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Each of the two motor controllers contains 270uF of low ESR capacitance which requires pre-charging to avoid damage from large inrush currents that would result from directly connecting to the HV battery. This is achieved by a resistor, which A pre-charge resistor is bypassed by a switch controlled by the motor controller interface once the HV bus is charged above 90%to > 90%. The higher Rdson of using power fets compared to a relay is offset by the lack of hold current, resulting in overall lower power loss.
DCDC
The DCDC takes energy from the main back and provides an isolated source of 12V power for all of the low voltage systems in the car. It is centered around a Vicor DCM3623 240W power module, which is capable of delivering up to 16A.
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Panels are connected in two parallel strings each consisting of 5 Nomura MPPTs. Ideal diodes are used to prevent the strings from back feeding each other. The output voltage limit of each MPPT is set such that the maximum voltage of each strings is equal to the max charge voltage of the HV battery, allowing a direct connection to the pack.
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Project | Summary |
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Controller Board | The “brain” of the boards; all boards that require ‘decision making’ or firmware-controlled inputs or outputs will have a controller board | Power Distribution | This board controls the power flow of all other devices in the car. It chooses who gets power, where the source of the power is, and monitors the power drawn Power Select: selects the power source that the car draws power from. It selects between the AUX (usually used only for fans, horn, telemetry, main contactor relays), and DCDC (LV power from main pack) Power Distribution: contains many firmware-controlled load switches that deliver power to all other boards/devices on the vehicles (boards, fans, horn, lights, etc). Also monitors the current draw for each load. Contains many connectors for other boards to plug into | | Disconnects the battery if the voltage falls below a certain threshold. Provides additional protection features, including | Centre Console | Serves as the hub of communication between the driver and the car. Displays useful information (speed, battery state, left/right turn signals, Battery Protection System warnings) to the driver in the form of LEDs and 7-segment displays. It also receives input from 6 buttons, allowing the driver to Power On the vehicle, switch drive states (Drive, Neutral, Reverse), and enable/disable regen braking and hazard lights. | Motor Controller Interface (MCI) | Talks to motor controllers, we control the motors/get motor information through this board. | BMS Carrier | This board is responsible for protecting the battery. Its responsibilities are: Logging Voltage, Current, Temperature Calculating the state of charge Detecting battery faults and acting upon them
| BMS AFE | Used to measure cell voltage and temperatures from each individual battery module, and also keep the cells balanced | BMS Current Sense | Measures the total current flowing from the battery pack. | DCDC | Converts the high voltage (110-150V) to the necessary low voltage of 12V nominal (ends up being 13-14V) | Pedal | Measures the angle of both pedals in the car (accelerator and brakes). This information is used to know how much each pedal is pressed, and then use this information to execute some functions (e.g if the accelerator is not pressed then regen braking will occur; if brakes are pressed, then brake lights should turn on) | Steering | Used for measuring steering angle as well as controls present on the stalk (lights, signals, horn). | Solar Sense/MPPTs | Solar sense: Measures the array module and array voltage, temperature, current MPPT: Converting high current low voltage output from the solar panels into low current high voltage power compatible with our batteries and motors | Steering Stalk | The physical steering stalk that the driver uses, taken off an old vehicle, currently in the bay. It contains its own circuitry that must be understood such that we can interface with it and understand how to read its inputs. | Motor Testing | To test the motor and motor controller work correctly | Electrical Systems PVDR/VDR | Comprehensive design report including technical documents mechanical systems, electrical systems, batteries, and solar cells. |
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