Solar panel model with MPPT in Simulink - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the solar panel's open-circuit voltage variable.

Simulink

Voc = [1];  % Open-circuit voltage in volts

Drag options to blanks, or click blank then click option'

A21.0

B5.0

C15.0

D30.0

Attempts:

3 left

💡 Hint

Common Mistakes

Using a current value instead of voltage.

Choosing a voltage too low for open-circuit condition.

The open-circuit voltage (Voc) is typically around 21 volts for this solar panel model.

2fill in blank

medium

Complete the code to calculate the solar panel current using the diode equation.

Simulink

Iph = [1];  % Photocurrent in amperes
I = Iph - I0 * (exp((V + I*Rs) / (nVt)) - 1) - (V + I*Rs) / Rsh;

Drag options to blanks, or click blank then click option'

A0.5

B5.0

C3.5

D10.0

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing photocurrent with saturation current.

Using a value too high for typical solar panels.

The photocurrent (Iph) is the current generated by sunlight, here 3.5 A is typical under standard test conditions.

3fill in blank

hard

Fix the error in the MPPT algorithm update step.

Simulink

dV = V - V_prev;
dP = P - P_prev;
if dP [1] 0:
    if dV > 0:
        V_ref = V_ref + deltaV;
    else:
        V_ref = V_ref - deltaV;

Drag options to blanks, or click blank then click option'

A==

B<=

C>=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using equality or less than instead of greater than.

Not comparing dP correctly causing wrong voltage updates.

The MPPT algorithm adjusts voltage reference only if power change (dP) is positive, so the condition should be dP > 0.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps voltage to power for voltages above 10V.

Simulink

power_map = {V: V[1]I for V, I in measurements.items() if V [2] 10}

Drag options to blanks, or click blank then click option'

A*

B+

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of multiplication for power.

Filtering voltages less than 10 instead of greater.

The power is voltage times current (V * I), and we filter voltages greater than 10 volts.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that stores power for voltages above 15V and currents below 5A.

Simulink

filtered_power = {V[1]I: I[2]V for V, I in data.items() if V [3] 15 and I < 5}

Drag options to blanks, or click blank then click option'

A*

B+

C>

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication instead of subtraction or addition.

Incorrect voltage filtering condition.

The dictionary keys are voltage minus current (V - I), values are current plus voltage (I + V), filtered for voltage > 15 and current < 5.

Practice

1. What is the main purpose of the MPPT (Maximum Power Point Tracking) in a solar panel model in Simulink?

easy

A. To find the voltage and current that produce the maximum power output

B. To store energy in batteries

C. To convert DC to AC power

D. To measure sunlight intensity

Solution

1. Step 1: Understand MPPT function

   MPPT is designed to find the best operating point where the solar panel produces maximum power.

2. Step 2: Identify MPPT role in Simulink model

   In Simulink, MPPT adjusts voltage and current to maximize power output from the solar panel.

3. Final Answer:

   To find the voltage and current that produce the maximum power output -> Option A

4. Quick Check:

   MPPT = Max power point finder [OK]

Hint: MPPT always finds max power point, not storage or conversion [OK]

Common Mistakes:

• Confusing MPPT with battery storage
• Thinking MPPT converts power types
• Assuming MPPT measures sunlight only

2. Which Simulink block is typically used to represent the solar panel in a solar panel model with MPPT?

easy

A. Scope block

B. Battery block

C. DC-DC Converter block

D. PV Array block

Solution

1. Step 1: Identify solar panel representation

   The PV Array block models the photovoltaic solar panel's electrical behavior in Simulink.

2. Step 2: Differentiate other blocks

   Battery stores energy, DC-DC Converter changes voltage, Scope displays signals, so they are not solar panels.

3. Final Answer:

   PV Array block -> Option D

4. Quick Check:

   Solar panel = PV Array block [OK]

Hint: Solar panel block is called PV Array in Simulink [OK]

Common Mistakes:

• Choosing Battery block instead of PV Array
• Confusing Scope block as a model block
• Selecting DC-DC Converter as solar panel

3. Given this Simulink model snippet for MPPT control:

V = 30; I = 5;
P = V * I;
if P > P_prev
  V_ref = V + 0.1;
else
  V_ref = V - 0.1;
end
P_prev = P;

What is the value of V_ref after running this code if P_prev was 140 before execution?

medium

A. 140

B. 29.9

C. 30.1

D. 30

Solution

1. Step 1: Calculate current power P

   P = V * I = 30 * 5 = 150.

2. Step 2: Compare P with P_prev and update V_ref

   Since 150 > 140, V_ref = V + 0.1 = 30 + 0.1 = 30.1.

3. Final Answer:

   30.1 -> Option C

4. Quick Check:

   150 > 140 so V_ref = 30 + 0.1 = 30.1 [OK]

Hint: Calculate power first, then compare to update voltage [OK]

Common Mistakes:

• Using old V instead of updated V_ref
• Mixing up greater than and less than conditions
• Forgetting to update P_prev

4. In a Simulink MPPT model, the output power does not increase as expected. Which of the following is a likely error in the MPPT algorithm block?

medium

A. The voltage reference is not updated based on power comparison

B. The solar panel block is missing

C. The Scope block is not connected

D. The battery capacity is too low

Solution

1. Step 1: Analyze MPPT algorithm role

   MPPT must update voltage reference to track max power point.

2. Step 2: Identify impact of no voltage update

   If voltage reference stays constant, power won't increase even if sunlight changes.

3. Final Answer:

   The voltage reference is not updated based on power comparison -> Option A

4. Quick Check:

   MPPT voltage update missing = no power increase [OK]

Hint: MPPT must update voltage ref to increase power [OK]

Common Mistakes:

• Blaming missing Scope for power issues
• Confusing battery capacity with MPPT function
• Ignoring voltage reference updates

5. You want to improve the MPPT algorithm in your Simulink solar panel model to handle rapidly changing sunlight conditions. Which approach is best to implement?

hard

A. Remove the MPPT block and rely on battery charging only

B. Use a perturb and observe method with adaptive step size

C. Fix the voltage reference to a constant value

D. Increase the solar panel size without changing MPPT

Solution

1. Step 1: Understand rapid sunlight changes impact

   Rapid changes require MPPT to quickly adjust voltage to track max power.

2. Step 2: Evaluate methods to improve MPPT

   Adaptive step size in perturb and observe method allows faster and stable tracking.

3. Step 3: Eliminate unsuitable options

   Fixing voltage or removing MPPT ignores changes; increasing panel size doesn't improve tracking.

4. Final Answer:

   Use a perturb and observe method with adaptive step size -> Option B

5. Quick Check:

   Adaptive MPPT handles rapid changes best [OK]

Hint: Adaptive step size in MPPT improves tracking speed [OK]

Common Mistakes:

• Keeping voltage fixed despite sunlight changes
• Removing MPPT thinking battery alone suffices
• Increasing panel size without MPPT tuning