Working principles of high-efficiency energy-saving motors and variable-frequency energy-saving motors

Working principles of high-efficiency energy-saving motors and variable-frequency energy-saving motors

Working principle of frequency converter: The frequency converter we use mainly adopts AC-DC-AC mode, first converting the industrial frequency AC power into DC power through a rectifier, and then converting the DC power into AC power with controllable frequency and voltage to supply the motor. The circuit of the frequency converter generally consists of four parts: rectification, intermediate DC link, inversion and control.

The rectifier part is a three-phase bridge uncontrolled rectifier, the inverter part is an IGBT three-phase bridge inverter, and the output is a PWM waveform. The intermediate DC link is for filtering, DC energy storage and reactive power buffering.

Working principle of high-efficiency and energy-saving motor: Adopt new motor design, new technology and new materials to improve output efficiency by reducing the loss of electromagnetic energy, thermal energy and mechanical energy.

Advantages: 1. Direct start, can fully replace asynchronous motor;

2. Rare earth permanent magnet high-efficiency energy-saving motor can save more than 3℅ of electric energy compared with ordinary motor;

3. The motor power factor is generally higher than 0.90, which improves the quality factor of the power grid and does not require a power factor compensator;

4. The motor current is small, which saves power transmission and distribution capacity and extends the overall operating life of the system;

5. Adding a driver can achieve soft start, soft stop and stepless speed regulation, and the power saving effect is further improved.

The difference between high-efficiency energy-saving motors and variable frequency energy-saving motors

1. High-efficiency and energy-saving motors improve the operating efficiency of the motor itself through manufacturing processes

2. Frequency conversion energy saving means saving electricity by adjusting the motor speed. The energy conversion ratio is not improved but reduced because of the increased loss of the inverter.

3. Frequency conversion speed regulation is mainly used in situations where the load changes, and the energy saving effect is very obvious. Its energy saving principle is simply to change the frequency according to the needs, and then change the output power.

4. For occasions with stable loads, that is, occasions where speed regulation is not required, the use of a frequency converter will reduce overall efficiency and waste electricity.

5. In situations where the load changes greatly, both can save electricity, but variable frequency speed regulation can save a much greater proportion of electricity. Compared with ordinary motors of the same power, high-efficiency energy-saving motors can generally only increase energy saving by a few percentage points.

6. The motor powered by the frequency converter is called a variable frequency motor, which is different from the ordinary motor. The frequency converter directly drives the ordinary motor, which is harmful to the motor.

7. The energy-saving principles of the two are different, and both can be used at the same time. Both technologies need to be vigorously developed and promoted.