Hold-open Coil Current Regulation via PWM Feedback
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Solution Overview
Problem
Existing parking systems for doors and windows are prone to coil overload or underperformance when operated with supply voltages outside the nominal range, leading to potential damage or failure.
Innovation Solution
An electronic control device that regulates the current flowing through the coil, ensuring it maintains a specified value regardless of the supply voltage, using a measurement resistor and pulse-width modulation to achieve stable operation across a wide voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the supply voltage is increased to improve the holding torque, then the holding capability is enhanced, but the coil may be overloaded and burn out
Solution Approach 1:
The patent implements a feedback control system where a measuring resistor detects the actual current flowing through the coil, and the electronic control unit compares this measured value with a target current value. Based on this feedback, the control unit adjusts the duty cycle of the pulse-width modulated signal to maintain the current at the desired level, preventing overload while ensuring sufficient holding torque.
Solution Approach 2:
The patent uses pulse-width modulation (PWM) to dynamically control the average current through the coil by adjusting the duty cycle. This allows the system to adapt the holding torque to match the actual load requirements while maintaining a safe current limit, rather than applying a fixed high voltage that could cause overload.
2Use of energy by moving object
If the supply voltage is decreased to reduce power consumption, then energy efficiency improves, but the hold-open device may not provide sufficient release torque
Solution Approach 1:
The patent uses pulse-width modulation to dynamically control the average power consumption while maintaining sufficient peak current for release torque. By adjusting the duty cycle, the system can operate at lower average power levels while still delivering the necessary current pulses to generate adequate release torque when needed.
Solution Approach 2:
The patent changes the operational parameters by using current-controlled PWM instead of direct voltage application. This allows the system to maintain the coil current within an optimal range that provides sufficient release torque while consuming less power, especially during the hold-open phase where continuous high current is not needed.
3Adaptability or versatility
If the supply voltage varies in the building network, then adaptability to different networks improves, but the coil current becomes unstable and performance degrades
Solution Approach 1:
The patent employs a feedback control system that continuously monitors the actual coil current and adjusts the PWM duty cycle to maintain a stable target current value regardless of supply voltage variations. This feedback mechanism compensates for voltage fluctuations and ensures consistent holding and release performance across different voltage conditions.
Solution Approach 2:
The patent uses electronic control to dynamically adjust the effective current through the coil by modifying the PWM duty cycle in response to supply voltage changes. This allows the system to maintain stable coil current and consistent performance parameters even when the supply voltage varies across different building networks.
4Device complexity
If conventional hold-open devices are designed for a defined supply voltage, then the device complexity is reduced, but the device cannot operate reliably with varying supply voltages
Solution Approach 1:
The patent implements a feedback control system with current detection using a measuring resistor and electronic control that regulates coil current based on PWM duty cycle adjustment. This relatively simple feedback mechanism enables the device to operate reliably across a wide voltage range (12V DC to 48V DC) without requiring complex voltage detection or multiple operating circuits.
Solution Approach 2:
The patent designs the hold-open device with a universal control architecture that can operate with different supply voltages (12V DC, 24V DC, 48V DC) using the same basic circuitry. The electronic control unit and PWM regulation system provide multi-functionality, allowing the device to adapt to various voltage conditions without requiring voltage-specific design variations.
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 system ensures reliable operation of the parking system across a wide range of supply voltages (e.g., 12V DC to 48V DC) by maintaining a constant current through the coil, preventing coil overload and ensuring consistent performance.
Implementation Method 1
an energizable coil (13) which, when energized, is designed to block automatic closing of the wing by a drive connected to the wing
Implementation Method 2
a measuring resistor, in particular one connected in series with the coil, can be provided, and the electronic control unit can be configured to detect the current flowing through the coil by means of the measuring resistor
Implementation Method 3
the electronic control unit is configured to control the electronic switching element with a pulse-width modulated signal having a duty cycle and to regulate the current flowing through the coil to the predetermined value by adjusting the duty cycle of the pulse-width modulated signal
Data Source
Figure 1
AI summary
The invention relates to a hold-open device for holding an open sash of a door, window, or the like, comprising an energized coil designed to block automatic closing of the sash by a drive connected to the sash when energized, a supply voltage input for the coil, and an electronic control unit. The electronic control unit is configured to energize the coil upon activation and subsequently regulate the current flowing through the coil to a predetermined value, whereby the current flowing through the coil is measured for current regulation.