We all know that frequency converters can save energy when they are working. So, do you know the energy-saving principle of high-end frequency converters? Next, let Xinuoer explain the energy-saving principle of high-end frequency converters.
1. Variable Frequency Energy Saving: To ensure the reliability of our production, all kinds of production machinery are designed with a certain margin of safety when using power drives. Motors cannot operate under full load. Besides meeting the power drive requirements, excess torque increases active power consumption, resulting in energy waste. When the pressure is high, the motor speed can be reduced, saving energy while maintaining constant pressure. When the motor speed changes from N1 to N2, the change in the motor's shaft power (P) is as follows: P2/P1 = (N2/N1)³. Therefore, reducing the motor speed can achieve considerable energy savings.
2. Dynamic Energy Adjustment: Quickly adapts to load changes, supplying voltage with maximum efficiency. The variable frequency drive has a software-defined monitoring and control output function of 5000 times/second, ensuring the motor always operates at high efficiency.
3. Energy saving through the inverter's built-in V/F function: While ensuring the motor's output torque, the V/F curve can be automatically adjusted. This reduces the motor's output torque and lowers the input current, achieving energy saving.
4. Variable frequency drive's built-in soft start energy saving: When a motor starts at full voltage, it needs to draw seven times its rated current from the grid to achieve the required starting torque. This large starting current wastes electricity, significantly damages the grid's voltage fluctuations, and increases line and transformer losses. With soft start, the starting current can be reduced from 0 to the motor's rated current, minimizing the impact on the grid, saving on electricity costs, and reducing the impact of starting inertia on the high-speed rotation of the equipment, thus extending its service life.
5. Improve Power Factor and Save Energy: Electric motors generate torque through electromagnetic interaction between the stator and rotor windings. Due to their inductive reactance, the windings exhibit an inductive impedance characteristic relative to the power grid. This causes the motor to absorb a large amount of reactive power during operation, resulting in a low power factor. By using a variable frequency drive (VFD), the performance changes from AC to DC to AC. After rectification and filtering, the load characteristics change. The VFD exhibits a resistive impedance characteristic relative to the power grid, resulting in a high power factor and reduced reactive power loss.
Inverters achieve energy savings by reducing voltage under light loads. When driving a torque load, the speed doesn't change much, so even with voltage reduction, the energy savings are minimal. However, the situation is different in a fan environment. When a smaller airflow is needed, the motor speed decreases. We know that fan energy consumption is proportional to the 1.7th power of the speed, so the motor torque also decreases sharply, resulting in significant energy savings. If we were to use this in an oil well, the use of a braking resistor on the return stroke would waste a lot of energy, making it even more energy-intensive.
Of course, if the environment requires speed regulation, the energy-saving effect of the frequency converter is quite significant. In situations where speed regulation is not required, the frequency converter will not save electricity, but can only improve the power factor.
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