249 results about "Loop stability" patented technology

The invention discloses a transition metal sulfide / graphene composite material which is composed of a nano transition metal sulfide and graphene, wherein the transition metal sulfide is Ni2S3, NiS, FeS, FeS2, CoS, CoS2, CuS2, CuS, MnS or MnS2. Under the dispersion and loading actions of the graphene, the transition metal sulfide can be uniformly distributed and have small particle size, the stability and loop stability of the transition metal sulfide in the charging and discharging process can be effectively enhanced, and the composite material can be used as a lithium ion battery negative pole material. The invention also discloses a one-step low-temperature preparation method of the composite material, which has the advantages of simple technique, low cost, short cycle, low energy consumption and the like and is suitable for large-scale industrial production.

The invention relates to a lithium-titanate composite negative pole material and a preparation method thereof. The lithium-titanate composite negative pole material provided by the invention comprises lithium titanate, doping elements and a graphene / carbon nanotube composite material. The preparation method comprises the following steps: preparing a titanium source, a lithium source, soluble compounds of doping elements and the graphene / carbon nanotube composite material into a precursor by sol-gel in-situ synthesis, and calcining the precursor at 400-1100 DEG C to obtain the lithium-titanate composite negative pole material. The graphene / carbon nanotube composite material is utilized to effectively improve the electronic conductivity and rate capability of the lithium-titanate negative pole material; and the doping elements are introduced to effectively enhance the electrochemical properties and loop stability of the lithium-titanate negative pole material. The lithium-titanate negative pole material provided by the invention has wide application prospects in the field of lithium ion batteries.

A system and method for determining the desired decoupling components for a power distribution system having a voltage regulator module. The system may employ a mathematical model of a voltage regulator circuit, such as a switching voltage regulator. The mathematical model may be a SPICE model, or a circuit model in another format. The method may include simulating the operation of the power distribution system to obtain a estimate of the bulk capacitance required for effective decoupling. For digital systems, the method may include a cycle-by-cycle simulation of the power distribution system, wherein the simulation occurs over a number of clock cycles. The performance of the power distribution system may then be analyzed for each simulated clock cycle. The simulation may also include analyzing the transient responses and loop stability of the power distribution. Based on the results of these various simulations, the bulk capacitance value may be refined, thus allowing the system to begin the selection of specific decoupling components from the database in order to satisfy the bulk capacitance requirements.

The invention discloses a preparation method and application of a three-dimensional-structure graphene-base metal oxide composite material. According to the preparation method disclosed by the invention, the three-dimensional-structure graphene-base metal oxide composite material is prepared by a hydrothermal freeze-drying method by using single-layer carbon-atom-structure graphene as a carrier and some high molecular polymers as an auxiliary crosslinking agent. The three-dimensional aerogel obtained by the method has high metal oxide carrying capacity. The electrochemical test proves that the three-dimensional aerogel graphene-base metal oxide composite material obtained by the preparation method has excellent loop stability and rate capability. The experiment proves that the discharge capacity of the tin dioxide material can reach 1050 mAhg<-1> under the charging / discharging current of 100 mAg<-1>, and the discharge capacity of the titanium oxide material can reach 150 mAhg<-1> under the charging / discharging current of 50 mAg<-1>.

In a direct conversion radio frequency receiver, an automatic gain control is implemented that allows changing the operation mode of a filter unit in the baseband section of the receiver such that in a first operation mode filter capacities are selected to provide desired output signal characteristics, whereas in a second operation mode the filter settling time is significantly reduced in order to speed up gain adaptation and to improve gain loop stability. In one embodiment the cut-off frequency of a high pass filter and the Q-factor of a subsequent low pass filter are increased and decreased respectively upon changing the gain setting of a variable gain amplifier to accelerate settling of the filter.

The invention discloses a lithium vanadium phosphate anode material used in a lithium battery and a preparation method thereof, and solves the technical problem that can improve the electrical conductivity and high-rate discharge property of the anode material. The inventive anode material comprises a matrix coated outside with a conductive nano-composite material with a particle size of 5-50 Mu m and a specific surface area of 5-25m<2> / g. The inventive anode material is prepared by the following steps: wet-method superfine ball mill, liquid-phase mixture reaction, spray drying, pretreatment, calcinations treatment, coating with conductive composite material, and fusion. Compared with the prior art, the invention can synthesize lithium vanadium phosphate anode material by the secondary molding liquid phase method of nanoparticles, and the product purity is high, the particle agglomeration is efficiently prevented. The synthetic lithium vanadium phosphate anode material has a discharge voltage about 4V, three discharge voltage platform zones, higher charge / discharge capacity, excellent rate discharge capability and loop stability, and low cost; and is suitable for the industrial production.

A control circuit and method for a ripple regulator system generate a ripple signal in-phase and synchronous with an inductor current of the ripple regulator system, and extract a ripple information proportional to the amplitude of the ripple signal. The ripple signal is used for triggering control in PWM signal generation to make the ripple regulator system have small ripples and better loop stability simultaneously. The ripple information is used to improve the output offset of the ripple regulator system that is caused by the ripple signal.

A control circuit and method for a ripple regulator system generate a ripple signal in-phase and synchronous with an inductor current of the ripple regulator system, and extract a ripple information proportional to the amplitude of the ripple signal. The ripple signal is used for triggering control in PWM signal generation to make the ripple regulator system have small ripples and better loop stability simultaneously. The ripple information is used to improve the output offset of the ripple regulator system that is caused by the ripple signal.

The invention discloses a zinc-base complex oxide / graphene composite material which is in a laminated structure and is composed of a nano zinc-base complex oxide and graphene, wherein the general formula of the zinc-base complex oxide is ZnM2O4, and M is Mn, Co, Fe or Cr. Under the dispersion and loading actions of the graphene, the zinc-base complex oxide can be distributed uniformly and have small particle size to form a laminated structure, the stability and loop stability of the zinc-base complex oxide in the charging / discharging process can be effectively enhanced, and the composite material can be used as a lithium ion battery negative pole material. The invention also discloses a one-step low-temperature preparation method of the composite material, which has the advantages of simple technique, low cost, short cycle, low energy consumption and the like and is suitable for large-scale industrial production.

The invention relates to an automatic discovery method based on multi-service transmission ring network topology. Each node periodically sends topology auto-discovery frames along the ring; upon receiving topology auto-discovery frames, it updates the record of the source sending node in the network topology linked list of the node, and updates the change value of the number of ring network nodes and the ring stability flag and records them in topology frame, and forward it to the next node; when the topology auto-discovery frame returns to the source node, the local topology stability judgment is performed according to the change value of the ring network node number and the ring stability flag; after the topology is stable, each Nodes form a topological structure graph and save it on this node.

The invention provides a switching mode power source which comprises a rectification filter (1), a controller (2), a switching tube (3) and a transformer (4), wherein a primary coil (41) of the transformer (4) is connected to one end of the switching tube (3), the other end of the switching tube (3) is connected to the current detection end of the controller (2), the output end of the rectification filter (1) is connected to the power source input end of the controller (2), and the drive waveform output end of the controller (2) is connected to the control end of the switching tube (3). The controller (2) is used for outputting a drive waveform according to the input feedback voltage to control the on-off of the switching tube (3) so as to stabilize voltage or current which is output by asecondary coil (42). An auxiliary coil (43) of the transformer (4) is connected to the voltage input end of the controller (2) to input feedback voltage. Because a method of feeding back voltage fromthe auxiliary coil is adopted, the switching mode power source provided by the invention has the advantages of simple circuit and good loop stability.

A three-phase AC / DC active power converter provides an H-bridge that is controlled by a DSP (digital signal processing) controller that places the H-bridge in a voltage-boost mode of operation when voltage of a DC-link capacitor maintained by the H-bridge is near than the voltage input from a three-phase power source. The voltage difference between the boosted DC-link voltage and the three-phase power source voltage provides a voltage potential thereby giving the control loops a possible gain value. The gain value provides loop stability to thereby prevent an inrush of electrical current into the power converter upon startup. The converter also allows harmonic distortion to be modified through wave shaping of the normally pure sinus conduction signal.

It is an object of the present invention to provide a multilayer wire which can accomplish both ball bonding property and wire workability simultaneously, and which enhances a loop stability, a pull strength, and a wedge bonding property. A semiconductor bonding wire comprises a core member mainly composed of equal to or greater than one kind of following elements: Cu, Au, and Ag, and an outer layer formed on the core member and mainly composed of Pd. A total hydrogen concentration contained in a whole wire is within a range from 0.0001 to 0.008 mass %.

The invention discloses a preparation method of a tin-dioxide-coated carbon fiber material, and a product and application thereof. The preparation method comprises the following steps: depositing a tin dioxide film on the surface of natural cellulose by a sol-gel process by using tetraisopropyl stannate as a precursor and the natural cellulose as a template and carbon source, and calcining in an inert gas protective atmosphere to obtain the tin-dioxide-coated carbon fiber material. The raw material natural cellulose used as the template and carbon source has the advantages of wide sources and low price; the preparation method is simple and easy to implement, and has the advantages of low cost and no pollution; and when being used as a lithium ion battery negative pole material, the prepared tin-dioxide-coated carbon fiber material has the advantages of high specific capacity, high loop stability, long cycle life and the like.

The invention belongs to the field of integrated circuit design, in particular to a low dropout linear regulator with fast transient response. The regulator comprises a reference voltage source, an error amplifier, a series adjustment tube MNO, and a resistor feedback network composed of a first resistor R1 and a second resistor R2, wherein the regulator further comprises a buffer connected between an output end of the error amplifier and a gate end of the series adjustment tube MNO, a load transient response enhancement circuit connected between a gate end and a source end of the series adjustment tube MNO, an adaptive compensation control circuit connected between the error amplifier and the load transient response enhancement circuit, and a bias circuit that provides an operating current. Since the adaptive zero compensation improves the loop stability of the regulator, the NMOS series adjustment tube and the load transient response enhancement circuit enhance the load transient response of the regulator, the low dropout linear regulator with fast transient response achieves an improvement in load transient response performance of the low dropout linear regulator in the case ofhaving no off-chip capacitance and no significant increase in static power consumption.

In a frequency synthesis system with self-calibrated loop stability and bandwidth, a detector produces a detection signal based on a difference between an input signal and a feedback signal; a charge pump produces a control signal based on the detection signal; a filter produces a tuning signal and a source current based on the control signal; a bias circuit produces first and second bias signals; a controllable oscillator produces a differential output signal with a selected specific frequency; a differential-to-single converter produces an output signal with the selected specific frequency; a programmable frequency divider produces the feedback signal; a current mirror circuit receives the source current for producing a mirror current; a compensation circuit produces a compensation current based on the mirror current for compensating the variation of the damping factor and the bandwidth-to-reference frequency ratio.

The invention discloses a method for determining the equivalent aeroservoelasticity (ASE) robust stability of a statically unstable aircraft through a flight test, which is used for solving the technical problem of large modeling errors of the conventional flight test determination method. The technical scheme is that: a closed loop transfer function frequency characteristic matrix of a multi-loop system of the statically unstable aircraft can be obtained through a sweep frequency flight test; a relational expression between a closed loop transfer function and ASE stability is established according to a corresponding relation between the closed loop transfer function and an open loop transfer function; and the closed loop transfer function frequency characteristic matrix of the system is subjected to characteristic decomposition, and a multi-loop stability margin analysis scalar equation is obtained according to the critical stability condition of the system, so that the ASE stabilityof the whole loop is calculated, and problem difficulty is greatly simplified.

The present invention relates to a receiver apparatus, analog-to-digital converter apparatus, and method of converting an analog input signal into a digital output signal, wherein an additional direct feedforward path is introduced to compensate for peaking of feedforward structures while preserving frequency selectivity of the feedforward topology. In particular, the direct feedforward path (72) is provided with a scaling by a direct feedforward coefficient (ao) greater than zero and less than one. As a result, overshoot or peaking of classical feedforward topologies can be suppressed while providing interferer immunity, anti-aliazing effects and loop stability.

The invention discloses a tin-base complex oxide / graphene composite material which is composed of a nano tin-base complex oxide and a graphene, wherein the general formula of the tin-base complex oxide is M2SnO4, and M is Mg, Co, Ca or Zn. Under the dispersion and loading actions of the graphene, the tin-base complex oxide can be distributed uniformly and have small particle size, the stability and loop stability of the tin-base complex oxide in the charging / discharging process can be effectively enhanced, and the composite material can be used as a lithium ion battery negative pole material. The invention also discloses a one-step low-temperature preparation method of the composite material, which has the advantages of simple technique, low cost, short cycle, low energy consumption and the like and is suitable for large-scale industrial production.

The invention discloses an apparatus for eliminating a full-strapdown seeker guidance loop calibrated scale coefficient error, and a method thereof. The apparatus comprises an input module, a filtering module, an assessment module and a compensation module, a forced dither signal is superposed on overload instruction information through the input module, a projectile body forward channel and an attitude gyro compensation channel extract a line-of-sight rate signal and a projectile body attitude angle rate signal from signals filtered through the filtering module, the assessment module is used to establish a state equation, a measurement equation and a Kalman filtering equation, the estimation value of the calibrated scale coefficient error is assessed and calculated through the Kalman filtering equation, the compensation module multiplies the estimation value of the calibrated scale coefficient error with the projectile body attitude angle rate information and the multiplied compensation information is input to projectile body disturbance-containing inertial line-of-sight angular rate information in order to complete the compensation of the calibrated scale coefficient error, eliminate the influences of the calibrated scale coefficient error on a guidance loop, substantially improve the guidance precision and reduce the off-target amount.

The invention discloses an atomic magnetometer detection light frequency measuring and stabilizing device and method based on second harmonic. According t the method, based on the optical absorption effect and dispersion effect of an alkali metal atom gas chamber for detection laser and optical effects (such as an electro-optic effect, a magneto-optical effect, and a photoelastic effect) of a phase modulator, through monitoring a second harmonic signal outputted by an atomic magnetometer optical detection system, the detection light frequency is calculated in real time, with a servo controller and a closed-loop control algorithm, a control signal is fed to a detection light source control module to carry out corresponding adjustment, and the frequency online measurement of large detuning detection light and long time closed loop stability are realized. According to the device and the method, the advantages of system simplification, a small size, application range enlargement, real-time measurement and feedback are developed, the improvement of the sensitivity and stability of a miniaturized and integrated atomic magnetic field measurement device is facilitated, and the device and the method can be used for the industrial integration and practical application of a quantum sensing instrument such as an atomic magnetometer in the future.

In a direct conversion radio frequency receiver, an automatic gain control is implemented that allows changing the operation mode of a filter unit in the baseband section of the receiver such that in a first operation mode filter capacities are selected to provide desired output signal characteristics, whereas in a second operation mode the filter settling time is significantly reduced in order to speed up gain adaptation and to improve gain loop stability. In one embodiment the cut-off frequency of a high pass filter and the Q-factor of a subsequent low pass filter are increased and decreased respectively upon changing the gain setting of a variable gain amplifier to accelerate settling of the filter.

The invention relates to a preparation method of an expanded graphite / silicon@carbon negative electrode material for lithium ion batteries. The method comprises the following steps: introducing oxygen-containing functional groups to the lamellae of expanded graphite subjected to acid treatment to obtain oxidized expanded graphite, soaking the oxidized expanded graphite in an ethanol solution to obtain an oxidized expanded graphite ethanol solution mixture containing rich hydroxyls on the surface, stirring the mixture with a silane coupling agent to obtain an alkylated expanded graphite ethanol solution mixture, adding silicon nanoparticles to obtain an alkylated expanded graphite / silicon ethanol mixed solution, adding the mixed solution into an amorphous carbon precursor, reacting, collecting the precipitate, drying, carbonizing, and soaking in a hydrofluoric acid solution to obtain the expanded graphite / silicon@carbon negative electrode material for lithium ion batteries. The method has the advantages of favorable loop stability and favorable magnification property.

The invention discloses a method for determining the equivalent aeroservoelasticity (ASE) robust stability of a statically unstable aircraft through a flight test, which is used for solving the technical problem of large modeling errors of the conventional flight test determination method. The technical scheme is that: a closed loop transfer function frequency characteristic matrix of a multi-loop system of the statically unstable aircraft can be obtained through a sweep frequency flight test; a relational expression between a closed loop transfer function and ASE stability is established according to a corresponding relation between the closed loop transfer function and an open loop transfer function; and the closed loop transfer function frequency characteristic matrix of the system is subjected to characteristic decomposition, and a multi-loop stability margin analysis scalar equation is obtained according to the critical stability condition of the system, so that the ASE stability of the whole loop is calculated, and problem difficulty is greatly simplified.

A system and method for controlling a digital pulse-width modulated power converter achieves a fast large-signal transient response while maintaining a slow response near the steady-state operating point in order to assure stability and to reduce the system's susceptibility to noise. Digital output error samples are processed through a gain scheduling block that applies a non-linear gain function to produce a weak loop response when the system is near its steady-state equilibrium point and a strong loop response when large transients are encountered. The resulting system maintains a fast transient response to large error signals while reducing noise and loop jittering and assuring loop stability.

The invention belongs to the field of electronics and discloses a direct drive light-emitting diode (LED) driver. The driver adopts an isolation circuit to connect the output end of an LED lamp string and a constant current controller in coupling mode, output voltage of the driver changes automatically along with working voltage of the LED lamp string, and the driver can be applied to driving of the LED lamp string with various kinds of different working voltage. Accordingly, an error detection amplifying circuit in a feedback path is omitted, and stability and bandwidth of a return circuit are improved. Pulse width modulation (PWM) dimming can be conducted in a dimming range from 1% to 100% in uninterrupted mode. By means of the characteristics that when the working voltage of the LED lamp string is smaller than cut-in voltage of the LED lamp string, the current is zero, voltage difference of output voltage in an enabling period and a disabling period during PWM dimming is reduced, so that ripple voltage and electromagnetic disturbance are reduced.

The invention discloses a networked AC (alternating current) motor LS-SVM (least squares support vector machine) generalized inverse decoupling control method based on active-disturbance rejection. According to the method, an SVPWM (space vector pulse width modulation) controller, a three-phase voltage type PWM (pulse width modulation) inverter, a AC asynchronous motor, Clarke transformation, a rotor flux linkage observer and K / P transformation are connected to form a composite controlled object, and an LS-SVM generalized inverse system and the composite controlled object are connected in series to form a pseudo-linear composite system, and the AC asynchronous motor is decoupled into a rotating speed pseudo-linear sub-system and a rotor flux linkage pseudo-linear sub-system; active-disturbance rejection control is introduced into the pseudo-linear composite system, and networked closed-loop control is formed by communication network actuator nodes and sensor nodes. According to the technical scheme, the defects of low control accuracy, unknown AC motor model or parameters, difficulties in the inverse system construction under small sample condition, weak external disturbance robustness in a network environment, poor open-loop stability and the like in the prior art can be overcome, so that linear decoupling and high-performance control of the AC asynchronous motor can be realized in the network environment.

The invention provides a preparation method of a silicon oxide / carbon negative pole composite material for lithium ion batteries, belonging to the fields of new materials and electrochemistry. The silicon oxide / carbon composite material provided by the invention uses a porous carbon material with a xerogel or aerogel structure as a matrix, and silicon oxide particles are uniformly dispersed in the carbon matrix. Resorcinol and formaldehyde are used as matrix raw materials, organosilicon is used as a silicon source, and a one-step sol-gel method in combination with a heat treatment technique is utilized to prepare the nano silicon oxide / carbon composite negative pole material. The invention has the advantages of simple technical process, controllable reaction and mild conditions, and is convenient for large-scale preparation. The silicon oxide / carbon composite negative pole material prepared by the method has higher specific capacity and favorable loop stability, is an ideal lithium ion battery negative pole material, and can be widely used in the fields of various portable electronic devices, electric automobiles, aerospace and the like.