G - Physics – 01 – R
Patent
G - Physics
01
R
324/70
G01R 21/06 (2006.01) G01R 1/02 (2006.01) G01R 21/00 (2006.01) G01R 21/133 (2006.01)
Patent
CA 1218414
IMPROVED ELECTRONIC WATT/WATTHOUR METER WITH AUTOMATIC ERROR CORRECTION AND HIGH FREQUENCY DIGITAL OUTPUT ABSTRACT OF THE DISCLOSURE An improved solid state semiconductor integrated circuit electronic watt/watthour meter circuit having analog and high frequency digital outputs with automatic error correction. The meter comprises first and second transformers for developing first and second voltage and current indicating signals for supply to a multiplier circuit that multiplies the two signals together and derives an output analog product signal representative of the instantaneous power being supplied by a source of electric energy. The multiplier circuit comprises a comparator for receiving the first voltage indicating signal and a triangular waveshape sampling signal having a much higher frequency than the line frequency of the voltage and current being measured. The comparator derives at its output a pulse width modulating switching signal which controls a multiplier switching circuit having the second current indicating signal supplied thereto as an input and for deriving at its output a pulse width modulating and amplitude modulated product signal representative of the instantaneous power. A multiplier low pass filter circuit is coupled to the output from the multiplier circuit for deriving from the pulse width modulated and amplitude modulated product signal an average value power signal V where V = VI Cos .theta., V is the load voltage, I is the load current and .theta. is the load impedance phase angle. An analog-to-pulse rate converter is supplied the average value power signal V and serves to convert it into a high frequency train of output signal pulses wherein each output signal pulse represents a predetermined quantized amount of electric energy. An automatic offset error correction circuit comprising polarity reversing switches is responsive to Abstract of the Disclosure - Continued the output from the analog-to-pulse rate converter for automatically switching the polarity of the average value power signal V supplied to the analog-to-pulse rate converter midway through the quantizing period of the analog-to-pulse rate converter to cause an up/down integration of the average value power signal V over each quantizing period of operation and simultaneously producing a sequential addition/subtraction of like polarity offset error signals over each quantizing period of operation to thereby cancel out the offset error signals automatically. A watthour indicator is coupled to the output from the analog to pulse rate converter and a watt indicator is coupled to the output from the multiplier low pass filter circuit for deriving respectively indications of the kilowatt hours and watts of energy being supplied by a source of electric energy being measured. The meter can be used with both single phase and polyphase power systems.
450399
Company General Electric
Eckersley Raymond A.
LandOfFree
Electronic watt/watthour meter with automatic error... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronic watt/watthour meter with automatic error..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic watt/watthour meter with automatic error... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1274125