On-Vehicle Battery Charger Monitoring via Active Interruption
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Solution Overview
Problem
Existing on-vehicle battery chargers for plug-in electric vehicles lack effective monitoring capabilities to assess charging efficiency, leading to potential inefficiencies and faults that are not promptly detected.
Innovation Solution
A method involving a passive charger monitoring routine to estimate charging efficiency and an active routine to determine active charging efficiency by interrupting current flow, allowing for evaluation of charging performance and fault detection in the battery charger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If passive charger monitoring routine is used to estimate charging efficiency, then monitoring capability is improved, but measurement precision deteriorates due to indeterminate results
Solution Approach 1:
The system performs preliminary data collection during passive monitoring mode, gathering commanded input power and electric power at the battery during charger operation. This preliminary action prepares the necessary measurements before the active interruption test, ensuring that when precision is needed, all required data is already available or can be quickly obtained.
Solution Approach 2:
The monitoring system dynamically transitions between two operational modes: passive monitoring mode for normal operation and active interruption mode for precise measurement. The controller switches between these modes based on monitoring needs, allowing the system to adapt its measurement approach rather than being stuck with a single static method.
2Measurement precision
If active charging efficiency determination is used by interrupting current flow, then measurement precision is improved, but productivity deteriorates due to charging interruption
Solution Approach 1:
The active interruption test is performed periodically rather than continuously, allowing the system to maintain high charging productivity during normal operation while occasionally pausing to perform precise efficiency measurements. This periodic approach minimizes the impact on overall charging speed while still providing accurate monitoring data at regular intervals.
Solution Approach 2:
The monitoring system uses the battery itself as the test load during active interruption mode. When the charger is interrupted, the battery's natural discharge characteristics provide the test conditions needed for measurement, eliminating the need for external test equipment or additional test loads that would complicate the system.
3Reliability
If comprehensive monitoring is implemented to evaluate charging performance, then reliability is improved, but device complexity increases
Solution Approach 1:
The controller serves multiple functions: it manages normal charging operation, executes passive monitoring routine, performs active interruption tests, calculates charging efficiency, and controls the charger based on results. By making the controller multi-functional rather than adding separate dedicated hardware for each function, the system achieves comprehensive monitoring without proportionally increasing complexity.
Solution Approach 2:
The patent combines the monitoring functions with the existing charger control system. The same controller that manages charger operation also performs monitoring, data collection, efficiency calculation, and fault detection. This merging of functions into a single integrated system reduces overall system complexity compared to having separate monitoring hardware.
Data Source
AI summary
A method for monitoring an on-vehicle battery charger includes estimating a charging efficiency of the battery charger. Upon achieving an indeterminate result related to the estimated charging efficiency of the battery charger, a commanded input power to the battery charger and an electric power at the on-vehicle battery during operation of the battery charger are determined. Flow of electric current through the battery charger is interrupted, and electric power flow from the on-vehicle battery is determined. An active charging efficiency of the battery charger is determined based upon the commanded input power to the battery charger, the electric power at the on-vehicle battery during operation of the battery charger and the monitored electric power flow from the on-vehicle battery when the flow of electric current through the battery charger is interrupted. Charging performance of the battery charger is evaluated based upon the active charging efficiency.