Matsushita Electric Industrial Co., Ltd.

Hiromitsu Nakano

Masahiro Yasohara

Isao Yoshida

Yoshitsugu Kimura

Toshiaki Seima

Hiroshi Dohi

Hiroyuki Oku

Muneo Yamamoto

Mitsuharu Ota

Tomohiro Inoue

Hiroshi Minakuchi

Akihiko Watanabe

Yukio Honda

Susumu Yamamoto

Kenichi Kishimoto

Hisataka Kato

Kazutsugu Kobayashi

Toshiki Tsubouchi

Kenichiroh Takahashi

Yoshio Tetsugu

Tomio Oyama

Sotomitsu Maeda

Mitsuru Yamane

A motor driving power supplying section obtains an output voltage by switching-controlling a predetermined voltage outputted from a main power supply and smoothing a voltage thus switching-controlled. A driving transistor group includes a plurality of driving transistors, for supplying electric power based on the output voltage of the motor driving power supplying section to the motor driving coils of multiple phases. A commutation control section supplies conduction switching signals to the driving transistor group so as to switch successive conduction states of the motor driving coils. An output control section controls the output voltage of the motor driving power supplying section so that a collector-emitter voltage of at least one of the plurality of driving transistors included in the driving transistor group has a predetermined value. A torque control section controls conduction current intensity to the motor driving coils by controlling output currents of the plurality of driving transistors included in the driving transistor group.

Control device for a brushless motor

In a motor control apparatus for controlling a rotational position of a motor, a rotation detector detects the rotational position of the motor, and outputs first and second detection signals having phases corresponding to a detected rotational position of the motor and different from each other, and a position detecting circuit detects a rotational position in a unit which is less than one cycle of the first and second detection signals based on the first and second detection signals, and outputs a rotational position signal representing a detected rotational position. Further, a motor controller compares the rotational position signal with a reference position signal representing a reference rotational position of the motor to obtain a position error, and controls the rotational position of the motor so that the position error is minimized.

Motor control apparatus equipped with a controller for controlling

With a view to reduce vibrations generated by a motor and improve resistance to heat, reliability and vibration isolation properties without increasing the cost or the number of manufacturing steps in a rotor for a permanent-magnet motor, a rotor core is formed of an outer peripheral portion by which the permanent magnet is fixed, and a central portion by which a shaft is fixed, a clearance is provided between the outer peripheral portion and the central portion, and the outer peripheral portion is connected to the central portion by means of a plurality of fastening members. Thus, a rotor having excellent vibration isolation properties can be obtained. Since the rotor core is formed of laminated iron plates on which the outer peripheral portion, the central portion and the fastening members are all formed as one piece, resistance to heat, reliability and the vibration isolation properties can be enhanced without increasing the cost or the number of manufacturing steps.

Rotor for a permanent-magnet motor

A drive apparatus for use in a brushless motor with a rotor and a drive coil assembly. The drive apparatus comprises an energization-state instruction circuit for generating an energization-state instruction signal instructing an energization state of the drive coil assembly on the basis of the position detection signal indicative of a position of the rotor and an energization switching circuit for outputting an energization switching signal to successively switch the energization state of the drive coil assembly in accordance with the energization-state instruction signal and a duty control signal. A power circuit is coupled to a direct-current voltage source and is responsive to the energization switching signal so as to energize the drive coil assembly by means of a direct-current voltage from the direct-current voltage source in accordance with the energization switching signal therefrom. A duty control circuit is responsive to a speed instruction signal from a speed instruction circuit and a motor speed signal from a speed detecting circuit for outputting the duty control signal to the energization switching circuit so as to control a duty ratio of the energization-state instruction signal on the basis of the duty control signal so as to output the energization switching signal to be inputted to the power circuit.

Drive apparatus and speed control apparatus for brushless motor

Drive device for a brushless motor

In a system for driving a brushless motor having motor drive coils connected to respective drive transistors, voltages induced in the drive coils when the motor is rotating are continuously detected to produce energization switching signals to be applied to the drive transistors, thereby switching over energization of the drive coils, so that the motor can be continuously driven at optimum energization timing regardless of its rotational speed. Further, when a rotational direction command signal is applied to a forward-backward switching circuit to instruct the motor to rotate in the backward rotational direction while the motor is rotating in the forward rotational direction, torque of the opposite direction is produced to change the rotational direction of the motor. Further, separate-excitation timing pulse signals are used to sequentially switch over energization of the motor drive coils when the motor is not rotating or it is rotating at a very low speed, and hence voltages induced in the motor drive coils cannot be detected. As soon as the voltages induced in the drive coils have become able to be detected due to the rotation of the motor, self-excitation timing pulse signals are then used to sequentially switch over energization of the drive coils.

Brushless motor driving system

Brushless motor drive device

A system for driving a brushless motor comprises motor drive coils belonging to a plurality of phases respectively, a plurality of pairs of drive transistors connected to the drive coils respectively, a distribution circuit for sequentially distributing drive-coil energization switching signals to the plural drive transistors respectively, a slope synthesizer for smoothing leading and trailing slope portions of the drive-coil energization switching signals so as to apply the smoothed energization switching signals to the drive transistors respectively through the distribution circuit, a voltage-controlled oscillator for supplying a signal having a suitable frequency as an input to the slope synthesizer, a phase error detector for detecting the phase difference between counter-electromotive voltages induced in the drive coils and the drive-coil energization switching signals in a driver-coil energization pause period, and an error amplifier for amplifying the output signal of the phase error detector and applying the amplified phase error signal as an input to the voltage-controlled oscillator.

System for driving a brushless motor

A phase difference between a counter-electromotive voltage induced in a driving coil and a voltage which is applied to the driving coil is detected by comparison of a terminal voltage of the driving coil and a reference voltage. A frequency of a voltage-control oscillator which controls switching of the voltage applied to the driving coil is varied by an output signal made by the comparison, and the phase difference is controlled to be reduced to zero.

Driving apparatus for brushless motor

A speed control apparatus for a motor, wherein the counter-electromotive voltage is detected with great precision even when the counter-electromotive voltage to be caused from the motor driving coils is small or the ambient temperature is changed. The voltages corresponding to the detection voltages are turned into speed signals. The emitter resistance of the driving transistor, which is the cause of the torque reduction, can be removed, and uneven rotation, uneven torque is reduced. The speed control apparatus provides a composite voltage of driving coil voltages that are converted by an inversion amplifier. The voltage corresponding to the composite voltage provides the speed signal. This voltage is transferred to the driving coils and precise speed control is produced without a reduction in the controllable maximum torque or the starting torque.

Speed control apparatus for a motor

A speed control apparatus for a DC motor operable with a low voltage battery has a reference voltage generating circuit capable of operable with a low voltage such as 1 V and is settable for output voltage and for temperature coefficient independently each other and has a differential amplifier which is operable with a very small input voltage and capable of operable with such a low voltage.

Speed control apparatus for a DC motor

A speed control apparatus for DC motor (1), comprises a bridge circuit formed by the winding of the motor (1), a resistor (2) series thereto, and two resistors (3 and 4). Therein, a reference voltage (E.sub.r) is produced by dividing a voltage V.sub.ref of a constant voltage circuit (20) by a divider network (21+22). The voltage difference this reference voltage (E.sub.r) and a voltage produced across the detection output terminals 'a' and 'b' which is proportional to a counter electromotive force (E.sub.a) of the DC motor (1) is amplified by a differential amplifier (23+24). A current mirror circuit is formed by transistors (16), (17) and (18). The first transistor (16) regulated of its collector current (I.sub.r) by a constant current circuit (19) controls collector current of the second transistor (17), which controls input current of the constant voltage circuit (20). The third transistor (18) regulated of its collector current constantly controls the input current to the differential amplifier (23+24) for controlling the transistor (7) to control the motor current.

Speed control apparatus for DC motor

An overcurrent protection apparatus for a DC motor which can be used with a speed control system of a DC motor to prevent an overcurrent condition arising when the DC motor is run with a heavy load or locked by an overload from burning or overheating windings of the motor. The apparatus is constructed using at least one integrated circuit and includes a current mirror circuit for detecting an overcurrent and for cutting off the supply current of the DC motor. A timing circuit prevents overcurrents lasting only a short time from triggering the apparatus to shut down the motor. Once the apparatus is triggered to shut off the motor, the motor will remain off for an indefinite period of time until the apparatus is reset.

Overcurrent protection apparatus for DC motor

Speed control apparatus for DC motor comprising a current mirror circuit including a first transistor 11 and second transistors 12-14 with their bases connected in common, the collectors of the second transistors 12-14 being in-common connected to one end of the DC motor 9 so as to control the motor current, the bases of the transistors being fed with such base current that saturates the transistors, thereby to raise their maximum controlling torque and starting torque of the DC motor.

A speed control system for a d-c electric motor comprising a three-terminal space control IC to provide a constant voltage source having a negative internal resistance equal in absolute value to the internal resistance of the motor and thereby render the motor rotatable at a constant controlled speed. A resistance element having a positive temperature coefficient is used as an external circuit element for the IC so that rotation speed variations relative to load torque variations will be substantially constant despite variations in the ambient temperature.

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Hirakata, Japan

Hiromitsu Nakano