Abstract: A power measurement device includes: a first three-phase to two-phase converter converting a three-phase voltage signal of three-phase AC power into a two-phase voltage signal; a second three-phase to two-phase converter converting a three-phase current signal of the three-phase AC power into a two-phase current signal; an instantaneous power calculator calculating an instantaneous value of active power of the three-phase AC power and an instantaneous value of reactive power of the three-phase AC power based on the two-phase voltage signal and the two-phase current signal; a first moving average calculator calculating multiple active power average values of different moving average data quantities; a second moving average calculator calculating multiple reactive power average values of different moving average data quantities; and calculators that calculate average active powers corresponding to a frequency of the three-phase AC power, and the reactive power corresponding to the frequency of the three-phase A

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average. A frequency calculator calculates an angular frequency based on the two-phase voltage signal, and an arithmetic unit calculates a system frequency of the power system from the angular frequency.

Abstract: A power measurement device includes: a first three-phase to two-phase converter converting a three-phase voltage signal of three-phase AC power into a two-phase voltage signal; a second three-phase to two-phase converter converting a three-phase current signal of the three-phase AC power into a two-phase current signal; an instantaneous power calculator calculating an instantaneous value of active power of the three-phase AC power and an instantaneous value of reactive power of the three-phase AC power based on the two-phase voltage signal and the two-phase current signal; a first moving average calculator calculating multiple active power average values of different moving average data quantities; a second moving average calculator calculating multiple reactive power average values of different moving average data quantities; and calculators that calculate average active powers corresponding to a frequency of the three-phase AC power, and the reactive power corresponding to the frequency of the three-phase A

Abstract: A system includes an orthogonal coordinate signal generator that generates an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency. A prediction calculator calculates a predicted value of the angular frequency after a time has elapsed based on the angular frequency and a differential of the angular frequency. In a state in which the phase jump of the power system is not detected, the frequency calculator calculates the system frequency based on the angular frequency. When the phase jump of the power system is detected, the frequency calculator calculates the system frequency based on predicted value for a constant amount of time.

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average. A frequency calculator calculates an angular frequency based on the two-phase voltage signal, and an arithmetic unit calculates a system frequency of the power system from the angular frequency.

Abstract: A process control system in a multi-input/output coordinate control system for executing coordinate control of a main input. The process control system sets an operating point set value for an operating point of an n-th control output, generates the n-th control output to control the main input based on the n-th control output, and generates an m-th control output to control the operating point of the n-th control output so that the operating point of the n-th control output becomes equal to the operating point set value, thereby to allow the n-th control output of fast response to operate at the operating point set value by controlling the main input.

Abstract: A process control system in a multi-input/output coordinate control system for executing coordinate control of a main input. The process control system includes operating point setting means for setting an operating point set value for an operating point of an n-th control output, n-th output control means for generating the n-th control output to control the main input based on the n-th control output, and m-th output control means for generating an m-th control output to control the operating point of the n-th control output so that the operating point of the n-th control output becomes equal to the operating point set value, thereby to allow the n-th control output of fast response to operate at the operating point set value by controlling the main input.

Abstract: An actuator controller using a periodic signal includes: an actuating unit for moving a movable portion with respect to a fixed portion by a predetermined amount; a drive unit for operation the movement; a power supply unit for supplying an electric power to the drive unit; and a periodic signal generating unit, which includes a velocity command signal generating part for generating a velocity command signal on the basis of an output of the movable portion, and a driving frequency calculating part for determining the frequency of the periodic signal in accordance with the velocity command signal.

Abstract: An adaptive controller for robots for driving an actuator of a robot arm under servo control where a servo constant is set such that the robot arm follows up a predetermined reference movement orbit. The controller has a switching section for switching between an adjustment mode where the servo constant is adjusted and a servo control mode where the servo constant is already set. Also included is a deviation supervising section for which obtains the deviation of an actual operation orbit of the robot arm from the reference movement orbit thereof, and operates the switching section to change the servo control mode into the servo adjustment mode when the obtained deviation exceeds a predetermined value. The controller also has a dynamic-characteristic-model identifying section for identifying the movement characteristic of the robot arm when the servo control mode is changed into the servo adjustment mode by the deviation supervising section and the switching section.

Abstract: A control system frequency response curve forming device for forming an comprising an original frequency response curve of an object to be controlled according to the dynamic characteristic data of the object; a model selector for selecting one of transfer function models which are low degree transfer functions prepared in advance to the original frequency response curve of the objects; an approximate curve moving device for moving an approximate curve corresponding to the selected model transfer function toward and away in order to fit the original frequency response curve and fixing a position of the approximate curve; a parameter deciding device for deciding parameters of the selected model transfer function according to the fixed position of the approximate curve; a selector for selecting one of control parameters deciding algorithms; and a control parameters deciding device for deciding the control parameters based on the selected model transfer function and according to the selected control deciding alg

Abstract: An adaptive process control system comprises a controller of an I-P type generating a manipulating variable signal with a feed forward circuit responsive to the set-point signal r(t), an integrator responsive to a difference between a process variable signal y(t) and set-point signal r(t), and a feedback circuit responsive to the process variable signal y(t). An identification signal generator superposes a persistantly exciting identification signal h(t) to the control system. A frequency characteristic identifying circuit receives a discrete controlled data u(k) and y(k), estimates the parameters of the ARMA model by the least square method to identify the pulse transfer function, and obtains the transfer function in the continuous system as the frequency characteristics of gain and phase. A controller parameter calculating circuit calculates the controller parameters of the controller, such as integration gain K, proportional gain f.sub.o, and feed forward gain f.sub.

Abstract: A process control apparatus comprises a main controller having a first integrator for integrating a difference signal between a set point and an output of a process and a PD (proportional-derivative) arithmetic operating unit for executing the PD arithmetic operation for the output of the process. The main controller obtains a control signal on the basis of an I-PD (integral-poroportional-derivative) control method and supplying this control signal to the process. A robust controller, connected to the output of the process, comprises a high-order differentiator for high-order differentiating the output of the process, a second integrator for integrating the difference signal between the set point and the output of the process, a subtractor for subtracting an output of the second integrator from an output of the high-order differentiator, and an amplifier for amplifying an output of the subtractor and feeding back this amplified output to the control signal.

Abstract: A process control apparatus has a controller for performing a control operation including an integral operation for a set point signal supplied to a process and an output signal from the process and for generating a control signal to the process, and a reference model which has a desired transfer function of a control system and which receives the set point signal. The process control apparatus further has a first subtractor for subtracting the output signal of the reference model from the output signal of the process, an output error compensator for performing a control operation including an integral operation for the output error and for generating a compensation signal in such a manner that the output error becomes zero, and a second subtractor for subtracting the compensation signal from the output control signal of the controller.

Abstract: The process control apparatus according to the present invention is adapted to control the process automatically in compliance with the state of the process characteristics. In the process control apparatus, when the process characteristics are found to be in a steady state, the control is performed by a first process control operational means suited for sample controlling the process according to the control constants for the first process control operational means as determined during the control of a second process control operational means, while, when the process characteristics vary frequently, the control is performed by the second process control operational means which is suited from sample controlling the process.

Abstract: A sampled-data I-PD control apparatus controls an interference multi-input/multi-output process in accordance with an I-PD action. The apparatus comprises an identification signal generator for superposing persistently exciting identification signals on control variables (inputs) of the process, an identifying circuit for identifying a pulse transfer function of the process in accordance with the control variables of the process and controlled variables (outputs) of the process, an S-transfer function calculator for transforming the identified pulse transfer function to an S-transfer function, and a tuning circuit for matching the S-transfer function with that of a process model and for tuning sampled-data I-PD control parameters in accordance with a matching result.

Abstract: A process control apparatus wherein dynamic characteristics of a process are identified in accordance with process inputs and outputs, so as to tune digital PID (Proportional-Integral-Derivative) parameters in accordance with the identified dynamic characteristics. The process is an N-input/output process having an interference between the process inputs and outputs. Each transfer function between a given process input and process output is identified. A transfer function between a set-point signal and the process output is obtained and matched with that of an N-input/output decoupled reference model, to tune the PID parameters.

Abstract: A digital PID process control apparatus is proposed wherein dynamic characteristics of the process are identified by supplying a persistently exciting signal to a closed-loop control system, and the persistently exciting signal is not supplied to the system after identification is completed, thereby tuning PID control parameters in accordance with the identified pulse transfer function. The control apparatus has a detector for detecting model error of the process in operation, a pulse generator for superposing a pulse signal on a set-point signal to the process when the model error is detected, a calculator for detecting a transient change in the model error when the input signal to the process changes in a pulse form, and a restart circuit for restarting generation of the persistently exciting signal when a change in the model error is detected, and for restarting an identification/tuning function.

Abstract: A process control apparatus is provided which has a PID controller to which is supplied a sampled signal of a control deviation signal of a process value signal and a reference signal and which generates a PID control signal according to sampled-value PID control constants. A non-linear controller is connected in parallel with the PID controller. A sum signal of the output signals from the PID controller and the non-linear controller is supplied to a process through a holding circuit. The process control apparatus further includes a circuit for identifying the dynamic characteristic of the process according to the sum signal and the sampled signal of the process value, and a circuit for calculating a transfer function of the process in the Laplace operator domain and for determining the sampled-value PID constants of the PID controller according to the dynamic characteristic.