Vehicle Power Management Switch Voltage Equalization
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Solution Overview
Problem
Conventional power management systems for vehicles fail to continuously supply power from a high-voltage circuit to a low-voltage circuit when a power converter fails, leading to potential vehicle stoppages and increased costs due to dual-system configurations.
Innovation Solution
A power management apparatus with a switch and power management section that controls a motor-generator to equalize the voltage difference between high-voltage and low-voltage electric power storage devices, allowing the switch to transition from a non-conduction to a conduction state when a power converter failure is detected, ensuring continuous power supply to vehicle electric apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual-system configuration with two power converters is used in preparation for failure, then reliability is improved, but cost and device complexity are remarkably increased
Solution Approach 1:
The switch is pre-configured between the high-voltage and low-voltage circuits but remains in a non-conductive state during normal operation. When power converter failure is detected, the switch transitions to a conductive state, enabling the high-voltage circuit to directly supply power to the low-voltage circuit without requiring a second power converter. This preliminary preparation allows failover without duplicating the entire power converter system.
2Reliability
If the switch transitions to conduction state immediately upon failure detection, then power supply continuity is improved, but voltage difference between circuits may cause harmful effects
Solution Approach 1:
Before the switch transitions to the conductive state, the power management section performs preliminary voltage equalization by controlling the motor-generator to adjust the voltage of the high-voltage circuit. This ensures that the voltage difference between the high-voltage and low-voltage circuits is minimized before power transfer begins, preventing damage to electrical components while maintaining continuous power supply.
Solution Approach 2:
The system dynamically changes the voltage parameter of the high-voltage circuit by controlling the motor-generator's operation mode (motor mode or generator mode). This parameter adjustment equalizes the voltage between the high-voltage and low-voltage circuits before the switch closes, eliminating the harmful voltage difference that would otherwise damage electrical components during failover.
3Productivity
If power is supplied from high-voltage circuit to low-voltage circuit during normal operation, then power generation efficiency is improved, but voltage difference may cause harmful effects when switch operates
Solution Approach 1:
The power management section continuously monitors the voltage levels of both the high-voltage and low-voltage circuits. Based on this feedback, it controls the motor-generator to adjust the high-voltage circuit's voltage, ensuring equalization before the switch transitions to the conductive state. This feedback mechanism allows efficient power utilization while preventing voltage difference damage during switch operation.
Data Source
AI summary
The power management apparatus provided in a vehicle includes: a switch 6 for bringing a state between the first and second electric power storage devices 1 and 2 into a non-conduction state during a normal operation and switching the state therebetween to a conduction state when a failure of the power converter 4 is detected; and a power management section 7 for controlling the motor-generator 3 so that a difference between voltages of the first and second electric power storage devices 1 and 2 is equal to or smaller than a predetermined voltage difference before the switch 6 is operated to perform switching from the non-conduction state to the conduction state.