37results about How to "Eliminate static difference" patented technology

The invention provides a virtual synchronous generator-based shore power source system stability control method comprising an active power-frequency control part and a reactive power-voltage control part, virtual inertia control consists of virtual machinery rotational inertia J[omega]0s and machinery damping D[omega]0, a control equation for active power-frequency control P-f is indicated in the description, and a stability control equation for reactive power-voltage control Q-U is indicated in the description. Via the method, a problem of steady state deviation of system frequency in a current VSG technology-based shore power source can be overcome, static difference of system frequency can be eliminated, violent fluctuation of system voltage caused by reactive power rush of ship loads can be effectively checked because a link of reactive power inertia control and virtual excitation control is added in a traditional reactive power-voltage control strategy, and static difference of the system voltage can be eliminated. Via the control strategy disclosed in the invention, automatic power distribution can be realized during parallel operation of high capacity multi-module shore power sources.

A vehicle power matching system with a hydraulic mechanical continuously-variable transmission can automatically adjust the transmission ratio of the transmission according to driving intentions of drivers and changes of an external load so that a driving system can provide enough power when in a transient state; during the transient state, an engine works at an optimal economical curve, and accordingly the system performance can be optimal. The vehicle power matching system has the advantages that the engine always works under the working conditions of optimal power performance and optimal economy; infinitely variable speeds are achieved rapidly and stably under the conditions of the driving intentions of the drivers and the changes of the external load; during the process, vibration noise is small, the overshoot is small, and offset is eliminated as far as possible; and the vehicle power matching system can meet the transient state power performance requirements and steady state economy requirements when a vehicle runs.

The invention provides a compensation method and device for the rotor position of a permanent magnet synchronous generator. The compensation method comprises the steps of dividing the rated power of the generator into N segments to obtain N power interval sections; for each power interval section, when the difference between the output active power of the generator and an active power set value ofthe generator in the corresponding power interval section is less than a first preset threshold, estimating the rotor position of the power interval section; applying offset to the estimated rotor position of each power interval section, and correspondingly obtaining an active power value of each power interval section after the rotor position with the applied offset is obtained, wherein the active power value includes a converter network side port active power output value or a generator active power output value; determining the optimal rotor position offset of each power interval section according to each active power value in the power interval section; and compensating the estimated rotor position of the power interval section according to the optimal rotor position offset.

The invention discloses a vertical pulverizer for grinding ultrafine powder. The vertical pulverizer for grinding ultrafine powder comprises a mechanical mechanism and a hydraulic mechanism, wherein a proportional valve control amplifier (16) of the hydraulic mechanism comprises an input interface unit (18) connected with an electric controller (17); the input interface unit (18) is connected with a signal processing unit (19); the signal processing unit (19) is connected with a power amplifying unit (20) connected with a proportional speed regulating valve (15); the proportional speed regulating valve (15) is provided with a displacement sensor (21) connected with a signal conditioning circuit (22); the signal conditioning circuit (22) is connected with the signal processing unit (19). The vertical pulverizer for grinding ultrafine powder, which is provided by the invention, can effectively prevent equipment failure caused by motor overloading; meanwhile, the hydraulic mechanism provided by the invention has superior stability and reliability, and the powder fineness and consistency after grinding are very ideal.

The invention belongs to the technical field of submarine falling depth retrieval control, and particularly relates to a method for retrieving falling depth of an X-rudder submarine. The method comprises the following steps: establishing a moving coordinate system by taking the center of gravity of the submarine as an original point, constructing a six-degree-of-freedom spatial motion equation ofthe cross rudder submarine, constructing an X rudder control force equation, and constructing a six-degree-of-freedom spatial motion equation of the X rudder submarine; iteratively solving a six-degree-of-freedom spatial motion equation of the X-rudder submarine by utilizing a four-order Runge-Kutta method; constructing a head rudder fuzzy controller and an X rudder fuzzy controller, determining acorresponding rule of X rudder manipulation, and constructing a steering fuzzy rule. The deepened depth retrieval efficiency of density mutation 0.5% is obviously improved; meanwhile, in combinationwith the scheme of longitudinal inclination auxiliary retrieval, the beneficial effect of the hull posture on depth drop retrieval is effectively utilized, the severe depth drop with the density abrupt change of 1% can be successfully retrieved, the pressure of the first rudder is relieved through longitudinal inclination auxiliary, the first rudder has the capability of continuing to operate, andthe retrieval success rate is effectively guaranteed.

The invention discloses a control method and a control device for rapid constant temperature of a PCR (Polymerase Chain Reaction) detector and the PCR detector, in the control method for rapid constant temperature of the PCR detector, an integral separation method is operated in the whole process, and when the output quantity is 0 lt; and utt; when umax is greater than or equal to umax, integral is introduced, PID control is adopted, and when ut is greater than or equal to umax or ut is less than or equal to 0, PD control is adopted. In the temperature changing stage, a time optimal PID control algorithm and a traditional PID control algorithm are adopted for heating or cooling; a traditional PID control algorithm is adopted in the constant temperature stage; at a variable-temperature and constant-temperature switching time point, a temperature fast-setting control algorithm and a self-adaptive control algorithm are adopted; the method has the advantages of being accurate in temperature control, excellent in temperature change benefit, fast in temperature change, fast in constant temperature and small in overshoot, it can be guaranteed that the target value can be reached at the fastest speed, the time needed by the temperature rising stage and the temperature falling stage is shortened, and oscillation and overshoot of temperature waveforms of PCR in the circulation section are reduced.