180results about How to "Seamless switching" patented technology

The invention provides a microgrid and microsource control method based on a virtual synchronous electric generator. The method comprises the following steps of building a mechanical equation and an electromagnetic equation of the virtual synchronous electric generator, carrying out microsource active control through active adjustment of the virtual synchronous electric generator, carrying out microsource reactive control through reactive adjustment of the virtual synchronous electric generator and achieving seamless switching between different operating modes of a microgrid. The microgrid and microsource control method based on the virtual synchronous electric generator has the active and reactive adjustment capacity similar to that of the synchronous electric generator, can simulate the inertia and the damping characteristic of the synchronous electric generator, can overcome the impact on a power grid from inertialessness of a traditional grid-connected inverter, and can effectively improve the capacity of the power grid to accept the renewable energy sources.

The present invention relates to a hybrid energy storage system and an energy management method thereof in a micro-grid. The system comprises a lithium iron phosphate energy storage system equipped with a lithium iron phosphate storage battery, a bidirectional energy storage AC/DC, and a super capacitor energy storage system equipped with a super capacitor, and is characterized by comprising a bidirectional energy storage DC/DC of which one side is connected with the super capacitor, and the other side is connected with a DC bus distribution line, wherein the DC bus distribution line is connected with one side of the bidirectional energy storage AC/DC, and the other side of the bidirectional energy storage AC/DC is connected with an AC bus distribution line. An energy management system detects and judges the charge states of the energy storage units of the hybrid energy storage system separately and real-timely, adjusts and controls the energy flow directions and amplitudes of the energy storage units of the hybrid energy storage system separately and real-timely, gives full play to the function that the super capacitor compensates the fluctuation of a power grid rapidly, satisfies the seamless switching and island transient operation requirements, keeps the uninterrupted power supply, enables the power supply reliability to be improved substantially, and realizes the operation benefit and cost optimization of the micro-grid.

The invention discloses a data processing method of a database. The data processing method comprises the following steps that a main node servo receives a data processing request of a client, wherein the data processing request comprises a data storage request; the main node server receives data to be stored; the main node server extracts various field values of one field of the data to be stored, calculates corresponding hash values and determines a storage position corresponding to each hash value; the main node server transmits the data to be stored and the hash values to a data node server; the data node server stores line data corresponding to the hash values into a corresponding main hard disc; and the main node server carries out mirror image back-up on the data stored in the data node server, wherein the data processing request also comprises data retrieval requests. The data processing method of the database, disclosed by the invention, is high in data processing efficiency and larger in capacity, and avoids the happening of single-site faults in a cluster.

The invention relates to an auxiliary satellite navigation system and a global positioning system (GPS) receiver, in particular to a high-sensitivity navigation receiver mainly used indoors as well as an indoor positioning GPS receiver and an auxiliary satellite navigation positioning system adopting high-sensitivity satellite navigation positioning technology. The system at least comprises a terminal receiver, a reference receiver, a positioning server and a communication network; all devices are combined into an integral indoor positioning system; the entire system is divided into a high-sensitivity satellite navigation receiver and a network auxiliary system. Through adopting the positioning mode in which point positioning under weak signal condition is combined with continuous positioning under strong signal condition, the method mainly solves related technical problems such as the organic combination of integral hardware implementation. The invention has the advantages that: the system and the method improve the sensitivity index of a terminal user and reduce first positioning time; moreover, the designed navigation receiver can process indoor weak satellite signal, etc.

The invention discloses a full-electronic security computer interlocking system. The full-electronic security computer interlocking system comprises a special railway security computer, an interlocker, a control and display machine and an electronic executing unit subsystem, wherein the special railway security computer comprises two security computers as a master computer and a spare computer; each security computer comprises a CPU (central processing unit) board and multiple communication boards; data transmission and data synchronization between a first CPU module and a second CPU module of the CPU board are finished through a two-port RAM (random access memory) and interrupt operation; the CPU board and the communication boards in a same system exchange data through the two-port RAM and the interrupt operation; during system operation, the first CPU module and the second CPU module output control signals for driving a master relay; and a normally open contact of the master relay is used for controlling acting power of onboard safety relays of all the communication boards. By a working method of the full-electronic security computer interlocking system, the special railway security computer can achieve functional safety of a double 2-vote-2 platform, can achieve short-period task-level synchronization of a single computer and two computers, and can achieve seamless handover under fault conditions.

The invention discloses a seamless switching method for multiple access points of a WiFi network. The method comprises the following steps of: collecting network information of a mobile terminal relevant to an access point by the access point, and uploading the network information to a trajectory prediction and analysis server; repeating the step a for at least five times; predicting the predicted access point of the mobile terminal by the trajectory prediction and analysis server; forwarding a data package to the predicted access point by an access point information dispatch server; building connection between the mobile terminal and the new access point. According to the seamless switching method for multiple access points of the WiFi network, packet loss probability is reduced and meanwhile switching delay is avoided, and seamless rapid switching among multiple access points of the WiFi network is achieved.

The invention provides a video definition switching method and a video player. The method comprises the following steps: loading a first fragment file of a first definition video from a preset second level buffer area into a video stream buffer area to be played; receiving a definition switching instruction; obtaining a configuration file of a second definition video from a video server according to the instruction, wherein the configuration file comprises time information and address information of each fragment file in the second definition video; determining a second fragment file conforming to a smooth switching condition in the second definition video corresponding to the first fragment file; loading the fragment files behind the second fragment file in the second definition video into the second level buffer area in sequence; and loading the fragment files into the video stream buffer area to start to play the second definition video after the first fragment file is played. The video definition switching method provided by the invention is used for realizing the seamless switch of different video definitions.

The invention relates to the field of automatic driving, and discloses a test system and a test method used for an automatic-driving simulation system. The test system includes a first automatic-driving simulation system. The first automatic-driving simulation system includes a simulation environment generation module and a data conversion interface. The method includes: generating a vehicle simulation environment; reading sensor data in the simulation environment through the data conversion interface, and converting the same into sensor data which can be identified by the second automatic-driving simulation system; receiving the sensor data, which can be identified, by the second automatic-driving simulation system, generating a second control instruction according to the same and a set test target, and sending the same to the data conversion interface; receiving the second control instruction by the data conversion interface, and converting the same into a control instruction which can be identified by the simulation environment generation module; and applying the control instruction, which can be identified, to a virtual vehicle by the simulation environment generation module toenable the virtual vehicle to run in a virtual scene. Therefore, a test on the second automatic-driving simulation system is realized.

The invention relates to a pre-synchronization control method based on virtual impedance, and belongs to pre-synchronization control methods. The pre-synchronization control method comprises a virtual impedance unit Xv exists at the two ends of a grid-connected switch Sg; the voltage Upcc of a node PCC and the grid voltage Ug are detected; and virtual active power Pv and reactive power Qv of a virtual reactance unit are calculated, PI controllers enable the virtual active power Pv and reactive power Qv to approach 0, when both the virtual active power Pv and reactive power Qv are 0, the voltage amplitudes of the two ends of the grid-connected switch Sg are the same, the voltage phases of the two ends of the grid-connected switch Sg are the same and if the grid is connected at this time, the instant impact current of grid connection is low, and it is ensured that an inverter is connected to the grid smoothly and friendly. A traditional pre-synchronization control method includes two phase-locked loops and needs a relatively large amount of PI regulators, and a traditional control system is complex. According to the pre-synchronization control method of the invention, the phase-locked loops are omitted, control is simpler, and the method is not influenced by delay and control precision of the phase-locked loops; only two PI controllers are needed, the complexity of an algorithm is reduced; and the output voltage of the inverter and the grid voltage are the same in both the amplitude and the phase, the transient impact current is reduced, and seamless switching between off-grid and grid-connection is realized.

The invention discloses a method for generating and playing a network video, which comprises the following steps: when a streaming media server receives a video command, storing an original code stream file from a front end encoder by the streaming media server; decoding the original code stream file stored by the streaming media server by a transcription server to obtain an original image sequence, performing N times downsampling on the original image sequence to obtain a subsequence of a corresponding frame rate, and encoding the subsequence to obtain a corresponding code stream file; and when a client requests multiple-speed playing of the network video, sending a code stream file corresponding to the requested multiple-speed to the client at a normal speed by the streaming media server. The invention also discloses a system for generating and playing the network video. The method and the system can reduce the network burden and improve the user experience when the client requests to play the network video at a multiple-speed.

The invention discloses a working method of a secure computer specially used for railways. The computer comprises two secure computers which are respectively used as a principal machine and a standby machine; each secure computer comprises a CPU (Central Processing Unit) board and a plurality of communication boards, wherein data transmission and synchronization between a first CPU module and a second CPU module of the CPU board are completed through a double-port RAM (Random Access Memory) and interrupt operation; the data exchange between the CPU board and the communication board positioned in a same system is completed through the double-port RAM and the interrupt operation; the first CPU module and the second CPU module output control signals used for driving a general control relay during the operation of the system, and the normally open contact of the general control relay is used for controlling onboard secure relays and active power supplies of all the communication boards. The working method disclosed by the invention can realize the functional security of a square two-out-of-two architecture platform through the secure computer specially used for the railways, realize the synchronization of the short-period task levels of the system and double systems and achieve seamless switching under the condition of a fault.

The invention relates to an energy internet oriented AC/DC hybrid microgrid coordination optimization control method and system, and belongs to the technical field of the energy internet and microgrids. The system comprises a plurality of sub microgrids, each sub microgrid consists of two interface converters which are connected with an alternating current bus and a direct current bus, the first interface converter adopts a current control closed loop, the second interface converter adopts a voltage control closed loop based on self-adaptive virtual impedance, and the power deviation of the two interface converters is used as an adaptive setting reference of the virtual impedance of the second interface converter. The first interface converter adopts the strategy of combining the power outer loop control and current outer loop control strategy and the current inner loop control strategy, the second interface converter adopts the strategy of combining the droop control outer loop and the voltage control strategy based on the self-adaptive virtual impedance and the current inner loop control strategy, by coordinated control of the adaptive virtual impedance, the performance of the AC/DC hybrid microgrid is improved.

This invention discloses a service switch system and its method for the network of the next generation, in which, a switch control point processes switch request and switch condition management, controls the switch and condition judgement in concentration, a service control point applies in setting up new session links and removing the original session link in the switch to be matched by the terminal and the access network node. In the process of switch, the terminal triggers switch request and the service control point reports the switch control point, which judges the switch condition and sends the switch instruction and the service control point sets up new links and removes the original one by signaling interaction to finish seamless switch.

The invention relates to a dual-air-compressor system and a control method for a hybrid power vehicle, and belongs to the technical field of hybrid power vehicles. According to the dual-air-compressor system and the control method, when an engine works, an air compressor of the engine inflates to supply an air source to the overall vehicle; when the engine stops at an idle speed and when the pressure of an air cylinder is lower than the lower limit value of the air pressure required by the vehicle, an electric air compressor works to supply the air source to the overall vehicle; when the pressure of the air cylinder is higher than the upper limit value of the air pressure required by the vehicle, an electric air compressor controller stops outputting; during the process, if the engine starts to work, then the electric air compressor controller stops outputting. According to the dual-air-compressor system and the control method, seamless switching can be realized and the safety of the vehicle can be guaranteed when any air source of the electric air compressor or the air compressor of the engine fails.

The invention is suitable for the technical field of communication, and provides a video recording method and device. The video recording method includes the recording mode switching step and the coding step, wherein the recording mode switching step includes the step of starting a rapid switching recording mode, a video data input source of a video module serves as a screen display module in the rapid switching recording mode, and the coding step includes the steps of initializing a coder, creating a video thread, conducting data coding on preview data output by the screen display module, and generating a video file. In this way, according to the video recording method and device, a user can rapidly switch a plurality of cameras in the video recording process in the rapid switching recording mode.

The invention provides an AP (Access Point) switching method based on double wireless network cards. A mobile terminal actively scans the signal intensity of an AP and then compares the scanned signal intensity with the current AP signal intensity, begins switching when the signal intensity is higher than the current AP signal intensity, otherwise, continues scanning till successful switching. In order to reduce the switching delay, aiming at the characteristic that the mobile path in an industrial application scene is substantially fixed, the invention provides a pre-learning mechanism, namely learning information such as AP position, switching sequence and the like of the application scene before formal application, and storing the information to a terminal node, so as to realize directional scanning and switching in formal application. The method solves the problem of quick AP switching in the industrial mobile network scene; uninterrupted switching is realized by adopting double wireless network cards; and the pre-learning mechanism is adopted for the specific industrial application scene to further reduce the scan delay.

The invention provides a method of associating a live program with an on-demand program of a smart TV. The method specifically comprises the steps of, when the smart TV plays a live program, sending a recommendation list which is formed by all the searched play information at each period to a mobile terminal automatically by the smart TV; by the mobile terminal, forming an on-demand order list, sending the on-demand order list to the smart TV, and sending an on-demand request to the smart TV; when the smart TV receives the on-demand request, calling a corresponding video source and giving watching order information to the URL of each video source; producing an on-demand switching time shaft by using playing duration of the called video source according to a playing sequence, and inserting a cursor point between adjacent playing durations; when the on-demand starting time arrives, displaying the on-demand switching time shaft on the smart TV; and when the playing progress passes the cursor point, turning to the corresponding video source automatically to realize seamless watching of each video source. The watching experience of the user is improved.

The invention discloses a photovoltaic grid connected inverter control method based on active power backup. According to the method, a traditional photovoltaic inverter is improved, a power ring is added between a voltage ring and a current ring, and seamless switching between maximum power tracking and active power backup state can be achieved through direct-current voltage ring and direct powerring control. By combining a fitting peak value judging method and a maximum power tracking control method, the maximum power point is determined, maximum power tracking is rapidly and seamlessly switched into the active backup state, and a traditional photovoltaic inverter achieves the active power backup function.

The invention relates to an off-grid and grid-connection control method and system for a virtual synchronous generator. A voltage error is calculated through a difference value between the grid voltage and the generator terminal voltage of the virtual synchronous generator, an electromagnetic equation and uncertain factor items; a sliding mode surface is designed according to the difference value between the grid voltage and the generator terminal voltage of the virtual synchronous generator and the voltage error; the difference value between the generator terminal voltage of the virtual synchronous generator and the grid voltage is controlled to be decreased according to the voltage error and the sliding mode surface through a fast terminal sliding mode control algorithm; when the voltage error is within a preset off-grid and grid-connection switching error range, off-grid and grid-connection switching is performed on the virtual synchronous generator. According to the off-grid and grid-connection control method and system for the virtual synchronous generator, due to the fact that when off-grid and grid-connection switching is performed on a generator terminal of the virtual synchronous generator, the generator terminal voltage of the virtual synchronous generator and the grid voltage are basically synchronous and a large impact current cannot be generated, the virtual synchronous generator can achieve seamless switching.

The invention aims at providing a method, a device and a system for achieving dynamic migration of virtual base stations in a BBU pool. A second virtual base station for accepting migration of a first virtual base station is determined by utilizing a migration management device according to a migration request of the first virtual base station; the first virtual base station sends a corresponding migration relevant parameter to the second virtual base station; the second virtual base station configures a corresponding communication tunnel according to the migration relevant parameter; the first virtual base station switches a corresponding data path and an interface to the second virtual base station according to the communication tunnel. Compared with the prior art, the method, the device and the system achieve non-destructive virtual base station migration, millisecond-magnitude-order service interruption time and packet loss freeing, ensure the service quality and enable users not to feel the migration process.

Disclosed is a micro-grid control method for communication-line-free interconnection based on frequency shift control. When a micro-grid runs in an off-grid mode, communication-line-free interconnection micro-grid control is realized with the aid of a power frequency signal of a voltage source, by use of a frequency shift control technology and by taking a frequency signal as a means of communication. No MGCC is needed, and an energy storage device is connected in parallel with DGs autonomously. Specifically, when a micro-grid runs in an off-grid mode, a virtual synchronous generator technology is used in main energy storage. Even if the power fluctuates largely, the system frequency is not beyond an allowed range as long as the maximum charge and discharge power of energy storage is not exceeded. The operation area is divided into three areas according to the SOC (State of Charge): a high-SOC charging sag operation area (50.3-51Hz), a low-SOC discharging sag operation area (47.7-49Hz), and a normal-SOC sag operation area or a high-SOC discharging/low-SOC charging sag operation area (49-50.3Hz).