GoldenMotor.com Forum

General Category => General Discussions => Topic started by: Justin824 on April 18, 2017, 11:23:34 PM

Title: Bulk capacitance to limit ripple?
Post by: Justin824 on April 18, 2017, 11:23:34 PM

I am running a 48V 3KW air-cooled BLDC golden motor connected to a VEC200 controller. This is being powered by a 48VDC battery pack. The motor current is about 60A. There is 10 feet of cabling between the battery pack and the controller.

Does golden recommend adding bulk capacitance to the controller when there is extra cabling between the controller and power source? If so, how much?

Title: Re: Bulk capacitance to limit ripple?
Post by: Justin824 on May 01, 2017, 02:16:50 PM

Followup: I contacted Golden and they said that no extra bulk capacitance was needed. I was surprised at this but that's what they said.

Title: Re: Bulk capacitance to limit ripple?
Post by: Bikemad on May 01, 2017, 08:46:15 PM

Quote from: https://www.rcgroups.com/forums/showthread.php?788065-very-high-power-controllers-e-g-60V-200A/page4#post33264587

Distance between battery and block-ESC is critical because block-ESC introduce current-peaks on DC-line which induce voltage-spikes. This voltage spikes are dangerous for the MOSFETs. To compensate this DC-input-caps are used to take-over the induced energy and so keep voltage-peaks lower.
Long DC-lines will increase inductance and with this also amount of induced voltage. To overcome this, there is a rule-by-thumb to add some 100µF distributed each 10..20cm along the DC-line. These additional caps are not needed for sine-ESC, because no sharp changes of DC-current are produced with (smooth) sine-shaped currents.

Apparently, this is not a problem that would affect the VEC (sine wave) controllers.

Alan