As a result of increasing law regulations, energy subscribers will be provided more freedom to choose between tariffs and utilities, optimizing their energy costs. However, with an increase in renewable energy generation, local utilities require a more efficient way to monitor the energy consumed on a subscriber level, to adjust the conventional electrical energy generation. The utility’s business model – pre-paid vs. after-paid – will mainly be driven by local consumption and payment habits. Consequently, future electricity meters will require reliable bidirectional communication paths to address these needs. The solutions that will be chosen will depend on local circumstances and will be either wired or wireless. Although the solution presented will address a 3-ph shunt E-Meter application, the same principles of operation are applicable to current transformer and Rogowski-coil based sensing approaches, with the intrinsic isolation provided by the inductive approach being the differentiator as compared to the shunt approach.

System Benefits:

  • The calculated energy parameters will be digitized and transferred via UART to the application's controller through an optical isolator.
  • The digitized metrology data transferred through the optical isolator reaches the applications controller, an Arm® Cortex®-M4 device with 512kB flash and 256kB RAM.
  • The suggested LED and RS-485 interfaces address the capability of bidirectional serial connectivity in production and out in the field.
  • For remote rural deployments with poor grid quality, 2G or 5G wireless connectivity is a must.
  • The suggested mechanical switch is a common approach to detect tamper approaches, triggering a register flag upon case opening.
  • For urban deployments, either Sub-1-GHz communication via a data logger or wired connectivity via power line communication (PLC) is a must; while the RAA6045S00 supports a proprietary frequency-shift keying (FSK) or the Wi-SUN protocol, the R9A06G037 supports the 3G-PLC and PRIME specification.
  • The suggested two DC/DC bucks independently provide the power to the wireless module as well as the application part of the meter; on the other hand, the three LDOs independently supply the power for each metrology phase.
  • Provided the RS-485 interface requires its own galvanic isolation, the same LDO could be optionally used for the case of an existing additional flyback output.



Winning Combinations Interactive Diagram

Select a block to discover products for your design

4:3 ratio Sheet.1 Sheet.2 Sheet.3 Sheet.4 EU019 EU019 EU019 Sheet.54 Sheet.55 Sheet.56 Sheet.57 Sheet.58 Sheet.59 Sheet.60 Sheet.61 Sheet.62 Sheet.63 Sheet.64 Sheet.65 Sheet.66 Sheet.67 Sheet.68 Sheet.69 Sheet.70 Sheet.71 Connector 1.155 Connector 1.155.73 Connector 1.155.74 Connector 1.155.75 Connector 1.155.76 Connector 1.155.77 Connector 1.155.78 Connector 1.155.79 Sheet.80 Connector 1.155.81 Sheet.82 Sheet.83 Sheet.84 Sheet.85 Sheet.86 Sheet.89 Sheet.90 Sheet.91 Sheet.94 Sheet.95 Sheet.96 Sheet.97 Sheet.98 Sheet.99 Sheet.100 Sheet.101 Sheet.102 Sheet.103 Sheet.104 Neutral Neutral Neutral Sheet.106 Sheet.107 Sheet.108 Sheet.109 Sheet.110 Sheet.111 Sheet.112 Sheet.116 Sheet.117 Sheet.118 Sheet.121 Sheet.122 Sheet.123 3 3 3 3 Sheet.127 3 3 3 3 Sheet.130 Sheet.132 Sheet.133 3.8V 3.8V 3.8V 3.3V 3.3V 3.3V 3.3V 3.3V 3.3V Sheet.138 Sheet.139 Connector 1.155.140 Connector 1.155.141 Sheet.142 Sheet.143 Connector 1.155.144 Sheet.145 Connector 1.155.146 Connector 1.155.147 Connector 1.155.148 Phase 1 Phase 1 Phase 1 Phase 2 Phase 2 Phase 2 Phase 3 Phase 3 Phase 3 Neutral Neutral Neutral Connector double arrow.157 Connector double arrow.158 Buck Regulator 1 Buck Regulator Buck Regulator Buck Regulator 2 Buck Regulator Buck Regulator LDO x3 LDO x3 LDO x3 Transceiver Transceiver Transceiver Sub-1GHz Sub-1 GHz Sub-1 GHz PLC Modem PLC Modem PLC Modem GPS + LTE GPS + LTE GPS + LTE Real-Time Clock Real-Time Clock Real-Time Clock Photocoupler x3= 1Per Phase Photocoupler x3= 1 Per Phase Photocoupler x3= 1 Per Phase MCU MCU MCU AFE to MCU x3= 1Per Phase AFE to MCU x3= 1 Per Phase AFE to MCU x3=1 Per Phase Line Driver Line Driver Line Driver AC/DC AC/DC AC/DC Voltage Sensor Circuit x3=1 Per Phase Voltage Sensor Circuit x3= 1 Per Phase Voltage Sensor Circuit x3=1 Per Phase Current Sensor Circuit x3=1 Per Phase Current Sensor Circuit x3= 1 Per Phase Current Sensor Circuit x3= 1 Per Phase
Exiting Interactive Block Diagram