阅读说明：本技术 一种pwm整流器及其短路保护装置和应用系统 (PWM rectifier and short-circuit protection device and application system thereof ) 是由 檀贵友 邹海晏 陶磊 吴云 张�杰 于 2021-07-26 设计创作，主要内容包括：本发明提供一种PWM整流器及其短路保护装置和应用系统,该PWM整流器的短路保护装置,是在PWM整流器的交流侧各相之间分别设置有至少一个分流模块,当PWM整流器的直流侧发生短路时,相应分流模块导通,对PWM整流器中反向二极管上的短路电流进行分流,避免其反向二极管承受过大的短路电流,避免其损坏,提高了PWM整流器的可靠性。(The invention provides a PWM rectifier, a short-circuit protection device and an application system thereof, wherein the short-circuit protection device of the PWM rectifier is characterized in that at least one shunt module is respectively arranged between each phase at the alternating current side of the PWM rectifier, when the direct current side of the PWM rectifier is in short circuit, the corresponding shunt module is conducted to shunt the short-circuit current on a reverse diode in the PWM rectifier, so that the reverse diode is prevented from bearing overlarge short-circuit current, the reverse diode is prevented from being damaged, and the reliability of the PWM rectifier is improved.)

1. A short-circuit protection device for a PWM rectifier, comprising: at least one shunting module; wherein:

at least one shunting module is arranged between each phase of the alternating current side of the PWM rectifier;

when the direct current side of the PWM rectifier is short-circuited, the corresponding shunt module is conducted to shunt the short-circuit current on the reverse diode in the PWM rectifier.

2. The short-circuit protection device of the PWM rectifier according to claim 1, wherein the shunt module is disposed at either end of the AC inductor of the corresponding phase on the AC side of the PWM rectifier.

3. The short-circuit protection device for the PWM rectifier according to claim 1, wherein the shunt module comprises: two anti-parallel thyristors.

4. A short-circuit protection arrangement for a PWM rectifier according to any one of claims 1-3, wherein the PWM rectifier is a three-phase rectifier, such that:

each phase of the alternating current side of the PWM rectifier is connected with one end of one corresponding shunt module; the other ends of the shunt modules are connected with each other; alternatively, the first and second electrodes may be,

and one shunt module is arranged between each phase of the alternating current side of the PWM rectifier.

5. A short-circuit protection device for a PWM rectifier according to any one of claims 1 to 3, wherein the PWM rectifier is a single-phase rectifier, then:

and one or at least two shunt modules connected in series are arranged between the live wire and the zero line on the alternating current side of the PWM rectifier.

6. A PWM rectifier, comprising: a controller and a main circuit;

the direct current side of the main circuit is used as the direct current side of the PWM rectifier;

the alternating current side of the main circuit is used as the alternating current side of the PWM rectifier, and a short-circuit protection device of the PWM rectifier according to any one of claims 1-5 is arranged on the alternating current side of the main circuit;

the main circuit is controlled by the controller.

7. An application system of a PWM rectifier, comprising: a system controller, a PWM rectifier and a short circuit protection device of the PWM rectifier according to any one of claims 1 to 5;

the alternating current side of the PWM rectifier is provided with current detection equipment, and the current detection equipment is used for detecting the alternating current of the PWM rectifier and outputting the alternating current to the system controller;

the alternating current side of the PWM rectifier is connected with an alternating current power supply through an alternating current switch;

the alternating current switch is controlled by the system controller.

8. The application of the PWM rectifier according to claim 7, wherein the system controller is configured to: and when the alternating current exceeds a threshold value, controlling the alternating current switch to be switched off, and cutting off the alternating current power supply input of the PWM rectifier.

9. Application system of a PWM rectifier according to claim 7 or 8, characterized in that the short-circuit protection means are external to the ac side of the PWM rectifier or integrated into the internal ac side of the PWM rectifier.

10. The application system of the PWM rectifier according to claim 7 or 8, wherein a fuse is further disposed between the AC switch and the AC power source.

Technical Field

The invention relates to the technical field of power electronics, in particular to a PWM rectifier, a short-circuit protection device and an application system thereof.

Background

In the prior art PWM rectifier, if the direct current side (such as DC-OUTPUT shown in fig. 1) is short-circuited, the internal parallel reverse diode will be subjected to surge in the process due to the self-sustaining capability I²t is small and cannotBearing the impact of the short-circuit current; wherein, I is the overload current, and t is the fusing time. And the damage of the reverse diode can cause the damage of the PWM rectifier, so that the whole safety and reliability of the PWM rectifier are poor, and potential safety hazards are easy to generate.

Disclosure of Invention

In view of this, the present invention provides a PWM rectifier, a short-circuit protection device thereof and an application system thereof, so as to prevent the reliability of the PWM rectifier from being reduced due to the damage of a reverse diode when a short circuit occurs on the dc side of the PWM rectifier.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

the invention provides a short-circuit protection device of a PWM rectifier, which comprises: at least one shunting module; wherein:

at least one shunting module is arranged between each phase of the alternating current side of the PWM rectifier;

when the direct current side of the PWM rectifier is short-circuited, the corresponding shunt module is conducted to shunt the short-circuit current on the reverse diode in the PWM rectifier.

Optionally, the shunt module is disposed at any end of the ac inductor corresponding to the phase on the ac side of the PWM rectifier.

Optionally, the shunting module includes: two anti-parallel thyristors.

Optionally, the PWM rectifier is a three-phase rectifier, and then:

each phase of the alternating current side of the PWM rectifier is connected with one end of one corresponding shunt module; the other ends of the shunt modules are connected with each other; alternatively, the first and second electrodes may be,

and one shunt module is arranged between each phase of the alternating current side of the PWM rectifier.

Optionally, the PWM rectifier is a single-phase rectifier, and then:

and one or at least two shunt modules connected in series are arranged between the live wire and the zero line on the alternating current side of the PWM rectifier.

A second aspect of the invention provides a PWM rectifier comprising: a controller and a main circuit;

the direct current side of the main circuit is used as the direct current side of the PWM rectifier;

the alternating current side of the main circuit is used as the alternating current side of the PWM rectifier, and the short-circuit protection device of the PWM rectifier as described in any one of the first aspect is provided;

the main circuit is controlled by the controller.

The third aspect of the present invention provides an application system of a PWM rectifier, comprising: a system controller, a PWM rectifier and a short circuit protection device for a PWM rectifier as set forth in any of the paragraphs above with respect to the first aspect;

the alternating current side of the PWM rectifier is provided with current detection equipment, and the current detection equipment is used for detecting the alternating current of the PWM rectifier and outputting the alternating current to the system controller;

the alternating current side of the PWM rectifier is connected with an alternating current power supply through an alternating current switch;

the alternating current switch is controlled by the system controller.

Optionally, the system controller is configured to: and when the alternating current exceeds a threshold value, controlling the alternating current switch to be switched off, and cutting off the alternating current power supply input of the PWM rectifier.

Optionally, the short-circuit protection device is independent of the ac side of the PWM rectifier, or integrated with the ac side of the PWM rectifier.

Optionally, a fuse is further disposed between the ac switch and the ac power supply.

The short-circuit protection device of the PWM rectifier is characterized in that at least one shunt module is arranged between each phase of the AC side of the PWM rectifier, when the DC side of the PWM rectifier is short-circuited, the corresponding shunt module is conducted to shunt short-circuit current on a reverse diode in the PWM rectifier, so that the reverse diode is prevented from bearing overlarge short-circuit current, the reverse diode is prevented from being damaged, and the reliability of the PWM rectifier is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art PWM rectifier;

fig. 2a, fig. 2b, and fig. 3 to fig. 6 are schematic diagrams of six internal and external connections of a PWM rectifier according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, 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 process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The invention provides a short-circuit protection device of a PWM rectifier, which is used for preventing a reverse diode from being damaged when a direct current side of the PWM rectifier is short-circuited so as to reduce the reliability of the PWM rectifier.

Referring to fig. 2a to 5, the short-circuit protection device of the PWM rectifier includes: at least one shunting module 101; wherein:

at least one shunt module 101 is respectively arranged between each phase of the alternating current side of the PWM rectifier, and one, two or more shunt modules 101 may be arranged between different phases, which is not limited herein, depending on the specific application environment, and is within the protection scope of the present application.

When the PWM rectifier is a three-phase rectifier, as shown in fig. 2a, each phase on the ac side of the PWM rectifier is connected to one end of a corresponding shunt module 101; and the other ends of the respective shunt modules 101 are connected to each other; i.e. the splitter modules 101 are star-connected. Or, in practical applications, one shunt module 101 may be disposed between each phase on the ac side of the PWM rectifier, that is, each shunt module 101 is connected in a delta shape (as shown in fig. 2 b).

When the PWM rectifier is a single-phase rectifier, one shunt module 101 (as shown in fig. 3) or at least two shunt modules 101 (not shown) connected in series are provided between the ac-side live wire and the neutral wire of the PWM rectifier.

Taking the structure shown in fig. 2a as an example, the short-circuit protection device has the following specific working principle:

if the DC-OUTPUT of the PWM rectifier is short-circuited at the DC side, due to the topology structure of the main circuit in the PWM rectifier, the AC power received at the AC side AC-INPUT forms a short-circuit current on the reverse diode of the internal switching tube, and at the same time, the short-circuit current is shunted due to the conduction of the corresponding shunting module 101.

It should be noted that as long as a pressure difference exists between any two phases, the shunting module 101 between the two phases can be conducted to realize shunting; the current direction on the current splitting module 101 depends on the voltage difference between the two sides of the current splitting module in real time, and is not unique.

The specific operation principle of the short-circuit protection device of the single-phase rectifier shown in fig. 3 is similar to that described above, and is not described herein again.

When the direct current side of the PWM rectifier is short-circuited, the short-circuit protection device provided by this embodiment shunts the short-circuit current on the backward diode in the PWM rectifier by the corresponding shunting module 101, so as to prevent the backward diode from bearing an excessive short-circuit current, prevent the backward diode from being damaged, and improve the reliability of the PWM rectifier.

As shown in fig. 2a to 3, the main circuit in the PWM rectifier mainly includes: a rectifier bridge formed by each switching tube, an alternating current inductor of each phase on the alternating current side of the rectifier bridge, and a direct current bus on the direct current side of the rectifier bridge; each switch tube is reversely connected with a diode in parallel, namely the reverse diode; a supporting capacitor is arranged between the positive electrode and the negative electrode of the direct current bus, a zero-voltage switch circuit is arranged on the direct current side of the direct current bus under some conditions, the specific arrangement of the main circuit can refer to the prior art, and the detailed description is omitted here.

In practical applications, each shunt module 101 may be disposed at either end of the ac inductor corresponding to the phase on the ac side of the PWM rectifier. Fig. 2a to fig. 3 show the shunt module 101 disposed at the front stage of the corresponding ac inductor as an example, in practical applications, each shunt module 101 may also be disposed between the corresponding ac inductor and the ac side of the rectifier bridge, as shown in fig. 4 and fig. 5; depending on the specific application environment, are all within the scope of the present application.

Fig. 2a, 2b, and 4 are all cases of a three-phase rectifier, but each shunt module 101 in fig. 2a and 4 is arranged in a star connection manner, so that when a short-circuit current flows between any two phases, two shunt modules 101 are connected in series to realize voltage division, and further, the voltage resistance and the type selection of each shunt module 101 are reduced, the device cost is reduced, and the arrangement manner is superior to the triangular connection manner shown in fig. 2 b.

For the case of a single-phase rectifier, if only one shunt module 101 is arranged between the zero line and the live line, the structural cost can be saved; if two or even a plurality of shunt modules 101 are arranged to be connected in series, the voltage resistance of the device can be reduced, and the cost of the device is saved; depending on the specific application environment, are all within the scope of the present application.

In practical application, each shunt module 101 can be realized by a thyristor, and the thyristor has an impedance characteristic, so that when the direct current side of the PWM rectifier is short-circuited to cause overcurrent, the thyristor is triggered to be turned on, and short-circuit current on the direct current side is shunted to the shunt module 101 formed by the thyristors, thereby avoiding damage of the backward diode.

Taking the structure shown in fig. 2a as an example, fig. 6 shows a specific structure of a shunt module 101, as shown in fig. 6, each shunt module 101 includes two thyristors connected in inverse parallel, so that no matter the voltage difference between two phases, short-circuit current shunting in the corresponding direction can be realized, and the structure is simple and the realization cost is low.

Of course, in practical applications, the shunting module 101 may also adopt other devices, and the gate triggering thereof may be implemented by any controller, which is within the protection scope of the present application.

In addition, the short-circuit protection device may be located outside the PWM rectifier, independent of the PWM rectifier, as shown in fig. 2a to 6; or may be internal to the PWM rectifier as part of the PWM rectifier topology (not shown); the specific arrangement mode can be determined according to the application environment, and is within the protection scope of the application.

Another embodiment of the present invention further provides a PWM rectifier, which mainly includes: a controller and a main circuit; wherein:

the direct current side of the main circuit is used as the direct current side of the PWM rectifier; the alternating current side of the main circuit is used as the alternating current side of the PWM rectifier, and the short-circuit protection device of the PWM rectifier according to any embodiment is arranged on the alternating current side of the main circuit; the short-circuit protection device is arranged on the alternating current side of the PWM rectifier, but realizes the direct current side short-circuit protection of the PWM rectifier; the specific structure and principle of the present invention can be found in the above embodiments, and are not described herein again.

The short-circuit protection device and the main circuit are both controlled by a controller. In practical application, the PWM rectifier can be also internally provided with a corresponding detection module so as to realize detection of corresponding parameters; other arrangements of the PWM rectifier are known in the art, and it is within the scope of the present application as long as the short-circuit protection device is disposed on either side of the ac inductor.

Another embodiment of the present invention further provides an application system of a PWM rectifier, which at least includes: a system controller, a PWM rectifier and a short-circuit protection device of the PWM rectifier as described in any one of the above embodiments; wherein:

the alternating current side of the PWM rectifier is provided with a current detection device, and the current detection device is used for detecting the alternating current of the PWM rectifier and outputting the alternating current to a system controller.

The alternating current side of the PWM rectifier is connected with an alternating current power supply through an alternating current switch; the AC switch is controlled by a system controller.

The system controller can send a turn-off signal to the alternating current switch when the alternating current exceeds a threshold value, control the alternating current switch to be switched off and cut off the alternating current power supply input of the PWM rectifier.

Before the alternating current switch is turned off, due to the existence of the short-circuit protection device, when the direct current side of the PWM rectifier is short-circuited, a shunt module in the short-circuit protection device and the PWM rectifier form a parallel connection relation to form a loop with a power grid, and short-circuit current is shunted, so that the short-circuit current flowing through the PWM rectifier is reduced, and a power device is protected.

The shunt function of the short-circuit protection device can cause the current on the alternating current side of the PWM rectifier to be increased, and further trigger the alternating current switch to be switched off; when the alternating current switch is turned off, the short-circuit current disappears.

According to the principle, the short-circuit current impact on the rectifier bridge in the direct-current side short-circuit process can be effectively reduced, and the whole system is safer and more reliable in operation.

In practical application, the application system provided in the above embodiment may be specifically a power conversion system inside a charging pile, or may be other systems, as long as the application system includes the PWM rectifier, the front stage of the PWM rectifier may further be provided with a corresponding filter, and the rear stage of the PWM rectifier may further be provided with an isolated DCDC converter, which depends on the specific application environment, and both are within the protection scope of the present application.

It should be noted that the system controller may be in communication connection with the PWM rectifier and controllers inside each of the front and rear devices thereof, so as to implement unified monitoring and management of each of the devices in the application system; or, the system controller can be integrated with controllers in other devices, and the other devices are only provided with corresponding main circuits and detection modules; depending on the specific application environment, are all within the scope of the present application.

In addition, the short-circuit protection device can be independent of the outside of the PWM rectifier, can be integrated inside the PWM rectifier, and is only required to be arranged on the PWM ac side, which is within the protection scope of the present application. The on-off of the short-circuit protection device can be controlled by any controller, and the controller with a short distance is preferred and is within the protection scope of the application.

In practical applications, a fuse is usually disposed between the ac switch and the ac power source in the application system, as shown in fig. 2a to 6.

It should be noted that, the breaking process of the ac switch, the fuse or the circuit breaker on the ac side of the PWM rectifier generally requires a certain breaking time, such as a period of ms, and during this breaking time, the current on the reverse diode in the PWM rectifier can be reduced by the shunting action of the short-circuit protection device, so as to reduce the risk of damage.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the 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. One of ordinary skill in the art can understand and implement it without inventive effort.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.