Power conversion system and control method

Patent metadata

Field	Value
Publication number	US-11990835-B2
Application number	US-202117473202-A
Country	US
Kind code	B2
Filing date	Sep 13, 2021
Priority date	Jun 28, 2019
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

A power conversion system includes a first rectifier and a second rectifier. The first rectifier is configured to operate at a first operating frequency. The first rectifier is configured to be connected with a three-phase power source. A first amount of power flows through the first rectifier from the three-phase power source. The second rectifier is configured to operate at a second operating frequency. The second rectifier is configured to be connected in parallel with the first rectifier, and a second amount of power flows through the second rectifier from the three-phase power source. The second operating frequency is higher than the first operating frequency, and the second amount of power is a fraction of the first amount of power.

First claim

What is claimed is:

1. A system comprising:
a first rectifier coupled to a three-phase power source and configured to operate at a first operating frequency, a first amount of power flowing through the first rectifier from the three-phase power source;
a second rectifier coupled to the three-phase power source and configured to operate at a second operating frequency that is higher than the first operating frequency, a second amount of power flowing through the second rectifier from the three-phase power source, the second amount of power being a fraction of the first amount of power; and
an isolated power converter connected to outputs of the first rectifier and the second rectifier.

2. The system of claim 1 , wherein the first rectifier is a three-phase diode rectifier, and the second rectifier is a three-phase power factor correction converter.

3. The system of claim 2 , wherein the three-phase power factor correction converter is a triangular current mode power factor correction converter comprising:
a first inductor connected between a first phase of the three-phase power source and a first switch leg;
a second inductor connected between a second phase of the three-phase power source and a second switch leg; and
a third inductor connected between a third phase of the three-phase power source and a third switch leg, and wherein the first switch leg, the second switch leg and the third switch leg are connected between a first output terminal of the three-phase diode rectifier and a second output terminal of the three-phase diode rectifier.

4. The system of claim 3 , wherein the first inductor, the second inductor and the third inductor are magnetically coupled to each other.

5. The system of claim 3 , further comprising:
an electromagnetic interference (EMI) filter connected between the three-phase power source and the three-phase diode rectifier.

6. The system of claim 3 ,
wherein the isolated power converter is connected to output terminals of the three-phase diode rectifier, and wherein the isolated power converter comprises a primary network, a transformer and a secondary network, and wherein the primary network is a full-bridge inductor-inductor-capacitor (LLC) converter.

7. The system of claim 6 , wherein the secondary network comprises:
a first diode and a second diode connected in series with one another, a common node of the first diode and the second diode connected to a first terminal of a secondary winding of the transformer; and
a third diode and a fifth switch connected in series with one another, a common node of the third diode and the fifth switch connected to a second terminal of the secondary winding of the transformer through a secondary capacitor, wherein the secondary network is configured as a voltage doubler through fixing the fifth switch in an always-on state.

8. The system of claim 6 , wherein the secondary network comprises:
a first switch and a second switch connected in series with one another, a common node of the first switch and the second switch connected to a first terminal of a secondary winding of the transformer; and
a third switch and a fourth switch connected in series with one another, a common node of the third switch and the fourth switch connected to a second terminal of the secondary winding of the transformer through a secondary capacitor, wherein the secondary network is configured as a voltage doubler through fixing the fourth switch in an always-on state.

9. The system of claim 6 , wherein the secondary network comprises:
a first secondary rectifier comprises:
a first diode and a second diode connected in series with one another, a common node of the first diode and the second diode connected to a first terminal of a first secondary winding of the transformer; and
a third diode and a fifth switch connected in series with one another, a common node of the third diode and the fifth switch connected to a second terminal of the first secondary winding of the transformer through a first secondary capacitor; and

a second secondary rectifier comprises:
a first switch and a second switch connected in series with one another, a common node of the first switch and the second switch connected to a first terminal of a second secondary winding of the transformer; and
a third switch and a fourth switch connected in series with one another, a common node of the third switch and the fourth switch connected to a second terminal of the second secondary winding of the transformer through a second secondary capacitor.

10. The system of claim 9 , wherein the first secondary rectifier and the second secondary rectifier are configured as a first voltage doubler and a second voltage doubler, respectively through fixing both of the fourth switch and the fifth switch in an always-on state.

11. The system of claim 1 , wherein the second rectifier is formed by six insulated gate bipolar transistor (IGBT) devices.

12. A method comprising:
detecting an input voltage applied to an isolated power converter connected to outputs of a first power conversion device and a second power conversion device;
transferring a first amount of power from an alternating current (AC) power source to a direct current (DC) load through the first power conversion device configured to operate at a first operating frequency; and
transferring a second amount of power from the AC power source to the DC load through the second power conversion device configured to operate at a second operating frequency that is higher than the first operating frequency, the second amount of power being a fraction of the first amount of power.

13. The method of claim 12 , further comprising:
configuring a switch of a secondary rectifier of the isolated power converter as an always-on switch to configure the secondary rectifier as a voltage doubler if the input voltage applied to the isolated power converter is below a predetermined threshold.

14. The method of claim 13 , wherein the isolated power converter comprises a primary network, a transformer, and the secondary rectifier connected in cascade with one another, and wherein the primary network is a full-bridge inductor-inductor-capacitor (LLC) converter, and the secondary rectifier comprises:
a first diode and a second diode connected in series with one another, a common node of the first diode and the second diode connected to a first terminal of a secondary winding of the transformer; and
a third diode and the switch connected in series with one another, a common node of the third diode and the switch connected to a second terminal of the secondary winding of the transformer through a secondary capacitor.

15. The method of claim 12 , further comprising:
configuring the second power conversion device to operate in a triangular current mode to achieve a unity power factor.

16. The method of claim 12 , wherein the first power conversion device is a three-phase diode rectifier, and the second power conversion device is a three-phase power factor correction device.

17. A system comprising:
a first power conversion device connected between a three-phase power source and a DC voltage bus and configured to operate at a first operating frequency, a first amount of power flowing from the three-phase power source to the DC voltage bus through the first power conversion device;
a second power conversion device connected between the three-phase power source and the DC voltage bus and configured to operate at a second operating frequency that is higher than the first operating frequency, a second amount of power flowing fr

Assignees

• Huawei Digital Power Tech Co Ltd

Inventors

• Fu Dianbo
• Dai Heping

Classifications

• H02M1/4216 Primary

  operating from a three-phase input voltage (H02M1/4233 takes precedence) · CPC title

• H02M1/4208

  Arrangements for improving power factor of AC input · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title

• H02M3/335

  using semiconductor devices only · CPC title

• H02M7/06

  using discharge tubes without control electrode or semiconductor devices without control electrode · CPC title