Energy storage inverter and bus capacitor pre-charging circuit thereof

Abstract

The utility model relates to the technical field of energy storage inverters, in particular to an energy storage inverter and a bus capacitor pre-charging circuit thereof. The circuit is used for pre-charging a bus capacitor and comprises a transformer, a primary pre-charging module, a secondary pre-charging module, a first relay module and a second relay module, the transformer comprises a primary side and a first secondary side, the primary side of the transformer is connected with an external mains supply, and the first secondary side is connected with the primary pre-charging module; the first-stage pre-charging module is connected with the bus capacitor and is used for performing first-stage pre-charging on the bus capacitor; the second-stage pre-charging module is connected with the bus capacitor and is used for performing second-stage pre-charging on the bus capacitor after rectifying the external mains supply; the first relay module is arranged between the secondary pre-charging module and an external load, and the second relay module and the first relay module are connected in series and then are connected in series between the secondary pre-charging module and an external mains supply. According to the invention, the overall reliability and stability of the energy storage inverter can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to energy storage inverter technical field, especially a kind of energy storage inverter and bus capacitor pre-charging circuit thereof. BACKGROUND

[0002] Energy storage inverter is an important equipment for energy storage system, which can convert electric energy from DC form to AC form, thereby realizing energy storage and reuse.

[0003] In energy storage inverter, when battery hibernates and there is no photovoltaic input, enter the power supply activation mode, and the power supply charges the bus capacitor through rectifier circuit. At this time, the energy storage inverter is in cold state, and the voltage of the bus capacitor is close to 0 volt. If the path between the power supply and the rectifier circuit is directly connected, the energy storage inverter enters normal work, at this time, the power supply charges the bus capacitor through the rectifier circuit, and the bus capacitor is equivalent to short circuit state, the instantaneous impact current is very large, and the rectifier circuit is easily damaged, and the reliability is poor.

[0004] Therefore, it is necessary to design a simple and high-reliability bus capacitor pre-charging circuit to pre-charge the bus capacitor to improve the overall reliability of the energy storage inverter. UTILITY MODEL CONTENT

[0005] The technical problem to be solved by the embodiments of the utility model is to provide an energy storage inverter and a bus capacitor pre-charging circuit thereof to solve the problem of poor reliability of the energy storage inverter in the prior art.

[0006] The utility model discloses a bus capacitor pre-charging circuit of energy storage inverter for pre-charging bus capacitor, including transformer, first pre-charging module, second pre-charging module, first relay module and second relay module, the transformer includes primary side and first secondary side, wherein,

[0007] The primary side of the transformer is connected with external power supply, and the first secondary side is connected with the first pre-charging module.

[0008] The first pre-charging module is connected with the bus capacitor, and is used for first-stage pre-charging the bus capacitor.

[0009] The second pre-charging module is connected with the bus capacitor, and is used for second-stage pre-charging the bus capacitor after rectifying external power supply.

[0010] The first relay module is arranged between the second pre-charging module and external load, and the second relay module is connected in series with the first relay module and then connected in series between the second pre-charging module and external power supply.

[0011] Optionally, the secondary pre-charging module comprises a first IGBT tube, a second IGBT tube, a third IGBT tube and a fourth IGBT tube, the gate of the first IGBT tube, the gate of the second IGBT tube, the gate of the third IGBT tube and the gate of the fourth IGBT tube are used to receive an external control signal, the emitter of the first IGBT tube is connected to the collector of the second IGBT tube and the connection node thereof is connected to an external load, the collector of the first IGBT tube is connected to the collector of the third IGBT tube and the positive pole of a bus capacitor, the emitter of the second IGBT tube is connected to the emitter of the fourth IGBT tube and the negative pole of the bus capacitor, and the emitter of the third IGBT tube is connected to the collector of the fourth IGBT tube and the connection node thereof is connected to an external power supply and an external load.

[0012] Optionally, the primary pre-charging module comprises a first rectifier diode and a first filter capacitor, the positive pole of the first rectifier diode is connected to a first terminal of the first secondary side, the negative pole of the first rectifier diode is connected to the positive pole of a bus capacitor and the positive pole of the first filter capacitor, and the negative pole of the first filter capacitor is connected to a second terminal of the first secondary side and the negative pole of the bus capacitor.

[0013] Optionally, the primary pre-charging module further comprises an anti-backflow diode, the positive pole of the anti-backflow diode is connected to the negative pole of the first rectifier diode, and the negative pole of the anti-backflow diode is connected to the positive pole of the bus capacitor.

[0014] Optionally, the secondary pre-charging module further comprises an inductor and a second filter capacitor, the inductor is connected in series with the first relay module, the other end of the inductor is connected to the connection node of the emitter of the first IGBT tube and the collector of the second IGBT tube, one end of the second filter capacitor is connected to the series connection node of the inductor and the first relay module, and the other end of the second filter capacitor is connected to the connection node of the emitter of the third IGBT tube and the collector of the fourth IGBT tube.

[0015] Optionally, the first relay module comprises a first relay, the second relay module comprises a second relay, the first relay is connected in series with the second relay, the first relay is arranged between one end of the inductor and an external load, and the second relay is connected in series with the first relay and in series between one end of the inductor and an external power supply.

[0016] Optionally, the transformer further comprises a second secondary side, and the bus capacitor pre-charging circuit further comprises a power supply module, the power supply module comprising a second rectifier diode and a third filter capacitor, a positive electrode of the second rectifier diode being connected to a first terminal of the second secondary side, a negative electrode of the second rectifier diode being connected to a positive electrode of the third filter capacitor and an external main auxiliary power supply, and a negative electrode of the third filter capacitor being connected to a second terminal of the second secondary side and a ground terminal.

[0017] Optionally, the power supply module further comprises a resistor, the resistor being connected in parallel with the third filter capacitor, and the resistor being used for being connected in parallel with an external load.

[0018] Optionally, the bus capacitor pre-charging circuit further comprises a fourth filter capacitor and a switch tube, a positive electrode of the fourth filter capacitor being connected to an external mains and a first terminal of a primary side of the transformer, a negative electrode of the fourth filter capacitor being connected to a source electrode of the switch tube and a ground terminal, a gate electrode of the switch tube being used for receiving an external control signal, and a drain electrode of the switch tube being connected to a second terminal of the primary side of the transformer.

[0019] The utility model discloses still a kind of energy storage inverter, including bus capacitor and the bus capacitor pre-charging circuit of energy storage inverter described above, the first pre-charging module and the second pre-charging module are connected with the bus capacitor, and the bus capacitor is used for being connected in parallel with external battery.

[0020] Compared with prior art, the bus capacitor pre-charging circuit of the energy storage inverter has the beneficial effects that by setting transformer, first pre-charging module, second pre-charging module, first relay module and second relay module, the primary side of transformer is connected to external mains, the first pre-charging module and the second pre-charging module are connected with bus capacitor, the first relay module is arranged between the second pre-charging module and external load, the second relay module is connected in series with the first relay module and connected in series between the second pre-charging module and external mains, before cold start of energy storage inverter, mains can be pre-charged to bus capacitor through first pre-charging module via transformer, after the first relay module and the second relay module are closed, mains can be second pre-charged to bus capacitor through second pre-charging module, after cold start, the first relay module and the second relay module remain closed, and mains can also be rectified by second pre-charging module to supply power to other circuits of energy storage inverter, therefore, by two-stage pre-charging to bus capacitor, there is no large voltage difference before and after cold start of bus capacitor, after cold start, no large impact current is generated to second pre-charging module for mains rectification, and the second pre-charging module for normal operation of energy storage inverter after cold start is shared as second pre-charging of bus capacitor, to realize pre-charging of bus capacitor by relatively simple circuit, and improve reliability and stability of energy storage inverter. BRIEF DESCRIPTION OF DRAWINGS

[0021] The technical scheme of the utility model will be described in further detail below with reference to the drawings and embodiments, wherein:

[0022] Figure 1 is the structure block diagram of the bus capacitor pre-charging circuit of the energy storage inverter provided by the embodiment of the utility model;

[0023] Figure 2 is the circuit principle diagram of the first pre-charging module and the power supply module provided by the embodiment of the utility model;

[0024] Figure 3 is the circuit principle diagram of the second pre-charging module provided by the embodiment of the utility model.

[0025] The various reference signs in the drawings are:

[0026] 110 (T1), transformer; 120, first pre-charging module; 130, second pre-charging module; 140, first relay module; 150, second relay module; 160, power supply module;

[0027] D1, first rectifier diode; D2, anti-backflow diode; D3, second rectifier diode; C1, first filter capacitor; C2, second filter capacitor; C3, third filter capacitor; C4, fourth filter capacitor; C5, bus capacitor; Q1, first IGBT tube; Q2, second IGBT tube; Q3, third IGBT tube; Q4, fourth IGBT tube; L1, inductor; K1, first relay; K2, second relay; R1, resistor; Q5, switch tube. DETAILED DESCRIPTION

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0029] The embodiment of the utility model provides a kind of bus capacitor pre-charging circuit of energy storage inverter, for pre-charging bus capacitor C5.The bus capacitor C5 in energy storage inverter can smooth DC side voltage fluctuation, store energy, and the two ends of bus capacitor C5 are also respectively connected the two ends of battery.When battery hibernates and there is no photovoltaic, energy storage inverter enters commercial power activation working condition, and bus capacitor C5 can be pre-charged by the bus capacitor pre-charging circuit provided in the present application embodiment.

[0030] As Figures 1 to 3As shown, the bus capacitor pre-charging circuit of the energy storage inverter includes a transformer 110 (T1), a first pre-charging module 120, a second pre-charging module 130, a first relay module 140, and a second relay module 150. The transformer 110 (T1) includes a primary side and a first secondary side.

[0031] The primary side of the transformer 110 (T1) is connected to an external power supply, and the first secondary side is connected to the first pre-charging module 120. The primary side of the transformer 110 (T1) obtains electrical energy from the external power supply, converts the voltage, and outputs the converted voltage through the first secondary side.

[0032] The first pre-charging module 120 is connected to the bus capacitor C5 and is used to perform first-stage pre-charging on the bus capacitor C5.

[0033] The second pre-charging module 130 is connected to the bus capacitor C5 and is used to perform second-stage pre-charging on the bus capacitor C5 after rectifying the external power supply.

[0034] The first relay module 140 is arranged between the second pre-charging module 130 and an external load, and the second relay module 150 is connected in series with the first relay module 140 and is then connected in series between the second pre-charging module 130 and the external power supply. The first relay module 140 and the second relay module 150 can achieve electrical isolation between the external power supply and the second pre-charging circuit and between the external power supply and the load.

[0035] The application sets the transformer 110 (T1), the first pre-charging module 120, the second pre-charging module 130, the first relay module 140 and the second relay module 150, the primary side of the transformer 110 (T1) is connected with the external power supply, the first pre-charging module 120 and the second pre-charging module 130 are connected with the bus capacitor C5, the first relay module 140 is arranged between the second pre-charging module 130 and the external load, the second relay module 150 is connected in series with the first relay module 140 and then connected in series between the second pre-charging module 130 and the external power supply, before the cold start of the energy storage inverter, the power supply can pass through the first pre-charging module 120 to perform the first pre-charging on the bus capacitor C5 through the transformer 110 (T1), after the first relay module 140 and the second relay module 150 are closed, the power supply can pass through the second pre-charging module 130 to perform the second pre-charging on the bus capacitor C5, after the cold start, the first relay module 140 and the second relay module 150 remain closed, the power supply can also pass through the second pre-charging module 130 to perform rectification and then supply power to other circuits of the energy storage inverter, therefore, the application performs two-stage pre-charging on the bus capacitor C5, so that there is no large voltage difference before and after the cold start of the bus capacitor C5, after the cold start, the second pre-charging module 130 for rectifying the power supply does not generate a large impact current, and the second pre-charging module 130 for rectifying the power supply is shared as the second pre-charging of the bus capacitor C5 after the normal working of the energy storage inverter, so that the pre-charging of the bus capacitor C5 is realized by a relatively simple circuit, and the reliability and stability of the energy storage inverter are improved.

[0036] The transformer 110 (T1) realizes the voltage conversion and also realizes the electrical isolation between the power supply and the energy storage inverter, so that the overall energy storage inverter meets the safety requirements. After the pre-charging of the bus capacitor C5 is completed, the first relay module 140 and the second relay module 150 remain closed, the external power supply can pass through the second pre-charging module 130 to perform rectification and then supply power to the subsequent load, or the external power supply passes through the second pre-charging module 130 to perform rectification and then charges the battery connected with the bus capacitor C5, that is, the second pre-charging module 130 can perform the second pre-charging on the bus capacitor C5 and also serves as part of the main power loop of the energy storage inverter, without the need to additionally increase the second pre-charging circuit on the basis of the main power loop of the energy storage inverter, the circuit structure is relatively simple, the pre-charging of the bus capacitor C5 also does not need a relatively complex control, the cost is low, and the overall circuit is stable and reliable.

[0037] Reference Figures 1 to 3In the embodiment, the first pre-charging module 120 includes a first rectifier diode D1 and a first filter capacitor C1. The positive electrode of the first rectifier diode D1 is connected to the first terminal of the first secondary side, the negative electrode of the first rectifier diode D1 is connected to the positive electrode of the bus capacitor C5 and the positive electrode of the first filter capacitor C1, and the negative electrode of the first filter capacitor C1 is connected to the second terminal of the first secondary side and the negative electrode of the bus capacitor C5.

[0038] The first rectifier diode D1 is used to convert the alternating current signal output by the first secondary side of the transformer 110 (T1) into a direct current signal. The first filter capacitor C1 is used to filter out stray signals and noise in the circuit, so that the voltage signal in the circuit is more stable.

[0039] The first secondary side of the transformer 110 (T1) can output a suitable alternating current signal. After rectification by the first rectifier diode D1 and filtering by the third filter capacitor C3, a relatively stable suitable voltage is output, which pre-charges the bus capacitor C5 at the first level.

[0040] Further, the first pre-charging module 120 further includes an anti-backflow diode D2, the positive electrode of the anti-backflow diode D2 is connected to the negative electrode of the first rectifier diode D1, and the negative electrode of the anti-backflow diode D2 is connected to the positive electrode of the bus capacitor C5.

[0041] By setting the anti-backflow diode D2, the reverse voltage impact of the bus capacitor C5 can be prevented, avoiding damage to the first rectifier diode D1 and other elements caused by the reverse voltage impact, prolonging the service life of the circuit elements, and improving the stability of the overall circuit operation.

[0042] Reference Figure 1 and Figure 3 In the embodiment, the second pre-charging module 130 includes a first IGBT tube Q1, a second IGBT tube Q2, a third IGBT tube Q3, and a fourth IGBT tube Q4. The gate of the first IGBT tube Q1, the gate of the second IGBT tube Q2, the gate of the third IGBT tube Q3, and the gate of the fourth IGBT tube Q4 are all used to receive an external control signal. The emitter of the first IGBT tube Q1 is connected to the collector of the second IGBT tube Q2, and the connection node thereof is connected to an external load. The collector of the first IGBT tube Q1 is connected to the collector of the third IGBT tube Q3 and the positive electrode of the bus capacitor C5. The emitter of the second IGBT tube Q2 is connected to the emitter of the fourth IGBT tube Q4 and the negative electrode of the bus capacitor C5. The emitter of the third IGBT tube Q3 is connected to the collector of the fourth IGBT tube Q4, and the connection node thereof is connected to an external power supply and an external load.

[0043] An IGBT (Insulated Gate Bipolar Transistor) is a semiconductor device that combines the advantages of bipolar transistors (BJT) and field-effect transistors (FET). An IGBT tube is composed of a PNPN structure, combining the high input impedance of MOSFET and the low on-state voltage drop of BJT. This structure makes the IGBT tube have both the high input impedance and high-speed switching characteristics of MOSFET, and the low on-state voltage drop and large current bearing capacity of BJT, with high efficiency and high-speed switching characteristics. The operation of the IGBT tube is controlled by controlling the gate voltage to control the current flow, and when the voltage applied to the gate exceeds a certain threshold, a conduction channel is formed and the current can flow from the collector to the emitter.

[0044] The first IGBT tube Q1, the second IGBT tube Q2, the third IGBT tube Q3 and the fourth IGBT tube Q4 are connected to form a full-wave uncontrolled rectifier circuit. Before cold start, after the first relay module 140 and the second relay module 150 are closed, the external power supply charges the bus capacitor C5 through the full-wave uncontrolled rectifier circuit, and the voltage of the bus capacitor C5 is the times of the voltage of the power supply. The voltage of the bus capacitor C5 charged by the second-stage pre-charging is not much different from the voltage of the bus capacitor C5 charged by the first-stage pre-charging through the rectification of the first secondary side of the transformer 110 (T1), so the voltage difference between the first-stage pre-charging and the second-stage pre-charging of the bus capacitor C5 is not large, and the full-wave uncontrolled rectifier circuit will not be subjected to a large current impact, and the circuit reliability and stability are high.

[0045] In the full-wave uncontrolled rectifier circuit, by properly controlling the conduction and cutoff of the IGBT tube, the rectification of the input alternating current signal can be realized, and the alternating current signal can be converted into a direct current signal. This rectifier circuit can provide a stable direct current power supply.

[0046] Further, the second-stage pre-charging module 130 further includes an inductor L1 and a second filter capacitor C2. The inductor L1 is connected in series with the first relay module 140, and the other end of the inductor L1 is connected to the connection node of the emitter of the first IGBT tube Q1 and the collector of the second IGBT tube Q2. One end of the second filter capacitor C2 is connected to the series connection node of the inductor L1 and the first relay module 140, and the other end of the second filter capacitor C2 is connected to the connection node of the emitter of the third IGBT tube Q3 and the collector of the fourth IGBT tube Q4.

[0047] The inductor L1 is an electronic component that stores and releases energy in a circuit. The inductor L1 is usually composed of a solenoid or a coil. When current passes through the inductor L1, a magnetic field is generated inside the inductor L1, and energy is stored in the inductor L1 in the form of a magnetic field. Once the current changes, the inductor L1 releases the stored energy. The second filter capacitor C2 can filter out stray signals and noise in the circuit, making the output voltage signal more stable and providing a more stable power supply voltage for the external load.

[0048] In specific operation, by controlling the conduction and cutoff of the first IGBT tube Q1, the second IGBT tube Q2, the third IGBT tube Q3 and the fourth IGBT tube Q4, cooperating with the energy storage and release of the inductor L1 and the filtering effect of the second filter capacitor C2, the mains can supply power to the load through the circuit, the battery can supply power to the load through the circuit, and the mains can also charge the battery through the circuit.

[0049] In this embodiment, referring to Figure 1 and Figure 2 , the first relay module 140 includes a first relay K1, and the second relay module 150 includes a second relay K2. The first relay K1 is connected in series with the second relay K2. The first relay K1 is arranged between one end of the inductor L1 and the external load. The second relay K2 is connected in series with the first relay K1 and then connected in series between one end of the inductor L1 and the external mains.

[0050] The first relay module 140 and the second relay module 150 in this embodiment each include only one relay, which realizes electrical isolation between the external mains and the circuit components of the energy storage inverter, prevents the external mains from interfering with the internal circuit of the energy storage inverter, and meets relevant safety requirements. In other embodiments, the first relay module 140 and the second relay module 150 can each include two or more series-connected relays, which realize electrical isolation between the mains and the circuit components. The circuit structure of the first relay module 140 and the second relay module 150 in this embodiment is simple.

[0051] Referring to Figure 1 and Figure 2 , in this embodiment, the transformer 110 (T1) further includes a second secondary side, and the bus capacitor pre-charging circuit further includes a power supply module 160. The power supply module 160 includes a second rectifier diode D3 and a third filter capacitor C3. The positive electrode of the second rectifier diode D3 is connected to a first connection terminal of the second secondary side. The negative electrode of the second rectifier diode D3 is connected to the positive electrode of the third filter capacitor C3 and an external main auxiliary power supply. The negative electrode of the third filter capacitor C3 is connected to a second connection terminal of the second secondary side and a ground terminal.

[0052] The second rectifier diode D3 is used to convert the AC signal output from the secondary side of the transformer 110 (T1) into a DC signal. The second filter capacitor C2 is used to filter out stray signals and noise in the circuit, making the voltage signal in the circuit more stable.

[0053] The secondary side of the transformer 110 (T1) can output a suitable AC signal, which is rectified by the second rectifier diode D3 and filtered by the third filter capacitor C3 to output a more stable voltage suitable for powering the external main and auxiliary power supply.

[0054] Further, the power supply module 160 also includes a resistor R1, which is connected in parallel with the third filter capacitor C3 and is used to be connected in parallel with the external load. The resistor R1 acts as a load resistor R1 in the circuit, which is used to eliminate the ripple and noise of the DC voltage and stabilize the output current, providing a smooth power supply voltage for the load.

[0055] In this embodiment, referring to Figure 1 and Figure 2 , the bus capacitor pre-charging circuit further includes a fourth filter capacitor C4 and a switch tube Q5. The positive terminal of the fourth filter capacitor C4 is connected to the external power supply and the first terminal of the primary side of the transformer 110 (T1), the negative terminal of the fourth filter capacitor C4 is connected to the source of the switch tube Q5 and the ground terminal, the gate of the switch tube Q5 is used to receive an external control signal, and the drain is connected to the second terminal of the primary side of the transformer 110 (T1).

[0056] The switch tube Q5 is an electronic device used to control the flow of current. The switch tube Q5 can be in one of two states: an on state and an off state. In the on state, the switch tube Q5 allows current to flow, while in the off state, the switch tube Q5 blocks the flow of current. The working principle of the switch tube Q5 is based on the voltage signal of the gate. When the gate applies an appropriate voltage, the switch tube Q5 can be switched to the on state, allowing current to pass through; when the voltage of the gate is insufficient or inappropriate, the switch tube Q5 is in the off state, and the current cannot pass through.

[0057] By controlling the on and off of the switch tube Q5, the size of the output voltage can be adjusted. The switching action of the switch tube Q5 periodically transfers energy to the output end, achieving the adjustment of the output voltage. Specifically, when the switch tube Q5 is on, the external power supply enters the transformer 110 (T1) through the switch tube Q5, and the energy is stored in the transformer 110 (T1); when the switch tube Q5 is off, the energy in the transformer 110 (T1) is transferred to the output end, i.e. the secondary side of the transformer 110 (T1) through the flyback action.

[0058] In the embodiment of the application, the switch tube Q5 specifically adopts an NMOS tube, the gate of the NMOS tube receives an external control signal, the source is connected to the negative pole of the fourth filter capacitor C4 and the ground terminal, and the drain is connected to the second connection terminal of the primary side of the transformer 110 (T1).

[0059] The fourth filter capacitor C4 is used for smoothing the output voltage. Since the switching action of the switch tube Q5 will introduce pulsation, the fourth filter capacitor C4 can smooth the pulsation and reduce the ripple of the output voltage, so that the output voltage is more stable.

[0060] The application also provides a storage energy inverter, which comprises a bus capacitor C5 and the bus capacitor pre-charging circuit of the storage energy inverter as described above, the first pre-charging module 120 and the second pre-charging module 130 are connected to the bus capacitor C5, and the bus capacitor C5 is used for being connected in parallel with an external battery.

[0061] In the embodiment of the application, the bus capacitor pre-charging circuit of the storage energy inverter is provided with the transformer 110 (T1), the first pre-charging module 120, the second pre-charging module 130, the first relay module 140 and the second relay module 150, the primary side of the transformer 110 (T1) is connected to external power, the first pre-charging module 120 and the second pre-charging module 130 are connected to the bus capacitor C5, the first relay module 140 is arranged between the second pre-charging module 130 and an external load, and the second relay module 150 is connected in series with the first relay module 140 and then connected in series between the second pre-charging module 130 and the external power. Before cold start of the storage energy inverter, the power can pass through the first pre-charging module 120 to perform first-stage pre-charging on the bus capacitor C5 through the transformer 110 (T1). After the first relay module 140 and the second relay module 150 are closed, the power can pass through the second pre-charging module 130 to perform second-stage pre-charging on the bus capacitor C5. After cold start, the first relay module 140 and the second relay module 150 remain closed, and the power can also pass through the second pre-charging module 130 to rectify and supply power to other circuits of the storage energy inverter. Therefore, the application pre-charges the bus capacitor C5 in two stages, so that there is no large voltage difference before and after cold start of the bus capacitor C5, and no large impact current is generated on the second pre-charging module 130 for rectifying the power after cold start of the storage energy inverter, and the second pre-charging module 130 for normal work after cold start of the storage energy inverter is shared as the second-stage pre-charging of the bus capacitor C5. The pre-charging of the bus capacitor C5 is realized by a relatively simple circuit, and the reliability and stability of the storage energy inverter are improved.

[0062] The storage energy inverter comprises the same circuit structure and beneficial effects as the bus capacitor pre-charging circuit in the foregoing embodiment, and the other structures and beneficial effects of the bus capacitor pre-charging circuit have been described in detail in the foregoing embodiment, which will not be described herein.

[0063] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, but not limit them, and for those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced equivalently; all these modifications and replacements should belong to the protection scope of the claims of the present application.

Claims

1. A bus capacitor pre-charging circuit for an energy storage inverter, used for pre-charging the bus capacitor, characterized in that, The system includes a transformer, a primary pre-charge module, a secondary pre-charge module, a first relay module, and a second relay module. The transformer includes a primary side and a first secondary side. The primary side of the transformer is connected to the external mains power, and the first secondary side is connected to the first-stage precharge module; The first-stage pre-charge module is connected to the bus capacitor and is used to perform the first-stage pre-charge of the bus capacitor. The secondary pre-charge module is connected to the bus capacitor and is used to perform a second-stage pre-charge on the bus capacitor after rectifying the external mains power. The first relay module is located between the secondary precharge module and the external load, and the second relay module is connected in series with the first relay module and then connected in series between the secondary precharge module and the external mains power.

2. The bus capacitor pre-charging circuit according to claim 1, characterized in that, The secondary precharge module includes a first IGBT, a second IGBT, a third IGBT, and a fourth IGBT. The gates of the first, second, third, and fourth IGBTs are all used to receive external control signals. The emitter of the first IGBT is connected to the collector of the second IGBT, and its connection node is connected to an external load. The collector of the first IGBT is connected to the collector of the third IGBT and the positive terminal of the bus capacitor. The emitter of the second IGBT is connected to the emitter of the fourth IGBT and the negative terminal of the bus capacitor. The emitter of the third IGBT is connected to the collector of the fourth IGBT, and its connection node is connected to the external AC power and the external load.

3. The bus capacitor pre-charging circuit according to claim 2, characterized in that, The first-level precharge module includes a first rectifier diode and a first filter capacitor. The positive terminal of the first rectifier diode is connected to the first terminal of the first secondary side, the negative terminal of the first rectifier diode is connected to the positive terminal of the bus capacitor and the positive terminal of the first filter capacitor, and the negative terminal of the first filter capacitor is connected to the second terminal of the first secondary side and the negative terminal of the bus capacitor.

4. The bus capacitor pre-charging circuit according to claim 3, characterized in that, The primary precharge module also includes an anti-reverse current diode, the positive terminal of which is connected to the negative terminal of the first rectifier diode, and the negative terminal of which is connected to the positive terminal of the bus capacitor.

5. The bus capacitor pre-charging circuit according to claim 4, characterized in that, The secondary precharge module further includes an inductor and a second filter capacitor. The inductor is connected in series with the first relay module. The other end of the inductor is connected to the connection node between the emitter of the first IGBT and the collector of the second IGBT. One end of the second filter capacitor is connected to the connection node between the inductor and the first relay module, and the other end of the second filter capacitor is connected to the connection node between the emitter of the third IGBT and the collector of the fourth IGBT.

6. The bus capacitor pre-charging circuit according to claim 5, characterized in that, The first relay module includes a first relay, and the second relay module includes a second relay. The first relay and the second relay are connected in series. The first relay is disposed between one end of the inductor and an external load, and the second relay is connected in series with the first relay and then connected in series between one end of the inductor and an external mains power supply.

7. The bus capacitor pre-charging circuit according to any one of claims 1-6, characterized in that, The transformer also includes a second secondary side, and the bus capacitor pre-charging circuit also includes a power supply module. The power supply module includes a second rectifier diode and a third filter capacitor. The positive terminal of the second rectifier diode is connected to the first terminal of the second secondary side, and the negative terminal of the second rectifier diode is connected to the positive terminal of the third filter capacitor and the external main and auxiliary power supply. The negative terminal of the third filter capacitor is connected to the second terminal of the second secondary side and the ground terminal.

8. The bus capacitor pre-charging circuit according to claim 7, characterized in that, The power supply module also includes a resistor connected in parallel with the third filter capacitor, and the resistor is used to connect in parallel with an external load.

9. The bus capacitor pre-charging circuit according to any one of claims 1-6, characterized in that, The bus capacitor pre-charging circuit also includes a fourth filter capacitor and a switching transistor. The positive terminal of the fourth filter capacitor is connected to the external mains power and the first terminal of the primary side of the transformer. The negative terminal of the fourth filter capacitor is connected to the source and ground of the switching transistor. The gate of the switching transistor is used to receive external control signals, and the drain is connected to the second terminal of the primary side of the transformer.

10. An energy storage inverter, characterized in that, It includes a bus capacitor and a bus capacitor pre-charging circuit for an energy storage inverter as described in any one of claims 1-9, wherein both the primary pre-charging module and the secondary pre-charging module are connected to the bus capacitor, and the bus capacitor is used to be connected in parallel with an external battery.

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