use
Dynamic Error DrivenProportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)
The loop weighting factors (γw, γi and γv) and gains (Kp, Ki) are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • is the total excursion error • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms)
Dynamic Sliding Mode Controller (SMC) Dynamic error driven sliding mode control system (Developed by Dr. Sharaf)
The loop weighting factors (γw and γp) and the parameters C0 and C1 are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms)
Photovoltaic DC/AC Inverter: PV-AC Scheme Stand-alone photovoltaic DC/AC inverter scheme for village electricity use
Dynamic Error DrivenProportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)
The loop weighting factors (γv, γi and γp) and gains (Kp, Ki) are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • is the total excursion error • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms)
Hybrid Photovoltaic/Wind EnergyUtilization Scheme Stand-alone hybrid photovoltaic/wind energy utilization scheme
Dynamic Error DrivenProportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)
The loop weighting factors (γv, γi and γp) and gains (Kp, Ki) are assigned to minimize the time-weighted excursion index J0 (Developed by Dr. Sharaf) where • is the total excursion error • N= T0/Tsample • T0: Largest mechanical time constant (10s) • Tsample: Sampling time (0.2ms)
Preliminary Results Photovoltaic powered Four-Quadrant PWM converter PMDC motor drive system model using the MATLAB/Simulink/SimPowerSystems software
Variation of ambient temperature (Tx) Variation of solar irradiation (Sx) Test Variations of ambient temperature and solar irradiation
Ig vs. time Pg vs. time Vg vs. time Vg vs. Ig For trapezoidal reference speed trajectory
Pg vs. Ig & Vg ωref & ωm vs. time Iam vs. time ωm vs. Te For trapezoidal reference speed trajectory(Continue)
Ig vs. time Pg vs. time Vg vs. time Vg vs. Ig For sinusoidal reference speed trajectory
Pg vs. Ig & Vg ωref & ωm vs. time Iam vs. time ωm vs. Te For sinusoidal reference speed trajectory(Continue)
The digital simulation results validate the tri-loop dynamic error driven PI controller, ensures: • Good reference speed trajectory tracking with a small overshoot/undershoot and minimum steady state error • The motor inrush current Iam is kept to a specified limited value • Maximum PV solar power/energy tracking near knee point operation can be also achieved
Publications 1. A.M. Sharaf, Liang Yang, “A Novel Low Cost Stand-alone Photovoltaic Scheme for Four Quadrant PMDC Motor Drive,” International Conference on Renewable Energy and Power Quality (ICREPQ'05), Zaragoza, Spain, March 16-18, 2005. (Submitted) 2. A.M. Sharaf, Liang Yang, “A Novel Tracking Controller for a Stand-alone Photovoltaic Scheme,” International Conference on Communication, Computer and Power (ICCCP'05), Muscat, Sultanate of Oman, Feb. 14-16, 2005. (Accepted) 3. A.M. Sharaf, Liang Yang, “A Novel Maximum Power Tracking Controller for a Stand-alone Photovoltaic DC Motor Drive,” 18th Annual Canadian Conference on Electrical and Computer Engineering (CCECE05), Saskatoon, Saskatchewan, Canada, May 1-4, 2005. (Submitted)