Abstract: Described are methods, devices and systems for communicating data measurements from a sampling device to a remote master device in a distributed power measurement system using high-speed isochronous data links. The sampling device receives a time-stamp packet from the master device over the isochronous data link, the time-stamp packet containing a sequence number of the time-stamp packet, and the sampling device starts a counter clocked by a local clock signal to determine an offset time since receipt of the time-stamp packet. The sampling device obtains power system data and generates and transmits framed output data to the remote master device over the isochronous data link. The framed output data includes the sequence number, the offset time, and a data payload that includes the power system data.

Abstract: A power measurement device for sampling current or voltage signals of a power system to produce a 1-bit delta-sigma bitstream. The power measurement device includes a frequency locked loop for determining the power system frequency directly from the 1-bit delta-sigma bitstream. The frequency locked loop includes a 1-bit rotate CORDIC that is configured to produce difference signals having a multi-bit word for each bit of the 1-bit delta-sigma bitstream, and a phase error calculator that determines the difference between the phase of the power system frequency and a phase ramp generated from a frequency measurement value in a frequency register. The phase error calculator feeds back a phase correction signal to the frequency register to lock the frequency measurement value to the power system frequency.

Abstract: Described are methods, devices and systems for communicating data measurements from a sampling device to a remote master device in a distributed power measurement system using high-speed isochronous data links. The sampling device receives a time-stamp packet from the master device over the isochronous data link, the time-stamp packet containing a sequence number of the time-stamp packet, and the sampling device starts a counter clocked by a local clock signal to determine an offset time since receipt of the time-stamp packet. The sampling device obtains power system data and generates and transmits framed output data to the remote master device over the isochronous data link. The framed output data includes the sequence number, the offset time, and a data payload that includes the power system data.

Abstract: Described is a method and devices to determine root-mean-square of a delta- sigma modulated signal. The method includes filtering the delta-sigma modulated signal to produce a multi-bit filtered signal, delaying a copy of the delta-sigma modulated signal by a fixed number of samples to align with the filtered input, setting a sign of each multi-bit value of the multi-bit filtered signal based upon a corresponding sample value of the delayed copy of the delta-sigma modulated signal, to generate a hybrid signal, summing the hybrid signal to produce a summed signal, and determining the average of the summed signal and the square root of the average to produce a root-mean-square value.

Abstract: A power measurement device for sampling current or voltage signals of a power system to produce a 1-bit delta-sigma bitstream. The power measurement device includes a frequency locked loop for determining the power system frequency directly from the 1-bit delta-sigma bitstream. The frequency locked loop includes a 1-bit rotate CORDIC that is configured to produce difference signals having a multi-bit word for each bit of the 1-bit delta-sigma bitstream, and a phase error calculator that determines the difference between the phase of the power system frequency and a phase ramp generated from a frequency measurement value in a frequency register. The phase error calculator feeds back a phase correction signal to the frequency register to lock the frequency measurement value to the power system frequency.