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476results about How to "Reduce overshoot" patented technology

Self-disturbance control method for permanent magnet synchronous motor

The invention provides a self-disturbance control method for a permanent magnet synchronous motor, and belongs to the technical field of permanent magnet synchronous motor control. The method comprises the steps of: designing a hyperbolic tangent function expansion state observer, adopting the saturation characteristics itself of the hyperbolic tangent function to effectively suppress a differential peak appearing in a traditional expansion state observer so as to improve the system control performance. The non-linear feedback control rate based on the new adaptive sliding mode control is proposed which is characterized by designing a new adaptive shifting index approach law which introduces a first-order norm of the state variable, and an approaching speed is adaptively regulated according to the distance of the state variable from the balance point to reduce the dependence of the self-disturbance control on the parameter robustness so as to achieve the high-precision and high robustness control of a permanent magnet synchronous motor. When the system is disturbed and a load fluctuates, the rotation speed is rapidly tracked, the response speed of the system is improved, the systemovershoot and the steady state static difference are reduced, and the system robustness is greatly enhanced.
Owner:JIANGSU UNIV

Low dropout linear voltage regulator (LDO) without off-chip capacitor for improving transient response and increasing power supply rejection ratio (PSRR)

The invention relates to a low dropout linear voltage regulator (LDO) without an off-chip capacitor for improving transient response and increasing power supply rejection ratio (PSRR). The LDO without the off-chip capacitor comprises an error amplifier, a reference voltage source module, a power adjusting tube, an NMC Miller's compensating circuit, a PSRR enhanced network and a transient response intensifier circuit. According to the LDO without the off-chip capacitor, the NMC compensation technique is used for meeting the system stability requirement; a second-stage gm improved circuit of the amplifier is used for increasing the charging and discharging currents to the grid of the power tube; a slew rate intensifier circuit is introduced, needed currents can be provided for a load when the load of the LDO is subjected to step hopping from small to large, and thus the transient response capacity of the LDO is improved under the double actions. In addition, the PSRR enhanced network is additionally arranged to be used for controlling the PSRR feedback factors beta of the system, an original zero point is pushed to the position with higher frequency, and therefore the PSRR characteristic of the system is improved. The LDO without the off-chip capacitor is improved on the aspect of transient response and the aspect of PSRR.
Owner:JILIN UNIV

Two-position three-way inverse proportion decompression electromagnetic valve for AT (Automatic Transmission)

The invention relates to a two-position three-way inverse proportion decompression electromagnetic valve for an AT (Automatic Transmission). The two-position three-way inverse proportion decompression electromagnetic valve is mainly formed by a main valve and a proportion electromagnet, wherein the main valve is formed by a valve body, a valve core which is positioned at the inner part of the valve body, a valve seat which is sleeved on the valve body and an inner valve core which is positioned at the inner part of the valve core and close to one side of the valve seat, and the proportion electromagnet is formed by a sliding bearing, a bearing seat, a pole shoe, an armature, a top rod, a stroke gasket, a stop iron, a spring seat, a regulating spring, a baffle plate, a regulating screw, a baffle plate cushion, a coil and a yoke iron. According to the two-position three-way inverse proportion decompression electromagnetic valve disclosed by the invention, the problems such as lower response speed, larger pressure fluctuation, short service life, large leakage rate and high manufacturing cost of an existing inverse proportion decompression electromagnetic valve for the AT are solved, and the two-position three-way inverse proportion decompression electromagnetic valve disclosed by the invention has the advantages of high response speed, small pressure fluctuation, long service life , small leakage rate, lower manufacturing cost and the like.
Owner:兰溪市中元贸易有限公司

Gallium-nitride-based light emitting diode capable of improving electron injection efficiency

The invention discloses a gallium-nitride-based light emitting diode capable of improving electron injection efficiency. The gallium-nitride-based light emitting diode comprises a substrate, a gallium nitride nucleation layer, a buffer layer, an n-type contact layer, a lower multicycle n-type electron coupling layer, a lower tunneling potential barrier layer, an upper multicycle n-type electron coupling layer, an upper tunneling potential barrier layer, a multicycle active luminous layer, a negative electrode, a p-type electron blocking layer, a p-type contact layer and a positive electrode, wherein the gallium nitride nucleation layer is manufactured on the substrate; the buffer layer is manufactured on the gallium nitride nucleation layer; the n-type contact layer is manufactured on the buffer layer; a table top is formed on one side of the upper surface of the n-type contact layer; the lower multicycle n-type electron coupling layer is manufactured on the other side of the table top on the n-type contact layer; the lower tunneling potential barrier layer is manufactured on the lower multicycle n-type electron coupling layer; the upper multicycle n-type electron coupling layer is manufactured on the lower tunneling potential barrier layer; the upper tunneling potential barrier layer is manufactured on the upper multicycle n-type electron coupling layer; the multicycle active luminous layer is manufactured on the upper tunneling potential barrier layer; the negative electrode is manufactured on the table top of the n-type contact layer; the p-type electron blocking layer is manufactured on the multicycle active luminous layer; the p-type contact layer is manufactured on the p-type electron blocking layer; and the positive electrode is manufactured on the p-type contact layer to form the structure of the gallium-nitride-based light emitting diode.
Owner:INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI

Large-scale open channel water level automatic control method based on storage capacity dynamic regulation

The invention relates to a large-scale open channel water level automatic control method based on storage capacity dynamic regulation. The method comprises the steps of determining a feed-forward flow regulating value; determining whether the feed-forward flow regulating value needs to be subjected to feedback correction or not; calculating a feedback correction value of a feed-forward control flow; calculating a flow regulation target value; calculating the actual opening of a gate; adjusting the opening of the gate. The method disclosed by the invention adopts a feed-forward flow control mode and fully considers the influences of division flow and water level dead areas for controlling a water surface profile of the whole channel section, so that water level fluctuation at local points can be flattened and filtered out, the sensitivity to movement dead areas of the gate is reduced, and accordingly frequent operation for the gate is reduced. Storage capacity compensation conditions required by stable water delivery are conveniently realized, so that the phenomenon of water level overswing is effectively reduced, and stability can be more quickly realized. The control principle is simple and clear and easy to realize and grasp, the influences of various disturbance factors can be effectively avoided, the operation and management cost of an open channel is reduced, the water delivery safety is ensured, and the water delivery efficiency is improved.
Owner:CHINA INST OF WATER RESOURCES & HYDROPOWER RES

Permanent magnet synchronous motor current increment prediction algorithm

ActiveCN103516284AImprove current dynamic performanceImprove current dynamic response speedElectronic commutation motor controlVector control systemsPrediction algorithmsPermanent magnet synchronous motor
The invention relates to a permanent magnet synchronous motor current increment prediction algorithm which comprises the following steps: (1) a stator d shaft voltage equation and a stator q shaft voltage equation of a permanent magnet synchronous motor in a synchronous rotating reference frame are established; (2) according to the stator q shaft voltage equation in the step (1), discrete voltage equations of the permanent magnet synchronous motor are established in the current period and the previous period respectively; (3) changes in voltage items relevant to rotating speed are ignored, and the discrete voltage equations of the permanent magnet synchronous motor are subtracted to obtain a current increment formula of the permanent magnet synchronous motor; (4) a pulse transfer function between a current predicted value and a current detected value in the current period is obtained according to a transfer function of the permanent magnet synchronous motor and the current increment formula of the permanent magnet synchronous motor; (5) a closed loop pulse transfer function of a q shaft current loop by means of the current increment prediction algorithm is obtained according to the pulse transfer function, a pulse transfer function of a traditional current loop PI regulator, and the transfer function of the permanent magnet synchronous motor. The permanent magnet synchronous motor current increment prediction algorithm can be widely applied to the field of permanent magnet synchronous motor servo control.
Owner:TSINGHUA UNIV
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