A voltage conversion apparatus includes connection terminals to which a battery, a capacitor, and a protected load are respectively connected, a first DC-DC converter having input/output terminals, a second DC-DC converter having input/output terminals, a first power path having one end connected to the first connection terminal and the other end connected to the first input/output terminal, a second power path having one end connected to the second input/output terminal and the other end connected to the third input/output terminal, a third power path having one end connected to the fourth input/output terminal and the other end connected to the second connection terminal, and a fourth power path having one end connected to a midway part of the second power path and the other end connected to the third connection terminal.

In an embodiment, an airport electric vehicle charging system includes a current transducer electrically coupled with a power source; a solid state converter electrically coupleable with an aircraft at or near an airport gate and configured to provide and maintain power to the aircraft; and a controller. The system further includes a first feedback loop between the controller and the current transducer; a second feedback loop between the controller and the solid state converter; and a battery charger electrically coupled with the power source and configured to charge one or more electric vehicles. The first feedback loop provides a first feedback signal generated by the current transducer to the controller. The second feedback loop provides a second feedback signal generated by the solid state converter to the controller. The battery charger is configured to consume power from the power source in accordance with the first and second feedback signals.

Provided is a power distribution apparatus that can be shared by vehicles having different configurations related to power supply. The power distribution apparatus distributes power supplied from a battery mounted in a vehicle to a plurality of loads mounted in the vehicle and connected to a power line connected to the battery and a plurality of power lines connected to the plurality of loads, the apparatus including: a first power supply path that is to be electrically connected to the power line connected to the battery and a power line connected to a first system load mounted in the vehicle; and a second power supply path that is not to be connected to the power line connected to the battery, and is to be electrically connected to a power line connected to a second system load mounted in the vehicle.

A wireless power supply system includes: a wireless power transmitting device configured to include a variable resonant circuit having a variable-controllable resonant frequency characteristic, and to transmit electric power wirelessly via the variable resonant circuit; a power transmission control unit configured to variably control the resonant frequency characteristic of the variable resonant circuit; and a plurality of wireless power receiving devices configured to include respective unique resonant circuits having respective unique resonant frequency characteristics which are different to each other, and to wirelessly receive power from the wireless power transmitting device by a magnetic field resonance mode arising as a result of the unique resonant circuit tuning to a resonant frequency of the variable resonant circuit.

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.

The electrical power generation system using renewable energy is particularly adapted to provide electrical power to an independent or remotely situated electrical device such as a street light, emergency call box, or illuminated road sign. The system includes a pivotally mounted venturi with vanes assuring that the venturi is oriented into the prevailing wind. A vertical axis wind turbine is installed in the venturi throat, and drives a shaft extending through the column upon which the venturi is installed to a generator at the base of the column. The venturi and vanes may include photovoltaic cells thereon for further electrical power. The venturi may be heated from a geothermal source, and may include a variable diameter internal wall to adjust the cross-sectional area of the throat of the venturi. The use of functionally graded materials and other phase change materials may also improve the performance of the device.

Disclosed is a power network system etc. which can safely detach a power router whose communication with a control apparatus becomes interrupted, from other power routers and power cells, the power network system including a second control apparatus controlling one of or plural of the power cells, when the second control apparatus detects abnormality in communication between the apparatus itself and the power router, the second control apparatus performs control so as to stop transmission/reception between the power router in which the abnormality is detected and another power router which is connected to the power router, and when the first control apparatus included in the power router detects abnormality in communication between the power router and the second control apparatus, the first control apparatus performs control so as to stop transmission/reception of the power conversion leg connected to the another power router.

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.

An indicator circuit (10) includes a first light emission device (R1 and D1) configured to be driven by a first voltage (Von) to emit light; a second light emission device (R2 and D2) configured to be driven by a second voltage (Vstb) to emit light; and a control device (Q1, D3 and R3) configured to be driven by the first voltage (Von) and the second voltage (Vstb) to allow the first light emission device (R1 and D1) to be driven when the first voltage (Von) is active but the second voltage (Vstb) is not active and not to allow the first light emission device (R1 and D1) to be driven when the first voltage (Von) and the second voltage (Vstb) are active.

A power control method for controlling power of a plurality of power conversion modules that are respectively connected in parallel to a plurality of photovoltaic, includes: sensing a string current value flowing between outermost opposite ends of the plurality of photovoltaic modules, and voltage and current values of each of the photovoltaic modules; changing the string current value and respectively calculating conversion power values of the plurality of power conversion modules per the changed string current value by using the voltage and current values; searching a string current value for a minimum power point tracking control among the changed string current values by using the conversion power values; and controlling the plurality of power conversion modules to track the searched string current value.