A system of calculating temperature may include: a motor including a housing having opened ends, a cover connected to the housing to close at least one of the opened ends, a shaft rotatably disposed in the housing and having one end which penetrates through a center portion of the cover, a rotor fixed on an exterior circumference of the shaft in the housing and the cover, a stator fixed on an interior circumference of the housing, and an air gap formed between an exterior circumference of the rotor and an interior circumference of the stator; an input portion receiving a real time input and a predetermined input; and a control portion establishing a thermal equivalent circuit using the inputs of the input portion and convection or conduction characteristics between constituent elements of the motor, and calculating a temperature of each constituent element using the thermal equivalent circuit.

Eddy current retarder equipment (1) able to be carried on board a vehicle, includes: a stator assembly (2), including inductor windings (23) forming a circuit (4), a rotor assembly (3) designed to be mounted on a transmission shaft of the vehicle, including an armature (31) facing the inductor windings (23), control elements (6) for establishing a linear setpoint (?), excitation elements (7) for exciting the inductor circuit (4) from an electric power source (5) of the vehicle as a function of the setpoint (?), a speed sensor (9) for supplying information relating to the rotational speed (?) of the rotor assembly (3), a sensor (10) of the strength of current supplied to the inductor circuit (4), processing elements (8) for estimating, at a given moment (t), the retarding torque supplied by the equipment (1).

A temperature determination method for magnet temperatures on magnets of electric motors has a test mode. A first voltage is applied to a test winding of a test motor with test magnets for impressing a first voltage-time area at first angles of a test motor rotating field. The test magnets are subject to a predefined magnet temperature. First current values are ascertained at the first angles and stored based on the predefined magnet temperature. In a normal mode, a second voltage is applied to a motor winding of an operations motor with motor magnets for impressing a second voltage-time area at second angles of a motor rotating field. The motor magnets have an operation-dependent magnet temperature. Second current values are determined at the second angles and stored based on the operation-dependent magnet temperature. The operation-dependent magnet temperature is determined by comparing a second current value with a first current value.

A motor temperature and torque estimation device comprises: a temperature sensor; a losses estimation circuitry to estimate an iron loss; a first temperature estimation circuitry to estimate a first magnet temperature from the estimated iron loss and a sensor's detected temperature; a second temperature estimation circuitry, to input into a magnet's magnetic flux calculator thereinside motor's modified inductance, to estimate a second magnet temperature from magnet's magnetic flux calculated through voltage equations; a magnet-temperature estimation circuitry to estimate a motor's magnet temperature from the first and second magnet temperatures; a magnet's magnetic estimation circuitry to estimate magnetic flux based on the calculated/modified one, the motor's estimated magnet temperature and temperature characteristics, and to output the estimated magnetic flux into the losses estimator; and a torque estimation circuitry to estimate torque based on the estimated magnetic flux and iron loss, wherein a motor's magnet temperature(s) and torque are estimated.

In accordance with one embodiment, a method of controlling a braking of a rotor of an electric motor comprises operating an electric motor in a first mode at an inefficient operating point or inefficient operating curve of a quadrature-axis current versus a direct-axis current such that the braking of the electric motor occurs at a rate based on a rate proportional to or less than the total available power losses in the motor, the inverter, or both. The electric motor is operated in the first mode until the observed rotor speed of the electric motor is less than or equal to a threshold speed; thereafter a multi-phase short circuit can be applied.

Provided are: a synchronous machine having permanent magnets as a field system; a stress estimator that estimates stress acting on the permanent magnets; and a first magnet temperature corrector that calculates an amount of demagnetization due to stress of armature interlinkage magnetic flux on the basis of the estimated stress, estimates an amount of demagnetization due to stress of the armature interlinkage magnetic flux on the basis of the rotor position of the synchronous machine, a current command and a voltage command, and the amount of demagnetization due to stress of the armature interlinkage magnetic flux; and outputs a permanent magnet temperature estimated value after correction, having factored therein the amount of demagnetization due to stress of the armature interlinkage magnetic flux from the estimated armature interlinkage magnetic flux.

Provided is a motor drive control device which is capable of properly driving and controlling a permanent magnet synchronous motor capable of independently controlling each phase in accordance with the temperature of the permanent magnet.

A motor drive control device 500 is a device which drives and controls a permanent magnet synchronous motor 100 in which each phase is independently controlled, and includes a 0-axis current calculation unit 305 which calculates and outputs a 0-axis current i.sub.z on the basis of a motor current; a 0-axis current determination unit 306 which compares and determines a reference 0-axis current value i.sub.zs which is the 0-axis current value when the temperature of a permanent magnet provided in the permanent magnet synchronous motor 100 is a reference temperature with the calculated 0-axis current i.sub.z; and a switching signal generation unit 301 which drives and controls inverters 210a, 210b, and 210c on the basis of the result of comparison determination of the 0-axis current determination unit 306.

An inverter control device that controls an inverter unit that converts a DC voltage from a converter unit to an AC voltage and supplies the AC voltage to the DC motor includes a storage unit that stores therein information regarding a synchronization-loss limit; a synchronization-loss limit-current calculation unit that calculates the limitation value on the synchronization-loss limit current on the basis of the magnet temperature of the DC motor, the bus voltage to be applied to the inverter unit, and the information regarding a synchronization-loss limit; and a control unit that compares the primary current to be input to the converter unit with the limitation value and that, when the primary current exceeds the limitation value, outputs an adjustment command to adjust the operating frequency of the DC motor such that the primary current becomes equal to or less than the limitation value.

Techniques for motor magnet degradation controls and diagnostics are disclosed. An exemplary technique determines q-axis current, d-axis current, q-axis voltage, and/or d-axis voltage of a permanent magnet motor based upon sensed current and voltage information of the motor. This information is utilized to determine flux information. The flux information is utilized in evaluating collective state conditions of a plurality of motor magnets and evaluating localized state conditions of a subset of the plurality of motor magnets. The evaluations can be used to identify degradation or damage to one or more of the magnets which may occur as a result of elevated temperature conditions, physical degradation, or chemical degradation.

A method for measuring the temperature of a permanent magnet disposed on a rotor of an electrical machine, a magnetic property of the permanent magnet dependent on the temperature of the permanent magnet being sensed and the temperature of the permanent magnet being ascertained therefrom, and to an electrical machine, a processing unit, and a computer program for carrying it out.