Zero voltage switching

• US 8,111,052 B2
• Filed: 03/24/2009
• Issued: 02/07/2012
• Est. Priority Date: 03/24/2008
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Glovinsky, Tzachi
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US12/409,604
• Publication Number:
  US 20090237042A1
• Time in Patent Office: 1,050 Days
• Field of Search: 323/222, 323/223, 323/224, 323/259, 323/282, 323/344, 323/225, 323/268, 323/271, 323/272
• US Class Current: 323/225
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 7/4811 having auxiliary actively switched resonant commutation circuits connected to intermediate DC voltage or between two push-pull branches
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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 switch and an auxiliary capacitor adapted for connecting in parallel with the switch, and an inductor connectable to the auxiliary capacitor. The main switch is on. A previously charged (or previously discharged) auxiliary capacitor is connected across the main switch with auxiliary switches. The main switch is switched off with zero voltage while discharging (charging) the auxiliary capacitor by providing a current path to the inductor. The auxiliary capacitor is disconnected from the 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.

Claims

1. A switching converter comprising:

a plurality of main switches interconnected in a full bridge topology, said main switches including a first switch, a second switch, a third switch and a fourth switch, wherein a pair of input voltage terminals are attachable at a first node connecting said first and third switches and at a second node connecting said second and fourth switches;

wherein a first output voltage terminal is operatively attached at a third node connecting said third and fourth switches and a second output voltage terminal is operatively attached at a fourth node connecting said first and second switches;

a plurality of bidirectional switches interconnected in a full bridge topology, said bidirectional switches including a first bidirectional switch, a second bidirectional switch, a third bidirectional switch and a fourth bidirectional switch, wherein said third node connects said first and third bidirectional switches and said fourth node connects said second and fourth bidirectional switches; and

an auxiliary capacitor connected at one end at a node connecting said first and second bidirectional switches and at the other end at a node connecting said second and fourth bidirectional switches.

2. The switching converter according to claim 1,

wherein the auxiliary capacitor is previously charged in a first switching cycle when at least one of the main switches is on, and the auxiliary capacitor is connected to the at least one main switch;

wherein said at least one main switch is switched off at zero voltage while discharging the auxiliary capacitor by providing a current path to the inductor;

wherein the auxiliary capacitor is disconnected from said at least one main switch; and

wherein voltage of the auxiliary capacitor is charged and discharged alternatively during a plurality of switching cycles, wherein the voltage of the auxiliary capacitor stays substantially the same until the subsequent turn-off of said at least one main switch during the next switching cycle with substantially no energy loss in the auxiliary capacitor.

3. The switching converter according to claim 1, further comprising:

a first inductor attachable between said first output voltage terminal and said third node; and

a second inductor attachable between said second output voltage terminal and said fourth node.

4. The switching converter according to claim 3, wherein said first and second inductor is a single split inductor.

5. The switching converter according to claim 3, wherein said first and second inductor is a single inductor connected in series to a transformer primary.

6. The switching converter according to claim 3,

wherein during a second switching cycle, said auxiliary capacitor is discharged by providing at least one current path to at least one of said inductors;

wherein energy stored within the auxiliary capacitor not dissipated by the switching converter.