Abstract: A method and apparatus for controlling an electric aircraft. An apparatus comprises a motor, a power source, and a four-quadrant controller. The motor operates in four quadrants of operational space and operates in one of an accelerating state and a regenerative braking state. A total current flows through the motor. The power source is connected to the motor, and when the motor operates in the regenerative braking state, the total current flows through the power source. The power source has a maximum allowable current. The four-quadrant controller is programmed to identify a recharging parameter, brake the motor to initiate the regenerative braking state when the recharging parameter is present, recharge the power source with the total current during the regenerative braking state, and control a duty cycle of the motor such that the total current does not exceed the maximum allowable current during the regenerative braking state.

Abstract: A method and apparatus for controlling a motor. The motor comprises windings. A switch bridge comprising a plurality of switches is configured to couple a power source to the windings. A motor controller is configured to control the plurality of switches. An undesired condition identifier is configured to identify an undesired condition when the motor is providing power to the power source, wherein the undesired condition is defined with respect to a characteristic of the power source. An undesired condition reducer is configured to reduce the undesired condition in response to identifying the undesired condition by the undesired condition identifier.

Abstract: A method and apparatus for controlling a group of electric motors. A controller is configured to identify a group of switching frequencies for a desired signature for the group of electric motors. The controller is further configured to control switching of a current supplied to the group of electric motors with the group of switching frequencies for the desired signature identified.

Abstract: A method and apparatus for controlling an electric motor. A switching frequency meeting a desired operating condition is identified from information relating to operation of the electric motor. A switching of a current supplied to the electric motor with the switching frequency identified is controlled.

Abstract: A method for controlling an electric motor. A desired speed is identified for the electric motor during operation of the electric motor. A voltage is identified to cause the electric motor to turn at the desired speed. The voltage is applied to the electric motor and actively controlled during operation of the electric motor.

Abstract: A method and apparatus for controlling a motor. The motor comprises windings. A switch bridge comprising a plurality of switches is configured to couple a power source to the windings. A motor controller is configured to control the plurality of switches. An undesired condition identifier is configured to identify an undesired condition when the motor is providing power to the power source, wherein the undesired condition is defined with respect to a characteristic of the power source. An undesired condition reducer is configured to reduce the undesired condition in response to identifying the undesired condition by the undesired condition identifier.

Abstract: A method and apparatus for controlling operation of an electric motor. A controller is configured to identify a position of a disc relative to a plate with coils physically associated with the plate. The controller is further configured to control a current sent to the coils based on the position of a disc. The disc is configured to move such that a closest point between the disc and the plate changes along a periphery of the disc.

Abstract: A method and apparatus for controlling a motor. The motor comprises windings. A switch bridge comprising a plurality of switches is configured to couple a power source to the windings. A motor controller is configured to control the plurality of switches. An undesired condition identifier is configured to identify an undesired condition when the motor is providing power to the power source, wherein the undesired condition is defined with respect to a characteristic of the power source. An undesired condition reducer is configured to reduce the undesired condition in response to identifying the undesired condition by the undesired condition identifier.

Abstract: A method and apparatus for controlling an electric motor. A controller is configured to identify a start time for a signal based on a back electromotive force present in an electric motor during operation of the electric motor. The start time is for a position of a rotor relative to a group of coils. The controller is further configured to send the signal to the group of coils using the start time identified. An effect of the back electromotive force on the signal is reduced.

Abstract: A method and apparatus for controlling an electric aircraft is presented. An apparatus comprises a controller. The controller is configured to identify a state for an electric aircraft. The controller is further configured to identify a group of recharging parameters for a group of electric motors in an electric propulsion system. The electric propulsion system is configured to move the electric aircraft based on the state for the group of electric motors for the electric aircraft. The controller is still further configured to recharge a power source for the electric aircraft using the group of recharging parameters to control recharging of the power source with the group of electric motors when a recharge state is present for the electric aircraft.

Abstract: A method and apparatus for controlling operation of an electric motor. A controller is configured to identify a position of a disc relative to a plate with coils physically associated with the plate. The controller is further configured to control a current sent to the coils based on the position of a disc. The disc is configured to move such that a closest point between the disc and the plate changes along a periphery of the disc.

Abstract: A method and apparatus for controlling an electric motor. A controller is configured to identify a start time for a signal based on a back electromotive force present in an electric motor during operation of the electric motor. The start time is for a position of a rotor relative to a group of coils. The controller is further configured to send the signal to the group of coils using the start time identified. An effect of the back electromotive force on the signal is reduced.

Abstract: A method and apparatus for controlling a group of electric motors. A controller is configured to identify a group of switching frequencies for a desired signature for the group of electric motors. The controller is further configured to control switching of a current supplied to the group of electric motors with the group of switching frequencies for the desired signature identified.

Abstract: A method and apparatus for controlling a motor. The motor comprises windings. A switch bridge comprising a plurality of switches is configured to couple a power source to the windings. A motor controller is configured to control the plurality of switches. An undesired condition identifier is configured to identify an undesired condition when the motor is providing power to the power source, wherein the undesired condition is defined with respect to a characteristic of the power source. An undesired condition reducer is configured to reduce the undesired condition in response to identifying the undesired condition by the undesired condition identifier.

Abstract: A system for and method of providing investors with risk information regarding a portfolio, while protecting a strategy associated with the portfolio from public disclosure, is presented. The information allows investors to calculate a variety of risk statistics at virtually any level of granularity in analyzing divisions of the portfolio. The system and method also provide benefits for portfolio managers. Specifically, a portfolio manager may release detailed simulated returns, from which investors may calculate a variety of risk statistics, without revealing position information sufficient for the investors to reverse engineer a strategy associated with the portfolio.

Abstract: A method for controlling an electric motor. A desired speed is identified for the electric motor during operation of the electric motor. A voltage is identified to cause the electric motor to turn at the desired speed. The voltage is applied to the electric motor and actively controlled during operation of the electric motor.

Abstract: A system for and method of providing investors with risk information regarding a portfolio, while protecting a strategy associated with the portfolio from public disclosure, is presented. The information allows investors to calculate a variety of risk statistics at virtually any level of granularity in analyzing divisions of the portfolio. The system and method also provide benefits for portfolio managers. Specifically, a portfolio manager may release detailed simulated returns, from which investors may calculate a variety of risk statistics, without revealing position information sufficient for the investors to reverse engineer a strategy associated with the portfolio.

Abstract: A semiconductor component includes a base die and a secondary die stacked on and bonded to the base die. The base die includes conductive vias which form an internal signal transmission system for the component, and allow the circuit side of the secondary die to be bonded to the back side of the base die. The component also includes an array of terminal contacts on the circuit side of the base die in electrical communication with the conductive vias. The component can also include an encapsulant on the back side of the base die, which substantially encapsulates the secondary die, and a polymer layer on the circuit side of the base die which functions as a protective layer, a rigidifying member and a stencil for forming the terminal contacts. A method for fabricating the component includes the step of bonding singulated secondary dice to base dice on a base wafer, or bonding a secondary wafer to the base wafer, or bonding singulated secondary dice to singulated base dice.

Abstract: A method for fabricating a semiconductor component includes the steps of providing a substrate having a contact on a circuit side thereof, forming an opening from a backside of the substrate to the contact, forming a conductive via in the opening in electrical contact with a surface of the contact, and forming a second contact on the back side in electrical communication with the conductive via. The method can also include the steps of thinning the substrate from the backside, forming insulating layers on the circuit side and the backside, and forming a conductor and terminal contact on the circuit side in electrical communication with the conductive via. A semiconductor component includes the contact on the circuit side, the conductive via in electrical contact with the contact, and the second contact on the backside in electrical communication with the conductive via. The semiconductor component can also include the insulating layers, the conductor and the terminal contact.

Abstract: A semiconductor component includes a base die and a secondary die stacked on and bonded to the base die. The base die includes conductive vias which form an internal signal transmission system for the component, and allow the circuit side of the secondary die to be bonded to the back side of the base die. The component also includes an array of terminal contacts on the circuit side of the base die in electrical communication with the conductive vias. The component can also include an encapsulant on the back side of the base die, which substantially encapsulates the secondary die, and a polymer layer on the circuit side of the base die which functions as a protective layer, a rigidifying member and a stencil for forming the terminal contacts. A method for fabricating the component includes the step of bonding singulated secondary dice to base dice on a base wafer, or bonding a secondary wafer to the base wafer, or bonding singulated secondary dice to singulated base dice.