Voltage converting system and method of using the same

• US 10,476,395 B2
• Filed: 11/30/2017
• Issued: 11/12/2019
• Est. Priority Date: 11/30/2017
• Status: Active Grant

• Current Assignee: Huawei Digital Power Technologies Company Limited (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Dai, Heping
• Primary Examiner(s): Ahmed, Yusef A
• Application Number:
  US15/827,508
• Publication Number:
  US 20190165665A1
• Time in Patent Office: 712 Days
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/0845 digitally controlled (or with digital control)
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33584 Bidirectional converters
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• 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

Aspects of the disclosure provide a voltage converting system. The voltage converting system includes a first power converter configured to convert an input voltage to an intermediate voltage, a second power converter configured to convert the intermediate voltage to an output voltage at a target voltage level, and a control circuit coupled to the first power converter and the second power converter. The control circuit is configured to, upon detection of the input voltage having a voltage level that is within a first range, perform a close-loop control of the second power converter to output the output voltage at the target voltage level.

Claims

1. A voltage converting system, comprising:

a first power converter configured to convert an input voltage to an intermediate voltage, wherein the first power converter is a buck-boost converter;

a second power converter configured to convert the intermediate voltage to an output voltage at a target voltage level, wherein the second power converter is an isolated direct current (DC) to DC converter; and

a control circuit coupled to the first power converter and the second power converter that is configured to;

perform a first close-loop control on the first power converter and a second open-loop control on the second power converter when the input voltage is over a first threshold or below a second threshold, and perform a first open-loop control on the first power converter and a second close-loop control on the second power converter when the input voltage is between the second threshold and the first threshold, wherein the first threshold is higher than the second threshold, and wherein under the first open-loop control, the input voltage applied to the first power converter is passed to an output node of the first power converter through an inductive device.

2. The voltage converting system according to claim 1, wherein the control circuit is configured to perform the first close-loop control of the first power converter using the output voltage as a feedback.

3. The voltage converting system according to claim 1, wherein the control circuit is configured to perform the first close-loop control of the first power converter using the intermediate voltage as a feedback.

4. The voltage converting system according to claim 1, wherein

the second power converter includes an inverter, a rectifier, and a transformer between the inverter and the rectifier.

5. The voltage converting system according to claim 4, wherein

the inverter of the second power converter comprises:

a first half-bridge leg having a first power node configured to receive the intermediate voltage from the first power converter; and

a second half-bridge leg having a second power node configured to receive the intermediate voltage from the first power converter, and

the transformer of the second power converter comprises a primary side electrically coupled between output nodes of the first half-bridge leg and the second half-bridge leg.

6. The voltage converting system according to claim 4, wherein

the inverter of the second power converter comprises:

a first half-bridge leg having a first power node configured to receive the intermediate voltage from the first power converter; and

a second half-bridge leg having a second power node configured to receive the input voltage, and

the transformer of the second power converter comprises a primary side electrically coupled between output nodes of the first half-bridge leg and the second half-bridge leg.

7. The voltage converting system according to claim 1, wherein

the first power converter, under the first close-loop control, is configured to receive the input voltage within a first dynamic range,

the second power converter, under the second close-loop control, is configured to receive the intermediate voltage within a second dynamic range, and

the second dynamic range is greater than the first dynamic range.

8. A method, comprising:

driving a first power converter of a voltage converting system to convert an input voltage to an intermediate voltage, wherein the first power converter is a buck-boost converter; and

driving a second power converter of the voltage converting system to convert the intermediate voltage to an output voltage at a target voltage level based on a voltage level of the input voltage, including;

performing a first close-loop control on the first power converter and a second open-loop control on the second power converter when the input voltage is over a first threshold or below a second threshold, and performing a first open-loop control on the first power converter and a second close-loop control on the second power converter when the input voltage is between the second threshold and the first threshold, wherein the first threshold is higher than the second threshold, wherein under the first open-loop control, the input voltage applied to the first power converter is passed to an output node of the first power converter through an inductive device, wherein the second power converter is an isolated converter.

9. The method according to claim 8, wherein the performing the first close-loop control on the first power converter comprises using the output voltage as a feedback.

10. The method according to claim 8, wherein the performing the first close-loop control on the first power converter comprises using the intermediate voltage as a feedback.