2014results about "Torque ripple control" patented technology

Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage of the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage. The speed control signal is provided as feedback to control an amplitude of the drive voltage. In one embodiment, an apparatus includes a brushless DC motor and a commutation control. The commutation control provides a commutation control signal for a selected phase of the motor in accordance with a sampled back electromotive force (emf) of that phase. The back emf of the phase is sampled only while the corresponding drive voltage for the selected phase is substantially zero, wherein a frequency of a drive voltage of the motor is varied in accordance with the commutation control signal.

A low-cost sine-wave drive for a 3-phase permanent magnet synchronous AC machines (PMSM) in open-loop control is based on the measurements of two linear Hall sensors. The two Hall sensors are excited by a magnetic ring with the same pole number as the PMSM rotor magnet and sinusoidal flux distributions. The output signals of the Hall sensors are unified through a two-phase-type phase-lock-loop in order to reduce the impact of the sensor mounting non-uniformity during mass production. The peak torque and speed of motor is simply controlled by adjusting the amplitude of pulse-width-modulation carrier. Smooth torque control is achieved due to sinusoidal 3-phase currents. Such a simple sine-wave drive can be achieved with or without the assistance of a micro-controller unit (MCU). No current sensor is required for the motor phase current detection. This motor can be used in industrial applications where there is no strict requirement on torque response and constant speed control of PMSM machines.

In an operation range of an actuator subjected to quick acceleration and deceleration, a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area. A controller comprises a voltage saturation detecting means for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

Methods and apparatus are provided for reducing torque ripple in a permanent magnet motor system comprising a permanent magnet motor coupled to an inverter. The method comprises the steps of receiving a torque command, generating a torque ripple reduction signal in response to the torque command, modifying operational control signals in response to the torque ripple reduction signal to generate reduced ripple operational control signals, and providing the reduced ripple operational control signals to the inverter for control of the permanent magnet motor.

A position sensor-free double closed-loop speed regulation control method for a brushless DC motor comprises the following steps: (1) initializing functional modules and peripherals; (2) opening AD (Analog-Digital) interruption and protection interruption; (3) detecting the start key of the motor, judging whether to start the motor, if yes, executing the next step, and if not, continuing to execute the step; (4) starting voltage detection, judging whether the voltage of a main circuit is larger than starting voltage, if yes, executing the next step, and if not, returning to the step (3); (5) entering a motor starting subprogram and beginning operating the motor; (6) entering a double closed-loop speed regulation subprogram, and regulating the rotational speed and the current of the motor according to voltage value; and (7) detecting a motor brake key, judging whether to press the key, if yes, entering a motor brake subprogram, and if not, returning to the step (3). The method provided by the invention overcomes the defects of larger size, low rotational speed accuracy and the like of the conventional motor controller, can accurately control different rotational speeds of the motor, and can simultaneously realize counter electromotive force zero-cross comparison position sensor-free reversing and Hall position signal reversing.

A system for controlling torque ripple in a permanent magnet synchronous machine includes a power converter configured to be coupled to the permanent magnet synchronous machine and to receive converter control signals and a system controller coupled to the power converter. The system controller includes a fundamental current controller configured for providing fundamental voltage commands, a harmonic current controller configured for using harmonic current commands, current feedback signals from the permanent magnet machine, and fundamental current commands in combination with positive and negative sequence regulators to obtain harmonic voltage commands, and summation elements configured for adding the fundamental voltage commands and the harmonic voltage commands to obtain the converter control signals.

This invention relates to detecting, analyzing method and devices of permanent magnetic field deformation in permasyn motor. It is in the electric machine control technique field. This method is based on signals which are easy to detect such as voltage, current, electric engine rotate speed, location of the rotor, and so on. To get a real-time observation to the changing state of permasyn motor permanent magnetic field and calculate the back electromotive force coefficient, the permanent magnetic flux linkage on magnetic field synchronous revolution dq coordinate system of permasyn motor. Then the harmonic component in permanent magnetic waveform reflected motor phase winding back electromotive force coefficient by analyzing the back electromotive force. According as those methods, the optimizing control can be applied to forecast and prevent status of excitation losing in permasyn motor. The outcome has already reached can apply to excitation losing online detecting and high performance control of electric engines.

A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

A temperature estimation module estimates a change in temperature of the magnets associated with the rotor of the motor based on an operational magnetic flux strength that is compared to a reference magnetic flux strength determined at a known ambient temperature and for a predetermined operating range of the motor The temperature estimation module or the system establishes a relationship between the estimated change in the temperature and a magnetic torque component of a target output torque of the motor consistent with the predetermined operating range. The current adjustment module or the system adjusts a command (e.g., quadrature-axis current command) for the motor to compensate for shaft torque variation associated with the estimated change in the temperature in conformance with the established relationship.

An electric power steering apparatus includes: a rotation speed detecting unit which detects a rotation speed of the electric motor; a compensation current determining unit which determines an instruction value of a compensation current to flow through the electric motor to suppress torque ripples due to distortion of an induced electromotive force waveform of the electric motor in accordance with a load correspondence quantity as a physical quantity corresponding to a load of the electric motor and the rotation speed detected by the rotation speed detecting unit; a correcting unit which corrects the current target value on the basis of the compensation current instruction value; and a control unit which performs a feedback control on the electric motor so that a current having the current target value as corrected by the correcting unit flows through the electric motor.

Systems and methods are disclosed to improve torque linearity of an electric machine when operating in a field-weakening region. The systems and methods adjust the q-axis and the d-axis components of the stator current commands of the electric machine using a flux weakening control loop and a torque linearity control loop such that torque linearity is maintained when the machine operates in a field weakening region of operation.

The invention discloses a direct torque control device and a direct torque control method for a permanent magnet synchronous motor. The DC bus voltage of an inverter and a current signal of the permanent magnet synchronous motor are output to a signal detection circuit; the signal detection circuit outputs the DC bus voltage and the current signal to a processor; meanwhile, a rotating speed pulse signal of the permanent magnet synchronous motor is output to the processor and is processed by the processor to form a proper switch signal which is then output to the inverter so as to control the motor. A proper voltage vector is selected from twelve synthesized voltage vectors according to a flux linkage error and a torque error and the position of the flux linkage in twelve sectors, and the duty ratio of the selected voltage vector is determined in real time according to the torque error so as to generate a proper inverter switch signal for controlling the permanent magnet synchronous motor. The number of the selectable voltage vectors in the traditional direct torque control is increased, the duty ratio of an acting vector is adjusted in real time according to the torque error, and the torque pulsation in the traditional direct torque control can be effectively reduced.

A method and system for operating an automotive electric motor having first and second components is provided. A desired frequency of vibration for the electric motor is selected. A current is caused to flow through at least one of the first and second components such that the second component moves relative to the first component. The current is modulated such that the motor vibrates at the desired frequency.

A synchronous AC motor has a stator with stator poles arranged as a plurality of circumferentially extending stator pole groups, with each stator pole group having a pair of corresponding circumferentially extending loop-configuration stator windings disposed adjacent on either side or a single such winding disposed adjacent at one side, adjacent stator pole groups being mutually circumferentially displaced by a fixed amount corresponding to a specific electrical phase angle. A rotating magnetic field is produced by applying respective polyphase AC voltages to the windings, such that currents of mutually opposite direction flow in each pair.

A method of controlling an electric machine that includes sequentially exciting and freewheeling a winding of the electric machine. The winding is excited in advance of zero-crossings of back emf in the winding by an advance angle, and the winding is freewheeled over a freewheel angle. The method then includes varying the advance angle and the freewheel angle in response to changes in the speed of the electric machine. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine.

Methods and systems are provided for reducing torque ripple in an electric motor. A method comprises receiving a torque command and determining a cancellation current command based on the torque command. The method further comprises generating a harmonic cancellation command based on the cancellation current command, wherein the harmonic cancellation command compensates for a phase shift and an attenuation introduced by a current regulated control module coupled to an inverter coupled to the electric motor. The method further comprises providing the harmonic cancellation command to the current regulated control module, wherein the current regulated control module is configured to control the inverter in response to the harmonic cancellation command and the torque command.

The invention discloses a permanent magnet biased bearingless switched reluctance motor, which comprises stator back yokes, permanent magnets, stator suspension cores, stator torque cores, magnetic shields, suspension winding coils, torque winding coils, rotor cores and a shaft, wherein the stator suspension cores are wound with the suspension winding coils; the stator back yokes are arranged outside the stator suspension cores and connected with the stator suspension cores; the permanent magnets are arranged between the two stator back yokes; the magnetic shields and the stator torque cores are arranged in stator suspension core slots; the magnetic shields are positioned between the suspension stator windings and the stator torque cores; the rotor cores are arranged in the stator suspension cores and the stator torque cores; gas are reserved between the rotor cores and each of the stator suspension cores and the stator torque cores to form air gaps; and the shaft is arranged in the rotor cores. By the permanent magnet biased bearingless switched reluctance motor, decoupling control over torque and suspending power is realized to bring convenience to high-speed running; and a suspension biased magnetic flux is provided by the permanent magnets to reduce suspension power consumption and improve the efficiency of the motor.

The present invention relates to an anti-jerk control apparatus and method for an Hybrid Electric Vehicle (HEV).

The anti-jerk control apparatus includes a model speed calculation unit for calculating a model speed of the motor in a state in which a vibration of a drive shaft is not considered. A vibration occurrence determination unit detects a speed vibration component while calculating a reference speed difference and an average speed difference from differences between the model speed and an actual speed of the motor, thus determining whether a vibration occurs on the drive shaft. A torque correction value calculation unit calculates a motor torque correction value for anti-jerk required to damp the vibration of the drive shaft, and controls torque of the motor if the vibration occurrence determination unit determines that the vibration occurs on the drive shaft.

An electrical control system having a direct current to direct current regulator receiving a direct current supply input, wherein the regulator outputs a controlled voltage direct current inverter power feed. Included is an inverter in electrical communication with the regulator and receives the controlled voltage direct current inverter power feed, the inverter outputs an alternating current motor power feed to a permanent magnet brushless direct current motor that outputs a shaft rotational speed and a back electromotive force. Also, a control is provided for regulating the controlled voltage direct current inverter power feed based upon criteria utilizing the back electromotive force or an auxiliary motor stator wire loop signal in conjunction with an optional voltage look-up table to substantially make the controlled voltage result in a reduction of a pulse width modulation switching frequency to further smooth and reduce harmonic of the alternating current waveform to increase motor efficiency.

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.