An apparatus monitoring system stability of a DC power system includes a switching power converter with a control loop. The converter is connected to a DC bus of the system. A monitoring loop injected into the control loop includes a sensor circuit monitoring voltage and current of the DC bus and a small signal injector producing a periodic signal with variable amplitude and frequency and injects the periodic signal on a reference signal of the control loop. The monitoring loop includes a stability measurement circuit that varies a frequency input to the small signal injector until the periodic signal has a frequency equal to a system minor loop gain crossover frequency of an impedance ratio of a converter closed loop output impedance and an impedance of the DC power system. The monitoring loop includes a measurement output circuit that outputs a DC power system stability margin at the crossover frequency.

In accordance with at least one aspect of this disclosure, there is provided a system for aircraft power. The system includes a DC/DC converter having a DC input and a DC output and a switching circuit connecting the DC input to the DC output operable to vary voltage at the DC output. A control module is operatively connected to the switching circuit for variable control of the DC output. The control module includes machine readable instructions to cause the control module to receive input indicative of altitude and control the switching circuit to vary voltage of the DC output as a function of environmental conditions such as altitude and humidity. In embodiments the altitude sensor is operatively connected to the controller.

In accordance with at least one aspect of this disclosure, there is provided a system for aircraft power. The system includes a DC/DC converter having a DC input and a DC output and a switching circuit connecting the DC input to the DC output operable to vary voltage at the DC output. A control module is operatively connected to the switching circuit for variable control of the DC output. The control module includes machine readable instructions to cause the control module to receive input indicative of altitude and control the switching circuit to vary voltage of the DC output as a function of environmental conditions such as altitude and humidity. In embodiments the altitude sensor is operatively connected to the controller.

A DC bus control system for controlling power fluctuations in a DC bus connecting an input power source and a load, comprising: a main stabilization device including a first charging/discharging element and a first power converter; a plurality of the sub stabilization devices including a second charging/discharging element, a charging element, or a discharging element and a second power converter, wherein the plurality of the sub stabilization devices includes a first sub stabilization device having a charging/discharging element and a second power converter and at least one second sub stabilization device having a charging element or a discharging element and a second power converter, and a response speed of the first sub stabilization device is set such that a charging amount of the charging element or a discharging amount of the discharging element of the second sub stabilization device changes with a predetermined time constant.

A power converter may be configured to power multiple output loads, including a main output load and at least one auxiliary output load. The power converter may include control circuitry that controls power delivery to output circuits coupled to the output loads. When the main output load is operating in a reduced power mode, the control circuitry may trigger the switching circuitry to increase the supply of power in order to increase the auxiliary voltages used to power the auxiliary loads if one or more of the auxiliary voltages drops below a threshold due to the main output load operating in the reduced power mode.

An apparatus and method alternately transmit power from a first active power factor corrector (22, 122, 222), receiving power from a first alternating current (AC) source (27), and a second active power factor corrector (24, 124, 224), receiving power from a second AC source (28) having at least one line or neutral in common with the first AC power source (27) and in parallel with the first active power factor corrector (22, 122, 222), to a load (30). Current circulation from the first active power factor corrector (22, 122, 222) to the second active power factor corrector (24, 124, 224) and from the second active power factor corrector (24, 124, 224) to the first active power factor corrector (22, 122, 222) is inhibited.

An operation mode selection unit selects an efficiency priority mode for minimizing the overall loss in a power supply system based on a load request voltage obtained in accordance with the condition of a load and on the conditions of DC power supplies, and generates a mode selection signal in accordance with the selection result. When SOC and/or output power have/has reached power supply restriction values in any DC power supply, an operation mode modification unit generates a final mode selection instructing signal so as to modify selection of the efficiency priority mode by the mode selection signal to select an operation mode in which power distribution between the DC power supplies can be controlled.

Methods, systems, and computer readable media for managing the distribution of photovoltaic power in a multi-floor building are disclosed. According to one aspect, a method includes determining power requirements for each of a plurality of loads associated with a respective plurality of floors in a multi-floor building, wherein each of the plurality of floors includes a direct current (DC) distribution bus. The method further includes using a PV converter to supply a power output from a PV source to one or more of the plurality of loads via one or more respective DC distribution buses, wherein the power output is supplied to the one or more of the plurality of loads in an order such that each subsequent load is supplied at least a remaining portion of the power output after the power requirements of a previously supplied load is fully satisfied.

A computer system at a substation of an electrical grid examines on-grid communication channels and for very channel, the system compares and correlates a GLA signal provided by a downstream transmitter on that channel to a reference GLA signal. The channel that provided the signal with the best correlation is mostly likely the channel with the transmitter. Thus, the feeder and phase of the signal can be determined from the correlation of signals.

A method for controlling energy storage device includes determining whether the operating frequency of the system falls within a dead band range corresponding to a preset frequency range, determining whether an SOC level indicating the charging amount of the energy storage device falls within a preset maintaining range, in a case where the operating frequency falls within the dead band range, and adjusting the SOC level so that the SOC level falls within the maintaining range in a case where the operating frequency of the system falls within the dead band range and the SOC level is outside the preset maintaining range, wherein the maintaining range represents a range between a preset lower limit and a preset upper limit.