Alternator Acquisition Circuit Phase Detection
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Solution Overview
Problem
Conventional alternator control systems in automotive systems face challenges in accurately controlling excitation current and output voltage, particularly during engine startup and low-speed conditions, due to the limitations of on-chip phase signal detection, which results in low accuracy and high reaction times.
Innovation Solution
An acquisition circuit that utilizes capacitive coupling with a high-ohmic resistive element to derive validation signals from alternator output signals, allowing for precise phase information extraction and frequency determination, enabling efficient control of excitation current and output voltage, even with small capacitors suitable for integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If on-chip phase signal detection is used, then cost is reduced and integration is improved, but measurement precision and reaction time deteriorate
Solution Approach 1:
The patent introduces a coupling circuit as an intermediary between the alternator output and the detection circuit. This coupling circuit includes a capacitive element and a resistive element that work together to condition the phase signal, enabling accurate detection while maintaining on-chip integration. The intermediary circuit transforms the raw alternator output into a form suitable for precise measurement without requiring external sensors.
2Device complexity
If conventional detection circuits are used, then device complexity is reduced, but measurement precision and control speed worsen
Solution Approach 1:
The detection function is segmented into multiple specialized circuits: a coupling circuit for signal conditioning, a detection circuit for phase signal acquisition, and a validation circuit for signal verification. This segmentation allows each circuit to be optimized for its specific function, achieving high measurement precision and fast response while keeping individual circuit blocks relatively simple and suitable for on-chip implementation.
3Measurement precision
If high-ohmic resistance is used in coupling, then input resistance increases and signal accuracy improves, but susceptibility to noise increases
Solution Approach 1:
The patent implements a validation circuit that provides feedback verification of the detected phase signal. The validation circuit checks whether the detected signal meets predetermined criteria before accepting it as valid. This feedback mechanism allows the system to use high-ohmic resistance for accurate signal detection while compensating for noise susceptibility by verifying signal validity and rejecting invalid readings.
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 achieves accurate and timely control of alternator excitation current and output voltage, overcoming the limitations of conventional systems by using capacitive coupling and high-ohmic resistance to set an operational point independently of the signal source, while maintaining a high input resistance and suppressing uncorrelated disturbances.
Implementation Method 1
the circuit for coupling having a capacitive element for coupling the alternator output signal and the coupling signal
Implementation Method 2
the circuit for coupling further having a resistive element for coupling the coupling signal and a reference signal
Data Source
AI summary
An acquisition circuit for providing a first and a second validation signal based on an alternator output signal has a coupler being adapted for receiving the alternator output signal and for providing a coupling signal having information on the phase of the alternator output signal, the coupler having a capacitive element for coupling the alternator output signal and the coupling signal, the coupler having a resistive element for coupling the coupling signal and a reference signal. The acquisition circuit further has a detector adapted for receiving the coupling signal and for providing the first and second validation signals, wherein the relation between the validation signals is based on the information on the phase of the output signal, wherein the frequency of the alternator output signal is derivable from the validation signals and the validity information is derivable from the relation between the validation signals.