CN219576880U - Carbon electric forging furnace system with novel power supply mode - Google Patents

Abstract

The utility model relates to a carbon electric forging furnace system with a novel power supply mode, wherein the input end of a primary winding of a transformer is respectively connected with the output end of a bidirectional thyristor, the input end of the bidirectional thyristor is connected with a three-phase power supply, the output end of a secondary winding of the transformer is respectively connected with the positive electrode of a diode, the negative electrode of the diode is connected with a direct current bus, and the direct current bus is connected with the carbon electric forging furnace. The original rectifying circuit power supply mode of the Y/[ delta ] connection method with the balance reactor is improved into a three-phase five-column double-inverse-star six-pulse rectifying power supply mode, the primary side is subjected to voltage regulation, and the secondary side is subjected to rectification, so that the balance reactor in the traditional alternating current voltage regulation circuit is omitted, the circuit structure is simplified, the volume of rectifying equipment is reduced, the direct current component is increased, the power factor is increased by more than 90%, the operation loss is smaller, the short-net power supply is realized for the carbon electric forging furnace, meanwhile, the operation quality of a power grid is greatly improved, the power utilization efficiency is improved, the advantages of green energy conservation are reflected, and the energy-saving effect is obvious.

Description

Carbon electric forging furnace system with novel power supply mode

Technical Field

The utility model relates to the technical field of power supply modes of carbon electric forging furnaces, in particular to a carbon electric forging furnace system with a novel power supply mode.

Background

The high-power rectifying device is widely applied to various fields such as aluminum electrolysis, graphite carbon smelting and the like, the rectifying transformer is one of the most important devices in the high-power rectifying device, and along with the continuous development of society, the individuation demands are also increased, wherein the rectifying transformer for the graphite carbon smelting is one of the devices. At present, the carbon electro-forging furnaces in China all adopt a direct current power supply mode, an adjustable direct current power supply with low voltage and large current is frequently used in harmonic interference source load equipment such as a large number of thyristors for rectification and conversion, a carbon electro-forging furnace, an intermediate frequency furnace, a single crystal furnace and the like, for example, an adjustable direct current power supply with thousands of amperes on tens of volts is often used in the traditional mode, and a rectifying circuit (see figure 1) with a balancing reactor is mostly adopted in the traditional mode.

Disclosure of Invention

Based on the above, it is necessary to solve the problems that in the prior art, the rectifying circuit with the balance reactor is used for supplying power to the carbon electro-forging furnace by adopting a Y/[ delta ] connection method, the energy-saving effect is poor, and pollution is caused to the carbon electro-forging furnace and a peripheral power grid. The utility model provides a carbon electric forging furnace system with novel power supply mode, the rectification circuit power supply mode of taking balance reactor with original Y/[ delta ] connection method, change into three-phase five post double anti-star six pulse wave rectification power supply mode, the former side carries out the pressure regulating, vice side rectification, the balance reactor in the traditional AC voltage regulating circuit has been omitted, the circuit structure has been simplified, the rectifier unit volume has been reduced, direct current component has been increased, power factor has been improved more than 90%, the running loss is less, realize the short net power supply to carbon electric forging furnace, simultaneously also improved electric wire netting operation quality greatly, power consumption efficiency has been improved, green energy-conserving advantage has been embodied, the energy-conserving effect is obvious.

The utility model provides a carbon element electric forging furnace system with novel power supply mode, includes carbon element electric forging furnace, transformer primary winding, transformer secondary winding, two-way silicon controlled rectifier and diode, the input of transformer primary winding respectively with the output of two-way silicon controlled rectifier links to each other, the input of two-way silicon controlled rectifier links to each other with three-phase power, the output of transformer secondary winding respectively with the positive pole of diode links to each other, the negative pole of diode is connected with the direct current busbar, the direct current busbar with carbon element electric forging furnace is connected.

Preferably, in the carbon electric forging furnace system with the novel power supply mode, the bidirectional thyristor comprises a ring circuit and two unidirectional thyristors arranged on the ring circuit, an input end and an output end of the bidirectional thyristor are arranged between the two unidirectional thyristors,

and in the direction that the input end of the bidirectional thyristor points to the output end of the bidirectional thyristor, the conducting directions of the two unidirectional thyristors are opposite.

Preferably, in the carbon electric forging furnace system with the novel power supply mode, the unidirectional thyristor is a cathode controlled unidirectional thyristor.

Preferably, in the carbon electric forging furnace system with the novel power supply mode, the bidirectional thyristor is a bidirectional thyristor.

Preferably, in the carbon electric forging furnace system with the novel power supply mode, the secondary winding structure of the transformer is as follows: u and u 'are wound on a phase iron core, v and v' are wound on a phase iron core, w and w 'are wound on a phase iron core, and two groups of three-phase half-wave rectification circuits are formed, wherein u, v and w are positive groups u', v 'and w' are reverse groups.

The technical scheme adopted by the utility model can achieve the following beneficial effects:

in the carbon electric forging furnace system with the novel power supply mode, the technical improvement is made on a rectifying circuit in the carbon electric forging furnace system, the original Y/[ delta ] connection method is improved to a three-phase five-column double-inverse-star six-pulse wave rectifying power supply mode, the primary side is subjected to voltage regulation, the secondary side is rectified, namely, a bidirectional thyristor is additionally arranged on the primary side of a transformer, the secondary side adopts two groups of three-phase half-wave rectifying circuits to output six-pulse wave direct current power supplies in parallel, the balancing reactor in the traditional alternating current voltage regulating circuit is omitted, the circuit structure is simplified, the volume of rectifying equipment is reduced, the direct current component is increased, the power factor is increased by more than 90%, the operation loss is small, the short-network power supply is realized for the carbon electric forging furnace, the operation quality of a power grid is greatly improved, the power utilization efficiency is improved, the advantages of green and energy conservation are reflected, and the energy conservation effect is obvious. Through theoretical operation and actual operation verification, the utility model regulates voltage at the primary side, while the traditional power supply regulates voltage at the secondary side of the transformer, and under the condition of the same load, the current of the former is small, and the loss of the transformer is small; the utility model adopts a double-inverse star connection method, and the transformer of the traditional power supply adopts a Y/delta connection method, and the leakage reactance of the former transformer does not influence the commercial power, so the harmonic wave is small, and the power factor is high; in each cycle (20 ms), the average on time of each diode 400 in the utility model is 6.7ms, and the on time of each thyristor in the traditional power supply is also 6.7ms, but the current value of the former is twice smaller than that of the latter, so the heat loss is small, and the heat dissipation is facilitated.

Drawings

FIG. 1 is a schematic diagram of a rectifying circuit with a balancing reactor in the prior art with Y/DELTAconnection;

FIG. 2 is a schematic diagram of a carbon electric forging furnace system with a novel power supply mode according to an embodiment of the utility model.

Wherein: the transformer primary winding 100, the transformer secondary winding 200, the bidirectional thyristor 300, the diode 400 and the direct current bus 500.

Detailed Description

In order that the utility model may be readily understood, a more complete description of the utility model will be rendered by reference to the appended drawings. The drawings illustrate preferred embodiments of the utility model. This utility model may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "top," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 2, an embodiment of the utility model discloses a carbon electric forging furnace system with a novel power supply mode, which comprises a carbon electric forging furnace, a primary winding 100 of a transformer, a secondary winding 200 of the transformer, a bidirectional thyristor 300 and a diode 400, wherein:

the input end of the primary winding 100 of the transformer is respectively connected with the output end of the bidirectional thyristor 300, the input end of the bidirectional thyristor 300 is connected with a three-phase power supply, the output end of the secondary winding 200 of the transformer is respectively connected with the anode of the diode 400, the cathode of the diode 400 is connected with the direct current bus 500, and the direct current bus 500 is connected with the carbon electric forging furnace.

The rectifying circuit in the carbon electric forging furnace system is technically improved, the original Y/[ delta ] connection method is improved to a three-phase five-column double-inverse-star six-pulse wave rectifying power supply mode, the primary side is subjected to voltage regulation, the secondary side is subjected to rectification, namely, a bidirectional thyristor is additionally arranged on the primary side of a transformer, and the secondary side adopts two groups of three-phase half-wave rectifying circuits to output six-pulse direct current power supplies in parallel, so that the balancing reactor in the traditional alternating current voltage regulating circuit is omitted, the circuit structure is simplified, the volume of rectifying equipment is reduced, the direct current component is increased, the power factor is increased by more than 90%, the operation loss is smaller, the short-network power supply is realized for the carbon electric forging furnace, the operation quality of a power grid is greatly improved, the power utilization efficiency is improved, the advantages of green energy conservation are embodied, and the energy-saving effect is obvious. Through theoretical operation and actual operation verification, the utility model regulates voltage at the primary side, while the traditional power supply regulates voltage at the secondary side of the transformer, and under the condition of the same load, the current of the former is small, and the loss of the transformer is small; the utility model adopts a double-inverse star connection method, and the transformer of the traditional power supply adopts a Y/delta connection method, and the leakage reactance of the former transformer does not influence the commercial power, so the harmonic wave is small, and the power factor is high; in each cycle (20 ms), the average on time of each diode 400 in the utility model is 6.7ms, and the on time of each thyristor in the traditional power supply is also 6.7ms, but the current value of the former is twice smaller than that of the latter, so the heat loss is small, and the heat dissipation is facilitated.

Because the three-phase five-column transformer is adopted, two side yokes provide a passage for the triple frequency harmonic magnetic flux or the zero sequence magnetic flux in the asymmetric component, the additional loss is greatly reduced, the power consumption of the secondary side rectifying element is reduced, and the rectifying efficiency is improved. Meanwhile, reactive components are reduced, active components are increased, and the power factor is improved. In addition, the bidirectional thyristor 300 is adopted to replace a balance reactor, and the controllable characteristic of the bidirectional thyristor 300 can be utilized to automatically adjust the input voltage. The operation process of the carbon electric forging furnace is kept in the optimal working condition on the optimal temperature rising curve. Meanwhile, the bidirectional thyristor 300 is controlled by a digital circuit, and has higher stability, accuracy and precision than an analog control circuit, and strong anti-interference performance.

In an alternative embodiment, the triac 300 may include a ring circuit and two unidirectional thyristors disposed on the ring circuit, with the input and output terminals of the triac 300 being disposed between the unidirectional thyristors, and the two unidirectional thyristors being turned on in opposite directions in a direction in which the input terminal of the triac 300 is directed toward the output terminal thereof. In particular, the unidirectional thyristor may be a cathode controlled unidirectional thyristor.

Of course, in an alternative embodiment, triac 300 may be a triac.

Specifically, the transformer secondary winding 200 has the structure: u and u 'are wound on a phase iron core, v and v' are wound on a phase iron core, w and w 'are wound on a phase iron core, and two groups of three-phase half-wave rectification circuits are formed, wherein u, v and w are positive groups u', v 'and w' are reverse groups.

Compared with the prior art, the technical scheme in the utility model and the technical scheme in the prior art are analyzed and compared as follows.

1. Energy loss analysis and comparison

As can be seen from the volt-ampere characteristic of the diode 400, the current flowing through the diode 400 increases exponentially with the voltage drop at the time of conduction, and thus the large voltage drop of the diode 400 during conduction is taken as the calculated value.

(1) In fig. 1 (prior art solution), the on average current of the thyristor is 2000A, the on peak voltage is 2.6V, and at any time, the power consumption is p=ui=2.6x2000×2=10400 (W); the fuse selects rated current 2000A, loss is less than 110W, and the loss takes a large value of 110W. The total loss of fig. 1 is p=10400+110×2=10620 (W).

(2) In fig. 2 (the embodiment of the present utility model), the on average current of the diode 400 is 2000A, the on peak voltage is 1.7V, and at any time, the power consumption is: p=ui=1.7×1360=2312 (W); the thyristor has an on average current of 300A, an on peak voltage of 2.3V, and at any one time, the power consumption is p=ui=2.3×300×2=1380 (W); the rated current of the fuse is less than 160A, the loss is less than 12W, and the loss is larger than 12W.

The total heat loss of fig. 2 is p=2312+1308+12×3=3656 (W). Segmentation it can be seen from the above derivation that the loss of figure 1 is about 3 times that of figure 2.

2. Loss analysis of transformers

The loss of the transformer is related to the selected ferromagnetic material and manufacturing process, and also related to the magnitude of the primary side input voltage, the load magnitude, the frequency magnitude and other factors. Assuming that all conditions are ideal except the transformer, the power components have no loss, alpha=30°, gamma=0, the current and voltage are stable, and the direct current resistance of the transformer winding is the same, the loss of the transformer comprises two parts, namely copper loss and iron loss.

(1) Copper losses include basic copper losses, which are caused by the direct current resistance of the winding, which is equal to the product of the square of the current and the direct current resistance, and additional copper losses; the additional copper loss includes copper loss increased by the skin effect caused by the leakage magnetic field to increase the effective resistance of the wires, loss of internal circulation when a plurality of wires are wound in parallel, and the like. The additional copper loss, like the basic copper loss, is proportional to the square of the load current. The additional copper losses are difficult to calculate accurately, so they can be considered to be about 0.5% to 5% of the basic copper losses.

The secondary winding u-phase voltages u ' of fig. 2 are 180 ° apart, v and v ', w and w ', so the currents are 180 ° apart, and their magnitudes are equal. Taking any phase as an example, although the occurrence time of the phase currents iu and iu' is different, the average value is i/6, the average currents are equal and the winding polarities are opposite, so that the direct current ampere turns are mutually offset, and the direct current magnetomotive force is eliminated. At any one time, two diodes are on, and the average current through each diode 400 is i/2, so at any one time, the basic copper loss is P _cu ＝i/2×i/2×R×2＝i×i×R/2＝1360×1360R/2＝924800R(W)。

The common cathode set of fig. 1 is conducting in the positive half-cycle, the common anode is conducting in the negative half-cycle, and there is no dc magnetomotive force in the transformer windings. At any one time, two thyristors are turned on, and the average current through each thyristor is i, so that at any one time, the basic copper loss is P _cu =i×i×r×2=1240×1240×r×2= 3075200R (W). The basic copper loss of fig. 1 is about 3.29 times that of fig. 2.

(2) The iron loss also comprises basic iron loss and additional iron loss, wherein the basic iron loss is hysteresis loss and eddy current loss in the transformer core and is approximately proportional to the square of the once measured input voltage; the additional iron loss is mainly caused by the manufacturing process and is approximately proportional to the input voltage, and is difficult to calculate accurately, and is typically 15% -20% of the basic iron loss. The basic iron loss of FIG. 2 is P _fe =u×u/r=47.5×47.5/r= 2256.25/R (W); the basic iron loss of FIG. 1 is P _fe =u×u/r=380×380/r= 144400/R (W). The basic iron loss of fig. 1 is about 64 times that of fig. 2.

3. Harmonic and power factor analysis

In the above deduction, the leakage inductance of the transformer is ignored, but in practice, the leakage inductance is always present on the winding of the transformer, so that the current suddenly drops from I to 0, or the current rises from 0 to I, and the current commutation is not completed instantaneously after a period of time. Therefore, the period of time corresponding to the commutation process is represented by the commutation overlap angle γ. It is assumed that the leakage reactance Xb converted to the secondary measurement for each phase of the two transformers is equal.

The formula for fully controlled rectification in fig. 1: cos α -cos (α+γ2) =2×i _d X _B /2.449×U ₂

The uncontrollable rectification formula in fig. 2 is:

cosα+cos(α+γ1)＝1.414×I _d X _B /U ₂

substituting α=0, then (1-cos γ2)/(1-cos γ1) = 3.464

From the above equation, γ2> γ1 is calculated, i.e., the overlap angle of fig. 1 is larger than that of fig. 2. The larger the overlapping angle is, the deeper the phase voltage waveform is notched, the more serious the waveform distortion of the power grid is caused, the power factor of the rectifying device is reduced, and the voltage pulsation coefficient is increased. On the contrary, the technical scheme of the utility model has smaller overlapping angle, shallower notch, smaller influence on waveform distortion of the power grid, greatly improved running quality of the power grid, improved power utilization efficiency, larger power factor of the rectifying circuit and reduced voltage pulsation coefficient.

4. Analysis and comparison of technical characteristics of two pressure regulating modes

The three-phase five-column-core type transformer direct current voltage regulating power supply regulates voltage at the primary side of the transformer, the traditional power supply regulates voltage at the secondary side of the transformer, and under the condition of the same load, the current of the former is small, and the loss of the transformer is small. In the utility model, the transformer adopts a double-inverse star connection method, while the transformer of the traditional power supply adopts a Y/[ delta ] connection method, and the leakage reactance of the former transformer does not influence the commercial power, so the harmonic wave is small, and the power factor is high. In each cycle (20 ms), the average conduction time of each diode of the five-pole-core type transformer direct-current voltage-regulating power supply is 6.7ms, and the conduction time of each thyristor of the traditional power supply is also 6.7ms, but the current value of the five-pole-core type transformer direct-current voltage-regulating power supply is twice smaller than that of the traditional power supply, so that the heat loss is small, and the heat dissipation is facilitated. The fuse mounting positions are different, and the heat losses are also different, and the former current is much smaller than the latter current according to q=i×i×r×t, so the heat losses are also much smaller. The digital control circuit is adopted in the utility model, which is obviously higher than the stability, the accuracy and the precision of the analog circuit regulated by PID, and has strong anti-interference performance.

In summary, the three-phase five-column core type variable-voltage rectifying circuit is adopted in the utility model, so that the controllable voltage regulation is carried out on the primary side of the transformer, and compared with the traditional alternating-current voltage regulating power supply, the direct-current adjustable power supply with uncontrollable rectification on the secondary side has the advantages of high power factor and remarkable energy-saving effect, and the electric power cost of enterprises is effectively saved.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims (5)

1. The utility model provides a carbon electric forging furnace system with novel power supply mode, its characterized in that includes carbon electric forging furnace, transformer primary winding (100), transformer secondary winding (200), bidirectional thyristor (300) and diode (400), the input of transformer primary winding (100) respectively with the output of bidirectional thyristor (300) links to each other, the input of bidirectional thyristor (300) links to each other with three-phase power, the output of transformer secondary winding (200) respectively with the positive pole of diode (400) links to each other, the negative pole of diode (400) is connected with direct current busbar (500), direct current busbar (500) with carbon electric forging furnace is connected.

2. The carbon electric forging furnace system with the novel power supply mode according to claim 1, wherein the bidirectional thyristor (300) comprises a ring circuit and two unidirectional thyristors arranged on the ring circuit, an input end and an output end of the bidirectional thyristor (300) are arranged between the two unidirectional thyristors, and in the direction that the input end of the bidirectional thyristor (300) points to the output end of the bidirectional thyristor, the conducting directions of the two unidirectional thyristors are opposite.

3. The carbon electric forging furnace system with a novel power supply mode according to claim 2, wherein the unidirectional thyristor is a cathode controlled unidirectional thyristor.

4. The carbon electric forging apparatus system with novel power supply mode as recited in claim 1, wherein said triac (300) is a triac.

5. The carbon electric forging furnace system with novel power supply mode as recited in claim 1, wherein the secondary winding (200) of the transformer has the structure that: u and u 'are wound on a phase iron core, v and v' are wound on a phase iron core, w and w 'are wound on a phase iron core, and two groups of three-phase half-wave rectification circuits are formed, wherein u, v and w are positive groups u', v 'and w' are reverse groups.