Abstract: A method and system for early detection of incipient faults in an electric motor are disclosed. First, current and voltage values for one or more phases of the electric motor are measured during motor operations. A set of current predictions is then determined via a neural network-based current predictor based on the measured voltage values and an estimate of motor speed values of the electric motor. Next, a set of residuals is generated by combining the set of current predictions with the measured current values. A set of fault indicators is subsequently computed from the set of residuals and the measured current values. Finally, a determination is made as to whether or not there is an incipient electrical, mechanical, and/or electromechanical fault occurring based on the comparison result of the set of fault indicators and a set of predetermined baseline values.

Abstract: A sensorless vector control system of an induction motor includes: a magnetic flux and speed controlling unit for receiving a predetermined command value and generating two phase voltages of DC component; a first reference frame converting unit for converting the two phase voltages of DC component into three phase voltages of AC component; an inverter for receiving the three phase voltages of AC component and driving an induction motor; a current detecting unit for receiving the three phase power of AC component flowing between the inverter and the induction motor, and detecting and outputting three phase currents of AC component; a second reference frame converting unit for receiving the three phase currents of AC component, and converting and outputting two phase currents of DC component; a magnetic flux and speed estimating unit for receiving the two phase voltage of DC component and the two phase currents of DC component, estimating a magnetic flux and speed required for a vector control; and a primary re

Abstract: Method and system for controlling the start of a permanent magnet machine are provided. The method allows to assign a parameter value indicative of an estimated initial rotor position of the machine. The method further allows to energize the machine with a level of current being sufficiently high to start rotor motion in a desired direction in the event the initial rotor position estimate is sufficiently close to the actual rotor position of the machine. A sensing action allows to sense whether any incremental changes in rotor position occur in response to the energizing action. In the event no changes in rotor position are sensed, the method allows to incrementally adjust the estimated rotor position by a first set of angular values until changes in rotor position are sensed. In the event changes in rotor position are sensed, the method allows to provide a rotor alignment signal as rotor motion continues. The alignment signal allows to align the estimated rotor position relative to the actual rotor position.

Abstract: A motor rotational pulse generating circuit for a motor is provided which generates a correct pulse signal even at an initial turning-on stage of the motor, by adjusting a filter cutoff frequency in response to motor rotational condition. The motor rotational pulse generating circuit includes a rotational pulse generation circuit 20 which generates ripple pulses based on a signal being inputted from the DC motor 1, in which a ripple is superposed whose frequency is in proportion to a rotation number of the DC motor 1. A filter 3 makes a cutoff frequency variable on the basis of a clock signal issued from a PLL circuit 6. An oscillation frequency at an oscillator VCO10 is determined by the ripple pulses and a motor rotation condition signal inputted by way of circuits 12 to 16 inclusive. A microcomputer 20 operates, when the motor is turned on, to cause the oscillator VCO10 to issue a preliminary clock signal.

Abstract: A motor controller drives a motor based on signals from commutation sensors (CS signals.) This controller includes (a) a pole position detector for detecting a rotor pole position with edges of the CS signals; (b) a speed detector for detecting a motor speed based on a time interval between the edges of the CS signals; (c) a pole phase detector for estimating a position angle of the rotor based on an output from the position detector and an output from the speed detector; and (d) a phase limiter for restraining the estimated position angle from advancing over a given value. When the limiter continues operating for a certain interval, the controller switches the motor from sine wave driving to rectangular wave driving. This structure allows this controller to drive the motor stably when the motor speed is abruptly changed in the sine wave driving or under field weakening control.

Abstract: When the amount L of actual load change that is picked up from an external plant control device exceeds a reference level L* of load change amount per prescribed unit time that is pre-set to serve as an impact drop detection level, the d axis field current Id is suppressed to a prescribed limiting amount. The d axis voltage reference Vd* and hence the motor and armature voltage Eac are thereby suppressed exclusively during a prescribed field limiting period Td. A large potential difference (voltage margin) is thereby generated between the converter output voltage Vac and AC motor armature voltage Eac, thereby speeding up the rise of output current of the motor. Subsequent recovery of the motor speed after impact drop is speeded up by returning the voltage level to the original d axis voltage reference Vd*.

Abstract: A motor apparatus, such as a DC brushless motor, is provided for the obtaining a position detection signal by detecting the intersection of the divided voltage of a bus voltage and three phases of the divided voltage of the three phases by a comparator which results in the central position of a flat portion. For the divided voltage for the three phases of the respective positive terminal of the comparator, the comparison voltage obtained by dividing the voltage between the divided voltage for the three phases of the following phase in the order and the divided voltage of the bus voltage is applied to the respective negative terminal. As the comparison voltage is phase shifted, the position can be detected by making a slant position ahead of the flat point of the intersection.

Abstract: The present invention provides a control algorithm which instantaneously detects magnetic pole positions in the inside of a motor including polarities of the motor. A controller 1 applies a minute voltage change vhd to a voltage command on a dc axis which constitutes an estimation magnetic pole axis of the motor 3, detects electric currents Idc, Iqc of a motor 3 and discriminates the polarities of the magnetic pole axes by making use of the difference between a cycle in which ripple components of the electric currents Idc, Iqc become positive and a cycle in which the ripple components become negative or the difference between positive-side and negative-side current change rates. Further, the minute voltage change vhd with respect to the above-mentioned voltage command is generated on both of the dc axis and the qc axis rectangular thereto, and the magnetic pole positions of the motor are directly estimated based on the current ripple components on the respective axes.

Abstract: A sensorless vector control apparatus includes a speed controller for receiving a speed command value from a user and outputting a synchronous speed; a ‘d’ and ‘q’ axis voltage command unit for receiving the synchronous speed and outputting a ‘d’ axis voltage and a ‘q’ axis voltage; a voltage converter for receiving the ‘q’ axis voltage and the ‘d’ axis voltage, and converting the two phase voltages into three phase voltages; and an inverter for receiving the three phase voltages and controlling a speed of an induction motor. Since the vector control may be performed over the whole velocity range without using a speed sensor, the sensorless vector control apparatus may be used with advantage.

Abstract: An H-bridge motor driving circuit has, between a PWM comparator and a control circuit, first and second frequency dividers for frequency-dividing, by 2, an AND gate, OR gate, and first and second and second inverters. During a first period, the first and second MOS transistors are turned on, and the second and third MOS transistors are turned off, caused a current to flow through a motor. During a next second period, the third and fourth MOS transistors are turned on, and the first and second MOS transistors are turned off, causing a regenerative current to flow through the motor. During a next third period, the MOS transistors are turned on and off in the same manner as during the first period, causing a current to flow through the motor. During a final fourth period, the first and second MOS transistors are turned on, and the third and fourth MOS transistors are turned off, caused a regenerative current to flow through the motor.

Abstract: A feedback gain K is determined by using an estimation error ei of a stator current, and an observed flux and an estimated speed are obtained and output based on the feedback gain K. An induction motor is controlled based on the observed flux and the estimated speed. In this way, a control system, an observer, and a control method, which realize a global stable control of an induction motor drive that does not comprise a speed sensor and/or a rotational position sensor, are implemented.

Abstract: The present invention overcomes the disadvantages of previously known motor controllers for centrifuge machines wherein a motor controller is provided for a centrifuge machine including a logic control module, one or more power cells, and one or more contactors. The logic control module is capable of interfacing with the main centrifuge controller and provides control over the power cells and contactors to provide a voltage ramp-up to accelerate the centrifuge basket. As such, the logic control module avoids the current draining problems associated with across the line starting of the centrifuge motor. The power cells receive a voltage from the main power supply, and output to the contactors variable power to control centrifuge motor speed. Further, the configuration of multiple contactors to reverse the power supplied to the centrifuge motor windings may eliminate the need for a second, reverse direction motor.

Abstract: A method and apparatus for achieving constant air flow rate economically utilizes an induction blower motor with control settings determining the motor excitation voltage. A memory stores, for a variety of motor speeds, a graph of the speeds plotted against a proportionality constant of flow rate to fan speed for the selected motor system on one axis and motor control settings on the other axis. The only monitoring necessary to achieve the constant flow rate is thus the sensing of fan rotational speed. The measured fan speed is compared against the proportionality constant needed for the selected constant air flow rate and a motor excitation voltage is derived to achieve that proportionality constant. When the system load changes significantly, thereby causing significant fan speed change, a cascaded control loop is used whereby the speed changed induced by each control voltage adjustment is monitored until the desired constant flow rate is again attained at the new load level.

Abstract: A method and apparatus for controlling the torque of and reducing torque ripple in a permanent magnet motor without using current sensors. By eliminating the need for current sensors, low frequency torque ripple is reduced. A voltage mode control method is implemented to control the motor. In response to the position and speed of the rotor and a torque command signal, a controller develops motor voltage command signals indicative of the voltage required to produce the desired motor torque. A rotor position encoder determines the angular positions of the rotor. From the angular positions of the rotor, a speed measuring circuit determines the speed of the rotor. The position and speed signals are applied to the controller. The controller uses this information and develops the motor voltage command signals indicative of the voltage needed to produce the desired motor torque. An inverter is coupled between a power source and the controller.

Abstract: An energy efficient low-power integral electronically commutated fan motor and control circuit assembly mounted on a circuit board for use in refrigerators utilizing a Hall sensor to provide positional control signals for sequential energization of the windings with the Hall sensor energization being pulsed, and the motor stator windings energized only during a portion of the period, when rotational torque produced by the energization is greatest in order to reduce the power input to the assembly. Integrally molded multi-function components including the coil bobbin, ground pin, Hall sensor holder, motor bearing oil well covers, and assembly housing provide positioning, support, and securing assistance along with electrical and magnetic operative connections and positioning.

Abstract: A control apparatus for an electric vehicle is provided, which is capable of reducing the weight of the electric vehicle and preventing the inverter circuit from overheating. When the vehicle stops on an uphill due to stalling, the control unit 30 starts counting the time over which current is supplied through the same IGBT element. When the count value reaches a value corresponding to the time at which the IGBT 40 starts generating heat, the control unit 30 outputs a control signal to reduce the motor driving current to the IPM 20. The rotation sensor 60 detects the rotational position when the motor rotates in the reverse direction, while the reduction of the motor driving current reduces the driving power of the motor. Based on the detection of the rotational position, the control unit 30 performs switching of the phase of the IGBT 40, and when the normal current supply phase is connected, the motor driving current which drives the motor is increased.

Abstract: At Step Sb3, a duty factor, which was calculated at Step Sb2 on the basis of a data for a feed-back control, is compared with a limit value of the duty factor. If the duty factor is less than the limit value, a pulse for the PWM control is modulated to have the calculated duty factor at Step Sb4. If the duty factor is greater than the limit value, the pulse for the PWM control is modulated to have the duty factor of the limit value at Step Sb5. Accordingly, the duty factor provided for a current value instruction is not in excess of the limit value, so that the secondary battery is prevented from discharging overcurrent in excess of the limit current which can be discharged from the secondary battery. Accordingly, although the capacitance of the secondary battery is not large, the lifetime of the secondary battery is prevented from being shortened.

Abstract: The present invention relates to the positioning of the read/write transducer heads of an hard disk (HD) in a designated landing zone when requested or when the electrical power is removed from the drive. In particularly it relates to the detection of the back electromotive force (BEMF) of the motor involved in the positioning of the read/write transducer heads.

Abstract: In order to identify phase failure in an asynchronous machine, monitoring of the phase currents is performed, a trigger signal being generated for each phase in the event of a limit value being undershot. In order to cover the entire frequency range in converter operation, a changeover is made between different monitoring states. In the first monitoring state, the trigger signal is generated if the instantaneous value of the phase current in each case falls below the limit value. A changeover is then always made to the second monitoring state, where the duration of the trigger signal is compared with the swept angle of rotation of the voltage vector in the same phase. If the state of the phase current lasts during this period of time, in a third monitoring state the duration of the trigger signal or the continuance of the phase current state is checked during a defined delay time interval. If the trigger signal outlasts the delay time interval, phase failure is signaled.

Abstract: A method of reconnecting a motor to a motor drive comprises controlling a current which flows through the motor using a current regulator. The current regulator produces a voltage command output based on a current command input. A current is commanded at the current command input of the current regulator. Back EMF measurements are acquired at different instants in time by monitoring the voltage command output of the current regulator. Back EMF phase angles are determined for a plurality of the instants in time based on a respective plurality of the back EMF measurements. A frequency of the back EMF is determined based on the back EMF angles determined for the plurality of instants in time. The motor drive is reconnected to the motor based on the frequency of the back EMF.

Abstract: An available input of to a motor controller is used to measure the motor power supply voltage. Typically, a scaled down version of the voltage is sensed. The microprocessor is used to calculate the motor control current, in that case, is then calculated from the scaled down version. A scale factor that depends upon the sensitivity of the motor current to the motor supply voltage is calculated by the microprocessor. Driving parameters in the controller are then adjusted to account for the scale factor. In a preferred embodiment, the driving parameters are PWM parameters, and the microprocessor multiplies the measured power supply voltage to obtain a scale factor that can then be multiplied by the nominal PWM values to obtain the new PWM values.

Abstract: A power electrical system is disclosed for a microturbine power generator. The invention permits the microturbine to be started using an external DC power source. The DC voltage is converted to a variable DC voltage by means of a bi-directional buck-boost circuit, DC bus and a DC-to-AC converter. The DC-to-AC converter produces at its output a fixed voltage pattern whose frequency is gradually increased in concert with the DC voltage, to accelerate the microturbine from standstill to startup speed. Once the microturbine is started, the excitation is discontinued, and the DC bus and DC-to-AC are used to produce output AC power at a voltage level and frequency to match an electrical load.

Abstract: Disclosed is a three phase BLDC motor driving circuit which makes a BEMF voltage generated in a motor lower than a voltage source and makes a difference between the BEMF voltage and the voltage source greater than a saturation voltage of a transistor. An emitter is coupled to the voltage source and a collector is coupled to a three phase coil so that the voltage between the emitter and collector of the transistor supplying a current to the three phase coil attenuates to a first level so as not to saturate the transistor.

Abstract: A sensorless control system for an induction motor employs direct tracking of torque and flux regulation to achieve improved motor control without the need for transformation to the rotor flux related frame. A novel torqueflux dynamic model used to implement the control method employs stator voltage as an input, and achieves separation of torque and flux regulation. An alternate regulation method better suited for slow reference signals relies on a steady state solution of the dynamic model.

Abstract: The present invention provides a variable-speed controlling device for use with an induction motor, which includes a means for compensating for the discrepancy between a secondary magnetic flux instruction value and a secondary magnetic flux actually occurring in an induction motor, realizes a satisfactory control by generating the secondary magnetic flux according to the instruction value, and can generate desired torque and improve a motor efficiency. The variable-speed controlling device according to the present invention, for use with an induction motor, includes a voltage instruction value calculating unit, an integrating unit, a power converting circuit, a current detecting unit, an induced voltage calculating unit, a position discrepancy amount calculating unit, and a compensating unit.

Abstract: Motor control of a variable reluctance motor is obtained by providing a periodic voltage waveform to a coil of a motor. No coil current control or current or flux feedback is needed to obtain flux waveforms that allow for low-distortion or distortion-free operation of the motor. The periodic voltage waveform may be a sinusoidal or sawtooth signal, for example, and has a substantially zero mean for each cycle of the signal. The periodic voltage waveform may be offset to compensate for the resistance of the coil, and the coil current may be monitored in order to determine the amount of offset required. By providing a zero-mean or substantially zero-mean periodic voltage waveform, the coil current and flux in the gap between the core and the moving part are guaranteed to reach a zero value at some point during each period (or cycle) of the periodic voltage waveform.

Abstract: A drive system comprises a rotor position and velocity tracker adapted to decouple fundamental frequency effects of a zero sequence signal of an induction machine from the zero sequence signal and to use a resulting error signal to estimate a position and a velocity of a rotor of the induction machine.

Abstract: A method and apparatus for deriving characteristics of a utility signal for synchronizing the output of a motor drive with the utility for a transfer or capture operation. With the drive in idle, the voltage and phase angle of an input to the drive are detected by instrumentation of the drive. The voltage and phase angle of a signal from a utility are detected by instrumentation of the drive at the output of the drive. A phase angle difference and scaling factor are determined to correlate the input signal to the motor drive with the signal at the output of the motor drive. The phase angle difference and scaling factor are stored and subsequently used to derive the signal at the motor due to the utility at the time of the transfer or capture procedure.

Abstract: A speed controller circuit for a motor including a ramp function generator having a first input connected to a source of a speed demand signal and a second input connected to a ramp step signal. The ramp function generator develops a frequency ramp that has a slope is initiated by the speed demand signal which is adjusted in response to the ramp step signal. The ramp function generator also provides a frequency signal wherein the ramp function increases or decreases the frequency according to the speed demand. A V/F circuit to the ramp function generator and a space vector modulation circuit are connected to the V/F circuit. The output of the space vector modulation circuit is applied through power switching devices to the motor for speed control. A PI controller circuit is connected to a motor current feedback signal and to a maximum current signal, which provides the current limit of the control system.

Abstract: A method and device for controlling the torque of a permanent magnet (PM), synchronous, alternating-current (AC) motor, wherein the motor is powered by an inverter connected to a direct-current (DC) power source, is proposed. The method includes the steps of communicating a torque command signal from a user to a microcontroller, sensing the alternating-current phase currents of the motor and communicating electrical signals representing data concerning the phase currents to the microcontroller, sensing the position of the rotor of the motor and communicating electrical signals representing data concerning the position of the rotor to the microcontroller, and utilizing the microcontroller to implement a modulation technique to generate electrical switching signals for creating electrical sinusoidal waveforms.

Abstract: A method for bearing a rotor in which load is shared between a foil bearing part and a magnetic bearing part without using a calculated rotor trajectory corresponding to various rotor spin speeds. Power input to the magnetic bearing part is controlled in response to feedback of rotor position. In order to share the load on the fly so that the load is shared quickly as the rotor speed is changed, the power input is modified in response to rotor spin speed to reduce load capacity of the magnetic bearing part as rotor spin speed is increased and increase load capacity of the magnetic bearing part as rotor spin speed is decreased. Alternative methods of modifying power input include modifying integral gain and inputting rotor spin speed to an adaptive filter to continually reset the adaptive filter at the rotor spin speed. For use of the process with a thrust bearing, the magnetic and foil bearing parts are disposed on opposite sides of the thrust runner.

Abstract: Process for supplying electrical energy to the network with an AC generator associated with a turbine, by means of a transformer, characterized in that it consists in evaluating the generator precisely as a function of the needs of the site by lowering its nominal voltage as low as possible while continuing to satisfy the capacity of the generator to send active power delivered by the turbine and the reactive power corresponding to this active power required by a consumer or the network manager.

Abstract: The present invention relates to a technique for outputting a vibration torque compensating current and removing a torque pulse generated at a footplate by using a detector for detecting a pulse rate generated at a sprocket and a device for detecting the magnitude of a pulse torque of an induction motor without changing the circumferential shape of the sprocket and the connecting structure of the footplate.

Abstract: A moving member 18 of an actuator 10 comprises a moving block 50 wherein an opening 48 which allows a driving force transmission shaft 16 to be inserted from the direction perpendicular to the axis thereof. A controlling device 400 for the actuator controls the amount of current supplied to a rotation drive source 21 on the basis of the manipulated variable control signal outputted though a torque limiter 8 for controlling the torque for the rotation drive source 21 detected by a torque conversion means 10 to the level of a torque limit limit value signal.

Abstract: In the synchronous motor controlling apparatus and method of the invention, a current is detected and subjected to coordinate transformation onto &ggr;-&dgr; axis assumed for the rotor. A correction term is obtained on the basis of the derived current and an arbitrarily given correction current instruction. A &ggr;-&dgr; axis voltage instruction is computed by adding a value obtained by multiplying the correction term by a proper gain to a voltage equation in a steady state of the synchronous motor. Consequently, a control method of small computational load, which does not require gain adjustment according to the inertia of a motor load, can be attained.

Abstract: A method and a control device for braking a variable speed vector controlled induction machine are driven by a pulse width modulation (PWM) inverter, in which the q-current component and the d-current component of the stator current are controlled independently from one another in accordance with a first reference signal (iq*) and a second reference signal (id*), respectively. For braking, high frequency components are superimposed on the second reference signal (id*), and the root-mean-square (rms) value (id rms) and the average value (id av) of the resultant second reference signal are controlled independently from one another such that the field requirements are met by the average value and high machine losses are produced by the rms value.

Abstract: A method of regulating a rotary machine powered by a voltage inverter receiving, as input a control voltage delivered by a regulator servo-controlling the electromagnetic torque on a reference value, the regulator receiving as inputs the reference value and sat least one sampled signal representative of the torque of the machine, and proceeding at each sampling instant, to predict the torque value at a following sampling instant and to modify the control voltage accordingly.

Abstract: A three-phase motor having three Hall-effect devices for production of as many rotor position signals for use in excitation control of its windings, the signals being indicative of the angular position of the motor rotor with respect to the stator and having phase differences of 120 degrees. A motor speed control system is disclosed which utilizes the rotor position signals for detection of the actual running speed of the motor. Included are differentiating circuits connected one to each Hall-effect device for producing outputs in prescribed phase relationship with the rotor position signals. Connected to the differentiating circuits, switching transistors are controlled by binary switch control signals derived from the rotor position signals, passing the positive half-waves, or approximately positive half-waves, of the differentiating circuit outputs. The thus-obtained half-waves are then added together into a motor speed signal representative of the actual running speed of the motor.

Abstract: A drive circuit for a speed adjustable fan comprises a computing IC, a Hall IC, an input terminal for external signals, and a current control circuit. The drive circuit is arranged inside the fan to control the speed of the fan without the need of an external circuit. The computing IC is connected to a Hall IC and controls two transistors connecting therewith in a state of connecting and in a state of disconnecting sequentially such that two coils of the fan are alternately magnetized so as to rotate the fan. The input terminal for external signals detects the current of the external signal source and the current is regulated by the current control circuit in the process of passing through the coils to adjust the speed of the fan.

Abstract: A system for controlling the speed of an induction motor by controlling an output voltage and an output frequency of a power inverter in accordance with a speed command includes a computing unit 10 for determining a slip-frequency computed value &ohgr;s2; an adder 11 for outputting a slip-frequency estimated value &ohgr;s{circumflex over ( )}; an adder 12 for adding &ohgr;s{circumflex over ( )} to a speed command value &ohgr;r* and outputting &ohgr;1*; a d-axis current commanding unit 14 for outputting a d-axis current command value id* which is a value greater than a normal value; an amplifier 15 for outputting a voltage command value ed*; a gain commanding unit 16 for commanding a gain Gd; a q-axis current limiter 17 for controlling a q-axis current iq substantially to zero in a zero speed range; and a gain commanding unit 18 for commanding a gain Gq.

Abstract: A method for commutation of a switched reluctance motor (SRM) is disclosed that requires no rotor position sensor or detailed prior knowledge of the motor's magnetic characteristics. The apparatus and method employs a calibration routine to learn the flux-current characteristics of each SRM phase in its aligned position. From these characteristics, the flux-current characteristics at other appropriate switching angles are approximated. Commutation is accomplished by estimating the flux in an active phase and comparing the estimate to the flux approximated for the switching angle. The apparatus and method is particularly well suited for relatively heavy duty loading applications, such as a fan.

Abstract: In an induction motor drive system with/without a speed sensor, resistance values are stably and accurately estimated during the operation of the motor regardless of the operating conditions such as a speed, a load, etc. and of a particular combination of parameters. A suitable point Pr is taken inside a current locus on a stator current vector plane, and a measured current is and an observed current is′ are referenced from this point Pr. The difference between the magnitudes of two vectors is and is′ is associated with an error of a rotor resistance Rr, while the difference between phase shifts is associated with an error of a stator resistance Rs.

Abstract: A magnetic tape recording/playback apparatus, and a method of operating the apparatus, which minimises or eliminates the tape damage which is caused by the tape-driving capstan spinning and skidding across the tape at start-up. Initial acceleration of the capstan is held to a relatively low level when capstan speed is below a predetermined value and capstan acceleration is at a higher level at capstan speeds above said predetermined value. Intermediate levels of capstan acceleration can be set for intermediate speeds.

Abstract: A diagnostic system for electric motors, such as those used in automotive applications. The system comprises a controller for supplying a desired command current to said electric motor, a sensor for measuring the rotational speed of the motor, a sensor for measuring the actual current supplied to the motor by the controller, a diagnostic control unit adapted to receive the measured rotational speed, measured supplied voltage, and a command current level value as inputs. The diagnostic control unit further comprises circuitry to calculate an estimated actual current drawn by the motor and to signal an error condition if the estimated actual current is not within a calculated valid range.

Abstract: An electronic cam servo apparatus uses a digital servo controller to perform motion equivalent to a mechanical cam. The control apparatus has one data table representing a characteristic of a mechanical cam and utilizes a data interpolation and the first derivative of a cam position profile to determine position and velocity commands to drive a servo motor which performs motion equivalent to a mechanical cam. Alternatively, the control apparatus uses the first cam specific data table to determine the position, velocity and torque/current command to drive a servo motor. The apparatus may additionally use a second data table representing varying cam load to obtain a more accurate torque/current command correction.

Abstract: The present invention addresses a problem as to how to provide a motor control apparatus which has a magnetic pole position inferring means capable of inferring the position of a magnetic pole of a synchronous motor by adopting a simple method in a short period of time with a high degree of accuracy. In order to solve this problem, a signal id1* for inference use is applied and a peak value iqh of a response current iq′ is detected by an iq′ peak detecting unit. The peak value iqh is then supplied to a magnetic pole position inferring unit for inferring the position of the magnetic pole of the synchronous motor by carrying out multiplication processing.

Abstract: In a brushless motor driving circuit of the invention, in the starting operation, an applying voltage is low and also the induced voltage is low, so that output values from sample and hold circuits 6 and 7 are substantially equal to each other. Thus, an output from a comparing circuit 10 is substantially equal to an output of a V/f converting circuit 11. As a result, the starting method which is identical with a conventional method is used. By contrast, when the number of rotation of a brushless motor 1 is increased, and the induced voltage is started to be observed, the condition is spontaneously shifted to that in which the driving voltage is automatically controlled at each time to an appropriate value for the number of rotation and the load of the motor. Accordingly, the switching operation from the starting control to the normal control is not required.

Abstract: A control system for an electric lift truck that controls a traction motor and a hydraulic pump motor is disclosed. The speed of rotation of both motors is controlled by a pulse width modulated current supplied from a battery source by the controller in direct response to a demand communicated to the controller through an interface manipulated by an operator. A pump driven by the pump motor supplies pressurized hydraulic fluid to a lift mechanism and a power assisted steering unit. A joystick with function switches mounted thereto is provided so that the operator steers with one hand while controlling truck propulsion and all functions of the lift mechanism with the other hand. The direct control of the pump motor speed enables a fully proportional control of the hydraulic system. The control system is a compact structure that requires minimal cabling and ensures that the hydraulic system operates with energy efficiency and minimal wear.

Abstract: A motor control unit (1) includes a white noise generator (8), an instruction switch (9) for switching between an input control instruction (Vins) and a white noise output of the white noise generator (8), a controller (10) for feedback controlling the motor drive velocity, a detection unit (13) for detecting and sampling the real velocity of a motor or a load at a predetermined period, a first Fourier transformer (15) for Fourier-transforming the control instruction data (Cins) together with the sampled velocity data (Vm), and a first frequency characteristic operation unit (16) for calculating the frequency characteristics in a range from the velocity instruction (Cins) to the sampled velocity (Vm) based on output data of the first Fourier transformer (15), thus obtaining the frequency characteristics in a short period without necessity of a servo-analyzer.

Abstract: A system for controlling a brushless dc motor includes a motor driver circuit that outputs a drive current to the motor and a power supply that provides power to the motor driver circuit. Feedback circuits provide signals indicative of: a speed of rotation of the motor and at least one of: a level of the supply voltage provided by the power supply, and the output current from the motor driver circuit. A processor analyzes the feedback signals and determines if a required change in drive current to the motor will result in a saturation or near saturation condition. If such a saturation or near saturation condition is anticipated, the processor initially determines if a change in commutation angle will avoid the saturation or near saturation condition and if yes, outputs a control signal to alter the commutation angle.