63 results about "Plus integral" patented technology

The invention provides a maximum power tracking control method of a voltage variable photovoltaic system which adapts to weather conditions, belonging to the photovoltaic power generation technical field; firstly, three data of voltage, current outputted by a photovoltaic battery and temperature of a photovoltaic battery plate at a moment are collected by a collection circuit, and an open circuit voltage value and an illuminating value at the moment are worked out based on the collected data; secondly, an approximate optimum output voltage value is obtained by a real optimized voltage coefficient multiplying the open circuit voltage value, and the temperature and the illumination are compensated, which obtain a real optimum output voltage value, and further a real optimum output current value is obtained; thirdly, an output value of a load end is compared with the real optimum output voltage value and the real optimum output current value, and a maximum power output is realized based on the proportional plus integral control on a fluctuating chopper circuit and a double closed loop of the voltage and the current. The maximum power tracking control method of the voltage variable photovoltaic system improves the output power of a photovoltaic power generation system and simultaneously ensures the operational stability and reliability of the system.

The invention provides a maximum power point tracking method based on efficient adaptive perturbation and observation. By the aid of the maximum power point tracking method, the problem that the step size used in a traditional perturbation and observation method in the photovoltaic-battery maximum power point tracking technology is difficult to balance, completely adaptive perturbation can be realized, and tracking speed, stability precision and universality of a system are high. The maximum power point tracking method with a basic principle includes that computing continuous output power values of a photovoltaic array according to filtered voltage and current signals; generating error signals according to changes among power signals; generating adaptive perturbation voltage values via a PI (proportional plus integral) controller; and finally generating a reference value of voltage of the photovoltaic array according to the basic principle of perturbation and observation. An error signal of an actual value and the reference value of the voltage of the photovoltaic signal is computed, and a duty cycle signal d required by a DC/DC converter is generated by another PI controller, so that on and off time of each power switch tube of a phase-shift full-bridge converter is controlled, power outputted by the photovoltaic array is adjusted, and the maximum power output point of the photovoltaic array can be tracked.

The invention discloses a neutral network theory-based non-linear system adaptive proportional integral control method. The method comprises the following steps: in a first step, a mathematical model for a non-linear system is built; in a second step, a smooth function is used for approximating a non-smooth performer saturation function; in a third step, a neutral network adaptive proportional plus integral controller is designed for control. According to the method disclosed in the invention, as for a non-linear system with input saturation, the smooth function is used for approximating the performer saturation function, a BLF is referenced, that neutral network input is maintained in a bounded compact set range can be ensured, and normal operation of a neutral network can be ensured; compared with a conventional PI gain adjustment, an adjustment method put forward in the invention is advantageous in that 1) proportion integral gain of the PI controller is not a fixed constant but a time variant; 2) proportional gain and integral gain are not designed individually but associated with each other via a certain coefficient, and therefore system analysis can be facilitated; 3) the method has certain robustness for nondeterminacy and input saturation of the system.

The invention provides an engine cooling system control method and system and a vehicle. The control method comprises the steps of acquiring the actual water temperature, rotating speed and load of anengine, determining the target water temperature of the engine according to the rotating speed and the load of the engine, calculating the deviation value of this time between the target water temperature and the actual water temperature and obtaining the deviation change rate according to the deviation value of this time and the deviation time of last time, obtaining a feed-forward signal used for adjusting the opening degree of a ball valve according to the target water temperature, determining a proportional plus integral control feedback signal for adjusting the opening degree of the ballvalve according to the deviation value of this time and the deviation change rate, obtaining an opening degree adjusting signal according to the feed-forward signal and the feedback signal and adjusting the opening degree of the ball valve according to the opening degree adjusting signal. By means of the engine cooling system control method, rapid and accurate control over the water temperature of the engine can be realized; and accordingly, the performance of the engine is improved, and duel consumption is reduced.

The invention discloses a method of controlling a three-phase inverter and a device thereof. The device comprises a three-phase three-leg inverter bridge consisting of six power switch tubes, an output filter circuit including a three-phase filter reactor and a three-phase filter capacitor and a main circuit consisting of a three-phase boosting/decompression isolation transformer Delta/Y; a load voltage is processed through phase-separation PI proportional plus integral control; the three-phase inverter is led to keep the balance of three-phase output voltage under any linear or nonlinear unbalanced load. When in unbalanced load, symmetrical output voltage of the three-phase inverter, the equivalent three-phase magnitude, orthoscopic voltage waveform and high output voltage quality can be kept all the time, and the load is enabled to work normally.

The invention discloses a control method of a self-balancing man-riding electric unicycle. The method includes: acquiring data from an accelerator and a gyroscope disposed on the unicycle, subjecting the acquired data to Kalman filtering to obtain current tilt angle and tilt angular velocity of the unicycle, acquiring a given motor speed value through a nonlinear PD (proportional plus derivative) controller, acquiring a given torque current value from a difference between the given motor speed value and a currently measured motor speed fed-back value through a PI (proportional plus integral) controller, acquiring a drive signal through vector control, and allowing a motor to output a proper torque to keep the unicycle balanced. The control method has the advantages that a control strategy features good dynamic and static properties, system vibration and noise are reduced, and the unicycle is allowed to self-balance the attitude and to carry a man riding.

A method of measuring a motor constant is provided in a vector control apparatus for an induction motor. A voltage output phase θv is set at a previously set arbitrary phase. Prior to applying a current, a current command is fed to operate the vector control apparatus with a proportional-plus-integral controller being set operative. After conduction for a predetermined time, the gain of the proportional-plus-integral controller is set to zero to maintain an integrated value constant and accordingly fix a voltage command value. In this state, a current command value and a detected current value are measured. This measurement is performed at two levels of current, and a primary resistance value (or a line-to-line resistance value) is derived from the slope.

The invention discloses an STATCOM current tracking and compensation method. The method includes processing a three-phase voltage and a three-phase current which are gathered at point P, obtaining a transfer matrix as well as active current components and reactive current components of the current which needs to be compensated by a system, processing the current gathered by load side through transformation from a coordinate abc to a coordinate dq and a low pass filter, obtaining direct current components on q axis of the STATCOM reference current, outputting the direct current components as active components of the reference current in the voltage proportional integral cycle of the STATCOM direct current capacitance and voltage, controlling the active components and reactive components of the compensated current through fuzzy proportional plus integral (PI) control, producing control signal through the technique of space vector pulse width modulation (SVPWM), and controlling the output of STATCOM. The STATCOM current tracking and compensation method has the advantages that influence on STATCOM performance caused by asymmetry of the three-phase voltage of the system is overcome, current needed to be compensated by the system is detected accurately, and the current needed to be compensated by the system is tracked and compensated quickly and effectively.

The invention relates to a permanent magnet synchronous machine control system based on a high-order sliding mode method. The system is characterized by comprising the components of a Cark transformation module, a Park transformation module, a rotary transformer, a high-order sliding mode observer, a two-order supercoiling sliding mode controller, a first comparator, a second comparator, a permanent magnet synchronous motor d-axis current loop proportional plus integral controller, a permanent magnet synchronous motor q-axis current loop proportional plug integral controller, a Park inverse transformation module, a pulse width modulation module and an inverter. The permanent magnet synchronous machine control system can quickly and effectively adjust various input parameters and output parameters of the permanent magnet synchronous motor on the condition that an interference occurs, and furthermore realizes high dynamic response speed and high robustness. Furthermore the permanent magnet synchronous machine control system improves control precision and operation reliability of the permanent magnet synchronous machine.

The invention discloses a double-resonance injection type broadband impedance measuring device and a control method thereof. The measuring device comprises a current disturbance injection unit, a signal processing unit and a broadband impedance calculation and monitoring unit; each phase of the current disturbance injection unit is cascaded with 6 sub-power module units; the output of each phase of the current disturbance injection unit is connected into a system to be tested through a disturbance injection branch; and the disturbance injection branch combines the advantages of a series resonance branch and a parallel resonance branch, and therefore, a cascade power module can withstand a small fundamental voltage, most of disturbing current is injected into the system to provide a currentdisturbance source. According to a cascaded H-bridge converter, a voltage outer loop adopts proportional plus integral control, and a current inner loop adopts quasi-proportional resonance control; and the turning on and turning off of the power devices of H-bridge converters in each phase are controlled through carrier phase-shift SPWM multilevel modulation. With the control method adopted, thesystem has higher reliability and faster dynamic response and can meet the requirements of the application of the system to megawatt-level high-power conditions and wideband disturbance output impedance measurement.

The invention discloses a predictive control-based permanent magnet synchronous motor composite current control system and method. According to the system and method of the invention, the actual angular speed omega of a motor and the given reference rotational speed omegar of the motor, adopted as variables, are inputted to a PI rotational speed loop control module; the PI rotational speed loop control module calculates the difference of the actual angular speed and the reference rotational speed; by means of the proportional plus integral action of a rotational speed loop, the output currenti<*>q of the module is adopted as a q-axis reference current value; the three-phase output current of the motor is subjected to Clark transformation, the current of the motor in a two-phase stationaryalphabeta coordinate system is obtained, and the current is subjected to Park coordinate transformation, so that two-phase current under a dq rotating coordinate system is obtained; and reference current under a motor dq coordinate system and the two-phase current under the dq rotating coordinate system are inputted to a predictive current controller. According to the system and method of the invention, deadbeat predictive control and equivalent interference input are adopted. The current controller of the method can be applied to a PMSM torque or rotational speed driving system, has high current tracking performance and can quickly adjust the system when the system is subject to disturbance, so that the system will not be affected by a variety of disturbance factors.

An exemplary temperature control system for animal confinement buildings includes an agricultural heater and a ventilation system. The agricultural heater is modified to be a variable rate heater using SmartBox technology or by applying appropriate control logic and outputs to a conventional room controller. A heat on/off relay of the room controller can serve as an enable signal connected to the SmartBox. Heating is controlled using a proportional-plus-integral algorithm for error correction. Error correction may be ceased when temperatures fall within a dead band. Heat is turned on when the temperature drops to an on temperature equal to a set point minus 0.5 F. Heat can be turned off when the heater has been at a minimum output level for a minimum output period (such as 90 seconds) and the temperature has not dropped below the on temperature during the minimum output period. An auto-variable radiant brooder may be incorporated.

The invention discloses a valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method. The valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method comprises the steps that a position command signal r is input; a pressure difference signal p of two cavities of a hydraulic cylinder and an acceleration signal a of a piston rod of the hydraulic cylinder are used as input signals of a disturbing force calculation module to obtain the disturbing force F; the disturbance compensation signal x2 is calculated; the position command signal r is used for subtracting the a displacement signal c of the piston rod of the hydraulic cylinder, and the difference between the position command signal rand the displacement signal c are used as input signals of a proportional plus integral controller; an output signal x1 of the proportional plus integral controller is added to a disturbance compensation signal x2 to obtain a drive signal x of a servo valve, and the drive signal x is input to a valve-controlled cylinder system to drive the hydraulic cylinder and the load to generate the corresponding movement. According to the valve-controlled cylinder electro-hydraulic position servo system low-frequency interference compensation method, the fluctuation of the amplitude-frequency characteristic of closed loop transfer function of system location within the 6-7hz band can be reduced to within 3dB, and control precision of the system is significantly enhanced. The valve-controlled cylinderelectro-hydraulic position servo system low-frequency interference compensation method is easy to realize by computer numerical control.

In a fuel injection control system for an internal combustion engine provided with a low pressure fuel pump and a high pressure fuel pump, proportional plus integral control of a high pressure fuel pump is carried out to make a pressure of fuel come close to a target value between the high pressure fuel pump and fuel injection valves. In cases where the high pressure fuel pump is in operation, a feed pressure, which is a pressure of fuel between a low pressure fuel pump and the high pressure fuel pump, is caused to go down when an integral term in the proportional plus integral control does not change or is decreasing, and the feed pressure is caused to go up when the integral term is increasing. In cases where the high pressure fuel pump is in a stopped state, the feed pressure is made higher than before the high pressure fuel pump is stopped.

A method for controlling a dynamic response of a fuel control valve in a gas turbine fuel control system is provided. The method includes regulating a fuel supply pressure for a gas turbine using a component model, sensing a pressure of a fuel supply to the gas turbine, and applying a proportional plus integral control algorithm combined with a gas supply pressure feedforward signal to a pressure command signal controlling the fuel control valve to increase a system response in rejecting a pressure disturbance and increase a disturbance rejection bandwidth of a fuel control valve response.