Predictive switching control for an active rectifier

Patent metadata

Field	Value
Publication number	US-10164547-B2
Application number	US-201715667846-A
Country	US
Kind code	B2
Filing date	Aug 3, 2017
Priority date	Apr 18, 2017
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A method and a system for controlling a rectifier can obtain a predicted switching interval. The method includes steps of: receiving frequency information and line information of a power generator, the line information including a switching point where a voltage or current crosses zero and a switching interval based on the frequency information; obtaining a predicted switching interval according to the frequency information and the line information, and obtaining a feedback signal according to two terminals of at least one component of the rectifier; and switching a switching signal of the rectifier within the predicted switching interval according to the feedback signal.

First claim

What is claimed is:

1. A method for controlling a rectifier, comprising:
obtaining frequency information and line information of a power generator, the line information comprising:
a switching point that is a time point at which a voltage or a current of the power generator crosses zero; and
a switching interval having a first duration of up to a half period corresponding to a reciprocal of the frequency information, wherein the switching point is at a center of the switching interval;

obtaining a predicted switching interval according to the frequency information and the line information, and obtaining a feedback signal according to a first terminal and a second terminal of at least one switching component of the rectifier; and
switching a switching signal of the rectifier within the predicted switching interval according to the feedback signal, wherein the switching signal is switched to cause the switching component to be in an on state or in a conducting state if a voltage of the first terminal is greater than a voltage of the second terminal within the predicted switching interval, and the switching signal is switched to cause the switching component to be in an off state or in a non-conducting state if the voltage of the first terminal is less than the voltage of the second terminal within the predicted switching interval.

2. The method of claim 1 , wherein the frequency information is obtained by zero crossing detection of a voltage or a current of the power generator.

3. The method of claim 1 , wherein a next switching point is the half period corresponding to the reciprocal of the frequency information away from the switching point.

4. The method of claim 3 , wherein the predicted switching interval has a second duration of up to the half period corresponding to the reciprocal of the frequency information, and the next switching point is a center of the predicted switching interval.

5. The method of claim 1 , wherein switching the switching signal of the rectifier further includes determining current direction information between the two terminals of the at least one switching component of the rectifier within the predicted switching interval.

6. The method of claim 1 , further comprising, after switching the switching signal of the rectifier within the predicted switching interval, determining if a time point for switching the switching signal is in a middle point of the predicted switching interval, and calculating a shift that the time point for switching the switching signal is shifted from the middle of the predicted switching interval if the time point is not in the middle point of the predicted switching interval.

7. The method of claim 6 , further comprising calibrating a next time point for switching the switching signal based on the shift that the time point for switching the switching signal is shifted from the middle point of the predicted switching interval, wherein the next time point for switching the switching signal is at the middle point of a next predicted switching interval.

8. The method of claim 1 , further comprising, after switching the switching signal of the rectifier within the predicted switching interval, detecting if there is a reverse current in the predicted switching interval, and switching the switching signal of the rectifier again if there is the reverse current in the predicted switching interval.

9. A system for controlling a rectifier, comprising:
a power generator;
a rectifying unit including a plurality of switching components; and
a control unit including:
a frequency access module configured for obtaining frequency information and line information of the power generator;
a switching interval generation module configured for obtaining a predicted switching interval according to the frequency information and the line information, the line information comprising:
a switching point that is a time point at which a voltage or a current of the power generator crosses zero; and
a switching interval having a first duration of up to a half period corresponding to a reciprocal of the frequency information, wherein the switching point is at a center of the switching interval; and

a switching control module configured for obtaining a feedback signal and controlling a switching signal of at least one of the plurality of switching components within the predicted switching interval according to the feedback signal, wherein the feedback signal is obtained according to a first terminal and a second terminal of the at least one of the plurality of switching components, wherein the switching signal is switched to cause the switching component to be in an on state or in a conducting state if a voltage of the first terminal is greater than a voltage of the second terminal within the predicted switching interval, and the switching signal is switched to cause the switching component to be in an off state or in a non-conducting state if the voltage of the first terminal is less than the voltage of the second terminal within the predicted switching interval.

10. The system of claim 9 , wherein the frequency access module obtains the frequency information by zero crossing detection of a voltage or a current of the power generator.

11. The system of claim 9 , wherein the switching interval generation module determines a next switching point as the half period corresponding to the reciprocal of the frequency information away from the switching point.

12. The system of claim 11 , wherein the switching interval generation module forms the predicted switching interval having a second duration of up to the half period corresponding to the reciprocal of the frequency information, and the next switching point is a center of the predicted switching interval.

13. The system of claim 9 , wherein the switching control module receives voltages compared by a comparator between the two terminals of the at least one of the plurality of switching components of the rectifying unit or current direction information determined between the two terminals of the at least one of the plurality of switching components of the rectifying unit within the predicted switching interval in order to switch the switching signal.

14. The system of claim 9 , wherein the control unit further includes a shift calculation module configured for calculating a shift that a time point for switching the switching signal is shifted from a middle point of the predicted switching interval if the time point for switching the switching signal is not at the middle point of the predicted switching interval.

15. The system of claim 14 , wherein the control unit further includes a calibration module configured for calibrating a next time point for switching the switching signal based on the shift, and wherein the next time point for switching the switching signal is at the middle point of a next predicted switching interval.

16. The system of claim 9 , wherein the switching control module is configured for detecting if there is a reverse current after switching the switching signal within the predicted switching interval, and switching the switching signal of the at least one of the plurality of switching components again if there is the reverse current.

17. The system of claim 9 , wherein the plurality of switching components are Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET).

Assignees

• Ind Tech Res Inst

Inventors

• Yeh Po-Ting
• Chang Yuan-Tai
• Juang Kai-Cheung

Classifications

• H02P2101/45

  for motor vehicles, e.g. car alternators · CPC title

• H02J7/1415

  with a generator driven by a prime mover other than the motor of a vehicle · CPC title

• H02M7/162 Primary

  in a bridge configuration · CPC title

• H02M7/219 Primary

  in a bridge configuration · CPC title

• H02P9/48 Primary

  Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle (H02P9/04 - H02P9/46 take precedence) · CPC title