High-power bidirectional two-way direct current input switching device

Abstract

The utility model discloses a high-power bidirectional two-way direct-current input switching device, which relates to the technical field of power supply control, and comprises a controller, an inverter circuit, a voltage sampling assembly, a driving circuit and two direct-current input branches with the same structure, and the two direct-current input branches are arranged in parallel between a direct-current input end and the inverter circuit. The direct current input branch comprises a slow start assembly, a forward conduction assembly and a reverse conduction assembly, and forward conduction and reverse conduction of the branch can be realized; according to the technical scheme, when one of the preceding-stage double-path direct-current power supply branches breaks down, the other branch is adopted for power supply, it is guaranteed that the high-power power conversion device works continuously, the device can achieve the slow-start power-on function through the slow-start assembly, and the reliability of the device is improved. And the voltage rise of the direct current bus can be inhibited through the reverse conduction assembly and the direct current connection assembly between the power supplies, so that the working reliability of the direct current input high-power power conversion device is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply control, in particular to a high-power bidirectional dual-path DC input switching device. Background Art

[0002] In the field of power control technology, inverters are typically used to convert input DC power into output AC power to meet the power demands of AC loads. This process typically utilizes dual DC inputs to improve the inverter's power supply reliability. This means that if one input fails, the inverter can seamlessly switch to the other input, ensuring the inverter's DC input supply and maintaining continuous output power. Furthermore, dual DC inputs enable energy scheduling from different DC sources, allowing for the targeted selection of a primary power supply branch based on the grid system's energy scheduling needs.

[0003] Existing technologies or products rely on uncontrolled devices such as diodes to achieve DC input switching of inverter power supplies, which has the following shortcomings: (1) When switching DC input, only the input branch with a high voltage value can be selected. When the voltage of the main branch is slightly lower but still within the normal voltage range, it is impossible to give priority to the main branch; (2) There is no reverse channel for switching. Due to reasons such as multiple machines in parallel, grid-connected operation, and motor pumping, the inverter power supply may have reverse input power on the AC side, causing DC bus overvoltage. If there are no energy consumption or discharge measures, it may cause DC overvoltage protection shutdown. Utility Model Content

[0004] The purpose of the utility model is to provide a device with a dual-path input structure and capable of achieving bidirectional power flow in each path, in order to address the problems in the prior art of dual-path DC input inverter power supplies, such as the lack of a reverse channel when switching and the inability to give priority to the use of the main branch during the power conversion process.

[0005] The technical solution of the utility model is: providing a high-power bidirectional dual-path DC input switching device, which includes an inverter circuit and two DC input branches with the same structure;

[0006] The input ends of the two DC input branches are respectively connected to the DC power supply through the DC switch, and the output ends of the two DC input branches are respectively connected to the inverter circuit through the DC bus. The DC power supply is used to supply power to the inverter circuit through any DC input branch;

[0007] The DC input branch includes a slow-start component, a fast forward conducting positive component, a fast reverse conducting positive component, a fast forward conducting negative component and a fast reverse conducting negative component, wherein the slow-start component, the fast forward conducting positive component and the fast reverse conducting positive component are arranged in parallel between the positive pole of the input terminal of the DC input branch and the positive pole of the DC bus, and the fast forward conducting negative component and the fast reverse conducting negative component are arranged in parallel between the negative pole of the input terminal of the DC input branch and the negative pole of the DC bus;

[0008] The slow-start component is used to limit the DC input current to a safe value when the main power is first applied;

[0009] The fast forward conducting positive electrode component and the fast forward conducting negative electrode component are used to conduct forward conduction on the DC input branch, so that the DC power supply supplies power to the inverter circuit;

[0010] The fast reverse conducting positive electrode component and the fast reverse conducting negative electrode component are used to reverse conduct the DC input branch, so that the inverter circuit feeds the active current back to the input end of the DC input branch;

[0011] The inverter circuit is used to convert the input DC power into AC power for output.

[0012] Furthermore, the input end of the slow-start component is connected to the positive input end of the DC input branch, and the output end of the slow-start component is connected to the positive DC bus;

[0013] The slow-start component is composed of a diode and a resistor connected in series, wherein the resistor is used to slow down the rate of current rise, and the diode is used to limit the current to conduct forward.

[0014] Furthermore, the input end of the fast forward conducting positive electrode assembly is connected to the positive input end of the DC input branch, and the output end of the fast forward conducting positive electrode assembly is connected to the positive electrode of the DC bus;

[0015] The fast forward conducting positive electrode component is composed of a thyristor rectifier, a capacitor, a resistor and a diode. The resistor and the diode are connected in parallel, and the whole formed in parallel is connected in series with the capacitor. The whole formed by the capacitor, the resistor and the diode is connected in parallel with the thyristor rectifier. The thyristor rectifier is used to control the on and off of the fast forward conducting positive electrode component. The capacitor is used to smooth the voltage changes of the fast forward conducting positive electrode component through the charging and discharging process. The resistor is used to prevent excessive current from passing through and causing damage to the components. The diode is used to prevent current from flowing in the fast forward conducting positive electrode component.

[0016] Furthermore, the direction of the thyristor rectifier anode is the input end of the fast forward conducting positive electrode component, the direction of the thyristor rectifier cathode is the output end of the fast forward conducting positive electrode component, and the control electrode of the thyristor rectifier anode is connected to the drive circuit.

[0017] Furthermore, the input end of the fast reverse conducting positive electrode component is connected to the positive electrode of the DC bus, and the output end of the fast reverse conducting positive electrode component is connected to the positive electrode of the input end of the DC input branch;

[0018] The composition structure of the fast reverse conducting positive electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conducting direction of the fast reverse conducting positive electrode assembly is opposite to that of the fast forward conducting positive electrode assembly.

[0019] Furthermore, the input end of the fast forward conducting negative electrode component is connected to the negative input end of the DC input branch, and the output end of the fast forward conducting negative electrode component is connected to the negative electrode of the DC bus;

[0020] The composition structure of the fast forward conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conduction direction of the fast forward conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly.

[0021] Furthermore, the input end of the fast reverse conducting negative electrode component is connected to the positive pole of the DC bus, and the output end of the fast reverse conducting negative electrode component is connected to the positive pole of the input end of the DC input branch;

[0022] The composition structure of the fast reverse conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conducting direction of the fast reverse conducting negative electrode assembly is opposite to that of the fast forward conducting positive electrode assembly.

[0023] Furthermore, the high-power bidirectional dual-channel DC input switching device also includes a voltage sampling component, which is respectively arranged on the DC input branch input end and the DC bus, and is used to measure the voltage of the DC input branch input end and the DC bus.

[0024] Furthermore, the high-power bidirectional dual-path DC input switching device further includes a drive circuit and a controller;

[0025] The driving circuit is used to control the on and off of the fast forward conducting positive electrode component, the fast reverse conducting positive electrode component, the fast forward conducting negative electrode component and the fast reverse conducting negative electrode component through a trigger signal;

[0026] The controller is used to control the drive circuit to send trigger signals to various components according to the voltage values ​​of the DC input branch input terminal and the DC bus.

[0027] The beneficial effects of the utility model are:

[0028] First, the technical solution in the present application sets up two DC input branches with the same structural composition in the inverter power supply, and uses controllable electronic switching devices to build a fast forward conduction component in the DC input branch. The forward conduction component can realize controllable and fast switching of the two DC input branches, and can ensure that the input branch is reasonably selected according to the requirements of energy scheduling, priority of specific branches, etc. during the power supply process; the technical solution in the present application can realize fast branch switching in the case of abnormal DC input, reduce DC bus voltage drop, and increase power supply stability. Compared with the inverter power supply in the prior art, the technical solution in the present application can switch to the backup branch when an abnormal DC input problem occurs in the main branch, avoid the frequent switching problem caused by the imbalance of voltage between the branches in the circuit, and improve the stability of the inverter power supply.

[0029] Second, the technical solution in the present application also uses controllable electronic switching devices to build a fast reverse discharge component in the DC input branch. The reverse discharge component can perform energy feedback when reverse power occurs on the AC side of the inverter power supply, effectively suppressing the DC bus voltage overvoltage and ensuring the stable operation of the inverter power supply under reverse power conditions. The fast reverse discharge component can solve the problem of abnormal increase in DC bus voltage when the inverter power supply is connected in parallel with multiple machines, directly in parallel with the shore power grid, or with back electromotive force loads. Compared with the switching mode without reverse channel in the existing technology, the discharge measures of the technical solution in the present application can avoid the protection shutdown problem caused by DC overvoltage.

[0030] Third, the technical solution in this application also sets a DC bus tie switch on the DC bus of multiple inverter power supplies, which can effectively suppress DC bus voltage overvoltage by feeding back active current to the DC input terminals of all parallel inverter power supplies. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The advantages of the above and / or additional aspects of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 This is a functional schematic diagram of a high-power bidirectional dual-path DC input automatic switching device according to an embodiment of the present application;

[0033] Figure 2 This is a circuit diagram of an embodiment of a high-power bidirectional dual-path DC input automatic switching device according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0036] like Figures 1 to 2 As shown, this embodiment provides a high-power bidirectional dual-path DC input switching device, which includes: a first DC input branch, a second DC input branch, a voltage sampling component, a drive circuit, a controller and an inverter circuit.

[0037] In this embodiment, the first DC input branch and the second DC input branch are two DC input branches with the same structure. The DC input branch includes a slow-start component, a fast forward conducting positive electrode component, a fast reverse conducting positive electrode component, a fast forward conducting negative electrode component and a fast reverse conducting negative electrode component. The first DC input branch and the second DC input branch are respectively introduced in detail below.

[0038] The input end of the first DC input branch is connected to the external DC power supply through a DC switch, and the output end is connected to the inverter circuit through a DC bus; specifically, a first DC input positive pole V1P and a first DC input negative pole V1N are set on the side of the first DC input branch connected to the DC power supply, the first DC input positive pole V1P is used to connect to the positive pole of the external DC power supply through the DC switch, and the first DC input negative pole V1N is used to connect to the negative pole of the external DC power supply through the DC switch, the positive and negative poles of the side of the first DC input branch connected to the inverter circuit are respectively connected to the DC bus positive pole VbusP and the DC bus negative pole VbusN, and the DC bus positive pole VbusP and the DC bus negative pole VbusN are respectively connected to the inverter circuit.

[0039] The first DC input branch includes a first slow-start component P10, a first fast forward conducting positive component P11, a first fast reverse conducting positive component P12, a first fast forward conducting negative component N11 and a first fast reverse conducting negative component N12; wherein, the first slow-start component P10, the first fast forward conducting positive component P11 and the first fast reverse conducting positive component P12 are arranged in parallel between the first DC input positive pole V1P and the DC bus positive pole VbusP, and the first fast forward conducting negative component N11 and the first fast reverse conducting negative component N12 are arranged in parallel between the first DC input negative pole V1N and the DC bus negative pole VbusN.

[0040] The first ramp-up component P10 is used to limit the DC input current to a safe value during initial power-up until the DC bus voltage reaches the preset DC input voltage. Its input is connected to the first DC input positive terminal V1P, and its output is connected to the DC bus positive terminal VbusP. The first ramp-up component P10 consists of a diode D10 and a resistor R10 connected in series. Resistor R10 slows the current rise rate, while D10 limits the current to forward conduction.

[0041] Specifically, such as Figure 2 As shown, when the DC input voltage is applied to the first slow-start component P10, the resistor R10 limits the increase of instantaneous current to prevent excessive current from impacting the circuit. After the resistor limits the current, the voltage of the DC bus will gradually rise and gradually approach the preset DC input voltage. This process effectively realizes the slow start and avoids the instantaneous large current caused by directly applying high voltage. D10 ensures that the current is only conducted in the forward direction to prevent the influence of reverse current and further protect the circuit.

[0042] In this embodiment, a slow-start component is used to control the rising speed of the voltage and current in the DC bus to avoid current surges or voltage mutations in the circuit at the moment of power-on, achieve smooth startup of the power input, and avoid damage to sensitive components in the circuit.

[0043] The first fast forward conducting positive electrode component P11 is used to conduct forward conduction (forward conduction refers to the conduction state when the DC power supply supplies power to the inverter circuit) under the triggering of the driving circuit, so that the DC power supply supplies power to the inverter circuit. The input end of the first fast forward conducting positive electrode component P11 is connected to the first DC input positive electrode V1P, and the output end is connected to the DC bus positive electrode VbusP; the first fast forward conducting positive electrode component P11 consists of a silicon controlled rectifier SCR11 (Silicon A Controlled Rectifier (a semiconductor device with three terminals, whose conduction requires a trigger signal to be applied to the control electrode G), consists of a capacitor C11, a resistor R11, and a diode D11. The resistor R11 and the diode D11 are connected in parallel, and the entire combination of the resistor R11 and the diode D11 is connected in series with the capacitor C11. The entire combination of the capacitor C11, the resistor R11, and the diode D11 is connected in parallel with the thyristor rectifier SCR11. The thyristor rectifier SCR11 is used to control the on and off of the first fast forward conducting positive electrode component P11 according to the trigger signal sent by the drive circuit. The capacitor C11 is used to smooth the voltage changes of the first fast forward conducting positive electrode component P11 through the charging and discharging process to prevent instantaneous current surges. The resistor R11 is used to limit the amount of current passing through to prevent excessive current from damaging other components. The diode D11 is used to prevent reverse current flow in the first fast forward conducting positive electrode component P11. The anode of the silicon-controlled rectifier SCR11 is directed toward the input of the first fast-forward-conducting positive electrode component P11, and the cathode of the silicon-controlled rectifier SCR11 is directed toward the output of the first fast-forward-conducting positive electrode component P11. The silicon-controlled rectifier SCR11 conducts from the positive electrode of the DC input branch to the positive electrode of the DC bus. Its control electrode G is connected to the drive circuit, and the diode D11 conducts from the positive electrode of the DC input branch to the positive electrode of the DC bus.

[0044] Specifically, such as Figure 2 As shown, when the driving circuit does not send a trigger signal, SCR11 is in the off state, no current flows through the branch where it is located, and capacitor C11 enters the charging state to limit the current passing through capacitor C11. R11 prevents the capacitor from charging too quickly or excessive current from occurring when SCR11 is not turned on. After the driving circuit sends a trigger signal to the control electrode G of SCR11, SCR11 is turned on, and current flows through the branch where it is located. Capacitor C11 discharges quickly when SCR11 is triggered and provides instantaneous energy to SCR11, helping the circuit to quickly establish current at the moment of turn-on. After discharging, capacitor C11 enters the charging state again. During the whole process, D11 prevents reverse current to ensure that the current flows in the expected direction when SCR11 is triggered.

[0045] The first fast reverse conducting positive electrode component P12 is used to reverse conduct when triggered by the driving circuit (reverse conduction refers to the conduction state in which the inverter circuit feeds back the active current to the DC input end of the current inverter power supply), so that the inverter circuit feeds back the active current to the input end of the DC input branch. The input end of the first fast reverse conducting positive electrode component P12 is connected to the DC bus positive electrode VbusP, and the output end is connected to the first DC input positive electrode V1P; the first fast reverse conducting positive electrode component P12 is composed of a thyristor rectifier SCR12, a capacitor C12, a resistor R12 and a diode D12. The structure and working principle of the first fast reverse conducting positive electrode component P12 are the same as those of the first fast forward conducting positive electrode component P11. The conduction direction of the first fast reverse conducting positive electrode component P12 is opposite to that of the first fast forward conducting positive electrode component P11. The conduction direction of the thyristor rectifier SCR12 is from the DC bus positive electrode to the DC input branch positive electrode, and its control electrode G is connected to the drive circuit. The conduction direction of the diode D12 is from the DC bus positive electrode to the DC input branch positive electrode. No further details are given here.

[0046] The first fast forward conducting negative electrode component N11 is used to conduct forward conduction when triggered by the drive circuit, so that the DC power supply supplies power to the inverter circuit. The input end of the first fast forward conducting negative electrode component N11 is connected to the first DC input negative electrode V1N, and the output end is connected to the DC bus negative electrode VbusN. The first fast forward conducting negative electrode component N11 is composed of a thyristor rectifier SCR13, a capacitor C13, a resistor R13 and a diode D13. The resistor R13 and the diode D13 are connected in parallel, and the whole composed of the resistor R13 and the diode D13 is connected in series with the capacitor C13. The whole composed of the capacitor C13, the resistor R13 and the diode D13 is connected to the thyristor. Rectifier SCR13 is connected in parallel. The silicon-controlled rectifier SCR13 is used to control the on and off of the first fast forward conducting negative electrode component N11 according to the trigger signal sent by the drive circuit. Capacitor C13 is used to smooth the voltage changes of the first fast forward conducting negative electrode component N11 through the charging and discharging process to prevent instantaneous current surges. Resistor R13 is used to limit the amount of current passing through to prevent excessive current from damaging other components. Diode D13 is used to prevent current from flowing backward in the first fast forward conducting positive electrode component P11. The structure and operating principle of the first fast forward conducting negative electrode component N11 are similar to those of the first fast forward conducting positive electrode component P11. The conduction direction of the silicon-controlled rectifier SCR13 is from the negative electrode of the DC input branch to the negative electrode of the DC bus. Its control electrode G is connected to the drive circuit. The conduction direction of the diode D13 is from the negative electrode of the DC input branch to the negative electrode of the DC bus. These details will not be repeated here.

[0047] The first fast reverse conducting cathode component N12 is used to conduct reverse conduction under the triggering of the driving circuit, so that the inverter circuit feeds back the active current to the input end of the DC input branch. The input end of the first fast reverse conducting negative electrode component N12 is connected to the negative electrode VbusN of the DC bus, and the output end is connected to the first DC input negative electrode V1N; the first fast reverse conducting negative electrode component N12 is composed of a thyristor rectifier SCR14, a capacitor C14, a resistor R14 and a diode D14. The structure and working principle of the first fast reverse conducting negative electrode component N12 are the same as those of the first fast forward conducting negative electrode component N11. The conduction direction of the first fast reverse conducting negative electrode component N12 is opposite to that of the first fast forward conducting negative electrode component N11, wherein the conduction direction of the thyristor rectifier SCR14 is from the negative electrode of the DC bus to the negative electrode of the DC input branch, its control electrode G is connected to the drive circuit, and the conduction direction of the diode D14 is from the negative electrode of the DC bus to the negative electrode of the DC input branch. No further details will be given here.

[0048] One side of the second DC input branch is connected to the external DC power supply through a DC switch, and the other side is connected to the inverter circuit through a DC bus; specifically, a second DC input positive pole V2P and a second DC input negative pole V2N are set on the side of the second DC input branch connected to the DC power supply, the second DC input positive pole V2P is used to connect to the positive pole of the external DC power supply through the DC switch, and the second DC input negative pole V2N is used to connect to the negative pole of the external DC power supply through the DC switch, the positive and negative poles of the side of the second DC input branch connected to the inverter circuit are respectively connected to the DC bus positive pole VbusP and the DC bus negative pole VbusN, and the DC bus positive pole VbusP and the DC bus negative pole VbusN are respectively connected to the inverter circuit.

[0049] The first DC input branch and the second DC input branch are arranged in parallel in the inverter power supply. When in use, one of them is selected to be opened for power transmission. When one of the branches fails, it can be instantly switched to the other branch. For example, when the first DC input branch is opened, the first DC input positive electrode V1P and the first DC input negative electrode V1N are connected to the DC power supply through the DC switch, and the current of the DC power supply is supplied to the inverter current through the first DC input branch.

[0050] The second DC input branch includes a second slow-start component P20, a second fast forward conducting positive component P21, a second fast reverse conducting positive component P22, a second fast forward conducting negative component N21 and a second fast reverse conducting negative component N22; wherein, the second slow-start component P20, the second fast forward conducting positive component P21 and the second fast reverse conducting positive component P22 are arranged in parallel between the second DC input positive pole V2P and the DC bus positive pole VbusP, and the second fast forward conducting negative component N21 and the second fast reverse conducting negative component N22 are arranged in parallel between the second DC input negative pole V2N and the DC bus negative pole VbusN.

[0051] The input end of the second slow-start component P20 is connected to the second DC input positive electrode V2P, and the output end is connected to the DC bus positive electrode VbusP; the second slow-start component P20 is composed of a diode D20 and a resistor R20 connected in series.

[0052] The input end of the second fast forward conducting positive electrode component P21 is connected to the second DC input positive electrode V2P, and the output end is connected to the DC bus positive electrode VbusP; the second fast forward conducting positive electrode component P21 is composed of a thyristor rectifier SCR21, a capacitor C21, a resistor R21 and a diode D21. The connection method of the various components inside the second fast forward conducting positive electrode component P21 is the same as the connection method of the various components inside the first fast forward conducting positive electrode component P11.

[0053] The input end of the second fast reverse conducting positive electrode assembly P22 is connected to the DC bus positive electrode VbusP, and the output end is connected to the second DC input positive electrode V2P. The second fast reverse conducting positive electrode assembly P22 is composed of a silicon controlled rectifier SCR22, a capacitor C22, a resistor R22, and a diode D22. The connection method of the components within the second fast reverse conducting positive electrode assembly P22 is the same as the connection method of the components within the first fast reverse conducting positive electrode assembly P12. The second fast forward conducting positive electrode assembly P21 and the second fast reverse conducting positive electrode assembly P22 have opposite conduction directions.

[0054] The input end of the second fast forward conducting negative electrode component N21 is connected to the second DC input negative electrode V2N, and the output end is connected to the DC bus negative electrode VbusN; the second fast forward conducting negative electrode component N21 is composed of a thyristor rectifier SCR23, a capacitor C23, a resistor R23 and a diode D23. The connection method of the various components inside the second fast forward conducting negative electrode component N21 is the same as the connection method of the various components inside the first fast forward conducting negative electrode component N11.

[0055] The input end of the second fast reverse conducting cathode assembly N22 is connected to the negative DC bus VbusN, and the output end is connected to the second DC input negative electrode V2N. The second fast reverse conducting cathode assembly N22 is composed of a silicon controlled rectifier SCR24, a capacitor C24, a resistor R24, and a diode D24. The connection method of the components within the second fast reverse conducting cathode assembly N22 is the same as the connection method of the components within the first fast reverse conducting cathode assembly N12. The second fast forward conducting cathode assembly N21 and the second fast reverse conducting cathode assembly N22 have opposite conduction directions.

[0056] The connection mode and working principle of each component structure in the second DC input branch are the same as those of the first DC input branch, and will not be repeated here.

[0057] The voltage sampling component is used to measure the voltage in the branch, including a first voltage sampling V1, a second voltage sampling V2 and a bus voltage sampling V3. The first voltage sampling V1 is set between the first DC input positive pole V1P and the first DC input negative pole V1N, the second voltage sampling V2 is set between the second DC input positive pole V2P and the second DC input negative pole V2N, and the bus voltage sampling V3 is set between the DC bus positive pole VbusP and the DC bus negative pole VbusN.

[0058] The driving circuit is respectively connected to the terminals for receiving trigger signals of the first fast forward conducting positive component P11, the first fast reverse conducting positive component P12, the first fast forward conducting negative component N11, the first fast reverse conducting negative component N12, the second fast forward conducting positive component P21, the second fast reverse conducting positive component P22, the second fast forward conducting negative component N21, and the second fast reverse conducting negative component N22, and is used to control the on and off of each component by sending a trigger signal. Specifically, the driving circuit is connected to the control electrode G of the thyristor rectifier (that is, the terminal for receiving the trigger signal).

[0059] The controller is connected to the first voltage sampling V1, the second voltage sampling V2, the bus voltage sampling V3 and the driving circuit respectively, and is used to obtain the voltage value of each sampling position and control the driving circuit to send a trigger signal to each component according to the voltage value of each sampling position.

[0060] The inverter circuit is set inside the inverter power supply and is used to convert the input direct current into alternating current for output.

[0061] The high-power bidirectional dual-channel DC input automatic switching device also includes a bus tie switch SD0, which is set between two adjacent power supplies and is used to connect different DC power supplies to achieve load distribution between different power supplies and improve the reliability and flexibility of the power supply system.

[0062] Specifically, the positive and negative poles of adjacent DC power supplies are connected via bus tie switches SD0; Figure 1 As shown, inverter power supply A and inverter power supply B are connected in parallel, DC power supply VDC1 supplies power to inverter power supply A, and DC power supply VDC2 supplies power to inverter power supply B. A bus tie switch SD0 is provided between DC power supply VDC1 and DC power supply VDC2. The positive electrode of DC power supply VDC1 is connected to the positive electrode of DC power supply VDC2 through the bus tie switch SD0, and the negative electrode of DC power supply VDC1 is connected to the negative electrode of DC power supply VDC2 through the bus tie switch SD0.

[0063] The working principle of the high-power bidirectional dual-channel DC input switching device in this embodiment is as follows:

[0064] The first DC input branch in the inverter power supply is used as the main branch, the second DC input branch is used as the standby branch, and the DC switch SD1 between the external DC power supply VDC1 and the inverter power supply input terminal is closed.

[0065] The DC current output by the DC power supply VDC1 is passed into the inverter power supply. The DC input current reaches the DC bus through the slow-start components P10 and P20 in the two DC input branches. The voltage of the DC bus gradually increases under the action of the DC input current. The slow-start component limits the DC input current to a preset safety value through an internally set resistor. The voltage sampling component measures the voltage between the positive and negative poles of the DC bus. After the voltage of the DC bus reaches a predetermined range, the controller sends a trigger signal to the first fast forward conducting positive component P11 and the first fast forward conducting negative component N11 through the drive circuit. P11 and N11 are turned on, causing the entire main branch to be forward-conducted. The DC power supply VDC1 supplies power to the inverter circuit through the main branch. The inverter circuit converts the DC input current into AC current and outputs the AC current.

[0066] When the DC bus voltage is too high, the main branch is reversed, and the controller sends a trigger signal to the first fast reverse conducting positive component P12 and the first fast reverse conducting negative component N12 through the drive circuit. P12 and N12 are turned on, so that the entire main branch is reversed, and the active current is fed back to the DC input terminal of the current inverter power supply. If the DC bus voltage returns to normal, the controller sends a trigger signal to P11 and N11 through the drive circuit, P11 and N11 are turned on, and P12 and N12 are turned off at the same time. If the DC bus voltage is still too high after the main branch is reversed, the controller sends a signal to the DC bus coupling switch SD0 to turn on SD0, and feed back the active current to the DC input terminals of all parallel inverter power supplies, so that the DC bus voltage drops to a range that does not exceed the overvoltage limit.

[0067] When the main branch fails, the backup branch is switched to supply power. The controller sends a trigger signal to the second fast forward conducting positive electrode component P21 and the second fast forward conducting negative electrode component N21 through the drive circuit. P21 and N21 are turned on, and the DC power supply VDC1 supplies power to the inverter circuit through the backup branch.

[0068] In this utility model, the terms "install," "connect," "connect," and "fix" should be understood in a broad sense. For example, "connect" can refer to a fixed connection, a detachable connection, or an integral connection; "connected" can refer to a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0069] The shapes of the various components in the drawings are schematic, and certain differences from their actual shapes are not excluded. The drawings are only used to illustrate the principles of the present invention and are not intended to limit the present invention.

[0070] Although the present invention is disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and are not intended to limit the application of the present invention. The scope of protection of the present invention is defined by the appended claims and includes various modifications, variations, and equivalents made to the present invention without departing from the scope and spirit of the present invention.

Claims

1. A high-power bidirectional dual-path DC input switching device, characterized in that: The device comprises: an inverter circuit and two DC input branches with the same structure; The input ends of the two DC input branches are respectively connected to the DC power supply through the DC switch, and the output ends of the two DC input branches are respectively connected to the inverter circuit through the DC bus. The DC power supply is used to supply power to the inverter circuit through any DC input branch; The DC input branch includes a slow-start component, a fast forward conducting positive component, a fast reverse conducting positive component, a fast forward conducting negative component and a fast reverse conducting negative component, wherein the slow-start component, the fast forward conducting positive component and the fast reverse conducting positive component are arranged in parallel between the positive pole of the input terminal of the DC input branch and the positive pole of the DC bus, and the fast forward conducting negative component and the fast reverse conducting negative component are arranged in parallel between the negative pole of the input terminal of the DC input branch and the negative pole of the DC bus; The slow-start component is used to limit the DC input current to a safe value when the main power is first applied; The fast forward conducting positive electrode component and the fast forward conducting negative electrode component are used to conduct forward conduction on the DC input branch, so that the DC power supply supplies power to the inverter circuit; The fast reverse conducting positive electrode component and the fast reverse conducting negative electrode component are used to reverse conduct the DC input branch, so that the inverter circuit feeds the active current back to the input end of the DC input branch; The inverter circuit is used to convert the input DC power into AC power for output.

2. The high-power bidirectional dual-path DC input switching device according to claim 1, characterized in that: The input end of the slow-start component is connected to the positive input end of the DC input branch, and the output end of the slow-start component is connected to the positive pole of the DC bus; The slow-start component is composed of a diode and a resistor connected in series, wherein the resistor is used to slow down the rate of current rise, and the diode is used to limit the current to conduct forward.

3. The high-power bidirectional dual-path DC input switching device according to claim 1, characterized in that: The input end of the fast forward conducting positive electrode assembly is connected to the positive input end of the DC input branch, and the output end of the fast forward conducting positive electrode assembly is connected to the positive electrode of the DC bus; The fast forward conducting positive electrode component is composed of a thyristor rectifier, a capacitor, a resistor and a diode. The resistor and the diode are connected in parallel, and the whole formed in parallel is connected in series with the capacitor. The whole formed by the capacitor, the resistor and the diode is connected in parallel with the thyristor rectifier. The thyristor rectifier is used to control the on and off of the fast forward conducting positive electrode component. The capacitor is used to smooth the voltage changes of the fast forward conducting positive electrode component through the charging and discharging process. The resistor is used to prevent excessive current from passing through and causing damage to the components. The diode is used to prevent current from flowing in the fast forward conducting positive electrode component.

4. The high-power bidirectional dual-path DC input switching device according to claim 3, characterized in that: The direction of the anode of the thyristor rectifier is the input end of the fast forward conducting positive electrode component, the direction of the cathode of the thyristor rectifier is the output end of the fast forward conducting positive electrode component, and the control electrode of the anode of the thyristor rectifier is connected to the drive circuit.

5. The high-power bidirectional dual-path DC input switching device according to claim 4, characterized in that: The input end of the fast reverse conducting positive electrode component is connected to the positive electrode of the DC bus, and the output end of the fast reverse conducting positive electrode component is connected to the positive electrode of the input end of the DC input branch; The composition structure of the fast reverse conducting positive electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conducting direction of the fast reverse conducting positive electrode assembly is opposite to that of the fast forward conducting positive electrode assembly.

6. The high-power bidirectional dual-path DC input switching device according to claim 3, characterized in that: The input end of the fast forward conducting negative electrode component is connected to the negative electrode of the input end of the DC input branch, and the output end of the fast forward conducting negative electrode component is connected to the negative electrode of the DC bus; The composition structure of the fast forward conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conduction direction of the fast forward conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly.

7. The high-power bidirectional dual-path DC input switching device according to claim 4, characterized in that: The input end of the fast reverse conducting negative electrode component is connected to the positive pole of the DC bus, and the output end of the fast reverse conducting negative electrode component is connected to the positive pole of the input end of the DC input branch; The composition structure of the fast reverse conducting negative electrode assembly is the same as that of the fast forward conducting positive electrode assembly, and the conducting direction of the fast reverse conducting negative electrode assembly is opposite to that of the fast forward conducting positive electrode assembly.

8. The high-power bidirectional dual-path DC input switching device according to claim 1, characterized in that: The high-power bidirectional dual-channel DC input switching device also includes a voltage sampling component, which is respectively arranged at the DC input branch input end and the DC bus, and is used to measure the voltage of the DC input branch input end and the DC bus.

9. The high-power bidirectional dual-path DC input switching device according to claim 8, characterized in that: The high-power bidirectional dual-path DC input switching device further includes a drive circuit and a controller; The driving circuit is used to control the on and off of the fast forward conducting positive electrode component, the fast reverse conducting positive electrode component, the fast forward conducting negative electrode component and the fast reverse conducting negative electrode component through a trigger signal; The controller is used to control the drive circuit to send trigger signals to various components according to the voltage values ​​of the DC input branch input terminal and the DC bus.

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