Abstract: An initial position determination process and a rotation driving process are both attained. A motor includes a rotor having a permanent magnet with a plurality of magnetic poles and a stator having coils with a plurality of phases. A voltage signal generation part generates a voltage signal corresponding to an electric current flowing through each of the coils with the phases of the stator. A filter part includes a first filter and a second filter. The voltage signal is inputted to a comparator through the filter part. A control part controls such that the first filter whose filter constant is larger is selected when performing the initial position determination process of the rotor and the second filter whose filter constant is smaller is selected when performing the rotation driving process.

Abstract: An electric machine includes an alternating current electric motor comprising two semi-windings and an inverter comprising at least two inverter branches which are electrically connected each one to a respective semi-winding. The machine also includes a control unit which provides respective control signals to the two inverter branches so that they induce two alternating currents of frequency in the respective semi-windings. The control signals of the two inverter branches have a frequency smaller than the frequency and are also reciprocally out of phase by 180° relative to the frequency. This allows reducing ripples of the overall alternating current resulting from the sum of the two alternating currents provided by the two semi-windings.

Abstract: Output voltage feedback systems and methods are provided for controlling voltage source inverter output voltages using low bandwidth buffer circuitry and low A/D converter sample rates to sense and sample PWM output voltage waveforms to provide an estimated volt-second value for phase voltage or line-line voltage as feedback for controlling the voltage source inverter.

Abstract: The machine in accordance with the present disclosure is an AC machine whose pole numbers can be switched (from pole p1 to pole p2), and whose number of series turns per phase N can be switched say from N0=Nrated to N1=N0/2. Furthermore, it employs an inverter so that the frequency can be changed from a low value (e.g., 5 Hz) to a high value (e.g., 200 Hz). Due to the combination of pole number and number of series turns switching/reconfiguration, a high torque at low speed (e.g., 0 rpm) and a high torque at high speed (e.g., 5,000 rpm) can be achieved, making mechanical gears obsolete. In addition, the output power of the motor can be increased at high speed in direct proportion to the speed increase.

Abstract: The machine in accordance with the present disclosure is an AC machine whose pole numbers can be switched (from pole p1 to pole p2), and whose number of series turns per phase N can be switched say from N0=Nrated to N1=N0/2. Furthermore, it employs an inverter so that the frequency can be changed from a low value (e.g., 5 Hz) to a high value (e.g., 200 Hz). Due to the combination of pole number and number of series turns switching/reconfiguration, a high torque at low speed (e.g., 0 rpm) and a high torque at high speed (e.g., 5,000 rpm) can be achieved, making mechanical gears obsolete. In addition, the output power of the motor can be increased at high speed in direct proportion to the speed increase.

Abstract: A multiple-winding induction machine may be used to obtain a reduced-speed-variation electric drive when using a variable-frequency power distribution system. Each winding may have a different number of poles. The winding with the smallest number of poles may operate the machine at the lowest bus frequency, while the winding with the largest number of poles may operate the machine at the highest bus frequency. In one embodiment, a third winding, with a middle number of poles, may operate the machine at the middle frequency ranges. The speed of the induction machine is a function of the electrical frequency and the number of the winding poles. Therefore, the operating speed range can be reduced by switching from one winding to another. According to the present invention, windings with different numbers of poles can be designed to achieve different reductions in speed variation.

Abstract: The machine in accordance with the present disclosure is an AC machine whose pole numbers can be switched (from pole p1 to pole p2), and whose number of series turns per phase N can be switched say from N0=Nrated to N1=N0/2. Furthermore, it employs an inverter so that the frequency can be changed from a low value (e.g., 5 Hz) to a high value (e.g., 200 Hz). Due to the combination of pole number and number of series turns switching/reconfiguration, a high torque at low speed (e.g., 0 rpm) and a high torque at high speed (e.g., 5,000 rpm) can be achieved, making mechanical gears obsolete. In addition, the output power of the motor can be increased at high speed in direct proportion to the speed increase.

Abstract: A motor includes a stator core, a rotor in rotational relationship with the stator core and a main winding on the core. In one form, the main winding includes a 4-pole configuration and an 8-pole configuration and the motor has a 4-pole auxiliary winding on the core. A switching circuit selectively simultaneously energizes a portion only of the 4-pole configuration of the main winding and the 4-pole auxiliary winding when starting the motor for energizing the main winding in the 8-pole configuration. In another form, the main winding includes a 2-pole configuration and an 4-pole configuration and the motor has a 2-pole auxiliary winding on the core. In this latter form, the switching circuit selectively simultaneously energizes a portion only of the 2-pole configuration of the main winding and the 2-pole auxiliary winding when starting the motor for energizing the main winding in the 4-pole configuration.

Abstract: A dual stator winding induction machine has two windings with input terminals which are supplied separately with drive power. The two stator windings have a different number of poles to essentially eliminate the magnetic coupling between the two windings and to decouple the torques produced by each set of windings. Power is supplied to the two windings by two separate variable frequency inverter drives to provide two independently controllably torque components. At low speed, the power supplied to one of the windings can produce torque which opposes the torque from the power applied to the other winding, so that very low speed and standstill operation can be achieved while the frequency of the power supplied by the inverters is always greater than the minimum frequency. At higher operating speeds, power is supplied to the two windings so that the torque from the windings adds. The dual stator machine can be built with minimal modifications to standard winding configurations.

Abstract: A speed reduction switch for a multiple speed induction motor includes a speed selector switch and a delay element. As the motor is switched from a high speed to a lower speed, the delay element temporarily prevents electrical connection of a motor auxiliary winding for low speed operation. The motor is therefore de-energized and slows down. After a preselected delay, the delay element connects the motor auxiliary winding when the motor is at a lower speed so that little magnetic braking of the motor occurs, and the motor smoothly transitions from a higher speed to a lower speed.

Abstract: A method of and system for controlling an induction motor detects input frequency to the motor and connects windings of the motor in one of a plurality of configurations in dependence upon the detected frequency.

Abstract: A high-speed constant-horsepower motor includes a rotor and a stator having a plurality of groups of windings which are separately driven. In one mode of operation, the polarity of the voltage applied to each winding is such that the windings behave as distinct electromagnets, each defining a separate magnetic pole. In another mode of operation, the polarity of voltage applied to some of the windings is reversed, such that pairs of adjacent windings behave as single electromagnets. In the latter mode, the effective number of magnetic poles is reduced by a factor of two. Thus, the effective number of magnetic poles of the motor can be varied electronically, even while the motor is operating. The invention makes it possible, in one example, to operate the motor as an eight-pole motor at low speeds, and as a four-pole motor at high speeds. The effective motor constants are changed appropriately from eight-pole to four-pole modes.

Abstract: A brushless DC motor useful as a driving source of a refrigerant compressor of a refrigerating apparatus or a fan. A position detecting means generates a control signal by detecting the terminal voltage on input-output terminals current to three-phase rotor drive coils. Filters convert the detected terminal voltages to smoothed signals. A mixing means generates three kinds of mixed signal from the smoothed signal and comparing means generates the control signal for switching a current path to the three-phase coils by a signal made by comparing the mixed signal with the smoothed signal. The current path to the coils is switched by a switching-driving part in turn on the basis of the control signal of the position detecting means.The present invention provides a brushless DC motor wherein current flowing to the drive coils can be switched without special position detecting elements.