2121results about "Current controllers" patented technology

Corresponding to a target torque, the control device calculates a target value of a feature based on at least one of the length of a long axis of a current vector locus and the length of the short axis and further superimposes a superimposed current on a drive current for the motor, the superimposed current having a frequency different from the frequency of the drive current. Further, the control device detects an actual value of the feature based on at least one of the length of a long axis of a current vector locus of the superimposed current and the length of the short axis of the same and finally detects a phase angle of the motor based on the target value and the actual value for the feature. The manipulation of a detecting phase is performed by feedback of a feature obtained by the magnitude of the superimposed current. That is, when the actual feature is more than the target value, the detecting phase is advanced. Conversely, when the actual feature is less than the target value, the detecting phase is delayed.

In an operation range of an actuator subjected to quick acceleration and deceleration, a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area. A controller comprises a voltage saturation detecting means for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

A motor driving apparatus includes an inverter circuit for converting an output voltage of a power supply into a three-phase AC and outputting the same to the brushless motor, a rotor position estimation unit for estimating a rotor position of the brushless motor, and an inverter control unit for controlling the inverter circuit so that the brushless motor is driven by a current based on the estimated rotor position. The inverter control unit determines an advance angle of the current supplied to the brushless motor with respect to the estimated rotor position so as to minimize a deviation between a command rpm and an actual rpm. Therefore, it is possible to perform stable weak field control for the brushless motor, independently from the input voltage of the inverter circuit, without using predetermined control variables such as table values.

A synchronous motor drive system in accordance with the present invention detects a DC current of an inverter which drives a synchronous motor, and based on the magnitude of the current, estimates torque current components that flow through the motor, and then based on the estimated value, determines the voltage which is applied to the motor, and finally estimates and computes the magnetic pole axis located inside the motor using the estimated value of the torque current.

Disclosed is a high-speed control method for a permanent magnet synchronous motor-compressor system, including the following steps: initial design is carried out; a motor is detected through DSP, including detecting the two-phase current of the stator of the motor, the voltage Udc of a DC generatrix; the voltage of a d-p shaft is calculated; faults of overcurrent, overpressure and undervoltage are detected; if any fault exists, the PWM pulse signals are blocked and then the control program is paused; if no fault exists, the following steps will be carried out; the rotating speed of the motor and the position of the rotor are identified in the process of speed-position estimation; the current and the voltage of the reference d-q shaft of the motor are calculated; switching signals of an inverter are acquired through haplotype over-modulation; the data are recorded and waveforms are displayed; judgment of whether to pause the control program is carried out; if not, the second step is carried out again; if yes, the control program will be paused. The control method applies haplotype over-modulation method into the permanent magnet synchronous motor-compressor system, realizing sensorless over-modulation to the synchronous motor-compressor vector control system.

When a short-circuit failure of any of switch portions (13) including switch elements (11) and parallel-connected feedback diodes (12) of an inverter circuit (7) is detected during the operation of a motor (1), a switch portion (13) where the short-circuit failure has occurred is checked for whether it is on the positive polarity side or the negative polarity side. The switch elements (11) are so controlled that all the switch portions (13) on the same polarity side as where the short-circuit has occurred are brought into a conducted state and all the others disconnected. This prevents a large electric current from flowing into each switch portion of the inverter circuit without requiring any switch to block the power distribution between a motor and the inverter circuit when a short-circuit failure of the switch portion of the inverter circuit occurs.

A rotating machinery includes a first control member for performing rectangular wave control by operating the switching devices of an inverter such that an on-state and an off-state occur once for one cycle period in electrical angle of a motor, a second control member for operating the switching devices on the basis of a magnitude relation between upper and lower limits of a predetermined hysteresis region and an actual current flowing through the motor, and a switching member for, when the actual current deviates from the hysteresis region while the rectangular wave control is undertaken, switching the control to an instantaneous current value control performed by the second control member.

Disclosed herein is a method for controlling an electric power steering system, wherein a motor is controlled by vector control and driven by a current command value calculated on the basis of a parameter such as a steering torque to provide a steering assist power to a vehicle steering system, and further wherein the current command value is limited on the basis of desired output characteristics and a desired angular speed during a field-weakening control and a non-field-weakening control of the vector control.

A control apparatus for a brushless DC motor that rotatably drives the brushless DC motor including a rotor having a permanent magnet, and a stator having stator windings of a plurality of phases that generate a rotating magnetic field for rotating the rotor, by a current passage switching device constituted by a plurality of switching elements and performing successive commutation of current to the stator windings. The control apparatus includes: an angular error calculation device for calculating a sine value and a cosine value of an angular difference between an estimated rotation angle with respect to the rotation angle of the rotor and an actual rotation angle, based on a line voltage that is a difference between phase voltages of the plurality of phases on an input side of the stator winding and phase currents of the plurality of phases; and an observer for calculating the rotation angle of the rotor based on the sine value and the cosine value of the angular difference.

A control unit of an electric power converter, which is used in a three-phase motor having two winding wire systems, performs for a first duty instruction signal regarding a voltage applied to a first winding wire group a flatbed two-phase modulation process, and performs for a second duty instruction signal regarding a voltage applied to a second winding wire group a flattop two-phase modulation process. By phase-shifting the second duty instruction signal by 30° from the first duty instruction signal, a timing of maximum value of the first duty instruction signal is shifted from a timing of minimum value of the second duty instruction signal. Even when the maximum value is greater than a center output value and the minimum value is smaller than the center output value, overlapping of capacitor discharge is avoided, thereby reducing a ripple electric current.

An electronically commutated motor comprises a rotor (208); a stator (201) electromagnetically interacting with the rotor (208), which stator is formed with a stator winding (202, 204, 206); a power stage (122) controlling the currents flowing in the stator winding (202, 204, 206) during operation; at least one current measuring element (242, 244) for sensing a measured value for the currents (I_UPPER, I_LOWER) flowing in the power stage, and an overcurrent measuring element (152, 162) for evaluating an associated measured value and for sensing a current whose absolute value exceeds a predetermined limit value (I_MAX_UPPER, I_MAX_LOWER); a holding element (154, 164) associated with the overcurrent measuring element (152, 162), configured, when an overcurrent occurs in the associated current measuring element (242, 244), to generate an overcurrent signal (OC_UPPER, OC_LOWER), to store the signal, and to deliver a signal to the power stage (122).

Provided are a motor controller for suppressing a torque pulsation with a simple configuration and obtaining a sufficient output torque in the case of an open-type fault occurring in any one of windings of a motor and inverters, and an electric power steering device using the motor controller. In the motor controller for controlling a current supplied from and a voltage applied from a power source with respect to the motor including winding sets of a plurality of systems, when a fault determination unit (31) determines the occurrence of the open-type fault, the supply of the currents to the windings of one of the systems in which the fault has occurred is stopped by control performed on switching elements included in the inverter of the faulty system, whereas the supply of the currents to the windings of the normal system in which the fault has not occurred is continued.

An inverter circuit for a motor outputs three-phase AC currents, which are outputted from common connection points to stator coils, based on output voltage of a DC power source and a power supply capacitor by a switching operation of transistors. An inverter control circuit determines that a system main relay is turned off, upon receiving a main relay-off signal from an electronic control unit. The inverter control circuit turns on the low-side transistors, while turning off the high-side transistors. A discharge current flows from the positive electrode to the negative electrode of the power supply capacitor through the stator coil and the low-side transistors, so that electric charge stored in the power supply capacitor is discharged.

There is provided a controller for a motor capable of changing the phase difference between two rotors that can prevent demagnetization of permanent magnets or the rotors. The motor has two rotors each having a permanent magnet and phase difference changing driving means for changing the phase difference between the rotors. The controller has a demagnetization determining means for determining whether or not demagnetization of the permanent magnets of the rotors occurs during operation of the motor, and rotor phase difference controlling means for controlling the phase difference changing driving means to change the phase difference between the rotors from a current phase difference to a phase difference that results in a higher strength of a composite field of the permanent magnets if the result of determination by the demagnetization determining means is positive.