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9467results about "Reactive power adjustment/elimination/compensation" patented technology

Modular charging/discharging system of power battery pack of multifunctional electromobile

The invention relates to a modular charging/discharging system of a power battery pack of a multifunctional electromobile, which aims to provide a system which can effectively meet the requirement for the bi-directional power transmission of a charging station and can exert the functions of peak clipping and valley filling as well as peak modulation and frequency modulation of a power grid. The technical scheme is as follows: the modular charging/discharging system of the power battery pack of the multifunctional electromobile comprises a charging-station monitoring system and an information management system, wherein the charging-station monitoring system is composed of a computer and a network communication system. The modular charging/discharging system is characterized by also comprising a three-phase step-down transformer, wherein the high voltage side of the three-phase step-down transformer is connected with a power grid, and the low voltage side of the three-phase step-down transformer is connected in parallel with a plurality of charging/discharging branches; each branch comprises a three-phase distribution transformer and a charging/discharging module, and the three-phase distribution transformer is connected in series with the charging/discharging module; and each charging/discharging module comprises a pulse-width modulation alternating current/direct current (PWM AC/DC) converter with the function of bi-directional power transmission, a plurality of electromagnetic isolation type DC/DC transform modules with the function of bi-directional power transmission and the information management system, and the electromagnetic isolation type DC/DC transform modules are connected in parallel.
Owner:梁一桥

Super capacitor energy storage type power quality compensator

The invention relates to a super capacitor energy storage type power quality compensator. A system structure comprises a compensation transformer, a series compensator, a parallel compensator, a super capacitor group, a current foldback circuit, a bidirectional DC/DC chopper circuit, a signal sampling circuit, a control circuit, a drive circuit, a human-computer interface and corresponding auxiliary circuits, which form a three-phase three-wire system topological structure. By utilizing the excellent characteristics of great power density, high charging and discharging speed and long cycle life of a super capacitor, the super capacitor energy storage type power quality compensator is matched with the DC/DC chopper circuit to form an energy storage control system which plays the roles of adjusting power and stabilizing the voltage of a direct current bus in work. The invention also has the functions of dynamic voltage recovery, active filter and reactive compensation and can ensure that a load can obtain rated sine voltage and the current of a grid is sine current with the same direction (unit power factor) with that of a voltage fundamental wave positive sequence active component, thereby comprehensively improving the quality of power. The invention has positive generalization and application value for both the public grid and users.
Owner:TIANJIN UNIV

Energy-saving type cascade multilevel photovoltaic grid-connected generating control system

The invention discloses an energy-saving type cascade multilevel photovoltaic grid-connected generating control system comprising an energy-saving cascade multilevel photovoltaic generating inverter, a controller and a power grid, wherein the multilevel inverter consists of 3n energy-saving type photovoltaic generating modules, wherein n modules are connected in series into one phase of a three-phase inverter; and the single-stage power of each module is converted to realize the buck-boost, the inverting and energy saving and adapt to the wide-range change of the battery voltage with high reliability. 3n photovoltaic cells and energy-saving cells are distributed on 3n modules; the generation of each module is independently controlled, thereby realizing the distributed maximum power track, collecting solar energy to the maximum extent, realizing high efficiency and avoiding the problems of power loss and hot spot caused by the local shade generated when the photovoltaic cells are connected in series; and the invention can flexibly control the stable power of a feeder grid of the multilevel inverter and achieve the functions of reactive power consumption, the power pitch peak control and the like, has the advantage of multilevel inversion and low output harmonic voltage and is suitable for high-voltage, high-power and transformer-free grid connection.
Owner:BEIJING JIAOTONG UNIV

An energy-feedback type traction power supply device and its control method

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.
Owner:ZHUZHOU CSR TIMES ELECTRIC CO LTD

Modularized multi-level converter with auxiliary diode

The invention relates to a modularized multi-level converter with an auxiliary diode. The modularized multi-level converter comprises a three-phase valve body, and three active energy feedback circuits respectively connected to the three-phase valve body, wherein each phase of valve body comprises 2M half-bridge inversion units and 2M-1 auxiliary diodes; direct current capacitors of the 1-(2M-1)th serially connected half-bridge inversion units are respectively connected with one auxiliary diode, and the final (2M)th half-bridge inversion unit is serially connected to form the valve body; the 1-Mth half-bridge inversion units form the upper-half part of the valve body to output a negative polarity voltage; and the (M+1)th to 2Mth half-bridge inversion units form the lower-half part of the valve body to output a positive polarity voltage. The auxiliary diodes and the active energy feedback circuits form a capacitor voltage sharing loop, the modularized multi-level converter realizes capacitance self voltage sharing effect, and realizes that the unit capacitance voltage is measured by using less direct current voltage sensors, thus the detection and the control of multi-level topology are greatly simplified. The modularized multi-level converter can be used in occasions such as reaction compensation and harmonic treatment of a medium-voltage or high-voltage power grid.
Owner:TSINGHUA UNIV

Active and reactive coordination control method for permanent-magnet direct-driven wind turbines in low-voltage ride-through process

Enclosed is an active and reactive coordination control method for permanent-magnet direct-driven wind turbines in the low-voltage ride-through process. Two different control strategies are employed for a grid side converter according to amplitude change of power grid voltage: when the power grid voltage is in a normal state, the grid side converter is in an active-priority maximum power tracing control mode so that the wind turbines capture wind energy to the maximum extent; when the power grid voltage is beyond the normal range, the grid side converter is in an active priority control mode so that the dynamic reactive current which is injected into an electricity system meets the requirements of grid combining. An engine side converter is in a direct-current voltage control mode based on rotor energy storage, power unbalance of the direct-current side of the engine side converter is relieved and the direct-current voltage is stabilized by utilizing the self rotating speed of the permanent-magnet direct-driven wind turbines and the change of the kinetic energy. The active and reactive coordination control for the wind turbines before or after the sudden change of the power grid voltage is realized according to the amplitude change of the power grid voltage, the fluctuation of the direct-current bus voltage is restrained by releasing or storing the rotor kinetic energy, so that the low-voltage ride-through capability of the permanent-magnet direct-driven wind turbines is improved, reactive power support is rapidly and accurately provided for the power grid, and certain support is given to restoration of the power grid voltage.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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