Tula eTechnology, Inc.

A variety of methods, controllers, and electric machine systems are described that facilitate pulsed control of multiple electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and a second output level that is lower than the first output level. The output levels are selected such that at least one of the electric machines and a system that includes the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the second output level is zero torque.

Pulsed control of electric motors, and more particularly, to selectively adjusting one or more of a pulsing frequency, an amplitude of the pulses and/or a duty cycle of the pulses for reducing Noise, Vibration and Harshness (NVH) while maintaining high levels of operating efficiency.

Modulated pulse control of electric machines to deliver a desired output in a more energy efficient manner by either (a) operating the electric machine in a continuous mode when a requested torque demand is greater than the peak efficiency torque of the electric machine or (b) in a pulsed modulation mode when the requested torque demand is less than the peak efficiency torque of the electric machine. When operating in the pulsed modulation mode, the inverter may be deactivated to further improve the system efficiency when field weakening is not required to mitigate or eliminate generation of a retarding torque in situations when Back Electromagnetic Force (BEMF) exceeds a supply voltage for the inverter of the machine.

A boost circuit and method is described for supplying a boost voltage to a rotor of the electric machine, just as the electric machine is pulsed on, the boost voltage aids the rotor in quickly overcoming its start-up inductance, rapidly turn on the rotor. As a result, much faster transition times are realized each time the electric machine transitions from the off state to the on state at the start of a pulse. By reducing the transition time, the overall efficiency of the electric machine is significantly improved.

Methods, controllers and electric machine systems are described that facilitate pulsed control of electric machines (e.g., electric motors and generators) to improve the machine's energy conversion efficiency. Under selected operating conditions, the electric machine is intermittently driven (pulsed). The pulsed operation causes the output of the electric machine to alternate between a first output level and an off state. The output levels are selected such that the electric machine has a higher energy conversion efficiency during the pulsed operation than the electric machine would have when operated at a third output level that would be required to drive the electric machine in a continuous manner to deliver the desired output. In some embodiments, the power converter it turned off during at least portions of the time that the electric machine is pulsed off.

Various boost circuits that are used to improve or reduce the time needed to transition an electric machine from an off-state to an on-state at the start of a next pulse during pulsed controlled operation. With these various boost circuits, the naturally generated Back Electromotive Force or “BEMF” that is induced when an electrical machine transitions from the on state to the off state at the end of an on pulse is harvested, rectified, and stored on a storage device. The harvested energy is then made available to the electric machine as a “boost” voltage at the onset of the next on pulse, resulting in a reduced transition time from the off-state to the on-state.

An electric machine is provided. A power converter is coupled between a power supply and a wound field synchronous machine. The power converter is arranged to provide a pulsed operation by providing a pulsed DC current to field windings of the wound field synchronous machine.

Pulsed control of electric motors, and more particularly, to selectively adjusting one or more of a pulsing frequency, an amplitude of the pulses and/or a duty cycle of the pulses for reducing Noise, Vibration and Harshness (NVH).

A control system for an electric machine, wherein the electric machine has a maximum bus value (V bus ) is provided. The control system is configured to determine a feedforward vector (V FF ), determine a feedback vector (V FB ), compare a magnitude of a sum of the feedforward vector and feedback vector (|V FF +V FB |) and the maximum bus value (V bus ), when |V FF +V FB |≤V bus providing a control vector of V FF +V FB to the electric machine, and when |V FF +V FB |>V bus providing a control vector of V FF +k(V FB ) to the electric machine, where k is a scalar value between 0 and 1 inclusive where |V FF +k(V FB )|=V bus .

An electric machine is provided. A transformer comprises a magnetic coupling. A wound field synchronous machine comprises a rotor winding, a secondary circuit of the transformer electrically connected to the rotor winding, and a stator winding. The secondary circuit comprises a secondary winding, a rectifier electrically, a switch for switching voltage between the rotor winding and the rectifier in a first direction, and an energy storage arranged to store energy provided by the rectifier and the rotor winding and provide a voltage to the rotor winding in a second direction. A power converter is coupled between the power supply and the wound field synchronous machine. The power converter comprises a stator winding power supply arranged to provide multiple phase AC excitation to the stator winding and a primary circuit of the transformer comprising a primary winding arranged to provide AC power to the primary winding.