Switch State Detection in Series Power Supply Stacks
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Solution Overview
Problem
Existing methods for monitoring the state of switch elements in vehicle power supplies, particularly in hybrid and electrical vehicles, are not reliable due to the risk of applying large voltages to output terminals, which can damage connected elements.
Innovation Solution
A state determination apparatus comprising a series connection of power supplies, capacitors connected to their electrodes via switch elements, and a microcomputer that determines switch element states by analyzing capacitor voltage values, allowing for the identification of switch failures and stuck states by comparing these values to threshold settings based on power supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply stack is connected to an output terminal by overlapping on time periods of the pairs of switches, then the switch element state can be detected, but a large voltage is applied to the output side which may damage connected elements
Solution Approach 1:
The patent introduces a capacitor as an intermediary element between the power supply stack and the output terminal. The capacitor is charged through the switch elements during overlapping time periods, but the voltage is not directly applied to the output terminal. Instead, the capacitor voltage is measured to infer the switch element states, thus detecting switch status without exposing the output terminal to damaging voltages
Solution Approach 2:
The patent performs preliminary charging of the capacitor through the switch elements before any potential output operation. By charging the capacitor in advance during the overlapping switch period and then measuring its voltage, the system determines switch element states beforehand, preventing direct application of large voltages to the output terminal that could cause damage
2Reliability
If a capacitor is used to charge during overlapping switch time periods, then switch element failures can be detected, but the circuit complexity increases
Solution Approach 1:
The patent designs the capacitor to serve multiple functions: it acts as a charge storage element during switch detection, as a voltage reference for measurement, and as part of the overall power management circuitry. The same capacitor infrastructure supports both the detection function and normal power operations, reducing the need for separate dedicated detection circuits and thereby limiting the increase in overall circuit complexity
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 approach enables reliable detection of switch element failures and stuck states without applying excessive voltage, thereby preventing damage and ensuring accurate monitoring of power supply health.
Implementation Method 1
a capacitor that is connected to each of positive and negative electrodes of the plurality of power supplies via a plurality of switch elements
Data Source
AI summary
A power supply monitoring apparatus includes: a plurality of power supplies that are connected in series; and a capacitor that is connected to each of positive and negative electrodes of the plurality of power supplies via a plurality of switch elements. The power supply monitoring apparatus determines states of the plurality of switch elements, using a voltage value of the capacitor that is acquired when a first switch element of the plurality of switch elements is turned on, the first switch element being connected to one of a total negative-electrode side and a total positive-electrode side of the plurality of power supplies.