3.3.3 Accumulated Current Quantities
The metrology module generates the following accumulated current (I2) quantities: I_A, I_B, I_C, I_Ni, I_Nm, I_Nmi, I_A_F, I_B_F, I_C_F, and I_Nm_F.
I_x, and I_x_F
These accumulators are in units of [Amp2 samp scaled] in format [uQ24.40] and represent the accumulated scaled current quantities in the integration period. They are calculated according to the following formula:
Where,
- I_x_samplei is ith sampled current value of phase x in the present integration period
- x = [A, B, C]
- N = The number of samples in the last measurement interval
I_Nm, and I_Nm_F are the accumulator for measured neutral current. These accumulators are in units of [Amp2samp scaled] in the uQ24.40 format.
In the case of being multiplexed with temperature measurement acquisition, such as when using the PIC32CXMTC with an external ATSENSE301, slightly less performance may be expected than DSP-filtered full bandwidth data, calculated according to the following formula:
Where,
- I_Nm_samplei is ith sampled measured neutral current value from current input I0 in the last integration period
- N = The number of samples in the last measurement interval
I_Ni, and I_Nmi
These neutral currents are unscaled in units of [Amp2samp] and are computed directly from DSP-filtered baseband current channel data streams. These neutral currents are unscaled (not normalized by the K_Ix current sensor scale factors); therefore, these accumulators are all in units of (Amp2samples) in the uQ44.20 format.
I_Ni is the accumulator for imputed neutral current using full bandwidth (fundamental + harmonics) DSP-filtered baseband current channel data calculated according to the following formulas:
Where,
- I_Ni_samplei is ith sampled imputed neutral current value computed from the sum of all active current phase currents in the present integration period
- N = The number of samples in the last measurement interval
I_Nmi is the accumulator for the difference between the sample-by-sample measured and imputed neutral currents. This integration is sensitive to both magnitude and/or phase differences between the measured and imputed neutral currents, calculated according to the following formula:
Where,
- I_Nm_samplei is ith sampled measured neutral current
- I_Ni_samplei is ith sampled imputed neutral current value computed from the sum of all active current phase inputs in the present integration period
- N = The number of samples in the last measurement interval
| Name: | I_A, I_B, I_C, I_Ni, I_Nm, I_Nmi, I_A_F, I_B_F, I_C_F, I_Nm_F |
| Property: | Read |
| Bit | 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | |
| I_x/I_x_F[63:56] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | |
| I_x/I_x_F[55:48] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | |
| I_x/I_x_F[47:40] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 | |
| I_x/I_x_F[39:32] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| I_x/I_x_F[31:24] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| I_x/I_x_F[23:16] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| I_x/I_x_F[15:8] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| I_x/I_x_F[7:0] | |||||||||
| Access | R | R | R | R | R | R | R | R | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |