Abstract: A motor system with reduced common-mode noise includes an AC power, a first transformer unit electrically connected to the AC power and providing a first DC power, and a second transformer unit electrically connected to the AC power and providing a second DC power. The first DC power is supplied to a motor driving section of the motor system, and the second DC power is supplied to a motor controlling section of the motor system. Therefore, a common-mode noise from the transformer winding for the motor driving section can be prevented from coupling to the transformer winding for the motor controlling section. Moreover, a safe stop signal is applied to turn down a PWM IC for power through a photo coupler or a relay. Therefore, the first transformer unit stops supplying current to the motor driving section of the motor system to enhance safe stop function for the motor system.

Abstract: A back electromotive detection comparator compares back electromotive voltages Vu to Vw with a common voltage Vn of coils, and generates first rectangular wave signals Pu to Pw. A masking circuit performs masking of the first rectangular wave signals Pu to Pw, and outputs the resultant signals as second rectangular wave signals Mu to Mw. An output circuit supplies a drive current to coils on the basis of the second rectangular wave signals Mu to Mw. A frequency generating circuit generates a frequency generation signal SigFG whose level switches at every edge of the second rectangular wave signals Mu to Mw. A mask signal generating circuit generates a mask signal MSK which is at a high level during an interval multiplied by a coefficient to a pulse width Tp of the frequency generation signal SigFG after level transition of the frequency generation signal SigFG.

Abstract: A method is proposed for supplying electrical power to a DC motor (16) which can be commutated electronically via a semiconductor power output stage (28), preferably a three-phase DC motor, through which a control unit (22) passes current in blocks, corresponding to the signals from a rotor position sensor (20). Current is passed through the motor (16) variably in steps, in such a manner that the magnitude and/or the duration and/or the trigger angle of the current blocks can be varied as a function of the rotation speed and/or of the load, with respect to the profile of the induced voltage (E).

Abstract: Motor start circuit for an induction motor, particularly a single-phase AC induction motor, with a main winding (4) and an auxiliary winding (5), which are supplied with current, particularly alternating current, via current supply connections (24, 25), and with a start switching device (15) serving the purpose of interrupting the current flow through the auxiliary winding (5) after the start of the motor, the start switching device (15) being connected to a control device (20) via a connector (18), the control device (20) being connected between the current supply connections (24, 25), and with a winding protection switch (28), which is normally closed and which opens on the occurrence of a fault. The invention is characterized in that the control device (20) is connected to the winding protection switch (28) via at least one further connector (22, 17), preferably via at least one further connector (22, 17) and the auxiliary winding (5).

Abstract: A system for controlling a trapezoidally (square wave) driven DC motor includes a unipolar commutation circuit coupled between a DC power supply and a brushless DC motor. The motor has three phases formed by respective stator windings coupled at respective proximal ends to a common node and having respective opposite ends remote from the common node. The commutation circuit drives the motor according to a commutation cycle including three primary steps. During each primary step, one of the phases is driven while the other two phases are not driven. Voltages at the remote ends of the undriven phases are sensed, and timing signals are generated at points where the voltages coincide. The timing signals are used to determine motor position and speed, and to synchronize the commutation cycle with motor position and speed. In one embodiment, the commutation cycle includes transitional steps between the primary steps for smoother operation.

Abstract: A motor driving device includes an amplifying unit, a noise removing unit, an analog-to-digital converter, a calculating unit, and a motor driving unit. The amplifying unit amplifies an analog frequency signal corresponding to a rotation speed of a direct-current brushless motor. The noise removing unit removes noise from the analog frequency signal after amplification. The analog-to-digital converter converts the analog frequency signal from which noise is removed to a digital frequency signal. The calculating unit calculates a current control amount with respect to each phase of the direct-current brushless motor based on the digital frequency signal. The motor driving unit drives the direct-current brushless motor at a specified speed based on the current control amount.

Abstract: A brushless DC motor drive circuit includes a drive unit and a transient current suppression circuit. The drive unit comprises a Hall component, a drive component, a first transistor and a second transistor. The Hall component detects the position of a rotor of the DC motor and transmits digital command signals to the drive component; the drive component further generates two complementary digital command signals; and the first and second transistors connect with the drive component respectively. The transient current suppression circuit comprises a first auxiliary transistor and a second auxiliary transistor, wherein the first auxiliary transistor receives one of the complementary digital command signals different from the other one received by the first transistor and the second auxiliary transistor receives the other one of the complementary digital command signals different from the one received by the second transistor.

Abstract: An RFI/EMI filter for a variable frequency motor drive system includes a variable frequency drive; a common mode choke; a motor; a cable including a plurality of power leads interconnecting the motor with the variable frequency drive and passing through the choke; a ground shield surrounding the cable and connected to motor ground and variable frequency drive ground; and a common mode return conductor interconnected between the variable frequency drive and the motor and disposed within the shield and passing through the choke for returning a portion of the common mode current to cancel a portion of the saturation current experienced by the choke to increase the portion of the common mode current carried by the return conductor and decrease the portion carried by the shield to reduce the RFI/EMI contributed by the shield.

Abstract: A brushless motor system which can suppress adverse influences of electromagnetic noise without increasing the size and enhancing the performance of a filter circuit. In a brushless motor system comprising a brushless motor, an inverter, and a direct current power source, a noise return line for returning a noise current is connected between the brushless motor and the inverter. The noise current is generated in the inverter and reaches the brushless motor. With the provision of the noise return line, a common mode current leaking from the brushless motor to a ground can be reduced.

Abstract: A ripple detecting device for detecting a ripple from an armature current outputted from a motor by overlapping a low band noise having a frequency of one/n (wherein “n” is a natural number more than 1) includes an initial ripple detecting device for detecting a cycle of the ripple in advance, a feature detecting device for detecting a feature of the ripple from the armature current outputted from the motor. The ripple detecting device further includes a ripple detecting control device for detecting the ripple by comparing the feature of the ripple with the low band noise having the frequency of one/n detected by the feature detecting device at a time before the present time with the feature of the ripple detected by the feature detecting device at the present time and judging that a ripple is generated when the features of the time before the present time and the present time present are resembled.

Abstract: A device for moving a movable structural component with respect to a stationary structural component includes a first fastening element which can be fastened to the movable structural component, and a housing tube having a second fastening element which can be fastened to the stationary structural component. A spindle drive for moving the first fastening element axially relative to the housing between an extended position and a retracted position includes a spindle nut arranged on a threaded spindle. An electric motor arranged in the housing tube drives one of the spindle nut and the threaded spindle in rotation. A power supply for supplying power to the electric motor includes a power output stage arranged in the housing tube, wherein the power output stage is shielded from electrical and magnetic fields.

Abstract: There are provided an electric power converter in which common-mode noise is suppressed without causing enlargement of components, increase in the number of components, a cost hike, and the like. The electric power converter is provided with a capacitor (12) connected with the input terminal of the inverter circuit (13a), a noise suppression means (10a, 10b) that is provided around at least one of input-side conductors connected with the input terminals of the inverter circuit (13a) and output-side conductors connected with the output terminals of the inverter circuit (13a), an electric quantity detector (11, 19a, 19b, 19c) that is provided in the input-side conductors or the output-side conductors at a position opposite to the inverter circuit with respect to the noise suppression means (10a, 10b), and a control unit (20) that controls the inverter circuit (13b), based on an electric quantity detection signal from the electric quantity detector.

Abstract: A load drive apparatus includes a noise filter, which includes a coil connected in series between a power source and a load, and a switching transistor connected in parallel across the coil, and a control circuit which is operated based on a drive signal. The control circuit turns on the switching transistor of the noise filter in case of subjecting the load to a full-on drive, thereby to short-circuit the coil and to form a power supply path including the switching transistor without the coil. The control circuit turns off the switching transistor of the noise filter in case of subjecting the load to a PWM drive, thereby to form a power supply path including the coil.

Abstract: The invention relates to an electronically commutated motor (10) and to a method of controlling an electronically commutated motor (10). In order to reduce commutation noise, it is proposed to influence the working range of the power-stage transistors (20, 22) with the aid of a component (48), in such a way that each transistors produces, during energization of each respective stator winding, a substantially constant current through the stator winding (12, 14). Preferably, each power-stage transistor operates within a pinch-off range.

Abstract: A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60° is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30°, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30°??? and 30°+?? are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Abstract: An inverter system comprises a PWM generator that generates a control signal that causes a switching device to output an output value, a carrier signal generator that outputs a carrier signal to the PWM generator, a carrier frequency changing unit that changes a frequency of the carrier signal, and a target frequency setting unit that sets a target frequency and calculates a specific frequency from the target frequency. The carrier frequency changing unit changes a carrier frequency so that the specific frequency matches with a harmonic component of each of values of the carrier frequency.

Abstract: The present invention discloses a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof. The brushless dc motor driver circuit of the present invention comprises a Time-Voltage Digital/Analog Converter. The Time-Voltage Digital/Analog Converter further comprises: at least one magnetic field detecting circuit, at least one counter, and a signal processor. The Time-Voltage Digital/Analog Converter is connected to a driver circuit of a brushless dc motor and detects the periodically varying magnetic field of the brushless dc motor. Based on the rising time and the falling time of the preceding magnetic field variation, the Time-Voltage Digital/Analog Converter calculates the elapsed time from the current phase-change point and generates a linearly rising signal and a linearly falling signal. Then, those two sets of analog signals are used to drive the brushless dc motor. Thereby, the vibration or shock noise of the brushless dc motor is reduced.

Abstract: Disk drive spindle jitter is comprised of electrical noise, error due to pair pole asymmetry, and random disk speed variances. Error caused by pair pole asymmetry can be identified and compensated for by detecting over a single rotation of a rotor a plurality of zero cross signals. These signals can be statistically analyzed over a period of a plurality of revolutions of the rotor so as to identify the systematic error caused by pair poles. Once identified, this pair pole error can be used to modify zero cross signals and/or modify commutation signal driving the disk so as to arrive at a more accurate determination of disk speed and to precisely control the speed of the disk.

Abstract: An RFI/EMI filter for a variable frequency motor drive system includes a variable frequency drive; a common mode choke; a motor; a cable including a plurality of power leads interconnecting the motor with the variable frequency drive and passing through the choke; a ground shield surrounding the cable and connected to motor ground and variable frequency drive ground; and a common mode return conductor interconnected between the variable frequency drive and the motor and disposed within the shield and passing through the choke for returning a portion of the common mode current to cancel a portion of the saturation current experienced by the choke to increase the portion of the common mode current carried by the return conductor and decrease the portion carried by the shield to reduce the RFI/EMI contributed by the shield.