CN203289169U - Pre-charging device of power unit cascaded high-voltage inverter - Google Patents

Pre-charging device of power unit cascaded high-voltage inverter Download PDF

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Publication number
CN203289169U
CN203289169U CN2013203450843U CN201320345084U CN203289169U CN 203289169 U CN203289169 U CN 203289169U CN 2013203450843 U CN2013203450843 U CN 2013203450843U CN 201320345084 U CN201320345084 U CN 201320345084U CN 203289169 U CN203289169 U CN 203289169U
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CN
China
Prior art keywords
phase
voltage
charging
bidirectional switch
transformer
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CN2013203450843U
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Chinese (zh)
Inventor
李永盼
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上海亿思特电气股份有限公司
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Abstract

The utility model discloses a pre-charging device of a power unit cascaded high-voltage inverter. The pre-charging device mainly comprises a three-phase bidirectional switch (44), a three-phase electric reactor (45) and an on-off control circuit (46). The three-phase bidirectional switch (44) and the three-phase electric reactor (45) are connected in series. One end of the three-phase bidirectional switch (44) is connected with a three-phase alternating current. The other end of the three-phase electric reactor (45) is connected with a three-phase auxiliary winding of a transformer of the high-voltage inverter. The on-off control circuit (46) is connected with the three-phase bidirectional switch (44) to provide a control signal to the three-phase bidirectional switch (44). With the adoption of the pre-charging device, interference of a three-phase low-voltage commercial power grid is lowered, and impacts on a three-phase high-voltage power grid when a high voltage is applied to the high-voltage inverter are inhibited.

Description

The pre-charging device of power unit cascade type high voltage frequency converter

Technical field

The utility model relates to power electronic technology, relate in particular to a kind of pre-charging device of power unit cascade type high voltage frequency converter, be used for realizing the stepless precharge of high voltage converter, the interference of reduction to the three-phase low-voltage utility grid, when the high pressure that suppresses high voltage converter powers on to the impact of three-phase high-voltage electrical network, the activation that can also realize the power cell dc filter capacitor enables, thereby extends the high voltage converter working life.

Background technology

In the high voltage converter field, from Peter W. Hammond since nineteen ninety-five proposes the unit series high-voltage frequency converter, this method that realizes the high-tension electricity conversion by the low-voltage power converter technique because its output voltage wave mode is good, input harmonic current is low, cost is low, easy to maintenance, become the mainstream technology of high voltage converter, domestic and international many producers have all released the product based on this technology., owing to saving energy and reduce the cost, improving production technology and improving the aspect effects such as service life of structure remarkable, apply more prevalent.

Figure 1A is described is exactly the typical scenario of existing this class high voltage converter, and it is every is formed by 3 power unit cascades.As shown in Figure 1A, this high voltage converter comprises: transformer 1, nine identical power cells (as 2AU), controller 3 and high-voltage frequency converter pre-charging circuit 4.Wherein the structure of each power cell is identical, and its structure as shown in Figure 1B; Transformer 1 comprises three-phase secondary winding (as 12AU) and auxiliary three-phase secondary winding 12X that 11,9 phase places of 1 former limit winding are different.

Can find out from Figure 1B, the DC filtering circuit 23 of each power cell comprises filter capacitor 231,232, for the voltage stabilization of holding power unit dc bus, filter capacitor 231,232 capacity very large (generally more than thousands of microfarads), be generally electrochemical capacitor.When high voltage converter is connected the high pressure three phase mains, need to the filter capacitor of each power cell be charged, can produce excessive pulse current, not only easily cause rectification circuit 22 damages of power cell and burning of fuse 21, and reduce the working life of filter capacitor; High voltage converter also needs to draw very large impulse current from high-voltage fence, and high-voltage fence is formed and impacts, and easily affects the work of other load on high-voltage fence, even causes high-voltage fence tripping operation outage.

Generation for fear of above-mentioned phenomenon, present common practice is before high pressure powers on, adopt three-phase low-voltage electric main (as 380V) by the auxiliary secondary winding 12X of the three-phase of transformer 1, power cell to be charged, as shown in Figure 2, at first contactor 41 closures, three-phase low-voltage electric main (as 380V) is connected the auxiliary winding 12X(of three-phase of transformer 1 with reference to Figure 1A by current-limiting resistance 43), each power cell is carried out precharge; Through after a while, treat that the DC bus-bar voltage of power cell is substantially saturated, more closed contactor 42, the three-phase low-voltage civil power is directly connected the auxiliary secondary winding 12X of Three-Phase Transformer, and power cell is directly charged; Disconnect finally contactor 42,41, namely can carry out high pressure and power on.

Power unit cascade type high voltage frequency converter adopts above-mentioned precharge mode, and logic is simple, and it is convenient to realize, thereby obtains extensive use, but there is its weak point in this precharge mode.

At first, precharge realizes by contactor 42 bypass current-limiting resistances 43, for level is arranged, switches, and when contactor 42,41 is closed successively, still can draw impulse current from the three-phase low-voltage utility grid, easily the work of high voltage converter control circuit 3 is formed interference.

Secondly, because the three-phase of high voltage converter assists the rated voltage of winding identical with the three-phase low-voltage civil power, the filter capacitor voltage of power cell can't reach its rated value, thereby when high pressure powers on, still from high-voltage fence, draw impulse current, still may affect the normal operation of miscellaneous equipment on high-voltage fence.

The 3rd, when high voltage converter at the scene during long-term off-duty, the performance of filter capacitor in power cell (being generally electrochemical capacitor) is easily degenerated, again the activation of must charging before puts into operation, namely apply rated voltage and continue for some time, and adopting existing pre-charge method can't realize above-mentioned activation.

The utility model content

In view of this, main purpose of the present utility model is to provide a kind of pre-charging device of power unit cascade type high voltage frequency converter, to realize the stepless precharge of high voltage converter, the interference of reduction to the three-phase low-voltage utility grid, when the high pressure that suppresses high voltage converter powers on to the impact of three-phase high-voltage electrical network, the activation that can also realize the filter capacitor (as electrochemical capacitor) in power cell enables, thereby extends the working life of high voltage converter.

For achieving the above object, the technical solution of the utility model is achieved in that

A kind of pre-charging device of power unit cascade type high voltage frequency converter, described pre-charging device mainly comprise three-phase bidirectional switch 44, three-phase reactor 45 and ON-OFF control circuit 46; Wherein:

Described three-phase bidirectional switch 44 is connected in series with three-phase reactor 45; One end of described three-phase bidirectional switch 44 connects three-phase alternating current; The other end of described three-phase reactor 45 connects the auxiliary winding of three-phase of transformer in high voltage converter;

Described ON-OFF control circuit 46 is connected with described three-phase bidirectional switch 44, for described three-phase bidirectional switch 44 provides control signal.

Wherein: the described three-phase bidirectional switch 44 latter linked three-phase alternating current of connecting with three-phase reactor 45 is the three-phase low-voltage civil power.

ON-OFF control circuit 46 is connected to obtain required electric power with described three-phase low-voltage civil power.

In described high voltage converter, the operating voltage of the auxiliary winding of Three-Phase Transformer is lower than the voltage of three-phase low-voltage civil power.

A kind of pre-charging device of power unit cascade type high voltage frequency converter, this pre-charging device mainly comprise three-phase bidirectional switch 44, three-phase reactor 45, ON-OFF control circuit 46 and three-phase transformer 47; Wherein:

Described three-phase reactor 45, three-phase bidirectional switch 44 and three-phase transformer 47 are connected in series successively; The output that the armature winding of described three-phase transformer 47 connects three-phase alternating current, secondary winding is connected with described three-phase bidirectional switch 44;

The other end of described three-phase reactor 45 is connected with the auxiliary winding of three-phase of transformer in high voltage converter;

Described ON-OFF control circuit 46 is connected with described three-phase bidirectional switch 44, for described three-phase bidirectional switch 44 provides control signal.

Wherein: the three-phase alternating current that described three-phase transformer 47 armature windings connect is the three-phase low-voltage civil power.

ON-OFF control circuit 46 connects described three-phase low-voltage civil power to obtain required electric power.

Described three-phase transformer 47 is step-up transformer, and the voltage of its secondary winding is higher than the voltage of its former limit winding.

In described high voltage converter, the rated operational voltage of the auxiliary winding of the three-phase of transformer is identical with described three-phase low-voltage civil power.

A kind of pre-charging device of claim 1 or 5 described power unit cascade type high voltage frequency converter, described three-phase bidirectional switch 44 is the solid-state power switch of two-way admittance.

The pre-charging device of power unit cascade type high voltage frequency converter provided by the utility model has the following advantages:

At first, the pre-charge process of high voltage converter is controlled by the three-phase bidirectional switch, then through three-phase reactor current limliting, filtering, the power cell charging voltage can be regulated continuously, the impulse current of drawing from the three-phase low-voltage utility grid is limited.

Secondly, the applying voltage and can exceed the three-phase low-voltage line voltage of the auxiliary winding of three-phase, only when exceeding its normal working voltage, just drops into the filter capacitor voltage of power cell high-tension electricity, each power cell can not produce the input impulse current, thereby the fashionable rush of current to high-voltage fence of high voltage converter high-pressure flushing significantly reduces.

The 3rd, the filter capacitor voltage of power cell even can reach its rated value, so, after high voltage converter leaves unused at the scene for a long time, can carry out performance recovery to the filter capacitor in power cell (especially electrochemical capacitor) by the high voltage converter pre-charging functions, thereby extend the useful life of high voltage converter.

Description of drawings

Figure 1A is the principle schematic of existing power unit cascade type high voltage frequency converter;

Figure 1B is the principle schematic of Figure 1A medium-high voltage frequency converter power cell;

Fig. 2 is the principle schematic of existing high-voltage frequency converter pre-charging circuit;

Fig. 3 is the principle schematic of a kind of high voltage converter pre-charging device of the present utility model;

Fig. 4 is the principle schematic of another kind of high voltage converter pre-charging device of the present utility model;

Fig. 5 is another embodiment of high voltage converter pre-charging device of the present utility model.

[critical piece symbol description]

1: transformer

11: former limit winding;

12AU, 12AV, 12AW, 12BU, 12BV, 12BW, 12CU, 12CV, 12CW: secondary winding;

12X: three-phase is assisted winding (u, v, w are respectively its three-phase terminal);

2,2AU, 2AV, 2AW; 2BU, 2BV, 2BW; 2CU, 2CV, 2CW: power cell;

21: fuse;

22: rectification circuit;

23: the DC filtering circuit;

231,231: filter capacitor;

233,234: grading resistor;

24: inverter circuit;

25: the power cell control circuit;

3, master controller;

4: pre-charging device;

41,42: contactor;

43: current-limiting resistance;

44: the three-phase bidirectional switch;

45: three-phase reactor;

46: ON-OFF control circuit;

47: three-phase transformer;

471: armature winding;

472: secondary winding;

5: high-voltage motor;

6: the three-phase high-voltage electrical network;

7: three-phase low-voltage civil power (R, S, T are respectively its three-phase terminal).

Embodiment

Below in conjunction with accompanying drawing and embodiment of the present utility model, the pre-charging device of power unit cascade type high voltage frequency converter is described further.

Pre-charging device as an example of Fig. 3~Fig. 5 example to power unit cascade type high voltage frequency converter of the present utility model describes.

Fig. 3 is the principle schematic of a kind of high voltage converter pre-charging device of the present utility model.As shown in Figure 3, described high voltage converter pre-charging device 4 comprises: three-phase bidirectional switch 44, three-phase reactor 45 and ON-OFF control circuit 46.Wherein, described three-phase bidirectional switch 44 is connected in series with three-phase reactor 45, lower end after series connection is that R, S, T end are the input of pre-charging device 4, connecting three-phase alternating current (is the three-phase low-voltage civil power in Fig. 3, upper end represents that the output of pre-charging device is u, v, w end, and the auxiliary winding 12X(of three-phase that connects transformer 1 in high voltage converter please refer to Figure 1A).

ON-OFF control circuit 46 is connected with three-phase bidirectional switch 44, for described three-phase bidirectional switch 44 provides control signal.Described three-phase bidirectional switch 44 comprises three bidirectional triode thyristors, and ON-OFF control circuit 46 need to provide No. 3 bidirectional triode thyristor gate pole triggering signals for three-phase bidirectional switch 44.

In Fig. 3, the input of described pre-charging device 4 directly connects three-phase low-voltage civil power R, S, T, and ON-OFF control circuit 46 also connects the three-phase low-voltage civil power, with the required electric power of the work of obtaining.

In conjunction with Figure 1A, Figure 1B, when adopting pre-charging device shown in Figure 3, in high voltage converter, the rated voltage of the auxiliary winding of the three-phase of transformer should be lower than the rated voltage of three-phase low-voltage civil power.For example, at home, the rated voltage of three-phase low-voltage civil power is 380V, considers 10% voltage fluctuation, and its minimum voltage can be lower than 342V; High-voltage fence is considered 5% voltage fluctuation, for the 10KV electrical network, its ceiling voltage can be higher than 10.5KV, if the highest net at high-voltage fence is depressed, the operating voltage of the auxiliary winding 12X of the three-phase of the transformer 1 of high voltage converter is still lower than the minimum voltage (as 342V) of three-phase low-voltage civil power, when adopting high voltage converter pre-charging device shown in Figure 3 to carry out precharge, the filter capacitor voltage (as 231) in each power cell (as 2AU) can reach it more than normal working voltage.After pre-charge process finishes, the voltage of power cell filter capacitor (as 231) is slow decreasing along with the discharge by its grading resistor in parallel (as 233), if at filter capacitor voltage, high voltage converter is dropped into high pressure in still higher than the time period of its normal working voltage, power cell itself can not cause impulse current, thereby the impulse current that high voltage converter is drawn from high-voltage fence can significantly reduce.

For high voltage converter pre-charging device 4 shown in Figure 3, its power up can be taked following steps: at first, drop into the three-phase low-voltage civil power, ON-OFF control circuit 46 in pre-charging device 4 is started working, three-phase bidirectional switch 44 is controlled, the angle of flow of three-phase bidirectional switch 44 is progressively increased, the output voltage of pre-charging device 4 increases thereupon gradually, by the auxiliary winding 12X of the three-phase of high voltage converter transformer 1 to the filter capacitor (as 231) in each power cell (as 2AU) of high voltage converter charge (please refer to Figure 1A); Through after a while, the voltage of the filter capacitor of each power cell (as 231) can be charged to it more than normal working voltage, at this moment ON-OFF control circuit 46 namely can be controlled 44 shutoffs of three-phase bidirectional switch, the filter capacitor voltage of power cell starts decay immediately, during this period of time, high voltage converter can drop into the high pressure three-phase alternating current before decaying to its normal working voltage.

In conjunction with Figure 1A; in the pre-charging device of high voltage converter shown in Figure 3; auxiliary winding 12X often also has other functions due to the three-phase of transformer 1; for example in the running of high voltage converter; in case outward for the outage of three-phase low-voltage civil power; can continue power supply to the control circuit of high voltage converter, blower fan etc. by the auxiliary winding 12X of three-phase, and these loads often require the rated output voltage of the auxiliary winding of three-phase of transformer consistent with the three-phase low-voltage civil power.For this situation, Fig. 4 provides another embodiment of the pre-charging device 4 of high voltage converter.

The pre-charging device 4 of high voltage converter shown in Figure 4 except comprising three-phase bidirectional switch 44, three-phase reactor 45 and ON-OFF control circuit 46, also comprises a three-phase transformer 47; Wherein the armature winding 471 of three-phase transformer 47 connects three-phase low-voltage civil power R, S, T, as the input of pre-charging device 4; The secondary winding 472 of three-phase transformer 47 connects the lower end after three-phase bidirectional switch 44 and three-phase reactor series connection, so that three-phase alternating-current supply to be provided.

In Fig. 4, three-phase transformer 47 is step-up transformer, and the rated voltage of its secondary winding 472 is higher than the rated voltage of its armature winding 471; ON-OFF control circuit 46 still connects three-phase low-voltage civil power R, S, T, from the three-phase low-voltage utility grid, to obtain needed electric power.

In conjunction with Figure 1A, Figure 1B, in the pre-charging device 4 of high voltage converter shown in Figure 4, the rated voltage identical with the rated voltage of three-phase low-voltage civil power (as 380V) of the auxiliary winding 12X of the three-phase of transformer 1.Like this, effect by step-up transformer 47, can make the auxiliary winding 12X of three-phase of transformer 1 obtain regulating continuously and the filter capacitor of each power cell (as 2AU) (as 231) voltage can be charged to it more than normal working voltage, the input impulse current of each power cell (as 2AU) when thereby the elimination high pressure powers on, and the unlikely normal power supply function that affects the auxiliary winding 12X of three-phase.

In the pre-charging device 4 of the high voltage converter that the utility model provides, three-phase bidirectional switch 44 is solid-state power switch, and can two-way admittance.In Fig. 3 and Fig. 4, the three-phase bidirectional switch comprises respectively 3 bidirectional triode thyristors, can certainly adopt the solid-state power switch of other form.Corresponding with Fig. 3, Fig. 5 provides and has adopted the embodiment of controllable silicon as solid-state power switch, easily finds out, three-phase bidirectional switch 44 comprises 6 controllable silicons, and negative electrode, anode reverse parallel connection are to realize two-way admittance in twos.

The above, be only preferred embodiment of the present utility model, not is used for limiting protection range of the present utility model.

Claims (10)

1. the pre-charging device of a power unit cascade type high voltage frequency converter, is characterized in that, described pre-charging device mainly comprises three-phase bidirectional switch (44), three-phase reactor (45) and ON-OFF control circuit (46); Wherein:
Described three-phase bidirectional switch (44) is connected in series with three-phase reactor (45); One end of described three-phase bidirectional switch (44) connects three-phase alternating current; The other end of described three-phase reactor (45) connects the auxiliary winding of three-phase of transformer in high voltage converter;
Described ON-OFF control circuit (46) is connected with described three-phase bidirectional switch (44), for described three-phase bidirectional switch (44) provides control signal.
2. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 1, is characterized in that, described three-phase bidirectional switch (44) the latter linked three-phase alternating current of connecting with three-phase reactor (45) is the three-phase low-voltage civil power.
3. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 1 and 2, is characterized in that, ON-OFF control circuit (46) is connected to obtain required electric power with described three-phase low-voltage civil power.
4. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 1 and 2, is characterized in that, in described high voltage converter, the operating voltage of the auxiliary winding of Three-Phase Transformer is lower than the voltage of three-phase low-voltage civil power.
5. the pre-charging device of a power unit cascade type high voltage frequency converter, is characterized in that, this pre-charging device mainly comprises three-phase bidirectional switch (44), three-phase reactor (45), ON-OFF control circuit (46) and three-phase transformer (47); Wherein:
Described three-phase reactor (45), three-phase bidirectional switch (44) and three-phase transformer (47) are connected in series successively; The output that the armature winding of described three-phase transformer (47) connects three-phase alternating current, secondary winding is connected with described three-phase bidirectional switch (44);
The other end of described three-phase reactor (45) is connected with the auxiliary winding of three-phase of transformer in high voltage converter;
Described ON-OFF control circuit (46) is connected with described three-phase bidirectional switch (44), for described three-phase bidirectional switch (44) provides control signal.
6. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 5, is characterized in that, the three-phase alternating current that described three-phase transformer (47) armature winding connects is the three-phase low-voltage civil power.
7. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 6, is characterized in that, ON-OFF control circuit (46) connects described three-phase low-voltage civil power to obtain required electric power.
8. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 5, is characterized in that, described three-phase transformer (47) is step-up transformer, and the voltage of its secondary winding is higher than the voltage of its former limit winding.
9. the pre-charging device of power unit cascade type high voltage frequency converter according to claim 6, is characterized in that, in described high voltage converter, the rated operational voltage of the auxiliary winding of the three-phase of transformer is identical with described three-phase low-voltage civil power.
10. the pre-charging device of claim 1 or 5 a described power unit cascade type high voltage frequency converter, is characterized in that, described three-phase bidirectional switch (44) is the solid-state power switch of two-way admittance.
CN2013203450843U 2013-06-17 2013-06-17 Pre-charging device of power unit cascaded high-voltage inverter CN203289169U (en)

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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104038032A (en) * 2014-05-26 2014-09-10 株洲变流技术国家工程研究中心有限公司 Low-voltage precharging system for high-voltage variable frequency system, and control method of low-voltage precharging system
CN104659837A (en) * 2013-11-18 2015-05-27 天津施德科技有限公司 Frequency converter activation experimental instrument

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104659837A (en) * 2013-11-18 2015-05-27 天津施德科技有限公司 Frequency converter activation experimental instrument
CN104038032A (en) * 2014-05-26 2014-09-10 株洲变流技术国家工程研究中心有限公司 Low-voltage precharging system for high-voltage variable frequency system, and control method of low-voltage precharging system
CN104038032B (en) * 2014-05-26 2018-01-05 株洲变流技术国家工程研究中心有限公司 Low pressure pre-charge system and its control method for high voltage frequency conversion system

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20131113

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