Soft start circuit and input circuit of charging power supply module

Abstract

The utility model provides a soft start circuit and an input circuit of a charging power supply module. The soft start circuit comprises a switch unit, a first resistor, a second resistor and a rectification unit. As the input end of the EMI filter in the charging power supply module is connected to the alternating current power grid through the first switching device, one port of the soft start circuit is connected to the two ends of the first switching device, and the other port is connected with the bus, the charging power supply module can be switched on and off by controlling the switching unit. When the first switching device is disconnected and the EMI filter is disconnected from the power grid, the soft start circuit supplies power to the auxiliary power supply connected with the bus, meanwhile, reactive loss generated by the X capacitor is not introduced, and the stability of the circuit and the signal can be ensured through processing of the first resistor, the second resistor and the rectifying unit; during startup, the switch unit can charge the capacitor in the EMI circuit firstly, so that the impact current of the power grid side is reduced, and the safety of the first switch device is ensured.

Description

A soft-start circuit and an input circuit for a charging power supply module. Technical Field

[0001] This utility model relates to the field of power supply technology, and in particular to a soft-start circuit and an input circuit for a charging power supply module. Background Technology

[0002] In power supply equipment, the input EMI (electromagnetic interference) filter circuit is directly connected to the AC power grid, which can suppress the electromagnetic interference generated between the power supply equipment and the AC power grid, and protect the equipment itself and the power grid from interference.

[0003] As part of an EMI filter circuit, the X-capacitor suppresses differential-mode interference. However, when the power supply is not operating, if the X-capacitor remains connected to the AC grid, it will generate reactive current, which will accumulate over time, causing energy loss and line losses. Furthermore, due to the presence of the X-capacitor, when equipment is connected to the grid, the X-capacitor will charge and discharge instantaneously, generating a large inrush current, which is detrimental to the lifespan of contactors or switches. Therefore, it is necessary to improve the X-capacitor EMI filter in the charging power supply module to reduce reactive power loss during standby. Summary of the Invention

[0004] This invention provides a soft-start circuit and an input circuit for a charging power module, aiming to solve the problem of reactive power loss and device loss caused by the connection of the X capacitor to the power grid when the power module is in standby mode.

[0005] To address the aforementioned technical problems, the present invention provides a soft-start circuit, comprising: a switching unit, a first resistor, a second resistor, and a rectifier unit; one end of the first resistor is electrically connected to a first end of the switching unit, and the other end of the first resistor is electrically connected to a first switching device in an external charging power module; the second end of the switching unit is electrically connected to the input end of an EMI filter in the charging power module; the first switching device is electrically connected to the input end of the EMI filter and an AC power supply; the third end of the switching unit is electrically connected to one end of the second resistor; the other end of the second resistor is electrically connected to the first end of the rectifier unit; and the second end of the rectifier unit is electrically connected to an external bus.

[0006] Furthermore, the switching unit includes a second switching device, a first terminal of the second switching device being electrically connected to one end of the first resistor, a second terminal of the second switching device being electrically connected to the input terminal of the EMI filter, and a third terminal of the second switching device being electrically connected to one end of the second resistor.

[0007] Furthermore, the switching unit includes a second switching device and a third switching device. The first end of the second switching device is electrically connected to one end of the first resistor, the second end of the second switching device is electrically connected to the input end of the EMI filter, the third end of the second switching device is electrically connected to the first end of the third switching device, and the second end of the third switching device is electrically connected to one end of the second resistor.

[0008] Furthermore, the switching unit includes a second switching device and a third switching device. The first end of the second switching device is electrically connected to one end of the first resistor and the first end of the second switching device, respectively. The second end of the second switching device is electrically connected to the input end of the EMI filter. The second end of the third switching device is electrically connected to one end of the second resistor.

[0009] Furthermore, the rectifier unit includes a first diode and a second diode. The cathode of the first diode is electrically connected to the positive bus, the anode of the first diode is electrically connected to the second resistor and the cathode of the second diode, and the anode of the second diode is electrically connected to the negative bus.

[0010] The second aspect of this utility model provides an input circuit for a charging power module, including a soft-start circuit, an EMI filter, a rectifier bridge, and a main switching device as described in the first aspect of this utility model; the first terminal of the main switching device is electrically connected to an AC power supply and a first resistor in the soft-start circuit, the second terminal of the main switching device is electrically connected to the input terminal of the EMI filter and a second switching device in the soft-start circuit, and the rectifier bridge is electrically connected to the output terminal of the EMI filter, a bus, and a rectifier unit in the soft-start circuit.

[0011] The third aspect of this utility model provides another input circuit for a charging power module, including a soft-start circuit, an EMI filter, a rectifier bridge, a first main switch, a second main switch, and a switch module as described in the first aspect of this utility model; the first terminals of the first main switch and the second main switch are both electrically connected to an AC power source, the second terminals of the first main switch and the second main switch are both electrically connected to the input terminal of the EMI filter, the soft-start circuit is electrically connected to the first and second terminals of the first main switch, the switch module is electrically connected to the first and second terminals of the second main switch, and the rectifier bridge is electrically connected to the output terminal of the EMI filter, the bus, and the soft-start circuit, respectively.

[0012] Furthermore, the switching module includes a third resistor and a fourth switching device. One end of the third resistor is electrically connected to the first end of the second main switching device, and the fourth switching device is electrically connected to the other end of the third resistor and the second end of the second main switching device.

[0013] The fourth aspect of this utility model provides another input circuit for a charging power module, including a soft-start circuit, an EMI filter, a rectifier bridge, a first main switch device, and a second main switch device as described in the first aspect of this utility model; the first terminals of the first main switch device and the second main switch device are both electrically connected to an AC power source, the second terminals of the first main switch device and the second main switch device are both electrically connected to the input terminal of the EMI filter, the two soft-start circuits are respectively electrically connected to the first and second terminals of the corresponding main switch devices, and the rectifier bridge is respectively electrically connected to the output terminal of the EMI filter, the bus, and the two soft-start circuits.

[0014] As can be seen from the above, the input terminal of the EMI filter is connected to the AC power grid through the first switching device, while one port of the soft-start circuit of this invention is connected to both ends of the first switching device, and the other port of the soft-start circuit is connected to the bus. Thus, by controlling the opening and closing of the switching unit, when the first switching device is open and the EMI filter is disconnected from the power grid, the soft-start circuit can supply power to the auxiliary power supply connected to the bus to power the devices in the power module, while avoiding the reactive power loss generated by the X capacitor. Furthermore, through the processing of the first resistor, the second resistor, and the rectifier unit, the stability of the line and signal can be guaranteed. During power-on, the switching unit can first charge the capacitor in the EMI circuit to reduce the inrush current on the power grid side and ensure the safety of the first switching device. Attached Figure Description

[0015] Figure 1 is a schematic diagram of a soft-start circuit according to an embodiment of the present invention;

[0016] Figure 2 is a circuit diagram of the first soft-start circuit according to an embodiment of the present invention;

[0017] Figure 3 is a circuit diagram of the second soft-start circuit according to an embodiment of the present invention;

[0018] Figure 4 is a circuit diagram of the third soft-start circuit according to an embodiment of the present invention;

[0019] Figure 5 is a circuit diagram of the input circuit of the first type of charging power module according to an embodiment of the present invention.

[0020] Figure 6 is a circuit diagram of the input circuit of the second type of charging power module according to an embodiment of the present invention;

[0021] Figure 7 is a circuit diagram of the input circuit of the third type of charging power module according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Throughout the description, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0023] In related technologies, there are problems such as reactive power loss and device loss caused by the X capacitor being connected to the power grid when the power module is in standby mode. Therefore, this utility model embodiment provides a soft-start circuit.

[0024] Figure 1 shows a schematic diagram of a soft-start circuit provided in an embodiment of the present invention. The soft-start circuit includes a switching unit, a first resistor, a second resistor, and a rectifier unit. One end of the first resistor is electrically connected to the first end of the switching unit, and the other end of the first resistor is electrically connected to the first switching device in the external charging power module. The second end of the switching unit is electrically connected to the input end of the EMI filter in the charging power module. The first switching device is electrically connected to the input end of the EMI filter and the AC power supply. The third end of the switching unit is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to the first end of the rectifier unit. The second end of the rectifier unit is electrically connected to the external bus.

[0025] Specifically, in the charging power module, the input terminal of the EMI filter is connected to the AC power grid through the first switching device. In this embodiment, one port of the soft-start circuit is connected to both ends of the first switching device, and the other port of the soft-start circuit is connected to the bus. Thus, by controlling the opening and closing of the switching unit, when the first switching device is open and the EMI filter is disconnected, the soft-start circuit can supply power to the auxiliary power supply connected to the bus to power the devices in the power module. At the same time, it will not introduce the reactive power loss generated by the X capacitor. Furthermore, through the processing of the first resistor, the second resistor, and the rectifier unit, the stability of the line and signal can be guaranteed. When it is necessary to connect to the power grid, the switching unit can first charge the capacitor in the EMI circuit, thereby reducing the inrush current on the power grid side, enabling the first switching device to soft-start, and ensuring the safety of the first switching device.

[0026] Figure 2 shows the circuit diagram of the first soft-start circuit provided in this embodiment of the present invention. Please refer to Figure 2. The switching unit includes a second switching device RLY2. The first end of the second switching device is electrically connected to one end of the first resistor R2. The second end of the second switching device RLY2 is electrically connected to the input end of the EMI filter. The third end of the second switching device RLY2 is electrically connected to one end of the second resistor R1.

[0027] Specifically, in this embodiment, the switching unit includes a switching device, which can be a relay, such as a single-pole double-throw relay. When the charging power module is in standby mode, to disconnect the X capacitor in the EMI filter, the first switching device is disconnected, thus disconnecting the EMI filter from the AC power grid. The X capacitor cannot form a loop, preventing reactive power loss. To prevent the auxiliary power supply from failing to power the internal components of the module after the EMI filter is disconnected, the soft-start circuit in this embodiment can also control the connection between the first and third terminals of the second switching device RLY2, and disconnect the connection between the first and second terminals of the second switching device RLY2. At this time, the AC input can supply power to the bus through the first resistor R2, the second switching device RLY2, the second resistor R1, and the rectifier unit, enabling the auxiliary power supply connected to the bus to operate normally. During power-on, by closing the second switching device RLY2, the first and second terminals of the second switching device RLY2 are connected. This charges the capacitor in the EMI filter, reducing the inrush current on the power grid side and simultaneously reducing the voltage across the first switching device. Then, the first switching device is closed, enabling a soft start and ensuring its safety.

[0028] Figure 3 shows the circuit diagram of the second soft-start circuit provided in this embodiment of the present invention. Referring to Figure 3, the switching unit includes a second switching device RLY2 and a third switching device RLY1. The first end of the second switching device RLY2 is electrically connected to one end of the first resistor R2. The second end of the second switching device RLY2 is electrically connected to the input end of the EMI filter. The third end of the second switching device RLY2 is electrically connected to the first end of the third switching device RLY1. The second end of the third switching device RLY1 is electrically connected to one end of the second resistor R1.

[0029] Specifically, in this embodiment, the switching unit includes two switching devices, with a third switching device RLY1 connected to the third terminal of the second switching device RLY2. In standby mode, by connecting the first and third terminals of the second switching device RLY2 and closing the third switching device RLY1, AC input can supply power to the bus through the first resistor R2, the third switching device RLY1, the second resistor R1, and the rectifier unit, allowing the auxiliary power supply connected to the bus to operate normally. In standby mode, the first switching device is disconnected, preventing the X capacitor from forming a loop and eliminating reactive power loss. During power-on, by connecting the first and second terminals of the second switching device RLY2, the capacitor in the EMI filter can be charged, reducing the inrush current on the grid side and simultaneously reducing the voltage across the first switching device. Then, the first switching device is closed, enabling a soft start and ensuring its safety. In this embodiment, by using two switching devices, the reliability of the soft-start circuit supplying power to the auxiliary power supply can be improved.

[0030] Figure 4 shows the circuit schematic of the third soft-start circuit provided in this embodiment of the present invention. Please refer to Figure 4. The switching unit includes a second switching device RLY2 and a third switching device RLY1. The first end of the second switching device RLY2 is electrically connected to one end of the first resistor R2 and the first end of the second switching device RLY2, respectively. The second end of the second switching device RLY2 is electrically connected to the input end of the EMI filter. The second end of the third switching device RLY1 is electrically connected to one end of the second resistor R1.

[0031] Specifically, in this embodiment, the switching unit includes two switching devices, with a third switching device RLY1 connected to the first terminal of the second switching device RLY2. In standby mode, by disconnecting the first and second terminals of the second switching device RLY2 and closing the third switching device RLY1, AC input can supply power to the bus through the first resistor R2, the third switching device RLY1, the second resistor R1, and the rectifier unit, allowing the auxiliary power supply connected to the bus to operate normally. In standby mode, the first switching device is disconnected, preventing the X capacitor from forming a circuit and eliminating reactive power loss. During power-on, by connecting the first and second terminals of the second switching device RLY2, the capacitor in the EMI filter can be charged, reducing the inrush current on the mains side and simultaneously reducing the voltage across the first switching device. Then, the first switching device is closed, enabling a soft start and ensuring its safety. In this embodiment, by connecting the third switching device RLY1 to the first terminal of the second switching device RLY2 and keeping the third switching device RLY1 normally closed, auxiliary power can be supplied during power-on.

[0032] Further, please refer to Figures 2 to 4. The rectifier unit includes a first diode D1 and a second diode D2. The cathode of the first diode D1 is electrically connected to the positive bus, the anode of the first diode D1 is electrically connected to the second resistor R1 and the cathode of the second diode D2, and the anode of the second diode D2 is electrically connected to the negative bus.

[0033] Specifically, the rectifier unit in this embodiment includes two diodes connected in series. The two ends of the rectifier unit are connected to the positive and negative busbars. Through the function of the rectifier unit, the voltage input to the busbars can be made more stable.

[0034] Figure 5 shows the circuit diagram of the input circuit of the first charging power module provided in this embodiment of the present invention. The input circuit includes the soft start circuit 100, the EMI filter 200, the rectifier bridge 300 and the main switch device RLY3. The first terminal of the main switch device RLY3 is electrically connected to the AC power supply and the first resistor R2 in the soft start circuit 100. The second terminal of the main switch device RLY3 is electrically connected to the input terminal of the EMI filter 200 and the second switch device RLY2 in the soft start circuit 100. The rectifier bridge 300 is electrically connected to the output terminal of the EMI filter 200, the bus and the rectifier unit in the soft start circuit 100.

[0035] Specifically, in this embodiment, one port of the soft-start circuit 100 is connected to both ends of the main switching device RLY3 in the input circuit of the charging power module, and the other port of the circuit is connected to both ends of the bus. In standby mode, the connection between the second switching device RLY2 and the main switching device RLY3 is disconnected, and the first switching device is disconnected. The X capacitor cannot form a loop and no reactive power loss is generated. The AC input supplies power to the bus through the first resistor R2, the switching unit, the second resistor R1, and the rectifier unit, so that the auxiliary power supply connected to the bus can work normally. When powered on, by connecting the switching unit to the main switching device RLY3, the capacitor in the EMI filter 200 can be charged, thereby reducing the inrush current on the grid side and reducing the voltage across the first switching device. Then, the first switching device is closed, so that the first switching device is soft-started, ensuring the safety of the first switching device.

[0036] Figure 6 shows the circuit diagram of the input circuit of the second type of charging power module provided in this embodiment of the present invention. The input circuit includes the soft-start circuit 100, EMI filter 200, rectifier bridge 300, first main switch device RLY3, second main switch device RLY5, and switch module 400. The first terminals of the first main switch device RLY3 and the second main switch device RLY5 are both electrically connected to the AC power supply. The second terminals of the first main switch device RLY3 and the second main switch device RLY5 are both electrically connected to the input terminal of the EMI filter 200. The soft-start circuit 100 is electrically connected to the first and second terminals of the first main switch device RLY3. The switch module 400 is electrically connected to the first and second terminals of the second main switch device RLY5. The rectifier bridge 300 is electrically connected to the output terminal of the EMI filter 200, the bus, and the soft-start circuit 100.

[0037] Furthermore, the switching module 400 includes a third resistor R3 and a fourth switching device RLY4. One end of the third resistor is electrically connected to the first end of the second main switching device RLY5, and the fourth switching device is electrically connected to the other end of the third resistor and the second end of the second main switching device RLY5. The third resistor can be used for current limiting.

[0038] Specifically, in this embodiment, the soft-start circuit 100 can also be applied to a three-phase input circuit, and is connected only in one phase input. In standby mode, its operating principle is similar to the first type of input circuit described above. Upon power-on, the switching unit in the soft-start circuit 100 is first connected to the first main switching device RLY3, and simultaneously the fourth switching device is connected to the second main switching device RLY5 to charge the capacitor in the EMI circuit, reducing the grid-side inrush current and simultaneously reducing the voltage across the main switching devices. Then, the two main switching devices are closed to achieve a soft start, ensuring the safety of the switching devices.

[0039] Figure 7 shows the circuit diagram of the input circuit of the third type of charging power module provided in this embodiment of the present invention. The input circuit includes two soft-start circuits 100, an EMI filter 200, a rectifier bridge 300, a first main switch device RLY3, and a second main switch device RLY5. The first terminals of the first main switch device RLY3 and the second main switch device RLY5 are both electrically connected to the AC power supply, and the second terminals of the first main switch device RLY3 and the second main switch device RLY5 are both electrically connected to the input terminal of the EMI filter 200. The two soft-start circuits 100 are respectively electrically connected to the first and second terminals of the corresponding main switch devices. The rectifier bridge 300 is respectively electrically connected to the output terminal of the EMI filter 200, the bus, and the two soft-start circuits 100.

[0040] Specifically, in this embodiment, for the three-phase input circuit, the aforementioned soft-start circuit 100 can also be connected to two phase inputs respectively. Its power-on and standby operating principles are the same as the first and second input circuits described above, and will not be repeated here. By adding the aforementioned soft-start circuit 100 to the multi-phase inputs, the charging of the bus capacitor can be accelerated, thereby shortening the power-on time.

[0041] The soft-start circuit provided in this embodiment of the invention has one port connected to both ends of the first switching device and the other port connected to the bus. Thus, by controlling the opening and closing of the switching unit, when the first switching device is open and the EMI filter is disconnected, the soft-start circuit can supply power to the auxiliary power supply connected to the bus to power the devices in the power module. At the same time, it will not introduce the reactive power loss generated by the X capacitor. Furthermore, through the processing of the first resistor, the second resistor, and the rectifier unit, the stability of the line and signal can be guaranteed. When it is necessary to connect to the power grid, the switching unit can first charge the capacitor in the EMI circuit to reduce the inrush current on the power grid side and ensure the safety of the first switching device.

[0042] It should be noted that the various embodiments in this utility model are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0043] It should also be noted that, in the present invention, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in the present invention may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not 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.

Claims

1. A soft-start circuit, characterized in that, include: The system comprises a switching unit, a first resistor, a second resistor, and a rectifier unit. One end of the first resistor is electrically connected to a first end of the switching unit, and the other end of the first resistor is electrically connected to a first switching device in an external charging power module. The second end of the switching unit is electrically connected to the input end of an EMI filter in the charging power module. The first switching device is electrically connected to the input end of the EMI filter and an AC power supply. The third end of the switching unit is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to a first end of the rectifier unit. The second end of the rectifier unit is electrically connected to an external bus.

2. The soft-start circuit according to claim 1, characterized in that, The switching unit includes a second switching device, a first terminal of the second switching device being electrically connected to one end of the first resistor, a second terminal of the second switching device being electrically connected to the input terminal of the EMI filter, and a third terminal of the second switching device being electrically connected to one end of the second resistor.

3. The soft-start circuit according to claim 1, characterized in that, The switching unit includes a second switching device and a third switching device. The first end of the second switching device is electrically connected to one end of the first resistor, the second end of the second switching device is electrically connected to the input end of the EMI filter, the third end of the second switching device is electrically connected to the first end of the third switching device, and the second end of the third switching device is electrically connected to one end of the second resistor.

4. The soft-start circuit according to claim 1, characterized in that, The switching unit includes a second switching device and a third switching device. The first end of the second switching device is electrically connected to one end of the first resistor and the first end of the second switching device, respectively. The second end of the second switching device is electrically connected to the input end of the EMI filter. The second end of the third switching device is electrically connected to one end of the second resistor.

5. The soft-start circuit according to any one of claims 1 to 4, characterized in that, Both the first switching device and the switching device in the switching unit are relays.

6. The soft-start circuit according to claim 1, characterized in that, The rectifier unit includes a first diode and a second diode. The cathode of the first diode is electrically connected to the positive bus, the anode of the first diode is electrically connected to the second resistor and the cathode of the second diode, and the anode of the second diode is electrically connected to the negative bus.

7. An input circuit for a charging power module, characterized in that, It includes a soft-start circuit, an EMI filter, a rectifier bridge, and a main switching device as described in any one of claims 1 to 6; the first terminal of the main switching device is electrically connected to an AC power supply and a first resistor in the soft-start circuit, the second terminal of the main switching device is electrically connected to the input terminal of the EMI filter and a second switching device in the soft-start circuit, and the rectifier bridge is electrically connected to the output terminal of the EMI filter, the bus, and the rectifier unit in the soft-start circuit.

8. An input circuit for a charging power module, characterized in that, The device includes a soft-start circuit, an EMI filter, a rectifier bridge, a first main switch, a second main switch, and a switch module as described in any one of claims 1 to 6; the first terminals of the first main switch and the second main switch are both electrically connected to an AC power supply, the second terminals of the first main switch and the second main switch are both electrically connected to the input terminal of the EMI filter, the soft-start circuit is electrically connected to the first and second terminals of the first main switch, the switch module is electrically connected to the first and second terminals of the second main switch, and the rectifier bridge is electrically connected to the output terminal of the EMI filter, the bus, and the soft-start circuit, respectively.

9. The input circuit according to claim 8, characterized in that, The switching module includes a third resistor and a fourth switching device. One end of the third resistor is electrically connected to the first end of the second main switching device, and the fourth switching device is electrically connected to the other end of the third resistor and the second end of the second main switching device.

10. An input circuit for a charging power module, characterized in that, The device includes two soft-start circuits as described in any one of claims 1 to 6, an EMI filter, a rectifier bridge, a first main switch, and a second main switch; the first terminals of both the first and second main switches are electrically connected to an AC power supply, and the second terminals of both the first and second main switches are electrically connected to the input terminal of the EMI filter; the two soft-start circuits are respectively electrically connected to the first and second terminals of their respective main switches; and the rectifier bridge is respectively electrically connected to the output terminal of the EMI filter, the bus, and the two soft-start circuits.

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