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.

The invention discloses a multi-DC motor forward series control system and method, wherein 2*(n+1) IGBT modules are connected in series in pairs to form n+1 bridge arms; the n+1 bridge arms are connected in parallel with positive and negative poles of a DC power supply, and n DC motors which are serially connected in a forward manner are respectively connected in series with the n+1 bridge arms; the n DC motors are connected to a reference voltage synthesizer through two-stage PI controllers via a speed sensor, a current sensor and a speed adjustment module in sequence, and the reference voltage synthesizer is connected to n+1 phase inverters by a PWM pulse generating unit; the n+1 phase inverters are connected to the reference voltage synthesizer via current regulating modules and one-stage PI controllers, and are connected to the PWM pulse generating unit through the reference voltage synthesizer; and pulse control signals generated by the PWM pulse generating unit control the on/offof the 2*(n+1) IGBT modules to drive the n DC motors. The number of circuit elements is small, the structure is simple, the performance stability is reliable, and the wide use value is achieved.

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 discloses a double salient generator voltage adjustment control device and method having anti-interference capability. The method is characterized by, establishing a third-order linear state observer through detecting the output voltage of a generator and establishing switch tube control rata of a voltage regulator by utilizing output voltage reference values and linear state observer parameters, thereby realizing prediction correction of the output of the generator, improving dynamic response of the generator, reducing static difference, realizing auto-disturbance rejection function and overcoming the defects in the conventional control technology. The realization of the control method needs the combination of related hardware circuits. The required hardware circuits are simple in structure; the control method finishes related algorithms mainly by depending on a microprocessor; the overall used devices in the scheme are few; the production cost is low; and the device and method have extremely-high disturbance rejection performance and output voltage static difference.

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 control system and method with three direct-current motors in forward-direction serial connection. The system is characterized in that eight IGBT modules form four bridge arms in a two-two serial connection manner, the four bridge arms are parallelly connected to the positive electrode and the negative electrode of a direct-current power supply, the three direct-current motors in forward-direction serial connection are serially connected with the four bridge arms, the three direct-current motors are connected with a reference voltage synthesizer sequentially through aspeed sensor, a current sensor, a speed adjusting module and a secondary PI controller, the reference voltage synthesizer is connected with a four-phase inverter through a PWM pulse generating unit,the four-phase inverter is connected with the reference voltage synthesizer through a current adjusting module and a primary PI controller, the four-phase inverter is connected to the PWM pulse generating unit through the reference voltage synthesizer, and pulse control signals generated by the PWM pulse generating unit controls the on and off of the eight IGBT modules to drive the three direct-current motors to operate. The control system is few in used circuit components, simple in structure, stable and reliable in performance and worthy of popularization and application.

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 PI controller design method capable of preventing integral saturation during aero-engine control strategy switching, and relates to PI controller design of multiple control strategies of high-pressure rotating speed closed loop control, exhaust temperature closed loop limit, low-pressure rotating speed closed loop limiting, gas compressor outlet pressure closed loop limiting, acceleration closed loop limiting, deceleration closed loop limiting and the like and switching of all the control strategies. All closed loop controllers adopt a manner that a deviation is multiplied by a proportional action coefficient, then added with a fuel oil flow given value at the previous time and multiplied by a first-order inertia link transfer function, the fuel oil flow given values of all the control strategies at the current moment begin to be calculated from the fuel oil flow given values selected from the previous moments, large deviations of the non-selected control strategies cannot be accumulated, integral saturation cannot appear, however, substantially, it is still a PI controller, an integration element is included, and similarly, the offset can be removed.

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.