Suppression of a dc component in a transformer of a voltage converter

Patent metadata

Field	Value
Publication number	US-2017201190-A1
Application number	US-201515314559-A
Country	US
Kind code	A1
Filing date	Apr 9, 2015
Priority date	Jun 2, 2014
Publication date	Jul 13, 2017
Grant date	—

Abstract

The present invention relates to a voltage converter comprising a primary side which has a full bridge device which is configured for the purpose of receiving a first DC voltage from a voltage source at a first amplitude and to transmit same to a primary coil arranged in the primary side, comprising a control unit which is designed for the purpose of controlling the full bridge device using PWM signals having phases shifted counter to one another, wherein the control unit is configured to detect an asymmetry in the current supplied to the primary coil based on a current profile in the primary coil, wherein the control unit is designed to compensate for a detected asymmetry by adjusting the PWM signals. The present invention further relates to a corresponding method.

First claim

1 . A voltage converter ( 1 )
having a primary side ( 2 ) which includes a full-bridge device ( 3 ) which is designed to receive a first DC voltage from a voltage source ( 4 ) having a first amplitude and to route it to a primary coil ( 5 ) arranged in the primary side ( 2 ); including a control device ( 6 ) which is designed to drive the full-bridge device ( 3 ) via PWM signals ( 7 ) having phases which are shifted relative to one another; wherein the control device ( 6 ) is designed to detect an asymmetry in the current ( 8 ) supplied to the primary coil ( 5 ) based on a current profile in the primary coil ( 5 ); wherein the control device ( 6 ) is designed to balance a detected asymmetry via an adjustment of the PWM signals ( 7 ).

2 . The voltage converter as claimed in claim 1 ,
including a measuring transformer ( 9 ) which is arranged in a diagonal branch ( 10 ) of the full-bridge device ( 3 ) and which is coupled to the control device ( 6 ) in order to provide a value of a current ( 8 ) in the primary coil ( 5 ) to the control device ( 6 ).

3 . The voltage converter as claimed in claim 1 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of at least one current value in each case in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ); wherein the control device ( 6 ) is designed to detect the at least one current value within the last 30 percent of the respective interval of the PWM signals ( 7 ).

4 . The voltage converter as claimed in claim 1 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of at least one current value in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is not coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ).

5 . The voltage converter as claimed in claim 3 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of a plurality of current values.

6 . The voltage converter as claimed in claim 3 ,
characterized in that the control device ( 6 ) is designed to detect one current value in each case in two consecutive cycles of the PWM signals ( 7 ), and based on a difference between the current values, to detect the current profile in the primary coil ( 5 ).

7 . A method for controlling a voltage converter ( 1 ) having a primary coil ( 5 ) supplied with a voltage via a full-bridge device ( 3 ), including the steps of:
driving (S 1 ) the full-bridge device ( 3 ) via PWM signals ( 7 ) having phases which are shifted relative to one another; detecting (S 2 ) an asymmetry in the current ( 8 ) supplied to the primary coil ( 5 ) based on a current profile in the primary coil ( 5 ); and balancing (S 3 ) a detected asymmetry via an adjustment of the PWM signals ( 7 ).

8 . The method as claimed in claim 7 ,
wherein the current profile in the primary coil ( 5 ) is detected via the detection of at least one current value in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ), wherein the at least one current value is detected within the last 30 percent; and/or wherein the current profile in the primary coil ( 5 ) is detected via the detection of at least one current value in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is not coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ).

9 . The method as claimed in claim 8 ,
wherein the current profile in the primary coil ( 5 ) is detected during the detection of the current profile in the primary coil ( 5 ) via the detection of a plurality of current values; or wherein at least two current values are detected, and the slope of the current profile in the primary coil ( 5 ) is detected via the differentiation of the at least two current values.

10 . The method as claimed in claim 8 ,
wherein one current value is detected in each case in two consecutive cycles of the PWM signals ( 7 ), and the current profile in the primary coil ( 5 ) is detected based on a difference between the current values; or wherein the difference between current values is detected in multiple consecutive cycles of the PWM signals ( 7 ) by means of a circuit including switched capacitors ( 11 ), wherein the current profile in the primary coil ( 5 ) is detected based on the detected difference.

11 . The voltage converter as claimed in claim 1 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of at least one current value in each case in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ); wherein the control device ( 6 ) is designed to detect the at least one current value within the last 20 percent of the respective interval of the PWM signals ( 7 ).

12 . The voltage converter as claimed in claim 1 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of at least one current value in each case in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ); wherein the control device ( 6 ) is designed to detect the at least one current value within the last 10 percent of the respective interval of the PWM signals ( 7 ).

13 . The voltage converter as claimed in claim 1 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of at least one current value in each case in an interval of the PWM signals ( 7 ) in which the primary coil ( 5 ) is coupled to the voltage source ( 4 ) via the full-bridge device ( 3 ); wherein the control device ( 6 ) is designed to detect the at least one current value in the center of the respective interval of the PWM signals ( 7 ).

14 . The voltage converter as claimed in claim 3 ,
characterized in that that the control device ( 6 ) is designed to detect two current values and to detect the slope of the current profile in the primary coil ( 5 ) via the differentiation of the two current values.

15 . The voltage converter as claimed in claim 3 ,
characterized in that the control device ( 6 ) has a circuit including switched capacitors ( 11 ) which is designed to detect the difference between the current values in two consecutive cycles of the PWM signals ( 7 ), wherein the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) based on the detected difference.

16 . The voltage converter as claimed in claim 13 ,
characterized in that the control device ( 6 ) is designed to detect the current profile in the primary coil ( 5 ) via the detection of a plurality of current values.

17 . The voltage converter as claimed in claim 13 ,
characterized in that the control device ( 6 ) is designed to detect two current values and to detect the slope of the current profile in the primary coil ( 5 ) via the differentiation of the two current values.

18 . The method as claimed in claim 7 ,
wherein the current profile in the primary coil ( 5 ) is detected via the detection of at least one current value in

Assignees

• Bosch Gmbh Robert

Inventors

• Schenk Rene
• Binhack Stephan

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M2001/0009

  Electricity · mapped topic

• H02M7/53871 Primary

  with automatic control of output voltage or current · CPC title

• H02M7/48 Primary

  using discharge tubes with control electrode or semiconductor devices with control electrode · CPC title

• H02M7/4803

  with means for reducing DC component from AC output voltage · CPC title