A process for controlling an electric motor includes providing a functional relationship, which associates a first and a second quantity , indicative of a torque delivered by the electric motor and of the supply voltage respectively, with a speed parameter of the electric motor, determining a pair of values of the first and of the second quantity , determining a value of a third quantity indicative of an output speed of the electric motor, determining a value of the speed parameter corresponding to the pair of values determined through the functional relationship, determining a value of a fourth quantity indicative of a difference between the value of the speed parameter and the value of the third quantity, determining a target value for the first quantity as a function of the value of the fourth quantity, and controlling the electric motor according to the determined target value.

A mobile surface maintenance machine embodiment includes a mobile body, a solution tank for containing a cleaning fluid, wheels for supporting the mobile body, a maintenance tool(s), an output channel, an electric power source, a first electric motor, and a pressure washer. The pressure washer includes a spray wand, a pressure pump, and a second electric motor. The pressure pump is fluidly coupled to the spray wand and to the solution tank. The pressure pump is configured to pressurize the cleaning fluid supplied to the spray wand. The second electric motor is operatively coupled to and configured to drive the pressure pump. The second electric motor is configured to receive electric power from the electric power source and is commonly powered by the electric power source that provides power to the first electric motor. The second electric motor is separate from the first electric motor.

A direct current traction motor control system includes plural motors of with each of the motors configured to be coupled with a different axle of a vehicle and to rotate the axle to propel the vehicle. The motors are coupled with a DC bus and configured to receive DC via the DC bus to power the motors. The system also includes plural switch assemblies with each of the switch assemblies having an H-bridge circuit coupled with a different motor of the motors to control rotation of the motor. The system includes a controller configured to communicate control signals to the switch assemblies to individually control the H-bridge circuits to control one or more of torques output by the motors or rotation directions of the motors.

An exemplary motor driving system includes a power source, a driving circuit, a controller, a motor, and a protection circuit. The driving circuit including at least one switching device coupled with the power source. The motor includes a plurality of windings. The motor is coupled with the driving circuit and driven by the driving circuit. The controller is configured to provide first switch signals to the at least one switching device of the driving circuit in a normal mode. The protection circuit is coupled with the controller, and configured to generate second switch signals based at least in part on a fault signal in a fault mode and provide the second switch signals to the at least one switching device of the driving circuit so as to reconstruct circuit loops between the driving circuit and the plurality of windings. A method for operating the motor driving system is also described.

A system for maintaining battery cycle life for motorized battery-powered electric vehicles. Current battery-powered electric vehicles such as automobiles and trucks suffer from short cycle life of their batteries, meaning that these vehicles' batteries will become unusable well before reaching the normal useful life of combustion engine powered vehicles. Owners of vehicles using my system will enjoy vehicles with acceptable ranges, acquisition and operating costs, yet will enjoy battery lifetimes as long or as longer than the useful life of combustion engine vehicles.

A drive control device includes a self-excited generator to generate and output electric power by being driven by an internal combustion engine, and a separately excited generator to generate and output electric power by being driven by the internal combustion engine when the separately excited generator is in an excited state. The drive control device further includes a first power converter to convert electric power fed from the separately excited generator via primary terminals into DC power and output the DC power via secondary terminals or to convert DC power fed via the secondary terminals into electric power to be fed to the separately excited generator and output the electric power via the primary terminals, and a capacitor connected between the secondary terminals of the first power converter.

A direct current traction motor control system includes plural motors of with each of the motors configured to be coupled with a different axle of a vehicle and to rotate the axle to propel the vehicle. The motors are coupled with a DC bus and configured to receive DC via the DC bus to power the motors. The system also includes plural switch assemblies with each of the switch assemblies having an H-bridge circuit coupled with a different motor of the motors to control rotation of the motor. The system includes a controller configured to communicate control signals to the switch assemblies to individually control the H-bridge circuits to control one or more of torques output by the motors or rotation directions of the motors.

A hybrid electric aircraft propulsion system and method of operation are described. The system comprises a thermal engine, a generator coupled to the thermal engine, a first electric propulsor operatively connected to the generator to receive alternating current (AC) electric power therefrom, a second electric propulsor, a generator inverter operatively connected to the generator to convert AC electric power to direct current (DC) electric power, and a first motor inverter operatively connected to the generator inverter and selectively connected to one of the first electric propulsor and the second electric propulsor and configured to receive the DC electric power and provide the first electric propulsor and the second electric propulsor with AC electric power, respectively.

A drive system for a vehicle having a rear drive assembly powered by a first power source, a front drive assembly in selective electrical communication with a second power source, a selector switch to selectively permit or prevent electrical communication between the front drive assembly and the second power source, and an output capacity sensor to detect an output of the first power source, where the rear drive assembly drives the vehicle when the selector switch is in a first position and both the rear and front drive assemblies drive the vehicle when the selector switch is in a second position and the output capacity sensor detects that the output of the first power source meets a threshold output.

There is described a method and system for operating a hybrid electric aircraft propulsion system. The method comprises modulating AC electric power applied to a first electric propulsor or a second electric propulsor from at least one motor inverter to synchronize the frequency of the first electric propulsor or the second electric propulsor with the frequency of a generator.