Vehicle Power Source Pre-Charging via Dynamic Boost Control
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Solution Overview
Problem
The existing power source systems for vehicles face challenges in completing pre-charging of capacitors within a short time without causing a voltage drop in the auxiliary power source, which can lead to unstable operations of connected auxiliary devices.
Innovation Solution
A power source system that includes a main power source, an auxiliary power source, a power converter, a relay, a boost converter, and a controller, where the controller acquires data on the chronological changes of voltage and current of the auxiliary power source to specify a relationship between them, allowing the boost converter to operate at a high output without dropping the voltage below a predetermined threshold, ensuring stable pre-charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the boost converter operates at high output to complete pre-charging quickly, then the pre-charging time is reduced, but the voltage of the auxiliary power source drops below the threshold causing unstable operation of auxiliary devices
Solution Approach 1:
The patent implements dynamic control of the boost converter's output current based on real-time monitoring of auxiliary power source voltage. The controller adjusts the output current dynamically: when voltage is above threshold, higher current flows to charge capacitor faster; when voltage approaches threshold, current is reduced to maintain stable operation of auxiliary devices. This dynamic adjustment resolves the contradiction between fast pre-charging and system stability.
Solution Approach 2:
The system incorporates feedback control by continuously monitoring the voltage of the auxiliary power source and using this information to regulate the boost converter's output. The controller receives voltage feedback and adjusts the pre-charging current accordingly, ensuring that the voltage remains above the predetermined threshold while still achieving efficient pre-charging. This feedback mechanism balances speed and stability requirements.
2Reliability
If the system limits the boost converter output to maintain auxiliary power source voltage above threshold, then auxiliary devices operate stably, but pre-charging time increases
Solution Approach 1:
Rather than using a fixed current limit, the system employs dynamic current adjustment based on real-time voltage conditions. The boost converter operates at high current when voltage allows, maximizing pre-charging speed, and reduces current only when necessary to maintain the voltage threshold. This dynamic approach optimizes both productivity and reliability.
Solution Approach 2:
The system changes the operating parameters of the boost converter dynamically during the pre-charging process. The output current parameter is adjusted based on the voltage state of the auxiliary power source, allowing the system to achieve high pre-charging speed when conditions permit while ensuring stability when voltage approaches critical levels.
3Productivity
If a large current flows into the capacitor through the system main relay at turn-on, then the capacitor charges quickly, but contact melting occurs in the system main relay
Solution Approach 1:
The boost converter acts as an intermediary device that charges the capacitor before the system main relay is activated. By using the auxiliary power source and boost converter to pre-charge the capacitor, the system avoids the harmful large inrush current that would otherwise flow through the system main relay contacts, preventing contact melting while still achieving rapid capacitor charging.
Solution Approach 2:
The system performs preliminary charging of the capacitor through the boost converter before activating the system main relay. This preliminary action prepares the capacitor in advance, so that when the main relay closes, the harmful large current surge is avoided. The pre-charging is completed beforehand, eliminating the risk of contact melting during relay operation.
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
This system enables stable and efficient pre-charging of capacitors within a short time, preventing voltage drops in the auxiliary power source and ensuring stable operations of connected auxiliary devices.
Implementation Method 1
a boost converter having a low voltage terminal thereof connected to the auxiliary power source and a high voltage terminal thereof connected to the power converter
Implementation Method 2
The power converter includes a capacitor connected between a positive electrode and a negative electrode of the main power source. The capacitor is provided for smoothing a current supplied from the main power source or for temporarily storing power energy
Data Source
AI summary
A power source system may include a main power source, a power converter including a capacitor, a relay configured to switch between connection and disconnection between the power converter and the main power source, an auxiliary power source, a boost converter having a low voltage terminal thereof connected to the auxiliary power source, and having a high voltage terminal thereof connected to the power converter without interposing the relay, and a controller configured to pre-charge the capacitor prior to placing the relay in a connected state. The controller may be configured to specify a relationship between a voltage and a current of the auxiliary power source based on data of chronological changes of the voltage and the current of the auxiliary power source, and control the boost converter based on the relationship such that a voltage of the auxiliary power source does not fall below a predetermined voltage threshold.