This past week, I finished the schematics for spookpower and spooktroller (the two components of the UPMC, Electric Boogaloo), and also finished a first pass of layout and routing. It was a lot of work. The silks are not final. These should be ready to order in the next few days. The power board has had a good amount of thought put into making it robust, with trace ampacity calculations and snubber circuits and all that put in, however the…
This week I worked with Bolaji on getting the motor to spin in both directions after getting the flux observer working. The flux observer functionality is the result of getting the ADCs working, and allows us to spin the motor faster and with higher torque than we have before. While the motor does spin in both directions, it produces more torque and is quieter in one direction. Investigating the code did not result in finding anything that would cause the…
This week, we got motor rotor estimator to actually commutate the motor. We are using a flux linkage observer to estimate rotor position, which involves measuring the ratio of magnetic flux applied to each of the three phases of the motor. We then apply a Clarke transform to translate into a 2-axis reference frame such that we can use the angle between the two to get the rotor electric angle. We also spent a while tuning the values of the…
This week, I worked on the battery management board schematics by reviewing the ASIC and picking out some components to regulate a 48v 15-cell series 18650 lithium ion battery pack that we are planning on using to power the UPMC. In addition to being able to sense the temperature, voltage, and current from every one of the cells, this board also needs to communicate with the Logic Board of the Electric Boogaloo. This means I have to look into connecting…
This week, I got the estimator working to actually commutate the motor and started the process of tuning it. I also have 90% finished the schematics for electric boogaloo and the routing will start after my next midterm. The way that we are sensing the rotor position uses a flux linkage observer, which essentially measures the ratio of the magnetic flux applied to each phase (integral of voltage over time) and compares it to the actual flux moving through the…
This week we finally got ADC triggering working properly. We managed to do this with a combination of timer synchronization and modifying the manufacturer timer driver function used for initialization. Because we are using center-aligned PWM as discussed in previous status reports, the timer’s counter counts from 0 to 1023 and back down to 0. Every time it reaches 0 or 1023 and changes direction, the timer generates an update event (“UEV” in the above diagram). This update event is…
This week we took another major step in firmware bringup via the janktroller. One of the hardest challenges of this project is to get rotor estimation using only the current and voltage feedback from the motor, which involves using ADCs to sample values. After we found our firmware bug, we started debugging the ADC values we were seeing using Rotate, the GUI that Bolaji made last week and continued firmware debugging. We have also started to work on integrating our…
This week, I worked on making use of our now useful ADC sampling. This gives us current information for each phase, sampled when the low side gate is on in phase with the PWM frequency, which avoids aliasing effects and makes sure that the shunt amplifier output is valid. So far, I have enabled the current feedback for the D Q control loop, so when you command a certain current vector, the controller actually creates that in the motor. I…
This week I worked on the demo aspect of the project. In addition to researching further into the motor and tabletop dyno, I started some initial drawings in CAD for our motor mount and output shafts. We’re going to make some parts out of aluminum to firmly hold the motor assembly in place as we start testing it with higher power. I also found a bike to purchase from Facebook for $40 that we are going to investigate and see…
This week, I wrote an implementation of a flux observer for the janktroller. It uses an integrator to determine the flux that has been put into each phase, and reads the current currently in the phase to sense the ratio between them, which is the flux linkage. This varies as that magnets move around the stator, and with the three flux linkages and some trig you can calculate the electrical position of the rotor. A large benefit of a flux…