A drive device of a synchronous motor includes a power converter that drives the synchronous motor by sequentially applying positive and negative voltages to respective phases of the synchronous motor; a current detection unit that detects a phase current; and a magnetic pole position estimation unit estimating a magnetic pole position of a rotor based on the phase current. The magnetic pole position estimation unit acquires maximum and minimum values of the phase current while the synchronous motor is stopped, calculates a first magnetic pole position from a subtracted value of an absolute value of the maximum and minimum values, calculates a second magnetic pole position from an added value of the absolute value of the maximum and minimum values, discriminates a polarity of a magnet of the rotor, and estimates an initial magnetic pole position of the rotor from the polarity and the second magnetic pole position.

A rotary machine control device includes: a magnetization characteristics determiner that determines a magnet phase of a magnet flux based on an estimated magnetic flux and a detection current, and determines a qm-axis magnetic flux of the estimated magnetic flux, a qm-axis current of the detection current, and a harmonic component of a magnet phase using a dm-qm coordinate system with a dm axis representing the magnet phase and a qm axis representing a phase shifted by 90 degrees from the magnet phase; a ripple compensation determiner that determines a ripple compensation phase using a ripple compensation torque obtained based on the qm-axis current and the harmonic component; a command phase determiner that determines a command phase based on the ripple compensation phase and a torque command; and a command magnetic flux generator that generates a command magnetic flux based on a command amplitude and the command phase.

The present disclosure provides a system and a method for detecting a fault of an operation of a synchronous motor. The method includes collecting an electrical input and measurements associated with the operation of the synchronous motor caused by the electrical input. The method further includes determining sequences of points defining a mutual position between a stator and a rotor of the synchronous motor that results in magnetostatic determined as a weighted summation over real-space basis functions parameterized on pairs of adjoint points in the determined sequence of points and weighted with a surface charge density between corresponding adjoint points, such that the resulted magnetostatic explains the measurements of the operation of the synchronous motor given the electrical input. Further, the method includes determining the fault of the operation of the synchronous motor based on the mutual position between the stator and the rotor of the synchronous motor.

A method, system, and apparatus are provided for determining mechanical characteristics of an electric motor and mechanical load with a speed signal modulator, FOC current loop, sensor-less rotor speed estimator, and speed signal demodulator which are configured to provide a q-axis AC reference current, q-axis DC reference current, estimated maximum AC rotor speed, estimated DC rotor speed, estimated phase angle of the AC rotor speed component, and torque constant to a mechanical characteristics estimator which is configured to determine a plurality of load torque parameters for the electric motor and mechanical load which include a combined moment of inertia parameter, a combined static friction, and a combined viscous friction coefficient parameter.

According to one embodiment, a motor drive apparatus includes a first inverter, a second inverter, and a controller. This controller rotationally moves, at the time of startup of a motor, a rotor of the motor to an initial position by DC excitation of supplying DC exciting currents from the first and second inverters to the phase windings of the motor and, after this rotational movement, PWM-controls switching of the first and second inverters in such a manner that a rotational speed of the rotor becomes a target rotational speed. Then, the controller carries out the DC excitation fey which a zero-axis current in each of the phase windings becomes approximately zero.

A method for detecting an initial position of a rotor of a permanent magnet synchronous motor in a no-load environment can comprise the steps of: estimating a temporary initial position α′ by means of aligning a d axis; measuring a first voltage command which is output by performing velocity control within predetermined velocity ranges with respect to the forward direction of a motor on the basis of the temporary initial position α′; measuring a second voltage command which is output by performing velocity control within the predetermined velocity range with respect to the reverse direction of the motor on the basis of the temporary initial position α′; calculating respective variations of the first voltage command and second voltage command, and calculating a compensation angle α″; and calculating an initial position α of the rotor on the basis of the sum of the temporary initial position α′ and compensation angle α″.

Described is a method of controlling operation of a synchronous motor. The method comprises, during constant power/speed motor operation, determining a value of a stator voltage (v.sub.s.sup.2) for an orthogonal rotating reference frame of the motor. Comparing the value of the determined stator voltage (v.sub.s.sup.2) to a threshold voltage (v.sub.s.sup.2.sub._max1), said threshold voltage (v.sub.s.sup.2.sub._max1) having a value between that of a maximum stator voltage (v.sub.s.sup.2.sub._max0) for a basic speed mode of operation of the motor and that of a maximum stator voltage (v.sub.s.sup.2.sub._max2) of the motor closed loop controller. If the determined value of the stator voltage (v.sub.s.sup.2) is greater than or equal to the value of the threshold voltage (v.sub.s.sup.2.sub._max1), then controlling operation of the motor in a flux weakening mode of operation until a value of a current component (i.sub.d−Δi.sub.d) in a d-axis reaches a maximum negative value (−i.sub.dmax), or until the value of the stator voltage (v.sub.s.sup.2) is less than the value of the threshold voltage (v.sub.s.sup.2.sub._max1).

A detection sensor including an alternating current (AC) permanent magnet synchronous motor (PMSM) housed in a casing, a motherboard and an AC servo controller with a permanent memory in electronic communication with the PMSM, and a shaft extending from the PMSM configured to rotate a sensing needle wherein the sensing needle is configured to sense an object in its rotation.

A rotor temperature monitoring method and system for a permanent magnet synchronous motor are provided. According to the method and system, an a-phase line current and a b-phase line current of a stator of a permanent magnet synchronous motor are obtained as a first line current and a second line current; further, a line voltage between the a-phase and the b-phase of the stator is obtained and a rotating speed of the rotor of the permanent magnet synchronous motor is obtained; and then, the first line current, the second line current, the line voltage, the rotating speed of the rotor, an inductance parameter of the permanent magnet synchronous motor and a temperature characteristic equation of a permanent magnet of the rotor are substituted into a preset rotor permanent magnet temperature expression to calculate and obtain the temperature of the rotor.

A motor drive device includes a plurality of control systems that individually supply drive currents to a plurality of coil groups included in a motor. The motor drive device independently sets the current command values for the respective control systems. Based on the set current command values, drive instructions are supplied to drive circuits of inverters with respect to the respective control systems, thereby supplying drive currents from the inverters to the coil groups. The motor drive device detects a failure in any of the inverters and the coil groups with respect to each control system, and stops only the failed control system or causes only the failed control system to fall back. The motor drive device further includes a main computing device, and an auxiliary computing device. Consequently, if the auxiliary computing device is normal even in case the main computing device fails, driving of the motor can be continued using one or some of the control systems.