A circuit for combining direct current (DC) power including multiple direct current (DC) voltage inputs; multiple inductive elements. The inductive elements are adapted for operatively connecting respectively to the DC voltage inputs. Multiple switches connect respectively with the inductive elements. A controller is configured to switch the switches periodically at a frequency sufficiently high so that direct currents flowing through the inductive elements are substantially zero. A direct current voltage output is connected across one of the DC voltage inputs and a common reference to both the inputs and the output.

A circuit for combining direct current (DC) power including multiple direct current (DC) voltage inputs; multiple inductive elements. The inductive elements are adapted for operatively connecting respectively to the DC voltage inputs. Multiple switches connect respectively with the inductive elements. A controller is configured to switch the switches periodically at a frequency sufficiently high so that direct currents flowing through the inductive elements are substantially zero. A direct current voltage output is connected across one of the DC voltage inputs and a common reference to both the inputs and the output.

A semiconductor device includes a current control unit whose conductance is variable and a control unit configured to control the conductance of the current control unit. The current control unit is connected to a direct current power source in parallel with a load for the direct current power source, through a capacitor. The control unit sets the current control unit to a first conductance when the direct current power source and the load are not in a conduction state, and sets the current control unit to a second conductance larger than the first conductance when the direct current power source and the load are in the conduction state.

A semiconductor device includes a current control unit whose conductance is variable and a control unit configured to control the conductance of the current control unit. The current control unit is connected to a direct current power source in parallel with a load for the direct current power source, through a capacitor. The control unit sets the current control unit to a first conductance when the direct current power source and the load are not in a conduction state, and sets the current control unit to a second conductance larger than the first conductance when the direct current power source and the load are in the conduction state.

One or more embodiments of the present invention relates to an energy supply circuit for a CT system. The energy supply circuit comprises a stationary energy distribution device, a co-rotating bias voltage supply device, a standard energy supply path having an energy transmission device between the stationary energy distribution device and the co-rotating bias voltage supply device and an alternatively connectable service energy supply path having a voltage protection device. A computed tomography system is also described. Further, a production method for producing an energy supply circuit for a CT system is described. In addition, a method for operating a CT system is described.

The present invention belongs to electric power engineering field, and provides a symmetric method for obtaining line-transferred linear active power flows in Multi-Terminal Direct Current (MTDC) power networks, which comprises: firstly establishing a system of symmetric linear indeterminate equations of buses' injection active powers in terms of buses' voltage offsets; then establishing a symmetric linear matrix equation of buses' voltage offsets in terms of buses' injection active powers and obtaining each bus' voltage offset and bus' voltage of the MTDC power network according to the system of symmetric linear indeterminate equations; finally establishing a symmetric linear relationship that expresses a line-transferred linear active power flow in terms of buses' injection active powers and obtaining each line-transferred linear active power flow of the MTDC power network according to the symmetric linear matrix equation of buses' voltage offsets in terms of buses' injection active powers, known line-transferred non-linear active power flow and inherent operation features of the MTDC power network. The method of the present invention reliably produces accurate results, and not only fast enough for real-time operation regulation of arbitrarily completed MTDC power networks but also applicable for widely varying operation states of them.

The invention concerns a method for managing a system for supplying a vehicle electrical system with electrical energy, comprising the steps consisting of: •supplying the electrical system with electrical energy via the additional electrical energy storage device and the DC/DC converter when the switch is open; •regulating the electrical energy generator to supply voltage lower than that imposed by the DC/DC converter and higher than a voltage of the electrical energy storage device; •closing the switch such that the DC/DC converter imposes a voltage on the electrical system that is higher than that of the electrical energy storage device and the electrical energy generator; •applying a voltage to the electrical system from the electrical energy generator that is higher than that of the DC/DC converter; and deactivating the DC/DC converter.

The invention concerns a method for managing a system for supplying a vehicle electrical system with electrical energy, comprising the steps consisting of: •supplying the electrical system with electrical energy via the additional electrical energy storage device and the DC/DC converter when the switch is open; •regulating the electrical energy generator to supply voltage lower than that imposed by the DC/DC converter and higher than a voltage of the electrical energy storage device; •closing the switch such that the DC/DC converter imposes a voltage on the electrical system that is higher than that of the electrical energy storage device and the electrical energy generator; •applying a voltage to the electrical system from the electrical energy generator that is higher than that of the DC/DC converter; and deactivating the DC/DC converter.

An electrical interconnection circuit can be used with a solid-state-transformer (SST) system. The interconnection circuit includes medium voltage direct current (MVDC) to low voltage direct current (LVDC) direct current to direct current (DC/DC) converters, independent LVDC buses respectively connected to one of the MVDC to LVDC DC/DC converters, and an interconnecting DC/DC converter connecting at least two of the independent LVDC buses in order to ensure equal power demand from each MVDC to LVDC DC/DC converters. The interconnecting DC/DC converter is configured to re-route power between the plurality of independent LVDC buses. A power rating of the interconnecting DC/DC converter is set according to power to be rerouted from other LVDC buses via the interconnecting DC/DC converter.

An electrical interconnection circuit can be used with a solid-state-transformer (SST) system. The interconnection circuit includes medium voltage direct current (MVDC) to low voltage direct current (LVDC) direct current to direct current (DC/DC) converters, independent LVDC buses respectively connected to one of the MVDC to LVDC DC/DC converters, and an interconnecting DC/DC converter connecting at least two of the independent LVDC buses in order to ensure equal power demand from each MVDC to LVDC DC/DC converters. The interconnecting DC/DC converter is configured to re-route power between the plurality of independent LVDC buses. A power rating of the interconnecting DC/DC converter is set according to power to be rerouted from other LVDC buses via the interconnecting DC/DC converter.