Battery-Backed DC Link Startup Control for Weak External Power
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Solution Overview
Problem
Transport refrigeration units face challenges in reliably supplying electrical power to components during startup processes, especially when the external power source's capability is insufficient, leading to potential failures in completing the startup across various operational scenarios.
Innovation Solution
An apparatus comprising a controller, a load, a battery, and a DC link, where the controller evaluates startup and source capability criteria to switch between protected and unprotected modes, with the battery providing power to the DC link only when the external source is incapable of meeting the required current demands during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery provides power during startup to ensure reliable operation, then the startup reliability is improved, but the battery degradation increases
Solution Approach 1:
The system dynamically switches between two operational modes: protected startup mode (battery provides power) and unprotected startup mode (external power source provides power). The controller evaluates both component startup criteria and source capability criteria in real-time to determine which mode to activate, making the power supply configuration adaptive rather than fixed.
Solution Approach 2:
The system changes the operational parameters of the battery based on evaluated conditions. When component startup criteria are met but source capability criteria are not met, the battery is activated to provide power. When both criteria are met, the battery remains inactive. This parameter change approach allows the system to optimize between reliability and battery lifetime based on real-time conditions.
2Duration of action of moving object
If the external power source is used during startup, then the battery degradation is reduced, but the startup reliability may be compromised when external power is insufficient
Solution Approach 1:
The controller continuously evaluates source capability criteria (assessing whether the external power source can meet startup power demands) and component startup criteria (assessing whether the electrical component is ready for startup). Based on this feedback evaluation, the controller automatically selects the appropriate power supply mode, ensuring that startup reliability is maintained while minimizing unnecessary battery discharge.
Solution Approach 2:
The system transitions between static power supply configurations by implementing dynamic mode switching. The unprotected startup mode is selected when external power is sufficient, preserving battery life. The protected startup mode is selected when external power is insufficient, ensuring reliable operation. This dynamic adaptation resolves the contradiction between battery preservation and startup reliability.
3Reliability
If the battery is used to supply power during startup, then the startup process completes reliably, but the battery discharge increases leading to faster degradation
Solution Approach 1:
The system alters the power supply state of the battery based on evaluated conditions. By changing the parameter of battery activation status (active vs. inactive) based on source capability and component startup criteria, the system ensures reliable startup when necessary while minimizing energy loss through unnecessary discharge when external power is sufficient.
Solution Approach 2:
The system applies different power supply strategies to different operational scenarios. Instead of using a uniform approach, it locally adapts the power supply configuration: protected mode is applied when external power is insufficient, and unprotected mode is applied when external power is sufficient. This local quality approach optimizes the balance between startup reliability and battery energy conservation.
Data Source
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AI summary
The present disclosure relates to an apparatus 100 comprising a controller 190, a load 180, a battery 150, and a DC link 121. The DC link 121 is coupled to the load 180, couplable to the battery 150, and couplable to an external power source 175. The load 180 comprises an electrical component 115. The controller 190 is configured to: evaluate 302 a component startup criterion relating to whether the electrical component 115 is performing a startup process, evaluate 304 a source capability criterion relating to a capability of the external power source 175 to supply power to the DC link 121, and in response to a determination 326, 348 that the component startup criterion has been met and the source capability criterion has not been met, operate 306 the apparatus 100 in a protected startup mode in which the battery 150 provides power to the DC link 121.