Abstract: A power-assisted steering system includes a current detector for detecting sequentially current flowing to a ground-side switching element in a lower arm by a detection resistor inserted into the lower arm not only in a time period when the switching element is ON but also in time period when the switching element is OFF, an offset updating unit for sequentially updating an offset correction value with detected values in the time period when the switching element is OFF, and a detected current correcting unit for calculating a motor current value (a corrected current detected value) by correcting detected values in the time period when the switching element is ON with the offset correction value thereby updating.

Abstract: A resistor member having a resistance value substantially equal to a resistance of a relay in an ON state is inserted into a current supply path which is not inserted with the relay in current supply paths for supplying currents from a driving circuit to a brushless motor. Further, in the driving circuit, widths of bus bars forming wirings are set such that resistances of the wirings (contact resistance) from a branch point on power source side to Hi side FET (source terminals thereof) are equal to each other and widths of bus bars forming the wirings are set such that the resistances of the wirings from a ground side branch point NL to Lo side FET (source terminals thereof) become equal to each other.

Abstract: Current detecting circuits are provided for all phases of a motor driving circuit. A motor control portion is provided with a correction value calculating unit for calculating a correction value by dividing a total sum of motor current values based on detecting signals detected by the current detecting circuits of all the phases by a number of the phases of a motor and a motor current value correcting unit for correcting the motor current values by subtracting the correction value from the motor current values based on values of currents actually flowing in the respective phases of the motor. Thereby, the motor is driven.

Abstract: A power-assisted steering system includes a current detector for detecting sequentially current flowing to a ground-side switching element in a lower arm by a detection resistor inserted into the lower arm not only in a time period when the switching element is ON but also in time period when the switching element is OFF, an offset updating unit for sequentially updating an offset correction value with detected values in the time period when the switching element is OFF, and a detected current correcting unit for calculating a motor current value (a corrected current detected value) by correcting detected values in the time period when the switching element is ON with the offset correction value thereby updating.

Abstract: A first alternating signal of which phase changes according to changes in the rotation angle of a first shaft is output, and a second alternating signal of which phase changes according to changes in the rotation angle of a second shaft capable of rotating elastically with respect to the first shaft is output. A phase difference correspondence signal of which waveform changes according to changes in the phase difference between the first alternating signal and second alternating signal is output. A value corresponding to the torque transmitted by the first and second shafts is found from the phase difference correspondence signal.

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: Current detecting circuits are provided for all phases of a motor driving circuit. A motor control portion is provided with a correction value calculating unit for calculating a correction value by dividing a total sum of motor current values based on detecting signals detected by the current detecting circuits of all the phases by a number of the phases of a motor and a motor current value correcting unit for correcting the motor current values by subtracting the correction value from the motor current values based on values of currents actually flowing in the respective phases of the motor. Thereby, the motor is driven.

Abstract: A resistor member having a resistance value substantially equal to a resistance of a relay in an ON state is inserted into a current supply path which is not inserted with the relay in current supply paths for supplying currents from a driving circuit to a brushless motor. Further, in the driving circuit, widths of bus bars forming wirings are set such that resistances of the wirings (contact resistance) from a branch point on power source side to Hi side FET (source terminals thereof) are equal to each other and widths of bus bars forming the wirings are set such that the resistances of the wirings from a ground side branch point NL to Lo side FET (source terminals thereof) become equal to each other.

Abstract: The torque sensor outputs a sinusoidal first alternating signal the phase of which changes in accordance with change in the rotation angle of a first shaft, and a sinusoidal second alternating signal the phase of which changes in accordance with change in the rotation angle of a second shaft capable of performing relative rotation, elastically, with respect to the first shaft. 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 is output. A value corresponding to the torque transmitted by the first and second shafts is determined from the phase difference correspondence signal.

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: 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 torque sensor outputs a sinusoidal first alternating signal the phase of which changes in accordance with change in the rotation angle of a first shaft, and a sinusoidal second alternating signal the phase of which changes in accordance with change in the rotation angle of a second shaft capable of performing relative rotation, elastically, with respect to the first shaft. 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 is output. A value corresponding to the torque transmitted by the first and second shafts is determined from the phase difference correspondence signal.

Abstract: A first alternating signal of which phase changes according to changes in the rotation angle of a first shaft is output, and a second alternating signal of which phase changes according to changes in the rotation angle of a second shaft capable of rotating elastically with respect to the first shaft is output. A phase difference correspondence signal of which waveform changes according to changes in the phase difference between the first alternating signal and second alternating signal is output. A value corresponding to the torque transmitted by the first and second shafts is found from the phase difference correspondence signal.