Abstract: A boat comprises a hull, a primary steering mechanism carried by the hull, a control station located on the hull, a helm located at the control station, and a thruster system carried by the hull. The primary steering mechanism, such as a rudder, is operable via the helm with a helm input being derived from operation of the primary steering mechanism thereby. The thruster system includes at least one thruster mounted to the hull, distinct from the primary steering mechanism, and a controller. The controller receives the helm input and is configured with program instructions to operate the at least one thruster responsive to the helm input to supplement a corresponding movement of the hull. The controller can also automatically operate the thruster responsive to direction, speed and ballast inputs.

Abstract: A method for controlling a marine propulsion device having an engine rotatably engaged with a transmission via a clutch, and rotatably engaged with a charging device for charging a battery. The method includes measuring a voltage of the battery and comparing the voltage to a minimum threshold. The method further includes increasing a speed of the engine when the voltage is below the minimum threshold, and also increasing a slip of the clutch when the speed of the engine is increased in response to the voltage being below the minimum threshold.

Abstract: An electric work machine (2) includes a motor (M) and a control unit (36) that controls rotation of the motor. The control unit (36) is configured such that an operating mode is switchable between a normal mode, in which the motor is rotated within a prescribed output range, and a power mode, in which the motor is rotatable with energy greater than in the normal mode. Furthermore, the control unit (36) is configured to restrict use of the power mode.

Abstract: A dynamic energy harvesting and variable harvesting force system is disclosed. A boost converter increases a motor voltage as a motor current associated with the motor voltage propagates through the boost converter thereby generating a boost voltage associated with the changing motor current. A power storage device stores energy harvested by the boost converter when the boost voltage exceeds an energy storage threshold. A controller dynamically adjusts a harvesting force applied by the motor so that the harvesting force is relative to the force applied to the motor. The controller also dynamically adjusts the harvested energy stored by the power storage device by adjusting the charging of the power storage device, ensuring that the boost voltage threshold is maintained. The boost voltage when maintained within the boost voltage threshold enables the power storage device to store the harvested energy without impacting the harvesting force applied by the motor.

Abstract: A method for controlling an output of an LDC in an environmentally friendly vehicle is provided. The method includes determining whether the vehicle travels in the regenerative braking mode and when the vehicle does, transmitting a first slope signal to the LDC to increase an output voltage of the LDC that charges or discharges an auxiliary battery supplying power to an electric load using a high voltage battery. The first slope signal determines an upward slope of the output voltage of the LDC according to time as a first slope. When the vehicle does not travel in the regenerative braking mode and uses a high power electric load a second slope signal is transmitted to the LDC to increase the output voltage of the LDC. The second slope signal determines the upward slope as the second slope having a slope less than the first slope.

Abstract: A propulsion system includes an electric drive, a first energy storage system electrically coupled to the electric drive through a DC link, and a second energy storage system electrically coupled to the first energy storage system in a series connection. The first energy storage system comprises a high specific-energy storage device and the second energy storage system comprises a low specific-power storage device. The propulsion system also includes a third energy storage system comprising a high specific-energy storage device electrically coupled to the second energy storage system. A bi-directional boost converter is electrically coupled to the second and third energy storage systems such that a terminal of the third energy storage system is electrically coupled to a low voltage side of the bi-directional boost converter and a terminal of the second energy storage system is coupled to a high voltage side of the bi-directional boost converter.

Abstract: A method and apparatus for setting a maximum depth of discharge of an energy reservoir for a time period. The method includes: defining a first target aging value of the energy reservoir for a first time period; determining a first aging value that describes an aging of the energy reservoir during the first period; calculating a first difference between the first target aging value of the energy reservoir and the first aging value of the energy reservoir; defining a second target aging value of the energy reservoir for a second time period; calculating a maximum aging value of the energy reservoir for the second time period, based on the second target aging value and at least the first difference; calculating a maximum depth-of-discharge value based on the maximum aging value; setting the maximum depth of discharge of the energy reservoir for the second time period to the maximum depth-of-discharge value.

Abstract: An apparatus comprising a battery unit and an electronics unit. The battery unit has a battery with a first and a second pole. The battery unit has at least a first, at least a second and at least a third electrical contact, wherein the first contact and the third contact are connected with the first pole, and wherein the second contact is connected with the second pole. The electronics unit has an input circuit with at least a first and at least a second electrical countercontact for receiving electrical energy from the battery unit essentially via the first and second contacts or essentially via the second and third contacts of the battery unit.

Abstract: A low pass filter circuit (100) structure is provided. The low pass filter circuit structure includes first and second dominant inductor (114, 116)s, a first capacitor (120) and first and second shunt capacitors (122, 124). The first dominant inductor has a first end and a second end and the second dominant inductor has a first end and a second end. The second end of the first dominant inductor is electrically connected to the second end of the second dominant inductor. The first capacitor is electrically coupled between the first end of the first dominant inductor and the first end of the second dominant inductor. The first shunt capacitor is electrically coupled between the first end of the first dominant inductor and a ground potential, and the second shunt capacitor is electrically coupled between the first end of the second dominant inductor and the group potential.

Abstract: A method of power tuning an electric system, the electric system including an electric machine and a control system for driving the electric machine in response to control values stored in a power map. The method includes loading the control system with a first power map, driving the electric machine with the control system, measuring a power of the electric system, and loading the control system with a second power map in the event that the measured power lies outside a predetermined range.

Abstract: A battery power system, adapted for driving a motor system of a power unit with respect to at least one power mode signal and at least one motor control signal generated from the motor system, which comprises: a battery pack, an electrolytic capacitor, a boost converter, a first contactor, a first switch, an ultracapacitor, a first diode, a second contactor, a second switch, a current limiting element, a plurality of measuring elements, and an electrical energy controller; wherein the electrical energy controller is enabled to analyze the electrical power level of the ultracapacitor according the power mode signal, the motor control signal and the voltage/current signals generated from the plural measuring elements while using the result of the analysis to control the current directions and conductivity of the boost converter, the first contactor, the second contactor, the first switch and the second switch so as to achieve a variety of control modes accordingly.

Abstract: A motor driving system with a pair of units connected in series to form a DC power supply with an intermediate potential connection point, positive and negative electrode lines connected to the positive and negative sides of the power supply through positive and negative electrode side switching circuits, an intermediate potential line with one end connected to the intermediate potential point, a DC to DC converter unit having two switching devices connected in series between the positive and negative electrode lines, a DC link circuit connected in parallel to the DC to DC converter unit between the positive and negative electrode lines, and a DC to AC converter unit driving an AC motor, the other end of the intermediate potential line connected to the connection point between the switching devices with a reactor in the intermediate potential line or in each of the positive and negative electrode lines.

Abstract: A method for controlling a vehicle drive unit, which comprises at least two individual drives, at least one of which is able to provide a negative torque. A vehicle control unit is provided, within which a continuous torque comparison is performed within a monitoring level. A permissible torque is ascertained therein. Using a torque range checker it is established whether ascertained setpoint torques lie within torque ranges of the at least two individual drives.

Abstract: A system includes a power source, a compressor that operates in a reduced-capacity mode and a full-capacity mode, and an actuation assembly that modulates the compressor between the reduced-capacity mode and the full-capacity mode. A controller reduces the power source to a predetermined level prior to the power source being supplied to the actuation assembly for use by the actuation assembly in controlling the compressor between the reduced-capacity mode and the full-capacity mode.

Abstract: Systems and methods for providing electrical power and to downhole oil production equipment such as electrical submersible pumps, wherein the outputs of multiple power modules are individually filtered before being added together to obtain a high voltage output that is provided to the downhole equipment. In one embodiment, an electrical drive system includes multiple power modules and corresponding filters. Each of the power modules is configured to receive an input power signal and to provide a corresponding pulse width modulated or stepped intermediate signal. The signal output by each power module is individually filtered to remove at least a portion of high-frequency components in the signal. The power modules and filters are coupled together in a configuration in which the filtered signals of the power modules are added to produce an output drive signal that is used to drive equipment such as an electrical submersible pump.

Abstract: A controller of a field winding type synchronous motor is provided that can stably output torque even if the d-axis current pulsates by reducing torque pulsation without causing fluctuation in the magnetic flux acting on the torque. A motor control unit 100 performs control so that a desired torque can be generated from a field winding type motor 20 having a field winding 22f on the rotor. Based on a current Id flowing in the d-axis direction out of the current flowing in a stator winding 22a of the field winding type motor 20, the motor control unit 100 calculates an induced voltage Vf2 being induced in the field winding 22f and compensates a field voltage Vf of the field winding based on the induced voltage Vf2, thus suppressing pulsation of the field current flowing in the field winding of the field winding type motor 20.

Abstract: A motor driver comprises a first power supply, a second power supply, a multiplexer, and an output power module. The first power supply provides a first power signal after a first period. The second power supply provides a second power signal after a second period, where the second period is longer than the first period. The multiplexer initially selects the first power signal and then selects the second power signal. An output power module controls a motor and receives power from an output of the multiplexer.

Abstract: An electric power system comprises an AC motor, a first DC voltage unit, an inverter as a power converter, being connected between the AC motor and first DC voltage unit, for exchanging power between these two components; and a controlled DC power supply which is connected between an arbitrary spot of a coil of the AC motor and a positive or negative electrode of the first DC voltage unit and which connects at least one semiconductor switching element and a battery as a second DC voltage unit in series.

Abstract: A power supply system is provided with a plurality of driving motors, a power converter, and a plurality of power supplies which supply the driving motors with power and have different output voltages. Each power supply is connected with at least one driving motor through the power converter and with at least one driving motor through a path which does not include the power converter.

Abstract: A motor control apparatus comprises a control processing unit (3) creating a motor drive command, power supply processing units (2A to 2D) supplying a driving voltage to a motor, and a signal relay processing unit (4) supplying the motor drive command received from unit (3) to power supply processing units (2A to 2D). Control processing unit (3) transmits a preparation request flag to power supply processing units (2A to 2D) via signal relay processing unit (4), which includes a preparation complete flag register storing preparation complete flags each transmitted from each of power supply processing units (2A to 2D) to indicate the completion of preparation for supplying power to the motor, and transmits a preparation complete flag enabled state to control processing unit (3) if contents of the preparation complete flag register indicate that the preparation is completed in all units (2A to 2D).

Abstract: A motor driver comprises a first power supply, a second power supply, a multiplexer, and an output power module. The first power supply provides a first power signal after a first period. The second power supply provides a second power signal after a second period, where the second period is longer than the first period. The multiplexer initially selects the first power signal and then selects the second power signal. An output power module controls a motor and receives power from an output of the multiplexer.

Abstract: Switching device for linking various electrical voltage levels in a motor vehicle, in which a drive voltage level has an electric drive machine which may be actuated by a power converter, and a drive energy accumulator which is associated with an intermediate circuit, and in which the drive voltage level is connected to a vehicle electrical system voltage level by an electrical converter. The electrical converter is designed as a coupling circuit which is connected at the drive side to at least one node point of a winding circuit of the electric drive machine and to a voltage potential relative to the intermediate circuit. The coupling circuit is connected at the vehicle electrical system side to the vehicle electrical system via a switching unit which has at least one non-diminishing, finite impedance.

Abstract: A step motor driving circuit is provided. An exemplary step motor driving circuit includes an input voltage source set, a reference voltage source, a voltage level shift unit, a logic unit, a reset voltage source, and an output voltage terminal. The input voltage source set provides an input voltage set. The reference voltage source provides a reference voltage. The voltage level shift unit raises one of the levels of the input voltage set to a level of the reference voltage. The logic unit receives the reference voltage and the input voltage set and outputs a control voltage. The reset voltage source outputs a reset voltage to reset the logic unit. The output voltage terminal receives the control voltage and outputs an output voltage.

Abstract: A safety circuit for providing protection against failures that impact safety of an inverter circuit driving a Permanent Magnet Synchronous Motor (PMSM) including high and low side switches connected in a bridge and driven by a gate driver circuit during operation of the PMSM in a field weakening mode, the gate driver circuit including stages for driving the high and low side switches, the safety circuit comprising a main power supply and a back-up power supply for supplying voltage to the gate driver circuit driving the switches of the bridge of the inverter circuit, wherein if the main power supply fails to deliver adequate power to the gate driver circuit, the back-up power supply provides power to the gate driver circuit to allow the gate driver circuit to turn ON the low side switches and turn OFF the high side switches.

Abstract: An apparatus for producing tractive effort, the apparatus comprising: an energy source adapted for generating a high DC voltage; a motor drive adapted for generating a motor voltage from the high DC voltage; and a motor adapted for producing the tractive effort from the motor voltage, the energy source comprising: a heat engine adapted for generating mechanical power by burning a fuel; an alternator adapted for generating an alternating voltage from the mechanical power; a rectifier adapted for rectifying the alternating voltage and producing a low DC voltage; an energy battery adapted for storing and delivering energy derived from the low DC voltage; and a traction boost converter adapted for boosting the low DC voltage to produce the high DC voltage, the motor drive comprising: a power battery adapted for storing energy and delivering power at the high DC voltage; and a traction converter adapted for generating the motor voltage from the high DC voltage during motoring operation and for generating the high

Abstract: A motor drive device, for driving an electric motor having a bearing for rotatably supporting an output shaft, has a drive circuit which drives the motor when a voltage level at a signal input terminal of the drive circuit becomes greater than a threshold value. The voltage level at the signal input terminal becomes greater than the threshold value for a certain period when a power switch is turned on or off.

Abstract: A motor is disclosed that operates on either AC outlet power or DC battery power with decreased power drop when switching between AC and DC power. The AC power to the motor may be stepped down by using a clipper circuit, while the DC power supplied to the motor may be increased by switching motor field windings from a series wound circuit to a parallel wound circuit. The motor may be used in a vacuum motor embodiment, or in other consumer devices that utilize electric motors.

Abstract: The present invention discloses a cooling-fan rotation-speed control circuit, wherein a plurality of sets of input power sources respectively having different voltages is electrically and parallel coupled to a cooling fan; a switch is installed between at least one input power source and the cooling fan; the switch is turned on/off according to a rotation-speed parameter to determine whether the cooling fan is driven by a low-voltage driving power or a high-voltage driving power.

Abstract: A disk drive is disclosed having hybrid spindle speed control. The disk drive includes a disk having a plurality of servo wedges, and a spindle motor for rotating the disk at an operating speed. The spindle motor generates a back electromotive force (BEMF) voltage. In operation, the disk rotation is maintained at the operating speed during a track following operation by updating, in a wedge spindle speed control mode, the spindle control current in response to a wedge speed error. Before executing a high-speed seek, the disk drive is switched to a BEMF spindle speed control mode, and the disk rotation is maintained at the operating speed during the high speed seek by updating the spindle control current in response to a BEMF speed error signal generated based on the BEMF voltage. During a seek-settle time, the disk drive is switched back to the wedge spindle speed control mode.

Abstract: A motor/generator unit in which a motor/generator and an invertor part are integrated and the wiring of a field circuit part for supplying current to a winding on a rotor is rationalized. In a motor/generator unit in which a motor/generator body part having a field winding supplied with electricity via brushes and current-controlled by a semiconductor control device controlled by a control circuit part and an invertor power circuit part controlled by the control circuit part has the invertor power circuit part and the control circuit part mounted thereto, the brushes are disposed between the field winding and the armature winding on one side and the control circuit part on the other and the semiconductor control device is mounted on a control circuit mounting part on which the control circuit part is mounted.

Abstract: A control system and method for controlling the speed of a PSC motor having an auxiliary winding configured to provide torque for initial motor startup and a run winding configured to provide continuous motor operation. The motor is coupled to a capacitor configured to direct a portion of a current through the run winding when the PSC motor reaches its intended speed. The control system includes a speed control unit coupled between a voltage line and the PSC motor and a bypass circuit coupled between the voltage line and the capacitor via a first path. The speed control unit is configured to variably control the speed of the PSC motor. The bypass circuit is configured to receive a control signal from the speed control unit via a second path and to regulate a chopped voltage wave form generated by the speed control unit such that at least a portion of the chopped voltage wave form is not applied to the capacitor.

Abstract: A vehicle propulsion includes an alternating current (AC) traction drive, a first energy storage system electrically coupled to the traction drive through a direct current (DC) link, a second energy storage system electrically coupled to the traction drive such that the voltage output from the second energy storage system is decoupled from the DC link using a bidirectional boost converter, and an energy management system configured to control said first and second energy storage systems when the vehicle is operating in at least one of a pre-charge mode and a normal operation mode with the traction drive system enabled.

Abstract: A motor drive system includes a multi-output dc power source providing three or more output potentials, and a switching circuit including switching devices connected, respectively, with the output potentials of the multi-output power source. A controller determines a command apply voltage representing a desired voltage to be applied to the motor, and further determines a plurality of command share voltages corresponding to supply voltages of the multi-output dc power source, from the command apply voltage. The controller produces a pulsed voltage by driving the switching devices in accordance with the command share voltages.

Abstract: On end of a reactor (L1) is connected to a positive electrode of a battery (B1) and the other end is connected to a power line via a transistor (Q1) and to the ground via a transistor (Q2). By PWM control of the transistors (Q1, Q2), an arbitrary increased voltage is obtained in the power line. It is possible to obtain an optimal inverter input voltage (power line voltage) according to the motor drive state, thereby increasing efficiency. Thus, it is possible to optimize the inverter input voltage according to the motor drive condition.

Abstract: A protective circuit, for reducing electrical disturbances or interference during operation of a DC motor, features a series transistor (62) arranged in a supply lead from a DC voltage source (12) to a DC motor; an auxiliary voltage source (52), associated with that series transistor, having a substantially constant auxiliary voltage which is configured to make the series transistor (62) fully conductive when a supply voltage furnished by the DC voltage source is substantially free of electrical interference; and an analyzer circuit (32, 34, 36) for analyzing the supply voltage, which analyzer circuit is configured, upon the occurrence of electrical interference in the supply voltage, to increase the resistance of the series transistor (62) correspondingly, in order to reduce the influence of that electrical interference on the operation of the DC motor.

Abstract: A power control system (12) for an electric motor having at least one magnetic bearing includes a DC/DC converter (18) supplied from a DC link bus (179) connected to a main power supply (14), the bus (17) supplying power for the electric motor and for a bearing actuator the converter (18) provides low voltage DC power supplies for a motor controller (23), a bearing controller (24) and a supervisory controller (26), the later monitoring the main power supply and communicating with the motor controller (23) and bearing controller (24) so as to cause the motor to operate as a generator in the event of a failure of the main power supply (14) to thereby supply power to the DC link bus (17) to maintain operation of the magnetic bearing. Circuit switching components are connected to the motor winding and selectively switched in a manner causing current generated in the motor winding to flow in one direction into the DC link bus (17) only while the winding voltage is greater than that of the DC link bus (17).

Abstract: An electric machine assembly having an electric machine. The electric machine can include a first speed circuit and a second speed circuit. In some constructions, both speed circuits can be of a permanent split capacitor design. At least one of the speed circuits can include a switch that is controlled by the controller to limit current through an auxiliary circuit of the unused speed circuit when certain conditions exist.

Abstract: An electric drive includes a rotatable shaft, a first drive member, and a second drive member, and is supplied with power from a controller. The controller is operable to supply a first power from a power electronics converter, and a second power that is line power. Supplying the first power individually to the first drive member results in a first shaft speed and first output torque, supplying the second power individually to the second drive member results in a second shaft speed and second output torque, and supplying the first and the second drive members with power at the same time results in a third shaft speed and a third output torque.

Abstract: A rotating electrical machine for a vehicle is capable of improving the acceleration performance and the fuel mileage of the vehicle while achieving the prevention of occurrence of overvoltage and the improvement of its power generation characteristic at the same time. The machine includes an armature having an armature core and an armature winding wound around the armature core for generating an output voltage to charge a battery; a rotor having a rotor core with a field winding wound therearound, and permanent magnets for supplying magnetic flux to the armature core; and a voltage control section that adjust the output voltage of the armature by controlling the field current based on the value of an output voltage of the armature winding and the value and the direction of flow of the field current flowing through the field winding.

Abstract: In a load driving arrangement, electric power is supplied from an auxiliary battery to a main power supply when the power stored by charging in the main power supply is scarce at the startup of the system. The power is supplied to the main power supply by closing relays to connect the auxiliary battery to the neutral point of an auxiliary motor, operating a switching transistor of a bottom arm of an auxiliary-related inverter based on a command from a control circuit, stepping up the voltage from the auxiliary battery by using a coil of the auxiliary motor as a reactor, and supplying the step-up voltage to the main power supply thereby charging the main power supply. At this time, a drive-related inverter and a DC/DC converter are stopped. When the main power supply is charged to a sufficient degree, the relays are opened to drive each load.

Abstract: Power from a high voltage battery (10) (for example 36V) is supplied through an inverter (12) to a motor generator (14). A low voltage battery (20) (for example 12V) is connected through a reactor (18) to the neutral point of the motor generator (14). A voltage ratio of the low voltage battery (20) to the high voltage battery (10) is preferably from 1:2 to 1:4. In order to set the neutral point voltage to a desired charging voltage into the low voltage battery (20), the inverter (12) is controlled so as to follow a current distortion phenomenon. In this way, in a dual-power source system with a voltage ratio of a low voltage battery (20) to a high voltage battery (10) between 1:2 and 1:4, voltage switching means for use in charging a charge voltage of a high voltage side into a low voltage source can be implemented at low cost.

Abstract: A system and method for driving an electric vehicle is provided. The system has, for example, a power source generating a voltage, a voltage converter, a control system, and one or more motors for driving or propelling the vehicle. The voltage converter is configured to accept an input voltage and generate an output voltage, which is different from the input voltage. The power source provides the input voltage to the voltage converter. A switch is further provided to switch the delivery of power to the control system between a power source voltage and an increased voltage derived from the voltage converter.

Abstract: A hybrid electric vehicle having an energy generation system, an energy storage system and at least one electric motor includes a controller for controlling operation of vehicle systems. The controller determines which of a plurality of component configurations is selected. Based upon this determination, the controller establishes the vehicle components in the selected configuration and connected in the selected component architecture. The controller also generates commands based upon this determination to operate the vehicle in a control method corresponding to the determined component configuration. A method for implementing various component configurations is also disclosed.

Abstract: An electric machine assembly having an electric machine. The electric machine can include a first speed circuit and a second speed circuit. In some constructions, both speed circuits can be of a permanent split capacitor design. At least one of the speed circuits can include a switch that is controlled by the controller to limit current through an auxiliary circuit of the unused speed circuit when certain conditions exist.

Abstract: Advances in electric power storage, monitoring, control and use in electric motors are described from the viewpoint of their optimal use in electric watercraft. Electric motor overspeed capability is provided to allow a wider range of performance from electric motors. Monitors and useful ways of constructing electric power supplies such as cost performance monitored batteries for electric motors and hydrogen absorbent chambers for fuel cells are further described. Such devices and methods provide greater efficiencies, greater convenience and improved flexibility for operators and riders of watercraft, land vehicles, airplanes and other devices.

Abstract: An electric vehicle drive has an electric machine which can be alternatively driven as a motor or as a generator and has a d.c. connection to which a supply voltage can be applied, from a first energy source and/or a second energy source. The first energy source is designed for base load supply of the electric machine, while the second energy source comprises an energy accumulator designed for a short-term peak load supply of the electric machine. Also, vehicle braking energy can be stored by way of the electric machine in its generator operating mode. According to the invention, the second energy source in the form of an energy accumulator is coupled via a bidirectional DC/DC converter to a supply connection of the first energy source connected with the direct-voltage connection of the electric machine.

Abstract: A method for controlling an electromagnetic actuator having an arm connected thereto uses a circuit that temporarily places in a high impedance state output nodes connected to a winding of the electromagnetic actuator. A detected BEMF is compared with a lower threshold and an upper threshold. Current in the electromagnetic actuator is monitored and controlled. A current pulse is provided to the electromagnetic actuator based upon the comparison of the detected BEMF with the lower and upper thresholds. The respective amplitudes of successively provided current pulses having a same polarity are progressively increased, and an amplitude of a provided current pulse having a polarity opposite a polarity of a preceding current pulse is decreased. The amplitude of the driving current pulses provided to the winding of the electromagnetic actuator advantageously adapts automatically to varying frictional conditions, or to any other cause of variation of the mechanical load of the actuator.

Abstract: A disk drive is connectable to a power supply having a fixed DC voltage. The disk drive includes a voice coil motor (VCM) and a spindle motor having a plurality of windings and a rotor rotatable at a variable spin-rate. A spindle motor driver is coupled to the fixed DC voltage and at least one of the windings for controlling the spin-rate of the rotor. The rotor has permanent magnets that induce an AC voltage across the windings while the rotor is rotating. A rectifier circuit rectifies the AC voltage across at least one of the windings to produce a rectified DC voltage. A first switch provides the rectified DC voltage to a first node. A second switch provides the fixed DC voltage to the first node. The first node has a first node DC voltage that is determined by the rectified DC voltage provided by the first switch and the fixed DC voltage provided by the second switch. The first node DC voltage is greater than the fixed DC voltage during a track seeking operation in the disk drive.

Abstract: A disk drive is connectable to a power supply having a fixed DC voltage. The disk drive includes a voice coil motor. The fixed DC voltage is supplied to a first node. A capacitor is coupled between the first node and a second node and is charged to approximately the fixed DC voltage by grounding the second node while the disk drive performs a track following operation. The DC voltage of the first node is increased to an increased DC voltage greater than the fixed DC voltage by providing the fixed DC voltage to the second node while to the disk drive performs a track seeking operation. The first node is de-coupled from the fixed DC voltage while the DC voltage of the first node is greater than the fixed DC voltage. The DC voltage of the first node is provided to the voice coil motor. The increased VCM voltage allows faster access times and more efficient VCM operation.

Abstract: A motor driving circuit coupled to a motor having a plurality of phases of coils includes a standard power source generating a first power supply voltage, and a step-up power source for generating a second power supply voltage greater than the first power supply voltage. A selecting circuit selects either the first power supply voltage or the second power supply voltage in response to a selecting signal. A motor driving circuit causes currents to flow in the phases of the motor in accordance with motor driving signals respectively related to the phases in a state in which a selected power supply voltage output by the selecting circuit is applied to one or more phases. A switching unit generates the selecting signal on the basis of the motor driving signals and a voltage signal corresponding to a current flowing through at least one of the phases of the motor so that the second power supply voltage is selected first and the first power supply voltage is selected second with respect to each of the phases.