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Direct Current in the home

PeterRT

With more and more in the home being powered off DC (Direct Current) supplies, e.g. Battery & Solar Panels, then wouldn't it be more economical to consider extending the regulations to cover DC in the home avoiding the need for transformers?

For example, this is particularly appropriate now that lighting is dominated by LED.

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    SMPS are certainly lighter weight and more efficient than a conventional transformer plus linear regulator combo, as well as being more forgiving of mains variations - the mark-space ratio of the ultrasonic chopping waveform can be varied to alter the transformation ratio - by the same mechanism they can be made to draw current at intermediate voltages up and down the sides of a sinewave - while a 50Hz rectifier into a smoothing cap only draws current in a short burst near the crests when the input exceeds the reservoir, so with a bit of careful control, it is also possible to improve power factor/waveform quality this way. 

    However, they are not really more efficient than a well designed 50Hz transformer driving a resistive load like a lamp filament, so long as you are not trying to regulate. (magnetizing current is not loss, as it is at 90 degrees to the voltage.) Even so the fact that it is smaller and lighter and cheaper to make, usually wins the day.

    Mike

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  • 0

    SMPS are certainly lighter weight and more efficient than a conventional transformer plus linear regulator combo, as well as being more forgiving of mains variations - the mark-space ratio of the ultrasonic chopping waveform can be varied to alter the transformation ratio - by the same mechanism they can be made to draw current at intermediate voltages up and down the sides of a sinewave - while a 50Hz rectifier into a smoothing cap only draws current in a short burst near the crests when the input exceeds the reservoir, so with a bit of careful control, it is also possible to improve power factor/waveform quality this way. 

    However, they are not really more efficient than a well designed 50Hz transformer driving a resistive load like a lamp filament, so long as you are not trying to regulate. (magnetizing current is not loss, as it is at 90 degrees to the voltage.) Even so the fact that it is smaller and lighter and cheaper to make, usually wins the day.

    Mike

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