Causes and solutions for overcurrent in high-frequency induction heating equipment

The following are some reasons and corresponding solutions for over-current in high-frequency induction heating equipment

Causes:

（1） Internal component failure of equipment

Power device damage：

Power devices such as IGBT and thyristor may experience performance degradation or damage after long-term use or exposure to over-voltage and over-current shocks, leading to uncontrolled current flow

Capacitor malfunction：

Aging, leakage, and breakdown of capacitors can cause changes in circuit parameters and lead to overcurrent

（2） Induction coil issue

Induction coil short circuit：

The insulation layer of the coil is damaged, and there is a short circuit between adjacent turns, which reduces the equivalent impedance of the coil and increases the current

Short circuit between coil and work-piece contact：

During the heating process, the coil comes into contact with the heated work-piece, causing a short circuit

（3） Load matching issue

Overload

Too many work-pieces are heated simultaneously, exceeding the rated load of the equipment, resulting in excessive current

Changes in load characteristics：

The material composition, size, shape, etc. of the heated work-piece change, resulting in a change in the impedance characteristics of the load and an abnormal increase in the output current of the equipment

（4） Control system malfunction

Current detection circuit malfunction：

The sensor used to detect current is damaged and the signal transmission line is faulty, resulting in inaccurate current feedback signals received by the control system and inability to adjust the output correctly

Control program exception：

The control program of the device has an error, causing unreasonable parameters such as output power or frequency, resulting in over-current

（5） External interference

Power grid fluctuations：

Sudden increase or decrease in grid voltage can cause abnormal input power supply to equipment, which may lead to over-current

electromagnetic interference：

There is a strong electromagnetic field interference source near the equipment, which affects the normal operation of the equipment and generates over-current phenomenon

Solution:

（1） Check and replace damaged components

Use professional instruments to test power devices and capacitors, and replace damaged components

Regularly maintain and upkeep equipment, promptly identify and address issues such as component aging

（2） Repair the induction coil

Check the insulation condition of the induction coil and repair the damaged parts with insulation or rewire the coil

Adjust the relative position between the coil and the work-piece to ensure that there is no contact between the coil and the work-piece during the heating process

（3） Reasonably adjust the load

Reasonably arrange the number of work-pieces and heating process according to the rated load of the equipment

Adjust the operating parameters of the equipment to match the new load conditions in response to changes in load characteristics

（4） Repair the control system

Check the current detection circuit, repair or replace damaged sensors and circuits