Zero Cross Detection Circuit Power Supply System
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for detecting the zero cross point of alternating current voltage consume significant power due to the use of photo couplers, necessitating a more power-efficient solution while maintaining detection reliability.
Innovation Solution
A power supply system that limits the output current of the rectification circuit using capacitors, allowing zero cross point detection without a photo coupler, and incorporates a signal generation circuit to generate detection signals based on the rectification circuit output, along with a reverse voltage applying circuit for noise robustness and a diode for backflow regulation, reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photo coupler is used to detect the zero cross point, then detection reliability is maintained, but power consumption increases due to the photo diode
Solution Approach 1:
The patent extracts and removes the photo coupler component from the detection system. Instead of using optical detection, the invention directly utilizes the rectified current signal from the power supply circuit to detect the zero cross point, eliminating the need for photo diodes and their associated power consumption while maintaining detection functionality
Solution Approach 2:
The patent makes the power supply circuit serve dual functions: both powering the system and providing the detection signal. The rectified current from the power supply's own rectification circuit is used directly for zero cross detection, eliminating the need for separate detection components and reducing overall power consumption
2Use of energy by moving object
If the output current of the rectification circuit is limited by capacitors, then power consumption is reduced, but detection precision may be affected
Solution Approach 1:
The patent changes the electrical parameters of the detection circuit by using capacitor-based current limiting instead of high-current designs. The capacitors C1 and C2 are specifically selected to limit current to a small value suitable for low-power operation while maintaining sufficient signal amplitude for accurate zero cross detection by the transistor Q1
3Device complexity
If a simple circuit configuration is used for zero cross detection, then device complexity is reduced, but noise immunity may deteriorate
Solution Approach 1:
The patent applies preliminary anti-action by using a reverse voltage applying circuit that proactively counteracts potential noise and false triggering. The capacitor C3 and resistor R3 combination applies reverse voltage to the transistor base during critical periods, preventing noise from causing incorrect detection signals while keeping the overall circuit simple
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 approach enables reliable zero cross point detection with reduced power consumption, allowing for early detection after power supply activation and improved precision, while also enabling the system to function as a power supply during power saving modes.
Implementation Method 1
the output of the rectification circuit rectifies the alternating current output of the alternating current power supply
Implementation Method 2
the output current of the rectification circuit is limited to a small value by the first and second capacitors
Implementation Method 3
The backflow regulation element may be a diode
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power supply system includes: a switching power supply generating a voltage from an alternating current power supply; capacitors connected to the alternating current power supply; a rectification circuit configured to rectify an alternating current voltage applied to the capacitors; a backflow regulation regulating backflow of current from the switching power supply; a signal generation circuit generating a detection signal corresponding to a zero cross point of the alternating current power supply; a power supply line connected to the switching power supply and the rectification circuit; an electricity storage unit connected to the power supply line; a voltage limit element configured to limit a voltage of the output line of the rectification circuit, and a control unit, power being fed to the control unit through the power supply line. The control unit is configured to detect a zero cross point based on the detection signal.