Abstract: A motor controller judges whether or not a duty cycle of a PWM control signal, which is used to open and close a switching element on a power supply line to a motor, is in a current detection permission region. When the duty cycle is in the current detection permission region, an impedance is determined in time series via a calculation based on a predetermined relationship between a current, a terminal voltage, a speed electromotive force, and an impedance of a coil constituting an armature winding, and the output of the motor is controlled so as to reduce the deviation between a current target value and a value corresponding to a detected current. When the duty cycle is not in the current detection permission region, the output of the motor is controlled so as to reduce the deviation between the current target value and a value corresponding to a current determined via a calculation based on the latest determined impedance.

Abstract: An electric power steering system in which a current command for a brushless DC motor is determined based on a detected steering torque, a voltage to be applied is determined based on a difference between the current command value and a current value flowing to the motor, and steering assist is implemented by applying the voltage so determined to the motor. A rotational angular velocity is computed based on a detected rotor position, and it is determined that the motor is abnormal when a rotational angular velocity determination unit determines that the rotational angular velocity is equal to or less than a predetermined value, a current command value determination unit determines that the current command value is equal to or less than a predetermined value, and a voltage determination unit determines that the voltage applied to the motor falls out of a predetermined voltage range.

Abstract: A motor controller stores values corresponding to predetermined equivalent resistance which corresponds to power loss generated by switching on and off switching elements. Voltage command values are determined by adding voltage drop values determined from values corresponding to the equivalent resistance and values of current flowing in the switching elements to target applied voltage values corresponding to current command values which correspond to target output of a motor. The switching elements arranged in a power supply line to the motor are switched on and off by control signals generated according to the voltage command values.

Abstract: In a motor controller which supplies electric power to a motor of an electric power steering device from a main power supply and an auxiliary power supply, an N-channel MOS-FET is connected in parallel with a diode which is provided to prevent a sneak current from the auxiliary power supply to the main power supply. When electric power is supplied to the motor from the main power supply, the MOS-FET is turned on. Then, most of currents flow into the MOS-FET such that a power loss is reduced and a reduction in efficiency is prevented. The MOS-FET has high speed responsibility and excellent durability.

Abstract: An angle computing section determines an angle of a rotor, and an angular velocity computing section determines angular velocity of the rotor. A command current computing section determines, from a steering torque and vehicle velocity, command currents and taken along d-q axes. An open loop control section determines, from command currents and angular velocity, command voltages taken along the d-q axes in accordance with motor circuit equations. A d-q axis/three-phase conversion section converts the command voltages into command voltages of three phases. A ? computing section determines the number of armature winding flux linkages included in a motor circuit equation from a q-axis command voltage, the current value detected by a current sensor, and the angular velocity. Circuit resistance including armature winding resistance R included in the motor circuit equation may also be determined by means of the same configuration.

Abstract: The controller for a brushless motor controls motor current by executing updates of applied voltage to a coil in accordance with rotational position of a rotor, the target current, and the actual current flowing through the coil. The updates of applied voltage to the coil are executed according to the results of calculations of applied voltage to the coil in accordance with the rotational position of the rotor, the target current, and the actual current flowing through the coil, in order to generate power for rotating the rotor by varying magnetic field generated by the coil. The cycle time of the updates of applied voltage is shorter than the cycle time of the calculations of applied voltage corresponding to the rotational position of the rotor.

Abstract: A motor vehicle steering system includes a motor driving circuit connected between a power supply and a ground for driving a multi-phase motor, PWM signal generating unit for generating an each-phase PWM signal for controlling a current flowing through each of phases of the multi-phase motor and feeding the each-phase PWM signal to the motor driving circuit, a single current sensor connected between the motor driving circuit and the power supply or the ground, and each-phase current value computing unit for finding an each-phase current value flowing through each of the phases of the multi-phase motor on the basis of an output of the current sensor. The PWM signal generating unit shifts the fall or rise timing of a carrier wave of the each-phase PWM signal by a predetermined phase shift amount.

Abstract: An electric power steering apparatus which comprises: an angle detector for outputting a sine wave signal and a cosine wave signal corresponding to a rotor position of a brushless DC motor; and a torque detector for detecting a steering torque applied to a steering member, and which drives the brushless DC motor to assist steering based upon the sine wave signal and the cosine wave signal which were outputted from the angle detector and the steering torque detected by the torque detector. A sine wave signal and a cosine wave signal are squared and added to each other, and whether or not abnormality has occurred in the angle detector is detected by whether the addition result falls within a predetermined range. It is possible to detect abnormality in the angle detector at an early stage.

Abstract: A first restrict value calculating unit obtains a first restrict value Im1 on the basis of the integration value (Id2+Iq2) of a d-axis current detection value and a q-axis current detection value. A second restrict value calculator 50 calculates a second restrict value Im2 on the basis of the maximum value of the integration values of the squares IU2, Iv2, and Iw2 of 3-phase current detection values. A target current value It calculated by a target current calculating unit 21 is restricted by so that a current value limiter so as to be not greater than the first restrict value Im1 and the second restrict value Im2. By using the two restrict value restricting the motor driving current, it is possible to control properly the motor driving current in accordance with a general driving condition and various steering conditions.

Abstract: An electric power steering system is provided which is capable of providing a favorable steering feeling without using compensation logics such as of inertia compensation and friction compensation. The electric power steering system includes road-noise suppression control means (213) for controlling a steering assist motor (9) in a manner to damp torque transmission in a higher frequency region representing road noises than a frequency region representing road information. A friction value of a steering mechanism (A) is decreased enough to allow the intrinsic vibrations of the steering mechanism (A) to appear. Rotor inertia of the steering assist motor (9) is set to a value small enough to allow the frequencies of the intrinsic vibrations to be present in the frequency region where the torque transmission is damped by the road-noise suppression control means (213).

Abstract: A motor controller judges whether or not a duty cycle of a PWM control signal, which is used to open and close a switching element on a power supply line to a motor, is in a current detection permission region. When the duty cycle is in the current detection permission region, an impedance is determined in time series via a calculation based on a predetermined relationship between a current, a terminal voltage, a speed electromotive force, and an impedance of a coil constituting an armature winding, and the output of the motor is controlled so as to reduce the deviation between a current target value and a value corresponding to a detected current. When the duty cycle is not in the current detection permission region, the output of the motor is controlled so as to reduce the deviation between the current target value and a value corresponding to a current determined via a calculation based on the latest determined impedance.

Abstract: In a current control system for a cylindrical permanent magnet synchronous motor as the drive source of an electric power steering apparatus, proportional gain Kdp and integral gain Kdi of a d-axis current PI control portion 126 are respectively set to K1·Ld and K1·Rd on the basis of d-axis inductance Ld and d-axis resistance Rd of the motor. Further, proportional gain Kqp and integral gain Kqi of a q-axis current PI control portion 128 are respectively set to K2·Lq and K2·Rq on the basis of q-axis inductance Lq and q-axis resistance Rq of the motor (K1 and K2 are optional coefficients). In this case, both of the d-axis resistance Rd and the q-axis resistance Rq have values resulting from adding the external resistance R? including wiring resistance to the internal resistance R of the motor.

Abstract: A power-assisted steering system includes: two or more current detectors that detects current flowing to two or more phases of a motor and outputs detected current values; a correcting unit that corrects the detected current values output from the current detectors to compensate a difference in gain between the current detectors; and a motor driving driver that drives the motor based on a deviation between the target current value and corrected detected current values. When the same current flows to the phase in which the current flowing thereto is detected by the reference current detectors and the phase in which the current flowing is detected by the other current detector, the correcting unit calculates a gain correcting coefficient based on a detected current value of the reference current detector and a detected current value of the other current detector and corrects the detected current value of the other current detector.

Abstract: A motor vehicle steering system includes a motor driving circuit connected between a power supply and a ground for driving a multi-phase motor, PWM signal generating unit for generating an each-phase PWM signal for controlling a current flowing through each of phases of the multi-phase motor and feeding the each-phase PWM signal to the motor driving circuit, a single current sensor connected between the motor driving circuit and the power supply or the ground, and each-phase current value computing unit for finding an each-phase current value flowing through each of the phases of the multi-phase motor on the basis of an output of the current sensor. The PWM signal generating unit shifts the fall or rise timing of a carrier wave of the each-phase PWM signal by a predetermined phase shift amount.

Abstract: An electric power steering apparatus which comprises: an angle detector for outputting a sine wave signal and a cosine wave signal corresponding to a rotor position of a brushless DC motor; and a torque detector for detecting a steering torque applied to a steering member, and which drives the brushless DC motor to assist steering based upon the sine wave signal and the cosine wave signal which were outputted from the angle detector and the steering torque detected by the torque detector. A sine wave signal and a cosine wave signal are squared and added to each other, and whether or not abnormality has occurred in the angle detector is detected by whether the addition result falls within a predetermined range. It is possible to detect abnormality in the angle detector at an early stage.

Abstract: In a controller for an electric power steering apparatus, a target value calculation element, which calculates target values of the drive currents of a motor on the basis of a detected value of the steering torque, is constituted by a first integrated circuit provided in a chip. A drive signal value calculation element, which calculates drive signal values for driving the motor on the basis of the target values calculated by the target value calculation element, detected values of the drive currents of the motor, and a detected value of the rotary position of a rotor of the motor, is constituted by a second integrated circuit provided in another chip from the chip. A driving element drives the motor in accordance with the drive signal values. The first integrated circuit is connected communicably to the second integrated circuit. The calculation cycle of the drive signal values is set to be shorter than the calculation cycle of the target values.

Abstract: In a controller for brushless motor which suppresses the generation of abnormal noise when the motor current is controlled by updating voltages applied to the coils, the present values of the applied voltages to the coils are calculated from the d axis target current, the q axis target current, the d axis actual current, the q axis actual current, and the present value of the detected rotational position of the rotor. The updating period of the applied voltages is set as a period that is shorter than this calculation period. The predicted value of the rotational position at a point in time at which the applied voltages are updated until the next calculation of the present values of the applied voltages is determined in accordance with the present value, a past value of the detected rotational position, and the applied voltage updating period.

Abstract: In a controller for brushless motor which suppresses the generation of abnormal noise when the motor current is controlled by updating voltages applied to the coils, the present values of the applied voltages to the coils are calculated from the d axis target current, the q axis target current, the d axis actual current, the q axis actual current, and the present value of the detected rotational position of the rotor. The updating period of the applied voltages is set as a period that is shorter than this calculation period. The predicted value of the rotational position at a point in time at which the applied voltages are updated until the next calculation of the present values of the applied voltages is determined in accordance with the present value, a past value of the detected rotational position, and the applied voltage updating period.

Abstract: The torque sensor outputs a signal from a first detector which corresponds to the rotation angle of a first shaft, as a first alternating signal the phase of which changes in accordance with this change in the rotation angle, via a resistance and a capacitor which function as a low-pass filter and a high-pass filter. A signal is output from a second detector corresponding to the change in the rotation angle of a second shaft capable of performing relative rotation, elastically, with respect to the first shaft, as a second alternating signal, the phase of which changes in accordance with the change in the rotation angle, via a resistance and a capacitor which function as a low-pass filter and high-pass filter. A value corresponding to the torque transmitted by the first and second shafts is determined from a phase difference correspondence signal the waveform of which changes in accordance with change in the phase difference between the first alternating signal and the second alternating signal.

Abstract: The controller for a brushless motor controls motor current by executing updates of applied voltage to a coil in accordance with rotational position of a rotor, the target current, and the actual current flowing through the coil. The updates of applied voltage to the coil are executed according to the results of calculations of applied voltage to the coil in accordance with the rotational position of the rotor, the target current, and the actual current flowing through the coil, in order to generate power for rotating the rotor by varying magnetic field generated by the coil. The cycle time of the updates of applied voltage is shorter than the cycle time of the calculations of applied voltage corresponding to the rotational position of the rotor.