Isolated Battery Management Circuitry for High Voltage Noise Mitigation
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Solution Overview
Problem
Conventional battery management systems face issues such as high voltage risks, grounding interference, noise from sensing circuits, and false positives in hipot tests due to lack of isolation, which affect reliability and safety.
Innovation Solution
The system employs multiple isolation circuits to separate high voltage from the processor and sensing signals, allowing for grounded or ungrounded inverter power, reducing noise, and improving hipot test consistency through step-down converters and signal conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional battery management systems use non-isolated sensor circuits and processors connected to high voltage, then device complexity is reduced, but voltage risks and noise interference increase
Solution Approach 1:
The system divides the battery management architecture into isolated high-voltage domain and low-voltage domain, with separate processor units (HV-MCU and LV-MCU) handling different functions. The HV-MCU handles high-voltage switching and protection, while the LV-MCU handles communication and control, reducing cross-domain interference and improving reliability.
Solution Approach 2:
Isolation circuits serve as intermediary components between high-voltage and low-voltage domains, including isolated DC-DC converters for power isolation and isolated CAN transceivers for communication isolation. These intermediaries prevent voltage risks and noise from propagating across domain boundaries.
2Measurement precision
If sensing circuits are connected to high voltage without isolation, then device complexity is minimized, but noise interference and measurement precision deteriorate
Solution Approach 1:
Sensing circuits are segmented into high-voltage sensing domain and low-voltage processing domain. High-voltage sensors (current shunts, voltage dividers) are placed in the HV domain with their own isolated ADC and processing unit (HV-MCU), preventing noise coupling into low-voltage communication and control circuits.
Solution Approach 2:
Isolated signal conditioning circuits and isolated CAN transceivers act as intermediaries between high-voltage sensing signals and low-voltage communication interfaces, filtering and conditioning signals while maintaining galvanic isolation to preserve measurement precision.
3Reliability
If grounding paths are tied to chassis in conventional systems, then ease of operation is improved, but grounding interference and hipot test failures increase
Solution Approach 1:
The grounding system is segmented into separate grounding domains for high-voltage and low-voltage circuits. Each domain has its own grounding path and reference potential, preventing ground loops and grounding interference from affecting system operation or causing hipot test failures.
Solution Approach 2:
Isolation circuits with floating grounds serve as intermediaries that break direct grounding paths between high-voltage and low-voltage domains, eliminating grounding interference while maintaining proper reference potentials for each domain independently.
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 design enhances reliability, reduces noise interference, increases debugging efficiency, and improves the consistency of hipot tests, ensuring safer and more reliable battery management.
Implementation Method 1
a first circuit that converts a first voltage from a first level to a lower second voltage
Implementation Method 2
a second circuit that converts the second voltage to a lower third voltage
Implementation Method 3
a third circuit that conditions a battery signal to form a conditioned battery signal
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Systems (100) and method (700) of the invention relate to circuitry (106, 108, 112, 114, 118, 120) that isolates low power circuitry of a battery management system (101). One or more circuits (106, 108, 112, 114, 118, 120) can be utilized with a battery management system (101) to provide isolation of isolates low power circuitry of a battery management system (101) from at least one of a high voltage, noise interference from a battery module (102), noise interference from a high voltage, sensor signals, control signals, among others. The circuitry (106, 108, 112, 114, 118, 120) further provides high voltage from a grid to be stepped-down to a voltage level usable by circuitry, port(s), and/or a processor (116).