34results about How to "Improved current control performance" patented technology

The invention discloses a current control method of a permanent magnet motor servo system, which belongs to the technical field of power generation, power transformation or power distribution. In this method, the three-phase current at time k is obtained by sensor sampling, and the Park and Clark transformation is performed to obtain the dq-axis current in the rotating coordinate system, and then the dq-axis current value is predicted at the next time through the dq-axis current, and the predicted current value at time k is The current value sampled at time k is weighted and then averaged to obtain the corrected current value at time k. The corrected current value at time k is used to further predict the voltage value of the dq axis at the next time, and then the voltage value of the αβ axis is obtained by inverse park transformation. Combined with the DC side voltage of the three-phase inverter, the conduction sequence of the switch tubes is controlled by space vector pulse width modulation, and then the control of the motor is realized, which can suppress the influence of the sampling error on the current control in the steady state process.

The invention relates to an angle-type STATCOM based on feedforward control of power grid voltage and a control method of the angle-type STATCOM. The control method comprises steps of superposing output quantity of a feedforward controller on the output quantity of a current inner ring, and judging whether the power grid is in a steady state or in a transient state before the STATCOM is unlocked; if the power grid is in the steady state, using a feedforward item based on power grid voltage phase angle compensation as the output quantity of the feedforward controller, and after a control system is stable, switching to take the feedfoward item based on direct acquisition of power grid voltage as the output quantity of the feedforward controller; and if the power grid is in the transient state, using the feedfoward item based on direct acquisition of power grid voltage as the output quantity of the feedforward controller. According to the invention, it can be achieved that the impact current is smallest during unlocking under the condition that the power grid is in the steady state; based on the feedforward item of the power grid voltage, true conditions of the power grid voltage can be well reflected under the condition that the power grid is in the transient state; the smaller the sampling delay time of the power grid voltage is, the smaller the delay time of the control system is; and excellent current control performance can be acquired. Thus, by combining advantages and avoiding the disadvantages of two kinds of the feedforward items, the performance of the STATCOM is improved.

The invention relates to a sensorless model predictive control system and a method of a permanent magnet synchronous motor for vehicles. The system comprises a maximum torque-current ratio controllerfor obtaining a reference value of a stator current; Stator current feedback module: acquiring a stator current feedback value; A position observer module for observing the rotational speed and the rotor position angle of the permanent magnet synchronous motor; A current predictive control module, which performs current predictive control according to the stator current reference value, the statorcurrent feedback value, the speed of the permanent magnet synchronous motor and the rotor position and outputs a stator voltage reference value; A rotating high-frequency voltage injection module that generates a rotating high-frequency voltage signal and superimposes the rotating high-frequency voltage signal and a stator voltage reference value to obtain a control voltage; SVPWM modulation module: SVPWM modulation of the control voltage to obtain inverter control signal, inverter connected to the permanent magnet synchronous motor. Compared with the prior art, the invention not only can realize the optimization of the current control performance, but also can simplify the controller hardware and improve the reliability of the control system.

A method for controlling the excitation current of a solid stator maglev, including the following steps: (1) Establishing an excitation current control system with FO[PI] as the core controller; (2) Deriving the mathematical model of the controlled object; (3) According to the fractional order Calculus theory, to further deduce the amplitude and phase characteristics of the controlled object; (4) deduce the amplitude and phase characteristics of other parts of the control system; (5) obtain the amplitude and phase characteristics of each link in the control system through the above steps, and comprehensively get the whole Control the amplitude and phase characteristics of the open-loop transfer function of the system; (6) Simultaneous equations, solve the three control parameters Kp, Ki, and λ in the controller to obtain ideal current control performance; according to the designed cut-off frequency, stable The margin and the phase angle conversion rate of the cutoff frequency are zero to solve the controller coefficients. The obtained control system has better control performance than the traditional PI controller, and is more suitable for the current control of the magnetic levitation system with a solid stator structure.

The invention discloses a current prediction control method of a dual-winding induction generator system, which relates to the technical field of induction motor drive control. Taking a five-phase dual-winding induction generator system as an object, a PI regulator is used to control the control winding side and the power winding of the induction generator system. The side bus voltage is calculated by using the voltage model rotor flux linkage to obtain the rotor flux linkage amplitude and orientation angle, and the current prediction model of the dual-winding induction generator system is established. By controlling the winding current and the rotor flux linkage amplitude, the current prediction model is calculated In the next control cycle, the predicted value of the control winding current is set to keep up with the given value, and the required control winding voltage is calculated and sent to the space vector pulse width modulation to output the switch signal. The current predictive control method is simple to implement, effectively overcomes the problem of difficult parameter setting in the traditional method, and has better current control performance, thereby improving the dynamic performance of the entire control system.

The embodiment of the invention discloses a method for improving low-gray-scale color shift and an OLED display panel. The method includes the steps: setting a first lighting rule for setting a pixelunit by using a first brightness value in a set time period in each refresh cycle of the OLED display panel in any low gray state, and controlling the OLED panel for display by using the first lighting rule. Since the first brightness value for lighting the pixel unit in the first lighting rule is greater than a second brightness value for lighting all the pixel units in the entire refresh cycle and an OLED is a current-driven device, the brightness of the pixel unit is increased when the first lighting rule is used for controlling the display of the OLED display panel, the control current ofa TFT is also increased accordingly. Since the current control capability of the TFT is enhanced, the impact of a leakage current of the TFT on the color shift is also decreased, thereby effectively solving the problem of low-gray-scale color shift of the OLED display panel.