A transient current planning method for an ultra-high-speed permanent magnet synchronous motor for improving speed regulation response capabilities is provided. A transient current planning module uses a voltage model considering transient current changes to calculate current instruction values of an ultra-high-speed permanent magnet synchronous motor under MTPA control, general flux-weakening control, and MTPV control; a mode switching condition judgment subsystem judges whether a control mode is MTPA control or general flux-weakening control, or MTPV control, and sends d- and q-axis current instruction values in the corresponding control mode to a voltage decoupling control module; and the voltage decoupling control module calculates d- and q-axis voltage instruction values for controlling the motor, so as to realize control over the ultra-high-speed permanent magnet synchronous motor.

The present disclosure disclose a vector flux weakening control system for a permanent magnet synchronous motor of an electric drive system, which includes a current closed-loop regulation module, a modulation index deviation calculation module, a current characteristic point setting module, a current compensation vector angle calculation module, a current compensation vector amplitude calculation module, a current compensation vector calculation module and a current instruction correction module. In the present disclosure, the three-phase short-circuit current of the motor is taken as the end point of flux weakening regulation, and when voltage saturation occurs, the motor control system can exit saturation; since an inverter supplies power through a power battery bus at the terminal of the motor, the terminal voltage thereof will not be as low as zero, and there is a large margin to deal with abnormal factors; by introducing a dq current and correcting it at the same time, the pressure of resisting voltage saturation can be distributed to the dq current, thus avoiding excessive deviation of an output torque caused by excessive uniaxial current regulation. According to the present disclosure, the influence of the flux weakening control process on the output torque of the drive system is reduced as much as possible while ensuring the safety of the drive system.

A method for operating a separately excited electric motor, which includes a rotor and a stator, includes the following: determining an electrical characteristic variable of the rotor and an electrical characteristic variable of the stator, calculating an initial setpoint voltage value for the stator based on a setpoint current value, a measured current value, and the determined electrical characteristic variables of the rotor and the stator, checking, based on the calculated initial setpoint voltage value, whether there is an electrical fault, in particular a shorted coil, at the rotor, and providing a fault message and/or disconnecting the electric motor if a fault has been identified.

The object of the invention is a method of controlling a permanent-magnet synchronous or synchro-reluctant three-phase rotary machine (4), comprising the following steps: measuring a current (i.sub.A, i.sub.B, i.sub.C) flowing through each phase of a stator of rotary machine (4), first calculating, by use of a single proportional-integral controller, of a switching control signal for controlling an inverter (10), according to each measured current (i.sub.A, i.sub.B, i.sub.C), and of a target value (T.sub.ref) of a mechanical torque provided by the rotary machine (4) or of a target value of an angular speed of a rotor of rotary machine (4) in relation to the stator wherein the inverter (10) is configured to convey electrical energy between a continuous electrical energy source (8) and each phase of the stator of rotary machine (4), and controlling the inverter (10) by use of the calculated switching control signal.

A motor driving device includes: a connection switcher that has an electromagnetic contactor connected to a winding of a motor and switches connection condition of the winding by switching condition of the electromagnetic contactor; an inverter to apply an output voltage as an AC voltage to the winding via the connection switcher; a short-circuiting circuit having a rectification circuit and a switch; and a controller to control the electromagnetic contactor, the inverter and the switch, wherein a circulating circuit is formed by the short-circuiting circuit and the winding when the switch is set at ON, and the connection switcher switches the connection condition of the winding in a period in which the output voltage of the inverter is set at zero in a rotating operation of the motor and a current caused by the rotating operation circulates in the circulating circuit.

An electric working machine of an example of the present disclosure includes: a motor; a power supply portion; a controller; and a voltage detector. The power supply portion generates a DC voltage to drive the motor by rectifying an AC voltage supplied from an AC power source and smoothing by a capacitor. The controller controls energization of the motor. The voltage detector detects the AC voltage. The controller is configured to interrupt the energization when the voltage detector does not detect the AC voltage.

A system for regulating the power supply of the electric, motor incorporated in an airless paint spray unit so as to enhance the efficiency and performance of the airless paint spray unit. The system includes the utilization in the rector control for the electric motor driving the pump of the airless paint spray unit of an active Power Factor Correction (PFC) switching power supply adapted to regulate the electrical power supplied to the motor.

An apparatus for controlling an AC power supply for an electric motor, said AC power supply being derived from a DC voltage. The apparatus comprises a comparer configured to provide a comparison of a modulation index of a motor control signal with a reference value. This current data provider is configured to provide current data based on a torque demand signal; a speed signal indicating the speed of rotation of the AC motor; and an indication of the DC voltage modified on the comparison for control of the motor control signal which is based on the motor current data.

An object is to provide a permanent magnet motor controller capable of suppressing the rotary bending vibration that occurs in the permanent magnet motor effectively with simple configuration. A permanent magnet motor controller uses the dq coordinate conversion. A dq target current setting part adds the current component (i*.sub.da) that cancels the magnetic attractive force acting in the radial direction of the rotational shaft of the rotor of the permanent magnet motor to the d-axis target current value, whereby the eccentricity of the rotational shaft of the rotor is reduced.

The present invention provides a device and a method for changing over an electric machine from the regular operating mode into the open-circuit mode. In order to avoid excessive increases in voltage and associated adverse effects on the electric machine and the other components, in particular batteries, a further control phase is introduced between the end of the regular operating mode and the freewheeling mode, during which further control phase the voltage at the terminals of the electric machine is continuously adjusted from the voltage previously set in the regular operating mode to the expected open-circuit voltage of the electric machine.