Zero-crossing detection device and method thereof and no-neutral switch

A no-neutral switch, comprising:

• a zero-crossing detection device;
• and
• a switch element connected with the zero-crossing detection device, having a first end connected to a power supply and a second end connected to a load, configured to adjust power provided to the load from the power supply according to the zero-crossing point provided by the zero-crossing detection device;
• wherein the zero-crossing detection device comprises:
• a computing module;
• a sampling module configured to sample a first signal of the first end of the switch element and a second signal of the second end of the switch element;
• and
• a comparison module configured to compare a deviation of the first signal and the second signal with a preset threshold and to send a triggering signal to the computing module when the deviation exceeds the preset threshold;
• wherein the computing module is configured to compute a zero-crossing point of the power supply according to time of the triggering signal and time delay of the triggering signal relative to the zero-crossing point according to frequency of the power supply and the preset threshold.

A method of detecting a zero-crossing point of a power supply for a no-neutral switch, wherein the no-neutral switch comprises a switch element, the switch element has a first end connected to the power supply and a second end connected to a load, wherein the method comprises:

• sampling a first signal of the first end of the switch element and a second signal of the second end of the switch element;
• comparing a deviation of the first signal and the second signal with a preset threshold that comprises when the deviation exceeds the preset threshold, sending a triggering signal;
• and
• computing the zero-crossing point of the power supply according to time of the triggering signal and time delay of the triggering signal relative to the zero-crossing point and computing the time delay according to frequency of the power supply and the preset threshold.