Abstract: A direct current (DC) microgrid is provided. The microgrid includes a power converter, a power-voltage (PV) droop control loop, and an inner current control loop of the power converter. The PV droop control loop is configured to receive measurements of a droop current quantity that is not a DC bus current of the DC microgrid. The droop current quantity is used to determine a droop power quantity selected as a power quantity in a PV relationship. The PV droop control loop is further configured to derive a current reference based on droop in the droop power quantity. The inner current control loop is configured to control operation of the power converter by deriving a measured current corresponding to the control quantity based on the measurements of the droop current quantity, directly comparing the current reference with the measured current, and generating switching signals of switches in the power converter.

Abstract: A preparation method of lawn bricks capable of solidifying and stabilizing lead-contaminated soil includes: preparing carbonized bagasse, grinding and mixing the carbonized bagasse and potassium carbonate in a mortar, heating the resulting mixture to 600-650° C., and maintaining for 2-3 hours; fully mixing the carbonized and treated bagasse, heavily-lead-contaminated soil, construction waste and fly ash; then adding a treated sodium silicate solution and stirring, and reacting under ultrasonic conditions; and performing grouting and compacting to obtain a homogeneous green brick, and curing same to obtain a lawn brick. The bagasse is taken as a raw material, and is carbonized and then mixed with the pre-treated heavily-Pb-contaminated soil, construction waste and fly ash, and under an action of alkali excitation and ultrasonic assistance, the resulting mixture is cured to form the lawn brick, such that Pb (II) in the Pb-contaminated soil is not migrated and converted any more.

Abstract: A system for synchronously recovering nitrogen and carbon dioxide from boiler flue gas includes: a flue gas pretreatment system used for dehydrating and cooling boiler flue gas; a carbon and nitrogen separation system communicated with the flue gas pretreatment system, and used for performing pressure swing adsorption on the pretreated flue gas and separating the nitrogen-containing vent gas and the crude carbon dioxide gas; a carbon dioxide secondary purification system communicated with the carbon and nitrogen separation system, and used for performing secondary purification on the crude carbon dioxide gas separated from the carbon and nitrogen separation system; and a nitrogen concentration and purification system communicated with the carbon and nitrogen separation system and the carbon dioxide secondary purification system, and used for purifying the nitrogen-containing vent gas separated from the carbon and nitrogen separation system and the vent gas generated by the carbon dioxide secondary purificatio

Abstract: The disclosure are a natural environment accelerated corrosion test device and method for air conditioners. The natural environment accelerated corrosion test device for air conditioners, characterized by comprising a base, a rotating power unit, a rotating frame, an air flow acceleration module, a sample surface temperature rise module, a fluid atomization spray module, a service environment monitoring module, and a control system. The disclosure can accelerate the corrosion of the outdoor unit of the tested air conditioner without affecting the normal installation and operation of the outdoor unit in the tested natural environment, and without hindering the influence of the environmental conditions of the tested natural environment on the outdoor unit.

Abstract: A direct current (DC) microgrid is provided. The microgrid includes a power converter, a power-voltage (PV) droop control loop, and an inner current control loop of the power converter. The PV droop control loop is configured to receive measurements of a droop current quantity that is not a DC bus current of the DC microgrid. The droop current quantity is used to determine a droop power quantity selected as a power quantity in a PV relationship. The PV droop control loop is further configured to derive a current reference based on droop in the droop power quantity. The inner current control loop is configured to control operation of the power converter by deriving a measured current corresponding to the control quantity based on the measurements of the droop current quantity, directly comparing the current reference with the measured current, and generating switching signals of switches in the power converter.

Abstract: A finite element simulation technology-based atmospheric-corrosion prediction method for an air-conditioner heat exchanger is provided. In the method, a material corrosion prediction model for the material of a heat conduction pipe of an air-conditioner heat exchanger to be tested and the material of heat dissipation fins of said air-conditioner heat exchanger is debugged by means of step S1 and step S2; an assembly corrosion prediction model is then optimized by means of step S3 and step S4; and when a multi-physics field in an air-conditioner serving environment is comprehensively simulated and coupled by using a working condition environment field, the atmospheric corrosion of said air-conditioner heat exchanger after operating in an outdoor serving environment to be tested under a working condition for any preset duration is finally predicted by means of step S5 and step S6, such that an atmospheric-corrosion prediction result is obtained.

Abstract: Methods for separating and recovering Mn, Co, and Ni from leach solutions include selectively recovering and producing high purity products of Mn, Co, and Ni from leach solutions, combining staged precipitation, sulfide precipitation, and solvent extraction to separate contaminants from the leach solution to isolate and recover Mn, Co, and Ni in high yield and purity.

Abstract: In one aspect, a fuel cell power system is provided. The fuel cell power system includes a ring bus, a plurality of bidirectional uninterruptible power supplies (UPSs), a plurality of direct current (DC) fuel cell modules, and a plurality of bidirectional direct current to alternating current (DC-AC) power converters. Each of the plurality of UPSs is electrically coupled to at least one battery, an AC utility feed, a load, and via a choke, the ring bus. Each of the plurality of DC fuel cell modules includes one or more fuel cells coupled to a hydrogen storage. Each of the plurality of bidirectional DC-AC power converters is electrically coupled to a corresponding one of the plurality of DC fuel cell modules and a corresponding one of the plurality of bidirectional UPSs at the AC utility feed.

Abstract: In one aspect, a fuel cell power system is provided. The fuel cell power system includes a ring bus, a plurality of bidirectional uninterruptible power supplies (UPSs), a plurality of direct current (DC) fuel cell modules, and a plurality of bidirectional direct current to alternating current (DC-AC) power converters. Each of the plurality of UPSs is electrically coupled to at least one battery, an AC utility feed, a load, and via a choke, the ring bus. Each of the plurality of DC fuel cell modules includes one or more fuel cells coupled to a hydrogen storage. Each of the plurality of bidirectional DC-AC power converters is electrically coupled to a corresponding one of the plurality of DC fuel cell modules and a corresponding one of the plurality of bidirectional UPSs at the AC utility feed.

Abstract: A system includes: a ring bus; a plurality of static uninterruptible power supplies (UPSs), each static UPS of the plurality of static UPSs including: at least one battery; an input that is electrically connected to a first external electrical power source; and an output that is electrically connected to a load, and, via a first corresponding choke, to the ring bus; at least one fuel-cell interface converter (FIC) that converts direct current (DC) electrical power to alternating current (AC) electrical power, each FIC of the at least one FIC being electrically connected to the ring bus via a second corresponding choke; and a fuel cell module corresponding to and electrically connected to each FIC, the fuel cell module including a fuel cell.

Abstract: In one aspect, a hybrid circuit protection device for current-limiting a fault current between a source and a load during a fault is provided. The hybrid circuit protection device includes an input configured to couple to the source, an output configured to couple to the load, a return configured to couple the source to the load, a main switch configured to selectively couple the input to the output, a switching network coupled in parallel with the main switch, and a controller. The controller is configured to determine that the main switch has opened in response to the fault current, where the fault current has an initial value, and activate the switching network to current-limit the fault current to less than the initial value during the fault.

Abstract: A system for synchronously recovering nitrogen and carbon dioxide from boiler flue gas includes: a flue gas pretreatment system used for dehydrating and cooling boiler flue gas; a carbon and nitrogen separation system communicated with the flue gas pretreatment system, and used for performing pressure swing adsorption on the pretreated flue gas and separating the nitrogen-containing vent gas and the crude carbon dioxide gas; a carbon dioxide secondary purification system communicated with the carbon and nitrogen separation system, and used for performing secondary purification on the crude carbon dioxide gas separated from the carbon and nitrogen separation system; and a nitrogen concentration and purification system communicated with the carbon and nitrogen separation system and the carbon dioxide secondary purification system, and used for purifying the nitrogen-containing vent gas separated from the carbon and nitrogen separation system and the vent gas generated by the carbon dioxide secondary purificatio

Abstract: In one aspect, a hybrid circuit protection device for current-limiting a fault current between a source and a load during a fault is provided. The hybrid circuit protection device includes an input configured to couple to the source, an output configured to couple to the load, a return configured to couple the source to the load, a main switch configured to selectively couple the input to the output, a switching network coupled in parallel with the main switch, and a controller. The controller is configured to determine that the main switch has opened in response to the fault current, where the fault current has an initial value, and activate the switching network to current-limit the fault current to less than the initial value during the fault.

Abstract: A system includes: a ring bus; a plurality of static uninterruptible power supplies (UPSs), each static UPS of the plurality of static UPSs including: at least one battery; an input that is electrically connected to a first external electrical power source; and an output that is electrically connected to a load, and, via a first corresponding choke, to the ring bus; at least one fuel-cell interface converter (FIC) that converts direct current (DC) electrical power to alternating current (AC) electrical power, each FIC of the at least one FIC being electrically connected to the ring bus via a second corresponding choke; and a fuel cell module corresponding to and electrically connected to each FIC, the fuel cell module including a fuel cell.

Abstract: According to one aspect of the present disclosure, an energy storage system includes one or more power sources, one or more energy storage components, and one or more solid state circuit breakers disposed between the one or more power sources and the one or more energy storage components such that electrical power is exchanged between the one or more power sources to the one or more energy storage components through the one or more solid state circuit breakers. The energy storage system also includes a controller configured to operate the one or more solid state circuit breakers to control current exchanged with the one or more energy storage components and protect the one or more energy storage components from the one or more power sources during a fault condition.

Abstract: Systems, methods, techniques and apparatuses of high current protection are disclosed. One exemplary embodiment is a power system comprising a solid-state circuit breaker including a solid-state switching device, an energy dissipation branch, an assistive branch, and a controller. The energy dissipation branch is coupled in parallel with the solid-state switching device and includes an energy dissipation device. The assistive branch is coupled in parallel with the solid-state switching device and includes a resistor, an inductor, and a galvanic isolation switching device coupled together in series. The controller is configured to determine the solid-state circuit breaker is conducting a high magnitude current, select a continuous current limiting mode or an intermittent current limiting mode, and operate the solid-state switching device based on the selected current limiting mode.

Abstract: Systems, methods, techniques and apparatuses of high current protection are disclosed. One exemplary embodiment is a power system comprising a solid-state circuit breaker including a solid-state switching device, an energy dissipation branch, an assistive branch, and a controller. The energy dissipation branch is coupled in parallel with the solid-state switching device and includes an energy dissipation device. The assistive branch is coupled in parallel with the solid-state switching device and includes a resistor, an inductor, and a galvanic isolation switching device coupled together in series. The controller is configured to determine the solid-state circuit breaker is conducting a high magnitude current, select a continuous current limiting mode or an intermittent current limiting mode, and operate the solid-state switching device based on the selected current limiting mode.

Abstract: A system for charging multiple electric vehicles is provided. The system includes a first electrical converter that supplies DC power to a ring bus. The ring bus is separated into a plurality of DC buses by electrical breakers. Second converters are connected to the ring bus and convert the DC power supply to a DC voltage suitable for charging electric vehicles connected thereto.

Abstract: Systems, methods, techniques and apparatuses of fault protection. One exemplary embodiment is a protection system including a solid-state switching device, a galvanic isolation switching device, and a controller. The solid-state switching device is coupled between a switch arrangement of a power converter and a direct current (DC) link capacitor of the power converter. The galvanic isolation switching device is coupled between the DC link capacitor and a DC network. The controller is structured to determine a fault is occurring within the DC network, open the solid-state switching device in response to determining the fault is occurring, receive a measurement corresponding to an electrical characteristic of a fault current flowing through the galvanic isolation switching device while the solid-state switching device is open, and determine a location of the fault based on the received measurement.

Abstract: A circuit protection system includes a plurality of circuit protection devices and a central controller. Each circuit protection device includes a protection switch for connecting or disconnecting a corresponding protected circuit, and a sensing module for sensing electrical parameter data. The central controller is in communication with each of the circuit protection devices, and is constructed to receive the electrical parameter data; determine whether a fault condition has occurred based on the electrical parameter data; and send a signal to open the protection switch for each protected circuit experiencing a fault condition.