Voltage Adjusting Apparatus Malfunction Protection
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Solution Overview
Problem
Existing voltage adjusting apparatuses for hybrid vehicles face reliability issues due to continuous energy consumption by high-voltage batteries when the control unit malfunctions, and increased costs from duplex communication lines in self-diagnostics systems.
Innovation Solution
A voltage adjusting apparatus with a low-voltage system and high-voltage system that includes a low-voltage control unit, high-voltage power supply circuit, equalizing unit, isolating unit, and communication lines to monitor malfunctions and prevent over-discharging, using timers to manage malfunction judging periods and control power supply, reducing the need for duplex communication lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the equalizing unit continues to perform equalizing action during engine OFF period, then the dispersion of SOC between unit cells is reduced, but the low-voltage battery is over-discharged and loses energy to start the engine
Solution Approach 1:
The control unit continuously monitors the voltage of the low-voltage battery and adjusts the equalizing action accordingly. When the battery voltage drops below a predetermined threshold, the control unit automatically stops the equalizing action, preventing over-discharge while still allowing equalization when sufficient energy is available
Solution Approach 2:
The system uses the available energy from the low-voltage battery to perform equalization during engine OFF periods when no other loads are present, effectively utilizing idle time and available energy resources without requiring external power sources
2Use of energy by moving object
If the control unit stops functionally during adjusting (equalizing), then the low-voltage battery is protected from over-discharging, but the high-voltage battery may have a malfunction due to continuous energy consumption
Solution Approach 1:
The control unit performs preliminary checks of the low-voltage battery voltage before initiating equalizing action. By predicting whether sufficient energy will be available throughout the equalization process, the system prevents both over-discharge and potential malfunctions from incomplete equalization
Solution Approach 2:
The equalizing action is made dynamic rather than static - the control unit continuously adjusts the equalization process based on real-time battery voltage conditions, allowing the system to adapt to changing energy availability and prevent both over-discharge and malfunction scenarios
3Reliability
If a duplex communication line is used for fail-safe monitoring, then the reliability of self-diagnostics is improved, but the cost of the electronic control apparatus is increased
Solution Approach 1:
The single communication line performs multiple functions: it transmits control signals from the control unit to the equalizing unit, receives status information from the equalizing unit, and enables fail-safe monitoring through timing-based diagnostics. This multi-functional use eliminates the need for separate duplex communication lines while maintaining reliability
Data Source
AI summary
For providing a reliable voltage adjusting apparatus in low cost, a low-voltage control apparatus controls a high-voltage power supply circuit to be switched power off by transmitting a power-off signal through a second communication line arranged between the high-voltage power supply circuit and itself through an isolation unit when an information signal from an equalizing apparatus is not transmitted within a predetermined first malfunction judging period. The equalizing apparatus stops an equalizing process in itself when the information signal from the low-voltage control unit.