Method in frequency converter, and frequency converter

• US 20110141787A1
• Filed: 12/13/2006
• Published: 06/16/2011
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: ABB Beijing Drive Systems Co., Ltd. (ABB Limited)
• Original Assignee: Abb Oy (ABB Limited)
• Inventors: Tiihonen, Vesa, Hedemäki, Ari
• Granted Patent: US 8,238,131 B2
• Time in Patent Office: Days
• US Class Current: 363/159
• CPC Class Codes: H02H 7/1216 for AC-AC converters
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H03K 17/0828 in composite switches
• CPC Class Codes: H03K 2017/0806 against excessive temperature

Abstract

A method in connection with a frequency converter and a frequency converter, the frequency converter being arranged for periodic recurrent use. The method comprises steps for generating and storing in a memory an average heating of a power semiconductor of the frequency converter, caused by one loading period, determining a temperature limit from the generated heating and the highest allowed temperature of the power semiconductor, determining the temperature of the power semiconductor in the frequency converter, and changing the operation mode of the frequency converter when the temperature of the power semiconductor exceeds the temperature limit when transferring to a loading period.

Claims

1. A method in connection with a frequency converter, the frequency converter being arranged for periodic recurrent use, wherein the method comprises steps for generating and storing in a memory an average heating of a power semiconductor in the frequency converter, caused by one loading period, determining a temperature limit from the generated heating and the highest allowed temperature of the power semiconductor, determining the temperature of the power semiconductor in the frequency converter, and changing the operation mode of the frequency converter when the temperature of the power semiconductor exceeds the temperature limit when transferring to a loading period.

2. A method as claimed in claim 1, wherein the average heating caused by one loading period is provided as a parameter to the frequency converter and stored in the memory of the frequency converter.

3. A method as claimed in claim 1, wherein determining the magnitude of the average heating caused by one loading period comprises steps for determining the magnitude of the temperature before the start of the loading period, determining the magnitude of the temperature after the loading period, calculating the difference of the temperatures, repeating and calculating the mean of the differences.

4. A method as claimed in claim 3, wherein the mean of the differences between the starting temperatures and the end temperatures is calculated as an arithmetic mean.

5. A method as claimed in claim 3, wherein the mean of the differences between the starting temperatures and the end temperatures is calculated as a root-mean-square value.

6. A method as claimed in claim 1, wherein determining the temperature limit from the generated heating and from the highest allowed temperature of the power semiconductor comprises the step for reducing the heating generated from the highest allowed temperature of the power semiconductor in order to provide the temperature limit.

7. A method as claimed in claim 1, wherein determining the temperature limit from the generated heating and from the highest allowed temperature of the power semiconductor comprises a step for reducing the sum of the heating generated from the highest allowed temperature of the power semiconductor and the safety margin in order to provide the temperature limit.

8. A method as claimed in claim 1, wherein determining the temperature of the power semiconductor in the frequency converter comprises steps for measuring the temperature of the cooling plate of the power semiconductor and calculating the temperature of the power semiconductor from the temperature of the cooling plate.

9. A method as claimed in claim 1, wherein changing the operation mode of the frequency converter comprises a step for preventing the use of the frequency converter.

10. A method as claimed in claim 1, wherein changing the operation mode of the frequency converter comprises a step for slowing the performance of an operation to be controlled by the frequency converter in order to reduce the temperature change.

11. A method as claimed in claim 1, wherein the method also comprises a step for observing the working condition of the cooling system of the semiconductor component in the frequency converter by comparing the temperature change of the cooling plate to the previously implemented temperature changes or to the temperature change to be calculated from a temperature model.

12. A method as claimed in claim 11, wherein the method further comprises a step for providing an alarm signal in response to the weakening of the working condition of the cooling system.

13. A frequency converter comprising several semiconductors and being arranged for periodic recurrent use, wherein the frequency converter comprises means for generating and storing an average heating of a power semiconductor in the frequency converter, caused by one loading period, means for determining a temperature limit from the generated heating and the highest allowed temperature of the power semiconductor, means for determining the temperature of the power semiconductor in the frequency converter, and means for changing the operation mode of the frequency converter when the temperature of the power semiconductor exceeds the temperature limit when transferring to a loading period.