A split-phase inverter power supply system, control method, and controller

Abstract

This application relates to a split-phase inverter power supply system, control method, and controller. The system includes an L1 line inverter circuit, an L2 line inverter circuit, a first output filter circuit, a second output filter circuit, and a controller. The L1 line inverter circuit is connected to a battery and, via the first output filter circuit, is connected to a first load and the power grid. The L2 line inverter circuit is connected to the battery and, via the second output filter circuit, is connected to a second load. When the power grid is connected, the controller controls the L1 line inverter circuit to operate in current source mode and controls the L2 line inverter circuit to operate in voltage source mode. When the power grid fails, the controller controls both the L1 and L2 line inverter circuits to operate in voltage source mode. Therefore, the grid voltage and the L2 line inverter circuit are decoupled, and the output voltage of the L2 line inverter circuit is not affected by power outages, reducing the risk of power failure.

Description

Technical Field

[0001] This application relates to the field of inverter power supplies, and in particular to a split-phase inverter power supply system, control method, and controller. Background Technology

[0002] The inverter has the ability to switch between grid-connected and off-grid modes. When the grid is normal, the inverter operates in grid-connected mode, cooperating with the grid to supply power and charge the energy storage device. The grid also supplies power to the load. When the grid fails, it needs to switch to off-grid mode, and the energy storage device supplies power to the load independently.

[0003] Traditional grid-connected / off-grid switching technology typically detects grid outages and performs the switching action accordingly. When the grid loses power, due to the software detection time and the grid connection switch action time, the load port usually experiences a power outage of about 20 milliseconds, posing a risk of power failure to critical loads such as precision instruments. Summary of the Invention

[0004] The embodiments of this application aim to provide a split-phase inverter power supply system, control method and controller, which can continuously supply power to the load when the grid fails, thereby reducing the risk of power outage to the load.

[0005] To address the aforementioned technical problems, this application provides the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a split-phase inverter power supply system, the split-phase inverter power supply system including an L1 line inverter circuit, an L2 line inverter circuit, a first output filter circuit, a second output filter circuit, and a controller;

[0007] The input terminal of the L1 line inverter circuit is connected to the battery, the output terminal of the L1 line inverter circuit is connected to the input terminal of the first output filter circuit, the output terminal of the first output filter circuit is connected to the first load and the power grid respectively, and the control terminal of the L1 line inverter circuit is connected to the controller.

[0008] The input terminal of the L2 line inverter circuit is connected to the battery, the output terminal of the L2 line inverter circuit is connected to the input terminal of the second output filter circuit, the output terminal of the second output filter circuit is connected to the second load, and the control terminal of the L2 line inverter circuit is connected to the controller.

[0009] The controller is configured to, when connected to the power grid, control the L1 line inverter circuit to operate in a current source state to output a first voltage to the first load, and control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load; it is also configured to, when the power grid fails, control the L1 line inverter circuit to operate in a voltage source state to output a third voltage to the first load, and control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load.

[0010] Wherein, the first voltage is determined by the grid voltage of the power grid, the third voltage is determined by the output voltage of the L1 line inverter circuit, and the second voltage is determined by the output voltage of the L2 line inverter circuit.

[0011] In some embodiments, the L1 line inverter circuit includes a first input filter unit and a first power conversion unit;

[0012] The first input filtering unit is connected to the input terminals of the battery and the first power conversion unit, respectively. The first input filtering unit is configured to filter the current output by the battery and output a first current.

[0013] The output terminal of the first power conversion unit is connected to the input terminal of the first output filter circuit, and the control terminal of the first power conversion unit is connected to the controller. The controller is configured to control the first power conversion unit to operate in a current source state when the power grid is connected, so as to output the first voltage to the first load based on the power grid voltage and the first current. It is also configured to control the first power conversion unit to operate in a voltage source state when the power grid is de-energized, so as to output the second voltage to the first load based on the first current.

[0014] In some embodiments, the L2 line inverter circuit includes a second input filter unit and a second power conversion unit;

[0015] The second input filtering unit is connected to the input terminals of the battery and the second power conversion unit, respectively. The second input filtering unit is configured to filter the current output by the battery and output a second current.

[0016] The output terminal of the second power conversion unit is connected to the input terminal of the second output filter circuit, and the control terminal of the second power conversion unit is connected to the controller. The controller is configured to control the second power conversion unit to operate in voltage source state when the power grid is connected or when the power grid is de-energized, so as to output the third voltage to the second load based on the second current.

[0017] In some embodiments, both the first power conversion unit and the second power conversion unit are T-type inverter bridges.

[0018] In some embodiments, the first output filter circuit includes a first inductor and a first capacitor, and the second output filter circuit includes a second inductor and a second capacitor.

[0019] One end of the first inductor is connected to the L1 line inverter circuit, and the other end of the first inductor is connected to one end of the first capacitor, the power grid and the first load, respectively.

[0020] One end of the second inductor is connected to the L2 line inverter circuit, and the other end of the second inductor is connected to one end of the second capacitor and the second load, respectively.

[0021] In some embodiments, it further includes: a grid-connected switching circuit;

[0022] One end of the grid-connected switch circuit is connected to the output terminal of the L1 line inverter circuit and the first load, respectively, and the other end of the grid-connected switch circuit is connected to the power grid. The grid-connected switch circuit is configured to control the connection state between the power grid and the first load.

[0023] In a second aspect, embodiments of this application provide a control method applied to the controller described above, the method comprising:

[0024] When the grid is connected, the L1 line inverter circuit is controlled to operate in the current source state to output a first voltage to the first load, and the L2 line inverter circuit is controlled to operate in the voltage source state to output a second voltage to the second load. The first voltage is determined by the grid voltage of the grid, and the second voltage is determined by the output voltage of the L2 line inverter circuit.

[0025] When the power grid fails, the L1 line inverter circuit is controlled to operate in voltage source mode to output a third voltage to the first load, and the L2 line inverter circuit is controlled to operate in voltage source mode to output a second voltage to the second load. The third voltage is determined by the output voltage of the L1 line inverter circuit.

[0026] In some embodiments, controlling the L1 line inverter circuit to operate in a current source state includes:

[0027] The dq-axis reference current is obtained by performing a DQ transformation on the reference current;

[0028] The inductor current flowing through the first output filter circuit is sampled to obtain the first sampled current;

[0029] The dq-axis sampling current is obtained by performing a DQ transformation on the sampled current;

[0030] The dq-axis current deviation is obtained by subtracting the dq-axis sampling current from the dq-axis reference current.

[0031] The voltage signal compensation amount is obtained by passing the dq axis current deviation through the current loop regulator, wherein the voltage signal compensation amount is the voltage signal in the dq axis coordinate system;

[0032] The voltage signal compensation amount is added to the dq-axis component of the grid voltage to obtain the corrected voltage reference signal;

[0033] The corrected voltage reference signal is subjected to DQ inverse transform to obtain the L1 line voltage reference signal;

[0034] The L1 line voltage reference signal is input to the PWM modulation module to generate and output a first PWM signal, wherein the first PWM signal is used to drive the L1 line inverter circuit.

[0035] In some embodiments, controlling the L1 line inverter circuit to operate in a voltage source state includes:

[0036] The output voltage of the L1 line inverter circuit is sampled to obtain the first voltage feedback signal;

[0037] A first current reference signal is obtained through a voltage loop regulator based on the first voltage reference signal and the first voltage feedback signal;

[0038] The inductor current flowing through the first output filter circuit is sampled to obtain the first sampled current;

[0039] A first voltage compensation signal is obtained through a current loop regulator based on the first sampled current and the first current reference signal.

[0040] The first voltage compensation signal, the first voltage reference signal, and the load current feedforward of the first load are added together to obtain the first voltage target signal;

[0041] The first voltage target signal is input into the PWM modulation module to generate and output a second PWM signal, wherein the second PWM signal is used to drive the L1 line inverter circuit.

[0042] In some embodiments, controlling the L2 line inverter circuit to operate in a voltage source state includes:

[0043] The output voltage of the L2 line inverter circuit is sampled to obtain the second voltage feedback signal;

[0044] The second current reference signal is obtained through a voltage loop regulator based on the second voltage reference signal and the second voltage feedback signal;

[0045] The inductor current flowing through the second output filter circuit is sampled to obtain the second sampled current;

[0046] A second voltage compensation signal is obtained through a current loop regulator based on the second sampled current and the second current reference signal.

[0047] The second voltage compensation signal, the second voltage reference signal, and the load current feedforward of the second load are added together to obtain the second voltage target signal;

[0048] The second voltage target signal is input into the PWM modulation module to generate and output a third PWM signal, wherein the third PWM signal is used to drive the L2 line inverter circuit.

[0049] In a third aspect, embodiments of this application provide a controller, the controller comprising:

[0050] At least one processor; and,

[0051] A non-volatile memory communicatively connected to the at least one processor, the non-volatile memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the control method as described above.

[0052] In various embodiments of this application, the split-phase inverter power supply system includes an L1 line inverter circuit, an L2 line inverter circuit, a first output filter circuit, a second output filter circuit, and a controller. The input terminal of the L1 line inverter circuit is connected to a battery, and its output terminal is connected to the input terminal of the first output filter circuit. The output terminal of the first output filter circuit is connected to a first load and the power grid. The control terminal of the L1 line inverter circuit is connected to the controller. The input terminal of the L2 line inverter circuit is connected to the battery, and its output terminal is connected to the input terminal of the second output filter circuit. The output terminal of the second output filter circuit is connected to a second load, and its control terminal is connected to the controller. When the power grid is connected, the controller controls the L1 line inverter circuit to operate in a current source state to output a first voltage to the first load, and controls the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load. When the power grid fails, the controller controls the L1 line inverter circuit to operate in voltage source mode to output a third voltage to the first load, and controls the L2 line inverter circuit to operate in voltage source mode to output a second voltage to the second load. The first voltage is determined by the grid voltage, the third voltage is determined by the output voltage of the L1 line inverter circuit, and the second voltage is determined by the output voltage of the L2 line inverter circuit.

[0053] Therefore, this split-phase inverter power supply system is equipped with two inverter circuits, and the L2 line inverter circuit is only connected to the battery. The battery voltage is output to the second load through the L2 line inverter circuit. The L2 line inverter circuit operates in voltage source mode to generate the second voltage. The second voltage is always determined by the output voltage of the L2 line inverter circuit and is independent of the grid voltage. This achieves decoupling control between the grid voltage and the second voltage. Therefore, when the grid fails, it does not affect the second voltage. The second voltage achieves seamless switching without a power outage process. During the grid-connected / off-grid switching process, the second load is controlled without power failure through the second voltage, reducing the risk of power outage. Attached Figure Description

[0054] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0055] Figure 1 This is a schematic diagram of the structure of one of the split-phase inverter power supply systems provided in the embodiments of this application;

[0056] Figure 2 This is a schematic diagram of the structure of one of the split-phase inverter power supply systems provided in the embodiments of this application;

[0057] Figure 3 This is a schematic diagram of the structure of one of the L1 line inverter circuits and L2 line inverter circuits provided in the embodiments of this application;

[0058] Figure 4 This is a schematic diagram of the circuit structure of one of the split-phase inverter power supply systems provided in the embodiments of this application;

[0059] Figure 5 This is a flowchart illustrating one of the control methods provided in the embodiments of this application;

[0060] Figure 6 yes Figure 5 A flowchart illustrating step S10;

[0061] Figure 7 This is a schematic diagram of one of the control models provided in the embodiments of this application;

[0062] Figure 8 yes Figure 5 A flowchart illustrating step S10;

[0063] Figure 9 This is a schematic diagram of one of the control models provided in the embodiments of this application;

[0064] Figure 10 yes Figure 5A flowchart illustrating step S20;

[0065] Figure 11 This is a timing diagram showing the amplitudes of the grid voltage, grid online indicator, output voltage of the L1 line inverter circuit, and output voltage of the L2 line inverter circuit, as provided in one embodiment of this application.

[0066] Figure 12 This is a schematic diagram of the structure of one of the control devices provided in the embodiments of this application;

[0067] Figure 13 This is a schematic diagram of the hardware structure of one of the controllers provided in the embodiments of this application. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0069] Please see Figure 1 This application provides a schematic diagram of the structure of a split-phase inverter power supply system, as shown in the embodiment. Figure 1 As shown, the split-phase inverter power supply system 100 includes an L1 line inverter circuit 10, an L2 line inverter circuit 20, a first output filter circuit 30, a second output filter circuit 40, and a controller 50. The input terminal of the L1 line inverter circuit 10 is connected to the battery 200, and its output terminal is connected to the input terminal of the first output filter circuit 30. The output terminal of the first output filter circuit 30 is connected to a first load and the power grid, respectively. The control terminal of the L1 line inverter circuit 10 is connected to the controller 50. The input terminal of the L2 line inverter circuit 20 is connected to the battery 200, and its output terminal is connected to the input terminal of the second output filter circuit 40. The output terminal of the second output filter circuit 40 is connected to a second load, and the control terminal of the L2 line inverter circuit 20 is connected to the controller 50.

[0070] In some embodiments, the split-phase inverter power supply system 100 includes a grid-connected switch circuit 60, one end of which is connected to the output terminal of the L1 line inverter circuit 10 and the first load, and the other end of which is connected to the power grid.

[0071] When the amplitude, frequency, and phase of the output voltage of the L1 line inverter circuit 10 are precisely matched with the grid parameters, for example, with an error within ±1%, the controller 50 controls the grid-connected switch circuit 60 to turn on, smoothly connecting to the grid and completing the grid connection. In some embodiments, the controller 50 controls the grid-connected switch circuit 60 to turn off, simulating a power outage. Thus, the grid-connected switch circuit 60 controls the connection state between the grid and the first load.

[0072] The grid-connected switch circuit 60 can be any switch that meets the requirements, such as a contactor or a relay.

[0073] When the grid is connected, the controller 50 controls the L1 line inverter circuit 10 to operate in current source mode, i.e., in grid-connected mode. Specifically, if the grid supply is sufficient, the controller 50 controls the L1 line inverter circuit 10 to output a stable and controllable current. The amplitude and phase of the output current are determined by the controller 50 and kept synchronized with the grid voltage. The controller 50 uses current loop control. By detecting the deviation between the output current of the L1 line inverter circuit 10 and the command current, a modulation signal is output through a regulator (such as a PI regulator) to control the PWM pulse width, ultimately making the actual output current track the command current. At the same time, the controller 50 detects the phase of the grid voltage in real time through a phase-locked loop (PLL) to ensure that the phase of the output current of the L1 line inverter circuit 10 is consistent with the phase of the grid voltage (active power transmission) or has a fixed phase difference (reactive power transmission).

[0074] When the L1 line inverter circuit 10 is connected to the power grid and operates in current source mode, the power grid provides a stable voltage reference (such as the rated phase voltage) to ensure that the first voltage across the first load is maintained within the normal range. The L1 line inverter circuit 10 outputs an active current in phase with the grid voltage (or outputs a current of a specific phase according to the reactive power demand of the load) through current loop control. This current, together with the current provided by the grid, constitutes the total current required by the first load.

[0075] When the load power changes, the L1 line inverter circuit 10 quickly adjusts the output current amplitude to compensate for the insufficient or redundant grid current, ensuring the stability of the first load current, thereby achieving continuous power supply to the first load, and the power supply quality is not significantly affected by the instantaneous fluctuations of the grid.

[0076] While meeting the power supply needs of the first load, the power grid can also charge the battery 200 through the L1 line inverter circuit 10. The system coordinates the power consumption and charging needs of the first load through a power distribution mechanism. Under the premise of ensuring normal power supply to the first load, the controller 50 generates a charging current command based on the SOC state of the battery 200 and outputs a corresponding PWM signal based on the charging current command. This PWM signal drives the L1 line inverter circuit 10, causing the L1 line inverter circuit 10 to adjust the active component in the output current, absorbing additional active power from the power grid and converting it into DC current through an internal rectification stage.

[0077] The DC current is transmitted to the battery 200 according to a preset charging strategy (such as constant current or constant voltage mode). At the same time, the charging current and the status of the battery 200 are monitored in real time through closed-loop feedback, and the active current output of the L1 line inverter circuit 10 is dynamically adjusted to ensure that the charging process is safe and efficient, and does not affect the normal power supply to the first load.

[0078] Meanwhile, the L2 line inverter circuit 20 is only connected to the battery 200. When the grid is connected, the L2 line inverter circuit 20 operates in inverter mode, converting the DC power output from the battery 200 into AC power to supply power to the second load.

[0079] Specifically, the controller 50 controls the L2 line inverter circuit 20 to operate in voltage source mode to output a second voltage to the second load. The L2 line inverter circuit 20 removes ripple interference from the DC power output by the battery 200, then chops the filtered DC power into pulsed AC power, and then filters out high-frequency harmonics in the pulsed AC power, finally forming a sinusoidal second voltage output to the second load.

[0080] The controller 50 uses PWM pulse signals to drive the power switching transistors in the L2 line inverter circuit 20 to turn on and off according to specific logic, thereby chopping the filtered DC power into pulsed AC power. The controller 50 uses an outer voltage loop and an inner current loop control to generate the PWM pulse signal, enabling the L2 line inverter circuit 20 to output a stable voltage. For example, the controller 50 compares the actual value of the second voltage with a preset voltage reference value to obtain a voltage deviation. This voltage deviation is processed by a voltage loop regulator (such as a PI regulator) to generate a current reference value. The current reference value is then compared with the actual current flowing through the L2 line inverter circuit 20 to generate a current deviation. This current deviation is processed by a current loop regulator (such as a P regulator) to generate a target current value, and then a corresponding PWM pulse signal is generated based on the target current value. In some embodiments, feedforward control can also be performed based on the target current value to generate the corresponding PWM pulse signal again.

[0081] Therefore, the power supply of the second load depends entirely on the energy conversion of the battery 200. The L2 line inverter circuit 20 serves as a voltage source, and its output voltage directly determines the amplitude, frequency, and waveform of the second voltage, ensuring that the second load receives sinusoidal AC power that meets the rated parameters.

[0082] When the power grid fails, the controller 50 controls the L1 line inverter circuit 10 to operate in voltage source mode, converting the DC power output from the battery 200 into AC power, and outputting a third voltage to the first load. The third voltage is determined by the output voltage of the L1 line inverter circuit 10.

[0083] Meanwhile, the L2 line inverter circuit 20 continues to operate in voltage source mode, converting the DC power output from the battery 200 into AC power, and continuing to output a second voltage to the second load. The second voltage is still determined by the output voltage of the L2 line inverter circuit 20.

[0084] Therefore, when the power grid fails, the operating state of the L1 line inverter circuit 10 changes, and the power supply for the first load switches from the power grid to the battery 200. During this switching process, the first load experiences a power outage, the duration of which is determined by the switching time. However, the operating state of the L2 line inverter circuit 20 remains unchanged; the power supply for the second load remains with the battery 200. During this switching process, the second load does not experience a power outage, and the power grid failure does not affect its power supply. This achieves seamless switching for the second load, reducing the risk of power outages.

[0085] In related technologies, for split-phase systems, both the L1 line inverter circuit 10 and the L2 line inverter circuit 20 are connected to the power grid. The first load is connected to one phase of the power grid, and the second load is connected to another phase of the power grid. Therefore, when the power grid fails or when switching between grid connection and disconnection, both the first load and the second load will experience power loss, posing a risk of power loss.

[0086] In this embodiment, two inverter circuits are set up, and the L2 line inverter circuit 20 is not connected to the power grid. It is only connected to the battery 200. The battery 200 realizes the decoupling control between the grid voltage and the output voltage of the L2 line inverter circuit 20. The second voltage is always output by the L2 inverter circuit 20. When the grid loses power or switches between grid connection and disconnection, the output voltage of the L2 line inverter circuit 20 switches seamlessly, and the second load will not lose power, reducing the risk of power failure.

[0087] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of a split-phase inverter power supply system provided in an embodiment of this application, as shown below. Figure 2 As shown, the L1 line inverter circuit 10 includes a first input filter unit 11 and a first power conversion unit 12. The first input filter unit 11 is connected to the battery 200 and the input terminal of the first power conversion unit 12, respectively. The output terminal of the first power conversion unit 12 is connected to the input terminal of the first output filter circuit 30. The control terminal of the first power conversion unit 12 is connected to the controller 50.

[0088] When the power grid is connected, the first input filter unit 11 filters the current output by the battery 200 and outputs the first current. The controller 50 controls the first power conversion unit 12 to operate in the current source state so as to output the first voltage to the first load based on the grid voltage and the first current.

[0089] If the grid voltage can fully meet the power supply requirements of the first load, the first voltage is entirely determined by the grid voltage, and the grid can also charge the battery 200 via the L1 line inverter circuit 10. If the power supply requirements of the first load increase and the grid voltage cannot meet the power supply requirements of the first load, the battery 200 and the grid will jointly supply power to the first load. The first input filter unit 11 filters the current output by the battery 200 and outputs the first current. The controller 50 controls the first power conversion unit 12 to operate in the current source state, converts the first current into AC current, and outputs it together with the current provided by the grid to the first load to output the first voltage to the first load.

[0090] When the power grid fails, the controller 50 controls the first power conversion unit 12 to operate in voltage source mode, so as to output a second voltage to the first load based on the first current. At this time, the second voltage is entirely determined by the voltage output by the battery 200.

[0091] In some embodiments, the L2 line inverter circuit 20 includes a second input filter unit 21 and a second power conversion unit 22, wherein the second input filter unit 21 is connected to the input terminals of the battery 200 and the second power conversion unit 22, respectively, the output terminal of the second power conversion unit 22 is connected to the input terminal of the second output filter circuit 40, and the control terminal of the second power conversion unit 22 is connected to the controller 50.

[0092] The L2 line inverter circuit 20 is not connected to the power grid, but only to the battery 200. When the power grid is connected or the power grid is lost, the second input filter unit 21 filters the current output by the battery 200 and outputs a second current. The controller 50 controls the second power conversion unit 22 to operate in voltage source mode so as to output a third voltage to the second load based on the second current.

[0093] Therefore, regardless of whether the grid is connected or the grid is de-energized, the third voltage is determined by the output voltage of the storage battery 200, and the storage battery 200 provides power to the second load only, so the second load will not experience a power outage.

[0094] In this embodiment, both the L1 line inverter circuit 10 and the L2 line inverter circuit 20 are T-type inverter bridges. Figure 3As shown, the first input filter unit 11 is the positive bus capacitor BUS+, the second input filter unit 21 is the negative bus capacitor BUS-, and the first power conversion unit 12 includes MOSFETs Q1, Q2, Q5, and Q6. MOSFETs Q1 and Q2 are connected in series, and the source of MOSFET Q1 is connected to one end of the positive bus capacitor BUS+. The source of MOSFET Q2 is connected to one end of the negative bus capacitor BUS-. The source of MOSFET Q5 is connected to the source of MOSFET Q6. The drain of MOSFET Q5 is grounded, and the drain of MOSFET Q6 is connected to the first output filter circuit 30.

[0095] The second power conversion unit 22 includes MOSFETs Q3, Q4, Q7, and Q8. MOSFETs Q3 and Q4 are connected in series, and the source of MOSFET Q3 is connected to one end of the positive bus capacitor BUS+. The source of MOSFET Q4 is connected to one end of the negative bus capacitor BUS-. The sources of MOSFET Q7 and Q8 are connected. The drain of MOSFET Q7 is grounded, and the drain of MOSFET Q8 is connected to the second output filter circuit 40.

[0096] The working process of the first power conversion unit 12 and the second power conversion unit 22 can be described as follows:

[0097] Phase splitting wave generation timing:

[0098] L1 line control:

[0099] MOSFETs Q1 and Q5 are configured for high-frequency complementary operation and are responsible for sinusoidal wave generation. MOSFETs Q2 and Q6 are configured for power frequency complementary operation and are responsible for power frequency switching.

[0100] Positive half-wave control timing: MOSFET Q2 is turned off and MOSFET Q6 is turned on. The voltage of the first power conversion unit is controlled by the positive bus capacitor BUS+. MOSFETs Q1 and Q5 generate PWM waves to control the instantaneous voltage output by the first power conversion unit.

[0101] Negative half-wave control timing: MOSFET Q1 is turned off and MOSFET Q5 is turned on. The voltage of the first power conversion unit is controlled by the negative bus capacitor BUS-. MOSFETs Q2 and Q6 generate PWM waves to control the instantaneous voltage output by the first power conversion unit.

[0102] L2 line control:

[0103] MOSFETs Q3 and Q7 are configured for high-frequency complementary operation and are responsible for sinusoidal wave generation. MOSFETs Q4 and Q8 are configured for power frequency complementary operation and are responsible for power frequency switching.

[0104] Positive half-wave control timing: MOSFET Q4 is turned off and MOSFET Q8 is turned on. The voltage of the second power conversion unit is controlled by the positive bus capacitor BUS+. MOSFETs Q3 and Q7 generate PWM waves to control the instantaneous voltage output from line L2.

[0105] Negative half-wave control timing: MOSFET Q3 is turned off and MOSFET Q7 is turned on. The voltage of the second power conversion unit is controlled by the negative bus capacitor BUS-. MOSFETs Q4 and Q8 generate PWM waves to control the instantaneous voltage output by the second power conversion unit.

[0106] Phase splitting cycle synchronization:

[0107] When the grid frequency changes, the power frequency of the first power conversion unit needs to follow the grid frequency and also synchronize the frequency to the second power conversion unit. That is, the power frequency waves of MOSFETs Q2 and Q6, and MOSFETs Q4 and Q8 need to be consistent. Otherwise, a phase shift will occur, and the line voltage output by the first power conversion unit and the line voltage output by the second power conversion unit will not be constant.

[0108] When the grid voltage changes, the control peak voltage of the first power conversion unit needs to follow the grid voltage and also synchronize the voltage to the second power conversion unit. That is, the peak voltages controlled by MOSFETs Q1 and Q5, and MOSFETs Q3 and Q7 need to be consistent. Otherwise, the voltage output by the first power conversion unit will be unbalanced with the voltage output by the second power conversion unit.

[0109] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of a split-phase inverter power supply system provided in an embodiment of this application, as shown below. Figure 4 As shown, the first output filter circuit 30 includes a first inductor L1 and a first capacitor C1, and the second output filter circuit 40 includes a second inductor L2 and a second capacitor C2. One end of the first inductor L1 is connected to the L1 line inverter circuit 10, and the other end of the first inductor L1 is connected to one end of the first capacitor C1, the power grid, and the first load. One end of the second inductor L2 is connected to the L2 line inverter circuit 20, and the other end of the second inductor L2 is connected to one end of the second capacitor C2 and the second load.

[0110] In this embodiment, the grid-connected switch circuit 60 is a relay, the storage battery 200 is a battery bus, and the first power conversion unit 12 and the second power conversion unit 22 are both T-type inverter bridges.

[0111] The first inductor L1 and the first capacitor C1 form a low-pass filter to filter the first current output by the L1 line inverter circuit 10, removing high-frequency harmonics. Similarly, the second inductor L2 and the second capacitor C2 form a low-pass filter to filter the first current output by the L1 line inverter circuit 10, removing high-frequency harmonics.

[0112] In summary, this split-phase inverter power supply system is equipped with two inverter circuits, and the L2 line inverter circuit is only connected to the battery. The battery voltage is output to the second load through the L2 line inverter circuit. The second voltage is always determined by the output voltage of the L2 line inverter circuit and is independent of the grid voltage. This achieves decoupling control between the grid voltage and the second voltage. Therefore, when the grid fails, it does not affect the second voltage. The second voltage achieves seamless switching without a power outage process. Thus, during the grid-connected / off-grid switching process, the second voltage enables uninterrupted power control of the second load, reducing the risk of power outage.

[0113] It should be noted that the "connection" in the embodiments of this application refers to an electrical connection. An electrical connection is a connection method that uses a conductor or conductive medium to connect electrical equipment, components, circuits, etc., to form a closed loop that allows current to flow, so as to realize power transmission, signal transmission, or circuit function.

[0114] As another aspect of the embodiments of this application, the following embodiments of this application provide a control method applied to the controller described in the above embodiments. The controller is applied to a split-phase inverter power supply system, and the split-phase inverter power supply system includes an L1 line inverter circuit, an L2 line inverter circuit, a first output filter circuit, a second output filter circuit, and a controller. The specific structure and connection relationships of the split-phase inverter power supply system are as follows: Figure 1 As shown. Please refer to [the original text]. Figure 5 , Figure 5 This application provides a control method, the power control method S100 including:

[0115] S10: When the grid is connected, the L1 line inverter circuit is controlled to operate in the current source state to output a first voltage to the first load, and the L2 line inverter circuit is controlled to operate in the voltage source state to output a second voltage to the second load. The first voltage is determined by the grid voltage of the grid, and the second voltage is determined by the output voltage of the L2 line inverter circuit.

[0116] When the grid is connected, the L1 line inverter circuit is connected to the grid, and the power supply for the first load is provided by the grid. The controller controls the L1 line inverter circuit to operate in the current source state. Specifically, it controls the switching transistor of the first power conversion unit in the L1 line inverter circuit, using current loop control to generate a corresponding PWM signal to control the on and off of the switching transistor of the first power conversion unit, so as to output a stable current to the first load.

[0117] like Figure 6 As shown, step S10 includes:

[0118] S101: Perform DQ transformation on the reference current to obtain the dq-axis reference current;

[0119] S102: Sample the inductor current flowing through the first output filter circuit to obtain the first sampled current;

[0120] S103: Perform DQ transformation on the sampled current to obtain the dq axis sampled current;

[0121] S104: Subtract the dq-axis sampling current from the dq-axis reference current to obtain the dq-axis current deviation;

[0122] S105: The voltage signal compensation amount is obtained by passing the dq axis current deviation through the current loop regulator, wherein the voltage signal compensation amount is the voltage signal in the dq axis coordinate system;

[0123] S106: Add the voltage signal compensation amount to the dq-axis component of the grid voltage to obtain the corrected voltage reference signal;

[0124] S107: Perform DQ inverse transformation on the corrected voltage reference signal to obtain the L1 line voltage reference signal;

[0125] S108: Input the L1 line voltage reference signal into the PWM modulation module to generate and output a first PWM signal, wherein the first PWM signal is used to drive the L1 line inverter circuit.

[0126] Specifically, please refer to Figure 7 , Figure 7 This is a schematic diagram of a control model provided in an embodiment of this application. For example... Figure 7 The lower half, as shown, first determines the reference current. Reference current After DQ conversion, the d-axis reference current is obtained. With q-axis reference current The current flowing through the first inductor is sampled to obtain the first sampled current. First sampling current The d-axis sampling current is obtained through the DQ variation. With q-axis sampling current Set the d-axis reference current. Subtract d-axis sampling current The d-axis current deviation is obtained, and the q-axis reference current is used. Subtract q-axis sampling current The q-axis current deviation is obtained. Then, the d-axis current deviation is passed through a current loop regulator (PI regulator) to obtain the d-axis voltage signal compensation amount, and the q-axis current deviation is passed through a current loop regulator (PI regulator) to obtain the q-axis voltage signal compensation amount.

[0127] Then the grid voltage Perform DQ conversion to obtain the d-axis component of the grid voltage. With q-axis components The d-axis voltage signal compensation amount is compared with the d-axis component of the grid voltage. Adding them together yields the d-axis corrected voltage reference signal. The q-axis voltage signal compensation is then added to the q-axis component of the grid voltage. The q-axis corrected voltage reference signal is obtained by adding the two signals together. Finally, the d-axis corrected voltage reference signal and the q-axis corrected voltage reference signal are subjected to inverse DQ transform to obtain the L1 line voltage reference signal. The PWM modulation module generates and outputs the first PWM signal based on the L1 line voltage reference signal. The L1 line voltage reference signal determines the duty cycle of the first PWM signal, which in turn determines the magnitude of the current output to the first load.

[0128] When the grid is connected, the L2 line inverter circuit is only connected to the battery. The power supply for the second load is provided by the battery. The controller controls the L2 line inverter circuit to operate in voltage source mode. Specifically, it controls the switching transistors of the second power conversion unit in the L2 line inverter circuit. The voltage loop and current loop are used for joint control to generate corresponding PWM signals, which control the switching transistors of the second power conversion unit to turn on and off, so as to output a stable voltage to the second load.

[0129] like Figure 8 As shown, step S10 further includes:

[0130] S109: Sample the output voltage of the L2 line inverter circuit to obtain a second voltage feedback signal;

[0131] S110: A second current reference signal is obtained through a voltage loop regulator based on the second voltage reference signal and the second voltage feedback signal;

[0132] First, the second voltage reference signal is subtracted from the second voltage feedback signal to obtain the second voltage deviation signal. Then, the second voltage deviation signal is passed through the voltage loop regulator to obtain the second current reference signal.

[0133] S111: Sample the inductor current flowing through the second output filter circuit to obtain the second sampled current;

[0134] S112: A second voltage compensation signal is obtained through a current loop regulator based on the second sampled current and the second current reference signal;

[0135] First, the second current reference signal is subtracted from the second sampling current to obtain the second current deviation signal. Then, the second current deviation signal is passed through the current loop regulator to obtain the second voltage compensation signal.

[0136] S113: The second voltage compensation signal, the second voltage reference signal, and the load current feedforward of the second load are added together to obtain the second voltage target signal;

[0137] S114: Input the second voltage target signal into the PWM modulation module to generate and output a third PWM signal, wherein the third PWM signal is used to drive the L2 line inverter circuit.

[0138] Specifically, please refer to Figure 9 , Figure 9 This is a schematic diagram of a control model provided in an embodiment of this application, such as... Figure 9 As shown, the output voltage of the L2 line inverter circuit is first sampled to obtain the second voltage feedback signal. Then determine the second voltage reference amplitude. Taking a rated voltage of 120V as an example, the second voltage reference amplitude Second voltage reference amplitude Multiply by a sine wave Obtain the second voltage reference signal of the voltage loop. Then the second voltage reference signal With the second voltage feedback signal The second voltage deviation signal is obtained by subtraction. This second voltage deviation signal is then passed through a voltage loop regulator (PI regulator) to obtain the second current reference value. The second current reference value is then multiplied by a sine wave signal. Obtain the second current reference signal .

[0139] Second current reference signal The expression is:

[0140] (1)

[0141] in, This is the proportional gain of the voltage loop regulator. This is the integral coefficient of the voltage loop regulator.

[0142] The inductor current flowing through the second inductor is sampled to obtain the second sampled current. The second current reference signal Subtract the second sampling current The second current deviation signal is obtained, and then the second current deviation signal is passed through the current loop regulator (P regulation) to obtain the second voltage compensation signal. ΔU 2. The second voltage compensation signal ΔU 2. Second voltage reference signal and the load current feedforward of the second load The second voltage target signal is obtained by adding them together. .

[0143] Second voltage target signal The expression is:

[0144] (2)

[0145] in, This is the proportional coefficient of the current loop regulator.

[0146] Finally, the second voltage target signal The input PWM modulation module generates and outputs a third PWM signal, where the second PWM signal is used to drive the L2 line inverter circuit.

[0147] Furthermore, the control model uses a programmable switch to represent the grid connection flag. When the grid is connected, the programmable switch is in the first state, connecting the current source control model to the PWM modulation module to generate the first PWM signal. When the grid is de-energized, the programmable switch is in the second state, connecting the voltage source control model to the PWM modulation module to generate the second PWM signal.

[0148] S20: When the power grid fails, control the L1 line inverter circuit to operate in voltage source mode to output a third voltage to the first load, and control the L2 line inverter circuit to operate in voltage source mode to output a second voltage to the second load. The third voltage is determined by the output voltage of the L1 line inverter circuit.

[0149] When the power grid fails, the operating state of the L1 line inverter circuit changes, and the power supply to the first load is switched to the battery. The controller controls the L1 line inverter circuit to operate in voltage source mode. Specifically, it controls the switching transistor of the first power conversion unit in the L1 line inverter circuit, using voltage loop and current loop control to generate corresponding PWM signals to control the on and off of the switching transistor of the first power conversion unit, so as to output a stable voltage to the first load.

[0150] like Figure 10 As shown, step S20 includes:

[0151] S201: Sample the output voltage of the L1 line inverter circuit to obtain the first voltage feedback signal;

[0152] S202: A first current reference signal is obtained through a voltage loop regulator based on the first voltage reference signal and the first voltage feedback signal;

[0153] The first voltage deviation signal is obtained by subtracting the first voltage feedback signal from the first voltage reference signal, and then the first voltage deviation signal is passed through the voltage loop regulator to obtain the first current reference signal.

[0154] S203: Sample the inductor current flowing through the first output filter circuit to obtain the first sampled current;

[0155] S204: Based on the first sampled current and the first current reference signal, a first voltage compensation signal is obtained through a current loop regulator;

[0156] The first current deviation signal is obtained by subtracting the first sampling current from the first current reference signal, and the first current deviation signal is then passed through the current loop regulator to obtain the first voltage compensation signal.

[0157] S205: The first voltage compensation signal, the first voltage reference signal, and the load current feedforward of the first load are added together to obtain the first voltage target signal;

[0158] S206: Input the first voltage target signal into the PWM modulation module to generate and output a second PWM signal, wherein the second PWM signal is used to drive the L1 line inverter circuit.

[0159] For details, please continue reading Figure 7 ,like Figure 7 As shown, the output voltage of the L1 line inverter circuit is first sampled to obtain the first voltage feedback signal. Then determine the first voltage reference amplitude. Taking a rated voltage of 120V as an example, the first voltage reference amplitude First voltage reference amplitude Multiply by a sine wave Obtain the first voltage reference signal of the voltage loop. Then, the first voltage reference signal and the first voltage feedback signal are combined. The first voltage deviation signal is obtained by subtraction. This first voltage deviation signal is then passed through a voltage loop regulator (PI regulator) to obtain the first current reference value. The first current reference value is then multiplied by a sine wave signal. Obtain the first current reference signal .

[0160] First current reference signal The expression is:

[0161] (3)

[0162] in, This is the proportional gain of the voltage loop regulator. This is the integral coefficient of the voltage loop regulator.

[0163] The inductor current flowing through the first inductor is sampled to obtain the first sampled current. The first current reference signal Subtract the first sampling current The first current deviation signal is obtained, and then the first current deviation signal is passed through the current loop regulator (P regulation) to obtain the first voltage compensation signal. ΔU 1.

[0164] The first voltage compensation signal ΔU 1. First voltage reference signal and the load current feedforward of the first load The first voltage target signal is obtained by adding them together. .

[0165] First voltage target signal The expression is:

[0166] (4)

[0167] in, This is the proportional coefficient of the current loop regulator.

[0168] Finally, the first voltage target signal The input PWM modulation module generates and outputs a second PWM signal, which is used to drive the L1 line inverter circuit.

[0169] Therefore, when the grid is connected, a first PWM signal is generated through current loop control. This first PWM signal drives the L1 line inverter circuit to operate in current source mode. A third PWM signal is generated through voltage loop control and current loop control, and this third PWM signal drives the L2 line inverter circuit to operate in voltage source mode. When the grid is de-energized, a second PWM signal is generated through voltage loop control and current loop control. This second PWM signal drives the L1 line inverter circuit to operate in voltage source mode, and simultaneously generates a third PWM signal, which continues to drive the L2 line inverter circuit to operate in voltage source mode.

[0170] By using the above control method, the following can be obtained: Figure 11 The timing diagram shown depicts the grid voltage, grid online indicator, output voltage of line L1 inverter circuit, and output voltage amplitude of line L2 inverter circuit. Before the grid power failure, the grid online indicator amplitude remains at a value greater than zero, and the output voltage U of line L1 inverter circuit... O1 The L2 inverter circuit converts the DC power output from the battery into AC power, using the grid voltage to supply power to the first load. This results in the output voltage U of the L2 inverter circuit. O2 It is independent of the grid voltage and is not affected by the grid voltage.

[0171] When the power grid fails, the output voltage U of the L1 line inverter circuit... O1 The voltage is zero, indicating a power outage at the first load. The output voltage U of the inverter circuit on line L2 is zero. O2 Maintaining the same operating state, at the moment the software determines a power outage, the L1 line inverter circuit completes the conversion, converting the DC power from the battery to AC power, resulting in the output voltage U of the L1 line inverter circuit. O1 Its output voltage is determined by the battery's output voltage, while the output voltage U of the L2 line inverter circuit is... O2 It remains unchanged.

[0172] Therefore, when the power grid fails, the L1 line inverter circuit switches from a current source state to a voltage source state, and during the transition, the output voltage U of the L1 line inverter circuit... O1 During a power outage, the first load is at risk of losing power, while the L2 line inverter circuit remains in a voltage source state. The output voltage U of the L2 line inverter circuit... O2 No power outage occurred, the second load is not at risk of power failure, and the output voltage U of the L2 line inverter circuit is [value missing]. O2 By decoupling control from the grid voltage, the L2 line inverter circuit achieves seamless switching, reducing the risk of power failure of the second load.

[0173] It should be noted that in the above embodiments, there is no necessarily a certain order between the steps. Those skilled in the art can understand from the description of the embodiments of this application that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in turn, etc.

[0174] As another aspect of the embodiments of this application, this application provides a control device applied to the controller described above. The control device can be a software module, which includes several instructions stored in a memory. A processor can access the memory, invoke the instructions, and execute them to complete the control methods described in the various embodiments above.

[0175] In some embodiments, the control device can also be constructed from hardware components. For example, the control device can be constructed from one or more chips, which can work in coordination to complete the control methods described in the various embodiments above. As another example, the control device can also be constructed from various logic devices, such as general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microcontrollers, ARM (Acorn RISC Machine) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of these components.

[0176] Please see Figure 12 , Figure 12 This is a schematic diagram of the structure of a control device provided in an embodiment of this application, such as... Figure 12 As shown, the control device 300 includes a first control module 301 and a second control module 302.

[0177] The first control module 301 is used to control the L1 line inverter circuit to operate in a current source state to output a first voltage to the first load and to control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load when the grid is connected. The first voltage is determined by the grid voltage and the second voltage is determined by the output voltage of the L2 line inverter circuit. The second control module 302 is used to control the L1 line inverter circuit to operate in a voltage source state to output a third voltage to the first load and to control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load when the grid is disconnected. The third voltage is determined by the output voltage of the L1 line inverter circuit.

[0178] It should be noted that since the control device and the control method in the above embodiments are based on the same inventive concept, the corresponding contents in the above method embodiments are also applicable to the device embodiments, and will not be described in detail here.

[0179] In summary, this control device controls the L2 line inverter circuit to operate in a voltage source state to generate a second voltage. The second voltage is always determined by the output voltage of the L2 line inverter circuit and is independent of the grid voltage. This achieves decoupling control between the grid voltage and the second voltage. Therefore, when the grid loses power, it does not affect the second voltage. The second voltage achieves seamless switching without any power outage process. Thus, during the grid-connected / off-grid switching process, the second voltage enables uninterrupted power control of the second load, reducing the risk of power outage.

[0180] Please see Figure 13 , Figure 13 This is a schematic diagram of the structure of a controller provided in an embodiment of this application. Figure 13 As shown, the controller 50 includes one or more processors 501 and a memory 502. Wherein, Figure 13 Take a processor 501 as an example.

[0181] The processor 501 and the memory 502 can be connected via a bus or other means. Figure 13 Taking the example of a connection between China and Israel via a bus.

[0182] The memory 502, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the control device in the embodiments of this application. The processor 501 executes various functional applications and data processing of the control device by running the non-volatile software programs, instructions, and modules stored in the memory 502, thereby realizing the control method provided in the above method embodiments and the functions of various modules or units in the above device embodiments.

[0183] Memory 502 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 502 may optionally include memory remotely located relative to processor 501, and these remote memories may be connected to processor 501 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0184] The program instructions / modules are stored in the memory 502 and, when executed by one or more processors 501, execute the control method in any of the above method embodiments.

[0185] This application also provides a non-transitory computer-readable storage medium storing computer-executable instructions that are executed by one or more processors, for example... Figure 13 One of the processors 501 can enable the one or more processors to execute the control method in any of the above method embodiments.

[0186] This application also provides a non-volatile computer storage medium storing computer-executable instructions that are executed by one or more processors, for example... Figure 13 One of the processors 501 can enable the one or more processors to execute the control method in any of the above method embodiments.

[0187] This application also provides a computer program product, which includes a computer program stored on a non-volatile computer-readable storage medium. The computer program includes program instructions that, when executed by a controller, cause the controller to perform any of the control methods described above.

[0188] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software and a general-purpose hardware platform, or of course, using hardware. Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program in a computer program product instructing related hardware. The computer program can be stored in a non-transitory computer-readable storage medium. The computer program includes program instructions, which, when executed by the UAV, cause the UAV to execute the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0189] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A split-phase inverter power supply system, characterized in that, The split-phase inverter power supply system includes an L1 line inverter circuit, an L2 line inverter circuit, a first output filter circuit, a second output filter circuit, and a controller. The input terminal of the L1 line inverter circuit is connected to the battery, the output terminal of the L1 line inverter circuit is connected to the input terminal of the first output filter circuit, the output terminal of the first output filter circuit is connected to the first load and the power grid respectively, and the control terminal of the L1 line inverter circuit is connected to the controller. The input terminal of the L2 line inverter circuit is connected to the battery, the output terminal of the L2 line inverter circuit is connected to the input terminal of the second output filter circuit, the output terminal of the second output filter circuit is connected to the second load, and the control terminal of the L2 line inverter circuit is connected to the controller. The controller is configured to, when connected to the power grid, control the L1 line inverter circuit to operate in a current source state to output a first voltage to the first load, and control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load; it is also configured to, when the power grid fails, control the L1 line inverter circuit to operate in a voltage source state to output a third voltage to the first load, and control the L2 line inverter circuit to operate in a voltage source state to output a second voltage to the second load. Wherein, the first voltage is determined by the grid voltage of the power grid, the third voltage is determined by the output voltage of the L1 line inverter circuit, and the second voltage is determined by the output voltage of the L2 line inverter circuit; The control of the L2 line inverter circuit to operate in voltage source mode includes: The output voltage of the L2 line inverter circuit is sampled to obtain the second voltage feedback signal; The second voltage deviation signal is obtained by subtracting the second voltage feedback signal from the second voltage reference signal, and then the second current reference signal is obtained by passing it through the voltage loop regulator; The inductor current flowing through the second output filter circuit is sampled to obtain the second sampled current; The second current deviation signal is obtained by subtracting the second sampling current from the second current reference signal, and then the second voltage compensation signal is obtained by passing it through the current loop regulator. The second voltage compensation signal, the second voltage reference signal, and the load current feedforward of the second load are added together to obtain the second voltage target signal; The second voltage target signal is input into the PWM modulation module to generate and output a third PWM signal, wherein the third PWM signal is used to drive the L2 line inverter circuit.

2. The system according to claim 1, characterized in that, The L1 line inverter circuit includes a first input filter unit and a first power conversion unit; The first input filtering unit is connected to the input terminals of the battery and the first power conversion unit, respectively. The first input filtering unit is configured to filter the current output by the battery and output a first current. The output terminal of the first power conversion unit is connected to the input terminal of the first output filter circuit, and the control terminal of the first power conversion unit is connected to the controller. The controller is configured to control the first power conversion unit to operate in a current source state when the power grid is connected, so as to output the first voltage to the first load based on the power grid voltage and the first current. It is also configured to control the first power conversion unit to operate in a voltage source state when the power grid is de-energized, so as to output the third voltage to the first load based on the first current.

3. The system according to claim 2, characterized in that, The L2 line inverter circuit includes a second input filter unit and a second power conversion unit; The second input filtering unit is connected to the input terminals of the battery and the second power conversion unit, respectively. The second input filtering unit is configured to filter the current output by the battery and output a second current. The output terminal of the second power conversion unit is connected to the input terminal of the second output filter circuit, and the control terminal of the second power conversion unit is connected to the controller. The controller is configured to control the second power conversion unit to operate in voltage source state when the power grid is connected or when the power grid is de-energized, so as to output the second voltage to the second load based on the second current.

4. The system according to claim 3, characterized in that, Both the first power conversion unit and the second power conversion unit are T-type inverter bridges.

5. The system according to claim 1, characterized in that, The first output filter circuit includes a first inductor and a first capacitor, and the second output filter circuit includes a second inductor and a second capacitor; One end of the first inductor is connected to the L1 line inverter circuit, and the other end of the first inductor is connected to one end of the first capacitor, the power grid and the first load, respectively. One end of the second inductor is connected to the L2 line inverter circuit, and the other end of the second inductor is connected to one end of the second capacitor and the second load, respectively.

6. The system according to any one of claims 1-5, characterized in that, Also includes: Grid-connected switching circuit; One end of the grid-connected switch circuit is connected to the output terminal of the first output filter circuit and the first load, respectively, and the other end of the grid-connected switch circuit is connected to the power grid. The grid-connected switch circuit is configured to control the connection state between the power grid and the first load.

7. A control method, characterized in that, Applied to the controller as described in any one of claims 1-6, the method comprises: When the grid is connected, the L1 line inverter circuit is controlled to operate in the current source state to output a first voltage to the first load, and the L2 line inverter circuit is controlled to operate in the voltage source state to output a second voltage to the second load. The first voltage is determined by the grid voltage of the grid, and the second voltage is determined by the output voltage of the L2 line inverter circuit. When the power grid fails, the L1 line inverter circuit is controlled to operate in voltage source mode to output a third voltage to the first load, and the L2 line inverter circuit is controlled to operate in voltage source mode to output a second voltage to the second load. The third voltage is determined by the output voltage of the L1 line inverter circuit. The control of the L2 line inverter circuit to operate in voltage source mode includes: The output voltage of the L2 line inverter circuit is sampled to obtain the second voltage feedback signal; The second voltage deviation signal is obtained by subtracting the second voltage feedback signal from the second voltage reference signal, and then the second current reference signal is obtained by passing it through the voltage loop regulator; The inductor current flowing through the second output filter circuit is sampled to obtain the second sampled current; The second current deviation signal is obtained by subtracting the second sampling current from the second current reference signal, and then the second voltage compensation signal is obtained by passing it through the current loop regulator. The second voltage compensation signal, the second voltage reference signal, and the load current feedforward of the second load are added together to obtain the second voltage target signal; The second voltage target signal is input into the PWM modulation module to generate and output a third PWM signal, wherein the third PWM signal is used to drive the L2 line inverter circuit.

8. The method according to claim 7, characterized in that, The control of the L1 line inverter circuit to operate in current source mode includes: The dq-axis reference current is obtained by performing a DQ transformation on the reference current; The inductor current flowing through the first output filter circuit is sampled to obtain the first sampled current; The first sampled current is subjected to DQ transformation to obtain the dq-axis sampled current; The dq-axis current deviation is obtained by subtracting the dq-axis sampling current from the dq-axis reference current. The voltage signal compensation amount is obtained by passing the dq axis current deviation through the current loop regulator, wherein the voltage signal compensation amount is the voltage signal in the dq axis coordinate system; The voltage signal compensation amount is added to the dq-axis component of the grid voltage to obtain the corrected voltage reference signal; The corrected voltage reference signal is subjected to DQ inverse transform to obtain the L1 line voltage reference signal; The L1 line voltage reference signal is input to the PWM modulation module to generate and output a first PWM signal, wherein the first PWM signal is used to drive the L1 line inverter circuit.

9. The method according to claim 7, characterized in that, The control of the L1 line inverter circuit to operate in voltage source mode includes: The output voltage of the L1 line inverter circuit is sampled to obtain the first voltage feedback signal; The first voltage deviation signal is obtained by subtracting the first voltage feedback signal from the first voltage reference signal, and then the first current reference signal is obtained by passing it through the voltage loop regulator; The inductor current flowing through the first output filter circuit is sampled to obtain the first sampled current; The first current deviation signal is obtained by subtracting the first sampling current from the first current reference signal, and then the first voltage compensation signal is obtained by passing it through the current loop regulator. The first voltage compensation signal, the first voltage reference signal, and the load current feedforward of the first load are added together to obtain the first voltage target signal; The first voltage target signal is input into the PWM modulation module to generate and output a second PWM signal, wherein the second PWM signal is used to drive the L1 line inverter circuit.

10. A controller, characterized in that, The controller includes: At least one processor; and, A non-volatile memory communicatively connected to the at least one processor, the non-volatile memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the control method as described in any one of claims 7-9.

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