Sampling Transformer Voltage Clamp for Battery Cell Telemetry
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Solution Overview
Problem
Lithium ion battery cells operate suboptimally due to voltage imbalances caused by internal leakage resistance mismatches, leading to overcharging or undercharging, which can result in non-optimal conditions and render the battery inoperative.
Innovation Solution
A cell telemetry system that uses a sampling transformer, pulse driven switch, voltage clamp mechanism, and synchronized sampling switch to balance volt-seconds and force an average magnetizing current to zero amperes, allowing for accurate measurement of high voltage sources by alternately activating and deactivating these components according to a clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sampling transformer is used to measure high voltage sources, then voltage measurement capability is improved, but magnetizing current causes measurement errors
Solution Approach 1:
The voltage clamp mechanism uses feedback control to sense the magnetizing current in the sampling transformer and apply a compensating voltage that forces the average magnetizing current to zero. This feedback loop eliminates the measurement error caused by magnetizing current while maintaining the transformer's voltage measurement capability.
Solution Approach 2:
The system dynamically adjusts the voltage clamp mechanism's operating parameters to maintain zero average magnetizing current across varying measurement conditions. By changing the clamp voltage parameter in response to operating conditions, the system maintains measurement accuracy without requiring a different transformer for each condition.
2Measurement precision
If voltage clamp mechanism is active during sampling, then magnetizing current is controlled, but switching complexity increases
Solution Approach 1:
The system uses periodic switching of the voltage clamp mechanism synchronized with the sampling clock. The clamp is activated during specific phases of the sampling cycle and deactivated during others, creating a regular periodic pattern that simplifies control logic while maintaining measurement accuracy throughout the cycle.
Solution Approach 2:
The voltage clamp mechanism is activated in advance of the actual voltage sampling operation. This preliminary activation ensures that the magnetizing current is already controlled to zero before the sampling switch closes, eliminating transient errors and simplifying the main sampling switch's control requirements.
3Speed
If sampling frequency is increased to capture voltage variations, then measurement responsiveness is improved, but magnetizing current instability increases
Solution Approach 1:
The voltage clamp mechanism provides real-time feedback control that dynamically adjusts to maintain zero average magnetizing current regardless of sampling frequency. This feedback system responds to changes in operating conditions caused by different sampling rates, ensuring magnetizing current stability is maintained even as responsiveness increases.
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 solution enables precise voltage measurement and control, minimizing errors and maintaining accuracy across varying conditions, thus preventing battery degradation and ensuring optimal operation.
Implementation Method 1
a sampling transformer, a pulse driven switch coupled to the sampling transformer
Implementation Method 2
The voltage clamp mechanism is operable to balance volt-seconds and force an average magnetizing current in the sampling transformer to about zero amperes
Implementation Method 3
The synchronized sampling switch is operable to electrically couple the sampling transformer to a sampling capacitor
Data Source
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AI summary
A system and methods for cell telemetry are disclosed. An average magnetizing current in a sampling transformer is forced to about zero amperes by balancing volt-seconds using a voltage clamp mechanism. Furthermore, a pulse driven switch and a synchronized sampling switch are activated, and substantially simultaneously the voltage clamp mechanism deactivated.