CN212367118U - Bus capacitor pre-charging circuit, frequency converter and air conditioning equipment - Google Patents

Abstract

The utility model discloses a generating line electric capacity is charging circuit, converter and air conditioning equipment in advance. Wherein, this circuit includes: the input end of the charging module is connected with an alternating current power supply, and the output end of the charging module is connected with the direct current bus and used for outputting variable current; and the input end of the controller is connected with the direct current bus, and the output end of the controller is connected with the charging module and used for adjusting the current output by the charging module according to the voltage of the direct current bus. Through the utility model discloses, can realize nimble charging current of adjusting, avoid because the power-on direct current voltage is whole to be added at cement resistance both ends in the twinkling of an eye, lead to the condition that cement resistance current is too big to burn out, promote the security.

Description

Bus capacitor pre-charging circuit, frequency converter and air conditioning equipment

Technical Field

The utility model relates to an electron electric power technical field particularly, relates to a bus-bar capacitor is charging circuit, converter and air conditioning equipment in advance.

Background

The traditional air conditioner pre-charging circuit is formed by connecting a relay and a cement resistor in a main loop in parallel. When the frequency converter is powered on, the relay is disconnected, the three-phase alternating current input is rectified by the rectifying module and then charges the capacitor through the cement resistor, and when the bus voltage reaches a set value, the relay is controlled to be closed, so that the cement resistor is short-circuited, and the pre-charging of the capacitor is completed. The mode has the advantages of low charging efficiency and complex operation, and more importantly, the current is high at the moment of starting charging, so that the cement resistor can be damaged, and the safe operation of the frequency converter is influenced.

Aiming at the problems that the charging instantaneous current is large and the charging resistor is impacted in the prior art, an effective solution is not provided at present.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an in provide a bus capacitor is charging circuit, converter and air conditioning equipment in advance to it is great to fill the electric current in the twinkling of an eye to charge among the solution prior art, produces the problem of impact to the circuit.

In order to solve the technical problem, the utility model provides a bus capacitor is charging circuit in advance, bus capacitor's quantity is two at least, inserts between the direct current generating line after the series connection, and wherein, a voltage-sharing resistance that connects in parallel at every bus capacitor both ends, this circuit includes:

the input end of the charging module is connected with an alternating current power supply, and the output end of the charging module is connected with the direct current bus and used for outputting variable current;

and the input end of the controller is connected with the direct current bus, and the output end of the controller is connected with the charging module and used for adjusting the current output by the charging module according to the voltage of the direct current bus.

Further, the charging module comprises three charging units arranged in parallel: first charging unit, second charging unit and third charging unit, first charging unit the second charging unit and the third charging unit connects gradually respectively alternating current power supply's first phase line, second phase line and third phase line.

Further, in the first charging unit, the second charging unit and the third charging unit, each charging unit includes a thyristor and a diode connected in series in the same direction, and the first phase line of the ac power supply is connected between the thyristor and the diode in the first charging unit; a second phase line of the alternating current power supply is connected between a thyristor and a diode in the second charging unit; and a third phase line of the alternating current power supply is respectively connected between a thyristor and a diode in the third charging unit.

Further, the controller is specifically configured to control the firing angle of the thyristor to decrease, so that the output current of the charging module increases; or controlling the trigger angle of the thyristor to be unchanged, so that the output current of the charging module is unchanged;

wherein the difference of the firing angles between any two thyristors is always kept at 120 degrees, and the maximum variation value of the firing angle of each thyristor is 180 degrees.

Further, each charging unit further includes:

and the current limiting resistor is connected with the thyristor and the diode in series.

Further, each charging unit further includes:

and the indicating element is connected with the thyristor and the diode in series and is used for indicating whether the charging unit works normally or not.

Further, the circuit further comprises:

the input end of the current detection unit is connected between the charging module and the direct current bus, and the output end of the current detection unit is connected with the controller, is used for detecting the current output by the charging module and transmits the current to the controller;

the controller is further configured to control the charging module to be turned on or off according to the magnitude of the current output by the charging module.

The utility model also provides a converter, including above-mentioned bus-bar capacitance pre-charge circuit.

The utility model also provides an air conditioning equipment, including above-mentioned converter.

Use the technical scheme of the utility model, through the electric current that the module output that charges changes to through the controller according to DC bus voltage, adjust the electric current of the module output that charges can realize adjusting charging current in a flexible way, avoids because the power-on direct current voltage is whole to be added at cement resistance both ends in the twinkling of an eye, leads to the too big condition of burning out of cement resistance current, promotes the security.

Drawings

Fig. 1 is a structural diagram of a bus capacitor precharge circuit according to a first embodiment of the present invention;

fig. 2 is a structural diagram of a bus capacitor precharge circuit according to a second embodiment of the present invention;

fig. 3 is a structural diagram of a bus capacitor precharge circuit according to a third embodiment of the present invention;

fig. 4 is a structural diagram of a bus capacitor precharge circuit according to a fourth embodiment of the present invention;

fig. 5 is a structural diagram of a bus capacitor precharge circuit according to a fifth embodiment of the present invention;

fig. 6 is a diagram illustrating a connection relationship between a bus capacitor precharge circuit and a load circuit according to a sixth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the embodiments of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that although the terms first, second, third, etc. may be used to describe the charging units in the embodiments of the present invention, the charging units should not be limited to these terms. These terms are only used to distinguish between charging units disposed at different locations. For example, the first charging unit may also be referred to as a second charging unit, and similarly, the second charging unit may also be referred to as a first charging unit without departing from the scope of embodiments of the present invention.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.

The following describes in detail alternative embodiments of the present invention with reference to the accompanying drawings.

Example 1

This embodiment provides a bus capacitor precharge circuit, bus capacitor's quantity is two at least, in this embodiment, including first bus capacitor C1 and second bus capacitor C2 between the direct current generating line, first bus capacitor C1 and second bus capacitor C2 insert between the first line and the second line of direct current generating line after establishing ties, first bus capacitor C1 even the section is parallelly connected and is set up first equalizer resistor R1, the parallelly connected second equalizer resistor R2 that sets up in both ends of second bus capacitor C2, in order to realize charging above-mentioned first bus capacitor C1 and second bus capacitor C2, fig. 1 is according to the utility model discloses bus capacitor precharge circuit's structure diagram of first embodiment, as shown in fig. 1, this circuit includes:

the charging module 10, the input end of the charging module 10 is connected with the alternating current power supply AC, the output end includes a first terminal and a second terminal, the first terminal and the second terminal are respectively connected with a first line and a second line of the direct current bus, and are used for outputting a variable current;

the charging device further comprises a controller 20, wherein the input end of the controller 20 is connected with the first line and the second line of the direct current bus, and the output end of the controller 20 is connected with the charging module 10 and used for adjusting the current output by the charging module 10 according to the voltage between the first line and the second line of the direct current bus.

The bus capacitor pre-charging circuit of this embodiment is through the current that the module output that charges changes to through the controller according to direct current bus voltage, adjust the current of the module output that charges can realize nimble regulation charging current, avoid because the power-on direct current voltage all adds at cement resistance both ends in the twinkling of an eye, lead to the too big condition of burning out of cement resistance current, promote the security.

Example 2

This embodiment provides another kind of bus capacitor precharge circuit, and fig. 2 is according to the utility model discloses bus capacitor precharge circuit's of second embodiment structure chart, in order to realize charging to direct current bus capacitor when realizing three-phase alternating current rectification, as shown in fig. 2, the module of charging includes the three charging unit of parallelly connected setting: the first charging unit 101, the second charging unit 102 and the third charging unit 103 are respectively connected with the first phase line, the second phase line and the third phase line of the alternating current power supply in sequence, the three-phase alternating current rectification is realized through the first charging unit 101, the second charging unit 102 and the third charging unit 103, the current with variable size is output, and the bus capacitor is charged through the variable current.

Example 3

This embodiment provides another bus capacitor pre-charging circuit, fig. 3 is a structural diagram of a bus capacitor pre-charging circuit according to a third embodiment of the present invention, as shown in fig. 3, in the first charging unit 101, the second charging unit 102 and the third charging unit 103, each charging unit includes a thyristor and a diode connected in series in the same direction, the first phase line of the AC power source AC is connected between the thyristor T1 and the diode D1 in the first charging unit 101; a second phase line of the alternating current power AC is connected between the thyristor T2 and the diode D2 in the second charging unit 102; the third phase line of the alternating current power AC is connected between the thyristor T3 and the diode D3 in the third charging unit 103. The output end of the controller 20 is respectively connected to the control end of the thyristor T1, the control end of the thyristor T2 and the control end of the thyristor T3 in sequence, and the controller 20 controls the trigger angles of the thyristors T1, T2 and T3 to decrease, so that the output current of the charging module 10 increases; alternatively, the output current of the charging module 10 is made constant by controlling the firing angles of the thyristors T1, T2, and T3 to be constant, thereby realizing the adjustment of the charging current. In the present embodiment, the difference of the firing angles between any two thyristors is always maintained at 120 °, the maximum variation value of the firing angle of each thyristor is 180 °, for example, the initial angles of the thyristors T1, T2 and T3 may be 180 °, -60 ° and 60 °, the final angles may be 0 °, 120 °, -120 °, the firing angles of the thyristors T1, T2 and T3 may be varied at the maximum by 180 °, and the output current is changed from the minimum value to the maximum value during the process of the change of the firing angles from the initial angles to the final angles.

Example 4

This embodiment provides another kind of bus capacitor pre-charging circuit, fig. 4 is a structure diagram of the bus capacitor pre-charging circuit according to the fourth embodiment of the present invention, because the thyristor has the maximum working current, in order to limit the current flowing through each thyristor, as shown in fig. 4, the first charging unit 101, the second charging unit 102 and the third charging unit 103 respectively include the first current limiting resistor R3, the second current limiting resistor R4 and the third current limiting resistor R5, wherein the first current limiting resistor R3 is connected in series with the thyristor T1 and the diode D1, the second current limiting resistor R4 is connected in series with the thyristor T2 and the diode D2, the third current limiting resistor R5 is connected in series with the thyristor T3 and the diode D3, and through the current limiting resistors, the current flowing through each thyristor is limited, and the safe operation of the thyristor is ensured.

In addition, each charging unit may be failed and turned off, and in order to enable a user to intuitively know whether each charging unit is working normally and quickly locate the failure, the first charging unit 101, the second charging unit 102, and the third charging unit 103 respectively include: the first indication element D4, the second indication element D5 and the third indication element D6 are connected in series, wherein the first indication element D4 is connected in series with the thyristor T1 and the diode D1 to indicate whether the first charging unit 101 operates normally, the second indication element D5 is connected in series with the thyristor T2 and the diode D2 to indicate whether the second charging unit 102 operates normally, and the second indication element D6 is connected in series with the thyristor T3 and the diode D3 to indicate whether the third charging unit 103 operates normally, specifically, the first indication element D4, the second indication element D5 and the third indication element D6 are turned on and off simultaneously, and if one on and two off or one on and one off occurs, the circuit is determined to be in an abnormal state, so that the circuit can be powered off manually in time, and a safety accident can be avoided. The first indicator element D4, the second indicator element D5, and the third indicator element D6 may be light emitting diodes.

Example 5

This embodiment provides another kind of bus capacitor pre-charge circuit, and fig. 5 is according to the utility model discloses bus capacitor pre-charge circuit's of fifth embodiment structure chart, in order to avoid charging current too big, leads to the security problem, as shown in fig. 5, this circuit still includes:

the input end of the current detection unit 30 is connected between the charging module 10 and the first line of the direct current bus, and the output end of the current detection unit 30 is connected with the controller 20, and is used for detecting the current output by the charging module and transmitting the current to the controller 20; the controller 20 controls the charging units in the charging module to be turned on or off according to the magnitude of the current output by the charging module, and further controls the whole charging module to be turned on or off, specifically, when the output current of the charging module is greater than a preset current threshold, each charging unit is controlled to be turned off to cut off the charging module, and circuit protection is realized when the charging current is too large.

Example 6

This embodiment provides another kind of bus capacitor pre-charge circuit, fig. 6 is a connection diagram of the bus capacitor pre-charge circuit and the load circuit according to the sixth embodiment of the present invention, as shown in fig. 6, this circuit includes: thyristors T1-T3, diodes D1-D3, thyristors T1-T3 and diodes D1-D3 jointly form a semi-controlled rectifying circuit in the three-phase pre-charging circuit, the trigger angle of the thyristors is controlled to gradually decrease from 180 degrees, when the trigger angle reaches 0 degree, the output current of the charging circuit reaches the maximum, and in the process of gradually decreasing the trigger angle of the thyristors, the thyristors T1-T3 are simultaneously conducted to charge the capacitors. C1 and C2 are charging capacitors, two ends of C1 and C2 and a load circuit formed by a resistor R and a switch Q form a closed loop, and D4 to D6 are light emitting diodes and used for indicating the working states of thyristors T1 to T3.

The working principle of the bus capacitor and the charging circuit of the embodiment is as follows:

by adopting the semi-controlled rectifying circuit, a cement resistor and a relay in a traditional circuit are replaced, and the semi-controlled rectifying circuit is used as a switch for controlling the charging circuit. After the frequency converter is electrified, under the condition of normal charging, the trigger angles of the three thyristors are controlled to be gradually reduced, wherein the thyristor T1 is decreased from 180 degrees to 0 degrees, the initial trigger angles of the thyristors T2, T3 and T1 are different, the difference value of the trigger angles of the three thyristors is kept at 120 degrees, when the trigger angle of the thyristor T1 is changed from 180 degrees to 0 degrees, the three thyristors are conducted and the trigger angles are gradually changed, so that the output current is gradually increased, the pre-charging of the bus capacitor is realized, the output voltage is uniformly increased along with the reduction of the trigger angle of the thyristor, the current is also increased along with the increase of the trigger angle, the control of the trigger angle can be flexibly adjusted, the main circuit is ensured not to generate overlarge charging current, the problem that the traditional pre-charging circuit is burnt due to the fact that the direct current voltage is completely applied to two ends of the cement resistor at the, when the trigger angle of the thyristor T1 reaches 0 degree, the trigger angles of the three thyristors reach the minimum and the output current reaches the maximum at the same time, in the process of changing the trigger angle, whether the pre-charging of the bus capacitor is finished or not is detected in real time, if the pre-charging of the bus capacitor is finished, the trigger angle is controlled not to change any more, if the pre-charging of the bus capacitor is not finished, the trigger angle is controlled to continuously reduce until the pre-charging is reduced to the minimum, after the output current is the maximum, if the charging is not finished, the charging is kept by taking the maximum output current as the bus current.

In order to meet the working condition of the driving plate, a bus voltage threshold value is set, whether the circuit meets the working condition is judged by judging whether the voltage reaches the voltage threshold value, when the bus voltage does not reach the voltage threshold value, the trigger angle of the thyristor is continuously reduced until the bus voltage reaches the voltage threshold value, and if the trigger angle is reduced by 180 degrees, the bus voltage does not reach the voltage threshold value, and the trigger angle of the thyristor is controlled not to change.

The precharge circuit of the present embodiment further includes: and the current sampling unit is used for sampling the current value in the charging process, comparing the sampling result with a preset protection current threshold value, immediately disconnecting the thyristor to protect the rear-end circuit when the sampling current is greater than the preset protection current threshold value, and continuously keeping the thyristor on if the sampling current is less than or equal to the preset protection current value.

In practice, when a frequency converter works abnormally, when a circuit passes through a large current, heating components such as cement resistors and the like are easily damaged, and even the circuit can explode a plate when the circuit is serious, potential safety hazards exist, and factors causing the circuit to generate the large current are roughly two, namely, a rear end circuit has short circuit of the components, so that the circuit generates the large current in a straight-through mode; and the other is that the switch element is damaged and the switch cannot be normally controlled to be closed. Therefore, the front end of each branch of the semi-controlled rectifying circuit is provided with the light emitting diode, whether the thyristor normally works is judged according to the on-off condition of the light emitting diode, when the thyristor normally works, the three diodes should have the same on-off phenomenon, if the on-off or the on-off condition appears in a staggered mode, the circuit is judged to be in an abnormal state, if the circuit is found to be in the abnormal state, the circuit is timely powered off manually, and safety accidents are avoided.

The bus capacitor pre-charging circuit of the embodiment adopts the semi-controlled rectifying device, so that cement resistors and relays used in the traditional circuit are saved, the hardware structure is simplified, the problems that the charging time is adjusted by replacing RC resistors in the traditional circuit and the operation is complex are solved, the charging time can be flexibly changed, and the problem that the charging efficiency of the traditional pre-charging circuit is low is solved; the control of the charging current is realized by controlling the change speed of the trigger angle through software, so that the problem that components are burnt out due to large charging current caused by the fact that direct current voltage is completely applied to two ends of a cement resistor at the moment of electrifying in the traditional pre-charging circuit is solved; the on-off of the thyristor is controlled by comparing the sampling current with the set current, so that the phenomenon that the cement resistor is damaged due to overlarge current impact at the moment of electrifying to influence the safe operation of the frequency converter is avoided; whether the thyristor is damaged or not is indicated through the light emitting diode, and faults can be found in time.

Example 7

The embodiment provides a frequency converter, including the bus capacitor pre-charging circuit in the above-mentioned embodiment for realize accomplishing the charging to the bus capacitor through the change electric current, avoid appearing instantaneous heavy current, promote the security of frequency converter.

Example 8

The embodiment provides an air conditioning equipment, including the converter in the above-mentioned embodiment for realize accomplishing the charging to the bus capacitance through the change electric current, avoid appearing instantaneous heavy current, promote whole air conditioning equipment's security.

The above-described circuit embodiments are only illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims (9)

1. The utility model provides a bus capacitor is charging circuit in advance, bus capacitor's quantity is two at least, inserts between the direct current bus after establishing ties, wherein, a equalizer resistor is connected in parallel at every bus capacitor both ends, its characterized in that, the circuit includes:

the input end of the charging module is connected with an alternating current power supply, and the output end of the charging module is connected with the direct current bus and used for outputting variable current;

and the input end of the controller is connected with the direct current bus, and the output end of the controller is connected with the charging module and used for adjusting the current output by the charging module according to the voltage of the direct current bus.

2. The circuit of claim 1, wherein the charging module comprises three charging units arranged in parallel: first charging unit, second charging unit and third charging unit, first charging unit the second charging unit and the third charging unit connects gradually respectively alternating current power supply's first phase line, second phase line and third phase line.

3. The circuit of claim 2, wherein each of the first charging unit, the second charging unit, and the third charging unit comprises a thyristor and a diode connected in series in the same direction, and the first phase line of the ac power source is connected between the thyristor and the diode in the first charging unit; a second phase line of the alternating current power supply is connected between a thyristor and a diode in the second charging unit; and a third phase line of the alternating current power supply is respectively connected between a thyristor and a diode in the third charging unit.

4. The circuit of claim 3,

the controller is specifically configured to control a firing angle of the thyristor to decrease, so that an output current of the charging module increases; or controlling the trigger angle of the thyristor to be unchanged, so that the output current of the charging module is unchanged;

wherein the difference of the firing angles between any two thyristors is always kept at 120 degrees, and the maximum variation value of the firing angle of each thyristor is 180 degrees.

5. The circuit of claim 3, wherein each charging unit further comprises:

and the current limiting resistor is connected with the thyristor and the diode in series.

6. The circuit of claim 3, wherein each charging unit further comprises:

and the indicating element is connected with the thyristor and the diode in series and is used for indicating whether the charging unit works normally or not.

7. The circuit of claim 1, further comprising:

the input end of the current detection unit is connected between the charging module and the direct current bus, and the output end of the current detection unit is connected with the controller, is used for detecting the current output by the charging module and transmits the current to the controller;

the controller is further configured to control the charging module to be turned on or off according to the magnitude of the current output by the charging module.

8. A frequency converter, characterized in that it comprises a bus capacitor pre-charging circuit according to any of claims 1-7.

9. An air conditioning apparatus characterized by comprising the inverter of claim 8.

Images