High Voltage DC Bus feedback signal.
High Voltage DC Bus feedback signal.
(OP)
What methods are employed for measuring a 680 VDC bus to provide a 0-4 VDC feedback signal to a microcontroller ADC. The DC bus consists of 2- 450 VDC capacitors connected in series. I had initially considered a voltage divider measuring from the capacitor center tap to positive, but this would require bonding the center tap to GND. The HV DC bus normally floats, would it be acceptable to ground the center tap of the DC bus to GND and likewise the GND reference of the ADC?





RE: High Voltage DC Bus feedback signal.
There are ADC converters and similar devices, that will sense signals and communicate the result digitally over an isolated link. This way you do not need to have your logic common tied to the power system.
RE: High Voltage DC Bus feedback signal.
http://www.lem.com/docs/products/cv%203-1000.pdf
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For the benefit of anyone looking in future: the range goes up to about 6400V AC, 9600V DC.
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If we learn from our mistakes I'm getting a great education!
RE: High Voltage DC Bus feedback signal.
If you fulfill certain design requirements you can even meet strict safety requirements of IEC standards.
RE: High Voltage DC Bus feedback signal.
RE: High Voltage DC Bus feedback signal.
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Don't forget that resistors have voltage ratings. Use several in series for a HV voltage divider.
RE: High Voltage DC Bus feedback signal.
Nominal DC bus voltage is 670 Volts, V-Transducer output 3.5 Vdc @ 670 Vin. Switching transient appears as 7 VDC peak lasting .4 ms
Low ESR DC Bus capacitors and low inductance DC bus design was employed.
Suggestions are welcomed
RE: High Voltage DC Bus feedback signal.
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: High Voltage DC Bus feedback signal.
RE: High Voltage DC Bus feedback signal.
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If we learn from our mistakes I'm getting a great education!
RE: High Voltage DC Bus feedback signal.
I will look into increasing the gate drive resistor value to provide softer switching.
Thank you for the feedback.
Best regards,
Bosko
RE: High Voltage DC Bus feedback signal.
The faster the switch the larger the kicks. A VFD requires balancing the heating of the IGBTs, the efficiency, and the EMI/kick peaks by controlling the drive to the IGBTs to control the current thru the IGBTs.
Keith Cress
kcress - http://www.flaminsystems.com
RE: High Voltage DC Bus feedback signal.
RE: High Voltage DC Bus feedback signal.
The Positive 7 vdc pulse is lasting approximately .4 mS with 4.47 vdc being the trip setpoint. RC filtering at the controller signal input has not improved the situation.