Patent ID: 8717047
Filing Date: 2014-05-06
Classification: G01R

Abstract:
1. An electric circuitry, comprising an inverter configured to feed an output of a photovoltaic generator into an alternating voltage mains; a grounding device configured to ground the photovoltaic generator at a positive pole or at a negative pole thereof when the photovoltaic generator is coupled to the inverter; a first shunt through which a first current flows in case of a short-to-ground when the photovoltaic generator is grounded at the positive pole; a second shunt through which a second current flows in case of a short-to-ground when the photovoltaic generator is grounded at the negative pole; wherein the first shunt and the second shunt reside in a first current mirror circuit and a second current mirror circuit, respectively, each of the first current mirror circuit and the second current mirror circuit comprising a first transistor connected to a first terminal of the respective first shunt and second shunt through a first series-connected resistor, and a second transistor connected to a second terminal of the respective first shunt and second shunt through a second series-connected resistor which has the same resistance as the first series-connected resistor, and wherein the first current mirror circuit and the second current mirrors circuit are connected to each other at a point of evaluation; wherein a voltage drop caused in the respective first shunt and second shunt by the respective first current and second current flowing in case of a short-to-ground generates an asymmetry in the respective first mirror circuit and second current mirror circuit, a magnitude of which is proportional to the respective first current and second current flowing through the respective first shunt and second shunt, and wherein the asymmetry is evaluated at the point of evaluation at which the first current mirror circuit and second current mirror circuit are connected to each other, wherein a potential at the point of evaluation differs from a potential at which the current flows through the respective first shunt and second shunt in case of a short-to-ground.