The present invention addresses the problem of providing a method for detecting magnetic field location which can realize low cost by using simple hardware and software and can detect a rotor location in units of excitation sections in 120-energization without generating sensing noise at the time of initiation. As a solution, an MPU (51) obtains, through calculation, a neutral point potential from an energization-phase voltage measured by an A/D conversion circuit (53), obtains the difference between the neutral point potential and a non-energization-phase voltage, performs magnitude comparison between the difference and a negative-side threshold value in the case where the present location is an odd-numbered section or between the difference and a positive-side threshold value in the case where the present location is an even-numbered section, and determines the end point of the 60-energization section when the difference exceeds a threshold value in a direction away from the neutral point potential.

A motor control apparatus includes first and second detectors, and a switcher. The first detector detects a rotation position of a rotor using a signal from a resolver, and allows resolution of the rotation position to become lower in a region where a rotation speed of the rotor is higher than a first predetermined value, than in a region where the rotation speed is equal to or lower than the first predetermined value. The second detector estimates the rotation position using a current of the motor. The switcher switches between a first control and a second control in the region where the rotation speed is equal to or lower than the first predetermined value. The first control includes controlling the motor using the rotation position detected by the first detector. The second control includes controlling the motor using the rotation position estimated by the second detector.

A drive apparatus for a motor having a stator and a rotor, the drive apparatus including a current detection unit configured to detect, when the motor is rotating, each of multi-phase currents flowing through coils of the stator, and a control unit for controlling the motor by sensor-less control configured to convert the detected multi-phase currents into a d-axis current Id and a q-axis current Iq in a d-q coordinate system, calculate a phase error between an actual rotational position of the rotor and an imaginary rotational position thereof by comparing the d-axis current Id with a d-axis current command value Idref and comparing the q-axis current Iq with the d-axis current command value Idref, perform control so that the phase error gets closer to zero, and output voltage command values to a motor drive circuit.

A magnetic pole position detecting device for a synchronous motor includes: a storage unit for storing a reference magnetic pole position of the synchronous motor as a predetermined reference; a magnetic pole position detector for detecting the magnetic pole position of the synchronous motor when a predetermined condition is satisfied; and a determination unit for comparing the reference magnetic pole position stored in the storage unit with the magnetic pole position detected by the magnetic pole position detector to determine that detection of the magnetic pole position is abnormal when the difference between the two falls out of a predetermined range.

The present invention relates to a gear motor (101), in particular for a wiper system, comprising: a brushless DC electric motor (103) including: a rotor (15); a stator (13) having coils (17) for electromagnetically exciting the rotor (15); a device (25) for determining the angular position of the rotor (15) with respect to the stator (13); a control unit (21) configured to generate control signals for supplying power to the electromagnetic excitation coils (17) according to the angular position of the rotor (15) determined by the device (25) for determining the angular position of the rotor (15); a reduction gear mechanism (104) linked, on one side, to the rotor (15) of the electric motor (103) and, on the other side, to an output shaft (109) that is intended to be linked to an external mechanism, in particular a wiper system, the reduction gear mechanism (104) having a predefined reduction ratio, said device (25) for determining the angular position of the rotor (15) comprises at least one Hall effect sensor (27, 27a, 27b) associated with a control magnet (29, 29a, 29b) that rotates with the rotor (15) and the gear motor (101) also comprises a processing unit (26) connected to the device (25) for determining the angular position of the rotor (5) and configured to determine the angular position of the output shaft (109) on the basis of the angular position of the rotor (15) determined by taking the predefined reduction ratio of the reduction gear mechanism (104) into account.

An electric power steering apparatus including: a steering torque detector to detect a steering torque of a driver; a motor to assist a steering force of the driver; an estimated speed calculator to calculate an estimated speed, which is an estimated value of a rotation speed of the motor; an estimated speed corrector to correct the estimated speed based on the steering torque; an estimated angle calculator to calculate an estimated angle of the motor by integrating the estimated speed after the correction; and an electric power supply to supply electric power to the motor based on the estimated angle, wherein the estimated speed corrector corrects the estimated speed when a determination signal, which is based on a value obtained by removing a frequency component of steering of the driver from a derivative of the steering torque, the steering torque, and the estimated speed have the same signs.

According to the present invention, in position sensorless control for switching between a 120-degree energization scheme for a low-speed region and a 180-degree energization scheme for a mid-to-high-speed region, stable and highly accurate speed control characteristics are provided by suppressing speed deviation r in the low-speed region, and by preventing current jump-up caused by a discontinuous rotational speed occurring during switching to the mid-to-high-speed region. In the case of driving in the 120-degree energization scheme, a voltage command value is corrected such that an estimated speed value or a detected speed value follows a speed command.

A motor controller includes current measurement circuitry and estimation circuitry. The current measurement circuitry is adapted to be coupled to a motor, and configured to measure current in the motor. The estimation circuitry is coupled to the current measurement circuitry, and includes a memory, current computation circuitry, and summation circuitry. The memory stores coefficients of a function for estimating current related to variation of inductance of the motor. The current computation circuitry is coupled to the memory, and is configured to compute a compensation current value based on the coefficients. The summation circuitry is coupled to the current compensation circuitry, and is configured to generate a position error signal by subtracting the compensation current value from a measured current value generated by the current measurement circuitry.

An oil-pump motor drive apparatus includes a current detection unit for detecting each of multi-phase currents flowing through coils of a stator, a control unit for converting the detected multi-phase currents into a d-axis current Id and a q-axis current Iq, calculating a phase error between an actual rotational position of the rotor and an imaginary rotational position by comparing the d-axis current Id with a d-axis current command value Idref and comparing the q-axis current Iq with the d-axis current command value Idref, performing control so that the phase error gets closer to zero, and outputting voltage command values indicating voltages to be applied to respective phases of the brushless motor, to a motor drive circuit, in which the control unit sets the d-axis current command value Idref to a value larger than zero when the number of revolutions of the motor is smaller than a predetermined number.

A method of controlling a sensorless motor (32). The method contains the steps of determining a current speed of the motor (32); selectively using a first method, a second method, or a third method to determine a position of a rotor of the motor (32), depending on the current speed of the motor (32); and transmitting a drive signal to the motor (32) based on the determined position of the rotor. A sensorless motor assembly is also disclosed. According to the method, multiple rotor position detection methods are provided to the sensorless motor (32) which cover a full speed range of the motor (32).