Pilot Control Circuit for Low Auxiliary Battery Charging
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Solution Overview
Problem
Electrified vehicles with low auxiliary battery voltage cannot be charged by an off-board charging station, as the charging process requires sufficient auxiliary battery voltage to operate the control systems, creating a dependency on initial charging of the auxiliary battery before charging can commence.
Innovation Solution
A control pilot circuit with a first and second switch, powered by the auxiliary battery, adjusts the pilot signal voltage based on the battery voltage threshold, allowing communication and power transfer between the vehicle and charging station, enabling charging of both the auxiliary and traction batteries without requiring pre-charge of the auxiliary battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charging process requires sufficient auxiliary battery voltage to operate the control systems, then the charging process can be controlled reliably, but vehicles with low auxiliary battery voltage cannot be charged
Solution Approach 1:
A voltage conversion circuit is introduced as an intermediary component between the auxiliary battery and the controller. This circuit converts the low auxiliary battery voltage into a higher voltage suitable for controller operation, enabling the controller to function reliably even when the auxiliary battery voltage is low. The voltage conversion circuit acts as a mediator that resolves the voltage mismatch problem.
Solution Approach 2:
The system dynamically changes the voltage parameter by using a voltage conversion circuit that can convert between different voltage levels. When the auxiliary battery voltage is low, the circuit converts it to a higher voltage for the controller. The system also uses voltage threshold detection to determine when to initiate charging, changing the operational parameters based on battery state.
2Reliability
If separate initial charging of the auxiliary battery is required before charging can commence, then the control systems can operate properly, but the charging process becomes more complex and time-consuming
Solution Approach 1:
The patent merges the auxiliary battery charging process with the main charging process. Instead of requiring separate sequential charging steps, the system enables both batteries to be charged simultaneously through integrated control. The voltage conversion circuit allows the controller to manage the charging process while the auxiliary battery is being charged, eliminating the need for separate pre-charging operations.
Solution Approach 2:
The system enables self-service charging where the voltage conversion circuit automatically adjusts voltages and the controller initiates charging operations without requiring external pre-charging equipment or manual intervention. The charging system serves itself by converting voltages as needed and managing the entire charging process internally.
3Reliability
If the auxiliary battery voltage must exceed a threshold to enable charging, then the controller can be powered reliably, but vehicles with dead or low auxiliary batteries are excluded from charging
Solution Approach 1:
The voltage conversion circuit serves as a mediator that bridges the gap between low auxiliary battery voltage and the higher voltage required by the controller. It converts the insufficient voltage from the auxiliary battery into adequate voltage for controller operation, allowing the controller to power itself during the charging process without requiring external pre-charging.
Solution Approach 2:
The voltage conversion circuit performs preliminary voltage conversion action before the controller needs to operate. By pre-converting the low auxiliary battery voltage to a higher level, the system ensures the controller can immediately begin operation when charging is initiated, without waiting for the auxiliary battery to reach a threshold voltage.
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
Enables the charging of vehicles with low or dead auxiliary batteries by allowing power transfer and communication with the charging station, streamlining the charging process and eliminating the need for separate initial charging of the auxiliary battery.
Implementation Method 1
a first switch arranged between the pilot pin and a ground... close the first switch using power from the auxiliary battery to induce a first voltage change in the pilot signal
Implementation Method 2
a second switch arranged between the pilot pin and the ground... close in response to the voltage of the auxiliary battery being less than the threshold to induce the first voltage change in the pilot signal
Data Source
AI summary
A vehicle includes a traction battery, an auxiliary battery, and a charge port configured to mate with a connector of a charging station. The charge port has a pilot pin. A control pilot circuit includes a first switch arranged between the pilot pin and a ground. The pilot circuit further includes a second switch arranged between the pilot pin and the ground. The second switch is configured to close in response to the voltage of the auxiliary battery being less than the threshold to induce the first voltage change in the pilot signal, and open in response to the voltage of the auxiliary battery exceeding the threshold.