Battery charging device and method of controlling a battery charging device

A battery charging device connectable to a power grid, comprising:

• a power outlet provided with a first, a second, a third, and a fourth terminal;
• a plurality of voltage sensors associated with a first, a second, a third, and a fourth node connected to said first, said second, said third, and said fourth terminal, respectively, and configured to generate a first, a second, a third, and a fourth voltage signal, each representing a voltage value at the respective node;
• a processing unit configured for:
• receiving said first, second, third and fourth voltage signals;
• processing said voltage signals so as to extract, for each of said first, second, third and fourth signal, a first and a second value representing a module and a phase shift of the voltage flowing in the respective node;
• comparing said first and second values with respective reference values representing modules, phase shifts, and natural frequencies of a plurality of types of power grids;
• based on said comparison, determining a type of power grid to which the battery charging device is connected, selecting a type of power grid to which said first and second values correspond;
• and
• configuring a topology of the charging device and/or monitoring a state of connection of the device to the power grid according to the type of power grid determined,
• wherein said processing unit is also configured for:
• based on said comparison, identifying which of the first, second, third and fourth nodes is a neutral node connected to a neutral of the power grid;
• monitoring the first value of the voltage signal at said neutral node;
• comparing said first value with the corresponding reference value of the type of grid determined;
• identifying an earth disconnection or earthing degradation condition when a difference between the first value of the voltage signal at the neutral node and the corresponding reference value exceeds a predetermined threshold value;
• and
• generating an alarm signal in response to the identification of said earth disconnection or earthing degradation condition.

A method of controlling a battery charging device connected to a power grid by means of a power outlet, the method comprising:

• detecting a first, a second, a third, and a fourth voltage signal at a first, a second, a third, and a fourth node associated with respective terminals of the power outlet and representing three phase nodes and a neutral node;
• processing said voltage signals so as to extract, for each signal, a first and a second value representing a module and a phase shift of the voltage flowing in the respective phase or neutral node;
• comparing said first and second values with respective reference values representing the modules, phase shifts, and natural frequencies of a plurality of types of electrical networks;
• based on said comparison, determining the type of power grid to which the battery charging device is connected, selecting the type of grid to which said first and second values correspond;
• controlling the charging device by adapting it to the type of power grid determined, based on said comparison, identifying which of the first, second, third and fourth nodes is a neutral node connected to the neutral of the power grid;
• monitoring the first value of the voltage signal at said neutral node;
• comparing said first value with the corresponding reference value;
• identifying an earth disconnection or earthing degradation condition when a difference between the first value of the voltage signal at the neutral node and the corresponding reference value exceeds a predetermined threshold value;
• generating an alarm signal in response to the identification of said earth disconnection or earthing degradation condition.