阅读说明：本技术 能量回馈装置及其缓启动方法 (Energy feedback device and slow starting method thereof ) 是由 杜伟 戴永辉 陈志彬 白秋梁 肖卓名 郑金祥 于 2019-10-21 设计创作，主要内容包括：本发明涉及能量回馈技术领域,提供了能量回馈装置及其缓启动方法。该能量回馈装置包括断路器、交流接触器、滤波电路、功率模块、直流电容、直流接触器和可控整流电路；断路器一端电连接交流母线,另一端通过交流接触器和滤波电路电连接功率模块；直流电容并联在功率模块的直流侧；功率模块通过直流接触器与直流母线电连接；可控整流电路的交流端连接在断路器和交流接触器之间,直流端与直流电容并联。上述能量回馈装置通过可控整流电路按照一定的时序控制即可完成开机后直流电容和交流电容无冲击缓启动,能够很好的保护能量回馈装置中的部件,且可控整流电路的成本不高,使得整机成本较低。(The invention relates to the technical field of energy feedback, and provides an energy feedback device and a slow start method thereof, wherein the energy feedback device comprises a circuit breaker, an alternating current contactor, a filter circuit, a power module, a direct current capacitor, a direct current contactor and a controllable rectifying circuit, the end of the circuit breaker is electrically connected with an alternating current bus, the end of the circuit breaker is electrically connected with the power module through the alternating current contactor and the filter circuit, the direct current capacitor is connected in parallel to the direct current side of the power module, the power module is electrically connected with the direct current bus through the direct current contactor, the alternating current end of the controllable rectifying circuit is connected between the circuit breaker and the alternating current contactor, the direct current end of the controllable rectifying circuit is connected in parallel with the direct current capacitor, and the energy feedback device can complete the shock-free slow start of the direct current capacitor and the alternating current capacitor after starting through the controllable rectifying circuit according to timing control of , so that.)

The energy feedback device is characterized by comprising a circuit breaker, an alternating current contactor, a filter circuit, a power module, a direct current capacitor and a direct current contactor, wherein the end of the circuit breaker is used for being electrically connected with an alternating current bus, and the other end of the circuit breaker is electrically connected with the power module through the alternating current contactor and the filter circuit;

the energy feedback device further comprises a controllable rectifying circuit, the alternating current end of the controllable rectifying circuit is connected between the circuit breaker and the alternating current contactor, the direct current end of the controllable rectifying circuit is connected with the direct current capacitor in parallel, the controllable rectifying circuit is used for buffering the charging of the direct current capacitor through the alternating current bus after the circuit breaker is closed, and when the voltage of two ends of the direct current capacitor reaches the th threshold value, the alternating current capacitor in the filter circuit is subjected to inversion charging through the power module, so that the direct current capacitor and the alternating current capacitor are started slowly.

2. The energy feedback device as claimed in claim 1, wherein the controllable rectification circuit is a phase-controlled rectification circuit, and after phase locking, the phase-controlled rectification circuit increases the duty ratio of the pulse wave driving the switching tube from zero to complete conduction.

3. The energy feedback device as claimed in claim 2, wherein the controllable rectifier circuit is a three-phase bridge rectifier circuit, which comprises an ac terminal, a dc terminal and six thyristors, and two of the six thyristors are connected in series and then in parallel after groups are connected in series;

and the connecting point between the two thyristors in each group is connected with the alternating current end, and the other ends of the two thyristors in each group are connected with the direct current end.

4. The energy feedback device of any of wherein the energy feedback device further comprises a high voltage switch, and the circuit breaker is electrically connected to the ac bus via the high voltage switch.

5. The energy feedback device of claim 4 further comprising a transformer disposed between the high voltage switch and the circuit breaker.

6. The energy feedback device as claimed in any one of claims 1-3 and wherein the energy feedback device further comprises a fuse disposed between the dc capacitor and the dc contactor.

7. The energy feedback device as in any of wherein the filter circuit comprises an ac capacitor and an inductor, the inductor being disposed between the ac contactor and the power module, the ac capacitor being disposed between the ac contactor and the inductor.

8, method of energy feedback device's slow start, characterized by, includes:

closing the circuit breaker, and applying the alternating-current bus voltage to the alternating-current end of the controllable rectifying circuit;

starting the controllable rectifying circuit to perform phase control rectification on the voltage at the alternating current end and then charging the direct current capacitor through the direct current end;

when the voltage of two ends of the direct current capacitor reaches the th threshold value, the alternating current capacitor is charged through the power module;

when the voltage at two ends of the alternating current capacitor and the voltage at the alternating current end of the controllable rectifying circuit meet the th preset condition, the controllable rectifying circuit is turned off, and the alternating current contactor is closed;

after the alternating current capacitor is started slowly, the direct current capacitor is charged and boosted through the power module, so that the voltage at two ends of the direct current capacitor and the voltage of a direct current bus meet a second preset condition, and the direct current contactor is closed.

9. The slow start method of an energy feedback device as claimed in claim 8, wherein the predetermined condition is that the difference between the voltage across the ac capacitor and the voltage is less than a second threshold;

the second preset condition is that the difference value between the voltage at two ends of the direct current capacitor and the voltage of the direct current bus is smaller than a third threshold value.

10. A slow start method of an energy feedback device as claimed in claim 8 or 9, further comprising:

the alternating bus voltage is adjusted to the th voltage through a transformer and is applied to the alternating current end of the controllable rectifying circuit.

Technical Field

The invention belongs to the technical field of energy feedback, and particularly relates to an energy feedback device and a slow starting method thereof.

Background

In a shutdown state of a conventional energy feedback device, the voltage of a direct current capacitor at the direct current end of the energy feedback device is zero, so that when a direct current contactor of the energy feedback device is closed, a large impact current can be generated, and the direct current contactor, a direct current hall and the direct current capacitor at the direct current end can be damaged. In addition, in a shutdown state, the voltage of the alternating current capacitor at the alternating current end of the energy feedback device is zero, and when a circuit breaker and an alternating current contactor of the energy feedback device are closed, a large impact current can be generated, so that the alternating current contactor, the alternating current hall and the alternating current capacitor at the alternating current end can be damaged.

For a conventional energy feedback device, a direct current capacitor is usually connected with a resistor in series at a direct current end to buffer an impact current generated when a direct current contactor is closed, and then the direct current is converted into alternating current through inversion of a power module to buffer the alternating current as an alternating current capacitor at an alternating current end. The direct current contactor is a high-voltage direct current contactor and is expensive, and the buffering mode brings high overall cost.

Disclosure of Invention

In view of this, embodiments of the present invention provide an energy feedback device and a slow start method thereof, so as to solve the problem of high overall cost of the prior art caused by a series resistor of a dc capacitor at a dc terminal.

The embodiment of the invention provides energy feedback devices, which comprise a circuit breaker, an alternating current contactor, a filter circuit, a power module, a direct current capacitor and a direct current contactor, wherein the end of the circuit breaker is electrically connected with an alternating current bus, and the other end is electrically connected with the power module through the alternating current contactor and the filter circuit;

the energy feedback device further comprises a controllable rectifying circuit, the alternating current end of the controllable rectifying circuit is connected between the circuit breaker and the alternating current contactor, the direct current end of the controllable rectifying circuit is connected with the direct current capacitor in parallel, the controllable rectifying circuit is used for buffering the charging of the direct current capacitor through the alternating current bus after the circuit breaker is closed, and when the voltage of two ends of the direct current capacitor reaches the th threshold value, the alternating current capacitor in the filter circuit is subjected to inversion charging through the power module, so that the direct current capacitor and the alternating current capacitor are started slowly.

Optionally, the controllable rectification circuit is a phase-controlled rectification circuit, and after phase locking, the phase-controlled rectification circuit continuously increases the duty ratio of the pulse wave driving the switching tube therein from zero to complete conduction.

Optionally, the controllable rectifier circuit is a three-phase bridge rectifier circuit, and includes an ac end, a dc end, and six thyristors, and each two of the six thyristors are connected in series and then connected in parallel;

and the connecting point between the two thyristors in each group is connected with the alternating current end, and the other ends of the two thyristors in each group are connected with the direct current end.

Optionally, the energy feedback device further includes a high-voltage switch, and the circuit breaker is electrically connected to the ac bus through the high-voltage switch.

Optionally, the energy feedback device further includes a transformer, and the transformer is disposed between the high-voltage switch and the circuit breaker.

Optionally, the energy feedback device further includes a fuse disposed between the dc capacitor and the dc contactor.

Optionally, the filter circuit includes an ac capacitor and an inductor, the inductor is disposed between the ac contactor and the power module, and the ac capacitor is disposed between the ac contactor and the inductor.

A second aspect of the embodiments of the present invention provides a slow start method for an energy feedback device, including:

closing the circuit breaker, and applying the alternating-current bus voltage to the alternating-current end of the controllable rectifying circuit;

starting the controllable rectifying circuit to perform phase control rectification on the voltage at the alternating current end and then charging the direct current capacitor through the direct current end;

when the voltage of two ends of the direct current capacitor reaches the th threshold value, the alternating current capacitor is charged through the power module;

when the voltage at two ends of the alternating current capacitor and the voltage at the alternating current end of the controllable rectifying circuit meet the th preset condition, the controllable rectifying circuit is turned off, and the alternating current contactor is closed;

after the alternating current capacitor is started slowly, the direct current capacitor is charged and boosted through the power module, so that the voltage at two ends of the direct current capacitor and the voltage of a direct current bus meet a second preset condition, and the direct current contactor is closed.

Optionally, the th preset condition is that a difference between a voltage across the ac capacitor and the th voltage is smaller than a second threshold;

the second preset condition is that the difference value between the voltage at two ends of the direct current capacitor and the voltage of the direct current bus is smaller than a third threshold value.

Optionally, the slow start method of the energy feedback device further includes:

the alternating bus voltage is adjusted to the th voltage through a transformer and is applied to the alternating current end of the controllable rectifying circuit.

The starting-up slow starting process of the energy feedback device in the embodiment of the invention is as follows:

before starting up, firstly closing the circuit breaker, wherein the voltage of the alternating current end of the controllable rectifying circuit is the power grid voltage of the alternating current bus, starting the controllable rectifying circuit, performing phase-controlled rectification, charging and buffering a direct current capacitor, and when the voltage of the two ends of the direct current capacitor reaches the th threshold value, performing inversion charging on the alternating current capacitor through a power module, and starting the alternating current capacitor slowly;

when the voltage at two ends of the alternating current capacitor and the power grid voltage of the alternating current bus (namely the voltage at the alternating current end of the controllable rectifying circuit) meet the th preset condition, the controllable rectifying circuit is turned off, the alternating current contactor is closed, and the alternating current capacitor is started slowly at the moment;

when the slow start of the alternating current capacitor is finished, the power module performs reverse rectification to charge and boost the direct current capacitor, and when the voltage at two ends of the direct current capacitor and the voltage of a direct current bus meet a second preset condition, the direct current contactor is closed, and the slow start of the direct current capacitor is finished;

at this point, the energy feedback device is started up.

According to the embodiment of the invention, the controllable rectifying circuit is used for controlling according to the timing sequence determined by , so that the direct current capacitor and the alternating current capacitor can be started without impact and slowly started after the machine is started, the components in the energy feedback device can be well protected, and the controllable rectifying circuit is low in cost, so that the cost of the whole machine is low.

Drawings

To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings according to these drawings without any creative effort.

Fig. 1 is a structural diagram of an energy feedback device according to an embodiment of the present invention;

fig. 2 is a circuit diagram of a controllable rectifying circuit according to an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

Fig. 1 shows a block diagram of an energy feedback device provided in an embodiment of the present invention, and referring to fig. 1, the energy feedback device may include a breaker Q1, an ac contactor KM2, a filter circuit 100, a power module 200, a dc capacitor C1, and a dc contactor KM 1.

The end of the breaker Q1 is used for being electrically connected with an alternating current bus, the other end is electrically connected with the power module 200 through the alternating current contactor KM2 and the filter circuit 100, the direct current capacitor C1 is connected in parallel to the direct current side of the power module 200, and the power module 200 is electrically connected with the direct current bus through the direct current contactor KM 1.

The energy feedback device further comprises a controllable rectifying circuit 300, wherein an alternating current end of the controllable rectifying circuit 300 is connected between the circuit breaker Q1 and an alternating current contactor KM2, a direct current end of the controllable rectifying circuit 300 is connected with the direct current capacitor C1 in parallel, the controllable rectifying circuit 300 is used for charging and buffering the direct current capacitor C1 through the alternating current bus after the circuit breaker Q1 is closed, and when the voltage at two ends of the direct current capacitor C1 reaches a threshold value, the alternating current capacitor C2 in the filter circuit 100 is subjected to inversion charging through the power module 200, so that the direct current capacitor and the alternating current capacitor are started slowly.

Illustratively, the start-up slow start process of the energy feedback device is as follows:

before starting, the circuit breaker Q1 is closed, at the moment, the voltage of the alternating current end of the controllable rectifying circuit 300 is the power grid voltage of an alternating current bus, the controllable rectifying circuit 300 is started and carries out phase-controlled rectification to charge and buffer the direct current capacitor C1, and when the voltage of the two ends of the direct current capacitor reaches the threshold value, the alternating current capacitor C2 is subjected to inversion charging through the power module 200, so that the alternating current capacitor C2 is started slowly;

when the voltage at the two ends of the alternating current capacitor C2 and the power grid voltage of the alternating current bus (namely the voltage at the alternating current end of the controllable rectifying circuit) meet the preset condition, the controllable rectifying circuit 300 is turned off, the alternating current contactor KM2 is closed, and at the moment, the alternating current capacitor C2 is started slowly;

after the alternating current capacitor C2 is started slowly, the power module 200 performs reverse rectification to charge and boost the direct current capacitor C1, and when the voltage at two ends of the direct current capacitor C1 and the voltage of a direct current bus meet a second preset condition, the direct current contactor KM1 is closed, and the direct current capacitor C1 is started slowly;

at this point, the energy feedback device is started up.

According to the energy feedback device, the controllable rectification circuit 300 is used for controlling according to the timing sequence determined by , so that the direct current capacitor C1 and the alternating current capacitor C2 can be started without impact and slowly, the components in the energy feedback device can be well protected, the cost of the controllable rectification circuit 300 is low, and the cost of the whole machine is low.

Optionally, referring to fig. 1, the energy feedback device may further include a high voltage switch 400, and the circuit breaker Q1 is electrically connected to the ac bus through the high voltage switch 400. Wherein, the high voltage switch 400 can improve the overall safety performance of the energy feedback device.

Optionally, referring to fig. 1, the energy feedback device may further include a transformer 500, and the transformer 500 is disposed between the high voltage switchgear 400 and the Q1. Since the voltage of the ac bus is usually high, for example, 35KV, and cannot be directly applied to the ac terminal of the ac capacitor C2 or the controllable rectifier circuit 300, the voltage of the ac bus can be transformed by the transformer 500 and adjusted to a voltage suitable for the ac terminal of the ac capacitor C2 or the controllable rectifier circuit 300, for example, 900V.

Optionally, referring to fig. 1, the energy feedback device may further include a fuse F1 disposed between the dc capacitor C1 and the dc contactor KM1, and the fuse F1 is disposed to provide safety for the energy feedback device when a current is too large, so as to further improve safety performance of the energy feedback device .

Optionally, referring to fig. 1, the filter circuit 100 may include an ac capacitor C2 and an inductor L1, the inductor L1 is disposed between the ac contactor KM2 and the power module 200, and the ac capacitor C2 is disposed between the ac contactor KM2 and the inductor L1.

Optionally, the controllable rectification circuit 300 may be a phase-controlled rectification circuit, and after phase locking, the phase-controlled rectification circuit continuously increases the duty ratio of the pulse wave driving the switching tube therein from zero to complete conduction. The switch tube may be a silicon controlled SCR switch or a full control switch, which is not limited herein.

Illustratively, the phase-controlled rectifying circuit can be a three-phase bridge rectifying circuit and comprises an alternating current end, a direct current end and six thyristors, wherein every two groups of the six thyristors are connected in series and then connected in parallel, a connecting point between two thyristors in each group is connected with the alternating current end, and the other ends of the two thyristors in each group are connected with the direct current end.

Referring to fig. 2, exemplary controllable rectifier circuit 300 may include an ac terminal a (including a1, a2 and A3), a dc terminal D, a thyristor T1, a thyristor T2, a thyristor T3, a thyristor T4, a thyristor T5 and a thyristor T6. thyristor T1 and thyristor T6 are connected in series as a group 6, thyristor T6 and thyristor T6 are connected in series as a group 6, and then the groups of thyristors are connected in parallel between 6. wherein the connection point between thyristor T6 and thyristor T6 is connected to the A6 phase terminal of the ac terminals, and the dc terminals of thyristors T6 and thyristor T6 are connected to the other 6D terminals.

For the energy feedback device, before starting up, the circuit breaker Q1 is first closed, and at this time, the ac terminal of the controllable rectification circuit 300 has 900V of grid voltage. After the controllable rectifying circuit 300 is started, phase-controlled rectification is performed to charge and buffer the dc capacitor C1, and when the highest voltage is buffered (for example, 900 × 1.414 — 1272V), the power module 100 starts inversion to charge and slowly start the ac capacitor C2;

when the voltage of the alternating current capacitor C2 is equal to the alternating current terminal voltage (900V) of the controllable rectifying circuit 300, the controllable rectifying circuit 300 is turned off, and the alternating current contactor KM2 is closed, at this time, the alternating current capacitor C2 is started slowly;

after the ac capacitor C2 is started slowly, the power module 200 performs reverse rectification to boost the dc capacitor C1, and when it is detected that the voltage across the dc capacitor C1 is equal to the traction network voltage (i.e., the dc bus voltage, for example, 1500V) , the dc contactor KM1 is closed, and the dc capacitor C1 is started slowly;

at this point, the energy feedback device is started up.

Based on any energy feedback devices, an embodiment of the present invention further provides a slow start method for an energy feedback device, where the slow start method for an energy feedback device may include:

closing the circuit breaker, and applying the alternating-current bus voltage to the alternating-current end of the controllable rectifying circuit;

starting the controllable rectifying circuit to perform phase control rectification on the voltage at the alternating current end and then charging the direct current capacitor through the direct current end;

when the voltage of two ends of the direct current capacitor reaches the th threshold value, the alternating current capacitor is charged through the power module;

when the voltage at two ends of the alternating current capacitor and the voltage at the alternating current end of the controllable rectifying circuit meet the th preset condition, the controllable rectifying circuit is turned off, and the alternating current contactor is closed;

after the alternating current capacitor is started slowly, the direct current capacitor is charged and boosted through the power module, so that the voltage at two ends of the direct current capacitor and the voltage of a direct current bus meet a second preset condition, and the direct current contactor is closed.

According to the slow start method of the energy feedback device, the direct current capacitor and the alternating current capacitor can be started slowly without impact after the power is turned on by the controllable rectifying circuit and the timing sequence control according to , so that components in the energy feedback device can be well protected, and the controllable rectifying circuit is low in cost, so that the cost of the whole machine is low.

Optionally, the voltage applied to the ac terminal of the controllable rectification circuit by the ac bus voltage is th voltage, and the th threshold value and the th voltage satisfy the relationship

Wherein x₁Is threshold value , U₁At th voltage.

Optionally, the -th preset condition may be that a difference between voltages at two ends of the ac capacitor and the -th voltage is smaller than a second threshold, and the second preset condition may be that a difference between voltages at two ends of the dc capacitor and a dc bus voltage is smaller than a third threshold, where the -th threshold may be set as needed, for example, the -th threshold is a value closer to 0, and similarly, the second threshold may be set as needed, for example, the second threshold is a value closer to 0.

Optionally, the slow start method of the energy feedback device may further include adjusting the ac bus voltage to the th voltage through a transformer, and applying the adjusted ac bus voltage to an ac terminal of the controllable rectification circuit.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill 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 substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.