Controllable-flux permanent magnet synchronous motor and control system for electric vehicle

Abstract

The invention discloses a controllable-flux permanent magnet synchronous motor and a control system for an electric vehicle. A permanent magnet rotor of the motor is in a built-in mixed type rotor magnetic path structure, an Nd-Fe-B permanent magnet and an Al-Ni-Co permanent magnet of the rotor iron core are arranged according to the matrix way of Halbach, a certain gap is arranged between each electrode of the rotor, and the Nd-Fe-B permanent magnet and the Al-Ni-Co permanent magnet are embedded in silicon steel sheets; the Nd-Fe-B permanent magnet is used as the main magnetic flux of the motor rotor, and the magnetizing direction of the Nd-Fe-B permanent magnet is diagonally magnetizing; and the Al-Ni-Co permanent magnet is magnetized radially, and the magnetizing direction is controlled by direct-axis current Id of the control system to be used as the adjusting magnetic flux of the motor rotor. The controllable-flux permanent magnet synchronous motor and the control system for the electric vehicle have the advantages that the magnetic flux state of the motor rotor is changed through applying a direct-axis current Id with controllable amplitude by the control system, so that the magnetic flux provided by the rotor to the stator is minimal; three-phase lines of the motor are short-circuits, the back electromotive force of the motor approaches to zero, and the braking torque is extremely low, thereby guaranteeing the electric safety and torque safety of a vehicle under the state that the system stays in failure.

Description

technical field [0001] The invention belongs to new energy vehicle motor and drive technology, in particular to a controllable magnetic flux permanent magnet synchronous motor and a control system for electric vehicles. Background technique [0002] Due to the high efficiency and good torque characteristics of permanent magnet motors, most electric vehicles, especially electric cars, use permanent magnet motors. The permanent magnetic material NdFeB has high residual magnetic induction intensity, large magnetic induction coercive force, and high maximum magnetic energy product. It is the permanent magnetic material with the highest magnetic performance at present. Permanent magnet motors for electric vehicles generally use a single NdFeB permanent magnet as the permanent magnet material. In order to take into account the inverter capacity of the motor control system and the motor's field-weakening speed expansion, the winding design of the permanent magnet motor for vehicle...

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Problems solved by technology

In recent years, some domestic scholars have also conducted some research on the controllable flux permanent magnet synchronous motor, but most of them stay at the prototype stage and have no real products; and the focus of these researches is often on the field weakening speed expansion and efficiency issues , rarely involved in the field of electric vehicle safety

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