CN217824752U - Circuit layout structure of frequency converter - Google Patents

Abstract

A circuit layout structure of a frequency converter comprises a rectifying unit, a power conversion unit, a direct current bus unit, a control single board, a wiring terminal and a heat dissipation unit; the rectifying unit and the power conversion unit are arranged above the heat dissipation unit, and the direct current bus unit is divided into two parts which are respectively positioned on the upper surface and the lower surface of the power conversion unit; the control single board is positioned above the direct current bus unit on the upper surface of the power conversion unit; a wiring terminal is arranged on the side surface of the direct current bus unit on the upper surface of the power conversion unit; the utility model discloses an optimize direct current unit layout structure, reduce the parasitic inductance between direct current bus unit and the PIM to reach the purpose that reduces whole parasitic inductance. The scheme does not increase the cost, directly shortens the distance between the direct current unit and the inversion unit through the layout, namely optimizes the parasitic inductance, effectively reduces the overall parasitic inductance of the system and solves the voltage stress problem of response.

Description

Circuit layout structure of frequency converter

Technical Field

The utility model belongs to the technical field of the converter, in particular to converter circuit layout structure.

Background

In a typical application scheme of a frequency converter product, after power grid input, power frequency alternating current is converted into direct current through a rectification unit power supply, energy buffering is performed through a direct current bus unit circuit, and then the direct current voltage is converted into variable-frequency alternating voltage through an inverter unit circuit for frequency conversion and speed regulation operation at a motor end. Wherein, the inverter unit circuit mainly has two types of devices to choose from: namely a separated device IGBT tube which is mainly used for medium and high power section frequency conversion speed regulation products; an Integrated device PIM (Power Integrated Module) is mainly used for compact and low-Power section variable frequency speed regulation products.

The patent discusses: an inverter circuit layout structure scheme adopting PIM devices.

The PIM device integrates the required IGBT into a whole power module, and the development and assembly of a complete variable frequency speed regulation device can be realized only by designing and welding a corresponding control circuit, a direct current bus circuit and a rectifying circuit at the periphery. The application of the IGBT chip in the PIM has the range limitation of voltage stress, and once the voltage between pins of the chip exceeds the limit value of the chip, irreversible damage can be caused. The factors influencing this voltage are mainly caused by the parasitic inductance in the circuit (the basic principle is lenz's law, which is not described here), and the parasitic inductance of the circuit comes from two parts:

(1) Inside various component units: PIM inside, rectifying unit inside, bus unit (capacitor) inside; this section

Once the parasitic inductance is selected and can not be changed, the parasitic inductance of the part

The occupation ratio is small;

(2) Among various types of device units: connecting circuit portions between the partial units, e.g. PCB wiring paths,

A cable loop area; the part has a large degree of relation with the structure layout, and the inductance of the parasitic inductance of the part accounts for a large amount, so that the performance of the voltage stress of the IGBT can be obviously influenced.

In current frequency converter products, because the volume structure, the power requirement and the like are relatively standardized, the two factors influencing the parasitic inductance in the analysis are basically introduced into the products.

(1) The class influence factors are difficult to directly optimize due to the fact that the class influence factors are limited by the device, and influence is weak due to small occupation ratio;

(2) Class influence factors depend on objective engineering conditions such as actual product size and structural layout conditions; the problem that the voltage stress of the IGBT exceeds the standard due to larger parasitic inductance often occurs, and the problem is solved by adding an absorption capacitor under the current common condition; namely, by adding the capacitor, the voltage spike generated by the parasitic inductance is suppressed by the voltage stabilizing effect of the capacitor on the voltage, and the parasitic inductance is not directly reduced. The problems with this solution are:

(1) The cost and the volume are increased;

(2) Introducing one device more brings one fault point;

(3) Due to different layouts of products and difference of parasitic inductance and inductance, the matched absorption capacitance capacity and the matched structure size are different, normalization and standardization are difficult to realize, and the difficulty in developing and selecting models is increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a converter circuit layout structure to solve above-mentioned problem.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a frequency converter circuit layout structure comprises a rectifying unit, a power conversion unit, a direct current bus unit, a control single board, a wiring terminal and a heat dissipation unit; the rectifying unit and the power conversion unit are arranged above the heat dissipation unit, and the direct current bus unit is divided into two parts which are respectively positioned on the upper surface and the lower surface of the power conversion unit; the control single board is positioned above the direct current bus unit on the upper surface of the power conversion unit; a wiring terminal is arranged on the side surface of the direct current bus unit on the upper surface of the power conversion unit; the wiring terminal is connected to the rectifying unit, the rectifying unit is connected to the direct current bus unit, the power conversion unit is also connected to the direct current bus unit, and the alternating current end of the power conversion unit is connected to the wiring terminal.

Further, the direct current bus unit comprises a first direct current bus unit and a second direct current bus unit; the first direct current bus unit is located on the lower surface of the power conversion unit, and the second direct current bus unit is located on the upper surface of the power conversion unit.

Furthermore, the first direct current bus unit and the second direct current bus unit are formed by connecting electrolytic capacitors in series and in parallel.

Furthermore, the +, -pole of the capacitor of the first direct current bus unit is directly welded on the DC + and DC-pin of the power conversion unit; and the capacitor of the second direct current bus unit is positioned in the heat dissipation unit space, and the capacity of the capacitor of the second direct current bus unit is 3/4 of the whole capacity.

Furthermore, the power conversion unit is attached to the heat dissipation unit.

Further, the heat dissipation unit comprises a radiator and a heat dissipation fan, and the heat dissipation fan is arranged on the side face of the radiator.

Furthermore, the rectifying unit, the power conversion unit, the direct current bus unit, the control single board, the wiring terminal and the heat dissipation unit are all arranged in the shell of the frequency converter.

Further, cooling fan sets up on the converter casing.

Compared with the prior art, the utility model discloses there is following technological effect:

the utility model provides a converter circuit layout structure scheme does not increase under the prerequisite of device (absorption capacitance), through optimizing direct current unit layout structure, reduces the parasitic inductance between direct current bus unit and the PIM to reach the purpose that reduces whole parasitic inductance. The scheme does not increase the cost, directly shortens the distance between the direct current unit and the inversion unit through the layout, namely optimizes the parasitic inductance, effectively reduces the overall parasitic inductance of the system and solves the voltage stress problem of response.

Based on the problem and the demand of solving parasitic inductance in the present converter product, this patent provides a circuit layout structure scheme. According to the scheme, on the premise that a device (absorption capacitor) is not added, the direct current bus unit is split into two parts by optimizing the layout structure of the direct current bus unit, and the parasitic inductance between the direct current bus unit and the PIM is effectively reduced according to the energy required by the switching process (the process of generating the voltage stress of the parasitic inductance) of the PIM and the steady-state operation process of the PIM, so that the aims of reducing the overall parasitic inductance and effectively solving the problem of voltage spike generation are fulfilled.

The scheme does not increase the cost, directly shortens the distance between the direct current unit and the inversion unit through the layout, namely optimizes the parasitic inductance, effectively reduces the overall parasitic inductance of the system and solves the voltage stress problem of response. The method has the advantages of no increase of cost and failure risk points, and certain general effect, and is beneficial to normalized design.

Drawings

FIG. 1 shows the internal layout of a frequency converter;

FIG. 2 is an enlarged view of a portion of the frequency converter;

FIG. 3 is an enlarged view of a portion of the frequency converter;

Detailed Description

The invention is further described below with reference to the accompanying drawings:

the utility model provides a converter circuit layout structure scheme. The solution is directed to solving the problem of parasitic inductance in the frequency converter product by adding a solution of absorption capacitance, and the solution avoids adverse effects brought by the conventional solution while solving the problem.

The scheme provides a novel layout structure of the internal circuit structure of the frequency converter, and the circuit structure and the circuit connection relation effectively solve the problem that the electrical stress exceeds the standard due to the parasitic inductance of the internal circuit of the frequency converter on the premise of not newly introducing a device (namely, the product cost is not increased). The frequency converter component mainly comprises: the power conversion module comprises a rectifying unit 1, a power conversion unit (PIM IGBT) 2, a first direct current bus unit 3, a second direct current bus unit 4, a control single board (comprising an operation panel) 5, a wiring terminal 6, a heat dissipation fan 7, a radiator 8 and the like.

Describing according to a power trend path: after power is taken from a power grid, the power is connected to a rectifying unit through an input wiring terminal, the output of the rectifying unit is a direct current signal, the direct current signal is connected to a direct current bus unit (realized by an electrolytic capacitor series-parallel connection mode) to form DC & lt + & gt and DC & lt- & gt, meanwhile, a direct current end of a power conversion unit (PIM IGBT) is also connected to the DC & lt + & gt and DC & lt- & gt, and an alternating current end of the power conversion unit is connected to a load through an output wiring terminal and a copper bar (or a cable). The sensor (current) is of a straight-through structure and is sleeved on the output copper bar or the cable.

Describing according to the structural layout: the frequency converter is respectively a radiator, a heat radiation fan and a first direct current bus unit 3 from bottom to top, the rectifying unit and the power conversion unit are attached to the radiator, the middle part is a part of a second direct current bus unit 4, a sensor (current) and an input/output copper bar, and the upper part is a control single plate.

The key points of the patent scheme are as follows: the direct current bus unit (PCB assembly connected in series-parallel by electrolytic capacitors) is split into 2 parts, the plus and minus poles of the 1 st part of capacitor are directly welded on DC + and DC-pins right above the PIM module, the capacity of the part is about 1/4 of the capacity of the integral bus of the frequency converter, and the capacity of the part correspondingly provides energy required by the IGBT tube in the PIM in a switching state (usually tens to hundreds of ns level); the 2 nd part of the capacitor is positioned in the front end heat dissipation cabin space of the frequency converter product, the capacity of the part of the capacitor is 3/4 of the whole capacity, and the capacity of the part of the capacitor provides the energy requirement (usually in the order of ms) in the continuous conduction state of the IGBT. The voltage stress problem caused by parasitic inductance factors occurs at the turn-off time of the IGBT; at this time, the parasitic inductance in the circuit operation process is a main aspect of the problem, and the capacitance of the part 1 in the scheme is obviously shorter than that of the part 2 due to the fact that the path between the capacitance and the PIM (IGBT) is obviously shorter, and the provided energy can meet the switching requirement of the IGBT, so that the scheme is an effective scheme; meanwhile, when the IGBT tube enters a steady state and is continuously conducted after the IGBT tube is switched on and off, no voltage spike exists, the required energy is borne by the 2 nd part, and the requirement of steady state output is met. Meanwhile, a new fault risk point is not introduced in the scheme; has certain common effect and is beneficial to the normalized design of products.

As shown in fig. 1, the internal components of the frequency converter include:

1. a rectifying unit: after power is taken from a power grid, power frequency alternating current-direct current conversion is realized;

2. PIM (IGBT): the integrated inverter circuit unit in frequency converter product can implement DC-AC (frequency conversion) conversion

3. Direct current bus bar unit component 1: energy source for PIM (IGBT) in steady state continuous conduction state

4. Direct current bus bar unit component 2: energy source for PIM (IGBT) on-off state

5. Controlling the single board: signal processing, logic operation and control software operation in frequency converter

6. Connecting terminal: the input terminal is connected with the power grid, and the output terminal is connected with the load

7. A heat radiation fan: blowing cold air into the converter after rotating to dissipate heat of a part of a cold source of the converter, so as to dissipate heat of a heating component;

8. a radiator: the heat dissipation cold source is part of the heat dissipation cold source of the frequency converter;

2. as shown in fig. 2, the dc bus bar unit 2

Dc bus bar unit component 2: the energy source is used in a PIM (IGBT) switching state and is directly welded and installed right above the PIM, so that the minimum loop area in the circuit operation process is ensured, and the voltage spike steady state caused by parasitic inductance is effectively saved;

3. as shown in FIG. 3, a DC bus bar unit 1

Direct current bus bar unit component 1: the energy source is used for an energy source in a stable continuous conduction state of PIM (IGBT), the process is a stable working condition with a large time constant, so that the requirement on the loop area of line operation is not high, and the PIM can be properly principle; however, the operation time constant is large, so that the heat dissipation device needs to be placed in the air duct for effective heat dissipation.

Claims (8)

1. A frequency converter circuit layout structure is characterized by comprising a rectifying unit (1), a power conversion unit (2), a direct current bus unit, a control single board (5), a wiring terminal (6) and a heat dissipation unit; the rectifying unit (1) and the power conversion unit (2) are arranged above the heat dissipation unit, and the direct current bus unit is divided into two parts which are respectively positioned on the upper surface and the lower surface of the power conversion unit (2); the control single board (5) is positioned above the direct current bus unit on the upper surface of the power conversion unit (2); a wiring terminal (6) is arranged on the side surface of the direct current bus unit on the upper surface of the power conversion unit (2); the connecting terminal (6) is connected to the rectifying unit (1), the rectifying unit (1) is connected to the direct current bus unit, the power conversion unit (2) is also connected to the direct current bus unit, and the alternating current end of the power conversion unit (2) is connected with the connecting terminal (6).

2. A frequency converter circuit arrangement according to claim 1, characterized in that the dc bus unit comprises a first dc bus unit (3) and a second dc bus unit (4); the first direct current bus unit (3) is located on the lower surface of the power conversion unit (2), and the second direct current bus unit (4) is located on the upper surface of the power conversion unit (2).

3. A frequency converter circuit arrangement according to claim 1, characterized in that the first dc bus-bar unit (3) and the second dc bus-bar unit (4) are formed by electrolytic capacitors connected in series and parallel.

4. A frequency converter circuit arrangement according to claim 3, characterized in that the + and-poles of the capacitance of the first DC bus-bar unit (3) are directly soldered to the DC + and DC-pins of the power conversion unit (2); the capacitor of the second direct current bus unit (4) is positioned in the heat dissipation unit space, and the capacity of the capacitor is 3/4 of the whole capacity.

5. The circuit layout structure of claim 1, wherein the power conversion unit is attached to the heat dissipation unit.

6. The frequency converter circuit arrangement according to claim 1, wherein the heat sink unit comprises a heat sink (8) and a heat dissipation fan (7), and the heat dissipation fan (7) is disposed at a side of the heat sink (8).

7. The circuit layout structure of the frequency converter according to claim 6, wherein the rectifying unit (1), the power conversion unit (2), the dc bus unit, the control board (5), the connecting terminal (6) and the heat dissipation unit are all disposed in the housing of the frequency converter.

8. A frequency converter circuit arrangement according to claim 7, characterized in that the heat sink blower (7) is arranged on the frequency converter housing.

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