Electric power converter

An electric power converter comprising:

• a first input-output part;
• a first capacitor and a second capacitor which are connected in series;
• a second input-output part connected with the first and second capacitors;
• an inductor connected with a positive electrode side or a negative electrode side of the first input-output part;
• a first switch with which the positive electrode side of the first input-output part is connected with the positive electrode side of the first capacitor and the positive electrode side of the second input-output part;
• a second switch with which the positive electrode side of the first input-output part is connected with the negative electrode side of the first capacitor and the positive electrode side of the second capacitor;
• a third switch with which the negative electrode side of the first input-output part is connected with the negative electrode side of the first capacitor and the positive electrode side of the second capacitor;
• a fourth switch with which the negative electrode side of the first input-output part is connected with the negative electrode side of the second capacitor and the negative electrode side of the second input-output part;
• and
• a control circuit which turns ON/OFF from the first switch to the fourth switch,
• wherein the control circuit controls in a step-up mode to have a period for which the second and third switches are alternately turned ON or OFF and a period for which the second and third switches are simultaneously turned ON,
• in a step-down mode, to have a period for which the first and fourth switches are alternately turned ON or OFF and the first and fourth switches are simultaneously turned ON.

An electric power converter comprising:

• an input part;
• a first capacitor and a second capacitor which are connected in series;
• an output part connected with the first capacitor and the second capacitor;
• an inductor connected with a positive electrode side or a negative electrode side of the input part;
• a first switch with which the positive electrode side of the input part is connected with a negative electrode side of the first capacitor and a positive electrode side of the second capacitor;
• a second switch with which the negative electrode side of the input part is connected with the negative electrode side of the first capacitor and the positive electrode side of the second capacitor;
• and
• a control circuit which turns adapted to turn ON/OFF the first switch and the second switch,
• wherein the control circuit controls operation of the first and second switches in a step-up mode in Modes 1, 2, and 3, in the following sequence:
• Mode 1, Mode 2, Mode 1, Mode 3, Mode 1, Mode 2, Mode 1, Mode 3, and so on,
• wherein during the Mode 1, which extends for a first predetermined time period, the first and second switches are simultaneously turned ON,
• during Mode 2, which extends for a second predetermined time period, the first switch is turned ON and the second switch is turned OFF, and
• during Mode 3, which extends for a third predetermined time period, the first switch is turned OFF and the second switch is turned ON;
• wherein the first and second switches are in series with third and fourth switches.

An electric power converter comprising:

• an output part;
• a first capacitor and a second capacitor which are connected in series;
• an input part connected with the first capacitor and the second capacitor;
• an inductor connected with a positive electrode side or a negative electrode side of the output part;
• a first switch with which the positive electrode side of the output part is connected with a positive electrode side of the first capacitor and a positive electrode side of the input part;
• a second switch with which the negative electrode side of the output part is connected with a negative electrode side of second capacitor and a negative electrode side of the input part;
• and
• a control circuit adapted to turn ON/OFF the first switch and the second switch,
• wherein the control circuit controls operation of the first and second switches in a step-down mode in Modes 1, 2, and 3, in the following sequence:
• Mode 1, Mode 2, Mode 1, Mode 3, Mode 1, Mode 2, Mode 1, Mode 3, and so on,
• wherein during the Mode 1, which extends for a first predetermined time period, the first and second switches are simultaneously turned ON,
• during Mode 2, which extends for a second predetermined time period, the first switch is turned ON and the second switch is turned OFF, and
• during Mode 3, which extends for a third predetermined time period, the first switch is turned OFF and the second switch is turned ON;
• wherein the first and second switches are in series with third and fourth switches.