A drive control device for a motor includes an input terminal, an output terminal, an inverter circuit, a first switch unit, a capacitor, a diode, a rectifier circuit, a photo coupler, a second switch unit, and a voltage detector. The inverter circuit converts a direct current voltage into an alternating current voltage, and outputs the alternating current voltage to the output terminal. The first switch unit shorts the output terminal based on a control signal. The capacitor is connected to the input terminal, and is charged by a direct current voltage. The diode is connected between the input terminal and the capacitor. The diode limits a direction where a charge current for charging the capacitor flows. The rectifier circuit rectifies an induced voltage, which is generated in the motor, and outputs a rectified voltage. The photo coupler converts the rectified voltage into an optical signal, and thereafter, converts the optical signal into a converted signal. The second switch unit outputs the control signal based on the converted signal. The voltage detector detects whether the direct current voltage is input to the input terminal, and determines whether to negate the control signal.

A device for sensing a rotational position of a rotatable element for a household appliance includes: a stator having a plurality of capacitive sensor surfaces spaced apart from one another in a plane of extension of the stator; and a rotor rotatably positionable or disposed relative to the stator and having an electrically conductive section and a dielectric non-conductive section, the conductive section being larger in area than the non-conductive section, the rotor being disposed opposite the plane of extension of the stator in a rotatable condition relative to the stator, and the rotor being couplable or coupled to the rotatable element.

A magnetic pole detection circuit includes a multi-phase voltage divider unit, a filter unit, a DC level compensation unit, an amplifying unit, and a hysteresis comparison unit. The multi-phase voltage divider unit is configured to detect a back electromotive force (EMF) signal of a multi-phase motor. The filter unit is configured to filter the back EMF signal to generate a filtered signal. The DC level compensation unit is configured to compensate a DC level of the filtered signal to generate a compensation signal. The amplifying unit is configured to amplify the compensation signal to generate an amplified signal. The hysteresis comparison unit is configured to generate a zero-crossing point signal according to the amplified signal and a reference signal. The zero-crossing point signal is adapted to control an excitation mode of the multi-phase motor.

Described embodiments provide circuits, systems and methods for controlling operation of brushless direct current motors that include a plurality of windings. A gate driver provides control signals to switching elements that control a voltage applied to each of the windings of the motor. A zero crossing detector detects zero crossings of a voltage applied to the windings and transitions a zero crossing signal between a first logic level and a second logic level based on the detected zero crossings. A position estimator estimates an angular position of the motor, and counts in a first direction based on the first logic level of the zero crossing signal, and in a second direction based on the second logic level of the zero crossing signal. An observer determines a value of the counter after an elapsed time, and generates an angular position signal based upon the value of the counter.

A direct current electrical machine, which includes a rotor that generates a rotor magnetic field, a first commutation cell that includes a winding component, a first switching device, and a second switching device. The first winding component includes a first portion electrically coupled between a first terminal and a second terminal of the first winding component and a second portion electrically coupled between a third terminal and the second terminal of the first winding component. The first switching device is electrically coupled to the first terminal and is closed when a first voltage induced across the first portion by rotation of the rotor magnetic field is positive; and the second switching device is electrically coupled to the third terminal and is closed when a second voltage induced across the second portion by the rotation of the rotor magnetic field is negative.

An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.

A method includes measuring a speed of a motor, determining a phase angle of a motor voltage relative to a motor current based on the measured speed of the motor, adjusting a profile of the motor voltage by the determined phase angle, and generating a profile of a drive voltage based on the adjusted profile of the motor voltage and a back-EMF profile. An apparatus includes a motor, and a driver circuit. The driver circuit measures a speed of the motor, determines a phase angle of a motor voltage relative to a motor current based on the measured speed of the motor, adjusts a profile of the motor voltage by the determined phase angle, and generates a profile of a drive voltage based on the adjusted profile of the motor voltage and a back-EMF profile.

An electrical controller for electric rotating machines is provided. A control system for electric rotating machines transmits a controlled quantity of current to or from different windings of the electric rotating machine at any given time. Furthermore, the amplitude of the current is independently variable of the timing and duration of the transmission of the current to or from the windings. This allows increased control of the electric rotating machine and facilitates the operation of the electric motor at high mechanical and/or electrical speeds.

A battery state estimating apparatus as an embodiment includes a state estimator, a power estimator, and a determiner. The state estimator estimates a state of a battery. The power estimator estimates first power amount charged/discharged by the battery within a charging/discharging period, based on the state. The determiner compares the first power amount with second power amount inputted/outputted to/from the battery within the charging/discharging period and thereby determines validity of the state.

An electric working machine according to one aspect of the present disclosure comprises a brushless motor, a rotational position sensor, a detector, and a calculator. The calculator detects, when the brushless motor is inertially rotated, a difference between a detection result obtained by the rotational position sensor and a detection result obtained by the detector and calculates a correction value, based on the difference, for correcting the detection result obtained by the rotational position sensor.