328 results about "Three phase system" patented technology

The invention relates to a method for separating rare earth ions by extraction of a liquid-liquid-liquid three-phase system, and belongs to the technical field of rare earth extraction and separation. The method comprises the following steps of: adding a chemical complexing agent into an aqueous solution containing the rare earth ions, regulating the acidity of the solution, adding a water-soluble high polymer and an inorganic electrolyte salt, oscillating and mixing at room temperature, and obtaining a liquid phase system of upper and lower layers; adding a hydrophobic ionic liquid, fully mixing the solution at room temperature, and obtaining an insoluble three-liquid phase coexistence system of upper, middle and lower layers; and respectively taking the upper, middle and lower phases ofthe three-liquid phase system, and reclaiming the rare earth ions by using an electro-deposition method. According to the method, a volatile organic solvent is not used, so that the phase forming behavior and the phase separation process of the three-phase system are easily artificially controlled; and light, medium and heavy rare earth ions are selectively enriched or grouped and separated in three different liquid phases respectively. Compared with conventional oil-water two-phase separation, the method has the advantages that: the process flow is greatly simplified, the method is quick in phase separation and avoids emulsifying, and the hydrophilic and hydrophobic properties of the ionic liquid three-phase system are easily controlled.

The invention provides an online monitoring method for a DC-link capacitor of a three-phase system. The method comprises that voltage of the DC-link capacitor is collected, and a voltage drop curve of the DC-link capacitor is obtained; three-phase output current is collected, and capacitive current is reconstructed according to the three-phase output current; and the capacitance (C) and equivalent serial resistance (ESR) of the DC-link capacitor are obtained according to the voltage drop curve and the capacitive current of the DC-link capacitor. The voltage drop curve and the three-phase output current of the DC-link capacitor as well as control signals of a semiconductor switch are monitored in the process that power equipment as a three-phase frequency converter is switched off, so that the C and ESR of the DC-link capacitor are calculated accurately, and non-invasive online monitoring for the DC-link capacitor of the AC / DC / AC system is realized. The method can be applied to online monitoring for an aluminum electrolytic capacitor, other capacitors as a film capacitor as well as other three-phase systems including a wind power converter, a photovoltaic AC / DC / AC system and a three-phase aviation power system.

A ground-fault circuit-interrupter method and system for three-phase electrical power systems including a plurality of GFCI units and a processor forming a ground-fault circuit interrupting system for use in a three-phase power distribution network including a three-phase source of electrical power, a three- or four-wire main circuit, and a plurality of three- or four-wire feeder circuits connected across the main circuit. A GFCI unit is provided in the main circuit and in each of the feeder circuits. The processor is programmed to continuously monitor the main GFCI unit and each feeder GFCI unit to determine when and where a fault has occurred and, in response thereto, to interrupt the faulted circuit and to inhibit tripping of the non-faulted circuits. The novel GFCI system is applicable for solidly-grounded, resistance-grounded, or ungrounded as well as other three-phase systems.

The invention relates to a method for three-phase extraction one-step separation of platinum, palladium and rhodium from leaching solution of a precious metal catalyst, which belongs to the technical field of solvent extraction and separation of the platinum, the palladium and the rhodium. The separation of the platinum, the palladium and the rhodium can be completed by adding hydrochloride, sulfate, nitrate or phosphate of sodium, potassium, lithium or ammonium into two non-polar and polar organic phases which can not be mixed and water solution containing the platinum, the palladium and the rhodium, and carrying out phase mixing under room temperature for obtaining a three-phase system. The separation of the platinum, the palladium and the rhodium can also be completed by adding a macromoleclar polymer and the hydrochloride, the sulfate, the nitrate or the phosphate containing the sodium, the potassium, the lithium or the ammonium into the water solution containing the platinum, the palladium and the rhodium according to proportion, further adding a non-polar organic solvent and carrying out the phase mixing under the room temperature for obtaining three phases. The method can simultaneously separate three phases of the platinum, the palladium and the rhodium with high separation selectivity from the failure extraction solution of a vehicle catalyst during the extraction process, and effectively simplify the existing lengthy and tedious two-phase extraction and separation process.

The invention relates to a low cost cement self-leveling mortar, which does not contain redispersible emulsion, and is doped with zeolite powder, wollastonite powder and fly ash on the basis of a three-phase system containing silicate cement, quick hardening cement and quick hardening anhydrite so as to meet practical engineering needs. The zeolite powder, the wollastonite powder and the fly ash, under the excitation of a cement hydrate, not only have self-maintenance and crack resistance, but also play a role in replacing the cement partially so that the performance of the prepared cement self-leveling mortar is superior to that of the self-leveling mortar added with a large amount of polymer rubber powder, and the cost of the prepared cement self-leveling mortar is comparatively lower.

The invention provides a method for selecting initial values of three-phase Newton-Raphson method power flow calculation of a power distribution network. The method comprises the following steps: S1, establishing a power distribution network three-phase system model; S2, establishing a power distribution network three-phase simplification system, and numbering nodes and branches of the power distribution network three-phase simplification system; S3, storing a three-phase load parameter of each node according to the serial number sequence of the nodes, and storing a three-phase impedance parameter of each branch according to the serial number sequence of the branches; S4, performing per-unit on the three-phase load parameter of each node and the three-phase impedance parameter of each branch; S5, establishing a power distribution network single-phase simplification system; S6, selecting convergence precision, performing power flow calculation on the power distribution network single-phase simplification system by a forward-backward sweep method to obtain the voltage amplitude and the phase angle of each node of the power distribution network single-phase simplification system; S7, selecting the initial value of the three-phase Newton-Raphson method power flow calculation of a power distribution network three-phase system. The method can select the initial value of the three-phase Newton-Raphson method power flow calculation by the forward-backward sweep method with high calculation speed and good convergence.

The invention relates to a coal bed gas high pressure desorption meter, while the prior coal bed gas high pressure constant temperature adsorption instruments utilizes coal powder samples to test coal bed gas constant temperature adsorption parameters, and the coal bed gas desorption test generally utilizes normal-pressure desorption instruments, to test the parameters of drilling well coal core, such as coal bed gas content and adsorption time and the like. The coal bed gas high pressure desorption meter comprises an automatic temperature control water bath apparatus, a stainless steel mechanical device, and an image and pressure data acquisition system, wherein the stainless steel mechanical device comprises a gas collection cylinder, a sample cylinder, a gas regulation cylinder, a frame, a high pressure pipeline and a valve, the cylinder is fixed on the frame, the frame and the cylinder are arranged in the automatic temperature control water bath device, and the frame is connected with a lifting machine. The invention can effectively simulate reservoir bed conditions and discharge-mining working systems, realize the switch between gas-solid two-phase system and gas-liquid-solid three-phase system under high pressure condition, the desorption, gas collection and measurement processes under high pressure water injection conditions, effectively observe the desorption of coal bed gas, and test the parameters such as desorption pressure, desorption quantity and lost gas quantity and the like.

Disclosed is a fault distance measurement method for a coupled double loop line through mode transformation of a six-phase system, belonging to the technical field of relay protection for an electric power system. In the method, a mode transformation matrix suitable for the loop lines is deduced from the fact that a single module is capable of reflecting the new mode transformation matrix of a common three-phase system according to the relationship between the impedance matrix of the common three-phrase system and the impedance matrix of the system of the double loop lines within the same tower. The invention provides a time domain fault locating method for double loop line based on new mode transformation. The method fabricates the criterion for distance measurement by making use of the transfer characteristics of the arc voltage and current under certain module. The method is characterized in that the measurement is carried out in time domain, the needed time window is short and the method avoids wave filtration; with the method of least square, the distance measurement precision is improved and the distance measurement precision is free from the influences from transition resistance, fault type and impedance change of the opposite system. A large number of electromagnetic transient simulation results show that the method is highly precise.

A broad-spectrum harmonic filter is developed. This filter is to be connected in series ahead of the load which generates harmonics. This filter basically consists of 3 fixed elements, i.e. a series reactor and a shunt reactor in series with a capacitor. It can function to completely filter out 5th harmonic current in 3 phase systems (or 3rd harmonic current in single phase systems) and to reduce other harmonic components by high percentages say, typically close to 70%. Thus the portions of various harmonics flowing toward the electrical power source can be held within acceptable limits.

The invention relates to a bi-directional power flow controlled multi-level mutual balance solid state transformer and a realization method thereof. The solid state transformer is a three-phase solid state transformer which is designed by using a mutual balance structure, and uses an AC-DC-AC three step type transform structure. A high voltage level, an isolation level and a low voltage level are comprised. The high voltage level and the isolation level are transformers with the same three-phase structure and are composed of sub units. The low voltage level is a single whole module which realizes an automatic mutual balance structure. Three-phase sub units of the high voltage level are connected in a star mode. The low voltage level is an alternating current output end with a three-phase four-wire wiring mode. The solid state transformer can realize power bi-directional flow. The whole three-phase system uses an independent structure, which is convenient for three-phase independent control and modular production. Through the direct current bus parallel module of the low voltage level, a three-phase electric power automatic mutual balance function is realized, so that the practical problem of the solid state transformer is solved.

A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

The invention belongs to low voltage electrical equipment, and relates to an operation mechanism and an arc extinguish chamber structure of an automatic changeover switch, in particular to a permanent magnet mechanism automatic changeover switch. The permanent magnet mechanism automatic changeover switch comprises two groups of dynamic and static contacts and arc extinguish chambers, a set of permanent magnet mechanism, and corresponding driving connecting rods and conducting rods, and is characterized in that: the permanent magnet mechanism is provided with three stable working positions andcan realize changeover control over the three working states of the automatic changeover switch; when the two groups of contacts are closed respectively, a permanent magnet provides holding force; when the two groups of contacts are opened at the same time, two opening springs provide the holding force; and an electromagnetic coil is electrified to work only during state changeover, so that the electric energy consumption of an electromagnetic mechanism is greatly reduced. When a three-phase system is formed, every phase adopts independent mechanism control so as to realize phase-separated operation, and arc-free break can be realized by phase-selected control; and the operation mechanism has a few parts, a simple structure and high reliability.

The invention disclose a three-phase unbalance management method and commutation system based on active power unbalanced automatic phase change control strategy which comprises the following steps: first, the imbalance degree of the three-phase system is calculated based on the load capacity and the positive and negative load in the three-phase system; whether commutation is switched and phase identification of the loading switching is needed to match the required change commutation capacity; at last the accessed phase is selected and accessed to correspondent with the to be switched phase, and then a phase-change switch which is adaptable to the load capacity and the change phase capacity is accessed, and the load is switched, so that three-phase active power tends to balance. The three-phase unbalance management method and commutation system based on active power unbalanced automatic phase change control strategy governs the three-phase unbalance phenomenon, the three-phase unbalance degree is reduced obviously, and the quality of the providing electricity is improved.

The invention belongs to the fields of carbon materials and electroconductive polymer composite materials, and relates to a preparation method of a poly(3,4-ethylenedioxythiophene) (PEDOT)-coated carbon nanotube composite material. The preparation method comprises: adding an oxidant solution, a carbon nanotube dispersion and a 3,4-ethylenedioxythiophene (EDOT) monomer to a three-phase system of an organic solvent, a surfactant and water, and carrying out an in-situ chemical polymerization reaction. The preparation method provided by the invention is simple, feasible and controllable, and is beneficial to large-scale synthesis. The composite material obtained in the invention has high electrical conductivity and higher specific surface area, so that the composite material is expected to have good application prospects in the fields of energy storage devices (including super capacitors, lithium ion cells and the like), sensors and the like.

The invention relates to a method for removing metal ion purity of rare earth solution aqueous solution aqueous solution extraction, and belongs to the metallurgy filed of rare earth extraction. The method comprises the following steps: hydroxylamine hydrochloride or ascorbic acid taken as a deoxidizer and a hydrosoluble chemical complexing agent are added to an aqueous solution containing various kinds of rare earth ions and purity metal ions of aluminum, iron and / or silicon; the pH value of the aqueous solution is regulated; a hydrosoluble high polymer and an inorganic electrolyte salt are sequentially added into the aqueous solution, and are vibrated and mixed at the room temperature, so that a polymer dual-phase aqueous system is obtained; an organic solution not dissolving in water is added, and a liquid-liquid-liquid three-layer liquid phase coexistence system is obtained. Purity metal ions of aluminum, iron and silicon can gather in a three-phase system polymer while rare earth ion selectively gather in the organic upper phase and / or brine lower phase of a three-phase system. The method can extract and separate rare earth ions, and extract and remove purity metal ions of the aluminum, silicon, iron and the like, and is simple in process flow and high in separation efficiency.

The invention discloses a three-phase power flow correction method for a power distribution network containing distributed power sources. The method specifically comprises the following steps that a distributed power source three-phase model is constructed; a power distribution network three-phase system model containing the distributed power sources is established; nodes and branches in the power distribution network three-phase system model are numbered; three-phase load parameters of all the nodes in the power distribution network are stored according to the numbering sequence of the nodes, and three-phase impedance parameters of all the branches in the power distribution network are stored according to the numbering sequence of the branches; the three-phase load parameters of all the nodes and the three-phase impedance parameters of all the branches are subjected to per-unit treatment; problems existing in power flow calculation of the power distribution network containing the distributed power sources are analyzed, and the grid-connected voltage of the distributed power sources is corrected; convergence precision is selected, a power distribution network three-phase system containing the distributed power sources is subjected to three-phase forward-back substitution power flow calculation. According to the method, the characteristic that the output current and the grid-connected voltage of the distributed power source model are symmetric is considered, and a positive-sequence component of the network-side voltage is selected as the grid-connected voltage of the distributed power sources to participate in power flow calculation.

The embodiment of the invention discloses an inverter. The collector of a power switching tube T1 is connected to the positive output terminal of a DC power supply; the emitter of the T1 and the collector of a power switching tube T2 are connected to one input terminal of an H bridge circuit, the other input terminal of the H bridge circuit is connected with the negative output terminal of the DC power supply, and the two output terminals of the H bridge circuit are respectively connected to a power grid; each power switching tube is inversely connected in parallel with a diode; a DC / DC converter is connected with two ends of the DC power supply; a capacitor C2 is connected between the positive and the negative output terminals of the DC power supply; a capacitor C1 is connected between the positive output terminal of the DC / DC converter and the negative output terminal of the DC power supply; the T2 is connected with the emitter of a power switching tube T7; and the collector of the T7 is connected with the positive output terminal of the DC / DC converter. The embodiment of the invention also discloses a dual topology of the inverter and other two inverters developed from the dual topology, and provides an application circuit of the four inverters, which is in the three-phase system. The embodiment of the invention has the advantages that high efficiency of the inverters are ensured, current leakage is reduced, and the problem of midpoint balance control to multiple levels is avoided.

The invention discloses a modular multi-level converter inter-phase power unbalance control method. A modular multi-level converter (MMC) system comprises three ends, that is, submodules having photovoltaic cell panels respectively, a DC power grid and a three-phase AC power grid. The control method comprises the following steps: obtaining output power of each submodule; carrying out three-end power control according to a system power allocation instruction; and when output power instructions of the three-phase cell panels are not equal, carrying out power tracking by injecting bridge arm zero-sequence ring current into each phase of bridge arm according to unbalance conditions, so that a three-phase system is allowed to operate stably according to a preset power instruction and balance of output power of the three-phase AC power grid is ensured.

The invention relates to a method for preparing a prostaglandin E1 lipid microsphere injection of a charging non-homogeneous phase (comprising a water phase, an oil / water interfacial film phase and an oil phase) dispersion system, of which the surface of the lipid microsphere can be charged with positive electricity or negative electricity. The prostaglandin E1 is alprostadil, of which the chemical structure comprises a basic skeleton of 20-carbon fatty acid with a 5-carbon ring and two side chains, wherein one side chain is provided with a hydrophilic carboxylic acid group, so that the prostaglandin E1 has the characteristic of light surface activity action. By utilizing the characteristic, and according to the formula and the preparation process provided in the invention, the prostaglandin E1 has an unique drug-carrying mode in a solution of lipid microsphere with the non-homogeneous phase dispersion system, and the prepared lipid microsphere injection is fundamentally different from an alprostadil injection(Kaishi, and is prepared by adopting the technology of the Japanese business corporation LTT Bio-Pharma Co., Ltd. already sold in markets, and the difference lies in that the drug-carrying mode is completely different, the content of degradation products in the preparation such as impurities is more than 50 percent lower than that of in the Kaishi, so that the prostaglandin E1 lipid microsphere injection and the alprostadil injection are fundamentally different. The invention relates to a method for preparing the prostaglandin E1 lipid microsphere injection and the drug-carrying characteristics thereof in a three-phase system; in the formula, 0.0001 to 0.1 weight portion of prostaglandin E1 is used as a drug, the prostaglandin E1 is added with auxiliary materials for medical purpose to prepare the prostaglandin E1 lipid microsphere injection, and the auxiliary materials for medical purpose comprises the following materials in portion by weight: 5 to 20.

The invention relates to the technical field of extraction and separation, in particular to a method for extracting and separating ions in two valence states of the same element in three phases. The method comprises the following steps of: 1) adding water-soluble high polymer, inorganic strong polyelectrolyte salt and a coordinating agent in turn into aqueous solution containing the ions in two valence states of the same element, and fully mixing to obtain mixed solution; and 2) regulating the pH of the mixed solution in the step 1), adding an organic extracting agent immiscible with water, fully mixing, standing and centrifuging to obtain a liquid-liquid-liquid three-phase system with coexistent upper layer, middle layer and lower layer, wherein the upper layer is an organic phase, the middle layer is an aqueous phase of the high polymer and the lower layer is an aqueous phase of the inorganic strong polyelectrolyte salt, and the ions in the two valence states are respectively extracted into the upper, middle or lower layer to realize the extraction and separation of the ions in the two valence states of the same element. By the method, the same element in two valence states is finely separated, and the problem of low recovery rate in a liquid-liquid extraction process is solved.

A phase-locked loop and method for estimating a phase angle of a three-phase reference signal is disclosed, which includes an adaptive quadrature signal generator configured to calculate an estimated first state and an estimated second state of a model of an unbalanced three-phase system at a fundamental frequency of the reference signal on a basis of the reference signal and an estimated fundamental frequency; a reference frame transformation block configured to calculate a direct component and a quadrature component in a rotating reference frame synchronous with an estimated phase angle on a basis of the fundamental positive sequence component and the estimated phase angle, and configured to determine an estimate of an amplitude of the fundamental positive sequence component on the basis of the direct component; and an estimator configured to determine estimates of the estimated fundamental frequency and the estimated phase angle on the basis of the quadrature component.

The invention discloses a common-mode-injection-based nearest level modulation method for a modular multilevel converter (MMC). According to the method, a common-mode component is injected into a three-phase nearest level modulation wave and the phase voltage magnitude level is reduced based on topping introduced by the common-mode injection, so that the number of sub modules needed by the bridge arm can be effectively reduced under the circumstances that the voltages of the sub modules are not changed; and in order to guarantee the unchanged voltage level of the direct current side, at least one invested sub module exists in the bridge arm at each moment after common-mode injection introduction. Moreover, because the same three-phase common-mode components, the wire voltage level of the three-phase system after injection is not changed. Therefore, under the circumstances that the power transmission level is not changed, the number of sub modules needed by the MMC can be effectively reduced, thereby reducing the MMC conduction losses at the same current level and realizing reasonable optimization of the total losses of the MMC system.

The invention discloses an imbalance compensation and the ant colony optimization method for an SVC. The method is based on a variable structure to control the SVC, wherein, the variable structure control method comprises two aspects of the unbalanced load equalization compensation and the parameter control of a PI controller, wherein, the unbalanced load equalization compensation adopts the SVC compensation susceptance computational method which is based on the synchronous rotation reference coordinate transformation of a virtual symmetrical three-phase system; meanwhile, in the stabilization control of the system voltage, the ant colony algorithm optimization method is adopted to real time adjust and to optimize the parameter kp and ki of the PI controller. The invention ensures that the SVC can not only complete the unbalanced load equalization compensation but also control the stabilization, thereby raising the precision of the susceptance computation of the SVC, guaranteeing the balance compensation of the charge, improving the performance in the stabilization control of the SVC voltage and maintaining the voltage stabilization of a common connection joint. Therefore, the invention has high robustness and high response speed.

An approach to modeling the nonlinear steady-state behavior of an electrical power grid in terms of equivalent circuits with currents and voltages as state variables is provided. Current and voltage conservation equations are formulated with circuit-theoretic algorithms that offer demonstrably superior robustness relative to traditional approaches. Generalized bus and line models are accommodated by the equivalent circuit-based approach, allowing for simulation of physical models not compatible with traditional methods. Unbalanced three-phase systems are handled without loss of generality. The provided methods allow for robust, efficient power flow simulation for contingency analysis, power system planning, power system design, power system control, component configurations and operating conditions, real-time scheduling, and optimization, among other applications.

The invention discloses a preparation method and application of a drug-loaded magnetic composite nanometer material. The fat-soluble solution (or emulsion) of the surface lipophilic magnetic nanoparticles and the drug is added to the dichloromethane solution of polylactic acid / glycolic acid copolymer (PLGA), and the three are mixed with each other to form an oil phase system. The oil phase system is added dropwise to the aqueous solution in which the surfactant Pluronic F127 is dissolved to form an oil-in-water system, and then the drug-loaded magnetic composite nanomaterial is obtained under the action of ultrasound. The drug-loaded magnetic composite nanomaterial can concentrate the drug in the tumor area under the action of an in vitro magnetic field to achieve targeting; the coating of PLGA solves the problem of mutual self-aggregation of magnetic particles, and the slow release control of the drug solves the problem It has great toxicity and side effects in the body and can be quickly taken up by tumor cells, leading to apoptosis of tumor cells and reversing the multidrug resistance of tumor cells.

The invention discloses an automatic power grid resonance detection method based on active injection current. For the problems of harmonic pollution due to a nonlinear load in a power system and resonance easy occurring when a reactive compensating capacitor is connected in the power system, an active power quality regulating device connected in the power grid in parallel is used for compensating the harmonic, and meanwhile, the active power quality regulating device is used for injecting reactive and harmonic combined current of a specific waveform into the power grid to automatically detect the resonance angular frequency and the damping coefficient of the power grid; for a single-phase system, the rectangular wave current of 180 degrees is injected; for a three-phase system, the rectangular wave current of 120 degrees is injected. According to the automatic power grid resonance detection method based on the active injection current, the resonance detection combined model of the optimal weight algorithm is established according to the harmonic voltage and the harmonic current of the power grid and spectral characteristics of the harmonic power, and then the resonance angular frequency and the damping degree of the power grid can be judged quickly and accurately; as a result, application basis is provided for the damping control of the power grid resonance and the power quality of the power system is further improved.

The invention discloses an input and output common-ground boost-buck photovoltaic grid-connected inverter and a control method thereof. The photovoltaic grid-connected inverter disclosed by the invention comprises five switch tubes, three diodes, two inductors and a capacitor. The input and output common-ground boost-buck photovoltaic grid-connected inverter has the beneficial effects that voltage at two ends of a ground parasitic capacitor of a photovoltaic cell panel is zero and remains unchanged; leakage current is effectively eliminated; input and output of the inverter are common-grounded and are beneficial to building of a three-phase system and the applications of the inverter can be further expanded; boosting and bucking can be achieved by a single stage of the inverter, the grid-connected voltage requirement can be achieved by a DC side only by low voltage and the application range of the inverter is expanded; a transformer does not exist in a circuit, the required active and passive devices are few and a system is high in efficiency, small in volume and light in weight; and an electrolytic capacitor does not exist in the circuit, the reliability of the circuit is improved and the service life of the circuit is prolonged.

The invention relates to control strategies of a three-phase inverter, and discloses a dead-zone compensation method of the three-phase inverter. The dead-zone compensation method of the three-phase inverter can effectively improve waveform distortion caused by a dead zone and reduce THD. The dead-zone compensation method is an off-line dead-zone compensation method and mainly comprises two parts including (1) accurate judgment on the inductive current polarity and (2) dead-zone compensation strategies under a, b and c coordinates according to a three-phase system. The accurate judgment on the inductive current fundamental wave polarity can further be divided into sampled inductive current polarity detection, electric current measurement circuit delay calculation and fundamental wave delay estimation caused by the dead zone, the inductive current fundamental wave polarity can be accurately obtained through the three steps, then the compensation strategies under the a, b and c coordinate system are adopted, therefore, extra delay caused by using a low pass filter is avoided, and compensation is turned to be simple and practical.

The invention discloses a control system and a control method of three-phase independent control grid inversion, wherein the control method of the three-phase independent control grid inversion comprises the steps: 1, error information between an electric supply phase angle and a lock phase angle is obtained by a DQ lock phase based on a closed ring lock phase of the three-phase system of a synchronous rotation coordinate system; 2, the voltage ring adopts comparison between the input voltage and the reference voltage; the obtained error signal is used as a current loop reference after being controlled and outputted by PI to perform PI control; 3, the electric supply valid value and the angle of the single-phase DQ lock phase are combined to replace the electric supply to generate a new front feed signal; and 4, the output of the current loop control and the quantity of the front feed control are used as final output quantity to be used as a modulation signal of SPWM (sinusoidal pulse width modulation) modulation so as to drive the inverter, therefore, the whole three-phase grid inverse system can run.