Abstract: In order to enable in a motor system, in which a soft start of the motor has been implemented, the operation of the motor, wherein the power consumption is reduced, it is proposed to operate the driver circuit during a switch-on phase in order to carry out a soft start of the motor. In at least one embodiment, the driver circuit can be bypassed in a normal operational phase as a function of a load, by means of which the motor is operated.

Abstract: An electric switch, in particular for an electric tool with an electric motor. The switch has first electrical terminals for electrical connection to a voltage supply and second electrical terminals for electrical connection to the electric motor. The switch has an actuating mechanism which can be adjusted between an initial position and a final position, wherein the electric motor is switched off when the actuating mechanism is located in the initial position and is switched on when the actuating mechanism is not located in the initial position. The switch also has a braking circuit for braking the electric motor, the braking circuit operating when the actuating mechanism is reset to the initial position. The switch also has a reversal circuit for switching over the direction of rotation of the electric motor. The braking circuit is arranged between the second electrical terminals and the reversal circuit.

Abstract: The invention relates to a method for decelerating a drive movement of a power tool and to a power tool suitable for carrying out the method, having a drive driven by a motor, an energy supply device for the provision of electrical energy, a controller having a motor controller for activating the motor and an operating-state recognition module which is to detect at least one operating-state variable and, as a function of this, to output a brake signal, the controller being designed to initiate, as a function of the brake signal, a braking procedure in which brake cycles are provided which have a first time segment, in which the motor is short-circuited, and a second time segment in which current is fed to the motor opposite to its original direction of rotation.

Abstract: The invention relates to a yarn-tensioning device for producing a specific thread pull on a thread (5) that is unwound from a winding point (7) of a creel (2) and is guided to a warping machine arrangement (1). Said yarn-tensioning device comprises a rotating body (18) which is at least partially wound round by threads and an electric motor (19) which is connected to the rotation body. Said motor (19) is equipped with at least one brake transistor (20) for discharging excess energy produced when the generator of the motor is operated, said brake transistor being able to convert generator energy, arising when the generator is operated, into heat.

Abstract: Systems and methods are provided for regenerative motor braking. The regenerative braking systems and methods allow the braking torque of a multi-phase motor to be controlled while keeping currents to acceptable levels and without supplying electrical energy back to the voltage source. The regenerative braking systems and methods dissipate energy in the motor windings instead of sending this energy to the voltage source by intelligently switching the low-side switches in the inverter between the ON and OFF states at the commutation frequency while maintaining the high-side switches in the inverter in the OFF state.

Abstract: The invention relates to a traction drive for the driving and generative braking of a rail vehicle or a combination of rail vehicles, at least one permanent-field synchronous motor and a traction current converter being associated with at least one axle of the rail vehicle or combination of rail vehicles. The traction current converter includes at least one pulse current converter on the engine side, and the clamps of the permanent-field synchronous motor are connected to a change-over switch such that the permanent-field synchronous motor can be connected to a load circuit forming a load, to drive the pulse current converter or for generative braking. According to the invention, the load circuit connected to the permanent-field synchronous motor for generative braking is designed and/or controlled in such a way that the characteristic values of the load circuit can be modified according to the loading of the rail vehicle or combination of rail vehicles.

Abstract: A motor control circuit for controlling a motor includes a brake circuit and a control circuit. The brake circuit is for making the motor enter a braking state. The control circuit is for detecting a residual energy of the motor in the braking state. When the residual energy conforms to a predetermined criterion, the control circuit makes the motor exit the braking state.

Abstract: The present invention advantageously provides methods for manually and/or remotely controlling a motorized roller shade that includes a shade attached to a shade tube, a DC gear motor disposed within the shade tube and a microcontroller. One method includes detecting a manual movement of the shade using a sensor, determining a displacement associated with the manual movement, and, if the displacement is less than a maximum displacement, moving the shade to a different position by energizing the DC gear motor to rotate the shade tube. Another method includes receiving a command from a remote control, and moving the shade to a position associated with the command by energizing the DC gear motor to rotate the shade tube.

Abstract: A fan system including a motor with a coil, a storage unit, a driver, and a buffer circuit is provided. The coil module has a first connection terminal and a second connection terminal. The storage unit electrically couples with a voltage source, stores electrical energy when the voltage source is available, and releases the stored electrical energy to carry out a brake operation when the voltage source is unavailable. The driver electrically couples with the first and second connection terminals of the coil module to control a direction of an inductor current passing through the coil module. The buffer circuit electrically couples with the coil module. In the brake operation, the buffer circuit operates to form a transient potential between the first and second connection terminals of the coil module and to consume electrical energy of the inductor current, for gradually stopping the motor in a buffering time period.

Abstract: A driving device for a hatch in a vehicle, with a housing tube connected to a base part or to a movable structural component part, a protective tube connected to the movable structural component part or to the base part, a spindle drive having a threaded spindle and a spindle nut arranged on the threaded spindle by which the housing tube and the protective tube are movable axially relative to one another. A rotary drive drives the spindle drive in rotation includes at least one electric motor. The driving device has a safety circuit that causes a braking effect on the rotary drive when the rotary drive is deactivated and when extraneous forces are introduced into the driving device from the outside.

Abstract: A dynamic braking circuit for an electronic motor drive shunts the DC link of the drive with a resistor using two control strategies. The first control strategy used for lower levels of braking employs a pulse width modulated signal and the second control strategy used for higher levels of braking uses a hysteretic signal significantly reducing switching losses in the semiconductor devices controlling the dynamic braking resistor allowing higher braking capacity.

Abstract: The following invention is an electromechanical system (1) that is to be connected to an electricity supply (7), comprising: an electric machine (2) that can operate as an independent generator with a rotating shaft, and a switching system (9) allowing i) in the first configuration, the electric machine to operate as a motor in the case where the connected device (4) is normally driven or as a generator in the case where the coupled device is normally driving, and ii) in the second configuration, the electric machine to operate as an independent generator, the electrical energy generated by the electric machine (2; 22) being dissipated in the machine and in a dissipative load (13).

Abstract: A motor driving circuit comprising: a synchronous rectification driving circuit to carry out synchronous rectification, to energize a driving coil connected between a first connection point at which a first source and first sink side transistors are connected in series and a second connection point at which a second source and second sink side transistors are connected in series; a backflow detecting resistor connected to electrodes of the first and second sink side transistors, the electrodes being on an opposite side of the first and second sink side transistors to the first and second connection points; a backflow detecting comparator to output a comparison signal indicating a result of comparison of voltage between a first and second terminals of the backflow detecting resistor; and a backflow prevention circuit to prohibit the synchronous rectification when the comparison signal indicates that the second terminal is higher in voltage than the first terminal.

Abstract: To reduce noise by limiting a current peak value to a predetermined value or less and by smoothing the waveforms of drive currents during the current limitation, switching control means (30) according to the present invention turns ON all of one-side drive transistors selected from the high-side drive transistors (21, 22 and 23) and the low-side drive transistors (25, 26 and 27) of power supply means (20) for a predetermined period, and turns OFF all of the other-side drive transistors for a predetermined period in response to a current control signal for the current peak value to a predetermined value or less.

Abstract: The present invention provides a positioning device for positioning a table, including a base, a motor that drives the table in the driving area on the base, a position sensor that detects the position of the table, and a control unit that controls the motor. The control unit includes a first output unit that outputs electric current for controlling the position of the table based on the output of the position sensor; a second output unit that outputs electric current for imparting a thrust force, which is directed toward the center of the driving area, to the table; and a switch unit that switches from a state in which the motor is controlled depending on the output of the first output unit to a state in which the motor is controlled depending on the output of the second output unit, based on a stopping signal for stopping the table.

Abstract: A drive system for a multi-phase electric machine with a permanent magnet rotor, the drive system may comprise conduction paths for each phase. Detectors on each of the conduction paths may determine electrical condition of the conduction path. At least one selectable interconnection path may be present between all of the conduction paths. The at least one selectable interconnection path may be operable to connect all of the conduction paths together responsively to one or more of the detectors determining that the electrical condition of its respective electrical path is representative of a predetermined electrical fault condition so that heating of the rotor during continued rotation of the rotor is prevented.

Abstract: The invention relates to a method and an arrangement for braking a synchronous motor (4) used with a frequency converter (2). The braking current of the motor (4) is controlled by connecting only the negative changeover contacts (10) of the inverter (16) of the frequency converter (2) or alternatively by connecting only the positive changeover contacts (17) of the inverter (16) of the frequency converter. The arrangement comprises a control (3), which is arranged to control in a braking situation only the negative changeover contacts (10) of the frequency converter (2) or alternatively only the positive changeover contacts (17) of the frequency converter (2).

Abstract: One aspect according to the present invention includes a power tool including a control device that can output a brake operation signal to a DC motor to apply a short-circuit brake thereto in response to turning off an operation switch. The brake operation signal is stopped depending on the rotational speed of the motor when the operation switch is turned off during the rotation of the DC motor.

Abstract: An apparatus for controlling a wheel motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the wheel motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the wheel motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.

Abstract: In a motor control circuit which controls energization of a coil on the basis of a detection result of a rotor position, control is performed so that continuous rotation of the rotor by inertia is suppressed, rotation is stopped quickly, and reverse rotation of the rotor is prevented. When an external control signal CTL is changed from L to H, the normal rotation control is switched to reverse rotation control, and a reverse brake state is effected. When motor rotation speed is monitored and reduced to a set rotation speed, a brake control signal SPSB is changed from L to H, and a short brake state is effected. However, the motor continues to be rotated by its own inertia, and a position detection signal HALL is changed. Thus, reverse brake control is temporarily performed (only during a time period corresponding to a pulse width TRB). The short pulse reverse brake control is intermittently performed until the motor is completely stopped.

Abstract: A drive circuit having asymmetrical drivers. In an embodiment, a brushless DC motor may be driven by a drive circuit having three high-side MOSFETs and three low-side MOSFETs. A driver controller turns the MOSFETs on and off according to a drive algorithm such that phase currents are injected into motor coils to be driven. The high-side MOSFETs may be sized differently than the low-side MOSFETs. As such, when a MacDonald waveform (or similar drive algorithm) is used to drive the phases of the motor, less power may be required during disk spin-up because the MOSFETs that are on more (e.g., the low-side MOSFETs with a MacDonald waveform) may be sized larger than the MOSFETs that are on less (e.g., the high-side MOSFETs). In this manner, less power is dissipated in the larger size MOSFETs that are on more than the others.

Abstract: In order to reduce the time and expense of designing and operating a motor control system with multiple motors of different types, a motor control system is provided with motor control modules that monitor and record status information and update settings in a uniform manner regardless of the motor type under control. Each motor control module includes an output power stage and a motor control unit connected to each other. The status information includes status information about the output power stage or a current control loop connected to the output power stage. The settings include conditions monitored by each motor control module and corresponding actions taken by each motor control module based on the conditions. A host processor connected to the multiple motor control modules may request the common status information and send messages to update common settings of the motor control modules.

Abstract: A fan system includes a stator magnetic pole, a driving unit and a real-time stopping unit. The driving unit is coupled with the stator magnetic pole and controls a polarity change of the stator magnetic pole in accordance with a driving signal. The real-time stopping unit is electrically connected with the driving unit. When the fan system is powered off, the driving unit enables two ends of the stator magnetic pole to have the same voltage level in accordance with a control signal generated by the real-time stopping unit so that the fan system stops operating immediately.

Abstract: An electronic system for controlling a fan motor includes a microcontroller and a drive circuit. The microcontroller draws power from a first voltage source and generates control signals for sending drive current to stator coils of a fan motor via the drive circuit. The electronic system further includes a second voltage source to provide the microcontroller with an amount of energy sufficient to operate for a short period of time when the voltage of the first voltage source drops below a predetermined level. The microcontroller is configured to detect when the voltage level of the first voltage source drops below a given level and generates control signals for the drive circuit to discharge energy in the stator coils of the fan motor to quickly stop operation of the fan motor within a short period of time.

Abstract: A container, adapted to be opened/closed automatically by induction actuated, includes a container body, cover, motor and actuating device, wherein the motor is connected to the driven element of the cover through the actuating device. The dustbin includes a sensing and controlling device of the stroke of the cover, wherein a cover stroke perception and a shut off circuit, the cover stroke perception is connected with the shut off circuit, and the shut off circuit is connected with the motor, the shut off circuit receives the activating signal from the cover stroke perception and then controls the motor to actuate correspondingly, the cover's stroke inducted by the trigger; point of the cover stroke perception is less than the whole stroke during the closing of the cover. The noise of the crash between the cover and the container body is low, and closing of the cover is rapid and spiffy.

Abstract: An electric motor has a DC link circuit (30, 32), a permanent-magnet rotor (104), and a control circuit having a full bridge (114). A program-controlled calculation arrangement (80) is configured to supply the semiconductor switches of a first bridge half with a PWM signal (136, 136?) and to supply the semiconductor switches (118, 122) of the second bridge half with a commutation signal (O1, O2; 150, 150?). An energy storage device (170) is provided which, during normal operation of the motor (102), is chargeable from the DC link circuit (30, 32) and serves, upon cessation of the signals from the calculation arrangement (80), to make the semiconductor switches (118, 122) of the other bridge half conductive, and thereby to short-circuit the stator winding arrangement (106) through those semiconductor switches (118, 122) in order to decelerate the permanent-magnet rotor (104) and to thereby minimize risk of human injury.

Abstract: A method of dynamic motor braking is disclosed herein. The method comprises: dissipating reverse energy in a motor within motor windings during a non-current supplying period of a commutation sequence by intermittently shorting the motor windings. The motor windings are shorted by simultaneously turning on all switches that are connected to a voltage source or to ground in a three-phase bridge motor control.

Abstract: A fire or smoke barrier 1 has a curtain 2 deployed from a motorised roller 3 mounted in a head box 4. Remote from the head box and connected to the motor via a cable 5 is a motor controller circuit 6. A short circuit protection circuit 9 is connected to the motor within the roller at the motor end of the cable 5. On the motor side of the circuit 9 is a retarder circuit 10 connected across the motor terminals. The short circuit circuit comprises a pair of relays 11, 12, arranged with their normally open contacts 111,121 arranged in parallel. A drive voltage one 11 of the relays has its winding 112 across the input lines 14 of the circuit and the emf one 12 of the relays has its winding 122 across the output lines 15 of the circuit. The input lines 14 are connected to the cable lines 51,52 and the output lines 15 are connected to the motor terminals 16, via the retarder 10.

Abstract: To provide a rotary tool driven by a brushless motor with which constant torque tightening work for screws or the like can always be performed properly and efficiently, in which overall downsizing and improved torque control precision enhancement can easily be achieved, and with which it is possible to eliminate occurrences of switch contact-induced sparking and wear and of the damage imparted to the peripheral electronic equipment and electronic circuitry as occurred in drive switches or torque detection mechanisms that use a conventional mechanical switch mechanism, so that the constituting parts are able to have a reduced size and an extended life.

Abstract: An electric motor for a textile machine can be operated as a generator if the supply voltage fails. The electric motor comprises a rotor configured as the motor armature and a motor phase control circuit comprising a plurality of semiconductor components wherein the electric motor can be short-circuited if a predeterminable limit value is passed during generator operation. The motor circuit causes the short-circuiting on passing the limit value by activating one or more of the semiconductor components. The multi-phase electric motor is used as the single drive of a rotor of the textile machine. wherein the semiconductor components of the phase control bridge. on passing a predeterminable limit value, contactlessly short-circuit the electric motor to brake the electric motor.

Abstract: The invention relates to a device for damping the movement of a movable element (1) relative to a fixed element (3). The device comprises means for generating an electric current changing with the speed of movement of the movable element (1) relative to a fixed element (3). According to the invention, the device also comprises means (20 to 25) for modifying the mechanical properties of a fluid situated between the movable element (1) and the fixed element (3) by means of the electric current. The means (4 to 7, 8, 10) for generating an electric current comprise a generator comprising a rotor (4 to 7) and a stator (8, 10), the rotor (4 to 7) being fixedly attached to the movable element (1) and the stator (8, 10) being fixedly attached to the fixed element (3). Advantageously a magnetorheological fluid, bathed in a magnetic field generated by the electric current, is used.

Abstract: The invention relates to a method and an arrangement for braking a synchronous motor (4) used with a frequency converter (2). The braking current of the motor (4) is controlled by connecting only the negative changeover contacts (10) of the inverter (16) of the frequency converter (2) or alternatively by connecting only the positive changeover contacts (17) of the inverter (16) of the frequency converter. The arrangement comprises a control (3), which is arranged to control in a braking situation only the negative changeover contacts (10) of the frequency converter (2) or alternatively only the positive changeover contacts (17) of the frequency converter (2).

Abstract: When a wind velocity sensor detects a wind velocity higher than a predetermined level, a timer device starts a waiting timer function during an operation timer period shorter than the waiting timer period. After the waiting timer period is over, the waiting timer function is switched to an operation timer function, and a switching relay switches a generator to a motor only during an operation timer period. Then, a driving circuit performs a start assisting rotation. After the operation timer period is over, the waiting timer period re-starts. This process is repeated. When during this period, the number of rotations of a rotor monitored by a rotation number measuring device, based on the output voltage Vm of a three-phase conduction coil exceeds a predetermined number of rotations, the charging of a battery by a three-phase generator is started.

Abstract: A drive signal generation circuit generates drive signals that control ON and OFF states of transistors of a H-bridge circuit, in accordance with a target value of torque. A driver circuit alternatively turns ON and OFF high side transistors, and low side transistors of the H-bridge circuit, based on the drive signals outputted from the drive signal generation circuit. The driver circuit immediately turns OFF the high side transistors, when an instruction is issued to stop a motor, and after a predetermined delay time ?d has elapsed, turns OFF the low side transistors.

Abstract: Provided is a drive regenerative control system of a drivee with a motor superior in torque and weight balance and suitable for miniaturization as the drive source. In a drive regenerative control system having a drive source with an electric motor, a drivee, a control circuit having a drive control circuit of the motor and a regenerative control circuit, and a detection unit for detecting the driving status of the drivee, the drive control circuit and regenerative control circuit have a control unit for controlling, linearly or in multiple stages, the duty ratio of the drive or regenerative signal to be supplied to the motor based on the phase difference of the phase of the detection signal from the detection unit and the command value signal to the motor.

Abstract: During PWM control in which an actuator (9) is connected between the output terminals of a bridge circuit made up of switching elements (121, 122, 221, 222) and power is applied to the actuator (9) with signals G1U, G1L, G2U and G2L, driving timing signals are generated with a time interval (dead time) during which the switching elements (121, 122) and the switching elements (221, 222) are simultaneously turned off, and the actuator (9) is driven so as to have no overlapping dead time between a pair of half-bridge circuits, achieving response even with a differential input PWM signal (S51-S52) having a small time difference.

Abstract: Method and system of monitoring operations of an electric motor. The method and system being applicable to any number of motors of the type used to drive moveable members, including but not limited to motors used to drive automatic vehicle windows and motors used to drive automatic vehicle seats.

Abstract: Provided is a drive regenerative control system of a drivee with a motor superior in torque and weight balance and suitable for miniaturization as the drive source. In a drive regenerative control system having a drive source with an electric motor, a drivee, a control circuit having a drive control circuit of the motor and a regenerative control circuit, and a detection unit for detecting the driving status of the drivee, the drive control circuit and regenerative control circuit have a control unit for controlling, linearly or in multiple stages, the duty ratio of the drive or regenerative signal to be supplied to the motor based on the phase difference of the phase of the detection signal from the detection unit and the command value signal to the motor.

Abstract: A motor control apparatus that drives and controls a holeless DC motor is disclosed. The motor control apparatus includes a breaking part configured to break the DC holeless motor, a detection part configured to detect whether the DC holeless motor is in a near halt rotation state, and a forced stopping part configured to forcibly stop rotation of the DC holeless motor when the detection part detects that the DC holeless motor is in the near halt rotation state.

Abstract: The invention relates to a direct current motor control circuit. The invention also relates to the use thereof in a windscreen wiper system for vehicles. An MOS FET transistor with an anti-parallel diode (M3) is serially mounted on the braking system (M2) of the control circuit.

Abstract: A motor power supply including a DC supply part having a pair of supply terminals; an inverter having a pair of connection terminals respectively connected to the supply terminals thereof to receive DC power therefrom and to supply AC power to a motor, a breaking resistor and a control switching element disposed in parallel in an additional line connecting the pair of connection terminals to each other, a control switching element disposed with the breaking resistor in the additional line, a breaking switch disposed to one of the connection terminals and switched to either a normal position or a breaking position connecting the one connection terminal to a corresponding supply part or to the additional line, a speed detector detecting a motor speed and a control part controlling the breaking switch to switch to the breaking position and controlling the control switching element so that an on-off interval of the control switching element is controllable depending on the detected speed.

Abstract: A braking chopper for dissipating braking power away from the direct-current rails of an AC drive system, said braking chopper being an inverter unit (INU) physically similar to those also used as motor supply devices, consisting of upper- and lower-branch controllable semiconductor switches (V1–V6), wherein the inverter is connected by its output connectors to the direct-current rails (DC) via a resistor unit, which resistor unit contains two resistors (R1, R2), of which the first is connected to the positive direct-current rail (DC+) and the second to the negative direct-current rail (DC?), wherein both lower-branch and upper-branch semiconductor switches are turned on during braking, and wherein one brake resistor is controlled by the lower-branch switch of only one phase and the second brake resistor by the upper-branch switch of another phase.

Abstract: A braking device for an electric motor of a power tool has a short circuit switch for short circuiting an armature winding of the electric motor during a braking process, the short circuit switch for controlling its switch condition having a control input, a control unit connected with the control input of the short circuit switch for performing a phase control of the short circuit switching during the braking process in order to avoid brush fire; also an electrical device with such a braking device and a braking method are proposed as well.

Abstract: A method of dynamically damping an electric motor (12) that is controlled by an H-bridge driver (16) by interdigitating power pulses with braking pulses by switching from a power switch mode to a shorting circuit mode with switches (22 and 26) closed that brakes the electric motor.

Abstract: An electric machine selectively operates as a generator mode or a motor mode. The electric machine includes a stator core, a multi-phase armature winding, a field coil, a moving core having a plurality of salient poles so as to move relative to the stator core to cross the magnetic field. Field current is supplied to the field coil differently according to operation mode. A portion of the armature winding is short-circuited to form an additional magnetic field that has a phase different from the magnetic field of the field coil. Therefore, the rotary core moves relative to the stator core when the operation mode is in the motor mode.

Abstract: A braking device for an electric motor of a power tool has a short circuit switch for short circuiting an armature winding of the electric motor during a braking process, the short circuit switch for controlling its switch condition having a control input, a control unit connected with the control input of the short circuit switch for performing a phase control of the short circuit switching during the braking process in order to avoid brush fire; also an electrical device with such a braking device and a braking method are proposed as well.

Abstract: In an intelligent electric motor, the rotating speed and performance of a conventional electric motor is changed based on a means controlled by a computer, and the means is installed in the housing of the intelligent electric motor. For example, in the intelligent AC motor, the three-phase power is connected to the three-phase stator winding by three groups of control gates. All of the gates are switched on or off by a signal from the control means. When each of the three groups of control gates is switched on sequentially, the three-phase power is connected to the three-phase stator winding of the three-phase intelligent electric motor at the speed &dgr; in turn, so that the speed of the rotating magnetic field of the intelligent electric motor n0 is increased by a sped &dgr;. Therefore, the actual speed of the motor, n′0, is equal to n0±&dgr;, so the speed and performance of the motor is changed.

Abstract: The combining of two technically contrasting functions of “safe stopping” and “braking by armature short-circuiting” is served by using two means for pulse inhibition to block the respective current valves in the event of a fault by interrupting respective supply voltages for driving the control valves of the upper bridge arm and those of the lower bridge arm. For the purpose of braking by armature short-circuiting, the stator winding of a three-phase AC motor is short circuited in the event of a fault, or else operationally, by virtue of the fact that all current valves of a bridge arm can be switched on, a voltage being provided for switching on these current valves via a logic unit when the respective supply voltage for driving the current valves of this bridge arm are interrupted by the means for pulse inhibition.

Abstract: A discrete Kalman filter 12 and a disturbance estimating unit 13 are added to a feedback loop for feeding back a detected value of position from a position detector 6. The Kalman filter estimates position and velocity of an object to be controlled, thereafter outputting an estimated value of position and an estimated value of velocity. The disturbance estimating unit estimates from a command value of current and the estimated value of velocity the disturbance that is added to a load 5. The estimated value of position is fed back to a position controller 1, and the estimated value of velocity is fed back to a velocity controller 2. Further, a difference between a target value of current outputted from the velocity controller and the estimated value of disturbance is output as the command value of current.

Abstract: A method is disclosed for controlling the voltage applied to a voice coil motor coil during the retract operations of a mass storage device, comprising a combination of three different voltage regulator stages. This method includes providing a first circuitry stage adapted to source current to a voice coil motor apparatus, raising the voltage across the voice coil motor to a desired level, providing a second circuitry stage adapted to draw current from the voice coil motor effecting a desired voltage across the voice coil motor, and providing a third circuitry stage adapted to raise the voltage of the voice coil motor to ground by effectively shorting the voice coil motor to ground.