289results about How to "Achieving two-way flow" patented technology

The invention discloses an energy storing device for supplying valley current at the peak of electricity supply. The energy storing device comprises an electric return circuit formed by connecting the electronic components, wherein, a two-way converter is connected with a storage battery pack, a controller and a detection circuit; the controller is connected with a human-machine interface; the two-way converter is a voltage-type three-phase half-bridge rectifier / converter comprising three single-phase half-bridge converter bridge arms; the controller has a double-CPU structure with DSP (digital signal processing) chips and single-chip; the human-machine interface is a liquid crystal display (LCD) module; the detection circuit adopts the commercial power input detection, the converter output detection and the storage battery detection; and a hall sensor is used for sampling voltages and currents. By charging the storage battery when the electricity price is lower at the valley of the power supply and partially or fully discharging the load from the storage battery through inversion, the invention can solve the problem of the imbalance between supply and demand of the electric energy and achieve the effect of 'peak load shifting' as the effective supplement to the national grid.

The invention provides a network voltage disturbance generating device, which comprises a three-phase bridge type PWM (Pulse Width Modulation) rectifier and a three-H-bridge three-phase four-wire-system PWM inverter, wherein the alternating current side of the rectifier is connected with an electric network through an L type filter; the direct current side of the rectifier is connected in series with the direct current side of the three-H-bridge three-phase four-wire-system PWM inverter; an LC filter is connected to the alternating current side of the three-H-bridge three-phase four-wire-system PWM inverter; the output end of the LC filter is connected with an isolation transformer; and the secondary side of the isolation transformer is connected with a load. The invention further provides a control method suitable for the device. Due to the adoption of the device provided by the invention, the simulation of a network voltage amplitude, frequency disturbance and an electric network harmonic phenomenon can be realized, bilateral flow of energy can be realized, and active energy transmitted by tested solar-powered grid-connected equipment is fed back to the electric network; and the control method is easy and convenient to implement, and a target reference value can be accurately tracked; and moreover, quick response and small steady-state errors are realized, so that electric network disturbance can be simulated accurately.

The invention provides a net load interaction multi-dimensional operation system based on smart power grids. The net load interaction multi-dimensional operation system based on the smart power grids comprises a scheduling master station, a user substation, a communication net mobile terminal and a public network on-line device. The scheduling master station is used for formulating a scheduling policy through energy efficiency analysis and simulation modeling, obtained scheduling policy information is sent to the user substation which is installed on a user side through a transport layer. The user substation carries out self energy management, receives and processes the scheduling policy and then sends the scheduling policy to the communication net mobile terminal. Due to the fact that the communication net mobile terminal controls the user substation, an energy optimizing strategy and inquiry and management of a load power utilization condition and an operation state are achieved. The public network on-line device is used for supplying data and policy information to the scheduling master station through the transport layer and supplying electricity consumption information and service to public network users. The system arranges various terminal devices arranged in a scheduling data network, an information inner network, a public network, a communication network and an electric grid in different networks, interconnection and collaborative operation are carried out on the system to achieve intelligent demand response and construction of a demand side optimizing operation system.

The invention discloses an emergency traction power supply system of an electric motor unit, which comprises a traction transformer used for reducing high voltage of a contact network, two rectifiers used for rectifying alternating current of secondary side windings of the traction transformer into voltage of middle direct current links, two inverters used for taking electricity from the middle direct current links and performing inversion into three-phase alternating current, a two-way auxiliary current transformer used for taking electricity from the middle direct current links and performing inversion into three-phase alternating current or taking electricity from a two-way charger and then performing boosting and rectification into the voltage of the middle direct current links, an auxiliary load used for obtaining the three-phase alternating current from the two-way auxiliary current transformer or the two-way charger by an auxiliary load power supply busbar, and the two-way charger used for obtaining the three-phase alternating current from a three-phase alternating current output side of the two-way auxiliary current transformer and performing voltage reduction and rectification on the three-phase alternating current into direct current to supply power to a lithium titanate battery and a direct current load which are connected with the two-way charger, or used for taking electricity from the lithium titanate battery and performing boosting and inversion into the three-phase alternating current to supply power to the auxiliary current transformer.

The invention discloses an AC-DC hybrid micro grid bidirectional power converter virtual synchronization motor control method, and relates to the AC-DC hybrid micro grid virtual synchronization motorcontrol field; the bidirectional power converter is a three-phase voltage source type PWM converter formed by IGBT switch tubes; the AC side is connected to a AC bus via a LC filter and a line impedance Z ac; the DC side is connected to a DC bus via a DC capacitor Cdc and an line impedance Zdc; the energy bidirectional transmission can be realized respectively via a frequency control unit, a virtual excitation control unit and a bidirectional power transmission control unit; the AC frequency and DC voltage can be directly controlled so as to keep AC-DC subnet load balancing; throughput characteristics of various types of power supplies and loads of the AC-DC subnet can be fully utilized so as to provide inertia for the AC frequency and DC voltage, thus enabling the bidirectional power converter to present sagging characteristics under a stable state, and building a bidirectional power converter closed loop system small signal model so as to provide a key parameter design method.

The invention relates to a LCL (Lower Control Unit) filtering controlled rectifying active damping control method of electric currents on a feedback variable current side, belonging to an active rectifying method of power electronics. The method comprises the following steps: a direct current voltage control unit is used for finishing the control on a direct current voltage and producing d-shaft active currents of an electric current control unit; a q-shaft current given is used for controlling reactive components of a rectifier; a soft phase locking unit is used for locking a power grid voltage phase position and realizing the synchronous rotational transformation of the power-grid voltage and sampling currents on the variable current side; the current given and a sampling actual value are fed into the electric current control unit; the output quantity of the electric current control unit is accumulated with the electric current on the variable current side which is fed back by usinga first-order high-pass filter to generate the given quantity of a voltage space vector unit; and finally, the voltage space vector unit generates six PWM (Pulse-Width Modulation) signals to finish the control on the rectifier. The method solves the stability problem of a LCL (Low Control Unit) filtering voltage type controlled rectifier and realizes the control of the rectifier on direct-currentvoltages and currents on line side under the condition that the electric current or voltage detection of a capacitor branch is not needed.

The invention discloses a physical modeling system with a wind power generation, photovoltaic power generation and energy storage integration system. The physical modeling system is based on power output characteristics of a wind power generation system, a photovoltaic power generation system and an energy storage system, and a converter system is utilized to simulate the wind power generation system, the photovoltaic power generation system and the energy storage system. The physical modeling system comprises an upper layer management module, a wind power generation simulation module, a photovoltaic power generation simulation module, an energy storage simulation module and a simulation power distribution network module. The wind power generation simulation module and the photovoltaic power generation simulation module can simulate power trends of a wind power field and a photovoltaic power station according to a set environment parameter. The energy storage simulation module employs a set of reversely connected current transformers to carry out simulation. Charge and discharge characteristics of a storage battery can be simulated, and an instruction of the upper layer management module can be received. According to a practical requirement, active and reactive power is sent or absorbed to stabilize voltage or frequency fluctuation of the power distribution network module. According to the invention, an inverter is utilized to establish a physical model, and a bottleneck problem that wind power, photovoltaic power and energy storage integration generation research can not be realized in a laboratory physical system is solved well.

The invention relates to the technical field of power electronic current transformers, and provides a resonance-type power electronic current transformer and a current transformer device. The current transformer comprises an input-stage rectifying circuit and a rear-stage DC / DC circuit. The input-stage rectifying circuit comprises three bridge arms. Each bridge arm is composed of an upper half bridge arm body and a lower half bridge arm body. The midpoints of the bridge arms are connected with three phases of a high-voltage alternating-current power grid respectively. Each half bridge arm body comprises n module units. Ports of the module units are connected in a head-to-tail mode to form a bridge arm structure. Due to the high-frequency isolation of the input side and the output side, a heavy lower-frequency transformer is removed, and meanwhile efficient energy transmission and intelligent control are achieved. Harmonic wave transmission between different power grids and mutual influences caused by failures of the different power grids can be intercepted, meanwhile, the range of the output voltage is wide, continuous adjustment of the current and the voltage can be achieved, system operation information of the current transformer is easy and convenient to collect, mutual communication can be achieved among a plurality of current transformer systems, and the intelligent power grid is obtained.

The invention provides a super-capacitor energy storage and transfer-based active equalization system and method for a lithium battery pack. The active equalization system comprises an equalization main controller, a switch array, a two-way DC / DC, a super-capacitor, a current detection and power calculation device, a 16-bit decoder and a drive circuit, wherein the equalization main controller obtains a single battery voltage inspection value as an equalization state basis and any to-be-equalized battery is gated by the switch array to be connected to an equalization bus; the preceding stage of the full-bridge two-way DC / DC with an adjustable ratio is connected with the equalization bus and the backward stage is connected with the super-capacitor; the power of the equalization loss is calculated through the current detection and power calculation device; the equalization main controller achieves charging for the super-capacitor by a high-power battery through the two-way DC / DC; and the super-capacitor stores the power and then discharges a low-power battery through the two-way DC / DC until the equalization state. The power is stored and transferred through the super-capacitor; active equalization for the lithium battery pack is achieved; and the super-capacitor energy storage and transfer-based active equalization system has an important significance for prolonging of the lifetime of the lithium battery pack.

The invention relates to an LED (Light Emitting Diode) illumination intelligent control system which comprises a synchronous rectification unit used for providing direct-current power for at least two intelligent power control units, wherein the output end of each intelligent power control unit is connected with a corresponding LED light group unit via an electric wire; and the synchronous rectification unit is connected with each intelligent power control unit by a high-voltage direct-current bus. In the intelligent control system, stable constant-voltage direct current is provided for an LED illumination system by the synchronous rectification unit, so that the whole illumination system can operate under high power factor with less harmonic wave. the corresponding LED light group units are dynamically and precisely dimmed by the intelligent power control units, and the LED operation situation is detected in real time and communication with an external control center is carried out. The intelligent control system has the characteristic of reasonable structure, and is convenient to control, the working environment temperature of an LED light group can be improved, and the reliability and the service life of an LED illumination light can be improved.

The invention relates to a bidirectional multi-level buck-boost converter and a control method thereof. The bidirectional multi-level buck-boost converter is characterized in that the converter comprises a bidirectional three-level unit A (1), a bidirectional three-level unit B (2), an inductor Lb (3) and a control system; the bidirectional three-level unit A (1) comprises a switching tube T1, a switching tube T2, a switching tube T3, a switching tube T4 and voltage division capacitors Cb1 and Cb2; and the bidirectional three-level unit B (2) comprises a switching tube T5, a switching tube T6, a switching tube T7, a switching tube T8 and voltage division capacitors Cb3 and Cb4. The bidirectional multi-level buck-boost converter of the invention adopts a 'phase-shifted plus bidirectional' two-mode control method, two-way energy flow of the converter can be realized, and boost conversion and buck conversion can be simultaneously realized in two directions. The bidirectional multi-level buck-boost converter of the invention is especially suitable for high-voltage and high-power bidirectional energy flow situations.

The invention discloses a wireless charging apparatus with a bidirectional energy flowing function. The wireless charging apparatus comprises an input side controllable rectifying link which consists of an inductor L and power switching tubes Q1-Q4, a Z source converter which consists of inductors L1 and L2 and capacitors C1 and C2, a single-phase H-bridge inverter which consists of power switching tubes Q5-Q8, a wireless electric energy transmission mechanism which consists of a transmitting-receiving coil and a compensation network, and a vehicle-mounted controllable rectifying link which consists of power switching tubes Q9-Q12, wherein Q9-Q12 are connected with the capacitors C and the battery in parallel; and the compensation network comprises a primary side LCC compensating network which consists of a primary side compensating inductor Lp and two primary side compensating capacitors Cp and a secondary side LCC compensating network which consists of a secondary side compensating inductor Ls and two secondary side compensating capacitors Cs. The wireless charging apparatus has the functions of power factor correction and bidirectional energy flowing at the same time, and has high transmission efficiency.

The invention discloses a bi-directional power converter control method based on a virtual synchronous motor, and relates to the field of bi-directional power control in alternating-current and direct-current mixed micro-grids. A bi-directional power converter is of a three-phase three-leg structure formed by a switch tube and provided with a direct-current-side capacitor and an alternating-current-side filter inductor, alternating-current-side output voltage of the bi-directional power converter is equivalent to exciting electromotive force of the synchronous motor, alternating-current-side grid voltage is equivalent to terminal voltage of the synchronous motor, filter inductance is equivalent to armature winding of the synchronous motor, the bi-directional power converter can serve as the virtual synchronous motor after equivalence is achieved, an inertia simulation unit of the bi-directional power converter is provided with the direct-current-side capacitor, bi-directional transmission of energy is achieved by the aid of a virtual frequency controller, a virtual excitation regulator and a virtual motor control unit, direct-current voltage variation and alternating-current frequency fluctuation are decreased, the bi-directional power converter has a certain inertia, dynamic response of a system is improved, and the stability of the system is improved.

The invention provides a high-frequency isolation single-phase photovoltaic grid-connected system and a control method thereof. The high-frequency isolation single-phase photovoltaic grid-connected system consists of a photovoltaic array, a buffering capacitor, a high-frequency converter, a high-frequency transformer, an AC / AC converter, a filter and an electric power grid. A high-frequency chain-linked technology is utilized, so the electrical isolation between a photovoltaic power generation system and the electric power grid can be realized, the isolation transformer and the weight and the size of the entire system are reduced, only two-level power conversion is required, the topology is simplified, and the reliability of the entire system and the electric power transformation efficiency are improved. In addition, aiming at the characteristics of the topology and the photovoltaic system, an optimized control algorithm is proposed, so the unfavorable influence of the system from the fluctuation of the voltage outputted by the photovoltaic array can be overcome, the high quality of the electric power outputted by the entire system can be ensured, the distortions is small, the dynamic reaction is fast, the energy can flow in two directions, and reactive compensation can be supplied according to the requirement of the electric power grid.

The invention discloses a bus-based battery pack equalizer circuit. The bus-based battery pack equalizer circuit comprises N batteries; each battery is connected with a corresponding equalizer circuit and the equalizer circuit is connected to a controller; each battery is connected with one equalizer circuit and each equalizer circuit is connected to one controller; the batteries correspond to the equalizer circuits one to one and the equalizer circuits correspond to the controllers one to one; the controllers are used for controlling the equalizer circuits according to the energy information of the battery pack, and thus realizing two-way flow of energy between the battery module and an energy transmission bus and realizing equalized energy storage of the batteries; the N controllers are connected in parallel to a data bus and the N batteries are connected in parallel to an energy transfer bus; N is greater than or equal to 2.

The invention discloses a single-stage bidirectional isolation AC-DC converter, and belongs to the field of an electronic power electronic converter. The structures of three converters are each composed of single-phase AC sources, DC sources, Boost inductors, phase shift inductors, bus capacitors, transformers, primary power switch tubes, secondary power switch tubes and the like. The Boost inductors are connected to leg midpoints such that the integration of a bidirectional Boost PFC converter with a bridge type bidirectional converter is realized, through single-stage power transformation, two functions of PFC and isolation DC-DC transformation can be realized, and bidirectional flowing of energy is realized. The single-stage bidirectional isolation AC-DC converter, has the advantages of small power loss, high transformation efficiency, small switching loss, capability of realizing the bidirectional flowing of the energy, and the like, thereby being especially suitable for V2G and power network-storage battery energy storage systems.

The invention discloses an energy-feedback tractive power supply system with high power factor and high cost performance, relating to an energy-feedback tractive power supply system. The system comprises a main substation, a medium-voltage ring network, a first to an Nth energy-feedback tractive substations, a direct-current contact network and a steel rail. In the energy-feedback tractive substations, a set of 12-pulse-wave rectifier unit and a set of PWM (Pulse Width Modulation) unit are connected in parallel; by sufficiently utilizing respective advantages of the rectifier unit and the PWM unit, bidirectional flow of energy is realized on the one hand, braking energy of a train is fed back to an alternating-current grid, and electric energy is saved; on the other hand, the energy-feedback tractive power supply system integrates the advantages of simpleness and reliability, low cost and strong overload capability of a diode rectifier unit; beside, certain sensitive and capacitive reactive power is injected into the medium-voltage ring network by utilizing the PWM rectifier unit, and the power factor at the alternating-current incoming line of the main substation can be greatly increased. The whole tractive power supply system has higher cost performance.

The invention provides a disturbance generation device which is used for detecting the network access of a wind generating set and detecting and evaluating the grid-connected operation of a large-scale wind power station. The disturbance generation device generates various voltages for wind generator test, and comprises a low-frequency voltage disturbance device and a high-frequency voltage disturbance device, wherein the low-frequency voltage disturbance device is composed of a starting resistor, a reduction transformer, a filter, a parallel voltage source current converter module and a boosting transformer, and is used for realizing the function of low-frequency voltage disturbance; and the high-frequency voltage disturbance device is composed of a starting resistor, a rectifier transformer, a pulse-width modulation (PWM) rectifier module, a cascading H-bridge module and a filter, and is used for realizing the function of outputting second to twenty-fifth harmonic voltage, thereby realizing two-way flow of energy and meeting requirements of the wind generator for switching between a power-driven state or a power generation state.

The invention relates to an AC inductance-free energy-saving high-voltage DC traction power supply conversion device and a control method, which includes a multi-winding transformer and several conversion units. The multi-winding transformer consists of a primary winding and multiple secondary windings. Composed of windings, the number of circuits of the conversion unit is set corresponding to the number of secondary windings of the multi-winding transformer; the primary winding of the multi-winding transformer is connected to the AC power grid, and each secondary of the multi-winding transformer The side winding is connected to the input end of one converter unit, and the output terminals of each converter unit are serially connected in series to realize high-voltage direct current output. The invention saves electric energy, can ensure the stability of the DC power supply voltage, prolongs the power supply distance, and reduces the catenary loss. The invention can be widely used in urban rail transit traction power supply systems.

The invention belongs to a multi-level power converter technique, particularly relating to a topological structure of a cascade multi-level converter. In the invention, the amount of using direct current power supply is reduced under the condition of outputting the level amount which is the same as that output by the traditional cascade type converter. The implementation method is as follows: a capacitance is used to replace the direct voltage source in the traditional topology, and the capacitance voltage is maintained through disconnected charging for the capacitance. The topological structure is mainly used for a high-voltage and high-power situation, and a multi secondary transformer in the original cascade circuit is omitted. Under the condition that small harmonic wave of the traditional multi-level converter is retained and each power transistor only bears the haploid power supply voltage, sine wave output which is triple as big as power supply voltage amplitude can be obtained, and high-capacity and energy bidirectional circulation are easy to realize.

The invention relates to a multi-level converter employing a multi-winding intermediate-high frequency transformer. The multi-level converter comprises a voltage current measuring unit, wherein the voltage current measuring unit is connected between two ends of a power grid in parallel; the voltage current measuring unit sends a measured voltage current signal of the power grid to a control unit; a current signal output by the power grid is filtered and current-limited by an inducer and then is input in a H-bridge rectifier; the H-bridge rectifier converts the input alternating current into the direct current with stable amplitude according to the control signal sent by the control unit; the output end of the H-bridge rectifier is connected with a plurality of inverters; the output ends of the inverters are connected the input end of the multi-winding intermediate-high frequency transformer; the output end of the multi-winding intermediate-high frequency transformer is connected with a load converter through a plurality of rectifiers; a voltage current measuring module, all inverters and all rectifiers perform information interaction with the control unit; and the load converter supplies power to the load under the control of the control unit. The cost of the multi-level converter in the invention is saved; the size and the weight of the multi-level converter are reduced; and the multi-level converter can be widely applied in an electrical system and electric traction.

The present invention relates to a domestic energy local area network energy router. The router comprises a controller, a solid state transformer and a plurality of interfaces. The interfaces are respectively connected with a major network and a distributed power supply, an energy storage device and a load in a domestic energy local area network, the controller regulates the voltage of the solid state transformer which is a dual-way structure and comprise an input-level high-voltage three-phase rectifier, an isolated DC / DC convertor and an output-level low-voltage three-phase inverter which are connected in order, the DC / DC convertor is a dual-way symmetrical structure and comprises a single-phase full-bridge inversion circuit, a high-frequency transformer and a one-way bridge total control rectifying circuit, the single-phase full-bridge inversion circuit converts the high-voltage direct current of the major network to high frequency square wave to realize secondary side voltage reduction through the high-frequency transformer and output to the low-voltage direct current bus through the single-phase full-bridge inversion circuit, and the low-voltage direct current bus is connected with the domestic energy local area network through the low-voltage three-phase inverter. Compared to the prior art, the domestic energy local area network energy router and the control strategy thereof optimize the energy configuration, enrich the electric energy flow and has good application prospect.

A power electronic transformer having a multi-winding isolation transformer comprises a power electronic transformer basic unit module (1) connected with an isolation transformer having multiple input windings and single output winding and a low voltage output stage (5). The basic unit module (1) can form the power electronic transformer with single-phase or three-phase four-line input and three-phase four-line output. The basic unit module (1) comprises a high voltage input stage (2) and an isolation link stage (3). The high voltage input stage (2) is in serial connection and cascade connection through n-stage H bridge type power conversion modules. The isolation link stage (3) comprises a medium frequency or high frequency isolation transformer (4) having n groups of input windings and one group of output winding, n groups of H bridge type DC-AC power converts and a group of H bridge type AC-DC power converter (8). The low voltage output stage (5) comprises a three-phase four-line DC-AC voltage source inverter (10) connected with a common direct current bus.

The invention relates to an energy router device applied to an intelligent distributed energy network. The energy router device comprises an A unit being a three-phase pulse width modulation (PWM) bidirectional rectification unit, a B unit being an isolation-type bidirectional soft switch Cuk conversion unit, a C unit being a dual-active DC / DC conversion unit, a D unit being a three-phase four-wire soft switch inversion unit, an E unit being a soft switch single-phase full-bridge bidirectional inversion unit and an F unit being a photovoltaic Boost conversion unit and also comprises a first DChigh-voltage bus and a second DC low-voltage bus, wherein the dual-active DC / DC conversion unit comprises a closely-coupling high-frequency transformer, soft switching of each unit can be achieved byan auxiliary circuit or a control strategy, the energy loss and the loss of a switch tube device are greatly reduced. The distributed energy network is divided into three layers of power grid tree-shaped architectures by the intelligent distributed network technology, and the router is applied to a power distribution network and a micro power grid to complete different functions.

The invention discloses an integrated device of high-frequency PWM rectification and inversion as well as a control method thereof, belonging to the technical field of power electronic technology. The integrated device comprises a main circuit unit, a drive and power amplifying unit, a PWM unit, a central control unit, an HMI unit, a voltage current mutual inductor, a power parameter measuring unit and a power unit, wherein the main circuit unit is connected with the voltage current mutual inductor and the drive and power amplifying unit; the drive and power amplifying unit is respectively connected with the power unit and the PWM; the PWM is respectively connected with the power unit and the central control unit; and the central control unit is respectively connected with the power parameter measuring unit and the HMI unit. In the starting process of a permanent magnet synchronous generator, steps direct current is converted into alternating current, and high-frequency alternating current generated by the permanent magnet synchronous generator in stable running is converted into direct current when the permanent magnet synchronous generator stably operates, thereby realizing energy double-flow.

The triphase AC step-up type power factor correcting circuit is used in converter power supply. Up to now, there is no 10 KW level great power triphase power factor correcting circuit. The present invention features the Y-type connection to the triphase power network, and the power factor correcting circuit consists of three inductors, six diodes to constitute bridge rectifier and two capacitors connected serially. The present invention has simplified control, and can raise the power factor of arc welding converter power supply with capacitor filter rectifier circuit as input stage from 0.6-0.7 to 0.98-1.

Provided is a technology for analyzing user electricity data based on noninvasive intelligent monitoring. The technology adopts a data collection module, a data preprocessing module, a data communication module, an event detecting module and a load mark identification module to achieve the monitoring and analysis of the user electricity data, the data collection module is used for collecting the user electricity data, and the data preprocessing module is used for preprocessing an input signal and transmitting the input signal to a cloud service platform by the data communication module througha 5G network; the cloud service platform analyzes and saves the received data through the event detecting module, the load mark identification module analyzes an electrical load mark of the power user saved in the event detecting module, a model is built, the source of each mark feature sample is identified through a method of machine learning, and the monitoring and analysis of the user electricity data are achieved ultimately. The technology for analyzing the user electricity data based on the noninvasive intelligent monitoring has the advantages that effective technical support for the control of mutual energy flow between power users and electrical network enterprises, and the technology has a good application prospect.

The present invention discloses a large-capacity cascades multiphase multi- electrical level power converter without transformer, which belongs to high pressure large-capacity multiphase multi- electrical level frequency conversion technology field, and characterized in that a single-phase main circuit is composed by identical prime power convert unit through cascades; three single-phase main circuits are connected to the three phase electric network through star or triangle shape; the prime power convert unit constitutes 'back to back' AC-DC-AC inverter circuit topology through DC bus capacitance with multiphase inverter by H-type rectifying bridge; different electrical level, types, number of phases and connecting relation of the prime power convert unit can extends various different polyphase converter practical topology circuit, which saves phase-shifting transformer that original absolutely necessarily but volume weight covers more than one third of that of system, which reduces greatly volume and cost of complete appliance. The present invention is capable of realize high performance operation of speed governing system in four quadrant scope, can feedback energy from the electric motor to the electric network when the electric motor brakes, enhances working condition operation efficiency of speed governing system; and communicate electric network side current harmonics small and power factor close to 1.

The invention discloses a series-parallel type double-active bridge circuit, belonging to the fields of power electronics and electrotechnology. The bridge circuit comprises a first double-active bridge circuit and a second double-active bridge circuit, wherein input sides of the first double-active bridge circuit and the second double-active bridge circuit are connected in series and are subsequently connected with a high-voltage input grid side; output sides of the first double-active bridge circuit and the second double-active bridge circuit are connected in parallel and are subsequently connected with a low-voltage output grid side. By means of a mode that the input sides are connected in series and the output sides are connected in parallel, the requirements on voltage resistance grade of a switch tube of a high-voltage side are alleviated, the heating of the switch tube is reduced, and therefore the conductive consumption of the overall circuit is reduced. Therefore, the bridge circuit is high in energy conversion efficiency in the situation of large voltage change, and the bridge circuit can be used as a direct current-direct current conversion circuit of a bidirectional charger for charging and discharging power of a low-voltage battery pack.

The invention provides a distributed power system based on DC / AC bidirectional current transformer control. Battery super-capacitors are combined for forming a hybrid energy storage unit. A system DC bus is connected through a bidirectional DC-DC current transformer. Grid connection is performed through a bidirectional DC-AC current transformer. A bidirectional DC / AC current transformer DC bus voltage control strategy is designed. A distributed power system structure graph and a bidirectional DC / AC current transformer control structure graph based on DC / AC bidirectional current transformer control are presented. Furthermore through feedforward compensation control, constant DC bus voltage of a DC / AC unit control system is ensured, thereby keeping system energy balance and effectively restraining DC bus voltage surge in the presence of large power disturbance.