# Open loop Boost converter modeling in Simulink

Ming Sun / November 28, 2022

7 min read • ––– views

## Block diagram

The Boost converter power stage block diagram is shown in **Fig. 1**.

^{[1]}

## Equations

In order to create the model in Matlab, we have to derive equations first. For a Boost converter inductor, we have the following:

Where,

**Eq. 1** can be simplified as:

Where,

**Eq. 4** can be rewritten as:

For the output capacitor, we have the following:

**Eq. 6** can be rewritten as:

## Simulink modeling

The overall process to model the open loop Boost converter is similar as the open loop Buck converter modeling as described in **Ref. [2]**.

- First, let us import to
`integrator`

into the simulink cavans as shown in**Fig. 2**.

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- To mimic the switching behavior on the
`VSW`

net, we will use a`switch`

.**Fig. 2**shows the connections. Basically, when duty cycle`D`

is greater than`0.1`

,`VSW`

is connected to ground and while`D`

is less than`0.1`

,`VSW`

is connected to`Vout`

. This is exactly the switching behavior for a Boost converter.

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The setting of the pulse generator is as shown in **Fig. 4**.

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Since the overall process to build this Boost converter open loop model is similar of the process for the Buck converter, please refer to **Ref. [2]** if you are not familiar with the process. The completed open loop Boost converter model in Simulink is as shown in **Fig. 5**.

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## Simulation results

We know for a given Boost converter with `5Vin`

and `20%`

duty cycle, its output can be calculated as:

The simulation results from simulink are as shown in **Fig. 6**.

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**Fig. 7** shows the zoom-in waveforms. We can see that the `Vout`

average voltage meets our expectation.

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## References and materials

[1] Fundamentals of power electronics - Chapter 2

[2] Simulation of open-loop Buck converter in Simulink