474results about How to "Improve dynamic stability" patented technology

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one nitrate additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an organic alkyl nitrate compound.

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one nitrite additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an alkyl nitrite compound.

The present invention comprises a multilayered heel construction for footwear. A fluid-filled bladder is incorporated into the heel of footwear. The bladder defines an internal cavity which is adapted to enclose a fluid at atmospheric pressure. The internal cavity defines a peripheral channel adjacent the periphery of the bladder and a plurality of intersecting channels orientated transversely to the longitudinal axis of the footwear. The intersecting channels are in communication with the peripheral channel of the interior cavity. The bladder is positioned at the heel of the footwear and is positioned intermediate an upper footbed support. The lower surface of the multilayered heel assembly defines a concave, cantilever surface. The combination of the bladder, the upper footbed support and the lower cantilever surface improve shock absorption and the stability of the footwear.

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one dicarbonate additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an alkyl dicarbonate compound.

The invention discloses a VSG based photovoltaic microgrid dynamic frequency stability control method. The method includes the following steps: constructing a VSG based photovoltaic microgrid system dynamic model; performing adaptive control on the virtual inertia torque and virtual damping factors of the system model; configurating system key parameters, and selecting the optimal value of the parameters; and determining a calculation example, and adopting a simulation tool to perform simulation analysis on the calculation example. The method can establish the dynamic relation between the virtual inertia and virtual damping of a system and the frequency change of the system through the analysis on a frequency oscillation process, so that the two can be adaptively changed according to the frequency change, and therefore, frequency oscillation can be effectively inhibited, the system can better cope with transient disturbances, and the frequency stability of the system can be provided.

The invention relates to a high-rigidity nine-lever and two-freedom degree controllable mechanical loading mechanism, which comprises a machine frame, a movable arm control branched chain and a bucket control branched chain, wherein the movable arm control branched chain is controlled by a first driving lever and is used for elevating a movable arm; the bucket control branched chain is controlled by a second driving lever and is used for turning a bucket. The mechanical loading mechanism can complete loading and unloading operation by means of the interaction of the movable arm elevating branched chain and the bucket control branched chain. According to the mechanical loading mechanism, all the levers are connected through revolute pairs, and thereby the defects of high cost, low reliability, high maintenance cost and the like of the conventional full hydraulic loading mechanism with sliding pairs are overcome. Moreover, compared with other controllable loading mechanisms, the mechanical loading mechanism has the advantages of compact structure, high rigidity, and novel structure with superior kinematic and dynamic performance, and thereby the loading mechanism is higher in reliability and dynamic stability.

The invention provides a reconfigurable device for a walking robot with four/two parallel legs, belonging to the technical field of robots. The leg mechanism of the robot is structurally designed in a modularization way, and the legs are of a same structure. When four-leg walking is carried out, the leg mechanism is a 3-UPU, and when two-leg walking is carried out, the leg mechanism is a 3-SPU (Synergistic Processing Unit), wherein the conversion between the two leg mechanisms is realized through a rotation-pair retaining device, and the conversion between four legs and two legs is realized through a merging device. The rotation-pair retaining device comprises an electromagnet, an electromagnetic chuck base, friction plates, a friction plate carrier, a support column, a spring and a rotation-pair retaining plate, a rotation pair in a pair S is controlled to be locked and unlocked through the lamination and the separation of the friction plates, and the lamination and the separation of the friction plates are controlled by the sucker type electromagnet. The merging device comprises an electromagnetic chuck, a guiding device, a push-pull type electromagnet and a locking clamp, and the merging device is locked by controlling the positions of two legs to be merged, merging the soles through the electromagnetic chuck and the guiding device, and driving the locking clamp to act by the push-pull type electromagnet.

The invention relates to a system control method for a dynamic reactive power compensation device and belongs to the technical field of grid safety and stable control of a power system. The method includes: according to voltage and current of the dynamic reactive power compensation device accessed to the power transmission grid, switching states of parallel compensation equipment in a substation and manual setup of operators, quickly calculating reactive power requirement values of each functional mode of the dynamic reactive power compensation device, and determining which output of the functional modes can be selected by the dynamic reactive power compensation device to serve as reactive power reference instruction values. The method has the advantages of distinct control structure, simplicity in implementation and the like and overcomes the defect of single control function of a traditional control method. In addition, the control method can be applied to stable control of the power system, and voltage stability and dynamic stability of the power transmission grid can be improved.

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one carbonate additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate and an equilibrated mixture of dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is either a linear or cyclic carbonate containing covalent O-X and O-Y bonds on opposite sides of a carbonyl group wherein at least one of the O-X and the O-Y bonds has a dissociation energy less than about 80 kcal/mole.

A method and apparatus for interfacing the motion of a user-manipulable object with an electrical or computer system includes a user object physically contacted by a user. A gimbal mechanism is coupled to the user object, such as a joystick or a medical tool, and provides at least two degrees of freedom to the user object. The gimbal mechanism preferably includes multiple members, at least two of which are formed as a unitary member which provides flex between the selected members. An actuator applies a force along a degree of freedom to the user object in response to electrical signals produced by the computer system. A sensor detects a position of the user object along the degree of freedom and outputs sensor signals to the computer system. Another embodiment includes a host computer system and a local microprocessor, separate from the host computer, for communicating with the host computer and controlling the forces output by the actuators according to a processor subroutine selected in accordance with a host command, sensor signals, and timing information. Another embodiment of the interface apparatus uses voice coil actuators that produce forces in either linear or rotary degrees of freedom using currents applied in a magnetic fields. A friction drive mechanism of the present invention can be coupled between an actuator and a gimbal mechanism. Force from the actuator is transmitted to the gimbal mechanism through frictional contact of members of the friction drive mechanism.

The invention discloses an automatic material weighing method for a mine excavator. Rotating angles of all components are obtained through measurement of an angle sensor, real-time positions of all the components are calculated, then the kinematics parameters such as the speed and the accelerated speed of all the components are calculated through differential, the pressure of a big cavity and the pressure of a small cavity of an oil cylinder are measured through a pressure sensor, the real-time thrust pressure of the oil cylinder is calculated to obtain force parameters, kinematics equilibrium equations of all the components of the working device are set up by using the Alembert principle, the kinematics parameters and the force parameters are substituted into the equations, an equation set is solved in a simultaneous mode to obtain the total mass of materials and a bucket, the mass of the bucket is subtracted from the total mass to obtain the mass of the materials, the mass center of the materials is corrected according to the calculation results, the material density and the stacking state, and the accurate mass of the materials is finally obtained through iterative calculation. According to the automatic material weighing method for the mine excavator, calculation is performed according to the Alembert principle, the influence on measurement by various factors such as surface slope and rotation is considered, and therefore the automatic material weighing method has the advantages of being high in calculation accuracy and dynamic stability.