This invention provides a brushless DC motor which does not have a position sensor for detecting a rotational point of a rotor. Instead of using a position sensor, zero-crossing points of counter electromotive forces induced in the stator windings of the rotor are detected to obtain a pulse signal train. From the pulse signal train thus obtained and a slant waveform signal generated in response to the pulse signal train, a position signal with a trapezoidal waveform is formed. An electric current signal with a trapezoidal waveform is supplied to the stator windings of the rotor in response to the position signal thus formed for effecting an electric current switching of the stator windings smoothly, resulting in realizing a motor drive less in vibration and noise even when rotating at a high speed.

Brushless DC motor

A drive system is provided for a utility vehicle and includes an alternating-current (AC) motor for providing a drive torque. An AC motor controller receives a battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, forward/neutral/reverse (FNR) signal, and run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed. The AC motor controller generates an AC drive signal for the AC motor, wherein the AC drive signal is based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

Ac drive system for electrically operated vehicle

A control for a brushless generator is operable in a starting mode of operation to convert electrical power into motive power for starting a prime mover. The control applies AC power to an exciter field winding at a first frequency at the initiation of a start sequence and thereafter decreases the frequency of the power applied to the exciter field winding during the start sequence.

Starter/generator system with variable-frequency exciter control

A control system (100) for a five-phase brushless DC motor (102) including a stator having five windings and a rotor (116) mounted for rotation relative to the windings (114). The windings (114) are adapted to be electronically commutated in response to the rotary position of the rotor (116). The control system (100) includes a sensing circuit (106) to sense the rotary position of the rotor (116) using an optical or magnetic sensor or the back electromotive force voltages in the windings (114). Electronic switches (112) control the flow of current through the windings (114) in response to control signals generated by a control circuit (110) in response to the rotary position of the rotor (116). The control circuit (110) includes start-up logic to start the motor (102). If the rotor (116) is rotating in a wrong direction upon start-up, the control circuit (110) energizes preselected windings (114) and waits for the movement of the rotor (116) to come substantially to a stop and then energizes the windings (114) in a start-up sequence to cause the rotor (116) to rotate in a correct direction. Once the rotor (116) is rotating in the correct direction, the control circuit (110) electronically commutates the windings (114) in response to the rotary position of the rotor (116).

Control circuit for five-phase brushless dc motor

A suspension control system employs a road sensor monitoring road roughness or smoothness and producing a road condition indicative signal The control system also employs other sensor or sensors for monitoring at least one preselected suspension control parameter, such as vehicle speed, steering angular variation and so forth, other than road roughness The suspension switches between relatively hard and relatively soft characteristics based on the preselected suspension control prameters In order to make suspension control more precisely suited to the vehicle driving conditions, the control characateristics of the suspension system are adjusted depending upon the road condition With this arrangement, even when the suspension is controlled so as to suppress vehicular roll based on the steering angular displacement and when rough road conditions cause steering angular displacement due to kick-back from the road input through the steering mechanism, the erroneous judgement that steering adjustments are about to cause vehicular roll can be avoided In case of acceleration responsive suspension control, rough road conditions tend to cause a driver to unconsciously operate the accelerator pedal so as to increase and decrease throttle valve angular position relative to the fully closed position According to the present invention, by adjusting the control characteristics, erroneous detection that the vehicle is accelerating, which would normally cause winding-up, can be successfully avoided

Method and system for controlling automotive suspension system, particularly for controlling suspension characteristics in accordance with road surface conditions

A resilient coupling between the rotor and output shaft of a brushless DC motor cooperates with a sensorless drive arrangement that obtains rotor position information from the voltage induced in the stator windings of the motor to reduce the effective inertia of the load and aid in starting of the motor

Brushless DC motor and sensorless drive arrangement therefor

A motor driven air moving apparatus adapted to high speed, constant duty operation has a DC permanent magnet motor with a stator and rotor, one having a wound core with an even number of identically sized, evenly spaced teeth and the other having an even number of identically sized, permanent magnet poles. One of the rotor and stator has a skew at an angle from the axial, the maximum achievable skew being less than one tooth pitch due to short axial core width. A groove is provided along the midline of each of the teeth of the core which is parallel to and shallower than the tooth separating slots and contains no winding. The groove is effective to divide the tooth magnetically in half and thus decrease the effective tooth pitch, whereby, simultaneously, the magnetically induced pulsating angular velocity of the rotor and resultant audible noise are reduced and the system efficiency of the motor and air moving apparatus combination at high speeds in constant duty operation is increased.

Motor driven air moving apparatus for high speed, constant duty operation

The speed command for an open-loop brushless motor speed control system is overridden whenever the speed of the motor is less than a relatively low reference speed in order to quickly accelerate the motor to a running speed, despite a relatively low speed command. In the event of a motor overcurrent condition, the override is itself overridden to protect the controller.

Open-loop brushless motor control system

A washer system for transparent surfaces such as headlamp lenses and windshields has a liquid delivery chamber of a predetermined volume which is supplied with liquid through a one-way valve from a liquid storage chamber having a larger predetermined volume. The liquid in the delivery chamber is expelled from the chamber through passages and nozzles by air pressure which is stored at high pressure in an accumulator. The air in the accumulator is controlled for selective delivery by the operator. The accumulator is replenished with air automatically by an air compressor. A pneumatic delivery passage is connected between the top of the liquid delivery chamber and the nozzle passages to assist in exhausting the liquid in the passages through the nozzles and after the liquid is expended to permit air in the chamber to escape during refilling of the chamber with liquid.

Washer system for transparent surfaces on a vehicle

The control circuitry of a brushless blower motor is mounted on the stator of the motor and is cooled during operation of the blower by a portion of the air moved by the blower. A rotor cup member which covers and protects the control circuitry has at least a pair of radially displaced openings formed therein, and air is conveyed through the openings due to an air pressure differential therebetween created by the movement of air by the blower.

Jack W. Savage

Papers

Brushless DC motor and sensorless drive arrangement therefor

Motor driven air moving apparatus for high speed, constant duty operation

Open-loop brushless motor control system

Washer system for transparent surfaces on a vehicle

Brushless blower motor with load proportional cooling for control circuitry