Soft-switching power converters using air-core resonant inductor

• US 10,461,651 B2
• Filed: 12/05/2017
• Issued: 10/29/2019
• Est. Priority Date: 12/05/2017
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Schweiz AG (ABB Limited)
• Inventors: Suryanarayana, Harish
• Primary Examiner(s): Berhane, Adolf D
• Assistant Examiner(s): Tiku, Sisay G
• Application Number:
  US15/832,283
• Publication Number:
  US 20190173388A1
• Time in Patent Office: 693 Days
• 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 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33546 with automatic control of the output voltage or current H02M3/33561 takes precedence
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• 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 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/4811 having auxiliary actively switched resonant commutation circuits connected to intermediate DC voltage or between two push-pull branches
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• 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

Unique systems, methods, techniques and apparatuses of a power converter are disclosed. One exemplary embodiment is a resonant power converter comprising a DC bus, a primary leg, an auxiliary leg, and an LC resonant circuit. The auxiliary leg is coupled between DC bus and includes a first auxiliary switch and a second auxiliary switch coupled at an auxiliary midpoint connection. The LC resonant circuit includes an air-core resonant inductor and a resonant capacitor coupled between the auxiliary midpoint connection and a primary midpoint connection of the primary leg. A controller is structured to control the first and second auxiliary switch and the first and second primary switch so as to provide resonant operation of the LC resonant circuit effective to provide a substantially zero voltage condition across the first and second primary switch while toggling the switches.

Claims

1. A resonant power converter comprising:

a DC bus including a first rail and a second rail;

a primary leg coupled between the first rail and the second rail, the primary leg including a first primary switch and a second primary switch coupled at a primary midpoint connection;

an auxiliary leg coupled between the first rail and the second rail, the auxiliary leg including a first auxiliary switch and a second auxiliary switch coupled at an auxiliary midpoint connection, the first auxiliary switch including a wide bandgap semiconductor switch and the second auxiliary switch including a wide bandgap semiconductor switch;

an LC resonant circuit including an air-core resonant inductor and a resonant capacitor coupled between the auxiliary midpoint connection and the primary midpoint connection, the inductance of the LC resonant circuit being less than 400 nH; and

a controller structured to control the first auxiliary switch, the second auxiliary switch, the first primary switch, and the second primary switch so as to provide resonant operation of the LC resonant circuit effective to provide a substantially zero voltage condition across the first primary switch when closing the first primary switch and to provide a substantially zero voltage condition across the second primary switch when closing the second primary switch.

2. The resonant power converter of claim 1 wherein the first auxiliary switch and the second auxiliary switch are gallium nitride semiconductor switches.

3. The resonant power converter of claim 1 wherein the controller is structured to the first auxiliary switch, the second auxiliary switch, the first primary switch, and the second primary switch so as to provide resonant operation of the air-core resonant inductor and resonant capacitor effective to provide a substantially zero current condition across the first auxiliary switch when opening the first auxiliary switch and to provide the substantially zero current condition across the second auxiliary switch when opening the second auxiliary switch.

4. The resonant power converter of claim 1 wherein the primary leg is structured to receive DC power from the first rail and second rail, convert the DC power to AC power, and output the AC power at the primary midpoint connection.

5. The resonant power converter of claim 1 wherein the auxiliary leg and the LC resonant circuit are mounted on a printed circuit board, wherein the air-core resonant inductor is lithographed on the printed circuit board, and wherein the LC resonant circuit includes an output terminal structured to couple the LC resonant circuit to the primary midpoint connection.

6. The resonant power converter of claim 1 wherein the substantially zero voltage condition is a voltage with a magnitude less than 30% of nominal DC voltage.

7. The resonant power converter of claim 1 wherein the auxiliary leg is arranged in a flying capacitor configuration.

8. A resonant circuit structured to be coupled to a non-resonant power converter including a switching device, the resonant circuit comprising:

a first input terminal structured receive power from a DC power source;

a second input terminal structured receive power from the DC power source;

a first DC bus rail coupled to the first input terminal;

a second DC bus rail operatively coupled to the second input terminal;

a leg including a first wide bandgap semiconductor device and a second wide bandgap semiconductor device coupled in series at a midpoint connection;

an LC resonant tank including an air-core resonant inductor and a resonant capacitor, the LC resonant tank being coupled between the midpoint connection and an output port, the LC resonant tank having an inductance less than 400 nH; and

a controller structured to operate the first wide bandgap semiconductor device and the second wide bandgap semiconductor device so as to provide a resonant current to the non-resonant power converter by way of the LC resonant tank effective to provide a substantially zero voltage condition across the switching device when turning the switching device on.

9. The resonant circuit of claim 8 wherein the first wide bandgap semiconductor device and the second wide bandgap semiconductor device include a gallium nitride semiconductor switch.

10. The resonant circuit of claim 8 comprising a second output port coupled to the first DC bus rail and a third output port coupled to the second DC bus rail, wherein the second output port and the third output port are structured to be coupled to the non-resonant power converter.

11. The resonant circuit of claim 8 wherein the resonant circuit includes a printed circuit board coupled to the first input terminal, the second input terminal, the output port, the leg, and the LC resonant tank.

12. The resonant circuit of claim 8 wherein the controller is structured to operate the first wide bandgap semiconductor device and the second wide bandgap semiconductor device so as to provide the resonant current to the non-resonant power converter by way of the LC resonant tank effective to provide a substantially zero current condition through the switching device when turning the switching device off.

13. The resonant circuit of claim 8, wherein the leg includes a third wide bandgap semiconductor device, a fourth wide bandgap semiconductor device, and a flying capacitor, and wherein the leg is arranged in a flying capacitor configuration.

14. A method for operating a bi-level power converter comprising:

operating circuitry including;

an auxiliary circuit including a first wide bandgap switching device and a second wide bandgap switching device coupled at an auxiliary midpoint connection,

a primary circuit including a first primary switching device and a second primary switching device coupled at a primary midpoint connection, and

an LC resonant tank including an air-core resonant inductor and a resonant capacitor coupled between the auxiliary midpoint connection and the primary midpoint connection, the inductance of the LC resonant tank being less than 400 nH;

generating a resonating current using the air-core resonant inductor and the resonant capacitor of the LC resonant tank by operating the auxiliary circuit such that a voltage across the first primary switching device is a substantially zero voltage condition;

opening the first primary switching device; and

closing the second primary switching device in the substantially zero voltage condition.

15. The method of claim 14 comprising coupling an output terminal of the auxiliary circuit to the primary midpoint connection.

16. The method of claim 14 wherein the first wide bandgap switching device and second wide bandgap switching device include a wide bandgap semiconductor device structured to operate at a switching rate greater than 10 kV/ms.

17. The method of claim 14 comprising:

generating a resonating current using the air-core resonant inductor and the resonant capacitor of the LC resonant tank by operating the auxiliary circuit such that a voltage across the second primary switching device is the substantially zero voltage condition;

opening the second primary switching device; and

closing the first primary switching device in the substantially zero voltage condition.

18. The method of claim 14 wherein the auxiliary circuit includes a third wide bandgap switching device, a fourth wide bandgap switching device, and a flying capacitor, wherein the auxiliary circuit is arranged in a flying capacitor configuration.