Methods, apparatus and articles of manufacture to regulate relay coil switching

An apparatus comprising:

• a relay controllable to selectively and electrically couple an alternating current (AC) power source and a load;
• a sensing circuit to form a digital pulse train representative of an AC signal at the load;
• and
• a computing unit configured to regulate switching times of the relay by:
• determining a first value representative of an average pulse width of the digital pulse train;
• providing a first relay switching signal to the relay at a first time relative to a zero crossing of the AC signal;
• determining a second value representative of the width of a first pulse of the digital pulse train associated with the first relay switching signal at the first time;
• selecting a second time for providing a second relay switching signal to the relay based on a comparison of the first and second values;
• and
• providing the second relay switching signal to the relay at the second time.

A non-transitory tangible article of manufacturing storing machine-readable instructions that, when executed, cause a machine to at least:

• receive from a circuit a digital pulse train representative of an alternating current (AC) signal at a load selectively and electrically coupled to an AC power source via a relay;
• determine a first value representative of an average pulse width of the digital pulse train;
• provide a first relay switching signal to the relay at a first time relative to a zero crossing of the AC signal;
• select a second time for providing a second relay switching signal to the relay based on a comparison of the first value and a second value representative of the width of a first pulse of the digital pulse train associated with the first relay switching signal at the first time;
• and
• provide the second relay switching signal to the relay at the second time.