INPUT RELAY ARCHITECTURE FOR RECTIFYING POWER CONVERTERS AND SUITABLE FOR AC OR DC SOURCE POWER

• US 20130308356A1
• Filed: 03/05/2013
• Published: 11/21/2013
• Est. Priority Date: 04/17/2012
• Status: Active Grant

• Current Assignee: Acleap Power Incorporated
• Original Assignee: General Electric Company
• Inventors: Subramanium, Palanivel, Reddy, Raghothama, Lin, Gary
• Granted Patent: US 9,350,175 B2
• Time in Patent Office: Days
• US Class Current: 363/53
• CPC Class Codes: H02J 2300/10 The dispersed energy generation being of fossil origin, e.g. diesel generators
• CPC Class Codes: H02J 2300/20 The dispersed energy generation being of renewable origin
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• 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
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Power converter circuitry for converting power from a power source of any one of a number of power source types, and in which arcing at relays in the event of a shutdown is avoided. A shunt circuit is provided in inrush and protection circuitry of the power converter, the circuit including a power field-effect transistor and optionally a series-connected relay. The shunt circuit is controlled to divert current from the main relay in the event of a rectifier fault, allowing the main relay to be opened under reduced or zero current. The field-effect transistor of the shunt circuit can then be safely opened, allowing its series relay to be opened under zero current conditions.

Claims

1. A power converter, comprising:

a rectifier;

a protection circuit comprising a first relay, the first relay having a contact path coupled between an input of the power converter via a first node and the rectifier;

a shunt circuit connected to the first node, and comprising a transistor with a conduction path coupled to the first node; and

shunt control circuitry having an output connected to a control terminal of the transistor, the shunt control circuitry set up to turn on the transistor responsive to a fault condition at the rectifier.

2. The power converter of claim 1, wherein the shunt circuit further comprises:

an auxiliary relay having a contact path connected in series with the conduction path of the transistor, and controlled by the shunt control circuitry.

3. The power converter of claim 1, wherein the power converter has first and second input terminals adapted to receive power from a power source, the first input terminal coupled to the first node;

wherein the shunt circuit is connected between the first node and a second node coupled to the second input terminal of the power converter;

wherein the rectifier has first and second rectifier input nodes coupled to the first and second input terminals, the first rectifier input node coupled to the first input terminal via the protection circuit and connected to the second input terminal via the second node.

4. The power converter of claim 3, further comprising:

a fuse connected between the first input terminal and the first node.

5. The power converter of claim 3, wherein the rectifier and the shunt control circuit are both biased to a signal ground;

wherein the rectifier comprises a diode bridge coupled to the first and second rectifier input nodes;

wherein the transistor of the shunt circuit is a field-effect transistor having a gate connected to the output of the shunt control circuit, and a source/drain path coupled between the first node and signal ground.

6. The power converter of claim 5, wherein the shunt circuit further comprises:

an auxiliary relay having a contact path connected in series with the source/drain path of the transistor between the first node and signal ground, the auxiliary relay controlled by the shunt control circuitry.

7. The power converter of claim 1, wherein the power converter has first and second input terminals adapted to receive power from a power source, the first input terminal coupled to the first node;

wherein the rectifier has first and second rectifier input nodes coupled to the first and second input terminals, respectively, the first rectifier input node coupled to the first input terminal via the protection circuit;

and wherein the shunt circuit is connected between the first node and the first rectifier input node, in parallel with the protection circuit.

8. The power converter of claim 7, wherein the transistor of the shunt circuit is a field-effect transistor having a gate connected to the output of the shunt control circuit, and a source/drain path coupled between the first node and signal ground. and wherein the shunt control circuit comprises:

an isolating gate drive circuit, for inductively driving a gate signal applied to the gate of the transistor.

9. The power converter of claim 1, wherein the protection circuit further comprises:

a current limiting device connected in parallel with the contact path of the first relay.

10. The power converter of claim 9, wherein the protection circuit further comprises:

a second relay having a contact path connected in series with the current limiting device.

11. The power converter of claim 1, further comprising:

a DC-DC converter, coupled to outputs of the rectifier, and configured to generate DC power at an output of the power converter.

12. The power converter of claim 1, further comprising:

power type detection circuitry operable to detect a type of power received at the input of the power converter, the power type detection circuitry coupled to the shunt control circuit;

wherein the shunt control circuit is disabled by the power type detection circuitry detecting AC power at the input of the power converter.

13. A power converter configured to receive either an AC or renewable energy source, comprising:

a protection circuit comprising a first relay, the first relay having a contact path coupled between an input of the power converter via a first node and the rectifier;

a shunt circuit connected to the first node;

a shunt control circuitry having an output connected to a control terminal of the transistor, the shunt control circuitry set up to turn on responsive to a fault condition at the power converter;

a power type detection circuitry operable to detect the AC or renewable energy source at the input of the power converter, the power type detection circuitry coupled to the shunt control circuit; and

wherein the shunt control circuitry is disabled by the power type detection circuitry detecting hard DC power above a set-threshold at the input of the power converter, and is enabled by the power type detection circuitry detecting soft DC power below the set-threshold at the input of the power converter.

14. A method of operating a protection circuit in a power converter, comprising:

applying power from a power source to inputs of a power converter;

closing contacts of a first relay in the power converter to communicate the applied power to a rectifier, the contacts of the first relay being in a contact path connected between the rectifier and a first node coupled to a first input of the power converter;

detecting a fault condition at the rectifier;

responsive to the detected fault condition, turning on a shunt circuit connected to the first node to divert current from the contact path of the first relay; and

then opening the contacts of the first relay.

15. The method of claim 14, further comprising:

prior to closing contacts of the first relay, communicating the applied power to the rectifier via a current limiting device coupled between the first node and the rectifier.

16. The method of claim 15, wherein the communicating comprises:

closing contacts of a second relay connected in series with the current limiting device between the first node and the rectifier.

17. The method of claim 16, wherein turning on the shunt circuit comprises:

responsive to the detected fault condition, turning on a transistor having a conduction path coupled to the first node.

18. The method of claim 17, wherein turning on the shunt circuit further comprises:

after turning on the transistor, closing contacts of an auxiliary relay, the contacts in a contact path connected in series with the conduction path of the transistor.

19. The method of claim 17, wherein the shunt circuit is connected between the first node and a second input of the power converter.

20. The method of claim 17, wherein the shunt circuit is connected in parallel with the first relay between the first node and an input of the rectifier.