Abstract : Variable frequency systems have the obvious advantage of speed regulation, and variable frequency speed control air conditioners utilizing variable frequency speed control technology have even better performance and significant energy-saving effects. Keywords : Variable frequency speed control technology; Inverter; Variable frequency air conditioner; Energy saving [b]1. Energy-saving principle of variable frequency air conditioner 1.1 Variable frequency speed control and energy saving[/b] The electromagnetic torque of an asynchronous motor is generated by the interaction between the stator main magnetic flux and the rotor. In reality, for an asynchronous motor, the speed of its rotating magnetic field n₀ is different from the rotor speed n, s = (n₀ - n) / n₀, which is called slip. Where n₀ = 60f/p, P is the number of pole pairs of the motor, and f is the power supply frequency, then the rotor speed n = 60f'(1-s)/p. When s does not change much, the asynchronous motor speed n is proportional to the stator power supply frequency f. Therefore, by continuously changing the stator power supply frequency, the speed of the asynchronous motor can be smoothly adjusted. In practical applications, to achieve good variable frequency speed regulation performance, the stator phase voltage is varied according to different patterns during frequency conversion. This can achieve constant torque and constant power to adapt to the requirements of different types of loads. The relationship between the power of fan and pump loads and their operating speed n is Q=k'n3. In the formula, k is the load power calculation coefficient, which is approximately 3 for fans and approximately 2 for pumps. Regardless of the speed regulation method used, the above formula can be used to calculate the load power. Let the maximum speed of the fan be n1, and the minimum speed determined according to actual needs be n2. Then the load power at different speeds is Q1=k'n13, Q2=k'n23. The maximum energy saving power of using variable frequency speed control (VFD) operation of an asynchronous motor compared to fixed speed operation is Qk = k'n1/3 - k'n2/3. In this formula, D = n1/n2 represents the speed range. As can be seen from the formula, the larger D is, the more significant the energy-saving effect of using VFD technology. [b][align=center]For more details, please click: Variable Frequency Air Conditioning Energy-Saving System[/align][/b]