Permanent magnet synchronous motor AC asynchronous Motors advantages over what?

1, high efficiency, more power:

A, due to the magnetic field of the permanent magnet synchronous motor is generated by permanent magnets, so as to avoid through the excitation current to generate a magnetic field which causes loss of excitation (copper losses);

B, curve characteristics of permanent magnet synchronous motor efficiency than asynchronous motor, its efficiency in light load value is much higher, this is a permanent magnet synchronous motor in terms of energy saving, one of the biggest advantages of asynchronous motor in comparison. Because usually motor in drive load Shi, rarely situation is in full power run, this is because: while user in motor selection Shi, General is according to load of limit workers condition to determine motor power, and limit workers condition appeared of opportunities is rarely of, while, for prevent in exception workers condition Shi burn loss motor, user also will further to motor of power left Yu volume; on the, designers in design motor Shi, for guarantee motor of reliability, usually will in user requirements of power based Shang, further left must of power Yu volume, Resulting in the actual running of the motor 90% is operating at the rated power of the 70%, especially in driving fans or pumps, which cause the motors are usually working at light load. Asynchronous motor, the light load efficiency is very low, and permanent magnet synchronous motor at light load, can still keep high efficiency, its efficiency than asynchronous motor 20%.

C, as the permanent magnet synchronous motor with high power factor, compared to smaller asynchronous motor the motor current, motor stator copper losses accordingly smaller, efficiency is higher.

D, high system efficiency: permanent magnet motor parameters, especially power factor, not under the influence of motor pole number, thus facilitating designed with Multipole Motors (such as more than 100 poles), traditional gearbox to drive the load motor is needed, you can create directly drived by permanent magnet synchronous motor direct drive system, eliminating the gearbox, improved transmission efficiency.

2, high power factor:

At design-time as the permanent magnet synchronous motor, power factor can be adjusted, can even design success factor is equal to 1, and it has nothing to do with the pole. Along with the increase of the number of asynchronous motor, excitation characteristics of asynchronous Motors itself, inevitably leads to increasingly low power factor, such as pole 8 pole motors, which usually is about 0.85 power factor, the greater the number of corresponding lower the power factor. Even the highest factor of 2 pole motor, can hardly achieve its power factor 0.95. Motor power factor and there are several good


A, high power factor, motor current, motor stator copper losses decrease, more energy-efficient;

B, high power factor, motor power, such as inverters, transformers, capacity can be lower, and other auxiliary facilities such as switches, cables and other specifications can be smaller, lower system costs.

C, due to the permanent magnet synchronous motor power factor level without the limitation of motor pole number, in the case of motor system allows, the number of poles of the motor can be designed better, smaller volume of the corresponding motor can do, the direct material cost of the motor lower.

3, the structure is simple and flexible:

A,, and due to asynchronous motor rotor Shang need installation guide article, and end ring or rotor winding, greatly limit has asynchronous motor structure of flexibility, and PM synchronization motor rotor structure design more flexible, as on railway traction motor, can will motor rotor of magnet can directly installation in locomotive round on of hinge Shang, to saves has deceleration gear box, structure was simplified; and as PM wind generator, motor made outside rotor straight drive structure, motor of rotor and impeller made a overall, with impeller with turned, Stator fixed to the supporting tower.

B, because of the permanent-magnet synchronous motor speed control parameters without the limitation of motor pole number, easy to direct-drive motor loads, eliminating the noise and gearbox with high failure rates, increased flexibility in the design of mechanical transmission system.

4, high reliability:

From motor ontology to compared, PM synchronization frequency adjustable speed motor and asynchronous motor of reliability quite, but due to PM synchronization motor structure of flexibility, easy achieved directly drive load, saves reliability not high of deceleration box; in some load conditions Xia even can will motor design in its drive device of internal, as wind power straight drive device, oil rig of winch drive device, to can saves traditional motor fault rate high of bearing: greatly improve has drive system of reliability.

5, small size, power density:

Permanent-magnet synchronous motor speed control of small size, high power density advantage focuses on driving at low speed, high torque load, one is the increase in the number of poles of the motor, motor volume can be reduced. There is that motor efficiency increased, with a corresponding loss reduction, motor temperature decreases, the cases with the same insulation class motor size can be designed smaller motor structure flexibility can save many invalid parts of the motor, such as end-winding rotor end-ring, the appropriate size can be smaller

6, high starting torque, low noise, low temperature rise:

A, permanent magnet synchronous motor in low frequency can keep up the good work, the output torque at low frequency induction motor, noise at run time;

B no ohmic losses and rotor, stator winding little reactive current and low temperature rise, power of permanent magnet motor of the same size and weight can be increased by 30% about permanent magnet motor with power capacity volume, weight, material can be used by 30%.