SCR thyristor medium frequency induction heating equipment

The medium frequency induction heating equipment adopts the structure of AC direct AC frequency conversion power supply with Thyristor Medium frequency induction heating power. The water cooled high voltage high power fast thyristor bridge group constitutes a resonant inverter. The inverter locking circuit adopts all digital control technology, high standard electromagnetic compatibility design, compact and modular design facilitates user dimension. Protection and maintenance.

Application scope
Metal smelting, brazing, welding, forging, heating, coating, hot assembly, tempering, quenching, annealing, normalizing, etc.

Technological index

Power scope: 500kW-10000kW

Frequency scope: 20Hz-3000Hz

Rated DC voltage: 500V-1500V

Power grid voltage: 220V~660V,50/60Hz,3-phase


Function & structure

SCR medium induction heating power supply adopts AC-DC-AC variable frequency structure. Small and medium power supply rectifier adopt 3-phase thyristor rectifying. 12-pulse thyristor rectifying is adopted for large power equipment to improve power level and reduce grid side harmonic current. The inverter adopts high voltage large power fast thyristor module to form inverter power unit, and realize large power output by superimposition of inverter power unit.

There're two types structure for inverter and resonance tank circuit: 1) parallel resonance, 2) series resonance.

Parallel resonance type: adopt high voltage large power water cooling SCR to form current type inverter power unit. Realize large power output by power superimposition of inverter power unit. Generally resonant tank circuit adopts pure parallel resonant structure, or choose voltage-multiplying or transformer mode for different load situations.

Parallel resonance type: adopt high voltage large power water cooling SCR and fast recovery diode to form voltage type inverter power unit. Realize large power output by superimposition of inverter power unit. Resonant tank circuit adopts series resonant structure, or choose transformer matching mode for different load situations.

Series type SCR medium frequency equipment has the advantages of high grid side power factor, wide scope of power regulation, high heating efficiency and high startup success rate with wide application.

The complete set of equipment is composed of SCR medium frequency power supply cabinet, resonance tank circuit cabinet, circulation soft water cooler, control desk (optional), automatic control system (optional), etc.




parallel SCR medium power supply        series SCR medium frequency power supply  (half bridge structure)


Technical features

1) Adopt water cooling large power fast thyristor bridge to form resonant inverter. Parallel resonance structure can be used for heat treatment field; series resonance structure can be used for smelting field.

2) The inverter phase-lock circuit adopt full digital control technology. Main control chip uses industrial CPLD with high reliability and flexibility. Not only does it have high phase locking precision, but also it can meet the special requirement to peripheral interface for different users.

3) The rectifier adopts advanced FPGA micro processing control system, to realize precise synchronous triggering, high precision control and small grid-side non-characteristic harmonic. It can realize different operation mode of constant power, constant voltage and constant current.

4) For series resonant power supply, inverter side adopts " frequency modulation and limit angle" control technology, which can ensure the highest DC rated voltage during full power regulation scope, having perfect load adaptability, high electrical efficiency and high grid side power factor.

5) High standard electromagnetic compatibility design and compact and modular design is convenient for the customer's mainteance and repair.

6) It has the perfect protection function of over voltage, over current, Loss of lock, temperature and water flow, with reliable operation and low failure rate.

7) Adopt PLC and colorful touch screen to form the perfect friendly human-machine interface. Not only does It realize the communication control with user host computer by Ethernet or DP communication mode, but also it can achieve automatic logic control, fault display and fault diagnosis function of power supply system.