We often say that three-phase permanent magnet synchronous motors are more energy-efficient than asynchronous motors. Why do we say this? What are the advantages of permanent magnet synchronous motors over asynchronous motors in terms of energy efficiency? Let's discuss in detail the issue of three-phase permanent magnet synchronous motors being more energy-efficient than asynchronous motors.

1. The no-load current of asynchronous motors is about one-third of the rated motor current, while the no-load current of permanent magnet synchronous motors is only one-tenth of the rated current. When the motor is lightly loaded, the current is small, which saves energy.

2. Asynchronous motors require the stator to provide rotor induction current to generate a magnetic field, while the rotor of permanent magnet synchronous motors is embedded with rare earth permanent magnets and does not require current, eliminating the need for rotor power supply.

3. Due to lower losses, the equipment size and power required for cooling the permanent magnet synchronous motor are smaller.

4. The rated energy efficiency of asynchronous motors decreases proportionally under conditions of reduced load and speed, while the permanent magnet synchronous motor basically maintains its rated energy efficiency standard when load and speed change.