Self-driven AC-DC synchronous rectifier for power applications

• US 8,913,409 B2
• Filed: 10/06/2010
• Issued: 12/16/2014
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Hui, Shu Yuen Ron, Zhong, Wenxing, Choi, Ho Wing
• Primary Examiner(s): Finch, III, Fred E
• Application Number:
  US12/898,898
• Publication Number:
  US 20110199799A1
• Time in Patent Office: 1,532 Days
• Field of Search: 363/21.06, 363/21.14, 363/53, 363/81, 363/84, 363/89, 363/127, 363/49, 363/126
• US Class Current: 363/127
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: H02M 7/2173 in a biphase or polyphase circuit arrangement H02M7/2176 takes precedence; voltage multipliers H02M7/25
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02M 7/2195 the switches being synchronously commutated at the same frequency of the AC input voltage
• 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

Systems, methods, and devices that employ self-driven gate-drive circuitry to facilitate controlling power switches to emulate a diode bridge to synchronously rectify a power signal are presented. A single-phase or multi-phase synchronous rectifier can comprise at least a first pair of switches of a first conducting path and a second pair of switches of a second conducting path that can form or emulate a diode bridge. To facilitate emulating turn-on and turn-off conditions of a diode, a switch can be turned on when voltage across the switch is forward-biased and turned off when switch current is reversed; also, there can be at least one current-controlled switch in each conducting path. Self-driven gate-drive circuitry employs low power components that can facilitate controlling respective switching of the at least first pair and second pair of switches, wherein switching of the switches is also controlled at start-up to emulate a diode bridge.

Claims

1. A system that facilitates synchronous rectification of an input power signal, comprising:

a subset of power switches configured to receive the input power signal and rectify the input power signal to generate a rectified power signal as an output;

a self-driven gate-drive (SDGD) subsystem configured to facilitate control of respective switching of respective power switches of the subset of power switches, wherein the SDGD subsystem is powered by the rectified power signal or the input power signal, wherein the SDGD subsystem comprises a subset of switches that are configured to form an inverter to facilitate the control of switching of a first power switch of the subset of power switches based at least in part on respective switch states of the subset of switches, wherein the SDGD subsystem is further configured to comprise a set of capacitors comprising a first capacitor, a second capacitor, and a third capacitor, and the SDGD subsystem controls respective charging of the first capacitor, the second capacitor, and the third capacitor to charge the first capacitor to a first voltage that is higher than a second voltage of the second capacitor before the third capacitor is charged to a third voltage that satisfies a threshold to switch the first power switch from a first switch state to a second switch state, and wherein the control of the respective charging of the first capacitor, the second capacitor, and the third capacitor facilitates maintaining the first power switch in the first switch state during a start-up phase of operation of the system until the SDGD subsystem is determined to be operating in steady state; and

a zero-crossing controller component configured to facilitate supplying a defined positive voltage signal to a comparator of the SDGD subsystem to facilitate the control of a second power switch of the subset of power switches that is associated with the comparator to switch the second power switch from an on state to an off state at or substantially close to a zero-voltage-crossing point at a half-cycle of the input power signal associated with the second power switch.

2. The system of claim 1, wherein the subset of power switches is further configured to comprise a first high-side power switch, at least one other high-side power switch, a first low-side power switch, and at least one other low-side power switch that are arranged and associated with each other to form and function as a diode bridge to facilitate rectification of the input power signal to generate the rectified power signal, and wherein the first power switch is the first high-side power switch and the second power switch is the first low-side power switch.

3. The system of claim 2, wherein the input power signal is a multi-phase power signal, which has at least three phases, wherein the subset of power switches is further configured to comprise a first high-side power switch, a second high-side power switch, a third high-side power switch, a first low-side power switch, a second low-side power switch, and a third low-side power switch that are arranged and associated with each other to form and function as the diode bridge to facilitate the rectification of the multi-phase power signal to generate the rectified power signal.

4. The system of claim 2, wherein the first high-side power switch and the at least one other high-side power switch are respectively configured to be voltage-controlled self-driven switches, and the first low-side power switch and the at least one other low-side power switch are respectively configured to be current-controlled self-driven switches.

5. The system of claim 4, wherein the SDGD subsystem is further configured to comprise:

a first high-side SDGD component, at least one other high-side SDGD component, a first low-side SDGD component, and at least one other low-side SDGD component, wherein the first high-side SDGD component is configured to comprise voltage-controlled gate-drive circuitry and is associated with the first high-side power switch, the at least one other high-side SDGD component is configured to comprise voltage-controlled gate-drive circuitry and is associated with the at least one other high-side power switch, the first low-side SDGD component is configured to comprise current-controlled gate-drive circuitry and is associated with the first low-side power switch, and the at least one other SDGD component is configured to comprise current-controlled gate-drive circuitry and is associated with the at least one other low-side power switch.

6. The system of claim 5, wherein at least one of the first high-side SDGD component, the at least one other high-side SDGD component, the first low-side SDGD component, or the at least one other low-side SDGD component, is further configured to receive at least a portion of the rectified power signal to facilitate operation of the at least one of the first high-side SDGD component, the at least one other high-side SDGD component, the first low-side SDGD component, or the at least one other low-side SDGD component.

7. The system of claim 4, wherein at least one of the first high-side power switch or the at least one other high-side power switch is respectively configured to be switched from an off state to an on state in response to reception of a forward-biased voltage that satisfies an applicable defined gate threshold switching voltage level, wherein, with respect to the first high-side power switch, the first switch state is the off state and the second switch state is the on state;

and at least one of the first low-side power switch or the at least one other low-side power switch is further configured to be switched from a respective on state to a respective off state in response to current in the at least one of the first low-side power switch or the at least one other low-side power switch being reversed.

8. The system of claim 4, wherein the first high-side power switch, the at least one other high-side power switch, the first low-side power switch, and the at least one other low-side power switch are arranged in a circuit with respect to each other to facilitate function of the subset of power switches as the diode bridge in order to facilitate the rectification of the input power signal to generate the rectified power signal, during the start-up phase of operation prior to steady-state operation of the SDGD subsystem.

9. The system of claim 4, wherein the first high-side power switch, the at least one other high-side power switch, the first low-side power switch, and the at least one other low-side power switch are further configured to include respective body diodes to facilitate function of the subset of power switches as the diode bridge in order to facilitate the rectification of the input power signal to generate the rectified power signal, during the start-up phase of operation prior to steady-state operation of the SDGD subsystem.

10. The system of claim 1, wherein the SDGD subsystem is further configured to include a high-side SDGD portion and a low-side SDGD portion that are symmetrical, and wherein the high-side SDGD portion is configured to comprise the subset of switches and the set of capacitors to facilitate the control of the switching of the first power switch.

11. The system of claim 1, wherein the input power signal has a voltage level that is greater than or equal to 100 volts.

12. The system of claim 1, wherein at least one power switch of the subset of power switches is further configured to be a metal-oxide-semiconductor field-effect transistor (MOSFET) switch.

13. A method comprising:

generating a rectified power signal in response to an input power signal received by a subset of power switches, wherein respective power switches of the subset of power switches are arranged with respect to each other to emulate functionality of a diode rectifier;

supplying at least a portion of the rectified power signal to a self-driven gate-drive (SDGD) subsystem associated with the subset of power switches to facilitate controlling respective switching of the respective power switches of the subset of power switches, wherein the SDGD subsystem comprises a subset of switches that form an inverter to facilitate the controlling of the switching of a first power switch of the subset of power switches based at least in part on respective switch states of the subset of switches;

controlling respective charging of a first capacitor, a second capacitor, and a third capacitor of the SDGD subsystem to charge the first capacitor to a first voltage that is higher than a second voltage of the second capacitor before the third capacitor is charged to a third voltage that facilitates switching the first power switch from a first switch state to a second switch state, wherein the controlling of the respective charging of the first capacitor, the second capacitor, and the third capacitor facilitates maintaining the first power switch in the first switch state during initiation of the SDGD subsystem until the SDGD subsystem is operating in steady state; and

supplying a defined positive voltage signal to a comparator of the SDGD subsystem to facilitate controlling switching of a second power switch of the subset of power switches that is associated with the comparator to switch the second power switch from an on state to an off state at or substantially close to a zero-voltage-crossing point at a half-cycle associated with the input power signal.

14. The method of claim 13, further comprising:

controlling at least one of a first high-side power switch or at least one other high-side power switch to switch from an off state to an on state in response to receiving a forward-biased voltage that satisfies an applicable defined gate threshold switching voltage level; and

controlling at least one of a first low-side power switch or at least one other low-side power switch to switch from an on state to an off state in response to sensing a reversing of current in at least one of the first low-side power switch or the at least one other low-side power switch, wherein the subset of power switches comprises the first high-side power switch, the at least one other high-side power switch, the first low-side power switch, and the at least one other low-side power switch, wherein the first power switch is the first high-side power switch and the second power switch is the first low-side power switch.

15. The method of claim 13, further comprising:

controlling switching of at least one of a first high-side power switch or at least one other high-side power switch to switch at least one of the first high-side power switch or the at least one other high-side power switch to an off state, during a period of time that the SDGD subsystem is not operating in the steady state, wherein the subset of power switches comprises the first high-side power switch and the at least one other high-side power switch, wherein the first power switch is the first high-side power switch, and, with respect to the first power switch, the first switch state is the off state.

16. The method of claim 13, further comprising:

controlling switching of at least one of a first low-side power switch or at least one other low-side power switch to switch at least one of the first low-side power switch or the at least one other low-side power switch to an off state, during a period of time that the SDGD subsystem is not operating in the steady state, wherein the subset of power switches comprises the first low-side power switch and the at least one other low-side power switch, wherein the second power switch is the first low-side power switch.

17. The method of claim 13, wherein the input power signal has a voltage level that is greater than or equal to 100 volts.

18. A self-driven synchronous rectifier device, comprising:

a subset of power switches that is configured to receive an input voltage signal and rectify the input voltage signal to generate a rectified voltage signal as an output;

a self-driven gate-drive (SDGD) subsystem that is configured to control respective switching of respective power switches in the subset of power switches, wherein the SDGD subsystem is further configured to receive at least a portion of the rectified voltage signal, wherein the SDGD subsystem comprises a subset of switches that form an inverter to facilitate the controlling of the switching of a first power switch of the subset of power switches based at least in part on respective switch states of the subset of switches, and wherein the SDGD subsystem is further configured to comprise a set of capacitor components comprising a first capacitor component, a second capacitor component, and a third capacitor component, and, to facilitate maintaining the first power switch in a first switch state until the SDGD subsystem is operating in steady state, the SDGD subsystem controls respective charging of the first capacitor component, the second capacitor component, and the third capacitor component to charge the first capacitor component to a first voltage that is higher than a second voltage of the second capacitor component before the third capacitor component is charged to a third voltage that is sufficient to switch the first power switch from the first switch state to a second switch state; and

a zero-crossing controller component configured to provide a defined positive voltage signal to a comparator of the SDGD subsystem to facilitate control of a second power switch of the subset of power switches that is associated with the comparator to switch the second power switch from an on state to an off state at or substantially near a zero-voltage-crossing point at a half-cycle of the input power signal.

19. The synchronous rectifier device of claim 18, wherein the subset of power switches is further configured to comprise a first high-side power switch, at least one other high-side power switch, a first low-side power switch, and at least one other low-side power switch that are arranged and associated with each other to form and operate as a diode bridge to facilitate rectification of the input voltage signal to generate the rectified voltage signal, and wherein the first power switch is the first high-side power switch and the second power switch is the first low-side power switch.

20. The synchronous rectifier device of claim 18, wherein the subset of power switches is further configured to comprise a first high-side power switch, at least one other high-side power switch, a first low-side power switch, and at least one other low-side power switch that are arranged in a circuit to maintain the first high-side power switch, the at least one other high-side power switch, the first low-side power switch, and the at least one other low-side power switch in an off state, during a period of time that the SDGD subsystem is not operating in the steady state, to facilitate function of the subset of power switches as a diode bridge in order to facilitate rectification of the input power signal to generate the rectified power signal, and wherein the first power switch is the first high-side power switch and the second power switch is the first low-side power switch, and, with respect to the first power switch, the first switch state is the off state.