SolarPowerSystem
SolarPowerSystem — A solar power system model
Description
The SolarPowerSystem models a solar power system including power generated as function of time and distance from the sun, and includes shadow modeling by celestial bodies. The model allows you to configure the power generated by the solar arrays, and the power required by the spacecraft bus.
For a complete descripton of how to configure all Resources required for electric propulsion modelling, see the Tutorial named Chapter 12, Electric Propulsion
See Also ElectricTank, ElectricThruster, NuclearPowerSystem
Fields
| Field | Description | ||||||||||||
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| AnnualDecayRate |
The annual decay rate of the power system.
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| BusCoeff1 |
Coefficient of power required by spacecraft bus.
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| BusCoeff2 |
Coefficient of power required by spacecraft bus.
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| BusCoeff3 |
Coefficient of power required by spacecraft bus.
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| EpochFormat |
The epoch format for the PowerInitialEpoch field.
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| InitialEpoch |
The initial epoch of the system used to define power system elapsed lifetime.
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| InitialMaxPower |
The maximum power generated at the PowerInitialEpoch.
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| Margin |
The required margin between power left after power bus, and power used by the propulsion system.
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| ShadowBodies |
A list of celestial bodies for use in the shadow computation. A body cannot be added more than once.
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| ShadowModel |
The model used for shadow computation in the Solar System Power Model.
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| SolarCoeff1 |
Coefficient of power created by solar power system.
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| SolarCoeff2 |
Coefficient of power created by solar power system.
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| SolarCoeff3 |
Coefficient of power created by solar power system.
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| SolarCoeff4 |
Coefficient of power created by solar power system.
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| SolarCoeff5 |
Coefficient of power created by solar power system.
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Remarks
Computation of Base Power
The SolarPowerSystem models power degradation as a function of time. You must provide a power system initial epoch, the power generated at that epoch, and an annual power decay rate. Additionally, the AnnualDecayRate field models the power degredation on a per year basis. The base power is computed using
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where "tau" is the power AnnualDecayRate, P_0 is InitialMaxPower, and "delta t" is the elapsed time between the simulation epoch and InitialEpoch.
Computation of Bus Power
The power required by the spacecraft bus for all subsystems other than the propulsion system is computed using
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where A_Bus, B_Bus, and C_Bus are BusCoeff1, BusCoeff2, and BusCoeff3 respectively and r is the distance from the Sun in Au.
Computation of Power Available for Propulsion
The solar power model scales the base power based on a polynomial function in terms of the solar distance. Total power is compute using
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where P_Sun is the percent sun ( full sun is 1.0, no sun is 0.0), r is the distance from the Sun in Au, and C_1 is SolarCoeff1 and so on. Thrust power available for electric propulsion is finaly computed using
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Where "delta M" is power Margin.
Shadow Modelling and Discontinuities
Note that when modeling shadows for a solar power system, discontinuities in the force model can occur when the power avialable for propulsion is less than a thruster's minimum useable power setting. As a spacecraft passes from penumbra to umbra, and power avialable for thusting goes to zero, thrust power causes thrust acceleration to discontinuously terminate, causing issues when using adaptive step integrators. In this case, there are a few options. You can configure any itegrator to use fixed step integration by setting the ErrorControl to None. Or you can configure the integrator to continue propagating if a bad step, in this case a small discontinuity, occurs. See the Propagator reference material for more information.
Examples
Create a SolarPowerSystem and attach it to a Spacecraft.
% Create the Solar Power System
Create SolarPowerSystem SolarPowerSystem1
% Create a spacecraft an attach the Solar Power System
Create Spacecraft DefaultSC
DefaultSC.PowerSystem = SolarPowerSystem1
BeginMissionSequence
For a complete descripton of how to configure all Resources required for electric propulsion modeling, see the Tutorial named Chapter 12, Electric Propulsion.