Synchronous DC-DC power converter with a single power storage element
The present invention relates to a synchronous DC-DC power converter which may include a conversion cell including a number of switches and a single inductor, and a controller. The controller is configured to control a cycle of conversion of the conversion cell of the converter with multiple phases by controlling each of the switches.
1. The synchronous DC-DC converter including:
a first converter input including a first input voltage that is electrically connected to a first bidirectional switch;
a second converter input including a second input voltage that is electrically connected to a second bidirectional switch;
a power storage element;
a third switch, wherein an output of the first converter input and or the second converter input is electrically connected to an input of the power storage element and to the third switch, the third switch is connected to a ground;
a fourth switch;
a fifth switch;
a converter output including an output voltage, wherein the output of the power storage element is connected to the fourth switch and to the fifth switch, the fourth switch is connected to the ground and the fifth switch is connected to the converter output in connection with a capacitor; and
a controller configured to control a cycle of conversion of the DC-DC converter with multiple phases by controlling each of the switches, where:
at least one boost phase has one of the first and second bidirectional switches ON to connect to the input of the power storage element, and the fourth switch ON to connect the output of the power storage element to the ground while all other switches are OFF;
at least one through phase has one of the first and second bidirectional switches ON to connect to the input of the power storage element, and the fifth switch ON to connect the output of the power storage element to the converter output while all other switches are OFF; and
at least one buck phase has the third switch ON to connect the ground to the input of the power storage element, and the fifth switch ON to connect the output of the power storage element to the converter output while all other switches are OFF.
2. The synchronous DC-DC converter of claim 1 , wherein the controller is configured to order the phases of the cycle of conversion as: the at least one boost phase, the at least one through phase, and then the at least one buck phase.
3. The synchronous DC-DC converter of claim 1 , wherein the at least one boost phase includes a first boost phase for the first converter input where the first bidirectional switch is ON to connect to the input of the power storage element, and the fourth switch is ON to connect the output of the power storage element to the ground while all other switches are OFF, and a second boost phase for the second converter input where the second bidirectional switch is ON to connect to the input of the power storage element, and the fourth switch is ON to connect the output of the power storage element to the ground while all other switches are OFF.
4. The synchronous DC-DC converter of claim 3 , wherein the at least one through phase includes a first through phase where the first bidirectional switch is ON to connect to the input of the power storage element, and the fourth switch is ON to connect the output of the power storage element to the ground while all other switches are OFF, and a second through phase where the second bidirectional switch is ON to connect to the input of the power storage element, and the fourth switch is ON to connect the output of the power storage element to the ground while all other switches are OFF.
5. The synchronous DC-DC converter of claim 4 , wherein the controller groups the first and second boost phases together in the cycle of conversion of the DC-DC converter so the fifth switch is changed only twice in the cycle.
6. The synchronous DC-DC converter of claim 4 , wherein the controller groups the first and second through phases together in the cycle of conversion of the DC-DC converter so the third switch is changed only twice in the cycle.
7. The synchronous DC-DC converter of claim 6 , wherein the controller selects the first through phase in the cycle of conversion to use the same one of the first and second converter inputs used in a buck phase of a previous cycle.
8. The synchronous DC-DC converter of claim 4 , wherein the controller alternates the first and second boost phases with the first and second through phases in the cycle of conversion of the DC-DC converter if the output voltage is below either of the first or second input voltages.
9. The synchronous DC-DC converter of claim 4 , wherein the controller adds additional buck phases after the first and second boost phases, respectively, in the cycle of conversion of the DC-DC converter if either first or second input voltage is above the output voltage.
10. The synchronous DC-DC converter of claim 1 , further including a further converter output including a further output voltage, wherein the output of the power storage element is additionally connected to a sixth switch, the sixth switch is connected to the further converter output in connection with a capacitor.
11. The synchronous DC-DC converter of claim 10 , wherein the controller is further configured to control each of the switches where the at least one through phase has the fifth switch and then the sixth switch ON sequentially, and the at least one buck phase has the fifth switch and then the sixth switch ON sequentially.
12. The synchronous DC-DC converter of claim 1 , wherein the synchronous DC-DC converter is configured to operate in Discontinuous Conduction Mode (DCM), and the synchronous DC-DC converter includes a DCM phase which has the third switch or the fifth switch ON while all other switches are OFF.
13. The synchronous DC-DC converter of claim 12 , wherein the controller is configured to order the phases of the cycle of conversion as: the at least one boost phase, the at least one through phase, the at least one buck phase, and then the DCM phase.
14. The synchronous DC-DC converter of claim 1 , wherein the controller operates the DC-DC converter bidirectionally to provide the output voltage to one of the first or second converter inputs.
15. The synchronous DC-DC converter of claim 1 , wherein the power storage element is an inductor.
16. The synchronous DC-DC converter of claim 1 , further including a plurality of conversion cells, each of the conversion cells include: the first converter input, the first bidirectional switch, the second converter input, the second bidirectional switch, the power storage element, the third switch, the fourth switch, the fifth switch, and the converter output.
17. The synchronous DC-DC converter of claim 16 , wherein the conversion cells are connected in parallel to increase current capacity of the converter.
18. A method of controlling the synchronous DC-DC converter of claim 1 , the method including:
receiving input measurements from the first converter input and the second converter input at the controller;
the controller calculating cycles of conversion of the DC-DC converter based on at least the input measurements; and
the controller generating Pulse Width Modulation (PWM) settings to control switching of each of the switches to control the cycles of conversion of the DC-DC converter.
19. The method of claim 18 , further including the controller calculating the cycles of conversion of the DC-DC converter based on one or more of:
input constraints associated with the first and second converter inputs;
output constraints associated with the converter output;
output measurements from the converter output; and
a maximum current of the power storage element constraint.