Zero-Crossing Detection Circuit With Interval-Limited Optocoupler Drive
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Solution Overview
Problem
Existing zero-crossing detection circuits consume excessive power due to large energy storage capacitors and prolonged charging times, which affects detection accuracy and component lifespan.
Innovation Solution
A zero-crossing detection circuit design featuring a photoelectric coupler, optocoupler driving module, and energy storage capacitor with current-limiting resistors and voltage clamp modules, reducing conduction intervals and power consumption while maintaining high detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a large capacitance energy storage capacitor is used to control optocoupler conduction, then the optocoupler can maintain conduction state, but the charging time increases and power consumption increases
Solution Approach 1:
The patent implements periodic action by controlling the optocoupler to conduct only during specific intervals when zero-crossing detection is needed, rather than maintaining continuous conduction. The control signal activates the optocoupler periodically synchronized with the AC waveform, reducing power consumption while ensuring detection accuracy at critical moments.
Solution Approach 2:
The patent applies dynamics by making the optocoupler conduction state dynamic rather than static. The conduction duration and timing are adjusted dynamically based on the AC signal phase and zero-crossing detection requirements, allowing the system to optimize between maintaining sufficient conduction for detection and minimizing power consumption during non-critical periods.
2Duration of action of stationary object
If a large capacitance energy storage capacitor is used, then the optocoupler conduction is maintained, but the charging time increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the energy storage capacitor during periods when power is available and zero-crossing detection is not critical. The capacitor is charged in advance during normal operating cycles, so that when zero-crossing detection is needed, the capacitor is already charged and ready to provide immediate conduction without delay.
3Use of energy by stationary object
If the photoelectric coupler conduction interval is reduced, then power consumption decreases and component lifespan increases, but detection accuracy may be compromised
Solution Approach 1:
The patent applies local quality by concentrating the optocoupler conduction activity precisely at the local moment when zero-crossing detection is critical, rather than distributing conduction uniformly over time. The control system identifies the specific timing when detection accuracy is most important and ensures optocoupler conduction is active only during those critical local intervals, optimizing both power efficiency and detection precision.
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 circuit achieves power-saving and prolongs component lifespan by minimizing the ON duration of the photoelectric coupler, ensuring high accuracy and efficiency in zero-crossing detection.
Implementation Method 1
a photoelectric coupler, connected to the zero-crossing judgment module
Implementation Method 2
an energy storage capacitor, wherein the energy storage capacitor is configured to provide excitation power for the photoelectric coupler and the optocoupler driving module
Data Source
AI summary
The present disclosure discloses a zero-crossing detection circuit, including: a zero-crossing judgment module, having a first end and a second end, wherein the first end is connected to a power supply and the second end is grounded; a photoelectric coupler, connected to the zero-crossing judgment module; an optocoupler driving module, connected to the photoelectric coupler; and an energy storage capacitor, wherein the energy storage capacitor is configured to provide excitation power for the photoelectric coupler and the optocoupler driving module.