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US 2026/0221923 A1Published application
Ac-side active common-mode filter for inverters
OwnerRudolf Haeussermanninventor
Life of this patent
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Abstract
A control device for operating a load by means of pulse-width-modulated voltage signals via a wiring harness comprising two or more drive lines comprises: a signal generator for respectively generating and feeding the pulse-width-modulated voltage signals into a corresponding one of the drive lines, a transformer having a respective winding for each of the drive lines and having a compensation winding, and a controller circuit designed to control a voltage applied to the compensation winding in order to reduce a possible common-mode voltage on the drive lines.
Claims10
1:
- A control device for operating a load by means of pulse-width-modulated voltage signals via a cable harness comprising two or more drive lines, comprising:
- a signal generator which is configured to generate and feed the pulse-width-modulated voltage signals into a corresponding one of the drive lines;
- a transformer with one winding each for each of the drive lines and with a compensation winding;
- a regulator circuit which is configured to regulate a voltage applied to the compensation winding in order to reduce a possible common mode voltage on the drive lines;
- wherein the regulator circuit is configured to capture the voltages of the respective voltage signals currently present on the drive lines between the transformer and the load and to determine an average value from these as a regulating variable for regulating the voltage applied to the compensation winding,
- a low-pass filter unit which is configured to supply the regulator circuit for regulating the voltage applied to the compensation winding with a reference variable obtained from low-pass filtering of a signal, which at least one of:
- corresponds to a common mode voltage of the pulse-width-modulated voltage signals output by the signal generator onto the drive lines, and
- is provided by a microprocessor unit.
5 more elements
2:
- The control device as claimed in claim 1, wherein the regulator circuit comprises a first amplifier, the inputs of which are supplied with at least one of:
- the regulating variable and the reference variable, the output of which is connected, at least one of:
- directly and via a capacitor, to one end of the compensation winding, and the gain of which is set via a resistor which is connected between the input, to which the regulating variable is supplied, and the output.
3:
- The control device as claimed in claim 2, wherein the average value determined as the regulating variable is obtained via a first voltage divider, wherein the corresponding input of the first amplifier is connected to a node which in turn is connected via respective at least one of:
- resistors and capacitors to each of the drive lines between the transformer and the load.
4:
- The control device as claimed in claim 2, further comprising:
- an interference variable feedforward unit which is configured to capture a common mode voltage currently present on the drive lines between the signal generator and the transformer as an interference variable and apply a voltage that counteracts the interference variable via the transformer to the compensation winding.
5:
- The control device as claimed in claim 4, wherein the interference variable feedforward unit has a second amplifier which is operated as an impedance converter and the non-inverting input of which is supplied with, as an interference variable, an average value of the voltages of the respective voltage signals that are currently present on the drive lines between the signal generator and the transformer;
- wherein the output of the amplifier operated as an impedance converter is connected to the other end of the compensation winding.
6:
- The control device as claimed in claim 5, wherein the average value determined as an interference variable is obtained via a second voltage divider, wherein the non-inverting input of the second amplifier operated as an impedance converter is connected to a second node which in turn is connected, via respective at least one of:
- resistors and capacitors, to each of the drive lines between the signal generator and the transformer.
7:
- The control device as claimed in claim 5, wherein the low-pass filter unit is connected on the input side to a third node at the output of the second amplifier operated as an impedance converter and is connected on the output side to a corresponding input of the first amplifier of the regulator circuit in order to supply the captured, inverted and low-pass-filtered interference variable to the regulator circuit as the reference variable.
8:
- The control device as claimed in claim 1, further comprising:
- the microprocessor unit which is connected to the signal generator via a first control output and controls the generation of pulse-width-modulated voltage signals;
- wherein the low-pass filter unit is connected on the input side to the microprocessor unit;
- wherein the microprocessor unit has a second control output and is configured to output a further pulse-width-modulated voltage signal to the low-pass filter unit via the second control output;
- and
- wherein the further pulse-width-modulated voltage signal output via the second control output is generated depending on the pulse-width-modulated voltage signals generated via the first control output in the signal generator.
3 more elements
9:
- The control device as claimed in claim 8, wherein the microprocessor unit has a digital-to-analog converter at the second control output.
10:
- The control device as claimed in claim 1, wherein the low-pass filter unit comprises an RC element.