CubeSat Multiport Converter With Single-Inductor MPPT
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Solution Overview
Problem
CubeSats face challenges with power generation due to varying solar irradiation profiles across PV panels, leading to inefficiencies and increased weight from multiple inductors in existing EPS architectures, which can result in energy losses and reduced reliability of semiconductor devices.
Innovation Solution
A compact multiport converter using a single inductor for energy transfer from PV panels to Li-Ion batteries, along with a series-connected half-bridge module topology and a boost converter, optimized for maximum power point tracking and incorporating a power-down mode to reduce operational stresses on semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple DC-to-DC converters with multiple inductors are used to maximize solar energy harvest, then power conversion efficiency is improved, but device weight and volume increase
Solution Approach 1:
The patent combines multiple DC-to-DC converter functions into a single multiport converter that handles multiple PV panels and battery interfaces. This consolidation eliminates the need for separate inductors for each converter, reducing overall weight while maintaining the capability to perform maximum power point tracking for multiple panels simultaneously.
Solution Approach 2:
The multiport converter is designed to perform multiple functions: it interfaces with multiple PV panels with different irradiation profiles, performs maximum power point tracking for each panel, charges/discharges batteries, and provides load voltage regulation. This single device replaces what would traditionally require multiple specialized converters and inductors.
2Power
If multiple inductors are used in DC-to-DC converters, then power conversion capability is improved, but energy losses increase due to added impedance
Solution Approach 1:
By merging multiple inductor functions into a single shared inductor in the multiport converter, the total impedance in the circuit is reduced compared to having multiple separate inductors. This single inductor design maintains adequate power conversion capability while minimizing resistive losses.
3Adaptability or versatility
If isolation transformer is used in multiport converter, then AC power transfer is enabled, but device footprint and mass increase
Solution Approach 1:
The patent removes the isolation transformer component from the multiport converter design. Instead of using electromagnetic transformation through a transformer, the system achieves AC power transfer and isolation through galvanically isolated DC-to-DC conversion stages, eliminating the bulky transformer while maintaining functional capabilities.
4Reliability
If continuous operation mode is used for power converters, then power supply reliability is maintained, but semiconductor device lifespan is reduced due to operational stresses
Solution Approach 1:
The patent implements a dynamic power-down mode that allows the multiport converter to switch between active and standby states based on operational needs. During eclipse periods or low-power conditions, the converter can enter a low-power state with reduced switching activity, minimizing thermal and electrical stresses on semiconductor devices while maintaining the ability to quickly resume full operation when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves efficient solar energy harvesting while reducing the footprint and weight of the EPS, enhancing fault-tolerance and extending the lifespan of semiconductor devices by minimizing electrical and thermal stresses.
Implementation Method 1
The power generated by each panel depends on the irradiation of each PV panel
Implementation Method 2
A compact multiport converter using a single inductor for energy transfer from PV panels to Li-Ion batteries
Data Source
AI summary
The application discloses a compact, multiport converter for interfacing photovoltaic (PV) panels to an energy storage system of a CubeSat. The multiport converter includes a series of connected half-bridge modules, fed by PV panels, that supplies the energy storage system. Further, a control strategy allows the multiport converter to extract a maximum amount of solar power from PV panels under varying irradiation conditions. One example multiport converter includes a multiple-input multiple-output converter that achieves a smaller footprint by utilizing a single inductor for transferring energy. Some aspects also enhance a fault-tolerance capability of CubeSats using a new EPS architecture, for example, by providing independent converters for maximum power point tracking of PV panels. The fault-tolerance capabilities are further enhanced by a new power-down mode for generation and load-side converters.