Safety Power Window Ripple Current Detection
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Solution Overview
Problem
Four-pole stator motors in safety power window systems generate irregular ripples, leading to missed pulses due to brushes arranged at 90-degree intervals, which complicates the detection of desired pulse waveforms and disrupts the automatic window control mechanism.
Innovation Solution
A safety power window controlling apparatus that includes a ripple current detector to remove high-frequency noise from the motor's output current, an amplifier to amplify the ripple current, and a valid signal detector using two reference values to stabilize pulse detection, ensuring reliable pulse signal generation even with irregular ripples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a four-pole stator motor is used, then the motor provides sufficient power for window operation, but irregular ripples are generated causing pulse detection failures
Solution Approach 1:
The patent changes the detection parameters by using multiple reference values (first reference value based on maximum current, second reference value based on average current) instead of a single threshold. This allows the system to adapt to the irregular ripple characteristics of four-pole motors while maintaining reliable pulse detection.
Solution Approach 2:
The patent introduces an intermediary processing stage between the motor and the detection system, including a ripple current detector to extract ripple components and an amplifier to enhance the signal. This intermediary processing enables reliable detection despite the irregular ripple patterns generated by four-pole motors.
2Device complexity
If brushes are arranged at 90-degree intervals in a four-pole motor, then the motor structure is simplified, but regular pulse waveforms cannot be generated
Solution Approach 1:
The patent replaces the mechanical expectation of regular pulse generation from brush arrangement with an electronic detection system. Instead of relying on the mechanical structure to produce regular pulses, the system uses electronic signal processing (ripple detection, amplification, and multi-reference comparison) to identify motor rotation pulses, thereby decoupling pulse regularity from brush arrangement.
Solution Approach 2:
The patent introduces dynamic adaptation in the detection system by using multiple reference values that can accommodate variations in ripple patterns. The system dynamically adjusts its detection criteria based on the actual ripple characteristics, allowing it to handle the irregular pulse waveforms produced by the simplified 90-degree brush arrangement.
3Device complexity
If a single reference value is used for pulse detection, then the detection system is simple, but pulses are missed due to irregular ripples
Solution Approach 1:
The patent segments the reference system into multiple independent reference values: a first reference value derived from the maximum current and a second reference value derived from the average current. This segmentation allows each reference to handle different aspects of the irregular ripple signal, improving detection accuracy without creating a monolithic complex system.
Solution Approach 2:
The patent uses excessive action by employing more reference values than the minimum single threshold. This over-determination approach ensures that even with irregular ripples, at least one reference condition will be satisfied for valid pulse detection, thereby improving reliability at the cost of increased system complexity.
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 effectively prevents pulse missing and stabilizes pulse detection, enabling accurate control of the window glass movement by calculating the motor's revolutions and adjusting the driving direction accordingly, ensuring reliable automatic window operation.
Implementation Method 1
a ripple current detector configured to detect a ripple current by removing high-frequency noise from an output current signal of a four-pole stator motor
Implementation Method 2
an amplifier configured to receive a ripple current as a first input signal, receive a reference voltage as a second input signal, and output an amplified current signal obtained by amplifying the first input signal to a level of the reference voltage
Implementation Method 3
a four-pole stator motor
Data Source
AI summary
Provided is a safety power window controlling method including an operation in which a ripple current detector detects a ripple current by removing high-frequency noise from an output current signal of a four-pole stator motor; an operation in which an amplifier receives a ripple current as a first input signal, receives a reference voltage as a second input signal, and outputs an amplified current signal obtained by amplifying the first input signal to a level of the reference voltage; and detecting the amplified current signal output by the amplifier as a valid signal by using at least two preset reference values.