Charger design

This is a companion post to the BCB pictures post. It makes sense to check all pictures and text there first.

A student in high power electronics contacted me to discuss some design issues and pointed me to this US patent. Doing some comparing it is obvious that the BCB is designed exactly according to the patent. So here is some extra information linking the picture and figure 2 from the patent, reproduced here.

  • The EMC filter (5a) is not in the image. It also contains the 1/3 phase switching (see this post). Maybe I will get my hands on some later.
  • The capacitor bank (5b) is the blue box;
  • The regulated rectifier (11, 12) and it’s control circuit (6) is the black plastic box. It’s incoming connectors are bolted on the capacitor bank with it’s three phases connectors, and it’s bottom is thermally bolted against the aluminium housing for cooling. This can be seen in the other BCB pictures. We suspect so is the free wheeling diode (13);
  • The potted aluminum device is a 93 uH inductor (the label in the picture is in error, thank you user pixel from It is inserted in the line going to A (10);
  • The input current measuring device (10) might be tucked away in the far top left corner close to the Neutral point connector, which is actually the center wire of the motor (14). The current sensor is probably a Hall sensor. It’s control wire (blue-white in the picture, (8) in the schematic, running to the control circuit (6);
  • Everything else in the picture is control wires, CANbus and 400 volt distribution;
  • The entire inverter section (15, 16, 7) is located in the PEB.

Note that this setup allows for both buck and boost operation, which is needed because rectified voltage is too low when in single phase operation (325 V peak) and too high in three phase operation (562 V peak) for the battery (roughly 350 – 420 V).

Notice the micro-switch at the left side detecting opening the cover. Hmmmmm.

It’s all rather cleverly done.

4 Comments on “Charger design

    • Hmmmmm, interesting post there on forumpro, with interesting timing. Of course the schematic is not mine. But no attribution? Oh well, the internet 😉

      I must confess I do not exactly understand your question. In one phase operation, N is most definitely used of course. But I am pretty sure through my conversation with the Renault technician the one phase operation is not implemented through the schematic posted on the fr forum, but the way I described it (N being connected through a relay to L3). This was the described failure.

    • What you are showing are filter coils in the feed line. If you look at the patent, there are no input coils (in fact there are, but those are in the part called EMC (filter) in the schematic I posted. The motor coil is used for buck-boost conversion. Power factor correction is done exactly as stated, which happens to be as the schematic you posted.

      Note that because of the filter capacitors on the input line it is no so much power factor compensation for the grid.

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