A method of controlling a DC motor that includes the step of providing a pulse-width modulation (PWM) signal to the DC motor. The PWM signal provides a voltage to operate the DC motor. The method also includes the steps of measuring a voltage generated by the DC motor when the PWM signal is off. In more particular embodiments, the method includes measuring a current being supplied to the DC motor when the PWM signal is off. The method may further require determining a motor speed of the DC motor based on the measured voltage. The method further includes controlling the DC motor to maintain a relatively constant motor speed with varying loads on the DC motor.

A method for fail-safe rotational speed monitoring of a sensorless three-phase drive, in which the three-phase drive is controlled in three phases with the phases U, V, W by drive electronics comprising an inverter, with the voltage signals at the three phases U, V, W being present as pulse width modulated signals, in which an output frequency of the inverter applied to the drive is determined and an actual rotational speed of the drive is determined therefrom, in which the actual rotational speed is compared with a predeterminable desired rotational speed and in which, if the actual rotational speed exceeds the desired rotational speed, the drive is switched off, the pulse width of the pulse width modulated signals being used to determine the output frequency of the inverter.

A compact motor control system for selectively controlling power from a power source to a load includes a motor switching assembly having a solid state contactor with a plurality of solid state switches. The motor switching assembly also includes at least one direct current (DC) link coupled to the solid state contactor and redundant first and second inverters coupled to the at least one DC link. The motor switching assembly further includes a first relay coupled between the solid state contactor and an input of the inverter and a second relay coupled between the solid state contactor and an input of the second inverter. In addition, the motor control system includes a control system programmed to control the motor switching assembly to selectively supply power to the load from the power source.

A method for fail-safe rotational speed monitoring of a sensorless three-phase drive, in which the three-phase drive is controlled in three phases with the phases U, V, W by drive electronics comprising an inverter, with the voltage signals at the three phases U, V, W being present as pulse width modulated signals, in which an output frequency of the inverter applied to the drive is determined and an actual rotational speed of the drive is determined therefrom, in which the actual rotational speed is compared with a predeterminable desired rotational speed and in which, if the actual rotational speed exceeds the desired rotational speed, the drive is switched off, the pulse width of the pulse width modulated signals being used to determine the output frequency of the inverter.

Disclosed are a Pulse Width Modulation (PWM) generation circuit, a processing circuit and a chip. The PWM generation circuit is used for controlling a rotation speed of an external motor system. The PWM generation circuit includes a second clock prescaler and a PWM signal generator. A frequency division output end of the second clock prescaler is connected to a data input end of the PWM signal generator. The PWM signal generator includes an output frequency divider and a comparator. A clock output end of the output frequency divider is connected to a comparison input end of the comparator. By means of the technical solution, PWM signals with different duty ratios.

A motor control system includes a motor; a motor and a motor control circuit coupled to the motor to provide power to the motor. The motor control circuit includes a power feedback loop having a power reference circuit to provide a reference power level and a power control circuit configured to provide a constant power level to the motor so that the motor operates with a substantially constant power output. The constant power level is proportional to the reference power level. Thus, the motor also provides substantially constant torque when the motor is at a constant speed.

Disclosed are a Pulse Width Modulation (PWM) generation circuit, a processing circuit and a chip. The PWM generation circuit is used for controlling a rotation speed of an external motor system. The PWM generation circuit includes a second clock prescaler and a PWM signal generator. A frequency division output end of the second clock prescaler is connected to a data input end of the PWM signal generator. The PWM signal generator includes an output frequency divider and a comparator. A clock output end of the output frequency divider is connected to a comparison input end of the comparator. By means of the technical solution, PWM signals with different duty ratios.

A method of controlling a DC motor that includes the step of providing a pulse-width modulation (PWM) signal to the DC motor. The PWM signal provides a voltage to operate the DC motor. The method also includes the steps of measuring a voltage generated by the DC motor when the PWM signal is off. In more particular embodiments, the method includes measuring a current being supplied to the DC motor when the PWM signal is off. The method may further require determining a motor speed of the DC motor based on the measured voltage. The method further includes controlling the DC motor to maintain a relatively constant motor speed with varying loads on the DC motor.

A data storage device is disclosed comprising a head actuated over a disk, and a spindle motor configured to rotate the disk. A pulse width modulated (PWM) control signal is generated having a frequency based on a PWM clock, the spindle motor is controlled using the PWM control signal, and a frequency of the PWM clock is swung between a minimum frequency and a maximum frequency at a swing rate.

A data storage device is disclosed comprising a head actuated over a disk, and a spindle motor configured to rotate the disk. A pulse width modulated (PWM) control signal is generated having a frequency based on a PWM clock, the spindle motor is controlled using the PWM control signal, and a frequency of the PWM clock is swung between a minimum frequency and a maximum frequency at a swing rate.