Secondary-side controlled resonant AC voltage regulator module

• US 6,262,905 B1
• Filed: 11/22/1999
• Issued: 07/17/2001
• Est. Priority Date: 11/22/1999
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Steigerwald, Robert Louis, Zhang, Richard S.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Laxton, Gary L.
• Application Number:
  US09/442,324
• Time in Patent Office: 603 Days
• Field of Search: 363/15, 363/16, 363/84, 363/89, 363/125, 363/127, 323/223-225
• US Class Current: 363/127
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• 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 secondary-side controlled series resonant AC voltage controlled module (VRM) converts an AC distribution bus voltage to a low DC voltage for providing power to high speed microprocessors and integrated circuits, with minimal conduction and switching losses, providing high efficiency even at low output voltage, high current and high switching frequency.

Claims

1. An AC voltage regulator module (VRM) for converting an AC distribution bus voltage to a regulated DC voltage, comprising:

a resonant tank circuit for coupling the AC VRM to the AC distribution bus;

a secondary-side power conversion stage coupled to the resonant tank circuit via an isolation transformer, the power conversion stage comprising a pair of bi-directional switches coupled to the resonant tank circuit via the isolation transformer, the bi-directional switches rectifying the AC bus voltage and providing the regulated DC voltage, each bi-directional switch comprising a dual-device switch comprising a main switch coupled to an auxiliary branch, the auxiliary branch comprising an auxiliary switch coupled in series with a diode, the dual-device switch further comprising a fixed delay circuit for providing a fixed delay between turn on and turn off of the main switch and the auxiliary switch; and

a secondary-side control for alternately turning on and off the bi-directional switches based on the polarity of the AC bus voltage and based on controlled timing in order to minimize switching and conduction losses and to provide the regulated DC voltage.

2. The AC VRM of claim 1 wherein the resonant tank circuit comprises a series resonant tank circuit.

3. The AC VRM of claim 1, further comprising means for limiting a voltage across each respective bi-directional switch at turn-off in order to avoid a reverse bias turn-on of the other AC switch.

4. The AC VRM of claim 3, wherein the means for limiting a voltage across each respective bi-directional switch comprises a saturable reactor on the primary side of the isolation transformer for removing the path between the primary and secondary sides of the isolation transformer after each respective AC bi-directional switch turns off.

5. The AC VRM of claim 3 wherein the means for limiting a voltage across each respective bi-directional switch comprises a resistor-capacitor-diode voltage clamp circuit coupled to each AC switch.

6. The AC VRM of claim 1 wherein the gate controller comprises means for increasing the negative gate drive voltage to each respective AC bi-directional switch at turn-off in order to avoid a reverse bias turn-on of the other bi-directional switch.

7. An AC voltage regulator module (VRM) for converting an AC distribution bus voltage to a regulated DC voltage, comprising:

a series resonant tank circuit for coupling the AC VRM to the AC distribution bus;

a secondary-side power conversion stage coupled to the resonant tank circuit via an isolation transformer, the power conversion stage comprising a pair of AC switches coupled to the resonant tank circuit via an isolation transformer, the AC switches rectifying the AC bus voltage and providing the regulated DC voltage, the AC switches each comprising a dual-device switch comprising a main switch coupled to an auxiliary branch, the auxiliary branch comprising an auxiliary switch coupled in series with a diode, each dual-device switch further comprising a fixed delay circuit for providing a fixed delay between turn on and turn off of the main switch and the auxiliary switch; and

a gate controller for alternately turning on and off the AC switches based on the polarity of the AC bus voltage and based on controlled timing in order to minimize switching and conduction losses and to provide the regulated DC voltage.

8. The AC VRM of claim 7 wherein each AC switch comprises a CHFET.

9. The AC VRM of claim 7, further comprising a snubber circuit coupled to each AC switch.

10. The AC VRM of claim 7, further comprising means for limiting a voltage across each respective AC switch at turn-off in order to avoid a reverse bias turn-on of the other AC switch.

11. The AC VRM of claim 7 wherein the means for limiting a voltage across each respective AC switch comprises a saturable reactor on the primary side of the isolation transformer for removing the path between the primary and secondary sides of the isolation transformer after each respective AC switch turns off.

12. The AC VRM of claim 11 wherein the means for limiting a voltage across each respective AC switch comprises a resistor-capacitor-diode voltage clamp circuit coupled to each AC switch.

13. The AC VRM of claim 11 wherein the gate controller further comprises means for increasing the negative gate drive voltage to each respective AC switch at turn-off in order to avoid a reverse bias turn-on of the other AC switch.