Basic functions of inverter

- Oct 10, 2019-

In addition to the basic functions of motor frequency conversion speed regulation, the frequency converter also has frequency control, automatic acceleration and deceleration, multi-speed operation, various parking modes, various control modes, braking, protection and communication functions.

  1. Frequency control function

    The operating frequency of the inverter can be controlled by the function keys on the operation panel, or by the function parameters of digital presets, or by the external analog terminals, or by the communication data of the upper computer.

  2. Automatic acceleration and deceleration function

    The inverter can realize the optimal acceleration and deceleration control, and automatically set the minimum acceleration and deceleration time according to the load state of the motor, or control the acceleration and deceleration current within the maximum acceleration and deceleration time.

    There are three modes of acceleration and deceleration of frequency converter, linear mode, s-shaped mode and half-s-shaped mode, as shown in the following figure.Linear mode: in the acceleration process, the output frequency of the inverter increases linearly in the acceleration time.As shown in figure (a).S-shaped: the acceleration coroutine is relatively slow at the beginning and end stage, and is accelerated in a linear way at the middle stage. The acceleration process is s-shaped, as shown in figure (b).Semi-s-shaped mode: the acceleration coprocess is relatively slow at the beginning stage, and is accelerated in a linear way at the middle stage, and the acceleration process is semi-s-shaped, as shown in figure (c).

    Acceleration and deceleration of frequency converter

  3. Multi-stage speed operation

    The inverter can perform multi-stage speed operation according to the preset speed value and running time. A complete working process can be divided into several program steps. The rotation direction, running speed, working time or distance of each program step can be preset.

  4. Various parking methods

    The parking mode of frequency converter can choose decelerate stop, free stop, decelerate stop + dc brake to reduce the impact on mechanical parts and motors, thus making the speed regulating system more reliable.

  5. Control function

    The inverter has the functions of torque promotion, torque compensation, torque limitation, capture and restart, vector control, PID control and so on.

  6. Braking function

    Inverter has energy consumption brake and dc brake two ways.Energy consumption braking is a magnetic flux braking method. Motor deceleration and stopping can be realized by reducing the output frequency of the frequency converter.

    When the frequency converter reduces the frequency, the synchronous speed of the motor decreases.When the synchronous speed n0 is less than the rotor speed of the motor, the phase of the motor's current changes 180 degrees, and the torque on the motor shaft becomes the braking torque, so as to realize braking. The energy on the motor is consumed through the braking resistance.

    Dc braking is when the motor's speed drops to a preset braking speed, the inverter injects a dc voltage into the motor to stop it and locks the rotor at zero speed.

  7. Protection function

    The inverter has the fault protection for itself and the motor.The fault protection function of inverter itself includes overload protection, over-current protection, regenerative over-voltage protection, abnormal cooling fan, etc.The fault protection functions of the motor include grounding protection, overload protection, over-current protection, over-voltage protection, under-voltage protection, phase-out protection, over-frequency protection, stall protection, etc.

  8. Communication function

    The inverter has rs232/485 communication interface, which can realize the communication function of the upper industrial computer to the inverter, accept the operation instruction of the upper computer or upload the operation status of the inverter.The perfect software function and the standard communication protocol can realize the flexible system configuration and constitute the field bus system.