What is the difference between inverter energy consumption braking and motor energy consumption braking?
Energy consumption braking is to rely solely on the motor to consume kinetic energy to achieve the purpose of parking. Therefore, the braking effect and accuracy are not ideal. In some occasions requiring short braking time and good braking effect, this brake is not normally used. Such as lifting machinery, its operation is characterized by low motor speed, frequent start, stop and reverse, and drag the weight of the operation. In order to achieve accurate and flexible control, the motor is often in a state of braking, and requires large braking torque. The energy consumption brake can not meet the above requirements. Therefore, lifting machinery generally adopts reverse braking, and requires mechanical braking, in case the weight is slipped during running or losing power.
When the motor is disconnected from the power supply, in order to make the motor stop quickly, using the power control method in motor power supply coupled with the normal operation of power supply phase at this time, the direction of rotation of the rotation direction of the motor rotor and the motor rotating magnetic field in electromagnetic force at the moment is generated by the motor brake torque, motor speed reducer. Using the Q switch voltage at both ends of the armature is disconnected from the power grid, and it will immediately receive a braking resistor RL, at this time, the main magnetic field in the motor armature remains unchanged, the cause inertia continues to rotate the torque braking torque, the motor speed down, until the stop.
Your question, I think it is the difference between regenerative braking and braking of the motor function for active inverter regenerative braking to use inverter feedback power, so there is the braking inverter of the argument?? First of all, define some of your concepts, the motor is divided into reverse braking, energy consumption braking, regenerative braking three. The energy consumption braking of the inverter is called the energy consumption braking by using the braking resistance in the DC loop to absorb the regenerative electric energy of the motor,The utility model has the advantages of simple structure; no pollution to the power grid (for comparison, action and feedback) low cost; the disadvantage is low efficiency, especially to consume a lot of energy and braking resistance will be in frequent braking capacity will increase.
A direct current is generated in the stator winding so that a fixed magnetic field is generated. At this point, the rotor cuts the magnetic field lines in the direction of rotation, resulting in a braking torque. Because the braking method is not like regenerative braking (using frequency converter), the energy generated by braking is fed back to the grid, but the energy is dissipated by the motor alone, so it is called energy consumption braking. The utility model is also used for braking by direct current in the stator winding, so the energy consumption braking is called DC injection braking. By using the backward switch Q to return the point voltage back to the grid, the armature current will become a copy, and the current will be of the same magnitude, resulting in a great braking torque of the motor, which will stop the motor.
The reverse brake has one of the biggest disadvantages: when the motor speed is 0, if the power supply is not removed in time, the motor will reverse. There are two methods to solve this problem: 1, in the control loop of the motor power supply phase, adding a time relay, when the brake after a period of time, disconnect the power after inversion, so as to avoid motor reversal. But the braking time is difficult to estimate because of this method, so the braking effect is not accurate. 2. A speed relay is added to the control circuit of the motor's inverting power supply. When the sensor detects the speed of the motor is 0, the inverter power of the motor is cut off in time. Because of this method, the speed relay monitors the motor speed in real time, so the braking effect is much better than the last one. It is precisely because reverse braking has this characteristic, therefore, it is not allowed to reverse the machinery, such as some lathes, etc., the brake method can not use reverse braking, and can only use energy consumption braking or mechanical brake.
