A propulsion system for an unmanned underwater vehicle includes a turbine engine, a generator mechanically coupled to an output shaft of the turbine engine, an electrical motor mechanically decoupled from the turbine engine and electrically coupled to the generator via a power bus architecture, and a propulsor mechanically coupled to a rotational output of the electrical motor. The power bus architecture includes a pair of AC buses and a DC bus.

A propulsion system for an unmanned underwater vehicle includes a turbine engine having a rotational output, an electrical generator mechanically connected to the rotational output and electrically connected to an Alternating Current (AC) power bus. A magnitude of an AC output of the electrical generator is independent of rotational speed of the rotational input. An electrical motor connected to the AC power bus, and includes a mechanical output.

When the voltage value of the capacitor included in the PCU is equal to or higher than a predetermined value, the vehicle power supply device turns on both the positive switching element and the negative switching element corresponding to one of a plurality of resistors so as to activate the one resistor connected to the initially disabled PCU. In addition, the vehicle power supply device turns on both the positive switching element and the negative switching element corresponding the other one of the resistors so as to deactivate the one resistor and activate the other one resistor based on a predetermined condition.

When the voltage value of the capacitor included in the PCU is equal to or higher than a predetermined value, the vehicle power supply device turns on both the positive switching element and the negative switching element corresponding to one of a plurality of resistors so as to activate the one resistor connected to the initially disabled PCU. In addition, the vehicle power supply device turns on both the positive switching element and the negative switching element corresponding the other one of the resistors so as to deactivate the one resistor and activate the other one resistor based on a predetermined condition.

A hybrid drive train for a self propelled power trowel includes a frame having a centerline from front to rear, an engine-generator set, a pair of rotors with trowel blades tiltably connected to the frame and positioned to support the frame above a concrete surface being finished, electric motors for driving the rotors, means for tilting each rotor toward and away from the centerline, and means for tilting a rotor fore and aft, parallel to the centerline. A rectifier and inverter in series at the engine-generator output allows engine speed to be regulated by a capacitor bank, and usage of highly efficient brushless AC synchronous motors to drive the rotors. A rechargeable battery may be connected in parallel with the capacitor bank.

A hybrid vehicle includes an isolation switch disposed between a first bus that is electrically coupled to a starter for an engine and a second bus that is electrically coupled to a power converter and accessory loads. The hybrid vehicle includes a controller programmed to normally command the switch closed, and, in response to expiration of a predetermined time interval without starting the engine, command the switch to open for a predetermined duration to perform diagnostics on the isolation switch.

An electromagnetic piston engine is characterized by an engine block containing at least one cylinder, within which at least one electromagnet is positions. Within the cylinder, the present invention may also provide for a piston attached to a camshaft, the piston having a magnetic end element fixably attached to its terminus. By means of a power source, the present invention may energize the electromagnet(s), which may provide for an electromagnetic force to be generated within the cylinder and which may act on the magnetic end element(s). The effect of this electromagnetic force may be to either attract or repel, or alternatingly attract and repel, the magnetic end element, thereby moving the piston back and forth within the cylinder, rotating the camshaft and powering a vehicle.

Systems and method for an electrical system on an aircraft are provided. In example embodiments, the electrical system can be for an aircraft having a turbine engine. The turbine engine having a high pressure (HP) spool and a low pressure (LP) spool. The HP spool can be configured to drive a first generator to provide a first electrical output. The LP spool can be configured to drive a second generator to provide a second electrical output. The first generator and the second generator can be coupled to an electrical power distribution bus that provides electrical power to a load. A hybrid electric propulsion system and a secondary aircraft systems bus can both be coupled to the electrical power distribution bus. The electrical system can further include a control system configured to allocate power among the first generator, the second generator, and the hybrid electric propulsion system, and the secondary aircraft systems bus.

A vehicle system in a hybrid vehicle comprises a controller configured to generate for output a modulated voltage to a direct current capacitor to prevent voltage spikes on the capacitor in response to receiving a reference current via a direct current voltage clamping control block that outputs a reference current in response to a difference between a feedback voltage and a reference voltage exceeding a threshold.

A vehicle includes a power source, a controller, a converter configured to receive a first voltage from the power source and to convert the first voltage to a second voltage, an auxiliary inverter system electrically coupled to an output of the converter and to an accessory having an electric motor, the auxiliary inverter system configured to convert the second voltage received from the converter for powering the electric motor, and a first communication link between the controller and the auxiliary inverter system. The auxiliary inverter system is further configured, responsive to interruption of the first communication link, to control a speed of the electric motor based on a level of the second voltage.