1、SA9904B
SA9904B has 20 pins, PDIP package and 12 meta registers. SA9904B contains nine 24-bit registers, which respectively represent the active energy, reactive energy and power supply voltage of each phase.
The 65438th+00th 24-bit register represents the local frequency of any valid phase, including three addresses to maintain compatibility with SA9604A. Any of the three addresses can be used to access the frequency register. The active and reactive power of each phase is stored in a 24-bit register.
2、ATT7026A
ATT7026A has 44 pins, QFP44 package and 102 register flip. Active power is obtained by calculating the algebraic average of instantaneous power. The active power of split-phase and combined-phase is stored in the specified register for users to read.
The reactive power can be obtained by shifting the voltage sampling signal by 90 degrees and then calculating the algebraic average of instantaneous power. It also provides users with split-phase and combined-phase reactive power.
3、CS5463
CS5463 has 24 pins, SSOP package and 32 registers. The digital quantities of transient voltage and current are obtained by sampling, and the sampling value of instantaneous active power is obtained by multiplying the data of each pair of transient voltage and current.
After each A/ D sampling period, new instantaneous power samples are stored in the power register, and n instantaneous power samples are grouped. The accumulated values of each group are used to calculate the value to be put into the energy register later, which is proportional to the active power value of the circuit in n analog-to-digital conversion cycles.
Extended data
Working principle of electric energy metering chip
Two analog-to-digital converters (ADC) digitize voltage signals from current and voltage sensors. Both ADCs are 16-bit second-order σ -δ analog-to-digital converters with an oversampling rate of 900kHz.
The analog input structure of ADE7755 has a wide dynamic range, which greatly simplifies the design of sensor interface (which can be directly connected to the sensor) and anti-aliasing filter.
The programmable amplifier (PGA) in the current channel further simplifies the sensor interface. The high-pass filter (HPF) in the current channel will filter out the DC component in the current signal, thus eliminating the calculation error of active power caused by voltage or current offset.