Active Filter for High-Voltage Powertrain Interference
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Solution Overview
Problem
Existing interference signal rejection devices for high-voltage powertrains in vehicles are large, expensive, and inefficient, particularly at higher voltages, and struggle to effectively reject interference signals without requiring significant modifications to existing systems.
Innovation Solution
A device with an amplifier circuit that taps interference signals symmetrically from both positive and negative power lines, using an inductor to increase impedance and feed correction signals back into the power lines with reverse polarity, allowing for efficient rejection of interference signals without the need for extensive system modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive components are used for interference signal rejection in high-voltage powertrains, then interference rejection is achieved, but the device becomes large, expensive, and complex
Solution Approach 1:
The patent replaces passive mechanical/electrical filter components with an active electronic system consisting of an amplifier circuit that detects interference signals and generates compensating correction signals. This substitution of passive filtering with active signal processing reduces device complexity while maintaining interference rejection effectiveness at high voltages
Solution Approach 2:
The invention changes the operating parameters by using an amplifier circuit that can operate at lower voltage levels than the power line, enabled by electrical isolation. This allows the use of smaller, less expensive components while still effectively rejecting high-voltage interference signals through proportional correction
2Reliability
If existing power lines are modified to reject interference signals, then interference rejection improves, but system complexity and retrofitting difficulty increase
Solution Approach 1:
The patent extracts the interference rejection function from the power line structure itself and implements it as a separate, self-contained amplifier circuit that taps into the existing power lines. This extraction allows the device to be retrofitted without modifying the existing power line infrastructure, simplifying installation and manufacturing
Solution Approach 2:
The amplifier circuit is designed to work with existing bipolar voltage sources and power line configurations without requiring system-specific modifications. The electrical isolation and symmetrical connection design enable universal application across different high-voltage powertrain systems, facilitating easier manufacturing and retrofitting
3Ease of operation
If the amplifier operates at the same high voltage level as the power line, then direct coupling is achieved, but component requirements and safety constraints increase
Solution Approach 1:
The patent introduces electrical isolation as an intermediary between the amplifier circuit and the high-voltage power line. This isolation enables the amplifier to operate at lower, safer voltage levels while still effectively detecting and correcting high-voltage interference signals through the isolated measurement and correction paths
Solution Approach 2:
The invention separates the voltage dimensions by allowing the amplifier to operate at a different voltage level than the power line it serves. The electrical isolation creates independent voltage domains, enabling the low-voltage amplifier to effectively control and correct high-voltage interference without direct high-voltage coupling
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
The solution provides effective interference signal rejection at high voltages with reduced space and cost requirements, minimizing EMC issues and simplifying retrofitting by operating at a lower voltage level and using discrete semiconductors for faster signal processing.
Implementation Method 1
The inductor represents an increased inductance and prevents the fed-in correction signal from being loaded by a small impedance of the current source
Implementation Method 2
The electrical isolation between the amplifier and the power line in the tapping of the interference signal as well as in the coupling in of the correction signal makes it possible for the amplifier to be operated at a lower voltage level than the power line to be filtered
Data Source
AI summary
The invention relates to a device for rejecting interference signals in bipolar voltage sources, in particular in high-voltage sources in a powertrain of an electric vehicle, wherein an amplifier circuit is provided, with an input stage the input of which is symmetrically connected by means of an electrically isolated tap to a positive power line and a negative power line of a voltage source in order to tap an interference signal, and with an output stage, actuated by the input stage, the output of which is symmetrically connected in each case via an output capacitor to the positive power line and the negative power line, in order to feed in a correction signal.