A drive system comprises a DC-DC converter that is arranged to receive an input voltage from a battery having a nominal battery voltage. The DC-DC converter has a first mode of operation in which the DC-DC converter generates a regulated output voltage from the input voltage and supplies the regulated output voltage to a load, and a second mode of operation in which the DC-DC converter is by-passed such that the input voltage from the battery is supplied to the load. A controller is arranged to compare the input voltage to a threshold voltage that is less than the nominal battery voltage. The controller operates the DC-DC converter in the first mode when the input voltage is less than the threshold voltage, and operates the DC-DC converter otherwise.

A modular battery system provides propulsive power to the rotor system of an aircraft. The modular battery system includes an array of battery modules arranged in at least one stack. Each battery module includes a plurality of battery cells, a first side having positive and negative receptacles and a second side, that is opposite of the first side, having positive and negative plugs. The receptacles and plugs are configured such that adjacent battery modules in a side-by-side relationship are electrically coupled together via plug and receptacle connections and such that the battery modules are electrically coupled together in parallel. An interconnection electrically couples each stack of battery modules together via plug and receptacle connections with one of the battery modules in each stack such that the stacks of battery modules are electrically coupled together in parallel.

A method and system for operating a hybrid propulsion system, includes controllably providing a first power to a first bus and a first inverter, electrically coupling a first motor with a second inverter by way of a second bus, operably converting, by the second inverter, the first power received by the first inverter to a starting power adapted for starting the first motor, and increasing, by the second inverter, the starting power to match the first power received.

A tool for working a substrate, the tool having a stator and a working piston, which is intended to move relative to the stator along a working axis, also having a drive, which is intended to drive the working piston from a starting position along the working axis to the substrate, the drive comprising a first piston coil arranged on the working piston and a first stator coil arranged on the stator, and the first piston coil being intended to enter the first stator coil during a movement of the working piston relative to the stator along the working axis.

A remote control system for forward/reverse rotation of a fan includes a remote control and a forward-reverse rotation control unit. The remote control includes an operation module, and a first control module capable of outputting an operation signal which corresponds to an operation condition of the operation module. The operation signal can switch between a forward rotation mode and a reverse rotation mode to correspond to the operation condition of the operation module. The forward-reverse rotation control unit includes a double-pole relay that is controllable to switch between a first mode and a second mode and that is used to provide electric power to the fan, and a second control module that controls the double-pole relay to switch modes according to the operation signal, thereby making a rotational direction of the fan correspond to the operation of the operation module.

A method of monitoring the performance of a multi-phase electric motor (13), wherein the electric motor comprises a plurality of stator windings (7, 8, 9) connected in a wye configuration to form a wye point. The method comprises measuring an electrical characteristic of the wye point in a time domain; based upon the measured electrical characteristic of the wye point in the time domain, determining an electrical characteristic of the wye point in the frequency domain; and deriving data indicative of at least one parameter of the performance of the electric motor based upon the determined electrical characteristic of the wye-point in the frequency domain.

Disclosed herein are electric vehicles with various characteristics. For example, electric vehicles with at least two energy storage systems are described. As another example, electric vehicles with liquid temperature regulated battery packs are described. As yet another example, electric vehicles with high voltage battery limit optimization are disclosed. And, as another example, electric vehicles with dual-battery system charge management are described.

A permanent magnet motor is provided that produces variable magnetic flux. The motor may include two different types of permanent magnets with different coercivities. The magnetic state of one of the magnets may be altered during use. In one state, the effective magnetic flux of the motor is greater, and in another state, the effective magnetic flux of the motor is less.

A permanent magnet motor is provided that produces variable magnetic flux. The motor may include two different types of permanent magnets with different coercivities. The magnetic state of one of the magnets may be altered during use. In one state, the effective magnetic flux of the motor is greater, and in another state, the effective magnetic flux of the motor is less.

The disclosure relates to a hybrid-electrical drive system for an aircraft having two subsystems that are largely independent of each other. A stator winding of a common electrical machine is assigned to each of the subsystems such that both subsystems may be supplied with electrical energy from the common electrical machine. If a defect occurs in one of the subsystems, the drive system may be configured such that electrical energy from a battery of the non-defective subsystem may be transferred into the defective subsystem by utilizing the two stator winding systems.