Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Hideaki Mori

Yasunori Yamamoto

Makoto Gotou

Shinichi Kuroshima

Masaaki Ochi

Yoshiaki Igarashi

Shingo Fukamizu

Go Takata

Masaki Tagome

Hisanori Nagase

Hideki Nishino

Daisuke Ito

Hiroki Kobayashi

Toshiyuki Murakami

Susumu Yamamoto

Taishi Iwanaga

Maki Murakami

Akira Maeda

Hideo Nobekawa

Noriaki Emura

Keiji Nishihara

A light receiving sectionreceives a measurement beam, which is cast from a light projection sectionand partially blocked by cream solderscraped up by a squeegee, whereby a sensormeasures a one-dimensional size of a predetermined region of a cross sectional profile of the cream solderas a cross sectional paste length and takes the cross sectional paste length as an index for an amount of residual cream solder. The amount of residual cream soldercan be numerically grasped at all times, so that versatility and accuracy in detecting the amount of residual cream soldercan be assured.

Screen printer and method for detecting amount of residual paste

In a back electromotive force phase detecting device, a timing generating unit generates a timing signal indicating a start timing, an intermediate timing and an end timing of a 180-degree electrical angle period in a detection target phase, from an excitation pulse signal. A difference calculating unit receives the timing signal, and calculates a difference between a total PWM control period of the detection target phase during a first-half 90-degree period, and a total PWM control period of the detection target phase during a second-half 90-degree period. In an excitation control device, a control unit changes the capability of driving a motor based on an output of the back electromotive force phase detecting device.

Device and method for detecting back electromotive force phase and device and method for controlling excitation

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 () according to the present invention turns ON all of one-side drive transistors selected from the high-side drive transistors (and) and the low-side drive transistors (and) of power supply means () 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.

Motor drive apparatus and motor drive method

Problems with accuracy reading position detection signal peaks and minute phase differences in the detection current make motor drive control easily susceptible to differences in motor characteristics. The rotor position is determined based on whether or not a terminal difference voltage, which is the difference voltage between the motor terminal voltage and the pseudo-neutral-point voltage when the motor phases are selectively energized, exceeds a specific threshold value. The phase energized to start the motor is determined based on this determination and the motor is energized accordingly to start. Instead of switching directly from the search step at the initial rotor position to the back-EMF voltage mode, a search and start mode that creates initial rotor speed sufficient to start the motor is executed before entering the back-EMF voltage mode.

Motor drive device and motor drive method

A motor driving apparatus includes a virtual difference voltage detecting unit operable to detect a difference voltage between a virtual neutral point of a resistor circuit connected in parallel to motor coils and a terminal of a motor coil in non-conduction state, a rotor position detecting unit operable to detect a position of the rotor based on the difference voltage, and a controller operable to control commutation of an inverter based on the rotor position. The motor driving apparatus has a searching start mode for detecting the rotor position and energizes the coils, and a back electromotive voltage feedback mode for controlling commutation based on the back electromotive voltage. In the searching start mode, a rotor position searching process and a rotation start torque applying process are alternately performed.

Motor driving apparatus, motor driving method and disk driving apparatus

A motor drive apparatus and motor drive method reduce vibration and acoustic noise by not requiring a non-activation period for rotor position detection, and enable stable, high efficiency motor drive. A control voltage generator generates a control voltage based on the frequency of the speed signal FG output from a speed detection unit, and the amplitude of the control voltage is controlled based on a torque control signal EC. The phase difference generator detects the phase difference between the control voltage and the zero cross signal of the motor current detected from the motor terminal voltages. A control voltage generator controls the phase of the control voltage so that the phase difference goes to zero, thus accomplishing sensor-less motor drive.

A reverse current detection unit detects the direction of the motor current during the synchronous rectifier period based on the polarity of the on voltage of a switching device contained in the motor current path, and outputs a reverse current detection signal representing the result of this detection to the PWM control unit. Change in the output of the PWM control unit that generates the drive signal for a particular switching device in the drive unit is controlled based on the reverse current detection signal and the energizing pattern of the drive unit is changed when motor current is detected in the synchronous rectifier period to be flowing in the opposite direction as in the urging period. The flow of motor current to the power supply is thus reduced and a rise in the power supply voltage can be prevented.

Motor drive device and drive method

A rise in the power supply voltage as a result of a sudden speed reducing command causing the motor current to flow to the power supply is prevented. The motor drive device has a drive signal generating unit for generating a drive signal by an energizing control unit, PWM control unit, and oscillation unit; a drive unit for producing drive power to drive the motor based on the drive signal; a torque control signal generating unit for generating a torque control signal specifying the motor torque; a speed detection unit for detecting the rotational speed of the motor and generating a rotational speed signal denoting motor speed information; and a decision unit for generating a speed difference detection signal denoting the difference between the torque control signal and the rotational speed signal. The drive signal generating unit is controlled based on the speed difference detection signal.

A motor driving part has half bridge circuits in which a high potential side drive transistor and a low potential side drive transistor are connected in series to each other, and a connection point therebetween serves as a stator winding driving terminal of each phase of a motor. A rotor position detector detects a rotor position of the motor and outputs a rotor position signal. The current phase detector detects the phase of a phase current flowing in the stator winding driving terminal. A voltage signal generator controls and generates a voltage profile signal such that a first phase difference that is a difference between the phase of the phase current and the phase of the rotor position signal is kept to a predetermined electrical angle. A driving signal generator generates a PWM signal that drives the drive transistor of each phase depending on the voltage profile signal.

Motor driving device, motor driving method, and motor apparatus

A rotor position sensorless multiphase motor driving device includes a rotor; a plurality of phase windings; a common terminal to which one terminal of terminals at both ends of each winding is star connected; an upper-side drive transistor and a lower-side drive transistor connected to the other terminal of the winding; a commutation control unit operable to select two terminals other than the common terminal of the windings, and to turn on the corresponding pair of upper-side drive transistor and the lower-side drive transistor; a rotor position search pulse applying unit operable to apply a search pulse to the selected two terminals; and a comparing unit operable to detect a rotor position based on a response signal generated between the terminal which was unselected and the common terminal according to the search pulse application.

Motor driving device and motor driving method

A Motor driving apparatus adjusts activation start timing of high-side activation control signals UU, VU, WU and the low-side activation control signals UL, VL, and WL with a state determination signal SJ in an activation controller, in the period from starting to the time when rotor rotating speed reaches a predetermined value, sets the activation start timing earlier than in normal times to perform leading phase activation control, and in normal times when the rotor rotating speed is a predetermined value or more, controls activation start timing in efficient and optimum phase. Hence, the motor driving apparatus can carry out stable PWM sensorless starting without any starting failure such as oscillation, loss of synchronism and reverse rotation and shorten starting time.

Motor driving apparatus

A motor driving apparatus includes a motor driver which includes a parallel circuit in which a plurality of series circuits are connected in parallel. Each of the plurality of series circuits has a high side switching device and a low side switching device connected in series. A voltage detector detects a voltage at a neutral point of the multiphase motor and outputs the detected voltage as a first detection signal. A timing detector detects a timing at which a voltage of the first detection signal equals to a reference voltage, and outputs the detected timing as a second detection signal which is used to generate a plurality of driving signals for driving switching devices in the parallel circuit.

Apparatus and method for driving the multiphase motor using the magnetic pole position detector

A motor driver drives a motor composed of a rotor and plural-phase windings that generate a magnetic field for rotating the rotor, including: a plurality of transistors that operate as switches for supplying current to the windings; a position detector operable to detect a rotational position of the rotor, based on a terminal voltage of each winding; and a switching controller operable to have performed a switching method to turn the transistors to an ON state or to an OFF state for controlling the rotor at the predetermined speed by means of the position detector, wherein the switching controller further controls so as to force each of the transistors into the OFF state for a predetermined duration in a predetermined cycle, and the position detector detects only while the switching controller forcedly keeps the transistor in the OFF state.

Motor driver

A motor driving apparatus includes a comparator, a threshold controller, a position determining unit, a phase-switching controller, and a current output unit. While the rotor is stopped, the phase-switching controller supplies a predetermined phase of winding with a current pulse having a predetermined pulse width so as not to cause the rotor to react and operate, in order to determine the initial position of the rotor. The position determining unit determines an initial position of the rotor based on the result of comparison between the induced voltage generated in a non-conduction phase by the current pulse and the threshold. The phase-switching controller performs energization or commutation according to the determined initial position of the rotor to start up the motor.

Motor driving apparatus and motor driving method

In a motor and a disk drive apparatus in accordance with the present invention, a position detecting partcomprises a detection signal switching circuitA, a noise elimination circuitand a detection circuitB, and the detection signal switching circuitA is configured to output an inverted detection signal obtained by logically inverting a detection signal until the rotation speed reaches a predetermined rotation speed after the beginning of starting or until a position detection pulse signal FG is detected a predetermined number of times; position detection operation is carried out only during the ON operation of PWM, whereby PWM sensorless starting is carried out.

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Nishinomiya, Japan

Hideaki Mori