astra_conv:conversion:dcdc_converter:dcdc_converter
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision | |||
|
astra_conv:conversion:dcdc_converter:dcdc_converter [2014/06/20 12:53] richard |
astra_conv:conversion:dcdc_converter:dcdc_converter [2014/06/20 13:02] (current) richard |
||
|---|---|---|---|
| Line 69: | Line 69: | ||
| The bottom center building block is the current limiter, that avoids overcurrent shutdown. It is required only for the second device that I integrated, and the device really should feel ashamed for it's deficiencies. You may notice that I placed the shunt resistor and the power MOSFET into the return line, so that the negative output of the DC/DC converter is below ground potential. Reason is simply because this will work with an n channel FET, which particularly has lower "on" resistance than it's p channel counterparts. The control circuit based on an old-fashioned operational amplifier allows to use a very small shunt resistor (10 mOhms), that gives a voltage drop of only 300mV at 30Amps. Despite my concerns, the circuit is reacting quick enough to prevent shutdown of the converter, and so far proved to run stable without oscillations. | The bottom center building block is the current limiter, that avoids overcurrent shutdown. It is required only for the second device that I integrated, and the device really should feel ashamed for it's deficiencies. You may notice that I placed the shunt resistor and the power MOSFET into the return line, so that the negative output of the DC/DC converter is below ground potential. Reason is simply because this will work with an n channel FET, which particularly has lower "on" resistance than it's p channel counterparts. The control circuit based on an old-fashioned operational amplifier allows to use a very small shunt resistor (10 mOhms), that gives a voltage drop of only 300mV at 30Amps. Despite my concerns, the circuit is reacting quick enough to prevent shutdown of the converter, and so far proved to run stable without oscillations. | ||
| - | On the right side of the diagram, you find the output relay already mentioned above (and also discussed in the chapter "distribution boxes" - since it is located in the front 12V distribution box). Delayed switch-on is achieved by sensing the output voltage of the DC/DC converter (after the current limiter). | + | On the right side of the diagram, you find the output relay already mentioned above (and also in the chapter "distribution boxes" - since it is located in the front 12V distribution box). Delayed switch-on is achieved by sensing the output voltage of the DC/DC converter (after the current limiter). The relay will only be triggered after this voltage has exceeded around 10V. Without this delay, there would be a high reverse inrush current from the 12V battery to the DC/DC converter, which would cause the relay contact to "stick". |
| The output relay is controlled by a separate diode combiner located on the DC/DC primary side driver board. | The output relay is controlled by a separate diode combiner located on the DC/DC primary side driver board. | ||
astra_conv/conversion/dcdc_converter/dcdc_converter.txt · Last modified: 2014/06/20 13:02 by richard
Page Tools
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Share Alike 4.0 International
