CN203851038U - Boost circuit for medium frequency furnace - Google Patents

Abstract

The utility model discloses a boost circuit for a medium frequency furnace, and the boost circuit comprises an electric furnace RL and a compensation capacitor group C1 which is in parallel connection with the electric furnace RL. The compensation capacitor group C1 is connected in parallel between an inverter bridge and the electric furnace RL. The electric furnace RL is in series connection with a boost capacitor group C2 which is connected at a high-voltage side of the electric furnace RL in a series connection manner. The capacity of the boost capacitor group C2 is the half of the capacity of the compensation capacitor group C1. Compared with the prior art, the boost circuit provided by the utility model is provided with the boost capacitor group C2 which is connected at the high-voltage side of the electric furnace RL in a series connection manner. When the powers of electric furnaces are the same, a voltage across two ends of the electric furnace RL is higher, a current passing through the electric furnace RL is lower, and the electric energy loss of the electric furnace RL is lower, thereby effectively improving the power factor of the electric furnaces, and greatly improving the utilization rate of the electric energy.

Description

A kind of booster circuit of middle frequency furnace

Technical field

The utility model relates to a kind of booster circuit of middle frequency furnace of field of metallurgy, especially relates to a kind of booster circuit of controllable silicon middle frequency furnace.

Background technology

Middle frequency furnace is that a kind of supply unit that changes power frequency 50HZ alternating current into intermediate frequency (300HZ is above to 10000HZ) is three-phase main-frequency alternating current, after rectification, become direct current, again direct current is become to adjustable electric current of intermediate frequency, supply is by the intermediate frequency alternating current flowing through in electric capacity and induction coil, in induction coil, produce the highdensity magnetic line of force, and cut the metal material holding in induction coil, in metal material, produce very large eddy current.This eddy current has the properties of electric current of intermediate frequency equally, that is, the free electron of metal self will produce heat having in the metallic object of resistance to flow.For example, a metal cylinder is placed in the induction coil of alternation electric current of intermediate frequency, metal cylinder does not directly contact with induction coil, hot-wire coil self-temperature is very low, periphery is heated to rubescent, even fusing, and the power that this speed rubescent and fusing needs only regulating frequency size and electric current just can realize.If cylinder is placed on hub of a spool, the temperature of cylinder periphery is the same so, and cylinder heating and melting does not produce pernicious gas, optic pollution environment yet.It is comprised of several parts such as converter plant, body of heater, stokehold controls.

An important component part of thyristor intermediate frequency electric source middle frequency furnace, that three-phase main-frequency alternating current is become to direct current through rectification circuit, through inverter circuit, be output as single-phase medium frequency alternating current again and supply with medium frequency response ratio, then utilize electromagnetic induction principle, put workpiece and in alternating magnetic field, produce eddy current and generate heat, reach melting, quenching, the heat request that adds such as diathermanous.But current thyristor intermediate frequency electric source circuit is generally shown in Fig. 2, comprises electric furnace R _lwith building-out capacitor group C1, electric furnace R _lc1 connects with building-out capacitor group, as building-out capacitor group C1 both end voltage U _dduring=750V, electric furnace R _lthe voltage U at two ends _l=750V, in theory, the power factor of electric furnace only has 0.2～0.3 left and right, and utilization rate of electrical is low.

Summary of the invention

The utility model, for the low deficiency of thyristor intermediate frequency electric source circuit utilization rate of electrical of middle frequency furnace of the prior art, provides a kind of and can effectively improve middle frequency furnace power factor, improves the booster circuit of utilization rate of electrical.

For solving the problems of the technologies described above, the utility model is solved by following technical proposals:

A booster circuit for middle frequency furnace, comprises an electric furnace R _lwith one group of building-out capacitor group C1 in parallel with electric furnace, building-out capacitor group C1 is connected in parallel on inverter bridge and electric furnace R _lbetween, it is characterized in that described electric furnace R _lon branch road, be in series with a boost capacitor group C2.

In technique scheme, described boost capacitor group C2 is connected on electric furnace R _lhigh-pressure side.

In technique scheme, the capacity of described boost capacitor group C2 is 1/2 of described building-out capacitor group C1 capacity.

By technique scheme, obtain following beneficial effect:

1, compared with prior art, the booster circuit of the middle frequency furnace that the utility model provides, at the furnace high-voltage side boost capacitor group C2 that connects, when furnace power is identical, electric furnace R _lthe voltage U at two ends _lhigher, by electric furnace R _lelectric current less, electric furnace R _lelectric energy loss less, effectively improve the power factor of electric furnace, thereby greatly improve utilization rate of electrical.

2, in the situation that furnace power is identical, when the capacity of boost capacitor group C2 be building-out capacitor group C1 capacity 1/2 time, electric furnace R _lthe voltage U at two ends _lthe highest, i.e. electric furnace R _lloss power less, further improve utilization rate of electrical.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of middle frequency furnace.

Fig. 2 is the circuit diagram of the booster circuit of middle frequency furnace in prior art.

Fig. 3 is the booster circuit figure shown in Fig. 1.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the utility model is described in further detail.

Referring to Fig. 1, the circuit diagram of middle frequency furnace, three-phase alternating-current supply, through rectifier bridge and inverter bridge, forms Unidirectional direct-current power supply, building-out capacitor group C1 and electric furnace R _lparallel connection, electric furnace R _lthe high-pressure side of branch road is in series with boost capacitor group C2.

In conjunction with Fig. 1 and Fig. 3, in actual use, the voltage U at building-out capacitor group C1 two ends _dbe generally 750V, when the capacity of boost capacitor group C2 equals the capacity of building-out capacitor group C1, electric furnace R _lthe voltage U at two ends _l=(1+C1/C2) U _d=2U _d, i.e. U _l=1500V, at electric furnace R _lunder equal-wattage, electric furnace R _lthe voltage U at two ends _dbe doubled, due to the P of electric furnace _lossvoltage U with electric furnace two ends _lbe inverse relation, electric furnace R _lelectric energy loss reduced one times.

According to U _l=(1+C1/C2) U _d, known, the capacity ratio of the capacity of boost capacitor group C2 and building-out capacitor group C1 is less, electric furnace R _lloss power less.

As preferably, in the booster circuit of the middle frequency furnace that the utility model provides, the capacity of boost capacitor group C2 is 1/2 of building-out capacitor group C1 capacity.When the voltage U d=750V at building-out capacitor group C1 two ends, boost capacitor group C2=1/2C1, electric furnace R _lthe voltage U at two ends _l=(1+C1/C2) U _d=3U _d, i.e. U _l=2250V, at electric furnace R _lunder equal-wattage, electric furnace R _lthe voltage U at two ends _d2 times have been improved.

Compared with prior art, the booster circuit of the middle frequency furnace that the utility model provides, at the furnace high-voltage side boost capacitor group C2 that connects, when furnace power is identical, electric furnace R _lthe voltage U at two ends _lhigher, by electric furnace R _lelectric current less, electric furnace R _lelectric energy loss less, effectively improve the power factor of electric furnace, thereby greatly improve utilization rate of electrical.

Claims (3)

1. a booster circuit for middle frequency furnace, comprises an electric furnace R _lwith one group of building-out capacitor group C1 in parallel with electric furnace, building-out capacitor group C1 is connected in parallel on inverter bridge and electric furnace R _lbetween, it is characterized in that described electric furnace R _lon branch road, be in series with a boost capacitor group C2.

2. the booster circuit of a kind of middle frequency furnace according to claim 1, is characterized in that, described boost capacitor group C2 is connected on electric furnace R _lhigh-pressure side.

3. the booster circuit of a kind of middle frequency furnace according to claim 2, is characterized in that, the capacity of described boost capacitor group C2 is 1/2 of described building-out capacitor group C1 capacity.