Discharge module, power electronic device, control method and computing device

Abstract

The invention relates to a discharge module, a power electronic device, a control method and a computing device. The discharging module comprises a discharging resistor, at least one normally closed switch and a normally open switch, and the normally open switch is connected with the at least one normally closed switch in parallel; and the normally open switch and the at least one normally closed switch which are connected in parallel are connected in series with the discharge resistor.

Description

Discharge module, power electronic equipment, control method and computing device Technical Field

[0001] The present disclosure generally relates to the field of circuit technology, and more particularly, to a discharge module, a power electronic device, a control method, and a computing device. Background Art

[0002] Currently, power conversion systems (PCS) are widely used for energy storage, and some DC output voltages can reach 1500V.

[0003] When the power conversion system is shut down, the energy in the DC bus support capacitors should be discharged for safety reasons. The energy stored in the capacitors is very large, but the discharge time is limited.

[0004] One current solution is to connect a large resistor in parallel with the DC bus support capacitor, allowing the stored energy to discharge through the resistor. The main disadvantage of this solution is power loss. Obviously, the discharge resistor consumes energy as long as the system is powered. To reduce power loss, a large resistor must be selected. This results in a long discharge time, which is unacceptable in most cases.

[0005] The second solution is to connect a controlled switch in series with the discharge resistor. During normal system operation, the switch is open, and the discharge resistor is inoperative. When the capacitor's energy needs to be discharged, the controlled switch is turned on to release the energy. The main disadvantage of this solution is that in an emergency, if all power is cut off and the switch cannot be turned on, the energy in the capacitor cannot be discharged.

[0006] Summary of the Invention

[0007] A brief overview of the present invention is provided below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important aspects of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is simply to present certain concepts in a simplified form as a prelude to the more detailed description discussed later.

[0008] In view of this, the present invention proposes a discharge module that can be used to discharge a DC bus support capacitor.

[0009] According to one aspect of the present disclosure, a discharge module is provided, comprising: a discharge resistor, at least one normally closed switch, and a normally open switch.

[0010] The normally open switch is connected in parallel with the at least one normally closed switch;

[0011] The normally open switch and at least one normally closed switch connected in parallel are further connected in series with the discharge resistor.

[0012] Optionally, in an example of the above aspect, the normally closed switch is a low-voltage-withstand switch device, and the normally open switch is a high-voltage-withstand switch device.

[0013] According to another aspect of the present disclosure, a power electronic device is provided, comprising at least one DC bus support capacitor and at least one discharge module as described above.

[0014] The discharge module is connected in parallel to the DC bus support capacitor, and is configured to discharge the DC bus support capacitor when the power electronic device is powered off.

[0015] According to another aspect of the present disclosure, a method for controlling a discharge module is provided, wherein the discharge module is provided in a power electronic device, the method comprising:

[0016] When the power electronic equipment is operating normally, first turn on the normally open switch of the discharge module, then turn off the normally closed switch of the discharge module, and finally turn off the normally open switch;

[0017] When the power electronic device is powered off, the normally open switch is first turned on, then the normally closed switch is turned on, and finally the normally open switch is turned off.

[0018] According to another aspect of the present disclosure, a computing device is provided, comprising: at least one processor; and a memory coupled to the at least one processor, the memory being configured to store instructions that, when executed by the at least one processor, enable the processor to perform the method described above.

[0019] According to another aspect of the present disclosure, a non-transitory machine-readable storage medium is provided, which stores executable instructions. When the instructions are executed, the machine is caused to perform the method described above.

[0020] According to another aspect of the present disclosure, a computer program is provided, comprising computer-executable instructions, which, when executed, cause at least one processor to perform the method described above.

[0021] According to another aspect of the present disclosure, a computer program product is provided, which is tangibly stored on a computer-readable medium and includes computer-executable instructions that, when executed, cause at least one processor to perform the method described above.

[0022] According to the discharge circuit of the embodiment of the present invention, no power loss will be generated under normal working conditions, thereby improving energy efficiency. When an abnormal power outage occurs in the system, the discharge resistor can be automatically connected to discharge the energy storage capacitor, thereby improving system safety. In addition, the cost of the discharge circuit is very low. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other purposes, features and advantages of the present invention will be more easily understood by referring to the following description of the embodiments of the present invention in conjunction with the accompanying drawings. The components in the accompanying drawings are only for illustrating the principles of the present invention. In the accompanying drawings, the same or similar technical features or components will be represented by the same or similar reference numerals. In the accompanying drawings:

[0024] FIG1 is an exemplary circuit topology diagram of a discharge module according to an embodiment of the present invention.

[0025] FIG2 is an exemplary circuit topology diagram of an energy storage converter according to an embodiment of the present invention.

[0026] FIG3 is a flowchart of an exemplary process of a method for controlling a discharge module according to an embodiment of the present disclosure.

[0027] FIG4 is an exemplary circuit topology diagram of a driving circuit.

[0028] FIG5 shows a block diagram of a computing device for controlling a discharge module according to an embodiment of the present disclosure.

[0029] The reference numerals are as follows: 100: discharge module R1: discharge resistor KO1: normally open switch KC1: normally closed switch 200: energy storage converter 202: AC / DC converter 204: DC bus support capacitor 300: control method for discharge module S302, S304: steps 400: drive circuit 404: first drive circuit 406: second drive circuit 4042: first signal isolator 4044: first buffer 4046: first switch driver 402: power supply 4062: second signal isolator 4064: second buffer 4066: second switch driver 500: computing device 502: processor 504: memory DETAILED DESCRIPTION

[0030] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that discussing these embodiments is intended only to enable those skilled in the art to better understand and implement the subject matter described herein, and is not intended to limit the scope of protection, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of protection of this disclosure. Various examples may omit, replace, or add various processes or components as needed. For example, the described method may be performed in an order different from the described order, and various steps may be added, omitted, or combined. In addition, features described relative to some examples may also be combined in other examples.

[0031] As used herein, the term "including" and its variations are open terms meaning "including but not limited to". The term "based on" means "based at least in part on". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0032] Regarding the second solution in the prior art, one option is to replace the normally open switch with a controlled normally closed switch. However, normally closed switches with high pull-in voltage and open-circuit voltage are difficult to select because they are typically very large and expensive.

[0033] Normally open switches with the same voltage level are cheaper and have a variety of options, such as relays and switching devices (such as IGBTs and MOSFETs).

[0034] In view of this, the present invention proposes a discharge module that can be used to discharge a DC bus support capacitor.

[0035] FIG1 shows a discharge module 100 that can be used to discharge a DC bus support capacitor according to an embodiment of the present invention.

[0036] The discharge module 100 includes a discharge resistor R1 , a normally closed switch KC1 connected in series with the discharge resistor R1 , and a normally open switch KO1 connected in parallel with the normally closed switch.

[0037] Normally closed switches can choose low-voltage switching devices, such as relays, contactors, low-voltage switching transistors, etc. Normally open switches can choose high-voltage switching devices, such as relays, contactors, high-voltage switching transistors, etc.

[0038] It is understandable that, depending on the withstand voltage level of the selected normally closed switch and the DC bus voltage, the normally closed switch can be one switch or multiple switches connected in series. In the discharge module according to the present invention, there is no limit on the number of normally closed switches.

[0039] FIG2 shows an exemplary circuit topology diagram of an energy storage converter including a discharge module according to an embodiment of the present invention.

[0040] As shown in FIG. 2 , the energy storage converter 200 includes an AC-DC converter 202 , a DC bus support capacitor 204 , and a discharge module 100 .

[0041] The AC-DC converter 202 in FIG. 2 adopts a three-level topology structure. The DC bus support capacitor 204 includes two DC bus support capacitors C1 and C2 . A discharge module 100 is connected in parallel to each DC bus support capacitor.

[0042] The circuit topology of the AC / DC converter shown in FIG2 is merely an example. Those skilled in the art may adopt any appropriate circuit topology of an AC / DC converter known in the art as needed. The specific structure of the circuit topology of the AC / DC converter in the energy storage converter of the present invention is not limited. For example, the AC / DC converter may also have a two-level topology. In this case, the energy storage converter includes only one DC bus support capacitor, with a discharge module connected in parallel to the DC bus support capacitor.

[0043] In fact, the discharge module according to the present invention can be used to discharge the DC capacitor of any power electronic device with a DC bus support capacitor, such as a power storage converter (PCS), AC-DC converter, DC-DC converter, etc., which will not be described in detail here.

[0044] In a power electronic device using a discharge module according to an embodiment of the present invention, when in normal working state, the discharge module does not perform discharge work and no power loss is generated; when the system is powered off, including when the power is off due to an emergency, the discharge module can discharge the energy storage capacitor.

[0045] The working process of the power electronic device including the discharge module according to the embodiment of the present invention will be described in detail below.

[0046] The working process of power electronic equipment includes three states: initial state, operating state and power-off state.

[0047] The initial state, also known as the power-on state, begins charging the DC bus support capacitor. In this initial state, the normally open switch KO1 is disconnected, and the normally closed switch KC1 is closed. The DC bus voltage is applied to the discharge resistor, and all switches are not subject to the pull-in voltage. After the power electronics enter normal operation, the discharge module is controlled to prevent discharge to avoid power loss. During a power outage, the discharge module is enabled to discharge the energy storage capacitor. Figure 3 below illustrates the control process of the discharge module in different states of the power electronics.

[0048] In block S302, the power electronics device is operating normally, the DC bus support capacitor has completed charging, and the discharge circuit needs to be disconnected. As mentioned above, the normally closed switch is a low-voltage switch. To reduce the voltage impact on the normally closed switch KC1 during a power outage, the normally open switch KO1 is first closed, and then the normally closed switch KC1 is disconnected. During this process, the normally closed switch is not affected by high voltage. After KC1 is disconnected, KO1 is also disconnected, preventing the discharge module from performing the discharge operation.

[0049] In block S304, the power electronics are powered off, and the energy in the DC bus support capacitors needs to be discharged. First, KO1 is controlled to be turned on, causing the discharge current to flow through R1 and KO1. Subsequently, KC1 and KC2 are also controlled to be turned on. This process is zero-voltage, with no impact on KC1 and KC2. During this turn-on process, a portion of the current gradually shifts to the KC1 and KC2 branches. Finally, KO1 is controlled to be turned off, shifting all the discharge current to the KC1 and KC2 branches. This has no voltage impact on KC1 and KC2.

[0050] A power electronic device using a discharge module according to an embodiment of the present invention can still automatically implement the discharge process in the above-mentioned power-off state even in an emergency, that is, when the power electronic device is abnormally powered off and its control part is unable to control the switch of the discharge module.

[0051] FIG4 shows a schematic circuit topology diagram of a driving circuit 400 for driving and controlling a normally closed switch and a normally open switch of a discharge module.

[0052] 4 will be used to illustrate how to automatically achieve the above-mentioned discharge process in the power-off state in an emergency.

[0053] The driving circuit 400 shown in FIG4 includes a power supply 402 , a first driving circuit 404 for driving the normally-open switch KO1 , and a second driving circuit 406 for driving the normally-closed switch KC1 .

[0054] The first drive circuit 404 includes a first signal isolator 4042, a first buffer 4044, and a first switch driver 4046. The first signal isolator 4042 is used to receive a trigger signal from the control unit of the power electronics device while isolating the control unit from the discharge module. The first buffer 4044 is used to amplify the trigger signal from the isolator. The first switch driver 4046 is used to provide the trigger signal to the normally closed switch KO1 to control it.

[0055] When the power electronic device is abnormally powered off, the drive circuit 400 cannot receive the trigger signal from the control part, but the power supply 402 can still be maintained for a period of time (for example, this can be achieved by adding a larger capacitor in the power supply).

[0056] In the driver circuit 400 according to an embodiment of the present invention, a pull-up resistor R1 and capacitor C1, or a pull-down resistor and capacitor (depending on whether the first switch driver requires a high-level trigger or a low-level trigger), are added to the first buffer 4044 or the first signal isolator 4042 of the first driver circuit 404. The pull-up resistor and capacitor or the pull-down resistor and capacitor can provide a trigger signal, which the first driver receives to connect the normally open switch KO1. Once the normally open switch KO1 is connected, the discharge process can begin.

[0057] The second driver circuit 406 for driving the normally closed switch KC1 has the same structure as the first driver circuit 404 for the normally open switch KO1, including a second signal isolator 4062, a second buffer 4064, and a second switch driver 4066. A pull-up resistor and capacitor, or a pull-down resistor and capacitor, is also added to the second buffer 4064 or second signal isolator 4062 of the second driver circuit 406 (depending on whether the second switch driver requires a high-level trigger or a low-level trigger). The second driver circuit 406 operates similarly to the first driver circuit 404, differing in the parameters of the resistors and capacitors. Because the normally open switch KO1 must be turned on first before the normally closed switch KC1 is connected, the time constant (R2*C2) of the second driver circuit for the normally closed switch KC1 must be greater than the time constant (R1*C1) of the first driver circuit. After a period of time, the power supply 402 no longer provides sufficient power to the driver circuit, and the normally closed switch KO1 loses its trigger signal and disconnects; the normally open switch KC1 remains on. The discharge operation can continue until the energy of all DC bus supporting capacitors in the discharge resistor is dissipated.

[0058] The driving circuit shown in FIG4 is only an exemplary circuit topology diagram for driving and controlling the discharge module according to the present disclosure. Those skilled in the art may select a driving circuit with an appropriate topology as needed, as long as it is possible to control the discharge module by first turning on the normally open switch, then turning on the normally closed switch, and finally turning off the normally open switch when the power electronic device is powered off.

[0059] According to the discharge circuit of the embodiment of the present invention, no power loss will be generated under normal working conditions, thereby improving energy efficiency. When an abnormal power outage occurs in the system, the discharge module can be automatically connected to discharge the energy storage capacitor, thereby improving system safety. In addition, the cost of the discharge circuit is very low.

[0060] As described above with reference to FIG. 3 , the method for controlling the discharge module in the power electronic device according to the embodiment of the present disclosure is described.

[0061] 5 shows a block diagram of a computing device 500 for controlling a discharge module in a power electronic device according to an embodiment of the present disclosure. According to one embodiment, the computing device 500 may include at least one processor 502 that executes at least one computer-readable instruction (i.e., the aforementioned elements implemented in software form) stored or encoded in a computer-readable storage medium (i.e., memory 504).

[0062] In one embodiment, computer executable instructions are stored in the memory 504 , which, when executed, enable the at least one processor 502 to perform operations performed by the control device.

[0063] It should be understood that the computer executable instructions stored in the memory 504, when executed, cause the at least one processor 502 to perform the various operations and functions described above in conjunction with FIG. 3 in various embodiments of the present disclosure.

[0064] According to one embodiment, a non-transitory machine-readable medium is provided. The non-transitory machine-readable medium may have machine-executable instructions (i.e., the elements implemented in software above), which, when executed by a machine, cause the machine to perform the various operations and functions described above in conjunction with FIG. 3 in various embodiments of the present disclosure.

[0065] According to one embodiment, a computer program is provided, including computer-executable instructions, which, when executed, enable at least one processor to perform the various operations and functions described above in conjunction with FIG. 3 in various embodiments of the present disclosure.

[0066] According to one embodiment, a computer program product is provided, including computer-executable instructions, which, when executed, cause at least one processor to perform the various operations and functions described above in conjunction with FIG. 3 in various embodiments of the present disclosure.

[0067] The specific embodiments described above in conjunction with the accompanying drawings describe exemplary embodiments, but do not represent all embodiments that can be implemented or fall within the scope of protection of the claims. The term "exemplary" used throughout this specification means "used as an example, instance or illustration" and does not mean "preferred" or "having advantages" over other embodiments. For the purpose of providing an understanding of the described technology, the specific embodiments include specific details. However, these technologies can be implemented without these specific details. In some instances, in order to avoid obscuring the concepts of the described embodiments, well-known structures and devices are shown in block diagram form.

[0068] The foregoing description of the present disclosure is provided to enable any person skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is intended to be consistent with the widest range of principles and novel features disclosed herein.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A discharge module (100), comprising: Discharge resistor (R1), at least one normally closed switch (KC1), one normally open switch (KO1), The normally open switch (KO1) is connected in parallel with the at least one normally closed switch (KC1); A normally open switch (KO1) and at least one normally closed switch (KC1) connected in parallel are further connected in series with the discharge resistor (R1).

2. The discharge module (R1) according to claim 1, wherein: The normally closed switch (KC1) is a low withstand voltage switch device, and the normally open switch (KO1) is a high withstand voltage switch device.

3. A power electronic device (200), comprising at least one DC bus support capacitor (204) and at least one discharge module (100) according to claim 1 or 2, The discharge module (100) is connected in parallel with the DC bus support capacitor (204), and the discharge module (100) is configured to discharge the DC bus support capacitor (204) when the power electronic device (200) is powered off.

4. The control method (300) of a discharge module according to claim 1 or 2, wherein the discharge module is arranged in a power electronic device, and the method comprises: When the power electronic device operates normally, first turn on the normally open switch of the discharge module, then turn off the normally closed switch of the discharge module, and finally turn off the normally open switch (S302); When the power electronic device is powered off, the normally open switch is first turned on, then the normally closed switch is turned on, and finally the normally open switch is turned off (S304).

5. A computing device (500), comprising: at least one processor (502); as well as A memory (504) coupled to the at least one processor (502), the memory being used to store instructions, which, when executed by the at least one processor (502), cause the processor (502) to perform the method as claimed in claim 4.

6. A non-transitory machine-readable storage medium storing executable instructions, which when executed cause the machine to perform the method as claimed in claim 4.

7. A computer program product tangibly stored on a computer readable medium and comprising computer executable instructions which, when executed, cause at least one processor to perform the method of claim 4.

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