A method of controlling the connection of a multiple phase power source to a plurality of capacitors. The method including, for each phase of the power source, determining a first voltage using a first voltage divider, the first voltage divider having a first high voltage resistor and a first low voltage resistor, wherein the first voltage is equal to a voltage across the first low voltage resistor. The method further including, for each phase of the power source, determining a second voltage across using a second voltage divider, the second voltage divider having a second high voltage resistor and a second low voltage resistor, wherein the second voltage is equal to a voltage across the second low voltage resistor. The method further including, for each phase of the power source, generating a close signal when the difference between the first voltage and the second voltage is approximately zero.