Voltage Measuring Apparatus with Reference Voltage Calibration
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Solution Overview
Problem
Existing voltage measurement methods for high-voltage batteries, which rely on an average of unit cell voltages as a reference, become unreliable when cell voltages within a block vary, leading to inaccurate error detection and correction.
Innovation Solution
A voltage measuring apparatus with a reference voltage generating part using a series-connected circuit of a resistor and diode, along with an A/D conversion part, to digitize cell and reference voltages, and a communication part to transmit these signals for comparison with theoretical values, enabling accurate error detection and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the average of unit cell voltages is used as a reference voltage for error detection, then the voltage measurement error can be detected, but the reference voltage becomes unreliable when cell voltages vary significantly within a block
Solution Approach 1:
The patent introduces a dedicated reference voltage generating circuit as an intermediary component that produces a stable reference voltage independent of cell voltage variations. This reference voltage circuit uses a voltage reference IC and resistor divider network to generate a reliable reference voltage that serves as a mediator between the measurement system and the varying cell voltages, resolving the contradiction between measurement precision and reference reliability.
Solution Approach 2:
The patent segments the voltage measurement system into independent functional blocks: a reference voltage generation block, an A/D conversion block, and a measurement block. By separating the reference voltage generation from the cell voltage measurements, the system ensures that variations in cell voltages do not affect the reference voltage stability, thus maintaining both measurement precision and reference reliability.
2Device complexity
If analog voltage signals are directly converted to digital signals without precise reference voltage, then the conversion process is simple, but the digitized voltage signals contain errors
Solution Approach 1:
The patent applies preliminary action by generating and stabilizing the reference voltage before the A/D conversion process. The reference voltage circuit is configured to establish a stable voltage baseline prior to digitization, ensuring that the subsequent A/D conversion operates with a reliable reference. This preliminary stabilization of the reference voltage prevents measurement errors without adding significant complexity to the conversion process.
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 allows for highly accurate calibration of voltage detection accuracy across each voltage detecting unit, effectively correcting errors and ensuring precise monitoring of cell voltages, even when cell voltages vary within a block.
Implementation Method 1
a reference voltage generating part having a series-connected circuit of a resistor and at least one diode to output a reference voltage that is generated across the diode when a voltage is applied across the series-connected circuit
Data Source
AI summary
In a voltage measuring apparatus for a plural battery according to the present invention, each of voltage detecting ICs (21-1) to (21-5) connects a switch SW1 to a reference voltage generator 24 and supplies a reference voltage Vf from the reference voltage generator 24 to an A/D converter 26. The A/D converter 26 digitizes the reference voltage Vf, which is transmitted to a main microcomputer 33. The main microcomputer 33 finds a theoretical value of the reference voltage according to an ambient temperature, compares the theoretical value with the measured value of the reference voltage Vf, and determines whether or not the voltage detecting accuracy of the first voltage detecting IC (21-1) is good.