93 results about "Polyphase coil" patented technology

This invention provides a motor driving apparatus that made it possible to reduce torque ripples including those attributed to load variation of the motor and an associated method for control of motor revolution. An output stage to a multiphase DC motor is comprised of power elements to supply output voltages to multiphase coils and a predriver to supply drive voltages to the power elements. A resistor means detects a current flowing through the power elements. A supply current detector detects a voltage signal produced across the resistor means as a supply current, using a high-speed ADC and a moving average filter. An output controller generates a PWM signal with a frequency lower than the frequency of the high-speed ADC so that the current detected by the supply current detector conforms to a current signal indicating a motor revolving speed and transfers the PWM signal to the output stage.

A method for detecting deterioration of a permanent magnet in an electric motor is characterized by peak current measuring steps and a determination step. In the first peak current measuring step, when the electric motor is started, a first pulsed voltage is applied to the multi-phase coils so as to generate magnetic flux directed in the same direction as generated by the permanent magnet and a first peak current is measured. In a second peak current measuring step, a second pulsed voltage is applied to the multi-phase coils so as to generate magnetic flux directed in the direction opposite to the direction in which magnetic flux is generated by the permanent magnet and a second peak current is measured. In a determination step, it is determined whether or not the permanent magnet is deteriorated based on the difference of the absolute value between the first and the second peak currents.

There is provided a motor control device configured to control an energization state of a coil of each phase for driving a stepping motor having multiple phase coils. The motor control device includes a measuring unit configured to measure a back electromotive voltage induced at a coil of a phase for which energization is stopped, among the multiple phase coils, an acquiring unit configured to acquire temperature information on temperature of the stepping motor or on temperature corresponding to the temperature of the stepping motor, and a detecting unit configured to detect whether the stepping motor is out of step or not based on a result obtained by the measuring unit and the temperature information acquired by the acquiring unit.

An electric motor includes a cylindrical stator that is formed with a plurality of slots. The cylindrical stator has polyphase coils that are formed by winding a plurality of conductive wires in the slots to have polyphase, a wire bundle and an insulating tube covering the wire bundle. Each conductive wire includes a core wire and an insulator that covering the core wire. The wire bundle has a drawing portion, a connecting portion and an elongated portion that is elongated between the drawing portion and the connecting portion for increasing creepage distance between the connecting portion and the housing thereby to increase insulation resistance. The connecting portion of the wire bundle provides a neutral point of the electric motor. The elongated portion and the connecting portion of the wire bundle are covered with the insulating tube.

An electronic braking and energy recycling system associated with a direct current (DC) brushless motor, characterized in that when an electronic braking task is launched, a phase voltage occurred in an inverse mode is applied onto a motor coil corresponding thereto and a gate voltage signal with positive and negative cycles is used to control an upper-side and lower-side branches to switch as compared to each other in the system, so as to redirect a current flown through the motor back to a power source end. In this invention, a controllable inverse torsion is achieved, enabling an electrical machine to be braked smoothly and reliably when necessary. As such, a dynamic power of the motor can be recycled at a maximum rate and thus the purpose of energy recycling is achieved. In addition, no complex circuitry configuration owing to the multi-phase coils is required.

Provided is an electric power steering device that is capable of estimating coil temperatures more accurately for a polyphase motor including multi-system motor windings, with consideration also givento a heat-transfer phenomenon between a control board and coils in addition to heat-transfer phenomena between respective phases of polyphase coils, and that is also capable of estimating coil temperatures even when there is an abnormality in one of the systems. The electric power steering device comprises: a temperature sensor that detects a board temperature of a control board; and a coil temperature estimation unit that finds, from motor currents of respective phases of a polyphase motor, coil heat-generation amounts of the respective phases and a board heat-generation amount of the control board, and that estimates coil temperatures of the respective phases from the coil heat-generation amounts, the board heat-generation amount, and the board temperature on the basis of heat-transferphenomena between the respective phases caused by temperature differences between coils of the respective phases and a heat-transfer phenomenon between the coils and the control board. In cases wherethere is an abnormality in one of the systems, the coil temperature estimation unit estimates the coil temperatures from the board temperature and values obtained by correcting the coil heat-generation amounts and the board heat-generation amount found in the normal system. The heat-transfer phenomenon is expressed by a differential equation.