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

The invention discloses a hydraulic control system for a constant pressure press for a timber floor. The hydraulic control system for the constant pressure press for the timber floor comprises a mechanical mechanism and a hydraulic mechanism; a proportional control amplifier (16) of the hydraulic mechanism comprises an input interface unit (18) connected with a pressure sensor (17); the input interface unit (18) is connected with a signal processing unit (19) connected with a power amplifying unit (20); the power amplifying unit (20) is connected with a proportional speed regulation valve (15) provided with a displacement sensor (21); the displacement sensor (21) is connected with a signal conditioning circuit (22); the signal conditioning circuit (22) is connected with the signal processing unit (19). Multiple timber floor manufacturing procedures are integrated, so the manufacturing process is greatly simplified, the production efficiency is improved and manpower is saved; the hydraulic control system can be industrially produced, so the product consistency can be ensured.

Disclosed is a high-precision phase locking method for an intelligent integrated low-pressure reactive power module, the method comprising a multiplicative phase discrimination link (1), a variable frequency period integration link (2), a variable parameter integration separation speed change PI regulation link (3), an angular frequency integration link (4), a frequency estimation link (5), remainder (6), sine (7) and cosine (8). An improved PI regulator uses a variable parameter integration separation speed change PI regulator for regulation, so that the phase locking precision is improved and the static deviation is eliminated under the premise that the rapidity of phase locking can be ensured. An improved loop filter can eliminate the influence of harmonic wave and frequency changes on the output precision of a phase-locked loop when in a steady state.

The invention discloses a hydraulic control system for log cutting machines. The hydraulic control system comprises a mechanical mechanism and a hydraulic mechanism, wherein the mechanical mechanism comprises a cutting piston (1); a cutting cutter head (2) is arranged at the extension end of the cutting piston (1); the cutting cutter head (2) is driven by a motor (3); the hydraulic mechanism comprises a proportional velocity regulating valve (6) which is connected to an oil way B; the signal output end of the proportional velocity regulating valve (6) is connected with a proportional valve control amplifier (8) through a circuit; the proportional valve control amplifier (8) is connected with an electric controller (7); the electric controller (7) is connected with the motor (3) through a circuit. According to the hydraulic control system for the log cutting machines, the cutting efficiency of the cutting machines can be improved and the equipment failure caused by overload can be also avoided.

The invention discloses a double salient generator voltage regulation control device and method with anti-disturbance capability. By detecting the output voltage of the generator, constructing a third-order linear state observer, and using the output voltage reference value and the parameters of the linear state observer to establish the control rate of the switching tube of the voltage regulator, the prediction and correction of the generator output is realized, and the generator is improved. The dynamic response reduces the static error, realizes the self-disturbance rejection function, and overcomes the shortcomings of the traditional control technology. The realization of the control method of the present invention needs to be combined with relevant hardware circuits. The required hardware circuit structure is simple, and the control method mainly relies on the microprocessor to execute related algorithms. The overall scheme uses fewer devices, lower production costs, and has strong anti-disturbance performance. and output voltage static difference.

The invention discloses a PI controller design method for preventing integral saturation in aero-engine control strategy switching, and relates to closed-loop control of high-pressure rotational speed, closed-loop limitation of exhaust temperature, closed-loop limitation of low-pressure rotational speed, closed-loop limitation of compressor outlet pressure, and closed-loop limitation of acceleration The PI controller design of multiple control strategies such as deceleration closed-loop limit and the switching of each control strategy, each closed-loop controller adopts the deviation multiplied by the proportional action coefficient plus the fuel flow given value at the previous moment multiplied by the first-order inertial link In the form of transfer function, the given value of fuel flow of all control strategies at the current moment is calculated from the given value of fuel flow selected at the previous moment, and the large deviation of the unselected control strategy will not be accumulated, and integral saturation will not occur , but it is still a PI controller in essence, including an integral link, which can also eliminate static error.

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 closed-loop control method and system based on traditional VSR current closed-loop control, belonging to the field of power electronics and its control technology; thesteps of the present invention are as follows: 1. The DC bus voltage of the rectification side is an outer ring, and the PI is passed through the PI. Adjusting to obtain the given value of the outputactive power; 2. Obtaining the given set value and the reactive power set value through the current command calculation module to obtain the active current command value and the reactive current command value; 3. The obtained active current The command value and the reactive current command value are adjusted by the current loop to obtain two values; 4. The two values are converted into a two-phase [alpha][beta] stationary coordinate system by synchronous coordinate transformation, and two other values are obtained; 5. Through SVPWM Generate six PWM signals to control VSR operation. The invention adds a new method for calculating the current command, thereby overcoming the problem that the dynamic response of the vector control strategy of the traditional VSR current closed loop is slow,the total harmonic distortion rate of the grid current is large, and the anti-interference performance to disturbance such as load variation is poor.