PVMD Delft University of Technology Learning objective 1. Maximum - PowerPoint PPT Presentation

Incremental Conductance Technique Ravi Vasudevan PVMD Delft University of Technology

Learning objective 1. Maximum Power Point Tracking 1. Introduction to MPPT 2. Indirect Methods 3. Perturb and Observe 4. Incremental Conductance 5. Cost and Overview 2. Cables 3. Batteries 1. Introduction to Batteries 2. Characteristics of Batteries 3. Charge Controller

How to Power-Point Track I P P MPP Current [A] Power [W] I SC I MPP MPP Voltage [V] V MPP V OC V

MPPT Techniques Indirect MPP Tracking Direct

MPPT Techniques MPP Tracking Direct

Looking at the I-V/P-V Curve I P P MPP Current [A] Power [W] I SC I MPP MPP Voltage [V] V MPP V OC V

Looking at the I-V/P-V Curve I P P MPP Current [A] Power [W] I SC I MPP MPP Voltage [V] V MPP V OC V

Looking at the I-V/P-V Curve I P P MPP Current [A] Power [W] I SC I MPP MPP Voltage [V] V MPP V OC V

Looking at the I-V/P-V Curve I P dP = P MPP 0 dV Current [A] Power [W] I SC I MPP MPP Voltage [V] V MPP V OC V

Looking at the I-V/P-V Curve I P dP = P MPP 0 dV Current [A] Power [W] I SC I MPP MPP dP > 0 dV Voltage [V] V MPP V OC V

Looking at the I-V/P-V Curve I P dP = P MPP 0 dV dP Current [A] < 0 Power [W] dV I SC I MPP MPP dP > 0 dV Voltage [V] V MPP V OC V

Conductance relates to dP/dV Conductance G = I / V

Conductance relates to dP/dV Conductance G = I / V dP d ( IV ) dI = = + I V dV dV dV

Conductance relates to dP/dV Conductance G = I / V dP d ( IV ) dI = = + I V dV dV dV D dI I If sampling steps are small enough: » Incremental G D dV V

Conductance relates to dP/dV Conductance G = I / V dP d ( IV ) dI = = + I V dV dV dV D dI I If sampling steps are small enough: » Incremental G D dV V D dP I » + I V D dV V Incremental Conductance

Conductance relates to dP/dV Conductance G = I / V dP d ( IV ) dI = = + I V dV dV dV D dI I If sampling steps are small enough: » Incremental G D dV V D dP I I » + - = I V I V V 0 D dV V Incremental Conductance VS Conductance

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Comparing G to Incremental Conductance If

Incremental vs Instant Conductance I P dP = P MPP 0 dV dP Current [A] < 0 Power [W] dV I SC I MPP MPP dP > 0 dV Voltage [V] V MPP V OC V

Incremental vs Instant Conductance D I P I I = - P MPP D V V D I I Current [A] < - Power [W] D V V I SC I MPP MPP D I I > - D V V Voltage [V] V MPP V OC V

Block Diagram ΔI PV / ΔV PV = -I PV / V PV (at MPP) • ΔI PV / ΔV PV > -I PV / V PV (left of the MPP) • ΔI PV / ΔV PV < -I PV / V PV (right of the MPP) • IC Algorithm V PV (n-1,n) IF > V PN (n+1)>V PN (n) V PV (n+1) D IF = V PN (n+1)=V PN (n) I I ? - D I PV (n-1,n) V V IF < V PN (n+1)<V PN (n)

Conceptual Flowchart Start ΔV = 0? ΔI/ΔV = -I/V? ΔI = 0? ΔI/ΔV > -I/V? ΔI > 0? Increase Decrease Increase Decrease Voltage Voltage Voltage Voltage Return http://www.ni.com/white-paper/8106/en/