An electric drive system includes an energy storage system (ESS), a power conversion system, and an alternating current (AC) traction system. The ESS provides or receives electric power. The ESS includes a first energy storage unit and a second energy storage unit. The power conversion system is electrically coupled to the ESS for converting an input power to an output power. The AC traction system is electrically coupled to the power conversion system for converting the output power of the power conversion system to mechanical torques. The AC traction system includes a first AC drive device and a second AC drive device. An energy management system (EMS) is in electrical communication with the ESS, the AC traction system, and the power conversion system for providing control signals.

The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current I.sub.m of the induction motor at current stator frequency; selecting a smaller one of 0.5.Math.I.sub.m(1/+1) and (I.sub.m.sup.2+)/(I.sub.m+I.sub.m) as magnetizing current set point, in which is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.

The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current I.sub.m of the induction motor at current stator frequency; selecting a smaller one of 0.5.Math.I.sub.m(1/+1) and (I.sub.m.sup.2+)/(I.sub.m+I.sub.m) as magnetizing current set point, in which is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.

A motor driving method is applied to a motor with a rotor comprising a magnetic reluctance structure. The motor driving method comprises enabling the motor by an asynchronous driving method, controlling the motor by the asynchronous driving method according to a speed regulation command, detecting a rotor speed of the motor and determining whether the rotor speed is larger than a speed threshold, and when the rotor speed is larger than the speed threshold, controlling the motor by a synchronous driving method.

A motor driving method is applied to a motor with a rotor comprising a magnetic reluctance structure. The motor driving method comprises enabling the motor by an asynchronous driving method, controlling the motor by the asynchronous driving method according to a speed regulation command, detecting a rotor speed of the motor and determining whether the rotor speed is larger than a speed threshold, and when the rotor speed is larger than the speed threshold, controlling the motor by a synchronous driving method.

An inclinable measuring head for use in a coordinate measuring machine or in another measure system. The inclinable head has a support element and a probe holder rotatably linked to the support element by a spherical joint that is capable of being rotated about three independent axes. The measuring head further includes a position encoder providing relative orientation of the probe holder with respect to the support element, and an actuator arranged for orienting the probe holder relative to the support element.

An inclinable measuring head for use in a coordinate measuring machine or in another measure system. The inclinable head has a support element and a probe holder rotatably linked to the support element by a spherical joint that is capable of being rotated about three independent axes. The measuring head further includes a position encoder providing relative orientation of the probe holder with respect to the support element, and an actuator arranged for orienting the probe holder relative to the support element.

An electric drive system includes an energy storage system (ESS), a power conversion system, and an alternating current (AC) traction system. The ESS provides or receives electric power. The ESS includes a first energy storage unit and a second energy storage unit. The power conversion system is electrically coupled to the ESS for converting an input power to an output power. The AC traction system is electrically coupled to the power conversion system for converting the output power of the power conversion system to mechanical torques. The AC traction system includes a first AC drive device and a second AC drive device. An energy management system (EMS) is in electrical communication with the ESS, the AC traction system, and the power conversion system for providing control signals.

The rotary electrical machine having a homopolar structure includes a number Npe of electrical phases. The machine includes a juxtaposition, along the rotational axis of the rotary electrical machine, of at least one pair of armatures having a number of poles Np, placed on both sides of at least one inductive coil wound around the rotational axis, two adjacent armatures being angularly offset by any electrical angle s, preferably between 0 and 180/Npe, and at least one passive inductor of ferromagnetic material, separated from the armatures by an air gap. Either the armatures form the rotor, or the inductor and the other element form the stator.

The rotary electrical machine having a homopolar structure includes a number Npe of electrical phases. The machine includes a juxtaposition, along the rotational axis of the rotary electrical machine, of at least one pair of armatures having a number of poles Np, placed on both sides of at least one inductive coil wound around the rotational axis, two adjacent armatures being angularly offset by any electrical angle s, preferably between 0 and 180/Npe, and at least one passive inductor of ferromagnetic material, separated from the armatures by an air gap. Either the armatures form the rotor, or the inductor and the other element form the stator.