To provide a controller for a rotary electric machine capable of suppressing occurrence of an angle interval when the rotary electric machine cannot output torque, even if the ON angle interval of the switching devices is set smaller than 120 degrees in the rectangular wave control. A controller for a rotary electric machine performs a rectangular wave control to a rotary electric machine which has 2 groups of three-phase windings, with a phase difference between groups; and switches a first control mode and a second control mode according to a switching condition; wherein the first control mode is a mode which sets an ON angle interval to an angle within a range from 120 degrees to 180 degrees; and wherein the second control mode is a mode which sets the ON angle interval to an angle within a range from 90 degrees to 120 degrees.

An apparatus for rectifying a resolver output signal may include: a resolver configured to receive an excitation signal and to output a resolver output signal based on the excitation signal, the excitation signal indicating a position of a rotor of a motor; a microprocessor configured to receive a reference rectification signal generated by rectification of the excitation signal and to output a delay signal by delaying the reference rectification signal according to a preset value; and a delay amount detection circuit configured to receive a reference excitation signal generated by rectification of the resolver output signal, to receive the delay signal from the microprocessor, to compare the reference excitation signal with the delay signal, and to output a phase difference detection signal and a delay amount excess/shortage signal to the microprocessor.

The present invention relates to a fan motor driving circuit, a driving method, and a cooling device and an electronic machine using the same. The present invention provides a motor driving circuit capable of suppressing strain on coil current and/or reducing noise. A control circuit a control circuit switches an output phase of an H-bridge circuit based on a Hall signal, and in a soft switching duration (Tss) that starts before and ends after the output-phase switching, slowly varies a duty ratio (DUTY1) of an output voltage (V.sub.OUT1) of one leg of the H-bridge circuit over time, and meanwhile, varies a duty ratio (DUTY2) of an output voltage (V.sub.OUT2) of another leg of the H-bridge circuit in an opposite direction with respect to the duty ratio (DUTY1) of the output voltage (V.sub.OUT1) of the one leg.

API duty calculation unit of a microcomputer that performs control at a predetermined control period calculates a duty ratio of a voltage applied to a coil of a motor from a target rotation speed and an actual rotation speed calculated by a number-of-rotation information unit. The PI duty calculation unit generates a rectangular wave signal having a period according to one frequency selected from plural predetermined frequencies together with the start of one control period and indicating the calculated duty ratio, and outputs the rectangular wave signal to a PWM duty calculation unit. The PWM duty calculation unit generates a PWM signal for controlling an inverter circuit based on the rectangular wave signal output by the PI duty calculation unit and position information of a rotor of the motor calculated by an electrical angle position information unit.

A method for checking an operation of an electric machine, which has three phases. For pulses of a first electric variable of the three phases, a pulse width modulation is carried out. Depending in each case on a positioning of electromechanical components of the electric machine with respect to one another, the first electric variable has a pulse with a longest pulse width for a first of the three phases, a pulse with an intermediate pulse width for a second of the three phases, and a pulse with a shortest pulse width for a third of the three phases. A cycle of the pulse width modulation is delimited by two points in time.

In a motor system, a switcher selectively switches a target motor, which is a target to be supplied with electric power output by a motor driver and a target to be detected for a current by a current sensor, among a plurality of motors. The switcher cyclically switches the target motor among the plurality of motors. When the current of the target motor is detected by the current sensor, the motor driver is controlled to output the electric power based on a PWM duty ratio computed based on the current, at a timing when the motor in which the current is detected is again the target motor, in a cycle after the cycle in which the current is detected.

A power tool, in particular a hand-held power tool, for example a polishing device, a grinding device and/or a sawing device, with a tool, an electric motor for driving the tool and a control unit for controlling the electric motor. The power tool is designed for connection to a mains voltage and includes a rectifier arrangement with an intermediate circuit for providing an intermediate circuit voltage based on the mains voltage, the Intermediate circuit voltage having a plurality of successive voltage half-waves, and the control unit being configured to provide, for each voltage half-wave, a respective torque half-wave for driving the electric motor, the waveform of which torque half-wave is flattened with respect to the waveform of the voltage half-wave.

A motor driver having a progressive driving mechanism is provided. The motor driver includes a progressive driving setting circuit, a progressive waveform constructing circuit and a motor driving circuit. The progressive driving setting circuit outputs a progressive driving setting signal that is progressively changed over time. The progressive driving setting signal has a plurality of progressive driving set voltages respectively at a plurality of set time points. The progressive driving set voltages are different from each other. The progressive waveform constructing circuit sets a plurality of waveforms of a progressive waveform signal according to the progressive driving set voltages. Duty cycles of the plurality of waveforms of the progressive waveform signal are different from each other. The motor driving circuit drives a motor according to the progressive waveform signal.

A motor driver circuit having a dynamic duty cycle modulation mechanism is provided. The motor driver circuit includes a magnetic field change sensing circuit, a control circuit, a driver circuit and an output stage circuit. The magnetic field change sensing circuit senses a plurality of voltages that are generated with a change in a magnetic field caused by a motor whose rotor is rotating to output a commutation signal. The control circuit sets a plurality of control duty cycles according to the commutation signal. The control circuit outputs a control duty cycle signal according to each of the control duty cycles. The driver circuit outputs a driving signal according to the control duty cycle signal. The output stage circuit operates to output a plurality of output stage signals to the motor according to the driving signal.