347results about "AC motor accelaration/decelaration control" patented technology

A power control structure aims for an electric power tool which gets an input power from an electric power source and converts the input power to a driving power to drive an electric motor. The electric power tool further includes a manual control means, a magnetic control element and a power modulation circuit. The manual control means includes a trigger portion movable by depressing of a user and a magnetic element movable with the trigger portion. The magnetic control element outputs an output control signal in proportion to alterations of a magnetic field caused by movements of the magnetic element. The power modulation circuit gets the input power and modulates to the driving power controlled by the output control signal to drive the electric motor. Thus by depressing the trigger portion, output power of the electric motor can be controlled to provide precise control of rotational speed and torque alterations.

A stepping motor is driven in both closed-loop and open-loop modes while initiating microstepping after a predetermined threshold velocity has been reached. A feedback device such as an encoder is mounted on the stepping motor shaft and the encoder keeps track of the mechanical position of the rotor. Based on feedback from the encoder, stator phases are activated to maintain a 90° phase advance and produce maximum torque. A lead angle compensation technique is used to advance the motor lead angle, to allow for the excitation currents to reach maximum even at higher speeds. The stepping motor controller employs this strategy in order to produce maximum torque across a wide range of motor speeds and actuator motions.

A control for an electric motor is utilized to avoid operation in or near the resonance frequencies for the electric motor and its associated system components. The resonance frequencies can be identified experimentally at the design stage, or during operation of a component and electric motor. During start-up, shutdown or frequency adjustment, the control drives the speed through the resonance frequency zones more rapidly, and also avoids operation in or near those resonance frequencies during steady state operation. In disclosed embodiments, the electric motors are associated with fans, pumps and compressors in a refrigerant system.

A fitness equipment energy regenerating and saving system is provided. The system includes a bidirectional power converter, a bidirectional power drive, a generator, and an energy managing circuit. The energy managing circuit activates the bidirectional power converter so as to enable the bidirectional power drive to feedback the power generated by the generator to an electrical grid when the generator is operated in a generator mode. The energy managing circuit sets the bidirectional power converter to a current-regulating mode so as to enable the bidirectional power drive to obtain the power required for driving from the electrical grid when the generator is operated in a motor mode.

AC motor control systems and speed controllers are presented, including a transient-based speed estimation system that provides a rotor speed estimate based on a measured speed-related motor transient signal, and a transient excitation system which selectively modifies at least one switch control signal to excite the measured motor transient. The measured speed-related transient may include a phase error signal, a phase lag signal, a peak current signal, a voltage integral signal, a motor winding voltage signal, a switching device voltage, and a voltage zero crossing signal, and the switching signal modification can comprise removal of select pulse(s) from a switching control pulse stream or selective modification of spacings between pulses to re-excite the motor transient.

An apparatus to deliver air to a patient through a mask, including an air blower (33) where the impeller (5) is rotated by an electromotor including a rotor (3) and a stator (8), the stator having at least three sectors (8a, 8b and 8c), the rotation of the rotor being enabled by changes of the polarity of the sectors, each sector's polarity configuration constituting one step of the rotor's rotation, the apparatus including a driving unit (36) changing the sectors' polarity when the rotor is at its optimal position, so that the efficiency of the electromotor enables the blower to have fast accelerations and decelerations within one patient's breath step, the breath step consisting of one inspiration and one expiration.

When motor drive is initiated, firstly a PWM value at time of driving initiation is set to an initial setting value start_pwm1, and gradually increased by a specified amount in specified period. When an encoder edge is detected, the PWM value is reset to the initial setting value, and increased again in the same manner. From second edge detection, next PWM initial value is set corresponding to a PWM value at the time of edge detection. If the PWM value at the time of edge detection is larger than det_pwm_max owing to load on the motor becoming large and thereby driving velocity becoming slower, a PWM value which is larger than previous PWM initial value is set as a new PWM initial value. The driving target can be driven stably irrelevant to fluctuation of the load on the motor.

A controller that performs pulse width modulation control of a three-phase inverter circuit includes a three-phase modulation voltage command value generation unit, a two-phase modulation voltage command value generation unit, a voltage command switching unit, and a PWM signal output unit. The voltage command switching unit switches a voltage command value to a two-phase modulation voltage command value when a determination value becomes larger than or equal to a first threshold value, and switches the voltage command value to a three-phase modulation voltage command value when the determination value becomes smaller than a second threshold value, which is smaller than the first threshold value.

In a control unit for a robot, an inverter which drives a motor installed in a robot. A control circuit controls drive of the motor. A drive power circuit supplies DC power to the motor, and a control power circuit DC power to the control circuit. A backup power circuit supplies backup DC power to the control circuit when the DC power from the control power circuit to the control circuit is shut down. A first switch is arranged between the backup power circuit and the inverter, the first switch being selectively switched on and off to open and close. A first switch control section switches on the first switch such that the DC power in the backup power circuit is supplementarily supplied to the inverter when the motor is driven to be accelerated.

A command value generating circuit (7) determines an acceleration profile (A(t)) representing temporal changes in acceleration of a mechanical load (3) in such a manner that: the mechanical load (3) accelerates from a standstill at a first position to a peak velocity (Vp), and decelerates from the peak velocity (Vp) and is brought to a standstill at a second position; the absolute value of the acceleration when the mechanical load (3) is accelerating and decelerating is less than or equal to a prescribed maximum acceleration (Amax); and the prescribed maximum acceleration (Amax) is maintained over a prescribed time from the start of acceleration of the mechanical load (3), and then gradually decreases from the maximum acceleration (Amax). The command value generating circuit (7) determines a velocity profile representing temporal changes in velocity of the mechanical load in accordance with the acceleration profile (A(t)), and generates a position command value (24) in accordance with the velocity profile.

An AC motor can be decelerated in as a short time as possible by means of an inverter and the current is controlled below a predetermined value so that the inverter does not stop because of an overcurrent or the AC motor does not fail due to burnout even if the AC motor is liable to be magnetically saturated. A method and device for driving an AC motor by means of a voltage inverter having therein a voltage correcting section for correcting a given voltage command by using the value obtained by passing a DC bus voltage detected value through a primary delay filter. The AC motor is decelerated in an overexcited state by increasing the time constant of the primary delay filter above the time constant in the normal control state. The current flowing through the AC motor is monitored and the time constant is adjusted according to the current flowing through the AC motor. Therefore, the AC motor is decelerated without causing a failure and the deceleration time can be shortened.

A method is proposed for braking a synchronous machine 1, with the armature windings (u, v, w) of the synchronous machine 1 being short-circuited, optionally by interposing at least one braking resistor. In order to keep the braking moment constant over virtually the entire speed range it is proposed that the short-circuit current is regulated by a pulse-width modulation depending on the difference between the setpoint value of the short-circuit current corresponding to the setpoint value of the braking moment and the actual value of the short-circuit current.

A control device (30) generates, upon receiving an instruction to start engine (ENG) while drive wheels of a hybrid vehicle are driven by a motor generator (MG2), a signal (PWMC) to output the signal to a voltage step-up converter (12), and thereby drives and controls the voltage step-up converter (12) to step up a DC voltage (Vb) that is output from a battery (B) to a maximum voltage (Vmax) of a motor drive apparatus (100). Then, the control device (30) generates, when an output voltage (Vm) of the voltage step-up converter (12) reaches the maximum voltage (Vmax), a signal (PWMI1) to output the generated signal to an inverter (14). Accordingly, the inverter (14) is driven and controlled to drive motor generator (MG1) in powering mode.

The invention discloses a high-precision valve control method. The method comprises the following steps of 1, setting system parameters; 2, judging a current valve location value of a valve; 3, according to a target valve location value, calculating a motion stroke at this time; 4, judging the motion stroke at this time; 5, planning a speed curve, wherein according to the motion stroke at this time, the speed curve is planned, and is divided into an acceleration phase, a uniform speed phage and a deceleration phase; 6, controlling the rotational speed according to the speed curve planed in step 5. By means of the high-precision valve control method, the motion control precision of an executor is improved, the running speed can be flexibly adjusted, mechanical shock brought in running is lowered, the material wearing condition of a transmission structure is improved, and the service life of products is prolonged.

The invention relates to an automatic gear shifting control system of a motor in an electric automobile, which is characterized by comprising the following components: a motor controller, a system controller, a battery voltage sensor, a battery current sensor, a first rotating speed coder, a second rotating speed coder, a folk position sensor group, a transmission motor oil temperature sensor, and a pressure source pressure sensor; wherein, the input ends of the motor controller are connected with two output terminals of a storage battery via a first wire; the output end of the motor controller is connected with the input end of the power supply via a second power supply wire. By using the invention, response is rapid, and gear shifting time is less than 1s; speed control is controller at constant speed with accuracy, and the phase error is less than 1 degree; gear shifting is smooth without any gear shocking.

An object of the present invention is to provide a driver for an induction motor which performs an operation at an acceleration suitable for the magnitude of a load and is excellent in efficiency, without an acceleration failure.

The driver for an induction motor includes a slip frequency estimate value arithmetic operation section 15 for arithmetically operating a slip frequency ωŝ of an induction motor 12, and a maximum torque generation slip arithmetic operation section 16 for arithmetically operating a slip frequency ωsmax at which a maximum torque is generated. When the slip frequency ωŝ exceeds a predetermined value ωsmaxTH(=0.96ωsmax, etc.) corresponding to the slip frequency ωsmax at which the maximum torque is generated, a speed change rate arithmetic operation section 17 and a speed change rate correcting section 18 reduce a rate of increase in a speed command ωr*.

In addition, when the slip frequency approaches the maximum torque generation slip frequency too closely, the load concerned is judged to be overloaded, and an alarm is generated.

A driving method of an induction motor, in which a driving device for an induction motor that drives a polyphase induction motor to rotate by outputting an AC voltage of an output frequency determined according to an operating speed from a variable voltage and variable frequency conversion device executes the first step 1st step and 2nd step, wherein, in the 1st step, during steady operation, the output frequency is set from the 1st frequency setting value to the 2nd frequency setting higher than the 1st frequency setting value When the value is switched and the induction motor is accelerated, the conversion device, when increasing the output frequency to the second frequency setting value, increases the output voltage to an overvoltage state output compared with the usual one; in the second step , and then maintain the output frequency at a value corresponding to the second frequency setting value and return the output voltage to a normal state. Accordingly, when the induction motor that has already been started and is in a stable operating state is accelerated from the current rotational speed to a higher rotational speed than this, the time required for acceleration can be shortened.

A control method includes monitoring changes in torque produced by a traction motor when an excitation frequency of current supplied to the traction motor changes, determining if the torque produced by the traction motor decreases when the excitation frequency of the current supplied to the traction motor increases, and responsive to the torque produced by the traction motor decreasing when the excitation frequency increases, preventing the excitation frequency of the current supplied to the traction motor from increasing further.

A system and method for controlling an adjustable speed drive (ASD) to decelerate an AC load during a generating mode of operation is disclosed. The ASD includes a capacitor and an inverter coupled to a DC link. A current sensor system is coupled to an output of the inverter. The ASD further includes a control system programmed to calculate an energy of the capacitor, generate a reference power using the calculated capacitor energy, and calculate a feedback power from realtime current signals received from the current sensor system. The control system compares the feedback power to the reference power, defines a frequency offset based on the comparison, generates a speed command using the frequency offset, and outputs the speed command to the inverter to maintain a smooth DC link voltage during deceleration.

The invention discloses a motor control method, which comprises the following steps: in an acceleration time interval, increasing the rotation speed of the motor to the maximum rotation speed value according to a first speed curve; in a constant speed time interval, keeping the rotation speed at the maximum rotation speed value; and in a reduction time interval, reducing the rotation speed to zero according to a second speed curve. The coincidence of the corresponding time points of the first speed curve and the second speed curve is associated with the maximum rotation speed value. The method further allows a user to set the time point of the change of the acceleration flexibly without influencing the smoothness of the operation of the motor and mechanisms connected with the motor.

A motor drive having controller settings which will result in improved tuning-less performance is disclosed. Gain values for the control loops and/or observer are determined independently of the mechanical loading and the resultant effects of that loading on the motor. The motor drive includes a control loop operable to receive a command signal and to generate a controller reference signal to achieve desired operation of a motor connected to the motor drive. The motor drive also includes a load observer operable to generate a signal that estimates a response required by the motor drive as a result of a load present on the motor. The response estimate signal is provided to the controller to isolate the effects of the load dynamics from operation of the control loops within the controller. A modified controller reference signal is generated as a function of the response estimate signal and the controller reference signal.