The difference between the most popular synchronou

The difference between synchronous variable-frequency and asynchronous variable-frequency adjustable speed motors

asynchronous variable-frequency adjustable speed motors are derived from ordinary asynchronous motors. To adapt to the characteristics of inverter output power supply, the motor has made great changes in rotor slot type, insulation process, electromagnetic design verification, etc., especially the ventilation and heat dissipation of the motor. In general, it is attached with an independent forced cooling fan, In order to adapt to the efficient heat dissipation of the motor at low speed and reduce the wind friction consumption of the motor at high speed, the output value is expected to reach 21.8 billion yuan in 2018. The output of the frequency converter generally displays the output frequency of the power supply, and the speed output is displayed as the calculated value of the number of poles of the motor and the output frequency of the power supply, which is very different from the actual speed of the asynchronous motor. When using the general asynchronous variable frequency

motor, the slip rate of the asynchronous motor is determined by the manufacturing process of the motor, so its discreteness is very large, And the reason why the change of load directly wins the prize is largely that its manufacturing process affects the speed of the motor. To accurately control the speed of the motor, only the photoelectric encoder can be used for closed-loop control. When the single machine is controlled, the accuracy of the speed is determined by the pulse number of the encoder. When the multi machine is controlled, the speed of multiple motors cannot be strictly synchronized. This is the innate decision of asynchronous motor

the rotor of the synchronous variable-frequency speed regulation motor is embedded with permanent magnets. When the motor is instantly started, the motor turns into normal operation, and the stator rotating magnetic field drives the rotor embedded with permanent magnets to operate synchronously. At this time, the speed of the motor forms a strict corresponding relationship according to the number of poles of the motor and the input power frequency of the motor, and the speed is not affected by load and other factors. Similarly, the synchronous variable-frequency adjustable speed motor is also attached with an independent forced cooling fan to adapt to the efficient heat dissipation of the motor at low speed and reduce the wind friction consumption of the motor at high speed. Due to the strict correspondence between the speed of the motor and the power frequency, the speed accuracy of the motor mainly depends on the accuracy of the output power frequency of the frequency converter. The control system is simple. One frequency converter controls multiple motors to achieve the same speed of multiple motors, and there is no need for expensive optical encoder for closed-loop control

typ frequency conversion speed regulation permanent magnet synchronous motor has three advantages:

1. High efficiency and energy saving: compared with asynchronous frequency conversion speed regulation and cleaning and drying motor 1. Instrument and equipment management personnel must be familiar with the performance and use and operation procedures of the instruments and equipment in their charge, which is high efficiency and energy saving. Compared with the same specification, the efficiency of this series of motors is 3-10 percentage points higher than that of asynchronous variable frequency motors. Taking 1.5KW as the advantage, the efficiency difference between the two is nearly 7 percentage points

2. Accurate speed regulation: compared with asynchronous frequency conversion system, it can carry out accurate speed control without encoder

3. High power factor: it can not only reduce the consumption of reactive energy, but also reduce the capacity of the transformer