Pre-charging circuit applied to inverter and inverter
By connecting a voltage source and bus capacitor to the power supply bus of the inverter and setting up a pre-charging circuit to pre-charge the bus capacitor, the problems of high cost and poor safety of pre-charging circuits in the prior art are solved, thereby achieving cost reduction and safety improvement.
Patent Information
- Application Number
- CN202520424063.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2026-02-13
- Estimated Expiration
- 2035-03-11
AI Technical Summary
In existing technologies, the pre-charge circuit of the inverter is located between the inverter module and the AC power supply, resulting in high cost and poor safety.
A voltage source and a bus capacitor are connected to the power supply bus of the inverter, and a pre-charging circuit is set on the connection line between the bus capacitor and the power supply bus. The power source's electrical energy is pre-charged to the bus capacitor through the pre-charging circuit, avoiding direct connection to the AC power supply.
Costs were reduced and safety was improved by replacing power relays with signal relays, which reduced the power requirements of the relays and enhanced the safety of the system.
Smart Images
Figure CN223912413U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of inverters, in particular to a pre-charge circuit applied to an inverter and the inverter. BACKGROUND
[0002] The bus capacitor in the inverter is arranged between a direct-current power supply and an inverter module, and the inverter module is used for connecting an alternating-current power supply. When the inverter works, the alternating-current power supply charges the bus capacitor instantaneously through the inverter module, at this time, the current flowing through the bus capacitor is large, which is easy to damage the inverter module.
[0003] In the prior art, in order to reduce the influence of the current, a pre-charge circuit is arranged between the inverter module and the alternating-current power supply. When the alternating-current power supply is connected, the pre-charge circuit is used to pre-charge the bus capacitor, so as to reduce the current flowing through the inverter module and the bus capacitor, and the pre-charge is ended when the voltage across the bus capacitor reaches a preset voltage. However, since the above scheme only realizes pre-charge through the alternating-current power supply, the alternating-current power supply is generally a power grid, so the relay must be able to withstand high power, and the relay can only select a power relay, which has high cost. Moreover, since the pre-charge circuit is arranged between the inverter module and the alternating-current power supply, when the pre-charge circuit has a problem, the safety of the inverter is affected. CONTENT OF THE UTILITY MODEL
[0004] Therefore, the purpose of the present application is to provide a pre-charge circuit applied to an inverter and the inverter, which can connect a voltage source and a bus capacitor on a power supply bus of the inverter, and arrange a pre-charge circuit on a connection line between the bus capacitor and the power supply bus connected thereto, so as to pre-charge the bus capacitor by the pre-charge circuit through the electric energy of the voltage source connected to the power supply bus, thereby solving the technical problem of high cost and poor safety caused by the pre-charge circuit arranged between the inverter module and the alternating-current power supply in the prior art, and achieving the technical effects of reducing cost and improving safety.
[0005] In a first aspect, an embodiment of the present application provides a pre-charge circuit applied to an inverter, the inverter comprising a bus capacitor, an inverter module and a power supply bus, wherein one end of the bus capacitor is used for connecting at least one direct-current power supply, the other end of the bus capacitor is connected to a direct-current side of the inverter module, an alternating-current side of the inverter module is used for connecting an alternating-current power supply, the power supply bus is connected to the other end of the bus capacitor and a voltage source to receive electric energy, and the power supply bus is also connected to the inverter module to supply power to the inverter module, wherein the pre-charge circuit is arranged between the bus capacitor and the power supply bus, and the pre-charge circuit is used to pre-charge the bus capacitor by electric energy of the voltage source.
[0006] Optionally, the pre-charge circuit comprises a relay and a pre-charge resistor, the relay and the pre-charge resistor are connected in parallel, wherein whether the pre-charge resistor is short-circuited is controlled by the on-off state of the relay, and when the pre-charge resistor is not short-circuited, the power of the voltage source pre-charges the bus capacitor through the pre-charge resistor.
[0007] Optionally, the pre-charge circuit further comprises a first diode, the first diode and the pre-charge resistor are connected in series, wherein the cathode of the first diode is the electrode of the first diode closer to the bus capacitor, and the anode of the first diode is the electrode of the first diode farther away from the bus capacitor.
[0008] Optionally, the inverter further comprises an auxiliary power supply, the auxiliary power supply is arranged between the inverter module and the power supply bus, wherein the auxiliary power supply is used to provide the power on the power supply bus to the inverter module to supply power to the inverter module.
[0009] Optionally, the relay comprises a signal relay.
[0010] Optionally, the pre-charge resistor comprises any one of a metal film resistor, a carbon film resistor, a cement resistor and a thermistor.
[0011] In a second aspect, the embodiments of the present application further provide an inverter, the inverter comprising the pre-charge circuit described in the first aspect or any possible implementation manner of the first aspect.
[0012] Optionally, the voltage source comprises a plurality of voltage sources, the plurality of voltage sources comprises a battery flyback power supply and a grid flyback power supply.
[0013] Optionally, the inverter further comprises a plurality of second diodes, one second diode is arranged between each voltage source and the power supply bus, the anode of the second diode is the electrode of the second diode closer to its corresponding voltage source, and the cathode of the second diode is the electrode of the second diode farther away from its corresponding voltage source.
[0014] Optionally, the power supply bus is further used to access a photovoltaic output end, and the inverter further comprises a third diode, the third diode is arranged between the photovoltaic output end and the power supply bus, wherein the anode of the third diode is the electrode of the third diode closer to the photovoltaic output end, and the cathode of the third diode is the electrode of the third diode farther away from the photovoltaic output end.
[0015] The pre-charging circuit and the inverter provided by the embodiment of the present application are applied to the inverter, and the inverter comprises a bus capacitor, an inverter module and a power supply bus, wherein one end of the bus capacitor is used for connecting at least one direct-current power supply, the other end of the bus capacitor is connected to the direct-current side of the inverter module, the alternating-current side of the inverter module is used for connecting an alternating-current power supply, the power supply bus is connected to the other end of the bus capacitor and a voltage source to receive electric energy, and the power supply bus is also connected to the inverter module to supply power to the inverter module. The pre-charging circuit is arranged between the bus capacitor and the power supply bus, and the electric energy of the voltage source is used to pre-charge the bus capacitor. The voltage source and the bus capacitor are connected to the power supply bus of the inverter, and the pre-charging circuit is arranged on the connecting line between the bus capacitor and the power supply bus connected to the bus capacitor, so that the electric energy of the voltage source connected to the power supply bus is used to pre-charge the bus capacitor through the pre-charging circuit. The technical problem of high cost and poor safety caused by the pre-charging circuit arranged between the inverter module and the alternating-current power supply in the prior art is solved, and the technical effects of reducing cost and improving safety are achieved.
[0016] In order to make the above objectives, characteristics and advantages of the present application more apparent, clear and easy to understand, the following will specifically describe the preferred embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0018] Figure 1 A schematic diagram of the pre-charging circuit provided in the prior art is shown.
[0019] Figure 2 A schematic diagram of the inverter provided by the embodiment of the present application is shown.
[0020] Figure 3 A circuit diagram of the pre-charging circuit applied to the inverter provided by the embodiment of the present application is shown. DETAILED DESCRIPTION
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.
[0022] In the prior art, please refer to Figure 1 , Figure 1 This is a schematic diagram of a pre-charging circuit in the prior art provided in the embodiments of this application. Figure 1 As shown, the inverter module 101 of the inverter is located between the DC power supply 102 and the AC power supply 103. A bus capacitor C1 is located between the inverter module 101 and the DC power supply 102, forming a pre-charge circuit 104. The inverter module converts the DC power from the DC power supply to AC power and connects it to the AC power supply. The DC power supply's energy is reduced by the bus capacitor to minimize voltage fluctuations and provides a momentary surge of energy, allowing the inverter module to supply a more standard sine wave to the AC power supply. The pre-charge circuit includes a power relay S1 and a pre-charge resistor R1. When the power relay is off, the pre-charge resistor is connected to the circuit, reducing the current flowing into the inverter module and the bus capacitor, and pre-charging the bus capacitor. Pre-charging ends when the voltage across the bus capacitor reaches a preset voltage. Upon termination of pre-charging, the power relay is activated, short-circuiting the pre-charge resistor to prevent it from affecting the power flowing into the AC power supply.
[0023] Since the above solution relies solely on AC power for pre-charging, which is typically the mains power, the relays must be capable of handling high power. This necessitates the selection of power relays, resulting in higher costs. Furthermore, because the pre-charging circuit is located between the inverter module and the AC power supply, problems in the pre-charging circuit can compromise the inverter's safety.
[0024] To address the aforementioned problems, this application provides a pre-charging circuit and inverter for use in an inverter. By connecting a voltage source and a bus capacitor to the inverter's power supply bus, and setting a pre-charging circuit on the connection line between the bus capacitor and the connected power supply bus, the pre-charging circuit pre-charges the bus capacitor with the electrical energy from the voltage source connected to the power supply bus. This solves the technical problems of high cost and poor safety caused by placing the pre-charging circuit between the inverter module and the AC power supply in the prior art, achieving the technical effects of reducing costs and improving safety. Specifically:
[0025] Please see Figure 2 , Figure 2 This is a schematic diagram of an inverter provided in an embodiment of this application. Figure 2 As shown in the embodiment of this application, the inverter includes a bus capacitor C2, an inverter module 201, and a power supply bus BUS. One end of the bus capacitor is connected to at least one DC power supply 202, and the other end of the bus capacitor is connected to the DC side of the inverter module. The AC side of the inverter module is connected to an AC power supply 203. The power supply bus connects the other end of the bus capacitor and a voltage source 205 to receive electrical energy. The power supply bus also connects to the inverter module to supply power to the inverter module. The pre-charging circuit 204 is disposed between the bus capacitor and the power supply bus to pre-charge the bus capacitor with electrical energy from the voltage source.
[0026] The inverter further includes an auxiliary power supply V, which is located between the inverter module and the power supply bus. The auxiliary power supply is used to provide electrical energy from the power supply bus to the inverter module to supply power to the inverter module.
[0027] In other words, for each DC power source, the electrical energy flows into the inverter module through the bus capacitor. The inverter module converts the DC power from the DC power source into AC power before inputting it into the AC power supply. For example, the DC power source can be a combination of a photovoltaic panel and a DC-DC converter, where the DC-DC converter converts the electrical energy generated by the photovoltaic panel before outputting it to the bus capacitor. The DC power source can also be a battery pack. The AC power source can be the power grid.
[0028] Specifically, the auxiliary power supply's power terminal can be understood as receiving electrical energy to supply power to the various electrical components of the inverter module, thus energizing the inverter module. In other words, the auxiliary power supply's power terminal is connected to the power supply bus, and its output terminal is connected to the inverter module's power terminal. Therefore, the auxiliary power supply load provides electrical energy from the power supply bus to the inverter module, enabling it to start operating and converting the DC power from the DC power supply into AC power for input into the AC power supply.
[0029] Exemplarily, the power supply end of the auxiliary power supply is connected to the power supply bus, the other end of the bus capacitor, and the voltage source. In this way, the power received by the power supply end of the auxiliary power supply can be provided by the voltage source, the DC power supply 202 connected through the bus capacitor, or both the voltage source and the DC power supply. The present application does not limit this.
[0030] Further, before the inverter module of the inverter is connected to the AC power supply, the pre-charging circuit is controlled to start pre-charging to charge the bus capacitor. The voltage source can change the current size for charging the bus capacitor by controlling the output power, so as to protect the bus capacitor. When the voltage across the bus capacitor reaches the pre-charging end indication voltage, it means that the bus capacitor is fully charged, and the pre-charging circuit is controlled to end pre-charging, and then the inverter module of the inverter is connected to the AC power supply. In this way, the pre-charging of the bus capacitor is realized through the transmission loop of the voltage source, the power supply bus, the pre-charging circuit, and the bus capacitor, avoiding the technical problems of high cost and low safety caused by directly setting the pre-charging circuit between the inverter module and the AC power supply.
[0031] The inverter module can be implemented by a DC-AC converter (DCAC). The present application does not limit the specific circuit of the inverter module, and the inverter module only needs to realize the function of converting DC power into AC power.
[0032] As shown in Figure 3 The pre-charging circuit 204 applied to the inverter provided by the present application includes a relay S2 and a pre-charging resistor R2, which are connected in parallel. The on-off state of the relay is used to control whether the pre-charging resistor is short-circuited. When the pre-charging resistor is not short-circuited, the power of the voltage source is used to pre-charge the bus capacitor through the pre-charging resistor.
[0033] That is, the on-off state of the relay includes the open state and the attracted state. When the relay is in the open state, the pre-charging resistor is not short-circuited, and the pre-charging circuit starts to charge the bus capacitor. When the relay is in the attracted state, the pre-charging resistor is short-circuited, and the pre-charging circuit ends the pre-charging of the bus capacitor. In this way, the pre-charging of the bus capacitor can be controlled by controlling the on-off state of the relay in the pre-charging circuit.
[0034] Exemplarily, the relay includes a signal relay. The pre-charging resistor includes any one of a metal film resistor, a carbon film resistor, a cement resistor, and a thermistor. That is, the voltage source is used to pre-charge the bus capacitor, and the voltage source also needs to supply power to the auxiliary power supply. The output power of the voltage source is small, and therefore only a signal relay needs to be selected. The cost of the signal relay is less than that of a power relay, which reduces the cost.
[0035] Referring to Figure 3 , Figure 3 A circuit diagram of a pre-charge circuit applied to an inverter is provided in the embodiments of the present application. As Figure 3 shown, the pre-charge circuit 204 further comprises a first diode D1, which is connected in series with the pre-charge resistor, wherein the cathode of the first diode is the electrode of the two electrodes of the first diode closer to the bus capacitor, and the anode of the first diode is the electrode of the two electrodes of the first diode farther from the bus capacitor.
[0036] Further, when charging the bus capacitor, the electric energy of the voltage source flows into the bus capacitor through the first diode and the pre-charge resistor, and the first diode can limit the current direction and improve safety.
[0037] Specifically, the voltage source comprises a plurality of voltage sources, and the plurality of voltage sources comprise a battery flyback power supply and a grid flyback power supply. The inverter further comprises a plurality of second diodes, and one second diode is arranged between each voltage source and the power supply bus, wherein the anode of the second diode is the electrode of the two electrodes of the second diode closer to its corresponding voltage source, and the cathode of the second diode is the electrode of the two electrodes of the second diode farther from its corresponding voltage source.
[0038] As Figure 3 shown, the grid flyback power supply is connected to the power supply bus through its corresponding second diode D2, and the battery flyback power supply is connected to the power supply bus through its corresponding second diode D3. The actual voltage source providing electric energy to the power supply bus can be only one voltage source, or the power supply can be only through the bus capacitor, or the power supply can be a mixture of the voltage source and the bus capacitor, and no limitation is made in this regard. The second diode is arranged to prevent the electric energy on the power supply bus from flowing back to the voltage source, thereby increasing the safety of the inverter.
[0039] As Figure 3 shown, the power supply bus is also used to connect a photovoltaic output end, and the inverter further comprises a third diode D4 arranged between the photovoltaic output end and the power supply bus, wherein the anode of the third diode is the electrode of the two electrodes of the third diode closer to the photovoltaic output end, and the cathode of the third diode is the electrode of the two electrodes of the third diode farther from the photovoltaic output end.
[0040] That is, the power supply bus can be provided with power through the output end of the power supply composed of the photovoltaic panel and the DC-DC converter, but since the photovoltaic panel is equivalent to a current source, the current output by the photovoltaic panel is stable and cannot charge the bus capacitor, and further, the photovoltaic output end cannot pre-charge the bus capacitor. Only after the bus capacitor is pre-charged by the battery flyback power supply or the grid flyback power supply, the photovoltaic output end is connected to the power supply bus, and the auxiliary power supply is powered by the power provided by the photovoltaic panel.
[0041] In the description of the present application, it should be noted that the terms "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0042] It should also be noted that unless otherwise explicitly specified and limited, the terms "provided", "connected" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0043] The above only describes the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A pre-charge circuit applied to an inverter, characterized by, The inverter comprises a bus capacitor, an inverter module and a power supply bus, wherein one end of the bus capacitor is used for connecting at least one direct-current power supply, the other end of the bus capacitor is connected to a direct-current side of the inverter module, an alternating-current side of the inverter module is used for connecting an alternating-current power supply, the power supply bus is connected to the other end of the bus capacitor and a voltage source to receive electric energy, and the power supply bus is also connected to the inverter module to supply power to the inverter module, The pre-charging circuit is arranged between the bus capacitor and the power supply bus, and realizes pre-charging of the bus capacitor by electric energy of the voltage source.
2. The pre-charge circuit of claim 1, wherein, The pre-charging circuit comprises a relay and a pre-charging resistor, and the relay and the pre-charging resistor are connected in parallel, The pre-charging resistor is short-circuited or not short-circuited by the on-off state of the relay, and when the pre-charging resistor is not short-circuited, the electric energy of the voltage source pre-charges the bus capacitor through the pre-charging resistor.
3. The pre-charge circuit of claim 2, wherein, The pre-charging circuit further comprises a first diode, and the first diode and the pre-charging resistor are connected in series, The cathode of the first diode is the electrode of the first diode closer to the bus capacitor, and the anode of the first diode is the electrode of the first diode farther away from the bus capacitor.
4. The pre-charge circuit of claim 2, wherein, The inverter further comprises an auxiliary power supply arranged between the inverter module and the power supply bus, The auxiliary power supply is used to supply the inverter module with electric energy on the power supply bus to supply power to the inverter module.
5. The pre-charge circuit of claim 2, wherein, The relay comprises a signal relay.
6. The pre-charge circuit of claim 2, wherein, The pre-charging resistor comprises any one of a metal film resistor, a carbon film resistor, a cement resistor and a thermistor.
7. An inverter, characterized by comprising: The inverter comprises the pre-charging circuit of any one of claims 1 to 6.
8. The inverter of claim 7, wherein, The voltage source comprises a plurality of voltage sources, and the plurality of voltage sources comprise a battery flyback power supply and a grid flyback power supply.
9. The inverter of claim 8, wherein, The inverter further comprises a plurality of second diodes, one second diode is arranged between each voltage source and the power supply bus, the anode of the second diode is the electrode of the second diode closer to the corresponding voltage source, and the cathode of the second diode is the electrode of the second diode farther away from the corresponding voltage source.
10. The inverter of claim 7, wherein, The power supply bus is also used for accessing a photovoltaic output end, and the inverter further comprises a third diode arranged between the photovoltaic output end and the power supply bus, The anode of the third diode is the electrode of the third diode closer to the photovoltaic output end, and the cathode of the third diode is the electrode of the third diode farther away from the photovoltaic output end.