Method for protecting at least one consumer against overvoltage tages and device for carrying out the method

• US 20040022002A1
• Filed: 05/30/2003
• Published: 02/05/2004
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: Sew-Eurodrive GmbH & Company KG (BV Beteiligung GmbH & Company KG)
• Original Assignee: Sew-Eurodrive GmbH & Company KG (BV Beteiligung GmbH & Company KG)
• Inventors: Kollar, Hans-Jurgen
• Granted Patent: US 7,057,869 B2
• Time in Patent Office: Days
• US Class Current: 361/105
• CPC Class Codes: H02H 9/041 using a short-circuiting device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

A method and a device for protecting at least one consumer against overvoltages when working with a method for non-contact transmission of electric power from one or more medium-frequency current sources, whose frequencies may have deviations around medium frequency f_M, to the at least one moving consumer via one or more transmission lines and transformer heads, allocated to the consumers, having a downstream matching controller for adjusting the power received from the transmission line; a transmission line is fed from a medium-frequency current source with a medium-frequency current that is constant in its effective value during the power transmission; the respective consumer is supplied with energy by at least one matching controller having at least one feed-in; one or more fed currents are rectified in each instance in a rectifier, smoothed in each instance by a link-circuit reactor and brought together; with the aid of a switch, the link-circuit current, brought together in each instance, is either supplied to a link-circuit capacitor buffering output voltage U₌ of the matching controller, or is shunted upstream of the link-circuit capacitor, depending upon the power demand of the consumers; and the voltage U₌ at at least one link-circuit capacitor is compared to a predefinable value, and if this value is exceeded, an electronic power circuit-breaker is turned on for shunting the link-circuit current.

Claims

1. A method for protecting at least one consumer against overvoltages

when working with a method for the non-contact transmission of electric power from one or more medium-frequency current sources, whose frequencies may have deviations around medium frequency f_M, to the at least one moving consumer via one or more transmission lines and transformer heads, allocated to the consumers, having a downstream matching controller

for adjusting the power received from the transmission line,

a transmission line being supplied from a medium-frequency current source with a medium-frequency current that is constant in its effective value during the power transmission,

the respective consumer being supplied with energy by at least one matching controller having at least one feed-in, one or more fed currents being rectified in each instance in a rectifier, smoothed in each instance by a link-circuit reactor, and brought together to form a link-circuit current,

with the aid of a switch (S, V1), the link-circuit current, brought together in each instance, either being supplied to a link-circuit capacitor buffering output voltage U₌ of the matching controller, or being shunted upstream of the link-circuit capacitor, depending upon the power demand of the consumers,

and the voltage U₌ at at least one link-circuit capacitor being compared to a fixed or predefinable value, and upon exceeding this value, an electronic power circuit-breaker (V4, Thy) being turned on for shunting the link-circuit current.

2. The method as recited in claim 1,

wherein the electronic power circuit-breaker is a thyristor which, after firing, is only blocked after there is a drop below its holding current or upon disappearance of the current shunted through it.

3. The method as recited in at least one of the preceding claims,

wherein the alternating component of the voltage applied at the thyristor does not reach any high critical values of voltage change per time dU/dt such that a firing of the thyristor is triggered because of this alternating component.

4. The method as recited in at least one of the preceding claims,

wherein the current smoothed by the link-circuit reactor does not have any high critical values of current change per time dl/dt, such that a firing of the thyristor is triggered because of this alternating component.

5. The method as recited in at least one of the preceding claims,

wherein the voltage at the switch V1 has an alternating component which is higher than the critical value of the voltage change per time dU/dt that would trigger a firing of the thyristor if this voltage were applied to the thyristor.

6. The method as recited in at least one of the preceding claims,

wherein the alternating component of the voltage applied at the switch V1 is decoupled in such a way that at the thyristor (V4, Thy), the voltage change per time dU/dt reaches no critical values such that a firing of the thyristor (V4, Thy) is triggered.

7. The method as recited in at least one of the preceding claims,

wherein the signal electronics for generating the driving signal for the electronic power circuit-breaker are supplied from the voltage at the link-circuit capacitor.

8. The method as recited in at least one of the preceding claims,

wherein the signal electronics for generating the driving signal for the electronic power circuit-breaker include a positive feedback.

9. A device for carrying out the method as recited in at least one of the preceding claims,

wherein the matching controller includes a circuit for protection against overvoltages at the link-circuit capacitor,

the circuit including at least one electronic power circuit-breaker (V4, Thy), by which, in the conductive state, link-circuit current from the at least one link-circuit reactor is able to be shunted upstream of the link-circuit capacitor and/or upstream of the decoupling diode V2.

10. The device as recited in at least one of the preceding claims,

wherein the at least one link-circuit reactor is connected to the link-circuit capacitor via a diode V2.

11. The device as recited in at least one of the preceding claims,

wherein the electronic power circuit-breaker is a thyristor which, after firing, is only blocked upon disappearance of the current shunted through it.

12. The device as recited in at least one of the preceding claims,

wherein the anode voltage of the thyristor (Thy, V4) corresponds to the maximum from voltage at the link-circuit capacitor and voltage at the switch (S, V1).

13. The device as recited in at least one of the preceding claims,

wherein the anode of the thyristor is connected via a diode V3 to at least one link-circuit reactor.

14. The device as recited in at least one of the preceding claims,

wherein the anode of the thyristor is connected via a resistor R1 to the link-circuit capacitor C6.