Zero voltage switching

Patent metadata

Field	Value
Publication number	US-9660527-B2
Application number	US-201414585280-A
Country	US
Kind code	B2
Filing date	Dec 30, 2014
Priority date	Mar 24, 2008
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A method for providing non-resonant zero-voltage switching in a switching power converter. The switching power converter converts power from input power to output power during multiple periodic switching cycles. The switching power converter includes a main switch and an auxiliary capacitor adapted for connecting to the main switch, and an inductor connectable to the auxiliary capacitor. When the main switch is on, a previously charged (or previously discharged) auxiliary capacitor is connected to the main switch with auxiliary switches. The main switch is switched off with zero voltage while discharging non-resonantly (charging) the auxiliary capacitor by providing a current path to the inductor. The auxiliary capacitor is disconnected from the main switch. The voltage of the auxiliary capacitor is charged and discharged alternatively during subsequent switching cycles. The voltage of the auxiliary capacitor stays substantially the same until the subsequent turn off of the main switch during the next switching cycle with substantially no energy loss in the auxiliary capacitor.

First claim

The invention claimed is:

1. A method, comprising:
transferring energy from an input through a first switch to an inductor thereby storing the energy on the inductor during first phases of respective periodic switching cycles of a power converter;
transferring the energy stored on the inductor through a second switch to an output during second phases of the respective periodic switching cycles;
changing a voltage at a first node of the inductor by switching at least one auxiliary switch to close a current path to the first node of the inductor through a capacitor while the first and second switches are simultaneously open during transitions from the first phases to the second phases; and
zero volt switching the first switch and the second switch at different times during the transitions between the first phases and the second phases.

2. The method of claim 1 , wherein changing the voltage at the first node of the inductor comprises:
switching at least one auxiliary switch to close a current path through a capacitor and the inductor.

3. The method of claim 1 , wherein switching at least one auxiliary switch comprises:
switching the at least one auxiliary switch to close the current path to the first node by alternatively charging and discharging the capacitor during respective alternating sequential cycles of the periodic switching cycles.

4. The method of claim 3 , wherein switching the at least one auxiliary switch comprises:
during the discharging, switching the at least one auxiliary switch to close a first switched path through the capacitor, inductor, and output; and
during the charging, switching the at least one auxiliary switch to close a second switched path through the capacitor, inductor, and input.

5. The method of claim 3 , wherein the charging and the discharging are non-resonant.

6. The method of claim 1 , wherein a buck stage includes the first and second switches, and the method further comprises:
changing a voltage at a second node of the inductor; and
zero voltage switching at different times third and fourth switches of a boost stage during the transitions between the first and second phases.

7. The method of claim 6 , further comprising:
transferring energy via the third switch to the inductor from a converter input during the first phases; and
transferring the energy via the fourth from the inductor to a converter output during the second phases.

8. A method, comprising:
transferring energy from an input through a first switch to an inductor thereby storing the energy on the inductor during first phases of respective periodic switching cycles of a power converter;
transferring the energy stored on the inductor through a second switch to an output during second phases of the respective periodic switching cycles;
changing a voltage at a first node of the inductor; and
during transitions between the first phases and the second phases, zero voltage switching the first switch from on to off and zero voltage switching the second switch from off to on.

9. The method of claim 8 , wherein changing the voltage at the first node of the inductor comprises:
switching at least one auxiliary switch to close a current path through a capacitor and the inductor.

10. The method of claim 8 , further comprising switching at least one auxiliary switch to close a current path to the first node of the inductor through a capacitor while the first and second switches are simultaneously open during the transitions from the first phases to the second phases.

11. The method of claim 10 , wherein switching the at least one auxiliary switch comprises:
during discharging of the capacitor, switching the at least one auxiliary switch to close a first switched path through the capacitor, inductor, and output; and
during charging of the capacitor, switching the at least one auxiliary switch to close a second switched path through the capacitor, inductor, and input.

12. The method of claim 11 , wherein the charging and the discharging are non-resonant.

13. The method of claim 8 , wherein a buck stage includes the first and second switches, and the method further comprises:
changing a voltage at a second node of the inductor; and
zero voltage switching at different times third and fourth switches of a boost stage during the transitions between the first and second phases.

14. The method of claim 13 , further comprising:
transferring energy via the third switch to the inductor from a converter input during the first phases; and
transferring the energy via the fourth from the inductor to a converter output during the second phases.

15. A method, comprising:
transferring energy from an input through a first switch to an inductor thereby storing the energy on the inductor during first phases of respective periodic switching cycles of a power converter;
transferring the energy stored on the inductor through a second switch to an output during second phases of the respective periodic switching cycles;
changing a voltage at a first node of the inductor;
zero volt switching the first switch and the second switch at different times during transitions between the first phases and the second phases; and
discharging or charging an auxiliary capacitor via a current path through the inductor while the first and second switches are off during the transition from the first phase to the second phase of each respective periodic switching cycle.

16. The method of claim 15 , wherein changing the voltage at the first node of the inductor comprises:
switching at least one auxiliary switch to close a current path through a capacitor and the inductor.

17. The method of claim 15 , further comprising switching at least one auxiliary switch to close a current path to the first node of the inductor through a capacitor while the first and second switches are simultaneously open during the transitions from the first phases to the second phases.

18. The method of claim 17 , wherein switching the at least one auxiliary switch comprises:
during the discharging, switching the at least one auxiliary switch to close a first switched path through the capacitor, inductor, and output; and
during the charging, switching the at least one auxiliary switch to close a second switched path through the capacitor, inductor, and input.

19. The method of claim 17 , wherein the charging and the discharging are non-resonant.

20. The method of claim 15 , wherein a buck stage includes the first and second switches, and the method further comprises:
changing a voltage at a second node of the inductor; and
zero voltage switching at different times third and fourth switches of a boost stage during the transitions between the first and second phases.

21. The method of claim 20 , further comprising:
transferring energy via the third switch to the inductor from a converter input during the first phases; and
transferring the energy via the fourth from the inductor to a converter output during the second phases.

22. A switching converter, comprising:
a first stage comprising: first and second switches, a first auxiliary circuit, an inductor, and a converter input; and
a second stage comprising third and fourth switches, a second auxiliary circuit, the inductor, and a converter output; wherein:
the first and third switches are configured to transfer energy to the inductor from the converter input during first phases of respective periodic switching cycles;
the second and fourth switches are

Assignees

• Solaredge Technologies Ltd
• Solaredge Technologies Ltd

Inventors

• Glovinski Tzachi

Classifications

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M1/34 Primary

  Snubber circuits · CPC title

• H02M7/5387

  in a bridge configuration · CPC title

• H02M2007/4811

  Electricity · mapped topic

• Y02B70/1441

  Cross-Sectional Technologies · mapped topic