Servo electromagnetic brake solution


1. Solution

As a safety component in mechanical equipments, with the gradual replacement of hydraulic and pneumatic braking in applications, the market requires a break which has a better braking performance. The response time, braking torque and thermal decay of electromagnetic brake are the key factors to determine the braking performance. If the braking time is too long, the load’s gravity potential energy will transformed into a longer the sliding distance, which will aggravate the wear of the brake rotor and seriously shorten the service life of the brake. Similarly, if the electromagnetic brake can’t withstand a high temperature, the coil of the brake will be easily burned up under the back EMF during power failure. For the braking torque of the brake, users usually expect a larger number, which means that the coil current generating electromagnetic force should increase, and then the braking power will increase.

2. Specific implementation plan

When facing power failure, the response time to apply break is a key technical index of electromagnetic brake. The power loss form of electromagnetic brake is closely related to the braking characteristic of the brake, which has an important impact on the dynamic voltage, current, electromagnetic force, braking torque and braking effect in the braking process.


Firstly, based on the finite element simulation software, we can optimized the magnetic circuit structure of the brake, we can also regulate the ratio of electromagnetic force to spring force to ensure that the brake can be released in time when power is on and applied quickly when power is off. Secondly, using PWM technology, we can give it larger excitation voltage when the brake is released, and a small holding voltage when holding to reduce the initial current in the coil when power is off. In addition, the coil end is connected in reverse parallel to the discharge circuit to reduce the reverse voltage and to realize the rapid release of coil energy. Meanwhile, based on the multi physical field coupling simulation, considering the hysteresis effect of soft magnetic materials, combined with the control strategy, we can accurately calculate the dynamic, steady-state of the electromagnetic break and its mechanical characteristic.