A method for determining rotor characteristic of an alternating current (AC) electrical machine includes obtaining a reference voltage signal, one or more phase currents, and rotor data. The method includes determining orthogonal components of an extended back electromotive force (BEMF) model of the AC electrical machine based on the reference voltage signal, the one or more phase current characteristics, and the rotor data. The method includes determining a product of the orthogonal components of the extended BEMF model. The method includes determining a squared-magnitude of the orthogonal components of the extended BEMF mode. The method includes determining the rotor characteristic of the AC electrical machine based on the product of the orthogonal components and the squared-magnitude of the orthogonal components.

A system may include a variable frequency independent speed (VFIS) motor-generator. The system may further include a first power conditioner coupled to a set of stator windings of the VFIS motor-generator and a second power conditioner, distinct from the first power conditioner, coupled to a set of primary windings of a high-frequency transformer, where a set of secondary windings of the high-frequency transformer are coupled to a set of rotor windings of the VFIS motor-generator. A method may include providing a first power signal at the set of stator windings. The method may further include generating a second power signal at the second power conditioner for driving the set of rotor windings, where a shaft speed of the VFIS motor-generator is based on a difference between a first frequency of the first power signal and a second frequency of the second power signal.

A method for determining rotor characteristic of an alternating current (AC) electrical machine includes obtaining a reference voltage signal, one or more phase currents, and rotor data. The method includes determining orthogonal components of an extended back electromotive force (BEMF) model of the AC electrical machine based on the reference voltage signal, the one or more phase current characteristics, and the rotor data. The method includes determining a product of the orthogonal components of the extended BEMF model. The method includes determining a squared-magnitude of the orthogonal components of the extended BEMF mode. The method includes determining the rotor characteristic of the AC electrical machine based on the product of the orthogonal components and the squared-magnitude of the orthogonal components.

A method for determining rotor characteristic of an alternating current (AC) electrical machine includes obtaining a reference voltage signal, one or more phase currents, and rotor data. The method includes determining orthogonal components of an extended back electromotive force (BEMF) model of the AC electrical machine based on the reference voltage signal, the one or more phase current characteristics, and the rotor data. The method includes determining a product of the orthogonal components of the extended BEMF model. The method includes determining a squared-magnitude of the orthogonal components of the extended BEMF mode. The method includes determining the rotor characteristic of the AC electrical machine based on the product of the orthogonal components and the squared-magnitude of the orthogonal components.

A fire suppression system includes a motor and a foam pump. The foam pump is driven by the motor to inject one or more chemical additives from an off-board additive container into a discharge conduit. A bypass valve is in fluid communication with the output of the foam pump. One or more sensors are configured to measure at least one operating condition of the foam pump. A controller is in communication with the one or more sensors and is operatively connected to the bypass valve. The controller is configured to determine, based on data received from the one or more sensors regarding the at least one operating condition of the foam pump, whether the foam pump is experiencing a loss of prime, and to open the bypass valve in response. The motor may also selectively operate in one of two modes depending on the rotational speed and torque required.

A fire suppression system includes a motor and a foam pump. The foam pump is driven by the motor to inject one or more chemical additives from an off-board additive container into a discharge conduit. A bypass valve is in fluid communication with the output of the foam pump. One or more sensors are configured to measure at least one operating condition of the foam pump. A controller is in communication with the one or more sensors and is operatively connected to the bypass valve. The controller is configured to determine, based on data received from the one or more sensors regarding the at least one operating condition of the foam pump, whether the foam pump is experiencing a loss of prime, and to open the bypass valve in response. The motor may also selectively operate in one of two modes depending on the rotational speed and torque required.

A rotary electric machine is equipped with a stator and a rotor. The rotor has a d-axis magnetic circuit that is produced by a magnetomotive force of a field winding, and magnet magnetic circuits that are produced by a magnetic force of permanent magnets. The d-axis magnetic circuit and a q-axis magnetic circuit have at least a part thereof that is common to both. The permeance of the d-axis magnetic circuit is smaller than the permeance of the q-axis magnetic circuit, when a load is being applied to the rotor. A control apparatus of the rotary electric machine has a switching circuit that controls the field current in the field winding, and a control section that makes the switching frequency of the switching circuit become higher when the field current is above a threshold value than when the field current is less than or equal to the threshold value.

A kinetic energy recovery system with flywheel includes a flywheel doubly-fed electric machine, an electric motor, a drive circuit and a controller. The flywheel doubly-fed electric machine has a primary side coil and a secondary side coil. The electric motor has a phase coil connected in series with the primary side coil. The drive circuit has an AC/DC circuit and a DC/AC circuit, wherein the AC end of the AC/DC circuit is coupled to the primary side coil; the AC end of the DC/AC circuit is coupled to the secondary side coil. The controller is configured to manipulate a frequency and a phase of output voltage and output current of the secondary side coil, thereby controlling the frequency and phase of a voltage and a current output from the primary side coil, thereby recovering a kinetic energy of the electric motor or providing the kinetic energy to the electric motor.

A kinetic energy recovery system with flywheel includes a flywheel doubly-fed electric machine, an electric motor, a drive circuit and a controller. The flywheel doubly-fed electric machine has a primary side coil and a secondary side coil. The electric motor has a phase coil connected in series with the primary side coil. The drive circuit has an AC/DC circuit and a DC/AC circuit, wherein the AC end of the AC/DC circuit is coupled to the primary side coil; the AC end of the DC/AC circuit is coupled to the secondary side coil. The controller is configured to manipulate a frequency and a phase of output voltage and output current of the secondary side coil, thereby controlling the frequency and phase of a voltage and a current output from the primary side coil, thereby recovering a kinetic energy of the electric motor or providing the kinetic energy to the electric motor.

A kinetic energy recovery system with flywheel includes a flywheel doubly-fed electric machine, an electric motor, a drive circuit and a controller. The flywheel doubly-fed electric machine has a primary side coil and a secondary side coil. The electric motor has a phase coil connected in series with the primary side coil. The drive circuit has an AC/DC circuit and a DC/AC circuit, wherein the AC end of the AC/DC circuit is coupled to the primary side coil; the AC end of the DC/AC circuit is coupled to the secondary side coil. The controller is configured to manipulate a frequency and a phase of output voltage and output current of the secondary side coil, thereby controlling the frequency and phase of a voltage and a current output from the primary side coil, thereby recovering a kinetic energy of the electric motor or providing the kinetic energy to the electric motor.