116results about How to "Improve transient characteristics" patented technology

The invention provides an AC servo system load torque and rotation inertia identification method and aims to achieve the fine dynamic and static characteristics of highly accurate control of a servo system according to the effect on the system performance by the permanent magnet synchronous AC servo system load rotation inertia and load torque. The method adopting the load inertia and motor rotor inertia as an entire inertia, allowing a servo system to perform regular forward and reverse speed increasing and decreasing movement, adopting a load disturbance torque state observer to observe the load disturbance torque changes of the motor, acquiring a model disturbance torque, adopting the integration identification algorithm, and identifying the system rotation inertia through mathematical derivation.

The invention is suitable for the technical field of optical communication and provides a hybrid optical fiber amplifier as well as a method and device for adjusting the gain and the gain slope of the amplifier. The hybrid optical fiber amplifier comprises an RFA (Raman fiber amplifier) and an EDFA (erbium doped fiber amplifier), wherein the EDFA excludes a variable attenuator; the RFA comprises a pump signal multiplexer, a pump laser group, an out-of-band narrow-band filter and a photoelectric detector; the EDFA comprises an input coupler, an erbium doped fiber, an output coupler, an input photoelectric detector and an output photoelectric detector, all of which are connected in sequence; and the hybrid optical fiber amplifier further comprises a control module for controlling the RFA and/or EDFA to adjust the gain and/or the gain slope according to an excepted amplification requirement. Due to the fact that the RFA and the EDFA are controlled and coordinated by the control module according to the technical scheme, an excepted amplification effect can be achieved; in addition, a series of problems caused by the variable attenuator can be avoided due to the fact that the EDFA excludes the variable attenuator.

A high-performance dynamic flip-flop circuit implementation. The dynamic flip-flop circuit comprises an "implicit" one-shot to generate a delayed clock output (319). The flip-flop comprises a delay block (317) coupled to a clock input (305). The flip-flop may be a D-type flip-flop. In a positive-edge-triggered embodiment of the flip-flop, a falling edge (440) of the delayed clock output (319) follows a rising edge (444) of a clock signal after a delay period (448). The flip-flop clocks in new data at a data input (305) in response to the clock input (310) during this delay period (448). Data is held in a storage block (360). The flip-flop has extremely good transient characteristics, especially set-up and clock-to-output times. The flip-flop consumes no static power.

The invention relates to a Rogowski coil-based integrator circuit for an electronic current transformer. The integrator circuit consists of a Rogowski coil, a low-frequency gain planarization analog integrator and a signal processing circuit, wherein the Rogowski coil is used for outputting a transient signal to the low-frequency gain planarization analog integrator and outputting a steady-state signal to the signal processing circuit; the low-frequency gain planarization analog integrator is used for processing the transient signal output by the Rogowski coil and is connected with the Rogowski coil and the signal processing circuit; and the signal processing circuit is used for processing an output signal of the low-frequency gain planarization analog integrator and performing digital integration on the steady-state signal output by the Rogowski coil, and then the processed signal is transmitted to a protecting channel and a metering channel through an output interface circuit. The integrator circuit has the advantages of measuring the steady-state signal with high precision, quickly responding to the transient signal, and providing measurement data of the protecting channel and the metering channel at the same time through one Rogowski coil, along with high temperature stability and vibration resistance.

The invention provides a back-to-back flexible direct current transmission system and a double-loop additional frequency control method. The back-to-back flexible direct current transmission system comprises a back-to-back converter body, a basic controller, an active additional controller and a reactive additional controller, wherein the basic controller is used for enabling DC-side voltage of the back-to-back converter body, the transmitted active power and reactive power absorbed or sent to a power grid to keep constant according to an instruction of a constant active power control loop, aninstruction of a constant reactive power control loop, an instruction of a constant DC voltage control loop and an instruction of a constant AC voltage control loop; the active additional controlleris used for performing proportional-integral control on a frequency deviation input signal to output an active power additional reference instruction value; and the reactive additional controller is used for performing differential control on the frequency deviation input signal to output a reactive power additional reference instruction value. According to the invention, frequency support for a disturbed alternating current system is realized through changing the active power instruction value and the reactive power instruction value.

The invention relates to a bearing fault diagnosis method under a strong noise variable speed condition based on an energy weight method. The method comprises the steps: extracting a vibration signalorder through employing a time-frequency ridge feature point linear interpolation and masking algorithm method according to a time-frequency representation graph based on Gabor transformation; performing instantaneous frequency estimation and secondary fitting on the vibration signal by using a local extremum search algorithm and the extracted order; carrying out equal-angle resampling on the vibration signal by utilizing a key phase time scale method according to the fitted instantaneous frequency; performing Hilbert-Huang transformation of CEEMDAN on the resampled isometric domain signal toobtain an order-frequency spectrum of the signal; extracting an impact energy occurrence position in the order-frequency spectrum, and then carrying out binaryzation on the order-frequency spectrum; acquiring an energy weight order sequence capable of reflecting impacts through multi-scale binary spectrum analysis, and carrying out power spectrum analysis on the energy weight order sequence to obtain fault-related impact components. The influence of strong noise and variable rotating speed on vibration signal analysis can be eliminated, and the accuracy of rolling bearing fault diagnosis is improved.

The invention discloses an adoptive sliding mode control method and an adoptive sliding mode control system of a wind power generation variable-pitch actuator. The adoptive sliding mode control system comprises a coder, a motion control card, a driving control plate, a frequency converter and a variable-pitch motor. The coder is used for detecting an actual mechanical position angle theta of the variable-pitch motor, the motion control card is used for receiving position instruction signals theta* sent out by a complete machine control system, the mechanical position angle theta provided by the coder is combined so as to achieve the adoptive sliding mode control method and work out that electromagnetic torque instruction signals Te* are sent to the driving control plate, and the driving control plate generates the driving signals according to the Te* and controls the variable-pitch motor through the frequency converter.

The invention discloses a switching converter and a control circuit and control method thereof. The control circuit comprises a ripple compensation module. According to a switching node voltage between a first switching tube and a second switching tube, a first driving signal of the first switching tube and a second driving signal of the second switching tube, the ripple compensation module generates a slope compensation signal and a direct current compensation signal, wherein the direct current compensation signal is a sampling signal of the slope compensation signal; a control circuit adoptsthe slope compensation signal to improve transient characteristics, and the direct current compensation signal is adopted to eliminate imbalance introduced by the ripple compensation module.

The invention discloses a magnetic isolation drive circuit comprising an isolation drive transformer, a first capacitor C1, a second capacitor C2, a discharge MOS pipe and a discharge MOS pipe drive circuit, wherein the isolation drive transformer is used for transmitting an isolation drive signal; the first capacitor C1 is connected with the input side of the isolation drive transformer in series; the second capacitor C2 is connected with the output side of the isolation drive transformer in series; the discharge MOS pipe is connected with the output end of the magnetic isolation drive circuit in parallel; the discharge MOS pipe drive circuit is connected to a grid electrode of the discharge MOS pipe; and a series loop is formed by an output side winding of the isolation drive transformer, the second capacitor C2 and the discharge MOS pipe. The magnetic isolation drive circuit has simple structure and low cost and can effectively increase the stability of a power supply which works in a stable state and a transient state.

The invention relates to a test system for transient step response of a flexible direct-current electronic voltage transformer, wherein an EVT digital value receiving module is used for receiving a sample signal sent by a merging unit of a tested direct-current electronic voltage transformer, and a signal conditioning loop is used for sending a digital signal of a standard signal; a clock module is respectively used for controlling the standard signal and the sample signal to have an uniform time sequence and time scale; the synchronized standard signal and sample signal are processed by a step high value calculation module and a step low value calculation module; the stable direct current components of the standard signal and sample signal are processed by a 10% time calculation module and a 90% time calculation module; the output values of the 10% time calculation module and 90% time calculation module are input into a step response delay calculation module, and the step response delay calculation module is used for calculating the difference value of the time moments corresponding to the standard signal and the sample signal respectively. The system meets the requirement of flexible direct current transmission on the reliability of the flexible direct-current electronic voltage transformer.

The invention provides an electric-assistance variable nozzle turbocharging system, and belongs to the technical field of turbochargers. The electric-assistance variable nozzle turbocharging system and the control method thereof aim at enabling a motor and a turbine variable nozzle ring to be coordinated through the influences of the motor and the turbine variable nozzle ring on performance of an engine. A diesel engine cylinder is directly connected between a gas inlet branch pipe and an exhaust branch pipe of the system. A gas inlet pipe is connected to the gas inlet branch pipe. An exhaust pipe is connected to the exhaust branch pipe. An intercooler is installed on the gas inlet pipe. An electric-assistance variable nozzle turbocharger is installed at an inlet of the gas inlet pipe and an outlet of the exhaust pipe. According to the electric-assistance variable nozzle turbocharging system and the control method, the high-speed motor is controlled on the basis of the air-fuel ratio of a diesel engine and the state of a storage battery, the gas inflow amount of the cylinder can be effectively and rapidly regulated so as to be matched with the changes of the oil spray amount, coordinated synchronization of oil and gas is achieved, it is ensured that the diesel engine keeps an appropriate air-fuel ratio value under various working conditions, and meanwhile it is ensured that the battery works in a high-efficiency area.

The invention discloses a neural network based inversion global sliding mode fuzzy control method for an active power filter. A neural network based inversion global sliding mode fuzzy control system is composed of an inversion PID global sliding mode controller, a neural network dynamic property estimator and a fuzzy uncertainty approximator. Global sliding mode control can overcome shortcomings of robustness insufficiency of an arrival mode in traditional sliding mode control and accelerates system response so as to enable the system to have robustness in the whole process of response. Due to approximation of switch function items by adopting fuzzy control, switch items of sliding mode control are converted to continuous fuzzy control output, so that chattering in sliding mode control is relieved and comparatively high self-adaptive tracking capability is achieved. Therefore, through combination of inversion PID global sliding mode control and neural network fuzzy control, advantages of inversion PID global sliding mode control and neural network fuzzy control can be fully played, transient performance and robustness of the sliding mode control system can be improved and chattering in variable structure control is reduced.

A magnetic isolation grating driver includes a driver generating pulse width variable signals, a pulse isolation transformer, an input capacitor serial to the input of the transformer, an output capacitor serial to output of the transformer, an output diode parallel to the output of the magnetic isolation grating driver, output small power MOS fieldistor serial to the capacitor of the output which source is connected with a terminal of the transformer output and the grating to the other, the transformer output , the output capacitor, the diode and the MOS fieldistor make up of a serial circuit.

The invention discloses a JFET (Junction Field Effect Transistor) and a manufacturing method thereof, and a micro inverter using the JFET. The JFET comprises a drain ohmic contact electrode, a substrate, a SiC drift layer, an N-type SiC channel layer, an N-type SiC ohmic contact layer and two gate Schottky contact electrodes. The manufacturing method comprises the following steps of providing the substrate; forming a SiC epitaxial layer; forming the N-type SiC channel layer and the SiC drift layer; forming the N-type SiC ohmic contact layer; forming drain and source ohmic contact electrodes; and forming the two gate Schottky contact electrodes. The micro inverter comprises capacitors C1, C2 and C3, an inductor L1, a JFET1, a JFET2 and a JFET3, and silicon carbide Schottky diodes D1, D2, D3 and D4. According to the JFET, the manufacturing method thereof, and the micro inverter, the realization is convenient, the cost is low, the working frequency and the working reliability of the micro inverter are improved, the loss and the price of electric energy are reduced, and the practicality is high.

The invention discloses a dynamic PID global sliding mode control method for an active power filter neural network. A dynamic PID global sliding mode control system for the active power filter neural network is composed of a dynamic PID global sliding mode controller and a neural network indeterminacy estimator; global siding mode control can speed up a system response, and thus the system has good robustness during a whole response process. An integral item is introduced into the design of a sliding mode surface to restrain steady-state errors and enhancing robustness, and a buffeting phenomenon can be reduced by dynamic sliding mode control, and therefore, combination of a PID global sliding mode and a dynamic sliding mode can bring advantages of the two ones into play at the same time, transient performance and robustness of the sliding mode control system are improved and buffeting existing in sliding mode variable structure control is reduced; for unknown nondeterminacy, the neural network is added to approximate undetermined items, a switching item of the sliding mode control is converted into a continuous neural network output, the buffeting phenomenon in sliding mode control is further weakened, malfunction of an IGBT is avoided, and the system performance is optimized.

The invention is applicable to circuit design, and provides a novel slew rate enhancement circuit comprising a plurality of MOS tubes and a plurality of capacitors; the plurality of capacitors are used for detecting the change of feedback voltage input from the outside, and sending a control signal to the plurality of MOS tubes when detecting that the feedback voltage changes; the plurality of MOStubes are used for controlling rising or reduction of voltage output from the output terminal of the novel slew rate enhancement circuit according to the control signal, so that limitation of the slew rate of a power regulation tube connected with the output terminal of the novel slew rate enhancement circuit is improved. The novel slew rate enhancement circuit provided by the embodiment of the invention can improve the limitation of the slew rate of the power regulating tube at the moment of load jumping change, so as to improve the integral instant response and reduce quiescent current. When load current generates transient change or generates switching rag and peak, change of output voltage can be rapidly detected by the feedback voltage, and charging and discharging can be performed on the grid capacitance and Maitreya equivalent capacitance of the power regulating tube, and finally the transient characteristic of the circuit is greatly improved.

The invention discloses a novel full-fiber current transformer of an isolation circuit breaker type, and the current transformer comprises a circuit breaker arc extinguish chamber (1), a full-fiber current transformer sensitive ring (2), a wiring terminal board (3), a fiber composite bushing (4), a full-fiber current transformer electrical unit (5), a polarization maintaining fiber (6), an insulating ring (7), a conducive supporting flange (8), and a transition flange (9). Through the integration of a full-fiber current transformer and an isolation-type circuit breaker, the current transformer simplifies the main power line while completing the measurement of an external current, reduces the occupied space, and improves the stability of a power grid. In addition, the polarization maintaining fiber (6) in the full-fiber current transformer is embedded into the fiber composite bushing (4) which is used for supporting the isolation-type circuit breaker, so there is no need of other insulating connection parts. The current transformer is simple and reliable in insulation, and is high in integration degree. Compared with a conventional current transformer, the current transformer is high in accuracy, is large in measurement range, and is good in transient characteristics.

The invention discloses a dynamic PID global sliding mode control method of a micro gyroscope neural network. A neural network dynamic PID global sliding mode control system comprises a dynamic PID global sliding mode controller and a neural network uncertainty estimator. Global sliding mode control can overcome the disadvantage that the mode state in the traditional sliding mode control does not have robustness, quickens the system response, and ensures that the system has robustness during the whole response process. According to the method, an integral item is introduced in the design of sliding mode surface, so as to restrain steady state error and improve robustness, moreover, dynamic sliding mode control can reduce buffeting phenomenon, so that the combination of PID global sliding mode and dynamic sliding mode can develop respective advantages at the same time, improve the transient performance and the robustness of the sliding mode control system and reduce the frequency of buffeting during sliding mode variable structure control.

The invention relates to a partial P-type GaN cap layer RESURF GaN-based schottky barrier diode which is characterized by comprising a substrate layer, a buffer layer arranged on the substrate layer,a channel layer arranged on the buffer layer, a barrier layer arranged on the channel layer, a cathode and a composite anode which are arranged on the two ends of the barrier layer, a partial P-type GaN cap layer which is connected with the composite anode and arranged on the barrier layer, and a passivation layer which covers the barrier layer, the partial P-type GaN cap layer, the composite anode and the cathode. The channel layer and the barrier layer form heterojunctions. The P-type GaN cap layer and the barrier layer form PN junctions. The cathode is cathode ohmic contact. The composite anode comprises anode ohmic contact and anode schottky contact. The partial P-type GaN cap layer is introduced and the composite anode is used so as to prepare the GaN-based schottky barrier diode having low forward starting voltage and high reverse breakdown voltage.