CN217388549U

CN217388549U - 750V incoming line series resonance intermediate frequency power supply device

Info

Publication number: CN217388549U
Application number: CN202221058560.9U
Authority: CN
Inventors: 李小军
Original assignee: Hubei Kerui Electric Co ltd
Current assignee: Hubei Kerui Electric Co ltd
Priority date: 2022-04-28
Filing date: 2022-04-28
Publication date: 2022-09-06
Anticipated expiration: 2032-04-28

Abstract

The utility model discloses a 750V inlet wire series resonance intermediate frequency power supply unit relates to the firing equipment power technology, has solved the silicon controlled rectifier in its rectifier circuit behind the intermediate frequency power supply unit lifting voltage and has leaded to its technical problem who is punctured because of peak voltage is too high easily. The medium-frequency power supply device comprises a rectifying circuit consisting of six rectifying thyristors, an inverter circuit consisting of two inverter bridge arms and a high-voltage transformer with output voltage of 750VAC three-phase power; and a filtering unit is connected between the cathode and the anode of each rectification silicon controlled rectifier, the output end of each rectification circuit is connected with a follow current unit and a first filtering capacitor which are connected in parallel, and a smoothing reactor is connected between the follow current unit and the first filtering capacitor. The utility model discloses not only reduced the cable in the electric current, reduced its calorific capacity, can also reach the purpose of protection silicon controlled rectifier, fine assurance the normal operating of circuit.

Description

750V incoming line series resonance intermediate frequency power supply device

Technical Field

The utility model relates to a heating equipment power technology, more specifically say that it relates to 750V inlet wire series resonance intermediate frequency power supply unit.

Background

The medium frequency power supply is a static frequency conversion device, can convert three-phase power into single-phase power, and is very important equipment in the industries of casting, heat treatment and the like. The current intermediate frequency power supplies are classified into series resonance intermediate frequency power supplies and parallel resonance intermediate frequency power supplies.

As shown in fig. 1, the conventional series resonant if power supply includes a rectifying circuit composed of a plurality of thyristors and an inverting circuit composed of a resonant capacitor and thyristors. The controllable silicon is controlled by a controller. When 380VAC power frequency voltage at the incoming line end of the circuit part of the intermediate frequency power supply device is rectified by the rectifying circuit, the rectified voltage is about 510V.

However, with the increase of the required power of the equipment, the conventional three-phase power is still adopted, the current of the power is increased, the heating of the cable is abnormal, and the long-term use is not facilitated. Because the inlet wire part of intermediate frequency power supply unit is generally buried ground and is handled, the great manpower and financial resources of cost are obviously difficult to carry out to the transformation part. If the voltage of the incoming line end of the medium-frequency power supply is increased and parameters of electronic components in the medium-frequency power supply are adjusted, the problem of abnormal heating of the cable caused by current increase can be solved. However, the voltage of the rectifying part and the inverting part of the intermediate frequency power supply is increased due to the increase of the voltage of the incoming line terminal, so that the peak voltage generated when the intermediate frequency power supply rectifies an electric signal is higher, and the breakdown of rectifying silicon controlled rectifier is very easy to cause, and the intermediate frequency power supply device needs to be maintained frequently.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is not enough to prior art, provide 750V inlet wire series resonance intermediate frequency power supply unit, solved the silicon controlled rectifier in its rectifier circuit behind the intermediate frequency power supply unit lifting voltage and leaded to its problem of being punctured because of peak voltage is too high easily.

The utility model relates to a 750V incoming line series resonance intermediate frequency power supply device, which comprises a rectification circuit mainly composed of six rectification silicon controlled rectifiers and an inversion circuit mainly composed of a first inversion bridge arm and a second inversion bridge arm which are arranged in a crossed manner; the first inversion bridge arm comprises a second resonant capacitor and k inversion controllable silicon; the second inversion bridge arm comprises a third resonant capacitor and k inversion controllable silicon; two output ends of the rectifying circuit are respectively connected with input ends of two inverter bridge arms in a one-to-one correspondence manner, and a common end of the two inverter bridge arms is connected with an inductor; the intermediate frequency power supply device also comprises a high-voltage transformer with the output voltage of 750 VAC; the output end of the high-voltage transformer is connected with the input end of the rectifying circuit through a protection unit, a filtering unit is connected between the cathode and the anode of each rectifying silicon controlled rectifier, the output end of the rectifying circuit is connected with a follow current unit and a first filtering capacitor which are connected in parallel, and a smoothing reactor is connected between the follow current unit and the first filtering capacitor;

wherein k is a natural number of 1 or more.

The filtering unit consists of an i1 resistor and an i1 capacitor which are connected in series;

wherein i is any natural number from 1 to 6.

The freewheel unit is composed of a diode or a plurality of diodes connected in series.

The protection unit consists of a leakage protection switch and a fuse which are connected in series.

The rectification silicon controlled rectifier adopts a flat plate type silicon controlled rectifier.

The inversion controllable silicon adopts a flat plate type controllable silicon.

Advantageous effects

The utility model has the advantages that: through the arrangement of the filter unit, the first filter capacitor, the follow current unit and the smoothing reactor, peak voltage generated during the operation of the rectifier silicon controlled rectifier is effectively absorbed, so that the aims of absorbing the peak voltage and protecting the silicon controlled rectifier are fulfilled, and the normal operation of a circuit is well ensured.

Drawings

Fig. 1 is a schematic circuit diagram of a conventional intermediate frequency power supply device;

FIG. 2 is a schematic diagram of a circuit connection structure of the high voltage transformer and the rectifying circuit of the present invention;

fig. 3 is a schematic diagram of the inverter circuit structure of the present invention.

Detailed Description

The present invention will be further described with reference to the following examples, which are not intended to limit the scope of the present invention, but are intended to be covered by the appended claims in any way.

The utility model discloses a 750V inlet wire series resonance intermediate frequency power supply unit, include the rectifier circuit that comprises six rectification silicon controlled rectifiers and the inverter circuit who comprises first contravariant bridge arm and the second contravariant bridge arm of cross arrangement.

A rectifier circuit. The six rectification silicon controlled rectifiers forming the rectification circuit are respectively a first rectification silicon controlled rectifier V1, a second rectification silicon controlled rectifier V2, a third rectification silicon controlled rectifier V3, a fourth rectification silicon controlled rectifier V4, a fifth rectification silicon controlled rectifier V5 and a sixth rectification silicon controlled rectifier V6. In addition, the rectifying circuit further includes a first filter capacitor C1. The circuit structure is shown in fig. 1, a first rectifying silicon controlled rectifier V1, a third rectifying silicon controlled rectifier V3 and a fifth rectifying silicon controlled rectifier V5 share a cathode, and a second rectifying silicon controlled rectifier V2, a fourth rectifying silicon controlled rectifier V4 and a sixth rectifying silicon controlled rectifier V6 share an anode. After the 750VAC three-phase power output by the high-voltage transformer T1 passes through the rectification silicon controlled rectifier, the common cathode of the rectification silicon controlled rectifier obtains a positive voltage signal, and the common anode of the rectification silicon controlled rectifier obtains a negative voltage signal. The above description of the rectifier circuit is prior art and the present invention is not an improvement thereof.

The intermediate frequency power supply apparatus further includes a high voltage transformer T1 having an output voltage of 750 VAC. The output end of the high-voltage transformer T1 is connected with the input end of the rectifying circuit through the protection unit. The input current of the transformer is reduced when the input voltage is increased under the same power according to a power calculation formula, so that the aims of reducing the current in the cable and reducing the heat productivity of the cable are fulfilled, and the equipment can be normally used without line change.

It should be noted that, the high voltage transformer T1 with an output voltage of 750VAC is an existing product and can be obtained through a purchased channel, and the present invention does not improve the existing product.

Preferably, the protection unit is composed of a leakage protection switch K1 and a fuse FU connected in series. The earth leakage protection switch K1 and the fuse FU play a role in protecting the intermediate frequency power supply device.

The increase in the input voltage of the rectifier circuit entails a further increase in the peak voltage. To solve this problem, a filter unit is connected between the cathode and the anode of each of the rectifier thyristors in this embodiment. Through the filtering effect of the filtering unit, peak voltage appearing at two ends of the rectifying silicon controlled rectifier can be effectively filtered, and the effect of protecting the rectifying silicon controlled rectifier is achieved.

As shown in fig. 2, the filtering unit is composed of an i1 th resistor Ri1 and an i1 th capacitor Ci 1. Wherein i is any natural number from 1 to 6. The filter unit consisting of the resistor and the capacitor is easy to realize and low in cost.

In addition, a freewheeling unit and a first filter capacitor C1 are connected between the common cathode and the common anode in the rectifying circuit. Wherein the freewheel unit is composed of one diode or a plurality of diodes connected in series. In this embodiment, a first diode D1 is used, and the cathode of the first diode D1 is connected to the common cathode. The first diode D1 functions as a free-wheeling. If a follow current unit consisting of a plurality of diodes is adopted, the anodes and the cathodes of the plurality of diodes are sequentially connected in series, the cathode of the diode positioned at one end of the follow current unit is connected with the common cathode, and the anode of the diode positioned at the other end of the follow current unit is connected with the common anode.

A smoothing reactor L0 is further connected between the cathode of the first diode D1 and the first filter capacitor C1 and is used for filtering the electric signal rectified by the rectifying silicon controlled rectifier, and clutter signals in the electric signal can be effectively reduced.

As shown in fig. 3, for an inverter circuit. A first inversion bridge arm in the inversion circuit comprises a second resonant capacitor C2 and k inversion thyristors. The second inversion bridge arm comprises a third resonant capacitor C3 and k inversion thyristors. And the inversion controllable silicon in the first inversion bridge arm is marked as the mth inversion controllable silicon Vm, and the inversion controllable silicon in the second inversion bridge arm is marked as the nth inversion controllable silicon Vn. Wherein k is a natural number of 1 or more; n is a double number of 8 or more; m is the singular of 9 or more. Two output ends of the rectifying circuit are respectively connected with input ends of two inverter bridge arms in a one-to-one correspondence mode, and a common end of the two inverter bridge arms is connected with an inductor L5.

In order to ensure that the inversion thyristors are not easily integrated by peak voltage and can work effectively and safely, the anode of each nth inversion thyristor Vn is connected with a first resistance-capacitance absorption unit, and the cathode of each mth inversion thyristor Vm is connected with a second resistance-capacitance absorption unit.

The first resistance-capacitance absorption unit comprises an n1 th resistor Rn1, an n2 th resistor Rn2, an n1 th diode Dn1, an n2 th diode Dn2 and an n1 th capacitor Cn 1. The anode of the n1 th diode Dn1 is connected to the anode of the n-th inverter thyristor Vn, the cathode of the n1 th diode Dn1 is connected to one end of an n1 th capacitor Cn1 through an n1 th resistor Rn1, the other end of the n1 th capacitor Cn1 is connected to the anode of an n2 th diode Dn2, the cathode of the n2 th diode Dn2 is connected to the anode of the n-th inverter thyristor Vn, the connection end of the n1 th capacitor Cn1 and the n1 th resistor Rn1 is connected to the anode of the n-th inverter thyristor Vn through an n2 th resistor Rn2, and the anode of the n2 th diode Dn2 is also connected to the cathode of the n-th inverter thyristor Vn.

The second resistance-capacitance absorption unit comprises an m1 resistor Rm1, an m2 resistor Rm2, an m1 diode Dm1, an m2 diode Dm2 and an m1 capacitor Cm 1; the cathode of the m1 th diode Dm1 is connected to the cathode of the m-th inverter thyristor Vm, the anode of the m1 th diode Dm1 is connected to one end of an m1 capacitor Cm1 through an m1 th resistor Rm1, the other end of the m1 th capacitor Cm1 is connected to the cathode of the m2 th diode Dm2, the anode of the m2 th diode Dm2 is connected to the cathode of the m-th inverter thyristor Vm, the connection end of the m1 th capacitor Cm1 and the m1 th resistor Rm1 is connected to the cathode of the m-th inverter thyristor Vm through an m2 th resistor Rm2, and the cathode of the m2 th diode Dm2 is further connected to the anode of the m-th inverter thyristor Vm.

In the embodiment, the resistance-capacitance absorption unit is additionally arranged on the inversion controllable silicon, and the resistance-capacitance absorption unit is used for absorbing the peak voltage generated when the bridge arm works, so that the aims of absorbing the peak voltage and protecting the controllable silicon are achieved, and the normal operation of the circuit is well ensured.

Preferably, the cathode of the nth inverter thyristor Vn is connected to one end of the inductor L5 through the nth filter inductor Ln. The anode of the mth inverting thyristor Vm is connected to one end of the inductor L5 through the mth filtering inductor Lm. The risk that the inversion silicon controlled rectifier is punctured can be further reduced through the filtering effect of the filter inductor.

In this embodiment, the rectifying thyristors and the inverting thyristors are both flat thyristors.

What has been described above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make a plurality of modifications and improvements without departing from the structure of the present invention, and these will not affect the effect of the present invention and the practicability of the patent.

Claims

The 1.750V inlet wire series resonance intermediate frequency power supply device comprises a rectifying circuit mainly composed of six rectifying silicon controlled rectifiers and an inverter circuit mainly composed of a first inverter bridge arm and a second inverter bridge arm which are arranged in a crossed mode; the first inversion bridge arm comprises a second resonant capacitor and k inversion controllable silicon; the second inversion bridge arm comprises a third resonant capacitor and k inversion controllable silicon; two output ends of the rectifying circuit are respectively connected with input ends of two inverter bridge arms in a one-to-one correspondence manner, and a common end of the two inverter bridge arms is connected with an inductor; the medium frequency power supply device is characterized by also comprising a high-voltage transformer with the output voltage of 750 VAC; the output end of the high-voltage transformer is connected with the input end of the rectifying circuit through a protection unit, a filtering unit is connected between the cathode and the anode of each rectifying silicon controlled rectifier, the output end of the rectifying circuit is connected with a follow current unit and a first filtering capacitor which are connected in parallel, and a smoothing reactor is connected between the follow current unit and the first filtering capacitor;

wherein k is a natural number of 1 or more.
2. The 750V incoming line series resonance intermediate frequency power supply device of claim 1, characterized in that said filter unit is composed of an i1 th resistor and an i1 th capacitor connected in series;

wherein i is any natural number from 1 to 6.
3. A 750V incoming line series resonant if power supply device according to claim 1, characterized in that said freewheel unit consists of one diode or a plurality of diodes connected in series.
4. The 750V incoming line series resonance intermediate frequency power supply device of claim 1, characterized in that said protection unit is composed of a leakage protection switch and a fuse connected in series.
5. The 750V incoming line series resonance intermediate frequency power supply device according to claim 1, wherein said rectifying thyristors are flat type thyristors.
6. The 750V incoming line series resonance intermediate frequency power supply device of claim 1, wherein said inverter thyristors are flat thyristors.