3606 results about "Power compensation" patented technology

A system and method of reactive power regulation in a wind farm having a plurality of wind turbines that provides optimum control of the reactive power compensation in the wind farm and is able to keep a reactive power reserve in order to support eventual grid contingencies.

An integral method for realizing parallel generation and network reactive power compensation at the same time is based on the transient reactive power theory applying park transfer to transform a three phase inverter output current to a rotation dq coordinate to realize separation of active current and reactive current to convert the DC current of the photovoltaic to AC current by controlling the currents and directions carry out reactive power compensation to the local network. When a photovoltaic battery has enough energy to output, it realizes parallel generation and reactive compensation at the same time, when it stops the output, the inverter compensates the network independently.

An over-power compensation circuit for use in a switched mode power supply having a current sense circuit for sensing a current flowing through a power transistor of the switched mode power supply. The over-power compensation circuit includes a peak detector, a sample-and-hold circuit, a current offset generator, and an offset resistor. The peak detector has an input for receiving an input voltage derived from the input line, and an output. The sample-and-hold circuit has an input connected to the output of the peak detector, and an output. The current offset generator has an input connected to the output of the sample-and-hold circuit, and an output for providing an offset current. The offset resistor has a first terminal connected to the output of the current offset generator, and a second terminal adapted to be connected to a current conducting electrode of the power transistor.

The invention features a system for connection to a utility power network. The system includes a reactive power compensation device coupled to the network and configured to transfer reactive power between the utility power network and the reactive power compensation device; a capacitor system configured to transfer capacitive reactive power between the utility power network and the capacitor system; an electro-mechanical switch for connecting and disconnecting the capacitor system to the utility power network; an interface associated with the electro-mechanical switch; a controller configured to provide control signals for controlling the electro-mechanical switch; and a communication channel for coupling the controller to the interface associated with the electro-mechanical switch. The electro-mechanical switch, interface, controller, and communication channel together are configured to connect or disconnect the capacitor system from the utility power network within about three line cycles or less of the nominal voltage frequency when a fault condition is detected on the utility power network.

A reactive power compensation system includes a distributed energy resource situated at a local location configured to also receive power from a remote location by a distribution feeder line. The distributed energy resource includes an inverter including power semiconductor switching devices and an inverter controller configured for controlling the power semiconductor switching devices so as to provide reactive power support to the distribution feeder line.

The invention discloses an energy feeding type dragging power supply device and a control method thereof. The energy feeding type dragging power supply device comprises a multiple transformer and at least two four-quadrant converter modules. The energy feeding type dragging power supply device and a diode rectification dragging unit are arranged in parallel form. A primary side of the multiple transformer of the energy feeding type dragging power supply device is connected to an alternated current medium-voltage power grid through a high-voltage switch cabinet; each set of windings at a low-voltage side of the multiple transformer is connected to an alternated current side of one four-quadrant converter module; and the direct current sides of the four-quadrant converter modules are in parallel connection after being connected to a direct current side isolation switch and are connected to a direct current bus through a direct current switch cabinet and a cathode cabinet. The energy feeding type dragging power supply device can work at three different modes of dragging, feedback or SVG (Scalable Vector Graphics) according to the requirements. The energy feeding type dragging power supply device is compatible with an existing dragging power supply system under the condition of meeting a power grid compatibility demand. The energy feeding type dragging power supply device has the advantages of moderate cost, capability of solving the technical problems of feeding back a regenerated braking energy and stabilizing a dragging network voltage, and real-time static reactive power compensation capacity.

A method of providing reactive power support is proposed. The method includes detecting at least one of a plurality of network parameters in a distributed solar power generation system. The generation system includes a plurality of photovoltaic modules coupled to a grid via inverters. The method further includes sensing a state of the photovoltaic modules coupled to the distributed solar power generation system and determining a reactive power measure based upon the sensed state and the detected network parameters. The reactive power measure is used to generate a reactive power command. The reactive power command is further used to compensate reactive power in the distributed solar power generation system.

A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

A power compensation apparatus for a renewable energy system includes a plurality of converter modules positioned between any two phases of a three-phase AC electrical grid, each converter module including a plurality of inverter circuits connected in series. Each inverter circuit includes an energy storage unit for providing a direct current (DC) voltage; a capacitor connected to the energy storage unit; and an H-bridge circuit converting the DC voltage into an alternating current (AC) voltage. The converter modules perform reactive power compensation and active power regulation on the electrical grid in a delta connection. A plurality of converter modules are respectively positioned between any two phases of the electrical grid in a delta connection, so as to keep the voltage of the electrical grid continuously stable when the voltage of the electrical grid fluctuates, and also compensate load current when system load is not balanced.

The invention relates to a single-phase universal electric energy quality controller for power supply for electrified railways, and belongs to the technical field of flexible AC power transmission and distribution; the invention comprises a single-phase multi-coil transformer composed of a primary coil and n secondary coils, so that the secondary coils of the transformer can be connected in parallel with n voltage sources of current transformers; n capacitors are connected with n voltage source current transformers, so as to form a single-phase chain-type H-bridge current transformer with n chains; the AC terminal of the H-bridge current transformer is directly connected with the traction grid through a reactor. The invention has the functions of active power control, reactive power compensation and harmonic compensation, so as to resolve three-phase voltage unbalance, voltage fluctuation, low power factor and harmonic pollution and so on that exist in ER traction transformer stations, effectively lower the capacity of traction transformers, increase ER transport capacity and transportation capability. Moreover, the invention is characterized in small occupied area, little loss and low cost, in order to gain perfect harmonic suppression characteristics and dynamic response features, and provide convenience in industrial production and improve device reliability.

A power compensation differential scanning calorimeter that uses one absolute temperature measurement, two differential temperature measurements, a differential power measurement, and a five-term heat flow equation to measure the sample heat flow. The calorimeter is calibrated by running two sequential calibration experiments. In a preferred embodiment, the first calibration experiment uses empty sample and reference pans, and the second calibration experiment uses sapphire specimens in the sample and reference holders. In an alternate embodiment, sapphire calibration specimens are used in both the first and second calibration experiments.

The invention discloses an electrified railway traction power supply and energy storage device and a method of the electrified railway traction power supply and energy storage device. The energy storage device is connected between a feeding arm alpha or feeding arm beta at the output end of a traction transformer and a steel rail, or two energy storage devices are connected between the feeding arm alpha and the steel rail and between the feeding arm beta and the steel rail respectively, wherein the energy storage device is arranged in a traction substation. The energy storage device comprises a control unit, an isolation transformer, a PWM current transformer, an energy transformation circuit and an energy storage element, wherein the PWM current transformer, the energy transformation circuit and the energy storage element are connected in sequence, and the control unit is used for carrying out calculation according to the voltage, current and direction of the feeding arm alpha and / or feeding arm beta to complete control over the PWM current transformer and the energy transformation circuit and achieve energy exchange between the energy storage device and the feeding section connected with the energy storage device. The electrified railway traction power supply and energy storage device can fully recycle locomotive braking feedback electric energy, improve the energy utilization ratio of a traction power supply system, reduce the installation billing capacity of the traction transformer, reduce cost and absorb and store energy even in electricity valleys, has the effect of peak load shifting and further has the functions of dynamic reactive-power compensation and low-order harmonic suppression.

An LVRT control method for a grid-connected converter of distributed energy resources comprises steps of: obtain a positive sequence electrical component and a negative sequence electrical component during an LVRT period; outputting a compensation signal according to a power threshold withstood by a grid-connected converter to undertake reactive power compensation; and constraining the output power lower than the power threshold. The present invention uses the positive and negative sequence electrical components to undertake reactive power compensation, whereby to improve balance and stability of voltage during the LVRT period, avoid reverse torque and mechanical resonance, and prolong the service life of the power generator. Moreover, the present invention constrains the sum of the compensation currents below the power threshold to prevent the circuit of the power generator from being overloaded and damaged, whereby is prolonged the service life of the power system.

The invention provides a dynamic reactive power reserve optimization method for improving transient voltage stability of an alternating-current and direct-current power grid. The method comprises the steps of determining a key fault set and a key node set which influence the transient voltage stability of a power system, and sequentially ranking nodes; adjusting reactive power output of dynamic reactive power compensation equipment and calculating the trajectory sensitivity of the dynamic reactive power compensation equipment; ranking m dynamic reactive power compensation equipment and calculating the weight coefficients of the nodes in the dynamic reactive power compensation equipment; calculating the capacities of the dynamic reactive power compensation equipment, establishing a dynamic reactive power reserve optimization model and solving the dynamic reactive power reserve optimization model. The dynamic reactive power reserve optimization method for improving the transient voltage stability of the alternating-current and direct-current power grid provides auxiliary decision-making support for improving the transient voltage stability of the multi-direct-current-drop-point power grid, and has great importance in improving the allowance of the transient voltage stability of the large-scale alternating-current and direct-current power grid, establishing a smooth power transmission passage between a transmitting end and a receiving end, improving the transmission capacity of the alternating-current and direct-current power transmission passage and improving the operation economy and the power quality of the power grid.

A hybrid conditioner for filtering harmonics in a power system that includes a non-linear load. The hybrid conditioner includes an active filter structured and controlled to filter one or more high-order harmonic currents of the fundamental frequency, and a passive filter structured to filter one or more low-order harmonic currents of the fundamental frequency. The active filter and the passive filter are electrically connected in parallel with one another. The hybrid conditioner may also be for providing reactive power compensation for the power system, wherein the active filter is further controlled to provide a compensatory reactive power for compensating for the reactive power that is consumed by the load. The hybrid conditioner may also provide oscillation dampening for the power system, wherein the active filter is further controlled to damp oscillating currents that exist between the passive filter and the AC source.

The invention discloses a power compensation method for unbalanced direct power control of a voltage controlled grid-connected inverter, which is suitable for direct power control (the conventional direct power control) without synchronous speed rotational coordinate transformation. The method comprises the following steps of extracting negative sequence voltage signals and positive sequence current signals by collecting voltage and current signals of a three-phase electric network; and computing compensation items of active and reactive power according to selected control targets. In the method of the invention, the compensation items of active and reactive power are injected in the power reference signals of the conventional direct power control according to required control targets so as to respectively eliminate negative sequence current, double frequency fluctuation of the active power and double frequency fluctuation of the reactive power in the electric network, caused by unbalanced voltage in the electric network, and fit different application situations. The invention has the advantages of enhancing the capabilities of control and uninterrupted operation of the voltage controlled grid-connected inverter when the electric network is in an unbalanced fault.

The invention discloses a self-adaptive wireless charging system, comprising an alternating-current power supply, a load, an AC (alternating current) / DC (direct current) conversion module, a driving module, a driving coil, an emitting coil, a receiving coil, a load coil, a rectifying module, a receiving end impedance matching module and a feedback control module, wherein the alternating-current power supply is connected with the driving coil by the AC / DC conversion module, the driving module, the emitting end impedance matching module and the driving coil that are sequentially connected with one another; the driving coil is coupled with the emitting coil; the emitting coil can transfer energy to the receiving coil by magnetic resonance coupling; the receiving coil is coupled with the loadcoil; the load coil is connected with the load by the rectifier module and the receiving end impedance matching module that are connected with each other sequentially; and the receiving end impedancematching module is connected with the driving module by the feedback control module. The self-adaptive wireless charging system can control the transmitting power of the wireless power supply, can improve the stability and running efficiency of the system, can improve the power factor of the system by a power compensation unit, and can reduce energy loss.

The invention discloses a reactive-power control method of a wind power field, which is suitable for performing reactive-power coordinated control on a wind power field variable-speed constant-frequency wind power generating set and a reactive-power compensation device. The control method comprises the steps that: reactive-power requirements of the wind power field are calculated, and a correspondent allocation method is adopted according to the valid reactive-power power capacities of the reactive-power compensation device and the wind power generating set. Due to the adoption of the controlmethod, the reactive-power power adjusting capacity of the variable-speed constant-frequency wind power generating set can be adequately played, the coordinated control of multiple reactive power sources can be realized, and the oscillation situation caused by the adjustment can be avoided. When an electric power system has malfunctions, the reactive power adjustment is locked, so the system over-voltage caused by the excessive reactive power of the system after the malfunction is removed can be prevented. When the reactive power capacity of the wind power field is insufficient to maintain the voltage of an interconnected point, a prompting signal is transmitted, the active power of the wind power field is limited, and the coordination of the active power and the reactive power can be realized.

The high temperature secondary battery based energy storage and power compensation system is so formed that electric power supply system, electric load, and electric energy storage system including a high temperature secondary battery and a power conversion system, are electrically connected with one another. When operating normally, electric power is supplied from the electric power supply system to the electric load, while the electric energy storage system operates to effect peak shaving running and load leveling running. A high speed switch is provided between the electric power supply system and the electric energy storage system, so that when a voltage sag or a service interruption occurs while the electric power is being supplied from the electric power supply system, the voltage sag is immediately detected and the circuit is immediately shut off, an electric power is immediately supplied from the electric energy storage system to the electric load so as to compensate for the voltage sag or the service interruption.

A vector-controlled, dual inverter system for a three-phase induction motor is disclosed. The inverter system comprises a first inverter system which is connected to one end of three phase windings of a stator and performs compensation of a back electromotive force; and a second inverter system which is connected to the other end of the three windings of the stator and performs reactive power compensation.

A power converter circuit and associated triggering method for connecting a three-phase generator to an electrical network. The circuit includes a first direct connection of the generator to the network and a second connection of the generator to the network, through a four-quadrant converter which includes a first power converter, whose alternating voltage terminals are connected to the generator, and a second power converter, whose alternating voltage terminals are connected to the network. The triggering method for power compensation in the event of a short circuit is such that in a first period of time after the short, the second power converter outputs reactive power into the network; in a second period of time, the power converter feeds reactive power back into the network; and in a third period of time, the entire four-quadrant converter controls the gentle restarting, without loading the network with reactive power from the generator.

The invention discloses a power quality comprehensive compensation system of an electric railway and a control method thereof. The system comprises a railway static power controller RPC and two sets of thyristor switched capacitors TSC. The thyristor switched capacitors bear a large proportion of reactive power compensation, RPC performs active power compensation, harmonic suppression and a remained small proportion of reactive power compensation for two power supply arms, therefore, the capacity of RPC is effectively reduced, and negative sequence, harmonic and reactive comprehensive compensation are realized. The control method comprises a cooperative control policy of RPC and TSC, reference current detection based on reactive separation, a reactive power distribution method and an RPC control method. The power quality comprehensive compensation system of the electric railway greatly improves the power quality of the electric railway with low cost, and the corresponding control method effectively coordinates the operation of RPC and TSC and ensures that the system has good compensation performance and favorable application prospect.

A system and method may dynamically control the total RF power emissions of a mobile device. The method may include determining the local RF operating situation of the mobile device; setting a maximum power limit according to the local RF operating situation; and / or adjusting an active transmitted power of the mobile device within the maximum power limit. The local RF operating situation may be determined based upon (1) the measuring of a matching of the mobile device's radio antenna(s); (2) currently active application(s); (3) the number / type of active radios; (4) frequency or wavelength of transmissions; (5) network, relay, or node RF operating or exposure conditions; and / or (6) a power control process. The mobile device may be hand-held device, HomeNodeB, or other device capable of RF communications. The local RF operation situation and / or available headroom may be communicated to a network base station or node to facilitate enhanced mobile device performance.

The invention discloses a power distribution network reactive power optimization system and method based on multi-data analysis. The system comprises: a distribution network data acquisition device for acquiring 10kV line outlet node real-time data and transmitting the same to a host computer control system; a dynamic reactive power compensation device for uploading distribution network operating data and reactive power compensation device running status data to the host computer control system by using GPRS. The method, through the EMS and distribution network automation system, get access to the data of each node of a 10kV line, carries on the load flow calculation, obtains the distribution of the voltage, active power and reactive power of each node of the line, and makes the line run in an optimal state through reactive power strategy control, develop reactive power optimization strategy through a genetic algorithm to determine the compensation point, compensation capacity and the like, controls the reactive power compensation equipment in the distribution network to achieve full distribution network reactive power optimization operation control.

The related switch controller for output power compensation comprises: an oscillator to output an impulse signal, a waveform generation unit to receive the impulse signal and output a power limit signal, an impedance unit to decide the slope of the limit signal, a comparison unit to output a reset signal, and an output unit to receive the reset signal and impulse signal and output a drive signal to the power switch. This invention can obtain same output power for different input power voltages.

The invention provides a method for controlling the transmitting power of a sounding reference signal (SRS), user equipment (UE) and a base station. The method for controlling the transmitting power of the SRS comprises the following steps that the UE acquires multiple sets of SRS power control parameters and / or multiple SRS power compensation values provided by the base station for the UE; and the UE determines the transmitting power of the SRS by using one set of the multiple sets of SRS power control parameters and / or one of the multiple SRS power compensation values. According to the method for controlling the transmitting power of the SRS, the UE and the base station, multiple sets of SRS power control parameters and / or multiple SRS power compensation values are obtained from the base station, so that the transmitting power of SRSs transmitted specific to different aims can be controlled more flexibly, the accuracy of channel measurement is ensured, interference is reduced, and the power consumption of the UE is saved.

The invention discloses a dynamic reactive power compensation system and a control method thereof. The system comprises a static reactive power compensator (DSTATCOM) used for continuing a sub-system, and a thyristor switching capacitor (TSC) used for scattering the sub-system, and a controller, wherein, the static reactive power compensator consists of a three-phase voltage type inverter and an inductor, and is connected with a plurality of thyristor switching capacitors in parallel on an electric network; wherein, the controller comprises an artificial neural net controller which is in reactive power intelligent control grade and is accessed into the DSTATCOM and a capacitor circulated controller which is in decision processing grade and is accessed into the TSC for circulated switching control of the capacitors. The invention realizes high capacity reactive power quick and continuous compensation with low cost, high efficiency and energy conservation; the control method based on the artificial neural net provided by the invention can deal with various uncertain factors of a complicated power system during operation process so as to improve the anti-interference capability of the system, not only has better dynamic compensation characteristic, but also improves the robustness and control precision of the system.