The satellite is powered by 3 solar panels (think 3 variable voltage sources). Each solar panel needs a reverse current blocking diode on its output. These diodes are being chosen and tested in a different project (Fault Risk Analysis), but we also need to decide where physically they should go. Should they be on the solar panels themselves? Should they be on the EPS board? Does it literally not matter? This is a very important component, so do some research and make a decision so we can build it and start testing it.
When you’re done, you can formalize this into a Trade about including vs not including subsystem level fuses. You can find the structure of a Trade here: (don’t put it in the actual trades database yourself, I’ll do that when you’re done. For now, keep everything under the Notes section of this page)
Goal: To research where the Diodes should go, by providing an outline of factors to consider and through researching on individual components and how placing a diode in their vicinity would have an effect (if any). The end goal is to list potential spaces and explain their rationale.
Scope: Limited to simply understanding if there’s an effect, to be used in making a decision on the placement of the diodes.
Relevant Resources: https://ntrs.nasa.gov/api/citations/19670022708/downloads/19670022708.pdf
This trade aims to determine the optimal placement for the reverse current blocking diodes, which are placed in series with the solar panels panels, in the satellite’s power system.
Functional Integrity: Placement must guarantee optimal functionality of the reverse current blocking diodes, to ensure seamless operation in practice.
Component Safety: The placement must not compromise the integrity of neighboring components, mitigating any potential risks of component or potentially system and/or power failure.
Efficiency: The selected placement should aim to minimize power losses and dissipation, optimizing energy utilization.
Malfunction Identification: Placement must facilitate easy identification of diode or panel malfunction (given this occurs) to enable its remote mitigation.
EPS Board - place the diodes on the EPS board
Batteries/Solar Panels - place the diodes between the batteries and solar panels
Solar Panels - place the diodes directly on the solar panels
| Criteria | Solar Panel Placement | EPS Board Placement | Between Batteries and Solar Panels |
|---|---|---|---|
| Advantages | Direct placement on the solar panel reduces voltage drops and losses. | ||
| Source: | Centralized placement would ease remote troubleshooting, as all the diodes would be nested together. | ||
| Source: | Shorter wires run between the components, which would reduce resistance. | ||
| Source: | |||
| Simplified wiring reduces the complexity of setting up the wires and potential electrical faults. | |||
| Source: | Centralized placement would ease the identification of the current blocking diodes. | ||
| Source: | Direct placement close to the power source (battery and solar panels), enhances simplicity. | ||
| Source: | |||
| Disadvantages | Limited space may restrict the addition or integration of additional components on the satellite. | ||
| Source: | Wiring complexity between the diodes and solar panels. | ||
| Source: | Limited space may restrict the addition or integration of additional components on the satellite. | ||
| Source: | |||
| Exposure of the diodes to space, harsh space environment. | |||
| Source: | Potential for power dissipation due to the wires in the connection between the components. | ||
| Source: | Exposure of the diodes to space, harsh space environment. | ||
| Source: | |||
| Tradeoffs | Simplified wiring/Reduced Resistance | ||
| vs. | |||
| Limited Space / Harsh Conditions | Centralized placement | ||
| vs. | |||
| Power dissipation / Wiring Complexity | Reduced resistance | ||
| vs. | |||
| Limited Space / Harsh Conditions | |||
| Decisions on the diodes would address the harsh conditions (out of scope) |
There may not be the need for other components either (out of scope)
Factor: Wire runs between battery and panel, since the diode is on the panel. | Centralized placement may cause a fault to affect all the three components at once.
Power dissipation may be dealt with wire choice or design (out of scope) | There may not be the need for other components either (out of scope)
There may not be the need for other components either (out of scope)
Factor: Wire runs between panel and battery and diode | | Evaluation | Less wire, addresses the resistance and power dissipation issue. | Creates the power dissipation issue and centralized placement may not be the best. | Tradeoff compared to direct placement on the solar panel option. | | | | | |
General References used to finetune decisions in this Evaluation