Building a Simple Voltage Source Inverter
1 Introduction
In this tutorial you will build a simple three-phase voltage source inverter (VSI) for deployment on
the RT Box. The tutorial is oriented towards users making their first practical models for the RT Box
using PLECS Standalone and identifies potential missteps ones may make along the way.
The primary learning goal for the tutorial is to demonstrate the limitations of conventional switch
models in real-time applications, motivating the use of sub-cycle averaging and specialized hybrid
power modules in later tutorial exercises.
Before you begin
If this is your first time using the RT Box, you should complete the “Introduction
to the RT Box using PLECS” tutorial prior to starting this tutorial to understand how to build and de-
ploy basic models.
The tutorial is designed so that it can be completed with only an RT Box and a loopback cable. The
loopback cables are used to drive the RT Box analog and digital inputs from the RT Box outputs. A
D-SUB 37-pin male-to-female cable can be used for this purpose.
2 Building a VSI model in PLECS
In this section you will create a simple VSI model using the PLECS power modules and an open-loop
PWM generator. You will then run the plant and modulator on one RT Box. Note at this point that
running both plant and modulator together is not the normal approach for rapid control prototyping
(RCP) or hardware-in-the-loop (HIL) simulations. In these cases the controller or the plant is deployed
separately onto one RT Box and tested with the actual hardware or a controller in use. However, using
just one RT Box for both still allows users with only one RT Box to see important effects like sampling
resolution and execution time.
Sine Wave
Frequency: 50
Phase: [0 -1 1]/3
Units: Hertz, p.u.
PWM Out1
channel: 0 2
polar: 1
PWM
Out
PWM Out2
channel: 3 5
polar: 0
PWM
Out
L1
L: 0.001
R1
R: 1
A
Am1
L2
L: 0.001
R2
R: 1
A
Am2
L3
L: 0.001
R3
R: 1
A
Am3
V_dc
V: 800
Current
PWM
HB1
HB2
HB3
PWM Capture1
channel: 0 5
Ts: 2e-6
PWM
Capture
Figure 1: A simple real-time VSI model
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