A method for switching on a multi-phase electrical machine in a motor vehicle, the multi-phase electrical machine having a rotor having a rotor winding, and a stator having a multi-phase stator winding; a phase voltage having a phase voltage vector being applied, in a PWM operating mode, to the stator winding, said vector corresponding in terms of absolute magnitude and direction to a pole wheel voltage vector of a pole wheel voltage; the rotor winding being energized by an excitation current; and the PWM operating mode being deactivated, and a block operating mode for application of the phase voltage being activated, when at least one parameter influencing the pole wheel voltage reaches a threshold value.

An electric motor drive apparatus comprising a voltage converter component arranged to receive a supply voltage signal and output a bus voltage signal, and a motor driver component arranged to receive the bus voltage signal and generate at least one drive signal for an electric motor from the bus voltage signal. The motor driver component is arranged to output a bus voltage feedback signal to the voltage converter component. The voltage converter component is arranged to regulate a voltage level of the bus voltage signal based at least partly on the bus voltage feedback signal output by the motor driver component.

A microcomputer includes a current command value setting unit configured to set a two-phase current command value in a two-phase rotating coordinate system for each of PWM cycles in a current control cycle, and an open-loop control unit configured to calculate a two-phase voltage command value for each of the PWM cycles, according to a motor voltage equation, based on the two-phase current command value for each of the PWM cycles that is set by the current command value setting unit and a rotation speed of an electric motor. The two-phase voltage command value is a command value of voltage that is to be applied to the electric motor.

A method for switching on a multi-phase electrical machine in a motor vehicle, the multi-phase electrical machine having a rotor having a rotor winding, and a stator having a multi-phase stator winding; a phase voltage having a phase voltage vector being applied, in a PWM operating mode, to the stator winding, said vector corresponding in terms of absolute magnitude and direction to a pole wheel voltage vector of a pole wheel voltage; the rotor winding being energized by an excitation current; and the PWM operating mode being deactivated, and a block operating mode for application of the phase voltage being activated, when at least one parameter influencing the pole wheel voltage reaches a threshold value.

A power tool that includes a housing, a brushless motor, a power switching circuit, and an electronic controller. The brushless motor is within the housing. The brushless motor includes a rotor and a stator. The rotor is coupled to a motor shaft arranged to rotate about a longitudinal axis. The motor shaft is arranged to produce a rotational output to a drive mechanism. The power switching circuit provides a supply of power from a battery pack to the brushless motor. The electronic controller is configured to determine a parameter associated with the battery pack, assign a classification to the battery pack based on the determined parameter, and control field weakening applied to the brushless motor based on the classification of the battery pack.

A motor control apparatus includes: a booster circuit electrically connected to a battery; and an inverter electrically connected to the booster circuit at one end and electrically connected to a motor at another end. The motor control apparatus is provided with a controller configured to control the inverter to output square wave voltage to the motor, thereby driving the motor. The controller is configured to control the inverter to temporarily invert voltage polarity associated with the square wave voltage, on the basis of a phase difference between a voltage command associated with the motor and an electric current associated with the motor, on condition that an operating point of the motor is in a resonance region, which is an operation area in which resonance is generated in the booster circuit.

A drive system for a brushless DC motor having a rotor includes at least one permanent magnet and a stator including at least one phase winding. The system has a drive circuit including a switch associated with the winding for varying the current passing through the winding; a rotor position sensor arranged to sense the position of the rotor; and a controller arranged to provide drive signals to control the switch. The drive system is further arranged to receive a temperature signal that has a value dependent upon the temperature of the at least one magnet of the rotor. The controller is arranged to vary the phase of the current passing through the winding relative to the rotor position dependent upon the temperature of the rotor magnet.

The present invention provides a bidirectional high frequency speed drive configured to connect to a utility grid and an electrical machine. The bidirectional high frequency variable speed drive comprises a plurality of inductors each configured to connect to respective phase outputs of the electrical machine, a first plurality of power switches connected to the plurality of inductors, a second plurality of power switches connected to the plurality of inductors, and a controller connected to the first and second plurality of power switches. The controller can generate control signals based on an operating status and a predetermined operating status of the electrical machine. The first output of the first plurality of power switches can be interleaved to a second output of the second plurality of power switches. The present invention also provides methods for the bidirectional high frequency speed drive and apparatuses used to perform the methods of the present invention.

A rotary electric machine includes a stator and a rotor. The rotor has at least one permanent magnet arranged in a d-axis magnetic path. The rotor includes a magnetic gap part located between the permanent magnet arranged in the d-axis magnetic path of one pole and an adjacent magnet with a different polarity, such that a d-axis magnetic flux forms a d-axis bypass passing through an area other than the permanent magnet. The d-axis bypass provides a magnetic resistance in a d-axis direction that is set below a magnetic resistance in a q-axis direction that is orthogonal to the d-axis resistance.

A method that involves determining the maximum operating speed of an electric motor under varying torque conditions, specifically at speeds surpassing its rated speed. Initially, the motor is operated at its highest speed across different torque values, establishing a data set of real measurement points. These points illustrate the relationship between the maximum motor speed and the applied torque. A coefficient (COF), ranging from 0 to 1 and dependent on motor characteristics, is selected. Two curves are then established: the first for lower maximum speeds, represented by

[00001]${}_{ref}=\frac{{\mathrm{COFP}}_{nom}}{T_{meas}},$

and the second for torques below a defined limit torque T.sub.lim expressed as

[00002]${}_{ref}=\frac{{\mathrm{COFP}}_{nom}}{f\left(T_{meas}\right)},$

where is a polynomial function derived from the measurement points. The appropriate curve is then used to ascertain the maximum motor speed for a given torque, based on whether the torque is greater or lesser than T.sub.lim.