Method for operating an electrical circuit and electrical circuit
View Patent ↗A method for operating an electrical circuit, in particular of a converter is described. The circuit, in at least one embodiment, includes a line-side converter that is coupled to a capacitor. The line-side converter includes at least two series connections, each including at least two power semiconductor elements, and each of the at least two series connections being connected parallel to the capacitor. The line-side converter is coupled to an energy supply system. The DC voltage that is present at the capacitor is determined. A maximum voltage is predetermined. If the DC voltage present at the capacitor is determined to be greater than the maximum voltage, then at least two of the power semiconductor elements are switched into their conductive state in such a manner that the capacitor is discharged in the direction of the energy supply system.
1. A method for operating an electrical circuit inducing a line-side converter coupled to a capacitor, the line-side converter including at least two series connections, each of the at least two series connections including at least two power semiconductor elements and each of the at least two series connection being connected parallel to the capacitor, the line-side converter being further coupled to an energy supply system, the method comprising:
determining a DC voltage being present at the capacitor;
switching, when the DC voltage is greater than a maximum voltage, at least two of the power semiconductor elements into a conductive state such that the capacitor is discharged in a direction of the energy supply system; and
switching, when the DC voltage equals the maximum voltage, the at least two power semiconductor elements into a non-conductive state such that the capacitor is discharged in a direction of a load.
2. The method of claim 1 , wherein the power semiconductor elements, that are switched into the conductive state, are switched into a non-conductive state when the DC voltage present in the capacitor is determining to be lower than the maximum voltage.
3. The method of claim 1 , wherein the power semiconductor elements are switched into the conductive state such that an electrical connection from a positive potential via the energy supply system to a negative potential is created, wherein the DC voltage present at the capacitor is present between a positive and a negative potential.
4. The method of claim 1 , wherein an upper power semiconductor element of the first series connection and a lower power semiconductor element of the second series connection are switched into their respective conductive states.
5. The method of claim 1 , wherein the maximum voltage is selected such that only when said maximum voltage is exceeded, there may be a possibility that the power semiconductor element is being destroyed when said element is switched from the conductive to the non-conductive state.
6. The method of claim 1 , wherein the power semiconductor elements are switched into the non-conductive state when the maximum voltage is passed.
7. The method of claim 6 , wherein switching of the power semiconductor elements into the non-conductive state is blocked after the maximum voltage is exceeded.
8. An electrical circuit, comprising:
a line-side converter, coupled to a capacitor, including at least two series connections, each of the at least two series connections including at least two power semiconductor elements and each of the at least two series connections being connected to the capacitor in a parallel manner, the line-side converter further being coupled to an energy supply system; and
a control device to determine a DC voltage present at the capacitor, configured to, when the DC voltage is greater than a maximum voltage, switch at least two of the power semiconductor elements into a conductive state such the capacitor is discharged toward the energy supply system;
wherein, when the DC voltage equals the maximum voltage, the control device is configured to switch the at least two power semiconductor elements into a non-conductive state such that the capacitor is discharged in a direction of a load.
9. The method for operating an electrical circuit of claim 1 , wherein the electrical circuit is a converter.
10. The electrical circuit of claim 8 , wherein the electrical circuit is a converter.