Battery Pack Voltage Divider for Floating Reference Diagnosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-voltage battery packs pose challenges in direct voltage measurement due to their high output voltage, requiring galvanic isolation and voltage dividers with series-connected resistors to calculate the output voltage, but existing methods are inefficient and prone to discharge and voltage divider distortion.
Innovation Solution
A battery system with a pack voltage divider and coupling voltage divider, featuring switchable resistors and a floating reference point, allows for accurate voltage measurement and diagnosis of fuses and switches, using high-voltage measurement channels and a control device with A/D converters for digital data conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If galvanic isolation and voltage dividers with series-connected resistors are used to measure high output voltage, then voltage measurement becomes possible, but the system becomes complex and prone to discharge and voltage divider distortion
Solution Approach 1:
The patent introduces a floating reference point as an intermediary element that enables voltage measurement without requiring galvanic isolation. The reference point is electrically connected to both the high-voltage side (via voltage divider) and the low-voltage measurement side, acting as a mediator that transfers voltage information across the isolation barrier without physical contact or complex isolation circuitry.
Solution Approach 2:
The patent extracts the reference point from the traditional ground-referenced measurement system and creates a floating reference that is independent of the high-voltage potential. This extracted reference point can be maintained at a stable potential (e.g., through capacitive coupling or active regulation) while measuring voltages relative to it, simplifying the overall measurement architecture.
2Measurement precision
If voltage dividers with series-connected resistors are used, then high voltage can be measured, but discharge and voltage divider distortion occur
Solution Approach 1:
The patent employs dynamic compensation techniques where the floating reference point potential is actively maintained or adjusted in real-time. This dynamic approach compensates for drift, discharge, and distortion effects in the voltage divider by continuously referencing measurements to a stable floating potential rather than a fixed ground, thereby improving measurement reliability.
Solution Approach 2:
The system incorporates feedback mechanisms where the floating reference point is monitored and adjusted based on measured voltages. This feedback loop ensures that the reference potential remains stable and accurate, compensating for any discharge or distortion in the voltage divider components and maintaining measurement reliability.
3Measurement precision
If traditional voltage measurement methods are used, then voltage can be measured, but diagnostic coverage is limited and dependent on switching states and voltage levels
Solution Approach 1:
The floating reference point architecture provides a universal measurement foundation that works across different switching states and voltage levels. By decoupling the reference from ground and allowing it to float with the high-voltage potential, the system can consistently measure voltages and diagnose faults regardless of the operational state, enabling comprehensive diagnostic coverage with a single measurement system.
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 robust and accurate voltage measurement and diagnosis of battery systems, including contactor-open and contactor-stuck diagnosis, independent of switching states and voltage levels, with increased diagnostic coverage and no need for additional auxiliary sources.
Implementation Method 1
a direct voltage measurement between the poles of the battery pack is difficult. The comparatively high output voltage may for example be measured by way of galvanic isolation. It is also known to provide voltage dividers between the poles of a battery pack, these voltage dividers comprising a multiplicity of series-connected resistors.
Data Source
AI summary
A battery system having a battery pack with a negative pole, a positive pole and a battery cell, a coupling network having a first negative terminal and a first positive terminal, a pack voltage divider, and a coupling voltage divider. The first positive terminal is connectable to the positive pole via a switch. Optionally, the first negative terminal is connectable to the negative pole via a switch. The pack voltage divider includes a two resistors connected between the positive pole and a first reference point. A negative pack measurement resistor and a negative sub-pack measurement resistor are dis-connectable from the negative pole or the first reference point via a switch. A positive coupling measurement resistor and a positive sub-coupling measurement resistor are connected between the first positive terminal and the first reference point. Two resistors are connected between the first negative terminal and the first reference point.