The invention relates to an electric circuit (1) for an electric motor (2), the electric motor (2) having at least one stator (3) with at least three coils (4, 5, 6) and a rotor (7) with at least two magnetic poles (8, 9); the motor (2) being operable by means of the electric circuit (1) at least in the following two states (10, 11): a) in a first state (10), the coils (4, 5, 6) can each be energized with different currents of a three-phase system (12) and the rotor (7) can be set into rotation about an axis of rotation (13); b) in a second state (11), the coils (4, 5, 6) can be energized with an in-phase alternating current (14).

The invention relates to an electric circuit (1) for an electric motor (2), the electric motor (2) having at least one stator (3) with at least three coils (4, 5, 6) and a rotor (7) with at least two magnetic poles (8, 9); the motor (2) being operable by means of the electric circuit (1) at least in the following two states (10, 11): a) in a first state (10), the coils (4, 5, 6) can each be energized with different currents of a three-phase system (12) and the rotor (7) can be set into rotation about an axis of rotation (13); b) in a second state (11), the coils (4, 5, 6) can be energized with an in-phase alternating current (14).

Provided is a motor controller that can estimate the magnetic flux of a magnet without changing a current of an electric motor. A motor controller 1 includes a current detecting unit 15 that detects a current of an electric motor 5, a current stability determining unit 10 that determines whether or not a current detected by the current detecting unit 15 is stable, and a magnetic flux calculating unit (filters 8a to 8e, a current conversion unit 4b, a resistance calculating unit 9, a magnet magnetic flux estimating unit 11) that based on a determination made by the current stability determining unit 10 as to current stability, calculates the magnetic flux of a magnet of the electric motor 5, according to a voltage equation in a rotating coordinate system, to output the calculated magnet flux. The motor controller 1 further includes a control voltage output unit (a map 2, voltage instruction units 3a and 3b, a first three-phase conversion unit 4a) that outputs a control voltage to the electric motor 5, based on the magnetic flux of the magnet calculated by the magnetic flux calculating unit and on a torque instruction value.

A heat pump device includes an inverter control unit outputting PWM signals to an inverter; a current detection unit detecting a current value flowing in the inverter and outputting the current value after reducing a current value having a first frequency or higher in detected current value; and a drive-signal stop unit that, when the current value output from the current detection unit is equal to or larger than an interruption level, stops output of PWM signals to the inverter. Particularly, the inverter control unit generates a voltage command value such that the voltage command value becomes a value equal to or larger than a lower limit determined according to the first frequency and generates PWM signals based on generated voltage command value and a carrier signal, thereby causing a voltage output time to the motor to be a predetermined time or longer.

A heat pump device includes an inverter control unit outputting PWM signals to an inverter; a current detection unit detecting a current value flowing in the inverter and outputting the current value after reducing a current value having a first frequency or higher in detected current value; and a drive-signal stop unit that, when the current value output from the current detection unit is equal to or larger than an interruption level, stops output of PWM signals to the inverter. Particularly, the inverter control unit generates a voltage command value such that the voltage command value becomes a value equal to or larger than a lower limit determined according to the first frequency and generates PWM signals based on generated voltage command value and a carrier signal, thereby causing a voltage output time to the motor to be a predetermined time or longer.

A heating device intended to heat body, such as fluid contained in fluid circuit, the device including at least one electric heating element, as well as at least one control module to electrically power the heating element, the heating element being formed by propulsive winding circuit of direct-current electric motor which, when it is electrically powered by a direct supply voltage, generates drive force which tends to drive the motor in direction of displacement determined by the polarity of the supply voltage, and the control module including activation mode called heating oscillating mode, according to which the control module causes a warm-up of the propulsive winding circuit by Joule effect by applying at the terminals of the winding circuit an alternating supply voltage whose polarity switches, alternately and automatically, according to predetermined frequency called heating frequency, from a first polarity to opposite second polarity.

An apparatus for controlling a motor having a housing in which a stator and a rotor are disposed. The motor is cooled by a cooling oil in the housing. The apparatus includes a control unit configured to control the motor. The control unit has a temperature increase mode for heating the cooling oil with use of heat generated by a resistance of a coil provided in the stator.

An apparatus for controlling a motor having a housing in which a stator and a rotor are disposed. The motor is cooled by a cooling oil in the housing. The apparatus includes a control unit configured to control the motor. The control unit has a temperature increase mode for heating the cooling oil with use of heat generated by a resistance of a coil provided in the stator.

A method for operating power semiconductors arranged in converters, includes measuring with a temperature sensor a temperature of at least one of the power semiconductors, performing a comparison of the temperature of the at least one power semiconductor with a reference temperature and providing a result of the comparison; activating a pre-heating phase for preheating the power semiconductors as a function of the result; during the pre-heating phase, defining a pre-heating current; and impressing the pre-heating current into an electrical load.

A method for operating power semiconductors arranged in converters, includes measuring with a temperature sensor a temperature of at least one of the power semiconductors, performing a comparison of the temperature of the at least one power semiconductor with a reference temperature and providing a result of the comparison; activating a pre-heating phase for preheating the power semiconductors as a function of the result; during the pre-heating phase, defining a pre-heating current; and impressing the pre-heating current into an electrical load.