Let us say that we want to design a digital controller
for a DC-DC power converter that regulates the voltage to light
the LEDs in a car headlamp.
We use the SEPIC topology, where SEPIC
stands for single-ended primary inductor converter.
This is essentially a bus converter,
followed by a bulk boost converter,
and can increase or decrease source voltage as needed.
SEPIC converters typically require very high frequencies
in the range of hundreds of kilohertz.
We'll use rapid control prototyping,
as we want to develop and test our control
algorithm as fast as possible.
We also want to adapt the control, tune the parameters,
and measure data on the fly, from Simulink.
By using Simulink real-time and Speedgoat hardware,
we'll aim at automatically generating C or HDL code,
and configure all inputs and outputs from Simulink,
with Speedgoat driver blocks.
For rapid control prototyping, we'll
use a baseline real-time target machine, with an IO397
Simulink-programmable FPGA I/O module from Speedgoat,
as a Xilinx FPGA analog input and output channels,
as well as configurable digital I/O lines.
In this case, we will be using the analog inputs and the PWM
functionality to generate 100 kilohertz switching frequency.
With this flexible platform, we can also
use a PID Autotuner tuner blocks, from Simulink Control
Design, for automated tuning.
And by the way, if our DC-DC converter was not ready,
we could also use the switches in the power module
from Speedgoat.
And by the way, if our DC-DC converter was not ready,
we could also emulate the converter dynamics
using HEV develop of testing.
To develop a controller for a grid tied three-phase inverter,
we'll start with desktop simulation,
including the solar panel, the inverter, and the grid.
Once we're happy with the desktop simulation,
we generate C and HDL code automatically from Simulink.
We can then test our controller for the greater inverter
by connecting it to a Speedgoat target computer.
In this case, we'll use a Cinergia two-level, three-phase
inverter with an LCL filter for prototyping the power
electronics part.
Developing a grid tied inverter is a complex task, that
not only involves expensive hardware,
it also could affect the grid and other of its users.
We can reset the development process
with model-based design.
We would start with desktop simulation,
involving the plant and the controller.
Then, rapid control prototyping provides a reliable test
platform with proven I/O connectivity,
and the capacity to measure and change parameters on the fly.
Once the embedded controller seems ready,
it is still important to use hardware-in-the-loop testing
to validate and thoroughly test under all operating conditions
and full conditions.
It is just then that we deploy using production code
generation to an embedded platform.
We can learn more about this topic in a MATLAB expert talk
on grid tied solar inverters.
For doing rapid control prototyping
for a grid tied inverter, we could
use a performance real-time target
machine, including a large amount
of low-latency analog measurements.
In this case, we use Speedgoat analog I/O
modules with DMA memory access to achieve the lowest latency
with multiple measurements.
We also use a configurable FPGA I/O
module, including several FPGA gold
modules, like PWM generators.
We also have interrupts that are used
to create a link between the PWM and the analog
signals to make sure that we always measure currents
when the transistor in series is properly closed.
A measurement would not be valid otherwise.
Speedgoat interface from the Cinergia power converter
includes connectors for Speedgoat cables
to transfer both analog measurements from current
and voltage, and also to provide access to the gate drivers
via PWM switching, or similar.
The power converter interface also
includes electrical protection features,
like overcurrent protection, that provides
an additional safety mechanism.
For this sample, we used a 15 kilowatt two-level,
three-phase power converter from Cinergia.
But as Diego previously mentioned,
they are compatible interfaces for projects
requiring from a few hundred watts to around 160 kilowatts.