In one aspect, embodiments of the invention are directed to a multi-pole rotor of a variable-flux memory motor (VFMM) that includes: a rotor core; and a plurality of poles. Each of the poles includes: one or more soft rotor magnets; a first ferrous wedge; and a second ferrous wedge. The one or more soft rotor magnets are disposed between the first and second ferrous wedges in a circumferential direction of the rotor.

In one aspect, embodiments of the invention are directed to a multi-pole rotor of a variable-flux memory motor (VFMM) that includes: a rotor core; and a plurality of poles. Each of the poles includes: one or more soft rotor magnets; a first ferrous wedge; and a second ferrous wedge. The one or more soft rotor magnets are disposed between the first and second ferrous wedges in a circumferential direction of the rotor.

A control device of a permanent magnet synchronous motor that is a control device of a sensorless-type permanent magnet synchronous motor in which a rotor using a permanent magnet rotates by a rotating magnetic field caused by a current flowing in an armature includes: a driver that applies a voltage to the armature and drives the rotor; an initial position estimator that estimates an initial position which is a magnetic pole position of the rotor that is stopped; and a controller that controls the driver so as to apply a pulse train including a voltage pulse for searching the initial position for each of n angle positions dividing a search range of an electrical angle of 360 degrees to the armature, wherein the pulse train includes a first pulse and a second pulse.

A control device of a permanent magnet synchronous motor that is a control device of a sensorless-type permanent magnet synchronous motor in which a rotor using a permanent magnet rotates by a rotating magnetic field caused by a current flowing in an armature includes: a driver that applies a voltage to the armature and drives the rotor; an initial position estimator that estimates an initial position which is a magnetic pole position of the rotor that is stopped; and a controller that controls the driver so as to apply a pulse train including a voltage pulse for searching the initial position for each of n angle positions dividing a search range of an electrical angle of 360 degrees to the armature, wherein the pulse train includes a first pulse and a second pulse.

In a method for operating an electric machine a first test signal is fed into the electric machine and a first response signal of the electric machine is measured. A first state variable for a rotor of a synchronous reluctance motor of the electric machine is determined as a function of the first response signal, and a second state variable for the rotor of the synchronous reluctance motor is determined. The first state variable and the second state variable are evaluated together.

In a method for operating an electric machine a first test signal is fed into the electric machine and a first response signal of the electric machine is measured. A first state variable for a rotor of a synchronous reluctance motor of the electric machine is determined as a function of the first response signal, and a second state variable for the rotor of the synchronous reluctance motor is determined. The first state variable and the second state variable are evaluated together.

In a sensorless control of a motor, due to the characteristic of a response frequency, an induced voltage, a magnetic pole position estimation gain, a current control gain, and a speed control gain are closely related. An object of the invention is to enable the induced voltage and the frequency characteristic of a magnetic pole position estimation system to be clearly designed and to theoretically and quantitatively design all of the control gains necessary for the sensorless control so as to solve a problem that a method of designing those parameters cannot be established and the parameters have to be adjusted in a try and error manner. A control device has an estimator estimating an estimation induced voltage and a phase error of a motor by applying an induced-voltage observer and a controller controlling the motor on the basis of the estimation induced voltage and the phase error.

In a sensorless control of a motor, due to the characteristic of a response frequency, an induced voltage, a magnetic pole position estimation gain, a current control gain, and a speed control gain are closely related. An object of the invention is to enable the induced voltage and the frequency characteristic of a magnetic pole position estimation system to be clearly designed and to theoretically and quantitatively design all of the control gains necessary for the sensorless control so as to solve a problem that a method of designing those parameters cannot be established and the parameters have to be adjusted in a try and error manner. A control device has an estimator estimating an estimation induced voltage and a phase error of a motor by applying an induced-voltage observer and a controller controlling the motor on the basis of the estimation induced voltage and the phase error.

A monitoring device for a reluctance machine includes a vector rotator for rotating a space phasor of the reluctance machine that depends on a voltage in a coordinate system that rotates with a negative fundamental frequency, a low-pass filter filtering the rotated space phasor and producing an output signal, and a signal evaluation device evaluating the output signal. A DC value of the produced output signal in the rotating coordinate system is monitored, and an error in operating the reluctance machine is identified when the DC value is above a predefined threshold value.

A monitoring device for a reluctance machine includes a vector rotator for rotating a space phasor of the reluctance machine that depends on a voltage in a coordinate system that rotates with a negative fundamental frequency, a low-pass filter filtering the rotated space phasor and producing an output signal, and a signal evaluation device evaluating the output signal. A DC value of the produced output signal in the rotating coordinate system is monitored, and an error in operating the reluctance machine is identified when the DC value is above a predefined threshold value.