A method for determining parameters for controlling N electric generators at an instant t, the method including, for a required power P.sub.tot(t)=Σ.sub.i=1.sup.NP.sub.i(t) at an instant t with P.sub.i(t) the electric power supplied by the electric generator i at the instant t and a reserve power P.sub.reserve(t)≤Σ.sub.i=1.sup.N(P.sub.i.sup.max−P.sub.i(t)×δ.sub.i(t) at an instant t with P.sub.i.sup.max the maximum power that the electric generator i can develop and δ.sub.i(t) the coefficient of activation of the electric generator i which is equal to 1 when the electric generator is on and 0 when the electric generator is off, a step of determining the optimal power P.sub.i.sup.opt(t) at the instant t associated with each electric generator i so as to minimise the fuel consumption per unit of electrical energy produced $\mathrm{sfc}\left(t\right)=\frac{1}{P_{\mathrm{tot}}\left(t\right)}\underset{i=1}{\overset{N}{.Math.}}{f}_i\left(P_i\left(t\right)\right)\times P_i\left(t\right)$
with f.sub.i(x) the function giving the fuel consumption of the electric generator i for the electric power x.

Quickly USB Charging ports for lighting device has USB charging-ports which meet 2007 released specification has minimum 1.0 Amp to 5 Amp at DC 5 Volt safety and quickly charging capacity to quickly charge DC current into energy-storage unit or assembly inside the other electric or digital product(s) without high voltage DC current for overheat and fire risk and, optionally, additional outlet-units, to supply AC current to other electric or digital devices including smart phone, computer, communication, consumer electric products. The USB-unit(s) or USB-Module(s) or Outlet-unit(s) fit within or install on anywhere of the item's housing including anywhere of the base, pole, bar, stand, step, contour, edge, walls. The said USB charger only has charging function no any data transmit and only have one input power source not more than one and charging capacity minimum 1.0 Amp up for quickly charge from USB-Charging-ports by 2 male USB-plugs' USB-wire to the device's female USB-ports. The device has 2.sup.nd or more circuit-inside of device's housing to supply the current to other functions including other light source, LEDs, Plurality of LEDs has different colors, controller, switch, sensor, motion sensor, PIR, remote controller, IP cam and related IR photo-diode or wireless communication for big current needed which may use 2.sup.nd transformer to supply big Amperage and different working voltage to prevent from 1 transformer not only supply USB Charging-ports(s) but also Big Power consumption for LEDs or other light source or other functions need power.

Quickly USB Charging ports for lighting device has USB charging-ports which meet 2007 released specification has minimum 1.0 Amp to 5 Amp at DC 5 Volt safety and quickly charging capacity to quickly charge DC current into energy-storage unit or assembly inside the other electric or digital product(s) without high voltage DC current for overheat and fire risk and, optionally, additional outlet-units, to supply AC current to other electric or digital devices including smart phone, computer, communication, consumer electric products. The USB-unit(s) or USB-Module(s) or Outlet-unit(s) fit within or install on anywhere of the item's housing including anywhere of the base, pole, bar, stand, step, contour, edge, walls. The said USB charger only has charging function no any data transmit and only have one input power source not more than one and charging capacity minimum 1.0 Amp up for quickly charge from USB-Charging-ports by 2 male USB-plugs' USB-wire to the device's female USB-ports. The device has 2.sup.nd or more circuit-inside of device's housing to supply the current to other functions including other light source, LEDs, Plurality of LEDs has different colors, controller, switch, sensor, motion sensor, PIR, remote controller, IP cam and related IR photo-diode or wireless communication for big current needed which may use 2.sup.nd transformer to supply big Amperage and different working voltage to prevent from 1 transformer not only supply USB Charging-ports(s) but also Big Power consumption for LEDs or other light source or other functions need power.

The light device has USB charger has AC outlet power source has though the AC-to-DC device to change from 1.sup.st Alternative current to 1.sup.st voltage Direct current and the 1.sup.st voltage DC current though the circuit-inside or IC or DC-to-DC circuit to get 2.sup.nd voltage or though more DC-to-DC devices to get more voltage DC current. The light device has At least one of voltage DC current to supply to USB Charger Charging-port output-end at 5 Volt and one of desire voltage DC current to supply to DC light source. Or/The 1.sup.st AC current to AC light source and has one of DC current selected from 1.sup.st, 2.sup.nd or more voltage DC current to USB Charger charging-port's output end so the said light device has (1) illumination function by DC or/and AC light source and (2) USB charger function by supply desired 1.sup.st or 2.sup.nd or more other voltage DC current to USB charging-port at 5 Volt DC. The light device optional has outlet-ports to get 1.sup.st AC directly though conductive parts to outlet-ports to supply AC to other device. Furthermore, the light device Optional can add other function(s) select from (a) Time piece related (b) Reflect Image (c) Power station (d) project image (e) heater (f) Air Flow (g) wireless communication (h) remote controller (g) APP controller (h) Blue-tooth controller.

The light device has USB charger has AC outlet power source has though the AC-to-DC device to change from 1.sup.st Alternative current to 1.sup.st voltage Direct current and the 1.sup.st voltage DC current though the circuit-inside or IC or DC-to-DC circuit to get 2.sup.nd voltage or though more DC-to-DC devices to get more voltage DC current. The light device has At least one of voltage DC current to supply to USB Charger Charging-port output-end at 5 Volt and one of desire voltage DC current to supply to DC light source. Or/The 1.sup.st AC current to AC light source and has one of DC current selected from 1.sup.st, 2.sup.nd or more voltage DC current to USB Charger charging-port's output end so the said light device has (1) illumination function by DC or/and AC light source and (2) USB charger function by supply desired 1.sup.st or 2.sup.nd or more other voltage DC current to USB charging-port at 5 Volt DC. The light device optional has outlet-ports to get 1.sup.st AC directly though conductive parts to outlet-ports to supply AC to other device. Furthermore, the light device Optional can add other function(s) select from (a) Time piece related (b) Reflect Image (c) Power station (d) project image (e) heater (f) Air Flow (g) wireless communication (h) remote controller (g) APP controller (h) Blue-tooth controller.

A safe energy supply unit (1) and system, for supplying an electrical device (8) in an explosion-proof area, transmits power from an energy source (9), including a plurality of galvanically isolated individual sources, with a multiple line connection (2) with a plurality of galvanically isolated and individually shielded conductor pairs (31, 32, 33, 34). A collector device (4), in an explosion-proof jacket (5) at an end of the multiple line (3), has uncoupling devices (45) for the galvanically isolated conductor pairs and a combiner circuit (47, 49) that combines the transmitted electric power from each line into a global power. The global power is outputted at an output (48) of the collector device to the electrical device. The conductor pairs allow for an increased global power, which is scalable, safely transmittable, with standard, conductor pairs. The electrical device is intrinsically safely supplied with high power with minimal effort.

A method of preserving power quality on a power grid is provided. The method is implemented by a voltage overflow device that is electrically coupled to the power grid through electrical contacts. A voltage monitoring circuit of the voltage overflow device monitors a voltage via the electrical contacts on the power grid with respect to a predetermined voltage. The voltage monitoring circuit determines whether the voltage exceeds the predetermined voltage. A switch of the voltage overflow device shunt an excess voltage over the predetermined voltage to a resistive load when the voltage exceeds the predetermined voltage to preserve the power quality on the power grid.

A method of preserving power quality on a power grid is provided. The method is implemented by a voltage overflow device that is electrically coupled to the power grid through electrical contacts. A voltage monitoring circuit of the voltage overflow device monitors a voltage via the electrical contacts on the power grid with respect to a predetermined voltage. The voltage monitoring circuit determines whether the voltage exceeds the predetermined voltage. A switch of the voltage overflow device shunt an excess voltage over the predetermined voltage to a resistive load when the voltage exceeds the predetermined voltage to preserve the power quality on the power grid.

In some examples, an electrical power system includes a differential bus, a power converter coupled to the differential bus, and a controller configured to control the power converter based on a first target value for the differential bus. The controller is also configured to sense that a ground fault has occurred in the electrical power system while controlling the power converter based on the first target value. The controller is further configured to, responsive to sensing that the ground fault has occurred, control the power converter based on a second target value for the differential bus, the second target value being different than the first target value.

The present invention provides a novel power distribution harness system provided as a unit for distribution of power from a primary power source.