Low Cost Stand-alone Renewable Photovoltaic/Wind Energy Utilization Schemes by Liang Yang Supervisor: Dr. A. M. Sharaf

Presentation Outline Introduction Research Objectives Low Cost Stand-alone Renewable Photovoltaic/Wind Energy Utilization Schemes and Error Driven Controllers Conclusions and Recommendations for Future Research Publications Questions & Answers Presentation Outline

Introduction Photovoltaics (PV) PV cells PV modules PV arrays PV systems: batteries, battery charge controllers, maximum power point trackers (MPPT), solid state inverters, rectifiers (battery chargers), generators, structure

PV cell, PV module and PV array

The Advantages of PV Energy Clean and green energy source that has virtually no environmental polluting impact Highly reliable and needs minimal maintenance Costs little to build and operate Modular and flexible in terms of sizes, ratings and applications

Applications of PV Systems Stand-alone PV energy systems: Small village electricity supply Water pumping and irrigation systems Cathodic protection Communications Lighting and small appliances Emergency power systems and lighting systems Stand-alone hybrid renewable energy systems Electric utility systems

The circuit diagram of the solar cell PV Cell Model Current source: proportional to the light falling on the cell in parallel with a diode: Temperature dependence of the photo-generated current (I ph ). Temperature dependence of the reverse saturation current of the diode D 0 (I 0 ). Series resistance (R s ): gives a more accurate shape between the maximum power point and the open circuit voltage. Shunt diode D 0 with the diode quality factor set to achieve the best curve match.

Nonlinear I-V Characteristics of PV Cell

I-V characteristics of a typical PV array with various conditions

PV array equivalent circuit block model using the MATLAB/Simulink/SimPowerSystems software

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 operating power point. MPPT controller is a power electronic DC/DC chopper 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 power that is also necessary to maximize the photovoltaic energy utilization

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

The Performance of any Stand-alone PV System Depends on: PV System Depends on: Electric load operating conditions/excursions/ switching Ambient/junction temperature (T x ) Solar insolation/irradiation variations (S x )

Research Objectives 1. Develop/test/validate full mathematical models for PV array modules and a number of stand- alone renewable photovoltaic and hybrid photovoltaic/wind energy utilization schemes in MATLAB/Simulink/SimPowerSystems software environment.

Research Objectives (Continue) 2. Select parameters to validate a number of novel efficient low cost dynamic error driven maximum photovoltaic power tracking controllers developed by Dr. A.M. Sharaf for four novel low cost stand-alone renewable photovoltaic and hybrid photovoltaic/wind energy utilization schemes: Photovoltaic Four-Quadrant PWM converter PMDC motor drive scheme: PV-DC Scheme I. Photovoltaic DC/DC dual converter scheme: PV-DC Scheme II. Photovoltaic DC/AC six-pulse inverter scheme: PV-AC Scheme. Hybrid renewable photovoltaic/wind energy utilization scheme: Hybrid PV/Wind Scheme.

Low Cost Stand-alone Renewable Photovoltaic/Wind Energy Utilization Schemes and Error Driven Controllers Photovoltaic Four-Quadrant PWM converter PMDC motor drive scheme: PV-DC Scheme I. Photovoltaic DC/DC dual converter scheme: PV-DC Scheme II. Photovoltaic DC/AC six-pulse inverter scheme: PV-AC Scheme. Hybrid renewable photovoltaic/wind energy utilization scheme: Hybrid PV/Wind Scheme.

Photovoltaic Four-Quadrant PWM Converter PMDC Motor Drive Scheme: PV-DC Scheme I Photovoltaic powered Four-Quadrant PWM converter PMDC motor drive system (Developed by Dr. A.M. Sharaf)

Four-quadrant Operation of PWM Converter PMDC motor drive Quadrant 1: Forward motoring (buck or step-down converter mode) Q 1 –on Q 2 –chopping Q 3 –off Q 4 –off Current freewheeling through D 3 and Q 1 Quadrant 2: Forward regeneration (boost or step-up converter mode) Q 1 –off Q 2 –off Q 3 –off Q 4 –chopping Current freewheeling through D 1 and D 2 Quadrant 3: Reverse motoring (buck converter mode) Q 1 –off Q 2 –off Q 3 –on Q 4 –chopping Current freewheeling through D 1 and Q 3 Quadrant 4: Reverse regeneration (boost converter mode) Q 1 –off Q 2 –chopping Q 3 –off Q 4 – off Current freewheeling through D 3 and D 4

Variations of Ambient Temperature and Solar Irradiation Variation of ambient temperature (T x ) Variation of solar irradiation (S x )

Dynamic Error Driven Proportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. A.M. Sharaf)

Digital Simulation Results with PI Controller for Trapezoidal Reference Speed Trajectory

Digital Simulation Results with PI Controller for Trapezoidal Reference Speed Trajectory (Continue)

Digital Simulation Results with PI Controller for Sinusoidal Reference Speed Trajectory

Digital Simulation Results with PI Controller for Sinusoidal Reference Speed Trajectory (Continue)

Dynamic Error Driven Self Adjusting Controller (SAC) Dynamic tri-loop self adjusting control (SAC) system (Developed by Dr. Sharaf)

Digital Simulation Results with SAC for Trapezoidal Reference Speed Trajectory

Digital Simulation Results with SAC for Trapezoidal Reference Speed Trajectory (Continue)

Digital Simulation Results with SAC for Sinusoidal Reference Speed Trajectory

Digital Simulation Results with SAC for Sinusoidal Reference Speed Trajectory (Continue)

Photovoltaic DC/DC Dual Converter Scheme: PV-DC Scheme II Stand-alone photovoltaic DC/DC dual converter scheme for village electricity use

Dynamic Error Driven Proportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)

Digital Simulation Results with PI Controller Without controller With PI controller

Digital Simulation Results with PI Controller (Continue) Without controller With PI controller

Dynamic Error Driven Variable Structure Sliding Mode Controller (SMC) Dynamic dual-loop error driven variable structure Sliding Mode Control (SMC) system (Developed by Dr. A.M. Sharaf)

Switching surface in the (e t -ė t ) phase plane

Digital Simulation Results with SMC Without controller With SMC

Digital Simulation Results with SMC (Continue) Without controller With SMC

Photovoltaic DC/AC Six-pulse Inverter Scheme: PV-AC Scheme Stand-alone photovoltaic DC/AC six-pulse inverter scheme for village electricity use (Developed by Dr. A.M. Sharaf)

Variations of Ambient Temperature and Solar Irradiation Variation of ambient temperature (T x ) Variation of solar irradiation (S x )

Dynamic Error Driven Proportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)

Digital Simulation Results with PI Controller Without controller With PI controller

Digital Simulation Results with PI Controller (Continue) Without controller With PI controller

Dynamic Error Driven Variable Structure Sliding Mode Controller (SMC) Dynamic tri-loop error driven variable structure Sliding Mode Control (SMC) system (Developed by Dr. A.M. Sharaf)

Digital Simulation Results with SMC Without controller With SMC

Digital Simulation Results with SMC (Continue) Without controller With SMC

Hybrid Renewable Photovoltaic/Wind Energy Utilization Scheme: Hybrid PV/Wind Scheme Stand-alone hybrid photovoltaic/wind energy utilization scheme for village electricity use (Developed by Dr. A.M. Sharaf)

Variations of Wind Speed (Vw) Variation of wind speed (Vw)

Dynamic Error Driven Proportional plus Integral (PI) Controller Dynamic tri-loop error driven Proportional plus Integral control system (Developed by Dr. Sharaf)

Digital Simulation Results with PI Controller Without controller With PI controller

Digital Simulation Results with PI Controller (Continue) Without controller With PI controller

The loop weighting factors (γ v, γ i and γ p ) and control gains (K p, K i ) are assigned to minimize a selected time weighted excursion index J 0 (Developed by Dr. A.M. Sharaf) where is the magnitude of the hyper-plane error excursion vector N= T 0 /T sample T 0 : Largest mechanical time constant in the hybrid system (10s) T sample : Sampling time (0.2ms)

Time Weighted Excursion Index J 0 Digital simulation results of time weighted excursion index J 0 with different proportional and integral gains

Conclusions and Recommendations for Future Research (I) 1. The full mathematical models for PV array modules were fully developed including the inherently nonlinear I-V characteristics and variations under ambient temperature and solar irradiation conditions. 2. The proposed stand-alone renewable photovoltaic and hybrid photovoltaic/wind energy utilization schemes and robust dynamic control strategies were digitally simulated and validated using the MATLAB/Simulink/SimPowerSystems software environment. 3. The dynamic controllers require only the measured values of voltage and current signals in addition to the motor speed signals that can be easily measured with low cost sensors and transducers. 4. The proposed low cost stand-alone renewable photovoltaic and hybrid photovoltaic/wind energy utilization schemes are suitable for resort/village electricity application in the range of (1500 watts to watts), mostly for water pumping, ventilation, lighting, irrigation and village electricity use in arid remote communities.

Proposed Schemes, Controllers and Applications

Conclusions and Recommendations for Future Research (II) 1. It is necessary to validate the proposed novel dynamic maximum photovoltaic power tracking control strategies by a specific laboratory facility using the low cost micro controllers. 2. The proposed dynamic effective and robust error driven control strategies can be extended to other control system applications. They are also flexible by adding supplementary control loops to adapt any control objectives of any systems. Further work can be focused on Artificial Intelligence (AI) control strategies. 3. The research can be expanded to the design and validation of dynamic FACTS with stabilization and compensation control strategies for other stand-alone renewable energy resource schemes as well as grid-connected renewable energy systems to make maximum utilization of the available energy resources.

Publications [1] 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 , 2005 (Accepted). [2] 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, Canada, May 1-4, 2005 (Accepted). [3] 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). [4] A.M. Sharaf, Liang Yang, "An Efficient Photovoltaic DC Village Electricity Scheme Using a Sliding Mode Controller," 2005 IEEE Conference on Control Applications (CCA05), Toronto, Canada, August 28-31, 2005 (Submitted). [5] A.M. Sharaf, Liang Yang, "A Novel Efficient Stand-alone Photovoltaic Energy Utilization Scheme for Village Electricity," 8th International Conference on Electrical Power Quality and Utilization, Cracow, Poland, September 21-23, 2005 (Submitted). [6] A.M. Sharaf, Liang Yang, "A Novel Efficient Stand-alone Hybrid Photovoltaic/Wind Energy Utilization Scheme for Village Electricity," International Conference on Electrical Drives and Power Electronics, Dubrovnik, Croatia, September 26-28, 2005 (Submitted). [7] A.M. Sharaf, Liang Yang, "Novel Dynamic Control Strategies for Efficient Utilization of a Stand-alone Photovoltaic System," Electric Power Systems Research (Submitted).