A control system for monitoring a motor and wheel drive gearbox of an irrigation system drive train. The control system includes a motor sensor for sensing an operating state of the motor and a gearbox sensor for sensing an operating state of the wheel drive gearbox. If the motor operating state exceeds a motor operating state threshold or changes too quickly, or if the wheel drive gearbox operating state exceeds a wheel drive gearbox operating state threshold or changes too quickly, the control system operates the drive train at a reduced capacity or in a modified mode such that the operating state is not exceeded or does not change too quickly.

An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

Method for operating a power converter for a permanently excited electric machine, wherein temperature information, which describes a temperature of at least one permanent magnet of the electric machine, is determined by means of an observer as a function of operating parameters of the electric machine, and the power converter is controlled as a function of the temperature information, wherein a computing device, which handles processes in time slices, carries out a first process in a first time slice for detecting parameter values for determining the operating parameters and carries out a second process, which determines the temperature information, in a second time slice, which is retrieved less frequently than the first time slice.

Methods and apparatuses for determining a rotor temperature of a permanent magnet synchronous machine (PSM) of an electrically driven vehicle are described.

A method, system, and apparatus for controlling and regulating operation of a permanent magnet rotary electric machine including a stator and a rotor includes determining a first reactive power term associated with the electric machine based upon voltage, and determining a second reactive power term associated with the electric machine based upon flux. A first motor temperature associated with the electric machine is determined based upon the first and second reactive power terms, and power output from the permanent magnet electric machine is controlled based upon the first motor temperature.

A method, system, and apparatus for controlling and regulating operation of a permanent magnet rotary electric machine including a stator and a rotor includes determining a first reactive power term associated with the electric machine based upon voltage, and determining a second reactive power term associated with the electric machine based upon flux. A first motor temperature associated with the electric machine is determined based upon the first and second reactive power terms, and power output from the permanent magnet electric machine is controlled based upon the first motor temperature.

In a rotating electrical machine, in particular a generator, different components, such as, for example, rotor, stator rod and end zone, are cooled as required by associated external fans, whereby the cooling power requirement is reduced. The method for cooling includes a plurality of cooling fans arranged for cooling different components of the machine, wherein a cooling fan is individually controlled in its cooling performance in accordance with the temperature of the associated component.

To provide a motor control method ensuring that dragging loss at the time of high rotation can be reduced. A motor control method, wherein a composite permanent magnet has a core part and a shell part, the Curie temperature of one of the core part and the shell part is T.sub.c1 K, and the Curie temperature of another is T.sub.c2 K, and wherein when the magnitude of the reluctance torque is equal to or greater than the magnitude of the magnet torque, the temperature of the composite permanent magnet is set at T.sub.s K that is (T.sub.c1100) K or higher and lower than T.sub.c2 K and when the magnitude of the reluctance torque is less than the magnitude of the magnetic torque, the temperature of the composite permanent magnet is set at lower than the temperature T.sub.s K or T.sub.c1 K, whichever is lower.

To provide a motor control method ensuring that dragging loss at the time of high rotation can be reduced. A motor control method, wherein a composite permanent magnet has a core part and a shell part, the Curie temperature of one of the core part and the shell part is T.sub.c1 K, and the Curie temperature of another is T.sub.c2 K, and wherein when the magnitude of the reluctance torque is equal to or greater than the magnitude of the magnet torque, the temperature of the composite permanent magnet is set at T.sub.s K that is (T.sub.c1100) K or higher and lower than T.sub.c2 K and when the magnitude of the reluctance torque is less than the magnitude of the magnetic torque, the temperature of the composite permanent magnet is set at lower than the temperature T.sub.s K or T.sub.c1 K, whichever is lower.

A driving apparatus includes: an inverter unit generating a three-phase alternating-current voltage from a direct-current voltage in accordance with a drive signal based on a voltage command and outputting the three-phase alternating-current voltage to a permanent-magnet motor, the permanent-magnet motor including a permanent magnet; a current detection unit detecting a motor current flowing through the permanent-magnet motor; and a control unit generating the voltage command to control an operation of the inverter unit and estimating a temperature of the permanent magnet to perform a protection operation on the inverter unit on the basis of the motor current and an overcurrent protection threshold. The control unit sets the overcurrent protection threshold on the basis of a magnet temperature estimated value of the permanent magnet and any one of a control computation period of the control unit, an output voltage frequency of the inverter unit, and a carrier frequency based on the output voltage frequency of the inverter unit.