An electric motor control device includes an electronic control unit configured to perform switching control of a switching element of an inverter in PWM control mode when a modulation degree is less than a first predetermined value, perform switching control of the switching element in square wave control mode when the modulation degree is greater than or equal to a second predetermined value, and perform switching control of the switching element in intermediate control mode when the modulation degree is greater than or equal to the first predetermined value and less than the second predetermined value. The intermediate control mode uses a switching pattern in which, in a pulse pattern in the square wave control mode, a slit or a short pulse having the same width as the slit is formed according to whether a pulse is present at the time when a phase current crosses zero.

An electric motor includes a rotor, and a stator. The rotor has a core, shaft rotatably supported on the core only on one axial side, and plurality of permanent magnets forming magnetic poles. In a case in which each of the magnetic poles is divided into rotation and reverse direction sides relative to a magnetic pole center, the rotor core has magnetic saturation promoting portion by which a half portion on the rotation direction side of at least one of the magnetic poles each including a corresponding one of the permanent magnets is likely to be magnetically saturated. The magnetic saturation promoting portion is provided in a more radially outward direction than the permanent magnet. Shapes of the half portions on the rotation and reverse direction sides are asymmetric about a first straight line passing through the pole center of the magnetic pole and an axial center of the rotor.

A device according to an embodiment includes an inverter main circuit; a detector configured to detect a current of an output line of the inverter main circuit; a starting time controller comprising a rotational phase angle estimator configured to calculate, based on a current response value detected by the detector, a value corresponding to a rotational phase angle of a motor connected to the inverter main circuit in a stationary reference frame, and a rotational speed estimator configured to calculate a value corresponding to a rotational speed of the motor by using the value corresponding to the rotational phase angle when the inverter main circuit is started; and a regular time controller configured to calculate, with the value corresponding to the rotational speed as an initial value, an estimated rotational phase angle of the motor in a rotating reference frame.

A control system for an electrical motor comprises a rotor, a stator having a plurality of phase windings, and an inverter for applying voltage to the plurality of phase windings by connecting individual phase windings to a first or second voltage level. The control system is configured to measure a first rate of change of current in a first phase winding, of said plurality of phase windings, connected to the first voltage level, to measure a second rate of change of current in a second, different phase winding connected to the first voltage level, and to calculate a difference between the first and second rate of change of current. The control system is further configured to use the calculated difference to obtain data related to a position of the rotor.

A power tool includes an output shaft, a motor, a housing, a detection unit, a storage device and a control unit. The output shaft is configured to output a torsion. The motor is configured to drive the output shaft to rotate. The housing is configured to accommodate the motor. The detection unit is configured to detect an operational parameter of the power tool. The storage device is configured to store at least a first threshold corresponding to a first operating condition set and a second threshold corresponding to a second operating condition set. The control unit is communicatively connected to the detection unit and the storage device.

A control unit calculates a motor voltage vector including a corresponding excitation voltage command and a torque voltage command in response to an output request for a motor and distributes the motor voltage vector to a first inverter voltage vector and a second inverter voltage vector while maintaining the motor voltage vector obtained to control modes of operation (PWM, overmodulation, and square wave mode) of a first inverter or a second inverter. The first inverter voltage vector includes an excitation voltage command and a torque voltage command associated with an output from the first inverter, and the second inverter voltage vector includes an excitation voltage command and a torque voltage command associated with an output from the second inverter.

An electric motor control device includes an electronic control unit configured to perform switching control of a switching element of an inverter in PWM control mode when a modulation degree is less than a first predetermined value, perform switching control of the switching element in square wave control mode when the modulation degree is greater than or equal to a second predetermined value, and perform switching control of the switching element in intermediate control mode when the modulation degree is greater than or equal to the first predetermined value and less than the second predetermined value. The intermediate control mode uses a switching pattern in which, in a pulse pattern in the square wave control mode, a slit or a short pulse having the same width as the slit is formed according to whether a pulse is present at the time when a phase current crosses zero.

A system for controlling a motor includes a controller module comprising a controller portion, a regulator portion and an integrator portion. The regulator portion includes a set of regulator modules communicatively coupled in a sequence. Each regulator module configured to receive a respective input signal, indicative of a target or selected value, from the controller portion or the immediately preceding regulator module in the sequence, determine a respective selectable value; select one of the respective selectable value and the value indicated by the received input signal; and provide the selected value as an output signal to the next regulator module in the sequence or the integrator module. The integrator module is configured to receive the output signal from the last regulator module in the sequence, calculate a final demand value based on the received signal, and provide an output signal indicative of the final demand value.

A motor drive device includes a power conversion circuit that drives an AC motor and a controller that controls the power conversion circuit. The controller includes a command current calculation unit generating a command current according to command torque for the AC motor and a current control unit that performs feedback control for adjusting a current applied to the AC motor to the command current. The controller also includes a control gain setting unit that calculates a control gain used for the feedback control based on the command torque and sets the calculated control gain in the current control unit. The control gain setting unit performs control such that a time from a decrease of an absolute value of the command torque to switching of the control gain is longer than a time from an increase of the absolute value of the command torque to switching of the control gain.

In an electric tool, a motor has a permanent magnet and a coil. An operating member receives an operating command. A control unit performs driving control on the motor in accordance with the operating command. A transmission mechanism transmits motive power of the motor to an output shaft. A switching mechanism switches an operation mode of the electric tool from a first mode to a second mode, or vice versa. Magnitude of variation in a rotational speed of the output shaft in response to a change by a unit quantity in an output torque of the output shaft is smaller in the first mode than in the second mode. The control unit can perform, in the first mode, flux weakening control that causes a flux weakening current to flow through the coil to make the coil generate a magnetic flux that weakens a magnetic flux of the permanent magnet.