SLUAB06 January   2025 AMC131M02 , AMC3330 , ISO7731 , UCC33421

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Topologies for Insulation Monitoring in ESS
    1. 2.1 Single Switch Topology
      1. 2.1.1 Test Steps
    2. 2.2 Dual Switch Floating Sampling Topology
      1. 2.2.1 Test Steps
    3. 2.3 Dual Switch Sampling in High Voltage Side Topology
    4. 2.4 AC Injection Topology
  6. 3Comparison of Designs
    1. 3.1 Injection Resistance Influence on Accuracy
  7. 4Capacitor Influence on Sampling Time
    1. 4.1 How to Choose Y Capacitor
    2. 4.2 Sampling Time
  8. 5Key Devices
    1. 5.1 BQ79731-Q1
    2. 5.2 UCC33421-Q1
    3. 5.3 AMC131M02
    4. 5.4 AMC3330
    5. 5.5 ISO773x
  9. 6Topos Simulation Result and Conclusion
  10. 7Summary
  11. 8References

2.3 Dual Switch Sampling in High Voltage Side Topology

Use topo3-dual switch, sampling ADC and control signal put on the high voltage side with isolated operational amplifier for high-voltage sampling and insulation monitoring. Topo and device requirement based on dielectric strength as following:

Dual Switch, Sample GND Connected to HV(topo3)Figure 2-15 Dual Switch, Sample GND Connected to HV(topo3)
Topo3-Communication and PE②4380VFigure 2-17 Topo3-Communication and PE②4380V
Topo3-HV and Communication④ 4380VFigure 2-19 Topo3-HV and Communication④ 4380V
Topo3-HV(BAT+ or BAT-) and PE①5880VFigure 2-16 Topo3-HV(BAT+ or BAT-) and PE①5880V
Topo3-HV and LV(MCU)③4380VFigure 2-18 Topo3-HV and LV(MCU)③4380V
Topo3-LV and Communication⑤4380VFigure 2-20 Topo3-LV and Communication⑤4380V

Test steps:

  1. Close SW1&SW3, open SW2, get V+.
  2. Close SW2 open SW1, get V-.
  3. Put V+ and V- into Risop and RisoN calculate formula.

Calculate formula and worst case are the same as the Topo2 because the difference is only sampling point position and does not influence the formula.