Input filter pre-charge fed by a medium-voltage grid supply

1. A device, comprising:

a transformer configured to supply a pre-charge voltage to a capacitor; and

a converter configured for coupling to the transformer and responsive to an increasing modulation index;

wherein the modulation index increases for a time quanta after the capacitor becomes substantially fully charged; and

wherein the pre-charge voltage is substantially constant during the time quanta.

2. The device of claim 1 , wherein charging occurs from a direct current (DC) side of the device.

3. The device of claim 1 , further comprising an inductor connected in series with a capacitor;

wherein the inductor and the capacitor are coupled to an alternating current (AC) side of the converter; and

wherein the device forms a pre-charging input filter, the input filter being devoid of damping resistors.

4. The device of claim 3 , further comprising a phase locked loop (PLL) coupled between the inductor and a connection port of the device.

5. The device of claim 4 , further comprising a pulse width modulation (PWM) rectifier coupled between an output of the PLL and the converter.

6. The device of claim 5 , further comprising a modulation index module for controlling the modulation index.

7. The device of claim 6 , wherein the modulation index module is programmable.

8. The device of claim 7 , wherein the modulation index increases to a user programmable maximum value.

9. The device of claim 7 , wherein the connection port is configured for coupling to an AC voltage supply.

10. The device of claim 1 , wherein the modulation index is monotonically increasing.

11. The device of claim 1 , wherein the capacitor is a direct current (DC) side component.

12. A method for pre-charging an input filter, comprising:

supplying a pre-charge voltage to a capacitor within the input filter via a transformer; and

converting an alternating current (AC) voltage to a direct current (DC) voltage within the transformer, the converting being responsive to a modulation index;

wherein after the capacitor becomes substantially fully charge charged, a time quanta commences; and

wherein during the time quanta, the modulation index increases and the pre-charge voltage remains substantially constant.

13. The method of claim 12 , wherein the modulation index is a function of an input AC voltage waveform.

14. The method of claim 13 , wherein the modulation index monotonically increases during the time quanta.

15. The method of claim 14 , wherein the modulation index is user programmable.

16. The method of claim 12 , wherein the pre-charge voltage is a DC voltage.

17. A tangible computer-readable medium having stored thereon, computer-executable instructions that, if executed by a computing device, cause the computing device to perform a method comprising:

supplying a pre-charge voltage to a capacitor via a transformer; and

converting an alternating current (AC) voltage to a direct current (DC) voltage within the transformer, the converting being responsive to a modulation index;

wherein after the capacitor becomes substantially fully charge charged, a time quanta commences; and

wherein during the time quanta, the modulation index increases and the pre-charge voltage remains substantially constant.

18. The tangible computer readable medium of claim 17 , wherein the modulation index monotonically increases during the time quanta.

19. The tangible computer readable medium of claim 18 , wherein the modulation index is a function of an input AC voltage waveform.

20. The tangible computer readable medium of claim 19 , wherein the modulation index increases to a user programmable maximum value.