Motor torque ripple

Electromagnetic torque ripple is due to the interaction between stator current and rotor magnetic

field and the torque ripple, it with the current waveform, the back emf waveform, the air gap

magnetic flux density electric fan motor parts is directly related to the distribution. Ideally, the stator current for the square wave, the back emf waveform as the trapezoidal wave, flat top width is 120 ° electrical point of view, the electromagnetic torque is constant value. Permanent magnet brushless perkins diesel generator dc motor due to its simple structure, high reliability, low speed high torque characteristics and has been more and more widely used, especially in recent years has been widely applied in the electric bicycle. Due to 4/7.5 Y132M - KW ac asynchronous motor bike is People's Daily transport, so people start the stability of the vehicle, such as noise www.facebook.com/dongfeng.motor indicators put forward higher requirements. Most of the existing electric motor using permanent magnet brushless dc motor, motor iron core of straight groove structure, winding for three-phase star connection, in two general inverter on state. Because of its high straight slot motor torque fluctuation at work, so we must optimize the motor structure and coordination with the optimized design of the controller can obtain satisfactory results. In this paper, how to design the ultra- quiet permanent magnet brushless dc motor controller for some discussions. The actual motor, the design and manufacture of reasons, may make the back emf waveform is not a trapezoidal wave, or wave crest width is 120 ° electrical point of view, this will cause the motor torque ripple.

In fact, it's not difficult to find such a MCU, such as the special motor control chip XC866 infineon, on-chip programmable control chip CY8C24533 with CYPRESS, etc. XC866 A/D conversion speed can reach 2 within us, plus program execution time, an A/D conversion to the total time within the eight of us, at that time interval complete enough to determine whether the current compensation. CY8C24533 CYPRESS is specifically designed for motor control development with high speed A/D chip, within its SAR8 conversion speed can reach 3 us,magnet generat orcombined with the automatic alignment trigger mode, A/D can be triggered at any time in the PWM current A/D sampling, it is also easy to realize the precise control of the current. Permanent magnet brushless motor with the electromagnetic factors, the influence of tooth, current commutation, the armature reaction will produce strong pulsating torque. In design Y180L - 4/22 kw three-phase asynchronous motor and the corresponding control system should be seriously considered, take measures to avoid excessive torque ripple. Due to the low speed high load running, the motor rotation of the electric potential is very small, in order to make the motor phase current shall not exceed the allowed maximum, PWM duty cycle is generally small, which makes the phase after the new phase winding current rising slowly. Adopting AOS (ten thousand) semiconductor production AOT460 MOSFET simulation. PSPICE software model of MOSFET using level3 level. In order to make the

commutation current rise rapidly, we can make the change after phase PWM duty ratio of 100% to

compensate for current, until the current up to the front of the commutation of current value, so

that we can make the change of phase current fluctuations in as little as possible, as far as

possible short time. As a result of the existence of groove teeth of the stator core, makes the

permanent magnet with the corresponding armature surface uneven air gap permeance, when the rotor rotates, made in a state of magnetic, magnetic circuit magnetic resistance change, that cause torque ripple. The cogging torque ripple caused by the rotor is magnetic fields interact to produce, has

nothing to do with the stator current. Thus restrained due to the cogging torque ripple mainly

focused on the optimization of motor design, such as chute.