IMPROVED SELF POWERED SUPPLY FOR POWER CONVERTER SWITCH DRIVER

• US 20100265740A1
• Filed: 04/15/2009
• Published: 10/21/2010
• Est. Priority Date: 04/15/2009
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Zargari, Navid R., Bortolus, Angelo R., Cheng, George Zhongyuan
• Granted Patent: US 7,965,526 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 1/096 the power supply of the control circuit being connected in parallel to the main switching element H02M1/092 takes precedence
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/348 Passive dissipative snubbers
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver

Abstract

Self-powered supplies with on-board diagnostics are presented for powering a power converter switch driver with power obtained from an associated snubber circuit, including a first converter stage with a full bridge rectifier with a crowbar circuit creating a first DC bus and a second stage with an isolated DC to DC converter, and on-board diagnostics to indicate snubber failures and abnormal conditions of the self-powered supply.

Claims

1. A switch circuit for selectively controlling conduction of current between first and second circuit nodes of a power converter, the switch circuit comprising:

a switching device having first and second switch terminals coupled with the first and second circuit nodes, respectively, or multiple switching devices in a series-connection having the first and last terminals coupled with the first and second circuit nodes respectively, and a control terminal for each switching device receiving a switching signal to selectively operate the switching device in one of a conductive state and a nonconductive state for controlling the conduction of current between first and second circuit nodes;

a switch driver having an output terminal coupled with the control terminal of the switching device and at least one power terminal for receiving power, the switch driver being operative to provide the switching signal according to a received switch control signal using power from the at least one power terminal;

a snubber circuit having a snubber storage device and first and second snubber terminals coupled with anode and cathode nodes of the switching device or switching devices; and

a supply circuit forming a series circuit with the snubber circuit between the cathode and anode nodes in parallel with the switching device or devices, the supply circuit comprising;

a first converter circuit with a full bridge rectifier coupled to the snubber circuit and a supply storage device coupled with a first DC bus created by the rectifier, and

a second converter circuit with an isolated DC to DC converter receiving the first DC bus and providing an isolated main DC output to provide electrical power to the switch driver for operation of the switch driver.

2. The switch circuit of claim 1, wherein the first converter circuit comprises:

a first converter switching device coupled with the full bridge rectifier;

a diode coupled between the first converter switching device and the supply storage device; and

a first converter control circuit operative to control the switching device to regulate the first DC bus.

3. The switch circuit of claim 2, wherein the isolated DC to DC converter of the second converter circuit provides an auxiliary DC output, and wherein the first converter control circuit is powered by the auxiliary DC output.

4. The switch circuit of claim 1, further comprising a diagnostic circuit operatively coupled with the first converter circuit to monitor the first DC bus and with the second converter circuit to monitor the main DC output.

5. The switch circuit of claim 4, wherein the isolated DC to DC converter of the second converter circuit provides an auxiliary DC output, and wherein the diagnostic circuit is powered by the auxiliary DC output.

6. The switch circuit of claim 4, wherein the first converter circuit comprises a shunt coupled with the full bridge rectifier to sense a snubber current and wherein the diagnostic circuit is operatively coupled with shunt to monitor the snubber current.

7. The switch circuit of claim 4, wherein the diagnostic circuit comprises an optical output providing a coded visual indication of at least one fault condition detected by the diagnostic circuit.

8. The switch circuit of claim 4, wherein the diagnostic circuit comprises a diagnostic control output providing a signal indicative of at least one fault condition detected by the diagnostic circuit.

9. The switch circuit of claim 1, wherein the switch driver and the switching device are integrated.

10. The switch circuit of claim 1, wherein the switching device is a gate commutated thyristor (GCT) or symmetric gate commutated thyristor (SGCT) with a gate control terminal receiving the switching signal from the switch driver, and wherein the switch driver and the switching device form an integrated gate commutated thyristor (IGCT).

11. A switch circuit for selectively controlling conduction of current between first and second circuit nodes of a power converter, the switch circuit comprising:

a switching device having first and second switch terminals coupled with the first and second circuit nodes, respectively, or multiple switching devices connected in series with the first and last terminals coupled with the first and second circuit nodes respectively, and a control terminal receiving a switching signal to selectively operate the switching device in one of a conductive state and a nonconductive state for controlling the conduction of current between first and second circuit nodes;

a switch driver having an output terminal coupled with the control terminal of the switching device and at least one power terminal for receiving power, the switch driver being operative to provide the switching signal according to a received switch control signal using power from at least one power terminal;

a snubber circuit having a snubber storage device and first and second snubber terminals with one of the snubber terminals being coupled with an anode node of the switching device; and

a supply circuit forming a series circuit with the snubber circuit in parallel with the switching device, the supply circuit comprising;

a first converter circuit with a rectifier coupled to the snubber circuit and a supply storage device coupled with a first DC bus created by the rectifier,

a second converter circuit with an isolated DC to DC converter receiving the first DC bus and providing an isolated main DC output to provide electrical power to the switch driver for operation of the switch driver, and

a diagnostic circuit operatively coupled with at least one of the first and second converter circuits to monitor at least one condition of the switch circuit.

12. A power conversion system, comprising:

an input for receiving input electrical power;

an output for providing output electrical power;

a switching system comprising a plurality of switch circuits coupled with the input and the output to selectively provide power from the input to the output according to a plurality of switch control signals, the individual switch circuits comprising;

a switching device having first and second switch terminals coupled with the first and second circuit nodes, respectively, or multiple switching devices connected in series with the first and last terminals coupled with the first and second circuit nodes respectively, and a control terminal receiving a switching signal to selectively operate the switching device in one of a conductive state and a nonconductive state for controlling the conduction of current between first and second circuit nodes;

a switch driver having an output terminal coupled with the control terminal of the switching device and at least one power terminal for receiving power, the switch driver being operative to provide the switching signal according to a received switch control signal using power from the at least one power terminal;

a snubber circuit having a snubber storage device and first and second snubber terminals with one of the snubber terminals being coupled with an anode node of the switching device; and

a supply circuit forming a series circuit with the snubber circuit in parallel with the switching device, the supply circuit comprising;

a first converter circuit with a full bridge rectifier coupled to the snubber circuit and a supply storage device coupled with a first DC bus created by the rectifier, and

a second converter circuit with an isolated DC to DC converter receiving the first DC bus and providing an isolated main DC output to provide electrical power to the switch driver for operation of the switch driver.

13. The power conversion system of claim 12, wherein the power conversion system is a current source rectifier receiving AC input power and providing DC output power.

14. The power conversion system of claim 12, wherein the individual first converter circuits comprise:

a first converter switching device coupled with the full bridge rectifier;

a diode coupled between the first converter switching device and the supply storage device; and

a first converter control circuit operative to control the switching device to regulate the first DC bus.

15. The power conversion system of claim 12, the individual switch circuits further comprising a diagnostic circuit operatively coupled with the first converter circuit to monitor the first DC bus and with the second converter circuit to monitor the main DC output.

16. The power conversion system of claim 15, wherein the isolated DC to DC converter of the second converter circuit provides an auxiliary DC output, and wherein the diagnostic circuit is powered by the auxiliary DC output.

17. The power conversion system of claim 15, wherein the first converter circuit comprises a shunt coupled with the full bridge rectifier to sense a snubber current and wherein the diagnostic circuit is operatively coupled with shunt to monitor the snubber current.

18. The power conversion system of claim 15, wherein the diagnostic circuit comprises an optical output providing a coded visual indication of at least one fault condition detected by the diagnostic circuit.

19. The power conversion system of claim 15, wherein the diagnostic circuit comprises a diagnostic control output providing a signal indicative of at least one fault condition detected by the diagnostic circuit.

20. The power conversion system of claim 12, wherein the supply storage device receives charging current from the snubber circuit when a voltage across the first and second switch terminals of the switching device is positive and also receives charging current from the snubber circuit when the voltage across the first and second switch terminals of the switching device is negative.

21. The power conversion system of claim 12, wherein the supply circuit can be set in a test mode automatically by attaching a test cable to test terminals of the switching system, wherein the snubber network and the cathode heatsink are disconnected from the power conversion system when the test cable is connected and utility power is supplied to the power conversion system via the test cable.

22. The power conversion system of claim 12, wherein the supply circuit operates at or close to cathode potential of the switching device.