Multi-functional Energy Metering IC

Transcription

1 The World Leader in High Performance Signal Processing Solutions Multi-functional Energy Metering IC ADE7753 (Single Phase)

2 A programmable solution for Energy measurement Transducers Current Voltage ADE7753 ADC + Fixed functions DSP Energy Measurements Simple Signal Processing & Communication MCU LCD Display Circuit Breaker Infrared Interface User interface Billing information & Meter control command Power Line Carrier Short-range RF GSM cellular network Data Communication or Automatic Meter Reading (AMR) April-2003 Page 2 of 18

3 Technology at a glance High Resolution Data Conversion Fixed Function DSP D.C. to 5KHz D.C. to 5KHz bit bit ADC bit bit ADC Multiply & LPF On On chip chip Temp. Temp. sensor sensor Digital-To- Frequency Serial Port Interface A proven analog front end from AD7755 Superior DSP Performance April-2003 Page 3 of 18

4 Single Chip Energy Meter Lowest Cost Single Phase Measurement Single 5V Power Supply Connect directly to current sensor Connect directly to voltage sensor AD7751 or AD7755 (Sensor Interface & Calculation IC) Frequency out (Kilowatt-hours) Quality brochure available: April-2003 Page 4 of 18

5 Overview of Functionalities Surpasses IEC1036 requirement. Less than 0.1% error over a large current dynamic range Supplies the following information: kw, kwhr kv, kvarhr VA RMS Voltage and Current Peak Voltage and Current SAG detection Line Period Temperature Digital calibration April-2003 Page 5 of 18

6 Block Diagram Analog Front end Current sensor Digital solution Active Energy Calibration Mode RMS measurements Apparent Energy Reactive Energy Power Line Quality Temperature sensor Accumulation Modes April-2003 Page 6 of 18

7 A validated Analog front end 16-bit accuracy from 2nd order SD ADC Linearity error < 0.1% over 1:1000 dynamic range (int. reference) Measurement Bandwidth 14 khz April-2003 Page 7 of 18

8 Easy use of Current sensors On-chip digital integrator in the current channel enables direct interface to di/dt sensor (Rogowski coil) Input Gain up to 64 to interface low shunt resistor Gain of 16 recommended for 100mW Phase compensation for CT ~ to max in Hz April-2003 Page 8 of 18

9 A Digital solution No manual calibration Configuration done by writing ADE7753 registers at power up 0.1% accuracy 1000:1 CF output to drive LED April-2003 Page 9 of 18

10 Voltage and Current RMS, and waveform samples Voltage and Current RMS values in 24-bit registers Offsets compensate RMS noise integration and improve accuracy Real-time voltage and current waveforms can be supplied in four different sampling speed (up to 28ksps) April-2003 Page 10 of 18

11 Active Energy Accumulation of the Active Energy in a 24-bit register Equivalent to 3.12min of Energy at Full scale HPF filter eliminates any DC offset Gain for calibration and multi-rate billing (WGAIN and WDIV) April-2003 Page 11 of 18

12 Apparent Energy (VA) is calculated using: VA = Vrms x Irms Accumulation of the Apparent Energy in a 24-bit register Gain for calibration and multi-rate billing (VAGAIN and VADIV) April-2003 Page 12 of 18

13 Active and Apparent Energy Principle: Accumulation of the Active and Apparent Energy over N half line cycles (<16384) Drive IRQ when finished Benefits: Cancel the ripple frequency effect (2 x line freq) in Energy Measurement Shorten calibration time ENERGY Instantaneous Power Line Voltage (CH2) Sampling time of Energy measurement in Calibration mode Average Power t t April-2003 Page 13 of 18

14 Reactive Energy (VAR) - 1 can be directly read from the LVARENERGY[23:0] The sign of LVARENERGY indicates inductive or capacitive loading kvarhr is updated synchronous to a programmable number of voltage half-cycles to improve accuracy April-2003 Page 14 of 18

15 Reactive Energy (VAR) - 2 Proposed Method to measure Reactive Energy and Power Factor accurately: Using synchronous VA and kwhr data kvarhr = (VA kwhr 2 ) = (LVAENERGY - LAENERGY 2 ) PF = sign(lvarenergy) * LAENERGY/ LVAENERGY The nature of the load (inductive or capacitive) is determined by the sign of LVARENERGY register April-2003 Page 15 of 18

16 Power Line Quality Supervisory Period Measurement of the Voltage channel Configurable SAG and Peak detections of the Voltage channel Actual peak values of Current and Voltage channels available Zero crossing of the Voltage channel Peak Level SAG Level Voltage Channel Peak detection SAG detection Zero crossing time out detection t Zero crossing detection Line Period April-2003 Page 16 of 18

17 Temperature Measurement 8-bit register : 1LSB/ C Temperature compensation of external components Temperature supervisory of the system April-2003 Page 17 of 18

18 Energy Accumulation Features Positive Only Accumulation Mode optional Selectable Mode to accumulate positive active power only or arithmetic accumulation of power UK requirement No Load Threshold built in feature No accumulation below 0.001% of Full Scale Active Power eliminates creep Active Energy Register No-load threshold Active Power No-load threshold April-2003 Page 18 of 18