I've been working on designing a (220-380 VAC) 3/4 wire phase energy meter and in terms of metrology operation, things were working very well quite similar in terms of metrology if compared to a commercial unit. Now I'm no expert in mains power electronics circuit design so I opted to integrate an off the shelf AC/DC flyback power supply, which when integrated in the meter worked well in lab conditions. I've followed and implemented the mains Input protection circuit going into PSU which is specified by the PSU manufacturer but to be honest I feel helpless as I have no idea how to calculate/know how and why the values are specified in this stage, I need to be able to know how much energy/ voltage and the where bouts of the circuit operates in a surge, fast transient and ESD situation since I plan on doing a pre-compliance test and one of the tests I'm concerned with is if the input protection fails then I have not backup plan so I would really appreciate if someone would kindly share his insights and knowledge on how to pre-simulate or calculate the values of the input circuit below in order to pass the following test conditions below as well.
- Test 2
- Test 3
- Some information on the MOV used on each line (230 VAC
My questions :
- How do you calculate/simulate or choose the correct MOV model/value for the above application to pass the test conditions mentioned above?
- Will the current input stage of the power supply survive the tests mentioned above?
Final Note: I come from an Electronics and Communications background and i have done a reasonable amount of work in low voltage (analog, digital) board designs but I'm no expert in this subject but I'm willing to learn. I know how to simulate how an AC signal going in to a bridge rectifier and analyse the output; you know basic stuff that most of us learned during undergrad, but the (fast transients, etc) on an AC mains situation, I've never worked with such case. I'm having a hard time on how to figure out how to model and simulate the MOV in the simulation programs (LTSpice, Proteus ISIS & TI TINA).