In mid-2010s I’ve spent weeks on comparing different topologies for inverters and DC/DC-converters for PV-applications. One of these topologies was quite interesting as it had a surprise when calculating the equations for the duty cycle. Under specific circumstances this duty cycle went from a positive real value into a complex imaginary value. To understand why…
In 2023, I published a video on my YouTube channel about reading and processing the Behringer UltraNet protocol (see YouTube: Hacking Behringer’s Ultranet for an FPGA-based DIY audio mixer). in this blog post I’d like to take a bit more time to describe the background and the connection between the UltraNet device, FPGA, and the…
During my time as a scientific researcher at the University of Kassel, I worked on a couple of very different types of laboratory test-devices to check if a theoretical idea is working or not. Most of the time we designed not a very fancy and good looking device, but a functional PCB with the main-components…
This file calculates a theta-angle-signal based on the given frequency-information:
FPGAs are very useful when calculating plus or minus or dealing with large logic-vectors. Even multiplication is fine. But when it comes to dividing signals, FPGAs need support. Lothar Miller has a nice implemenation of a Radix-2-procedure to calculate the division of two fixed-point-numbers:
To convert a 6-phase signal into a 90° system, the following logic can be helpful:
I had a special BLDC motor with 6 phases. To control the motor with a field-orientet control (FOC) I had to implement a 6-phase conversion from a 90° alpha/beta system into a 6-phase system. This is the logic for this:
To convert a 90° system (alpha/beta) into a dq-system, the Park-Transformation is performed. The following logic can be used for Q15.16 fixed-point-signals:
For both microcontrollers and FPGAs its quite challenging to calculate sine- and cosine-values with good enough precision to calculate different things with higher accuracy. Mitu Raj and Roshan Raju implemented a nice Mini-Cordic-IP-Core that does exactly this: calculate sin/cos as fixed-point values that can be used within an FPGA.
The following logic performs an inverse park transformation and converts dq-components into alpha-beta-components. It uses the cordic implementation of Mitu Raj that supports angles between -360° and 360°. The implementation can be found in another snippet on this website.
