Hot Standby Power Supply for a Variable Frequency Drive

A drive system comprising:

• a variable frequency drive for powering an electric motor of a floating vessel, the variable frequency drive comprising:
• a converter having a DC link;
• a controller configured for controlling the variable frequency drive;
• a converter power input configured for supplying electric power to the converter to precharge the DC link;
• and
• a controller power input configured for supplying electric power to the controller of the variable frequency drive;
• and
• a hot standby power supply for the variable frequency drive, the hot standby power supply comprising:
• a power input operable for receiving electric power from a main power supply of the floating vessel;
• a first electric connection configured to supply electric power at a first voltage level to a converter power input of the variable frequency drive;
• a second electric connection configured to supply electric power at a second voltage level to a control power input of the variable frequency drive, wherein the first voltage level is higher than the second voltage level;
• a transformer operable for transforming received electric power to the first voltage level or to the second voltage level;
• an electric power storage unit operable for storing and supplying electric power, the electric power storage unit being electrically connected so as to be operable to supply electric power to both the first electric connection and the second electric connection, the first electric connection or the second electric connection being supplied via the transformer for providing the first voltage level or the second voltage level, respectively;
• and
• a control unit configured to control the hot standby power supply such that in operation, electric power received at the power input is provided to the converter power input and to the control power input of the variable frequency drive via the first electric connection and the second electric connection, and that upon an interruption in the supply with electric power from the main power supply, electric power is supplied from the electric power storage unit to the converter power input and to the control power input of the variable frequency drive via the first electric connection and the second electric connection,
• wherein the first electric connection is electrically connected to the converter power input, and the second electric connection is electrically connected to the controller power input.

A method for operating a hot standby power supply for supplying electric power to a variable frequency drive, the method comprising:

• receiving electric power at a power input of the hot standby power supply from a main power supply;
• providing electric power at a first voltage level to a converter power input of the variable frequency drive via a first electric connection;
• providing electric power at a second voltage level to a controller power input of the variable frequency drive via a second electric connection, wherein the first voltage level is higher than the second voltage level;
• transforming, with a transformer, received electric power to the first voltage level or to the second voltage level;
• providing received electric power to a power storage unit for charging the power storage unit;
• detecting an interruption in the supply with electric power by the main power supply;
• and
• supplying electric power from the power storage unit to the converter power input and to the controller power input of the variable frequency drive via the first electric connection and the second electric connection, the first electric connection and the second electric connection being supplied with the electric power via the transformer for providing the respective first voltage level or second voltage level.