What is the over-current of the inverter?
The reason of the frequency converter itself:?1, parameter setting problem: for example, the acceleration time is too short, the PID regulator's proportion P, the integral time I parameter is unreasonable, the overshoot is too big, causes the frequency changer output current oscillation.?2 、 frequency converter hardware problem:
External cause:?1, the motor load mutation caused by excessive impact, resulting in excessive flow.?2, the motor and motor cable phase or insulation damage to each other, resulting in short circuit turns to the ground, resulting in over-current.?3, over-current fault and motor leakage reactance, motor cable coupling reactance, so choose motor cable must be selected according to requirements.?4. Power factor correction capacitor or surge absorption device on the output side of inverter.?5. When the speed feedback signal is lost or abnormal, it will cause excessive flow, and check the encoder and its cable.
When the load is not stable, recommend the use of DTC DTC control mode, because the speed is very fast, the actual torque and flux generated every 25 microseconds a set of precise value after comparator and output torque of the motor flux comparator, optimized pulse selector switch inverter decided to best position, such a system over current. In addition, the speed loop adaptive (AUTOTUNE) will automatically adjust the PID parameters, so that the inverter output motor current is stable.
Inverter hardware problems:?(1) the current transformer is damaged. The phenomenon is that the main circuit of the converter sends power. When the converter is not started, the current is displayed and the current is changing, so that the transformer is damaged.?(2) the main circuit interface board, the current and voltage detection channels are damaged, and there will be over-current. The damage to the circuit board may be:?Because of the poor environment, conductive solid particles are attached to the circuit board to cause electrostatic damage. Or corrosive gases that cause the circuit to corrode.?Zero potential circuit board and the casing are connected together, the cabinet and the angle of welding, a powerful arc, will affect the performance of circuit board.?Due to poor grounding, the circuit board zero volts interference, it will cause damage to the circuit board.?(3) because the connection plug is not tight and unstable. For example, the current or voltage feedback signal line is not in good contact, and sometimes the over-current fault occurs.
