What kind of braking method is the DC braking of the inverter?

DC braking voltage value, the essence is to set the size of the braking torque, obviously the greater the inertia of the drag system, the DC braking voltage value should be correspondingly larger, the general DC voltage is about 15-20% of the rated output voltage of the inverter is about 60-80V, and some use the percentage of braking current;

DC braking time, i.e. the time it takes to introduce DC current to the stator windings, should be slightly longer than the actual required downtime;

DC braking starting frequency, when the working frequency of the inverter drops to how big it begins, it starts to change from energy consumption braking to DC braking, which is related to the load requirements for braking time, if there is no strict requirement, DC braking starting frequency is set as small as possible.

Inverter DC braking.

Generally, when the output frequency of the inverter is close to zero and the motor speed is reduced to a certain value, the inverter redirects to the direct current in the winding of the asynchronous motor to form a static magnetic field. DC braking can be used in situations where accurate control of the motor is required or for irregular rotation of the brake motor due to external factors before starting.

Elements of DC braking.

1. DC braking voltage value, the essence is to set the size of braking torque, obviously the greater the inertia of the drag system, the DC braking voltage value should be correspondingly larger, the rated output voltage of the inverter with a general DC voltage of about 15-20% is about 60-80V, and some use the percentage of braking current;

2. DC braking time, that is, the time when DC current is introduced to the stator winding, it should be slightly longer than the actual required shutdown time;

3. DC braking starting frequency, when the working frequency of the inverter drops to how big it becomes, it starts to change from energy consumption braking to DC braking, which is related to the load requirements for braking time, if there is no strict requirement, the DC braking starting frequency is set as small as possible;

It is to add DC to the motor to the inverter, generate a fixed magnetic field, and the motor cuts the magnetic field to generate electricity, and consumes the kinetic energy on the rotor in the form of thermal energy, so that the motor stops running quickly

Set the parameters of the DC braking of the inverter, one is the DC braking frequency, and the other is the DC braking voltage.

When the machine stops, after the output frequency drops to the set frequency, the inverter will output a DC voltage, which is determined by the parameters just now, generally as a percentage.

When the direct current is introduced into the stator winding of the asynchronous motor, the magnetic field generated will be a constant magnetic field with constant spatial position, and the rotor continues to rotate at its original speed due to inertia, at this time, the rotating rotor cuts this static magnetic field and produces braking torque, and the kinetic energy stored by the system is converted into electrical energy and consumed in the rotor circuit of the motor, so as to achieve the effect of rapid braking of the motor.

In order to ensure the safety of the electric motor, DC braking is best used in conjunction with energy consumption braking.

There are three types of electric braking for <> DC motors: reverse braking, energy consumption braking, and regenerative braking.

1. Reverse braking: after the motor disconnects the power supply, in order to make the motor stop quickly, the power supply that is inverted with the normal operation power supply is added to the power supply of the motor by using the control method, at this time, the rotation direction of the motor rotor is opposite to the rotation direction of the rotating magnetic field of the motor, and the electromagnetic torque generated by the motor is the braking torque to accelerate the deceleration of the motor.

2. Energy consumption braking: direct current is passed through the stator winding, so as to generate a fixed magnetic field. At this point, the rotor cuts the magnetic field lines in the direction of rotation, creating a braking torque.

The energy generated during braking is fed back to the power grid, but the kinetic energy is consumed by the motor alone, so it is called energy consumption braking. 3. Regenerative braking: When the rotor speed of the motor exceeds the rotation speed of the synchronous magnetic field of the motor, the rotation direction of the electromagnetic torque generated by the rotor winding is opposite to the rotation direction of the rotor, and the motor is in the braking state.

1. Reverse braking (not commonly used).

2. Regenerative braking (feedback braking) charges the battery or consumes it with resistance.

3. Electromagnetic braking.

When the DC power supply is supplied to the armature winding through the brush, the conductor under the n pole on the surface of the armature can flow through the current in the same direction, and the conductor will be subjected to the torque in the counterclockwise direction according to the left-hand rule; The conductor under the S pole on the surface of the armature also flows through the current in the same direction, and the conductor will also be subjected to a moment in the counterclockwise direction according to the left-handed rule.

1. Mechanical braking is a brake, which is an electric brake, also known as a brake.

2. Energy consumption braking. It refers to the DC motor in operation suddenly disconnects the armature power supply, and then inserts a braking resistor in the armature circuit, so that the inertia energy of the armature winding is consumed on the resistor, so that the motor brakes quickly. Since the voltage and input power are both 0, the braking is balanced and the circuit is simple;

3. Reverse braking. In order to achieve a quick shutdown, the armature voltage of the motor in operation is suddenly reversed, and a resistor is inserted in the armature circuit, which is called reverse braking of the power supply. During braking, the power supply is still input power, and the kinetic energy and electromagnetic power released by the load are consumed on the resistor, which is suitable for the occasion of rapid stop and reversal, and has a large impact on the equipment.

Reverse braking: when the forward power supply is cut off, the reverse power supply is added immediately to make the motor stop quickly, and when the motor speed drops to zero, the "reverse relay" installed on the motor shaft immediately sends out a signal to cut off the reverse power supply to prevent the motor from really reversing.

4. Reverse pull reversal braking is suitable for low-speed lowering heavy objects. When braking, a large resistor is inserted into the circuit, and the armature current becomes smaller and the electromagnetic torque becomes smaller. Due to the large size of the series resistance, different drop speeds can be obtained by changing the size of the series resistance value.

5. Feedback braking. The motor running in the electric state will be dragged by the load under certain conditions, and the N>N0, EA>U, and IA will be reversed, and the motor will change from driving to braking.

1. Reverse braking (not commonly used).

2. Regenerative braking (feedback braking) charges the battery or consumes it with resistance.

3. Electromagnetic braking.

When the DC power supply is supplied to the armature winding through the brush, the conductor under the n pole on the surface of the armature can flow through the current in the same direction, and the conductor will be subjected to the torque in the counterclockwise direction according to the left-hand rule; The conductor under the S pole on the surface of the armature also flows through the current in the same direction, and the conductor will also be subjected to a moment in the counterclockwise direction according to the left-handed rule.

1. Reverse braking 2, energy consumption braking 3, electromagnetic braking.

The braking method has the following cases:

Power braking. Regenerative braking.

Multi-inverter drive with common DC bus.

DC braking. The multi-inverter transmission of the shared DC bus can be divided into two ways: the shared DC balanced bus and the shared DC loop bus. The common DC equalization bus method is to use the connection module to connect to the DC loop bus.

The connection module includes a reactor, a fuse and a contactor, which must be individually designed on a case-by-case basis. Each inverter is relatively independent and can be connected to or off the DC bus as needed.

Variable-frequency drive (VFD) is a power control device that uses frequency conversion technology and microelectronics technology to control AC motors by changing the frequency of the motor's working power supply.

The inverter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit, microprocessor unit, etc.

The inverter relies on the interruption of the internal IGBT to adjust the voltage and frequency of the output power supply, and provides the required power supply voltage according to the actual needs of the motor, so as to achieve the purpose of energy saving and speed regulation. With the continuous improvement of industrial automation, frequency converters have also been widely used.

Hello, I am glad to serve you and give you the following answer: it cannot be used at the same time, because the resistance braking and DC braking of the inverter have different working principles, and the working methods between them are very different. 1. Inverter resistance brakingInverter resistance braking is a method of reducing the speed of the generator with resistance, which connects the resistor to the output end of the inverter to offset the current output of the inverter and reduce the speed of the generator.

Resistance braking can achieve fast braking, but due to the long braking time of resistance braking, it can cause damage to the inverter. 2. Inverter DC brakingInverter DC braking is a method of connecting the DC power supply to the output end of the inverter to offset the current output of the inverter, thereby reducing the speed of the generator. DC braking can achieve fast braking without causing damage to the inverter.

Solutions and practices: 1. According to the actual situation, resistance braking or DC braking can be selected in operation to achieve the best braking effect. 2. When installing the inverter, the circuit of resistance braking and DC braking should be correctly installed according to the installation instructions of the inverter to ensure the normal operation of the inverter.

3. During operation, the resistance braking and DC braking circuits of the inverter should be checked regularly, and if there is any problem, it should be repaired or replaced in time.