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The RMS Inverter acts as the motor controller for the car. It takes in a DC voltages and outputs three frequency controlled AC signals to the motor. The inverter also handles some safety by having internal regulations on current, voltage, and temperature. These maximum and minimum settings (as well as some relating to calibration and performance) are controlled via EEPROM (Electrically Erasable Programmable Read-only Memory) parameters. Because this project involves several off-the-shelf parts, it revolve more around testing and validation than design. Extensive debugging journal can be found here.
T.4.2.5/T.4.3.3 - Stops power to motors in case of implausibility
EV.5.2 - No direct connection between motor and accumulator
EV.6.8.1 - Must have two tractive system measuring points connected to inverter supply lines
Cascadia Motions Rinehart PM100dz Motor Controller
PM CM and RM Hardware User's Manual (V3_7).pdf
Emrax 228 - High Voltage
RMS firmware is updated and flashed using C2Prog. Firmware versions can be found using Cascadia Motion’s Firmware Archive. The EEPROM parameters can be programmed using the RMS GUI. Each version of the GUI has a symbols file labeled with its release date. It is crucial that the symbols file date is compatible between the firmware and GUI. The current symbols file being used is “defsyms_20180316_G3.txt.” Firmware downloads can be found on the RMS product page.
CANalyzer is a simulation and analysis tool. Essentially, it allows for us to send torque commands to the motor and test it on the bench before connecting it to the pedal and putting it on the car. This can be done live using the customizable GUI, or can be scripted using the visual sequencer. It also allows for us to read and log all of the data that the inverter sends out, such as temperatures, DC bus voltage, speed, and torque feedback.
Other than the program itself, the main code being used is entry.can. This file is ran at the beginning of logging and configures the RMS to send and receive messages with the program. Other essential files include the CANalyzer project file and the .database (database) file that decodes each individual symbol from the CAN messages.
The VECTOR suite includes other useful tools, such as the GUI editor and Database editor that can be used to change the interface for different testing applications. The VECTOR licensing can be complicated and should be resolved early in the design process.
The LV connecters comprise of two AMP seals. Connector J1 connected the CAN and LV power (12V). There are two CAN lines: On SN1, we used one for connecting to the RMS firmware GUI and one for connecting to CANalyzer (or to the next CAN module on the actual car). We made a water proof connecter where we could talk to the firmware after assembly, in case we needed to clear faults during competition. Connector J2 is used for the resolver harness which allows the inverter to track the position and speed of the motor.