Low-Capacity Power Supply Circuit Zero-Crossing Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting zero-crossing points of AC voltage, such as those using photocouplers, consume significant electric power, necessitating a more power-efficient solution.
Innovation Solution
A power supply system that utilizes the rectified current of a low-capacity power supply circuit to perform zero-crossing detection, employing a pulse generating circuit connected to the current path of the rectifier circuit to generate a pulse signal based on the rectified current, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photocoupler-based zero-crossing detection is used, then zero-crossing detection accuracy is improved, but power consumption increases
Solution Approach 1:
The invention extracts only the necessary function of zero-crossing detection from the rectified current path, using a simple pulse generating circuit instead of a complete photocoupler system. This removes unnecessary power-consuming components while retaining the essential detection capability.
Solution Approach 2:
The rectified current itself is utilized to generate the detection signal through the pulse generating circuit. The system serves itself by using its own operating current for detection purposes, eliminating the need for separate power-consuming detection circuits.
2Use of energy by moving object
If low-capacity power supply circuit is used for zero-crossing detection, then power consumption is reduced, but detection capability must be maintained
Solution Approach 1:
The pulse generating circuit acts as an intermediary that converts the rectified current into detectable pulse signals. This mediator enables reliable zero-crossing detection while operating within the low-power constraints of the low-capacity power supply circuit.
Solution Approach 2:
The invention changes the operational parameters by using the existing rectified current waveform directly for detection purposes, rather than requiring additional power supply capacity. The pulse generating circuit is designed to operate effectively with the available low-power rectified current.
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 allows for effective zero-crossing detection while significantly reducing electric power consumption, achieving a power savings of about 80 µW compared to traditional methods.
Implementation Method 1
a rectifier circuit (31) and a pulse generating circuit (34). The pulse generating circuit (34) is connected to a current path (IP) of the rectifier circuit (31)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power supply system comprises: a switching power supply for generating a DC voltage by rectifying and smoothing an AC voltage of an AC power supply; a control device switching the switching power supply between the normal mode and a power saving mode; and a low-capacity power supply circuit supplying electric power to the control device in the power saving mode. The low-capacity power supply circuit includes: two capacitors, each including one end connected to the AC power supply; a rectifier circuit that is electrically connected between the other ends of the capacitors, and rectifies the AC voltage applied between the first and second capacitors; and a zero-crossing detecting circuit that is connected to a current path at the rear stage of the rectifier circuit, and detects zero-crossing points of the AC power supply.