Inverter pre-charge start control device

Abstract

The application provides an inverter pre-charging starting control device, which comprises a plurality of AC input ports, a plurality of pre-charging flyback circuits, a bus capacitor group and a pre-charging transformer. Each AC input port is connected with one pre-charging flyback circuit. The pre-charging flyback circuit comprises the pre-charging transformer, the primary winding of the pre-charging transformer is connected with the AC input port, the pre-charging transformer is provided with a first secondary winding and a second secondary winding with equal number of turns. The bus capacitor group comprises an upper bus capacitor and a lower bus capacitor. The first secondary winding of each pre-charging flyback circuit is coupled with the upper bus capacitor, and the second secondary winding of each pre-charging flyback circuit is coupled with the lower bus capacitor. The application avoids the defects of excessive capacitor voltage difference and long-term use bulge damage in the related art, reduces the device conduction and switching loss, reduces the heat generation, and does not need to additionally add a heat dissipation structure.

Description

Technical Field

[0001] This invention relates to the field of energy storage equipment technology, and more specifically, to an inverter precharge start-up control device. Background Technology

[0002] Existing multi-AC input energy storage inverters mostly adopt a single-winding integrated pre-charge topology to charge the series bus capacitors as a whole. Multiple AC inputs require separate independent bus energy storage capacitors and high-power pre-charge resistors and relays, resulting in a large number of components, a large PCB area, and high material and assembly costs. Furthermore, single-winding pre-charge cannot independently charge the upper and lower bus capacitors, which can easily lead to excessive voltage difference between the two series bus capacitors during power-on. Long-term accumulation of voltage difference can cause capacitor aging, bulging, and failure. At the same time, the single winding must withstand the total voltage of the entire bus, resulting in high voltage stress on the diodes and switching transistors in the pre-charge circuit. Only high-voltage, high-cost power devices can be selected, which result in large conduction and switching losses and severe heat generation, requiring additional heat dissipation structures. Summary of the Invention

[0003] The present invention aims to solve the technical problems existing in the prior art or related technologies.

[0004] Therefore, the first aspect of the present invention provides an inverter precharge start-up control device.

[0005] In view of the above, according to a first aspect of the present invention, an inverter precharge start-up control device is provided, wherein the inverter precharge start-up control device includes: a plurality of AC input ports; a plurality of precharge flyback circuits, each AC input port being connected to a precharge flyback circuit; each precharge flyback circuit includes a precharge transformer, the primary winding of the precharge transformer being connected to the AC input port, the precharge transformer having a first secondary winding and a second secondary winding with equal turns; a bus capacitor bank, the bus capacitor bank including an upper bus capacitor and a lower bus capacitor, the first secondary winding of each precharge flyback circuit being coupled to the upper bus capacitor, and the second secondary winding of each precharge flyback circuit being coupled to the lower bus capacitor; a double-ended flyback auxiliary power supply circuit, the first input winding of the double-ended flyback auxiliary power supply circuit being connected across the upper bus capacitor. The second input winding is connected across the two ends of the lower bus capacitor; multiple main relays are configured for each AC input port; an inverter power unit is connected in series with the bus capacitor bank, and the input terminal of the inverter power unit is connected to multiple AC input ports through multiple main relays; in response to AC power being connected to any AC input port, the pre-charge flyback circuit corresponding to the AC input port connected to AC power is turned on, and AC power charges the upper bus capacitor and the lower bus capacitor respectively through the first secondary winding and the second secondary winding; when the total bus voltage rises to the auxiliary power start threshold, the double-ended flyback auxiliary power circuit starts to work; when the total bus voltage is higher than the preset cutoff voltage, the main relay is closed, and after waiting for a preset time, the pre-charge flyback circuit is turned off.

[0006] The inverter pre-charge start-up control device provided by this invention mainly includes: multiple AC input ports, multiple pre-charge flyback circuits, a bus capacitor bank, a double-ended flyback auxiliary power circuit, multiple main relays, and an inverter power unit. The AC input ports are interfaces for connecting to external AC power sources such as mains power or generators. Each AC input port is individually matched with a pre-charge flyback circuit, and each pre-charge flyback circuit includes a pre-charge transformer. The pre-charge transformer is a magnetic component that achieves high- and low-voltage electrical isolation and outputs two equal-amplitude charging voltages. The primary winding of the pre-charge transformer is connected to the corresponding AC input port. The pre-charge transformer also has two sets of identical first and second secondary windings. The bus capacitor bank is a series energy storage capacitor for storing high-voltage DC energy. The bus capacitor bank includes an upper bus capacitor and a lower bus capacitor. The first secondary winding of all pre-charge transformers is uniformly connected to the upper bus capacitor, and the second secondary winding is uniformly connected to the lower bus capacitor. The dual-ended flyback auxiliary power supply circuit is an isolated power supply that powers the overall control and drive circuits and balances the bus capacitor voltage. It has a first input winding and a second input winding. The first input winding is connected across the two ends of the upper bus capacitor, and the second input winding is connected across the two ends of the lower bus capacitor. The two input windings are the primary coils of the auxiliary transformer in the dual-ended flyback auxiliary power supply circuit, connected in parallel to the two bus sections. Each AC input port is equipped with a separate high-power main relay, which is a high-power switching device that controls the AC power supply to the bus. The inverter power unit is simultaneously connected to the bus capacitor bank, and its input terminals are connected to each AC input port through all the main relays. The inverter power unit is the core power circuit that realizes bidirectional conversion between DC and AC power.

[0007] When the equipment is running, as long as any AC input port is connected to AC power, the pre-charge flyback circuit of the corresponding branch will start working. The AC power charges the upper bus capacitor and the lower bus capacitor independently and synchronously through the first secondary winding and the second secondary winding, respectively, continuously raising the total bus voltage. When the total bus voltage rises to the auxiliary power supply start threshold, the double-ended flyback auxiliary power supply circuit starts working. After the total bus voltage rises to a preset cutoff voltage higher than the peak value of the AC input, the corresponding main relay is closed, and the AC power supply directly supplies power to the main bus capacitor. After waiting for a preset time to confirm that the auxiliary power supply output is stable, the pre-charge flyback circuit is turned off. If the total bus voltage drops below the peak value of the AC input during operation, the main relay is disconnected and the pre-charge flyback circuit is restarted to raise the bus voltage. The preset cutoff voltage is the bus voltage threshold at which the pre-charge circuit stops building up voltage, and the preset time is the buffer time for waiting for the auxiliary power supply to work stably.

[0008] This invention features multiple AC input ports, each matched with an independent pre-charge flyback circuit. All pre-charge branches share the same bus capacitor bank consisting of an upper and lower bus capacitor. This eliminates the need for separate high-voltage bus energy storage capacitors and power devices for each AC input, significantly reducing the number of components, shrinking the PCB layout area, lowering material costs, and simplifying assembly. It is compatible with various AC power supplies, including split-phase mains, split-phase generators, and single-phase mains, making it suitable for a wider range of applications. Furthermore, the pre-charge transformer incorporates two independent secondary windings with identical turns. These windings independently charge the upper and lower bus capacitors, ensuring no interference between the two charging circuits. If the voltage of either bus capacitor is too low, the corresponding secondary winding will output more charging energy. During power-on pre-charge, the voltage across the two series-connected bus capacitors is dynamically balanced in real time, avoiding the excessive capacitor voltage difference and bulging damage associated with traditional single-winding pre-charge schemes. This improves the overall lifespan and operational reliability of the device. Simultaneously, the two sets of secondary windings are independently supplied to the two bus capacitors. A single secondary winding only bears half of the total bus voltage. The reverse withstand voltage of the secondary and primary switching transistors of the pre-charge transformer is halved, allowing the use of power devices with lower withstand voltage specifications and lower costs. The operating voltage of the devices is lower, and the switching loss and conduction loss are reduced simultaneously, resulting in less circuit heat generation. Furthermore, in this invention, the main relay is closed when the total bus voltage is higher than the peak value of the AC input, allowing the AC input to directly supply power to the bus capacitors. The pre-charge flyback circuit only operates for a short time during the power-on voltage build-up phase and does not require long-term load operation. The power devices in the pre-charge branch generate low heat, eliminating the need for additional heat dissipation structures, and natural heat dissipation is sufficient to meet the temperature rise standard.

[0009] In some technical solutions, optionally, the pre-charge flyback circuit includes: a first diode, the anode of which is connected to a first secondary winding, and the cathode of which is connected to an upper bus capacitor; a first capacitor, one end of which is connected to the cathode of the first diode and the upper bus capacitor, and the other end of which is connected to the first secondary winding; a second diode, the anode of which is connected to a second secondary winding, and the cathode of which is connected to a lower bus capacitor; and a second capacitor, one end of which is connected to the cathode of the second diode, and the other end of which is connected to a second secondary winding and the lower bus capacitor.

[0010] In some technical solutions, the precharge flyback circuit may optionally include: a first resistor, one end of which is connected to the AC input port; a rectifier circuit, one end of which is connected to the other end of the first resistor; and a third capacitor, one end of which is connected to the other end of the rectifier circuit, and the other end of which is connected to the primary winding of the precharge transformer.

[0011] In some technical solutions, the precharge flyback circuit may optionally include a first switching transistor, one end of which is connected to the rectifier circuit and the other end of which is connected to the primary winding, for receiving pulse signals and controlling the precharge transformer to store and release energy according to the pulse signals.

[0012] In some technical solutions, optionally, the dual-ended flyback auxiliary power supply circuit includes: an auxiliary transformer, the primary winding of which includes: a first input winding and a second input winding, the first end of the first input winding being connected to the first end of the upper bus capacitor, and the first end of the second input winding being connected to the first end of the lower bus capacitor; a second switching transistor, one end of which is connected to the second end of the first input winding, and the other end of which is connected to the second end of the upper bus capacitor; and a third switching transistor, one end of which is connected to the second end of the second input winding, and the other end of which is connected to the second end of the lower bus capacitor.

[0013] In some technical solutions, the auxiliary transformer may optionally include: a plurality of third secondary windings, the first end of the third secondary windings being connected to the first end of the fourth capacitor via a third diode, and the second end of the third secondary windings being connected to the second end of the fourth capacitor.

[0014] In some technical solutions, optionally, the inverter power unit includes: a first inductor, one end of which is connected to the bus capacitor bank, and the other end of which is connected to the first live wire input port of a plurality of AC input ports; a second inductor, one end of which is connected to the bus capacitor bank, and the other end of which is connected to the second live wire input port of a plurality of AC input ports; and a third inductor, one end of which is connected to the neutral wire input port of a plurality of AC input ports, and the other end of which is connected to the input terminal of the inverter power unit.

[0015] In some technical solutions, the inverter power unit may optionally include a full-bridge inverter circuit, one end of which is connected to the first inductor and the second inductor respectively, and the other end of which is connected to the bus capacitor bank.

[0016] In some technical solutions, the inverter power unit may optionally include: a fourth switching transistor, one end of which is connected to the positive terminal of the bus capacitor bank, and the other end of which is connected to the third inductor; and a fifth switching transistor, one end of which is connected to the negative terminal of the bus capacitor bank, and the other end of which is connected to the other end of the fourth switching transistor and the third inductor.

[0017] In some technical solutions, the inverter power unit may optionally include: a bidirectional buck-boost circuit, one end of which is connected to the bus capacitor bank; a resonant circuit, one end of which is connected to the other end of the bidirectional buck-boost circuit; and a bidirectional DC-DC circuit, one end of which is connected to the other end of the resonant circuit, and the other end of which is connected to the battery.

[0018] In some technical solutions, the AC input port may optionally include any one of the following: a single-phase AC input port, a split-phase AC input port, a split-phase generator input port, and a single-phase generator input port.

[0019] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 One of the schematic block diagrams of an inverter precharge start-up control device according to an embodiment of the present invention is shown;

[0022] Figure 2 One of the structural schematic diagrams of an inverter precharge start-up control device according to an embodiment of the present invention is shown;

[0023] Figure 3 A second schematic diagram of the inverter precharge start-up control device according to an embodiment of the present invention is shown.

[0024] Figure 4 The third schematic diagram shows the structure of an inverter precharge start-up control device according to an embodiment of the present invention;

[0025] Figure 5 A flowchart of the operation of an inverter precharge start-up control device according to an embodiment of the present invention is shown.

[0026] in, Figures 1 to 4 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0027] 10 Inverter pre-charge start-up control device, 102 AC input port, 104 Pre-charge flyback circuit, 106 Pre-charge transformer, 108 Primary winding, 110 First secondary winding, 112 Second secondary winding, 114 Bus capacitor bank, 116 Upper bus capacitor, 118 Lower bus capacitor, 120 Double-ended flyback auxiliary power supply circuit, 122 First input winding, 124 Second input winding, 126 Main relay, 128 Inverter power unit, D1 First and Second... Diode, C1 (first capacitor), D2 (second diode), C2 (second capacitor), R1 (first resistor), 130 rectifier circuit, C3 (third capacitor), Q1 (first switching transistor), T2 (auxiliary transformer), Q2 (second switching transistor), Q3 (third switching transistor), BUS+ bus positive terminal, BUS- bus negative terminal, BUS_MID bus midpoint, 132 third secondary winding, D3 (third diode), C4 (fourth capacitor), V+ (positive terminal of low-voltage power supply), V_GND (positive terminal of low-voltage power supply). Reference ground, L1 first inductor, L2 second inductor, L3 third inductor, 134 full-bridge inverter circuit, Q4 fourth switch, Q5 fifth switch, 136 bidirectional buck-boost circuit, 138 resonant circuit, 140 bidirectional DC-DC circuit, Q6 sixth switch, Q7 seventh switch, Q8 eighth switch, Q9 ninth switch, Q10 tenth switch, Q11 eleventh switch, Q12 twelfth switch, Q13 thirteenth switch, C5 fifth capacitor, Q14 fourteenth switch, Q15 fifteenth switch, Q16 sixteenth switch, Q17 seventeenth switch, L4 fourth inductor, C6 sixth capacitor, C7 seventh capacitor, Q18 eighteenth switch, Q19 nineteenth switch, Q20 twentieth switch, Q21 twenty-first switch, L5 first live wire input port, L6 second live wire input port, N neutral wire input port, C8 eighth capacitor, C9 ninth capacitor. Detailed Implementation

[0028] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0030] like Figure 1 and Figure 2As shown, this invention proposes an inverter pre-charge start-up control device 10, which includes: multiple AC input ports 102; multiple pre-charge flyback circuits 104, each AC input port 102 being connected to a corresponding pre-charge flyback circuit 104; each pre-charge flyback circuit 104 includes a pre-charge transformer 106, the primary winding 108 of which is connected to the AC input port 102, and the pre-charge transformer 106 having a first winding with an equal number of turns. A primary winding 110 and a secondary winding 112; a bus capacitor bank 114, comprising an upper bus capacitor 116 and a lower bus capacitor 118, wherein the first secondary winding 110 of each precharge flyback circuit 104 is coupled to the upper bus capacitor 116, and the second secondary winding 112 of each precharge flyback circuit 104 is coupled to the lower bus capacitor 118; a double-ended flyback auxiliary power supply circuit 120, wherein the first input winding 122 of the double-ended flyback auxiliary power supply circuit 120 is connected across the upper bus capacitor. The second input winding 124 is connected across the two ends of the lower bus capacitor 118; multiple main relays 126 are configured for each AC input port 102; an inverter power unit 128 is connected in series with the bus capacitor bank 114, and the input terminal of the inverter power unit 128 is connected to multiple AC input ports 102 through multiple main relays 126; in response to AC power being connected to any AC input port 102, the pre-charge flyback circuit 104 corresponding to the AC input port 102 connected to AC power is turned on, and AC power charges the upper bus capacitor 116 and the lower bus capacitor 118 through the first secondary winding 110 and the second secondary winding 112 respectively; when the total bus voltage rises to the auxiliary power start threshold, the double-ended flyback auxiliary power circuit 120 starts to work; when the total bus voltage is higher than the preset cutoff voltage, the main relay 126 is closed, and after waiting for a preset time, the pre-charge flyback circuit 104 is turned off.

[0031] The inverter precharge start-up control device 10 provided by this invention mainly includes: multiple AC input ports 102, multiple precharge flyback circuits 104, bus capacitor bank 114, dual-ended flyback auxiliary power circuit 120, multiple main relays 126, and inverter power unit 128. The AC input ports 102 are interfaces for connecting to external AC power sources such as mains power or generators. Each AC input port 102 is individually matched with a precharge flyback circuit 104. Each precharge flyback circuit 104 includes a precharge transformer 106, which is a magnetic element that achieves high and low voltage electrical isolation and outputs two equal-amplitude charging voltages. The primary winding 108 of the precharge transformer 106 is connected to the corresponding AC input port. The precharge transformer 106 is also equipped with two sets of identical first secondary windings 110 and second secondary windings 112. Bus capacitor bank 114 is a series energy storage capacitor for storing high-voltage DC power in the entire unit. Bus capacitor bank 114 includes upper bus capacitor 116 and lower bus capacitor 118, which are connected in series. The positive terminal of upper bus capacitor 116 is the positive terminal of the bus (BUS+), and the negative terminal of lower bus capacitor 118 is the negative terminal of the bus (BUS-). The center point between upper bus capacitor 116 and lower bus capacitor 118 is the bus midpoint (BUS_MID). The first secondary winding 110 of all pre-charge transformers 106 is uniformly connected to the upper bus capacitor 116, and the second secondary winding 112 is uniformly connected to the lower bus capacitor 118. The dual-ended flyback auxiliary power supply circuit 120 is an isolated power supply that provides power to the overall control and drive circuits and balances the bus capacitor voltage. The dual-ended flyback auxiliary power supply circuit 120 has a first input winding 122 and a second input winding 124. The first input winding 122 is connected across the two ends of the upper bus capacitor 116, and the second input winding 124 is connected across the two ends of the lower bus capacitor 118. The two input windings are the primary coils of the auxiliary transformer T2 in the dual-ended flyback auxiliary power supply circuit 120, connected in parallel to the two bus sections. Each AC input port is equipped with a separate high-power main relay 126, which is a high-power on / off device that controls the AC power supply to the bus. The inverter power unit 128 is simultaneously connected to the bus capacitor bank 114, and the input terminal of the inverter power unit 128 is connected to each AC input port through all the main relays 126. The inverter power unit 128 is the core power circuit that realizes bidirectional conversion between DC and AC power.

[0032] When the equipment is running, as long as any AC input port 102 is connected to AC power, the pre-charge flyback circuit 104 of the corresponding branch will start working. The AC power charges the upper bus capacitor 116 and the lower bus capacitor 118 independently and synchronously through the first secondary winding 110 and the second secondary winding 112, respectively, continuously raising the total bus voltage. When the total bus voltage rises to the auxiliary power supply start threshold, the double-ended flyback auxiliary power supply circuit starts working. After the total bus voltage rises to a preset cutoff voltage higher than the peak value of the AC input, the corresponding main relay 126 is closed, and the AC power supply directly supplies power to the main bus capacitor. After waiting for a preset time to confirm that the auxiliary power supply output is stable, the pre-charge flyback circuit 104 is turned off. If the total bus voltage drops below the peak value of the AC input during operation, the main relay 126 is disconnected and the pre-charge flyback circuit 104 is restarted to raise the bus voltage. The preset cutoff voltage is the bus voltage threshold at which the pre-charge circuit stops building up voltage, and the preset time is the buffer time for waiting for the auxiliary power supply to work stably.

[0033] This invention sets up multiple AC input ports 102, each matched with an independent pre-charge flyback circuit 104. All pre-charge branches share the same bus capacitor group 114 consisting of an upper bus capacitor 116 and a lower bus capacitor 118. This eliminates the need to configure a separate high-voltage bus energy storage capacitor and matching power devices for each AC input, significantly reducing the number of components in the whole machine, shrinking the PCB (Printed Circuit Board) layout area, reducing material costs and assembly difficulty. It can simultaneously support multiple AC power supplies such as split-phase mains, split-phase generator, and single-phase mains, making it applicable to a wider range of scenarios. Meanwhile, two sets of independent secondary windings with exactly the same number of turns are set in the pre-charge transformer 106. The two windings charge the upper bus capacitor 116 and the lower bus capacitor 118 separately in isolation. The two charging circuits do not interfere with each other. If the voltage of either bus capacitor is too low, the corresponding secondary winding will output more charging energy. During the power-on pre-charge process, the voltage across the two series-connected bus capacitors is dynamically balanced in real time. This avoids the defects of excessive capacitor voltage difference and bulging damage after long-term use in the traditional single-winding overall pre-charge scheme, and improves the service life and operational reliability of the whole machine. Simultaneously, the two sets of secondary windings are independently supplied to the two bus capacitors. A single secondary winding only bears half of the total bus voltage. The reverse withstand voltage of the secondary and primary switching transistors of the pre-charge transformer 106 is halved, allowing the use of power devices with lower withstand voltage specifications and lower cost. The device operating voltage is lower, and the switching loss and conduction loss are reduced simultaneously, resulting in less circuit heat generation. Furthermore, in this invention, the main relay 126 is closed when the total bus voltage is higher than the peak value of the AC input, allowing the AC input to directly supply power to the bus capacitors. The pre-charge flyback circuit 104 only operates for a short time during the power-on voltage build-up phase and does not require long-term load operation. The power devices in the pre-charge branch generate low heat and do not require additional heat dissipation structures; natural heat dissipation is sufficient to meet the temperature rise standard.

[0034] Meanwhile, this invention simplifies the overall structure. The two input windings of the dual-ended flyback auxiliary power circuit 120 are respectively connected across the upper bus capacitor 116 and the lower bus capacitor 118, enabling independent acquisition of the two bus voltages and independent power supply. Under all operating conditions of inverter standby, light load, and inverter load, it continuously consumes the excess energy of the bus capacitor with the higher voltage side. Based on the pre-charge voltage equalization, a steady-state continuous voltage equalization mechanism is formed, providing double protection for the stable operation of the bus capacitors. The pre-charge flyback transformer and the dual-ended flyback auxiliary power transformer respectively achieve electrical isolation between the AC input side, the high-voltage bus side, and the low-voltage control side. There is no direct electrical connection between the high and low voltages, which meets the safety regulations for energy storage inverters regarding isolation distance and insulation withstand voltage, resulting in higher safety. The inverter power unit 128 is simultaneously connected to the bus capacitor bank 114 and multiple AC input ports. 102. When AC input is connected, the inverter power unit 128 can perform active rectification to convert AC power into DC power and store it in the bus capacitor. When the bus capacitor stores DC power, the inverter power unit 128 can invert DC power into industrial frequency AC power for external output. One device can simultaneously realize two working modes: mains power / generator charging and battery inverter off-grid backup power. It has a high degree of functional integration. The whole pre-charge start-up sequence is controlled in layers. First, the pre-charge branch is started to slowly raise the bus voltage. After the bus reaches the standard, the auxiliary power supply control circuit is started. After the voltage reaches the cutoff threshold, the main relay 126 is closed to switch to high-power direct supply, smoothly establish the high voltage of the bus, eliminate the huge surge impact caused by the direct closing of the main relay 126, effectively protect the core high-power components such as the inverter power unit 128 and the bus capacitor, and reduce the probability of overall machine failure.

[0035] In some embodiments, optionally, such as Figure 2 As shown, the pre-charge flyback circuit 104 includes: a first diode D1, the anode of which is connected to the first secondary winding 110, and the cathode of which is connected to the upper bus capacitor 116; a first capacitor C1, one end of which is connected to the cathode of the first diode D1 and the upper bus capacitor 116, and the other end of which is connected to the first secondary winding 110; a second diode D2, the anode of which is connected to the second secondary winding 112, and the cathode of which is connected to the lower bus capacitor 118; and a second capacitor C2, one end of which is connected to the cathode of the second diode D2, and the other end of which is connected to the second secondary winding 112 and the lower bus capacitor 118.

[0036] In this embodiment, the pre-charge flyback circuit 104 includes a first diode D1, a first capacitor C1, a second diode D2, and a second capacitor C2. The first diode D1 and the second diode D2 are unidirectional rectifier devices, corresponding to the first secondary winding 110 and the second secondary winding 112, respectively, and can prevent the high voltage of the bus capacitor from flowing back into the windings of the pre-charge transformer 106. The first capacitor C1 and the second capacitor C2 are buffer filter capacitors connected in parallel in the secondary circuit, used to smooth the charging current and suppress voltage spikes. The output terminal of the first secondary winding 110 of the pre-charge transformer 106 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the upper bus capacitor 116, and the first capacitor C1 is connected in parallel across the first diode D1 and the first secondary winding 110, i.e., the first capacitor C1 is connected in parallel with the upper bus capacitor 116. The output terminal of the second secondary winding 112 is connected to the anode of the second diode D2. The cathode of the second diode D2 is connected to the lower bus capacitor 118 through the second capacitor C2. The second capacitor C2 is arranged in parallel across the second diode D2 and the second secondary winding 112, i.e., the second capacitor C2 is connected in parallel with the lower bus capacitor 118. During the operation of the equipment, the alternating voltage generated by the precharge transformer 106 being turned off and releasing magnetic energy will be rectified into DC power by the first diode D1 and the second diode D2 in one direction, and then delivered to the upper bus capacitor 116 and the lower bus capacitor 118 respectively to complete the charging. The first capacitor C1 and the second capacitor C2 continuously absorb the high-frequency switching ripple generated by the rectifier circuit and the voltage spike at the moment of diode turn-off, stabilizing the output voltage amplitude of the two windings and enhancing the voltage balance effect of the upper bus capacitor 116 and the lower bus capacitor 118 during the precharge process. This invention, by setting a first diode D1 and a second diode D2, relies on the unidirectional conduction characteristics of the diodes to block the reverse current of the bus capacitor, protect the pre-charge transformer 106 winding from reverse high voltage impact, and the buffer capacitor can absorb the instantaneous high voltage spike of the switch, reduce the diode withstand voltage selection standard, filter out high frequency pulsating current, keep the two charging voltages stable, reduce the bus capacitor voltage difference, and also suppress high frequency switching harmonics and reduce the electromagnetic interference of the whole machine.

[0037] In some embodiments, optionally, such as Figure 2 As shown, the precharge flyback circuit 104 includes: a first resistor R1, one end of which is connected to the AC input port 102; a rectifier circuit 130, one end of which is connected to the other end of the first resistor R1; and a third capacitor C3, one end of which is connected to the other end of the rectifier circuit 130, and the other end of which is connected to the primary winding 108 of the precharge transformer 106.

[0038] In this embodiment, the pre-charge flyback circuit 104 includes a first resistor R1, a rectifier circuit 130, and a third capacitor C3. The first resistor R1 is a current-limiting resistor connected in series at the AC input terminal to reduce power-on surge current. The rectifier circuit 130 is a full-bridge rectifier circuit composed of four diodes, converting AC to DC. The third capacitor C3 is a primary-side filter capacitor connected in parallel at the output terminal of the rectifier circuit 130 to smooth the DC input voltage. The AC input port 102 is first connected in series with the first resistor R1 to suppress power-on surge current. The rear end of the first resistor R1 is connected to the full-bridge rectifier circuit 130. The output terminal of the rectifier circuit 130 is connected in parallel with the third capacitor C3. The rectified and filtered stable DC voltage is directly supplied to the primary winding 108 of the pre-charge transformer 106. When the device is powered on, the external AC power first passes through the first resistor R1 to weaken the instantaneous surge current, and then the rectifier circuit 130 converts the power frequency AC power into pulsating DC power. The third capacitor C3 filters out the power frequency pulsating component, and a stable DC voltage is output to the primary winding 108 of the pre-charge transformer 106, avoiding drastic changes in the pre-charge current caused by AC voltage fluctuations. By setting the first resistor R1, this invention can suppress the ultra-large inrush current at the moment of power-on, avoiding overcurrent burnout of the rectifier diodes. By setting the rectifier circuit 130 and the third capacitor C3, the rectifier circuit 130 converts the power frequency AC power into a DC voltage suitable for the operation of the flyback transformer, and the third capacitor C3 eliminates the power frequency voltage pulsation, ensuring a stable input voltage for the pre-charge transformer 106, a controllable bus voltage rise curve, and improved bus voltage sampling and control accuracy.

[0039] In some embodiments, optionally, such as Figure 2 As shown, the precharge flyback circuit 104 also includes a first switch Q1, one end of which is connected to the rectifier circuit 130, and the other end of which is connected to the primary winding 108. It is used to receive pulse signals and control the precharge transformer 106 to store and release energy according to the pulse signals.

[0040] In this embodiment, the pre-charge flyback circuit 104 further includes a first switching transistor Q1. The first switching transistor Q1 is connected in series between the rectifier circuit 130 and the primary winding 108 of the pre-charge transformer 106. The first switching transistor Q1 is a power transistor that controls the energy storage and release of the pre-charge transformer 106. The first switching transistor Q1 can receive pulse signals, i.e., PWM signals, and control the pre-charge transformer 106 to store and release energy according to the pulse signals. The pulse signal is a high-frequency square wave drive signal output by the controller, used to adjust the duty cycle of the first switching transistor Q1. For example, the controller outputs a high-frequency pulse signal to drive the first switching transistor Q1 to periodically turn on and off. During the on-phase of the first switching transistor Q1, the DC energy stored in the third capacitor C3 is sent to the primary winding 108 of the pre-charge transformer 106, and the transformer core stores magnetic field energy. During the turn-off phase of the first switch Q1, the primary circuit of the pre-charge transformer 106 is disconnected, and the magnetic energy stored in the pre-charge transformer 106 is released to the two sets of secondary windings. This energy then charges the bus capacitor through diodes and buffer capacitors. The controller adjusts the duty cycle of the pulse signal to change the conduction duration of the first switch Q1, thereby regulating the pre-charge output power and the bus voltage rise rate. By setting the first switch Q1, the pre-charge transformer 106 achieves energy storage and release cycles through the periodic switching of the first switch Q1, completing isolated charging between the AC side and the high-voltage bus, meeting the high and low voltage isolation safety requirements of energy storage equipment. The pre-charge rate can be flexibly controlled by adjusting the pulse duty cycle, adapting to the charging needs of large-capacity bus capacitors. Each switch is independently driven and controlled, and multiple input branches do not interfere with each other, reducing the overall no-load power consumption.

[0041] In some embodiments, optionally, such as Figure 3 As shown, the dual-ended flyback auxiliary power supply circuit 120 includes: an auxiliary transformer T2, the primary winding of which includes: a first input winding 122 and a second input winding 124, the first end of the first input winding 122 being connected to the first end of the upper bus capacitor 116, and the first end of the second input winding 124 being connected to the first end of the lower bus capacitor 118; a second switch Q2, one end of which is connected to the second end of the first input winding 122, and the other end of which is connected to the second end of the upper bus capacitor 116; and a third switch Q3, one end of which is connected to the second end of the second input winding 124, and the other end of which is connected to the second end of the lower bus capacitor 118.

[0042] In this embodiment, the dual-ended flyback auxiliary power supply circuit 120 includes an auxiliary transformer T2, a second switch Q2, and a third switch Q3. The auxiliary transformer T2 is a magnetic component that isolates the high-voltage bus from the low-voltage control power supply. The primary winding of the auxiliary transformer T2 includes two independent input windings: a first input winding 122 and a second input winding 124. The first end of the first input winding 122 is connected to the first end of the upper bus capacitor 116 (i.e., the positive terminal of the upper bus capacitor 116), and the other end of the first input winding 122 is connected in series with the second switch Q2 and then connected to the second end of the upper bus capacitor 116 (i.e., the negative terminal of the upper bus capacitor 116). The first end of the second input winding 124 is connected to the first end of the lower bus capacitor 118 (i.e., the positive terminal of the lower bus capacitor 118), and the other end of the second input winding 124 is connected in series with the third switch Q3 and then connected to the second end of the lower bus capacitor 118 (i.e., the negative terminal of the lower bus capacitor 118). The controller can synchronously output drive signals to control the synchronous switching of the second switch Q2 and the third switch Q3. When the switch is on, the corresponding bus capacitor supplies electrical energy to the corresponding input winding. The auxiliary transformer T2 stores magnetic energy. After the switch is off, the magnetic energy is released to the secondary side to output low-voltage control power. The two input windings independently draw power from the two bus sections. The winding corresponding to the bus capacitor with the higher voltage stores more energy in a single cycle, continuously consuming the excess energy of the higher-voltage capacitor, and automatically balancing the voltage of the upper and lower bus capacitors. The structure of independent competitive power drawing by the two input windings can continuously balance the voltage of the bus capacitors under standby, light load and full operating conditions, without the need for additional bus balancing hardware. One auxiliary power supply can simultaneously realize the low-voltage power supply and bus voltage equalization function of the whole machine, reducing the number of components and the area occupied by the printed circuit board.

[0043] In some embodiments, optionally, such as Figure 3 As shown, the auxiliary transformer T2 includes: multiple third secondary windings 132, the first end of the third secondary winding 132 is connected to the first end of the fourth capacitor C4 through the third diode D3, and the second end of the third secondary winding 132 is connected to the second end of the fourth capacitor C4.

[0044] In this embodiment, the auxiliary transformer T2 includes multiple third secondary windings 132. The double-ended flyback auxiliary power supply circuit 120 further includes multiple third diodes D3 and multiple fourth capacitors C4. Each third secondary winding 132 has a third diode D3 connected in series at one end, a fourth capacitor C4 connected in parallel at the output of the third diode D3, and the other end of the third secondary winding 132 connected to the other end of the fourth capacitor C4. Simultaneously, the first terminal of the fourth capacitor C4 serves as the positive terminal V+ of the low-voltage power supply, and the second terminal of the fourth capacitor C4 serves as the reference ground V_GND of the low-voltage power supply. After the magnetic energy of the auxiliary transformer T2 is released to the third secondary windings 132, the induced alternating voltage of the windings is unidirectionally rectified by the third diode D3 and then filtered by the fourth capacitor C4, outputting multiple isolated and stable low-voltage DC power supplies, which are respectively supplied to the main control DSP, driver chip, voltage sampling circuit, and cooling fan, among other low-voltage modules of the entire machine. The three sets of third secondary windings 132 are electrically isolated from each other, and the multiple low-voltage power supplies are output independently without crosstalk. Multiple independent secondary windings can output isolated low-voltage power supplies of different voltage levels, fully covering the power supply needs of all low-voltage modules in the whole machine. The rectifier and filter structure eliminates low-voltage output fluctuations and avoids false triggering of the main control and drive chips. The electrical isolation between windings can isolate the mutual interference between the high-voltage drive circuit and the low-voltage sampling circuit, improving the accuracy of voltage sampling and power control of the whole machine.

[0045] In some embodiments, optionally, such as Figure 4 As shown, the inverter power unit 128 includes: a first inductor L1, one end of which is connected to the bus capacitor bank 114, and the other end of which is connected to the first live wire input port L5 of the plurality of AC input ports 102; a second inductor L2, one end of which is connected to the bus capacitor bank 114, and the other end of which is connected to the second live wire input port L6 of the plurality of AC input ports 102; and a third inductor L3, one end of which is connected to the neutral wire input port N of the plurality of AC input ports 102, and the other end of which is connected to the input terminal of the inverter power unit 128.

[0046] In this embodiment, the inverter power unit 128 includes a first inductor L1, a second inductor L2, and a third inductor L3. The first inductor L1 and the second inductor L2 are LC filter inductors for the two live wires, filtering out high-frequency switching harmonics at the inverter output. The third inductor L3 is a neutral point buffer inductor, stabilizing the circulating current at the bus midpoint (BUS_MID). One end of the first inductor L1 is connected to the inverter output terminal of the bus capacitor bank 114, and the other end is connected to the first live wire input port L5 of each AC input port 102. One end of the second inductor L2 is connected to the inverter output terminal of the bus capacitor bank 114, and the other end is connected to the second live wire input port L6 of each AC input port 102. One end of the third inductor L3 is connected to the neutral wire input port N of each AC input port 102, and the other end is connected to the internal midpoint circuit of the inverter power unit 128. In inverter discharge mode, the high-voltage DC of the bus is modulated into high-frequency SPWM pulse AC by the inverter circuit. The first inductor L1 and the second inductor L2 filter out high-frequency harmonics on the live wire side, and the third inductor L3 suppresses the instantaneous current fluctuation at the neutral wire midpoint. In charging and rectification mode, the external AC mains power and generator AC power are filtered by the three inductors and then sent to the inverter circuit, converted into DC and stored in the bus capacitor, preventing the inverter switch harmonics from backflowing and polluting the external AC power grid. The first inductor L1 and the second inductor L2 block high-frequency switching components, outputting only standard power frequency sinusoidal AC power, reducing waveform distortion to suit household loads. The charging mode meets the grid-connected harmonic safety standards. At the same time, the third inductor L3 buffers the instantaneous circulating current at the bus midpoint BUS_MID, reducing the midpoint voltage fluctuation. Together with the pre-charge flyback circuit 104 and the double-ended flyback auxiliary power supply circuit 120, multiple voltage equalization of the bus capacitor is achieved.

[0047] For example, such as Figure 4 As shown, the output terminals of the first inductor L1 and the second inductor L2 are connected in parallel with the eighth capacitor C8 and the ninth capacitor C9, respectively. The two ends of the eighth capacitor C8 are connected to the first live wire input port L5 and the neutral wire input port N, respectively. The two ends of the ninth capacitor C9 are connected to the second live wire input port L6 and the neutral wire input port N, respectively, together forming the inverter output LC filter network. During operation, the high-frequency PWM pulse AC power generated by the full-bridge inverter circuit 134 is initially filtered out by the first inductor L1 and the second inductor L2. Then, the remaining high-frequency switching harmonics are absorbed by the eighth capacitor C8 and the ninth capacitor C9, smoothing the power frequency output voltage, filtering out carrier interference, reducing the distortion rate of the output AC power waveform, and outputting a standard symmetrical split-phase sinusoidal AC power to supply external split-phase mains power, split-phase generator, and single-phase mains load. Under the charging and rectification conditions, it can also block the backflow of external grid harmonics into the inverter power unit 128, reduce the AC side interference of the power switching tube, and suppress the instantaneous voltage spike of the output circuit to protect the external AC load at the downstream end.

[0048] In some embodiments, the inverter power unit 128 may optionally include a full-bridge inverter circuit 134, one end of which is connected to the first inductor L1 and the second inductor L2 respectively, and the other end of which is connected to the bus capacitor bank 114.

[0049] In this embodiment, the inverter power unit 128 further includes a full-bridge inverter circuit 134. The full-bridge inverter circuit 134 is an eight-transistor three-level split-phase power conversion bridge circuit, capable of bidirectional conversion between DC and AC power. The DC input terminal is connected in parallel with a bus capacitor bank 114, and the AC output terminals are respectively connected to the first inductor L1 and the second inductor L2. The controller outputs a PWM sinusoidal pulse drive signal to control the eight power switches inside the full-bridge inverter circuit 134 to alternately turn on and off. For example, the full-bridge inverter circuit 134 can be composed of a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12, and a thirteenth switch Q13. In inverter discharge mode, the full-bridge inverter circuit 134 converts the high-voltage DC of the bus into two symmetrical split-phase AC power, which is then filtered by the first inductor L1 and the second inductor L2 before being supplied to the outside. In charging rectification mode, the external AC power is filtered by the first inductor L1 and the second inductor L2 before being fed into the full-bridge inverter circuit 134. The full-bridge inverter circuit 134 uses the body diode of the switching transistor to complete active rectification, converting the AC power into DC power and storing it in the bus capacitor, thus realizing bidirectional energy flow.

[0050] In some embodiments, the inverter power unit 128 may optionally include: a fourth switch Q4, one end of which is connected to the positive terminal of the bus capacitor bank 114, and the other end of which is connected to the third inductor L3; and a fifth switch Q5, one end of which is connected to the negative terminal of the bus capacitor bank 114, and the other end of which is connected to the other end of the fourth switch Q4 and the third inductor L3.

[0051] In this embodiment, the inverter power unit 128 further includes a fourth switch Q4 and a fifth switch Q5. The fourth switch Q4 and the fifth switch Q5 are bus midpoint BUS_MID balancing power MOSFETs, used to dynamically adjust the bus midpoint BUS_MID potential and discharge excess energy from the bus capacitors. One end of the fourth switch Q4 is connected to the positive terminal of the bus capacitor bank 114, and the other end is connected to the midpoint circuit of the third inductor L3; one end of the fifth switch Q5 is connected to the negative terminal of the bus capacitor bank 114, and the other end is connected to the midpoint of the fourth switch Q4 and the third inductor L3. During high-power inverter and charging operations, the controller continuously monitors the voltage across the upper bus capacitor 116 and the lower bus capacitor 118. If the voltage of the upper bus capacitor 116 is too high, the fourth switch Q4 is intermittently turned on to release excess energy to the bus midpoint BUS_MID. If the voltage of the lower bus capacitor 118 is too high, the fifth switch Q5 is intermittently turned on to balance the voltage. When the equipment is shut down or under fault protection, the fourth switch Q4 and the fifth switch Q5 are turned on simultaneously to controllably and slowly discharge the residual high voltage of the bus capacitors. At the same time, the two switches work with the third inductor L3 to absorb the instantaneous impact circulating current at the midpoint, reducing the voltage ripple at the bus midpoint BUS_MID. The fourth switch Q4 and the fifth switch Q5 can actively balance the bus capacitor voltage under high-power dynamic operation conditions, forming a triple balance guarantee with the pre-charge voltage equalization and the steady-state voltage equalization of the dual-terminal flyback auxiliary source, continuously controlling the bus capacitor voltage difference within a very small range and avoiding long-term bias aging and bulging of the capacitors.

[0052] In some embodiments, the inverter power unit 128 may optionally include: a bidirectional buck-boost circuit 136, one end of which is connected to the bus capacitor bank 114; a resonant circuit 138, one end of which is connected to the other end of the bidirectional buck-boost circuit 136; and a bidirectional DC-DC circuit 140, one end of which is connected to the other end of the resonant circuit 138, and the other end of which is connected to the battery.

[0053] In this embodiment, the inverter power unit 128 further includes: a bidirectional buck-boost circuit 136, a resonant circuit 138, and a bidirectional DC-DC circuit 140. The bidirectional buck-boost circuit 136 is a high-power Buck-Boost converter circuit on the bus side. Exemplarily, the bidirectional buck-boost circuit 136 may be composed of a fifth capacitor C5, a fourteenth switch Q14, a fifteenth switch Q15, a sixteenth switch Q16, and a seventeenth switch Q17. The resonant circuit 138 is an LC buffer network for absorbing switching spikes. Exemplarily, the resonant circuit 138 may be composed of a fourth inductor L4 and a sixth capacitor C6. The bidirectional DC-DC circuit 140 is a low-voltage bidirectional converter circuit adapted to the energy storage battery voltage. Exemplarily, the bidirectional DC-DC circuit 140 may be composed of a seventh capacitor C7, an eighteenth switch Q18, a nineteenth switch Q19, a twentieth switch Q20, and a twenty-first switch Q21. The input terminal of the bidirectional buck-boost circuit 136 is connected to the bus capacitor bank 114, and the output terminal is connected in series with the resonant circuit 138. The other end of the resonant circuit 138 is connected to the bidirectional DC-DC circuit 140, which is connected to an external energy storage lithium battery. In the equipment discharge inverter mode, the battery power is boosted by the bidirectional DC-DC circuit 140, buffered by the resonant circuit 138, and boosted to the bus high voltage DC by the bidirectional buck-boost circuit 136, and then sent to the full-bridge inverter circuit 134 to be converted into AC power for external output. In the equipment charging energy storage mode, the bus high voltage power after rectification by the mains power and the generator is stepped down by the bidirectional buck-boost circuit 136, buffered by the resonant circuit, and adapted to the battery voltage by the bidirectional DC-DC circuit 140 to complete the charging of the energy storage battery. The resonant circuit 138 continuously absorbs the voltage spikes generated by the operation of the power switch, reducing energy conversion losses and widening the voltage range that the energy storage battery can adapt to.

[0054] In some embodiments, the AC input port 102 may optionally include any one of a single-phase AC input port 102, a split-phase AC input port 102, a split-phase generator input port, and a single-phase generator input port.

[0055] In this embodiment, the AC input port 102 includes any one of the following: a single-phase AC input port 102, a split-phase AC input port 102, a split-phase generator input port, and a single-phase generator input port. Specifically, the single-phase AC input port 102 is compatible with ordinary household single-phase mains power, the split-phase AC input port 102 is compatible with US standard 120 / 240V split-phase mains power, the split-phase generator input port is compatible with a 240V split-phase backup gasoline generator, and the single-phase generator input port is compatible with a small 220V single-phase gasoline generator. The pre-charge flyback circuit 104 and main relay 126 associated with the four types of AC input ports 102 have completely identical hardware structures, differing only in the type of external power supply. Connecting any type of port to the corresponding AC power supply will trigger the matching pre-charge flyback circuit 104 to start, fully executing the entire start-up control logic of bus pre-charging, auxiliary power supply power-on, and main relay 126 closing. Each type of port can be used independently or as redundant backup power inputs. After a mains power outage, switching the generator port will provide continuous power to the entire house.

[0056] Figure 5 A flowchart of the operation of an inverter precharge start-up control device according to an embodiment of the present invention is shown; wherein, the operation is as follows:

[0057] Step 502: The dual-ended flyback auxiliary power supply circuit operates, and the DSP detects the bus voltage and the input AC voltage;

[0058] Step 504: Determine if the bus voltage is greater than the peak value of the AC input voltage. If the result is yes, proceed to step 506; if the result is no, proceed to step 502.

[0059] Step 506: Engage the main relay;

[0060] Step 508: Determine if the bus voltage is greater than the peak value of the AC input voltage. If the result is yes, proceed to step 510; if the result is no, proceed to step 506.

[0061] Step 510: Waiting time 100ms;

[0062] Step 512: Turn off the precharge flyback circuit.

[0063] In this embodiment, the working process of the inverter precharge start-up control device is as follows: After the equipment starts, the dual-ended flyback auxiliary power circuit is put into operation. The main control DSP continuously collects the bus voltage value and the external AC input voltage value in real time and compares them. It continuously judges whether the current total bus voltage exceeds the peak value of the AC input voltage. If the bus voltage does not reach the peak value, the auxiliary power is maintained and the voltage detection and comparison operation is repeated. Only when the bus voltage is detected to be higher than the peak value of the AC input voltage will the main relay of the corresponding branch be controlled to complete the energizing action. After the main relay is energized, the DSP will continuously check whether the bus voltage is still higher than the peak value of the AC input voltage. Once the bus voltage falls back below the peak value, the control logic of energizing the main relay will be re-executed. After confirming that the bus voltage is stably higher than the peak value of the AC input voltage, the system enters a 100ms delay buffer stage. After the preset time expires, the controller outputs a shutdown signal to stop the precharge flyback circuit from working and complete the entire precharge start-up process.

[0064] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, unless otherwise expressly specified and limited. The terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An inverter pre-charge start-up control device, characterized in that, include: Multiple AC input ports; Multiple precharge flyback circuits, with each of the AC input ports connected to one of the precharge flyback circuits; The precharge flyback circuit includes a precharge transformer, the primary winding of which is connected to the AC input port, and the precharge transformer has a first secondary winding and a second secondary winding with equal turns. The bus capacitor bank includes an upper bus capacitor and a lower bus capacitor. The first secondary winding of each precharge flyback circuit is coupled to the upper bus capacitor, and the second secondary winding of each precharge flyback circuit is coupled to the lower bus capacitor. A dual-ended flyback auxiliary power source circuit, wherein the first input winding of the dual-ended flyback auxiliary power source circuit is connected across the two ends of the upper bus capacitor, and the second input winding is connected across the two ends of the lower bus capacitor; Multiple main relays, with one main relay configured for each of the AC input ports; An inverter power unit is connected in series with the bus capacitor bank, and the input terminal of the inverter power unit is connected to multiple AC input ports through multiple main relays. In response to AC power being connected to any of the AC input ports, the pre-charge flyback circuit corresponding to the AC input port connected to the AC power is turned on, and the AC power charges the upper bus capacitor and the lower bus capacitor respectively through the first secondary winding and the second secondary winding; when the total bus voltage rises to the auxiliary power start threshold, the dual-ended flyback auxiliary power circuit starts to work; when the total bus voltage is higher than the preset cutoff voltage, the main relay is closed, and after waiting for a preset time, the pre-charge flyback circuit is turned off.

2. The inverter pre-charge start-up control device according to claim 1, characterized in that, The pre-charge flyback circuit includes: The first diode has its anode connected to the first secondary winding and its cathode connected to the upper bus capacitor. The first capacitor has one end connected to the cathode of the first diode and the upper bus capacitor, and the other end connected to the first secondary winding. The second diode has its anode connected to the second secondary winding and its cathode connected to the lower bus capacitor. The second capacitor has one end connected to the cathode of the second diode and the lower bus capacitor, and the other end connected to the second secondary winding and the lower bus capacitor.

3. The inverter pre-charge start-up control device according to claim 1, characterized in that, The pre-charge flyback circuit includes: A first resistor, one end of which is connected to the AC input port; A rectifier circuit, one end of which is connected to the other end of the first resistor; The third capacitor has one end connected to the other end of the rectifier circuit and the other end connected to the primary winding of the precharge transformer.

4. The inverter pre-charge start-up control device according to claim 3, characterized in that, The precharge flyback circuit also includes: The first switching transistor has one end connected to the rectifier circuit and the other end connected to the primary winding. It is used to receive pulse signals and control the pre-charge transformer to store and release energy according to the pulse signals.

5. The inverter pre-charge start-up control device according to any one of claims 1 to 4, characterized in that, The dual-ended flyback auxiliary power source circuit includes: An auxiliary transformer, wherein the primary winding of the auxiliary transformer includes: a first input winding and a second input winding, wherein a first end of the first input winding is connected to a first end of the upper bus capacitor, and a first end of the second input winding is connected to a first end of the lower bus capacitor; The second switch has one end connected to the second end of the first input winding and the other end connected to the second end of the upper bus capacitor. The third switch is connected at one end to the second end of the second input winding and at the other end to the second end of the lower bus capacitor.

6. The inverter pre-charge start-up control device according to claim 5, characterized in that, The auxiliary transformer includes: Multiple third secondary windings, the first end of the third secondary winding is connected to the first end of the fourth capacitor through a third diode, and the second end of the third secondary winding is connected to the second end of the fourth capacitor.

7. The inverter pre-charge start-up control device according to any one of claims 1 to 4, characterized in that, The inverter power unit includes: A first inductor, one end of which is connected to the bus capacitor bank, and the other end of which is connected to the first live wire input port of the plurality of AC input ports; The second inductor has one end connected to the bus capacitor bank and the other end connected to the second live wire input port of the plurality of AC input ports. The third inductor has one end connected to the neutral input port of the plurality of AC input ports, and the other end connected to the input terminal of the inverter power unit.

8. The inverter pre-charge start-up control device according to claim 7, characterized in that, The inverter power unit also includes: A full-bridge inverter circuit, one end of which is connected to the first inductor and the second inductor respectively, and the other end of which is connected to the bus capacitor bank.

9. The inverter pre-charge start-up control device according to claim 7, characterized in that, The inverter power unit also includes: The fourth switch is connected at one end to the positive terminal of the bus capacitor bank and at the other end to the third inductor. The fifth switch is connected at one end to the negative terminal of the bus capacitor bank, and at the other end to the other end of the fourth switch and the third inductor.

10. The inverter pre-charge start-up control device according to claim 7, characterized in that, The inverter power unit also includes: A bidirectional buck-boost circuit, one end of which is connected to the bus capacitor bank; A resonant circuit, one end of which is connected to the other end of the bidirectional buck-boost circuit; A bidirectional DC-DC circuit, one end of which is connected to the other end of the resonant circuit, and the other end of which is connected to the battery.

11. The inverter pre-charge start-up control device according to any one of claims 1 to 4, characterized in that, The AC input port includes: Any one of the following: single-phase AC input port, split-phase AC input port, split-phase generator input port, and single-phase generator input port.

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