A fluctuating oscillator includes: a processor including a digital circuit, and the processor includes a random variable generation unit that generates a random variable, a lookup table that stores a waveform signal in advance, a computation unit that imparts fluctuation to the waveform signal based on the waveform signal read from the lookup table, the random variable generated by the random variable generation unit, and a pulse signal to be fed back, a threshold discrimination unit that generates a pulse signal by comparing a fluctuating signal output from the computation unit with a predetermined threshold, and a feedback loop that causes the pulse signal to be fed back to the computation unit.

An electric tool system includes a motor, a control unit, and an output shaft. The motor includes a stator and a rotor. The control unit performs vector control on the motor. The control unit includes a first acquisition unit, a second acquisition unit, and a command value generation unit. The command value generation unit calculates, based on a torque current acquisition value (current measured value) as a value related to a torque current as acquired by the first acquisition unit and an acceleration acquisition value as a value related to acceleration of the rotor as acquired by the second acquisition unit, at least one of a command value of the torque current to be supplied to the motor or a command value of an excitation current to be supplied to the motor.

A motor drive device includes: a position command generator which generates a position command; a damping filter unit which includes one or more stages of damping filters which reduce vibration of a device including a load and a motor, applies, to a position command, a damping filter determined based on a model parameter corresponding to a model of the device, and outputs a filtered position command to which the damping filter has been applied; a servo controller which gives a torque command to the motor based on the filtered position command; a low-pass filter unit; a parameter estimation unit which estimates the model parameter from the rotational speed and the torque command of the motor which have passed through the low-pass filter unit; and a vibration determination unit which determines presence or absence of vibration in the model.

A field of electric drive devices and electric machines, such as electric motors and electric generators for industrial applications and more particularly to a method and an arrangement for controlling vibration of a variable frequency drive controlled electric machine. In the method for controlling vibration of a variable frequency drive controlled electric machine, the resonance frequency/frequencies and the stiffness are determined in a ramp up/ramp down test; amount of damping is determined in an impulse test; a mechanical transfer function is determined in a steady drive test; a vibration control model is determined utilizing said resonance frequency/frequencies, said stiffness, the amount of damping and the mechanical transfer function; and vibration is controlled utilizing the vibration control model.

A variety of methods, controllers and electric machine systems are described that facilitate pulsed control of electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and a second output level that is lower than the first output level. The output levels are selected such that at least one of the electric machine and a system that includes the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the second output level is zero torque.

A non-sensor type closed-loop stabilization control algorithm comprises the following steps: 1, reading all voltages V.sub.k−1 and currents I.sub.k−1 for driving a multi-axis stabilization motor; 2, calculating and outputting all coil resistances R.sub.k−1 in the multi-axis stabilization motor; 3, reading all the coil resistances, voltages and currents in the steps 1 and 2, and calculating and outputting counter electromotive force E.sub.k−1 of all the coils in the multi-axis stabilization motor; 4, reading an stabilization compensation angle θ.sub.k, each coil resistance and the counter electromotive force, and calculating and outputting a closed-loop stabilization control F.sub.k; and 5, then waiting for a time step k=k+1, and repeating the steps in the steps 1 to 4. It aims to add a closed-loop control element to a motor without a sensor to achieve an excellent stabilization effect and to reduce the risk of image blurring caused by resonance.

A blower motor control device stops energization to a motor when a rotation speed of a rotor reaches a learn rotation speed, and acquires a correction amount as a new learn value for correcting a position error of the rotor relative to a Hall element by using an induced voltage in a coil of the motor and a detection signal from a rotation sensor. The blower motor control device stores the new learn value in a ROM. The blower motor control device corrects the position error by using a previous learn value read from the ROM, for energization control of the motor, until the rotation speed reaches the learn rotation speed.

A motor drive control device includes: a feedback control unit calculating an operation amount (Sad) of a motor such that a rotation speed S3 of the motor matches a target rotation speed S1; a drive control signal generation unit generating a drive control signal Sd based on the operation amount Sad; a current fluctuation detection unit detecting a fluctuation of a current flowing through the motor; a correction instruction unit instructing correction of the operation amount Sad when the fluctuation of the current flowing through the motor is detected by the current fluctuation detection unit; and a correction unit correcting the operation amount Sad and providing the corrected operation amount S2 to the drive control signal generation unit when the correction of the operation amount Sad is instructed from the correction instruction unit.

A chiller system includes a compressor, a condenser and an evaporator in fluid communication. A motor drives the compressor. A variable speed drive powers the motor. An oil heater and pump system circulate heated lubricating oil in the compressor. A control panel is arranged to determine whether an input parameter is greater than or equal to a threshold parameter; deactivate the VSD in response to sensing that the input parameter is less than the threshold parameter; determine at least one chiller capacity control parameter at a point when the VSD is deactivated, and maintain the at least one chiller capacity control parameter while the VSD is deactivated; determine that the input parameter has been restored; determine a motor rotation and motor rotational speed; and in response to determining that the input parameter is restored and the motor is rotating in a forward direction, reactivate the VSD.

A variety of methods, controllers and electric machine systems are described that facilitate pulsed control of electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and a second output level that is lower than the first output level. The output levels are selected such that at least one of the electric machine and a system that includes the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the second output level is zero torque.