21In the 21st century, frequency conversion speed regulation has become the mainstream speed regulation scheme, which can be widely used in all walks of life stepless transmission. Especially with the increasingly extensive application of frequency converter in the field of industrial control, the use of frequency conversion motor is becoming more and more widespread, it can be said that because of the advantages of frequency conversion motor in frequency conversion control than ordinary motors, where we use frequency conversion motor is not difficult to see the figure of frequency conversion motor. In that wayFrequency conversion series motorIn terms of design, what are the highlights that can make it stand out from many motors? Senli Motor Xiaobian here to share his humble opinion:

Electromagnetic design:

For variable frequency motors, because the critical slip rate is inversely proportional to the power supply frequency, the critical slip rate can be close1Therefore, overload capacity and starting performance no longer need to be considered too much, and the key problem to be solved is how to improve the motor's ability to adapt to non-sine wave power. The way is generally as follows:

1) Reduce stator and rotor resistance as much as possible.

Reducing the stator resistance can reduce the fundamental copper consumption to make up for the increase of copper consumption caused by higher harmonics.

2)In order to suppress the higher harmonic in the current, it is necessary to increase the inductance of the motor appropriately. However, the skin effect of the larger rotor slot leakage resistance is also large, and the copper consumption of higher harmonic is also increased. Therefore, the size of the motor leakage reactance should take into account the rationality of the impedance matching in the whole speed regulation range.

3)The main magnetic circuit of the variable frequency motor is generally designed to be unsaturated, one is to consider the higher harmonics will deepen the saturation of the magnetic circuit, and the other is to consider the low frequency, in order to improve the output torque and appropriately increase the output voltage of the inverter.

Structure design:

In the structural design, it is mainly to consider the influence of non-sinusoidal power supply characteristics on the insulation structure, vibration, noise cooling mode and other aspects of the inverter motor, and generally pay attention to the following problems:

1)Insulation class, generallyFGrade or higher, strengthen the insulation to the ground and turn insulation strength, especially considering the ability of insulation to withstand impulse voltage.

2)For the vibration and noise problems of the motor, the rigidity of the motor components and the whole should be fully considered, and the natural frequency should be increased as much as possible to avoid resonance with each force wave.

Shengzhou Chaoli Electric Appliance Factory is committed to the development and manufacturing of high energy efficiency motor products, the main production of products are three-phase asynchronous motor, torque motor, brake motor, single-phase asynchronous motor, DC brushless motor, etc., founded the independent brand "Senli motor", but also can provide brand motor brand production. Products are widely used in textile machinery, plastic machinery, electric machinery, compression pump, food machinery, printing machinery, packaging machinery, environmental protection equipment and other industries.