Bidirectional dual-helix permanent magnet brushless motor with torque adaptive speed change

Abstract

Disclosed is a bidirectional dual-helix permanent magnet brushless motor with torque adaptive speed change. The bidirectional dual-helix permanent magnet brushless motor comprises a stator, a rotor, a shell, an end cover and other basic components, wherein the stator is provided with windings; the rotor is provided with a magnet; the bidirectional dual-helix permanent magnet brushless motor is characterized in that a set of dual-helix bidirectional displacement adjustment mechanism is arranged between the permanent magnet rotor and a motor shaft of the motor; and the dual-helix bidirectional displacement adjustment mechanism comprises the motor shaft with outer helix splines in the middle section, a spline ring with forward and backward helix splines of different rotary directions on the interior and the exterior respectively, a spline sleeve with helix splines in the interior, and springs used for measuring and adjusting torque. No matter the motor is in forward rotation or backward rotation, the set of the displacement adjustment mechanism can automatically detect electromagnetic torque; the rotor position can be changed according to change of a required load torque in real time; and magnetic flux of an air gap can be increased or decreased, so as to change electromagnetic parameters and to realize equipower speed regulation.

Description

technical field [0001] The invention belongs to motor technology, and in particular relates to a permanent magnet brushless motor capable of self-adaptive variable speed with torque variation. Background technique [0002] In recent years, permanent magnet brushless motors (EC motors), which are closely integrated with electronic technology, have been widely used due to their outstanding advantages such as high efficiency and energy saving. Technology develops rapidly. In particular, the research and development of technology for adjusting the air-gap magnetic field of permanent magnet motors to achieve equal power variable speed has become one of the hot spots. Among them, there are vector frequency conversion and direct torque control starting from electronic control, and there are magnetoelectric hybrid excitation, double rotor combined excitation, adjusting magnetic circuit and magnetic flux leakage and other schemes starting from motor. These known technical solutions...

AI Technical Summary

Problems solved by technology

These known technical solutions have their own characteristics. The electronic control method can realize complex and flexible program control, but it can only control the electrical parameters of the motor input such as frequency and phase waveforms from the outside. It mainly uses the direct axis current component Id to weaken the magnetic field, power The factor is not high, and a controller with a large power capacity is required. It is used in a permanent magnet synchronous motor (PMSM), and the cost is very high; the electronic control method is not suitable for a permanent magnet brushless motor (BLDC) with a small direct-axis inductance Ld; The electric compound excitation structure is complex; the dual-rotor combined excitation is typical of Hitachi patents, but its early centrifugal field weakening scheme lost too much efficiency, and the later publicized field weakening scheme using a spring screw mechanism needs to add other control actuators, which also requires 2 rotors, and the motor has only one rotation direction to adjust the speed

I previously disclosed in CN104979991 that the torque-adaptive variable-speed permanent magnet brushless motor uses a helical spline pair to realize torque-adaptive magnetization and speed regulation. Only one rotor is used, and the centrifugal mechanism or additional electromagnetic electronic control is omitted compared with the Hitachi solution. However, the single-screw mechanism limits the direction of rotation of the motor, and only one direction of rotation has the function of speed regulation. There is no problem in unidirectional drive applications such as two-wheeled electric vehicles and automatic variable-speed drilling machines.

However, some applications require the motor to be able to run forward and reverse, such as an electric wrench, and it is inconvenient to use this type of motor for vehicles that need to reverse at any time

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