Split-phase inverter circuit control method, device, storage medium and split-phase inverter circuit

Abstract

The present application relates to a split-phase inverter circuit control method, device, storage medium and split-phase inverter circuit, the method comprising: obtaining the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit; determining the AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient, and determining the AC side current difference according to the AC side current and the AC side target active current; converting the AC side current difference into a gain value through a quasi-proportional resonant controller, and determining a modulation signal according to the DC side voltage, the AC side voltage and the gain value; controlling the on and off of a switch device in the split-phase inverter circuit according to the modulation signal. By determining the AC side current difference and converting the AC side current difference into a gain value through a quasi-proportional resonant controller, the harmonics existing in the circuit can be accurately suppressed, the output harmonics in the circuit can be effectively reduced, and the loss in the power system can be reduced, and the power quality can be improved.

Description

Technical Field

[0001] The present application relates to the field of inverter control technology, and in particular to a split-phase inverter circuit control method, device, storage medium and split-phase inverter circuit. Background Art

[0002] The split-phase inverter circuit is a power electronic circuit used to convert DC power into AC power. It can be used in application scenarios that require a split-phase grid (usually 120V phase voltage and 240V line voltage). Specifically, the split-phase inverter circuit can be used in home backup power systems to provide power when the city power is interrupted to ensure the normal operation of home appliances; it can also be used in hybrid and electric vehicles to convert the DC power of the battery into AC power suitable for the motor, etc.

[0003] However, in the process of converting DC to AC by the split-phase inverter circuit, harmonics may be generated due to the inverter method or load characteristics. For example, the high-frequency switching operation of the switching devices in the split-phase inverter circuit may introduce high-frequency components and harmonics, and the motor may also introduce nonlinear load characteristics during startup and operation, increasing the harmonic content. Harmonic components will lead to increased losses in the power system, including transmission line losses and internal equipment losses. In addition, harmonic components will cause distortion of the voltage waveform, resulting in a decrease in power quality.

[0004] Based on this, a split-phase inverter circuit control method that can reduce output harmonics is urgently needed in traditional technology. Summary of the invention

[0005] Based on this, it is necessary to provide a split-phase inverter circuit control method, device, storage medium and split-phase inverter circuit that can reduce output harmonics in response to the above-mentioned technical problems.

[0006] In a first aspect, the present application provides a split-phase inverter circuit control method. The method comprises:

[0007] Obtaining a DC side voltage, an AC side voltage, and an AC side current of a split-phase inverter circuit;

[0008] Determine an AC side target active current according to the AC side voltage, the DC side voltage and a first coefficient, and determine an AC side current difference according to the AC side current and the AC side target active current;

[0009] The AC side current difference is converted into a gain value by a quasi-proportional resonant controller, and a modulation signal is determined according to the DC side voltage, the AC side voltage and the gain value;

[0010] The on and off of the switching device in the split-phase inverter circuit is controlled according to the modulation signal.

[0011] In one embodiment, determining the AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient includes:

[0012] Determining the phase angle of each phase on the AC side according to the AC side voltage;

[0013] Determining a DC side target active current according to the DC side voltage and the first coefficient;

[0014] The target active current on the AC side is determined according to the phase angle and the target active current on the DC side.

[0015] In one embodiment, the AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and determining the phase angle of each phase of the AC side according to the AC side voltage includes:

[0016] Phase-locking the first split-phase AC voltage by a phase-locked loop to obtain a first phase-locked angle;

[0017] The second split-phase AC voltage is phase-locked by the phase-locked loop to obtain a second phase-locked angle.

[0018] In one of the embodiments, before determining the DC side target active current according to the DC side voltage and the first coefficient, the method further includes:

[0019] Dividing the DC side voltage to obtain a first DC voltage and a second DC voltage;

[0020] Performing software filtering on the first DC voltage to obtain a first filtered DC voltage;

[0021] The second DC voltage is software filtered to obtain a second filtered DC voltage.

[0022] In one embodiment, determining the DC side target active current according to the DC side voltage and the first coefficient includes:

[0023] Determine a target DC voltage according to the DC side voltage and a second coefficient;

[0024] A filtered voltage sum of the first filtered DC voltage and the second filtered DC voltage is determined, and the DC side target active current is determined according to a difference between the target DC voltage and the filtered voltage sum and the first coefficient.

[0025] In one embodiment, determining the AC side current difference according to the AC side current and the AC side target active current comprises:

[0026] Determining a voltage-sharing current according to a voltage-sharing voltage and a third coefficient, wherein the voltage-sharing voltage includes a difference between the first filtered DC voltage and the second filtered DC voltage;

[0027] Determine the target current on the AC side according to the sum of the target active current on the AC side and the voltage-sharing current;

[0028] The AC side current difference is determined according to the AC side target current and the difference between the AC side current.

[0029] In one embodiment, converting the AC side current difference into a gain value by using a quasi-proportional resonant controller comprises:

[0030] Inputting the AC side current difference into the quasi-proportional resonant controller, and outputting a basic gain after calculation according to a bilinear variation transfer function in the quasi-proportional resonant controller;

[0031] Determine an additional gain according to the AC side voltage difference and a fourth coefficient;

[0032] The gain value is determined according to the basic gain and the additional gain.

[0033] In one embodiment, determining the modulation signal according to the DC side voltage, the AC side voltage and the gain value comprises:

[0034] Determine that the sum of the AC side voltage and the gain value is the AC transient voltage;

[0035] Determining a duty cycle of each phase on the AC side according to the AC transient voltage and the DC side voltage;

[0036] According to the duty cycle of each phase of the AC side and a preset modulation period, the on-time of each level voltage is determined as the modulation signal.

[0037] In one of the embodiments, after controlling the on and off of the switch device in the split-phase inverter circuit according to the modulation signal, the method further includes:

[0038] Determine an average DC voltage of a plurality of the DC link voltages within a target period according to a sampling quantity, wherein the sampling quantity includes the number of times the DC link voltage is collected within a sampling period;

[0039] determining a difference between the average DC voltage and the target DC voltage;

[0040] If the difference is less than a preset threshold, reducing the target DC voltage by a first threshold;

[0041] If the difference is greater than or equal to the preset threshold, the target DC voltage is increased by a second threshold.

[0042] In one embodiment, the method further comprises:

[0043] determining the circuit output power before and after the change when the target DC voltage changes, wherein the target DC voltage change includes reducing or increasing the target DC voltage;

[0044] If the circuit output power before the change is greater than the circuit output power after the change, reducing the target DC voltage by a third threshold;

[0045] If the circuit output power before the change is less than the circuit output power after the change, the target DC voltage is increased by a fourth threshold.

[0046] In a second aspect, the present application further provides a split-phase inverter circuit control device, the device comprising:

[0047] A data acquisition module, used to acquire the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit;

[0048] an AC side current difference determination module, configured to determine an AC side target active current according to the AC side voltage, the DC side voltage and a first coefficient, and to determine an AC side current difference according to the AC side current and the AC side target active current;

[0049] A signal modulation module, used for converting the AC side current difference into a gain value through a quasi-proportional resonant controller, and determining a modulation signal according to the DC side voltage, the AC side voltage and the gain value;

[0050] A control module is used to control the on and off of the switch device in the split-phase inverter circuit according to the modulation signal.

[0051] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the split-phase inverter circuit control method described in any one of the first aspects are implemented.

[0052] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the split-phase inverter circuit control method described in any one of the first aspects are implemented.

[0053] In a fifth aspect, the present application further provides a split-phase inverter circuit, the split-phase inverter circuit comprising a DC power supply, a voltage divider module, a first inverter module, a second inverter module, a first AC bus and a second AC bus, the voltage divider module is connected in parallel with the DC power supply, the voltage divider module is also connected to the first inverter module and the second inverter module respectively, the first inverter module is also connected to the first AC bus, the second inverter module is also connected to the second AC bus, wherein,

[0054] The voltage dividing module comprises a first voltage dividing unit and a second voltage dividing unit connected in series;

[0055] The first inverter module includes a first transistor, a second transistor, a third transistor and a fourth transistor, the emitter of the first transistor is connected to the first end of the first voltage divider unit, the collector of the first transistor is connected to the first AC bus, the emitter of the second transistor, and the collector of the fourth transistor respectively, the collector of the second transistor is connected to the first end of the second voltage divider unit, the emitter of the fourth transistor is connected to the emitter of the third transistor, and the collector of the third transistor is connected to the second end of the first voltage divider unit and the second end of the second voltage divider unit respectively;

[0056] The second inverter module includes a fifth transistor, a sixth transistor, a seventh transistor and an eighth transistor, the emitter of the fifth transistor is connected to the first end of the first voltage divider unit, the collector of the fifth transistor is respectively connected to the emitter of the sixth transistor, the collector of the eighth transistor and the second AC bus, the collector of the sixth transistor is connected to the first end of the second voltage divider unit, the emitter of the eighth transistor is connected to the emitter of the seventh transistor, and the collector of the seventh transistor is respectively connected to the second end of the first voltage divider unit and the second end of the second voltage divider unit.

[0057] In one embodiment, the split-phase inverter circuit further includes a first filter module, a second filter module and a neutral line, and the neutral line is connected to the second end of the first voltage divider unit and the second end of the second voltage divider unit respectively, wherein:

[0058] The first filtering module includes a first inductor, a second inductor and a third capacitor, the first end of the first inductor is respectively connected to the collector of the first transistor, the emitter of the second transistor and the collector of the fourth transistor, the second end of the first inductor is respectively connected to the first end of the second inductor and the first end of the third capacitor, the second end of the second inductor is connected to the first AC bus, and the second end of the third capacitor is connected to the neutral line;

[0059] The first filtering module includes a third inductor, a fourth inductor and a fourth capacitor, the first end of the third inductor is respectively connected to the collector of the fifth transistor, the emitter of the sixth transistor and the collector of the eighth transistor, the second end of the third inductor is respectively connected to the first end of the fourth inductor and the first end of the fourth capacitor, the second end of the fourth inductor is connected to the second AC bus, and the second end of the fourth capacitor is respectively connected to the neutral line and the second end of the third capacitor.

[0060] The above-mentioned split-phase inverter circuit control method, device, storage medium and split-phase inverter circuit determine the target active current on the AC side by obtaining the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit, and then determine the AC side current difference, and then convert the AC side current difference into a gain value through a quasi-proportional resonant controller, and determine the modulation signal according to the DC side voltage, the AC side voltage and the gain value, and control the on and off of the switching device in the split-phase inverter circuit according to the modulation signal. By determining the AC side current difference and converting the AC side current difference into a gain value through a quasi-proportional resonant controller, the harmonics existing in the circuit can be accurately suppressed, and the output harmonics in the circuit can be effectively reduced, thereby reducing the loss in the power system and improving the power quality.

[0061] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0063] Figure 1 It is a structural diagram of an application circuit of a split-phase inverter circuit control method in one embodiment;

[0064] Figure 2 1 is a flow chart of a method for controlling a split-phase inverter circuit in one embodiment;

[0065] Figure 3 A schematic diagram of a process of determining a phase-locked angle through a phase-locked loop in one embodiment;

[0066] Figure 4 A schematic diagram of a process for determining a gain value by a quasi-proportional resonant controller in one embodiment;

[0067] Figure 5 It is a flowchart of a method for controlling a split-phase inverter circuit in a specific embodiment;

[0068] Figure 6is a structural block diagram of a split-phase inverter circuit control device in one embodiment;

[0069] Figure 7 is an internal structure diagram of a computer device in one embodiment;

[0070] Figure 8 Schematic diagram of a split-phase inverter circuit in one embodiment. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0072] The terms "module", "unit", etc. used below are a combination of software and / or hardware that can implement a predetermined function. Although the devices described in the following embodiments are preferably implemented in hardware, the implementation of software, or a combination of software and hardware is also possible and conceivable.

[0073] The split-phase inverter circuit control method provided in the embodiment of the present application can be applied to Figure 1 In the split-phase inverter circuit shown in the figure, the DC side voltage provided by the DC power supply is divided by the first voltage divider unit and the second voltage divider unit to obtain the first DC voltage and the second DC voltage on the DC side after the voltage division. After the DC side voltage is inverted by the first inverter module, the first split-phase AC voltage is output by the first AC bus; after the DC side voltage is inverted by the second inverter module, the second split-phase AC voltage is output by the second AC bus. A neutral line is drawn out at the midpoint of the first voltage divider unit and the second voltage divider unit.

[0074] In the present application embodiment, Figure 2 As shown, a split-phase inverter circuit control method is provided, the method comprising:

[0075] S201: Obtaining a DC side voltage, an AC side voltage, and an AC side current of a split-phase inverter circuit.

[0076] In an embodiment of the present application, the DC side voltage may include the voltages on both sides of the DC power supply in the split-phase inverter circuit, and may also include the voltage after the DC side voltage is divided. Among them, the DC power supply may include an energy storage battery, and may also include a photovoltaic panel. Specifically, after the two voltage-dividing units divide the DC power supply, the DC side voltage may include the voltages on both sides of each voltage-dividing unit. The AC side voltage may include the zero-line voltage of each phase AC bus after the phase split. The AC side current may include the current on each phase AC bus after the phase split.

[0077] In the embodiment of the present application, the analog quantity can be sampled through the AD (Analogue-to-Digital conversion) interface of the DSP (digital signal processing) chip, and then the sampled data is converted into actual values ​​to obtain the DC side voltage, AC side voltage and AC side current.

[0078] In some specific embodiments, the DC side voltage value obtained may include the power supply voltage Udc, the first DC voltage UbusP obtained by dividing the power supply voltage, and the second DC voltage UbusN. The AC side voltage obtained may include the first split-phase AC voltage Uac_a on the first AC bus a, and the second split-phase AC voltage Uac_c on the second AC bus c. The AC side current obtained may include the first split-phase AC current Iac_a on the first AC bus a, and the second split-phase AC current Iac_c on the second AC bus c.

[0079] S203: Determine an AC side target active current according to the AC side voltage, the DC side voltage, and a first coefficient, and determine an AC side current difference according to the AC side current and the AC side target active current.

[0080] In the embodiment of the present application, the AC side target active current can be determined according to the AC side voltage, the DC side voltage and the first coefficient. In some embodiments, determining the AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient includes:

[0081] S301: Determine the phase angle of each phase on the AC side according to the AC side voltage.

[0082] S303: Determine a DC side target active current according to the DC side voltage and the first coefficient.

[0083] S305: Determine an AC side target active current according to the phase angle and the DC side target active current.

[0084] In an embodiment of the present application, if the target active current on the AC side is to be determined, the phase angle of each phase on the AC side needs to be determined. The phase angle of each phase on the AC side includes the transient phase of each phase. The split-phase inverter circuit is different from the more common three-phase inverter circuit, and it is difficult to determine the phase angle of each phase through the conversion method in traditional technology. That is, it is difficult to directly convert from the A, B, and C axes to the α, β, and γ axes, and then convert from the α, β, and γ axes to the d, q, and 0 axes, and then use the q value of 0 for angle tracking to determine the phase angle of each phase.

[0085] Based on this, an embodiment of the present application provides a method for determining the phase angle of each phase on the AC side. In some embodiments, the AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and determining the phase angle of each phase on the AC side according to the AC side voltage includes:

[0086] S3011: Phase-lock the first split-phase AC voltage through a phase-locked loop to obtain a first phase-locked angle.

[0087] S3013: Phase-locking the second split-phase AC voltage through the phase-locked loop to obtain a second phase-locked angle.

[0088] In the embodiment of the present application, the first split-phase AC voltage Uac_a and the second split-phase AC voltage Uac_c can be phase-locked respectively by a phase-locked loop (PLL) to obtain a first phase-locked angle θa and a second phase-locked angle θc as the phase angle of each phase on the AC side.

[0089] The main method of determining the phase-locked angle through phase-locked loop can be referred to Figure 3 As shown, the AC side voltage and angular frequency are input into a second-order generalized integrator (SOGI), and then the voltage reactive axis component Uq is determined through conversion of the α, β and dq axes, and the phase-locked angle of each phase is obtained by inputting the proportional integrator (PI). Among them, the second-order generalized integrator is an artificially constructed single-phase system phase-locking strategy with the same amplitude as the input signal and a phase difference of 90 degrees, which is similar to the scheme of converting the A, B, and C phase voltages into α and β axis voltages in three-phase AC. After converting to the α and β axes, they are converted to the dq axis for angle tracking. If there is no error in the angle tracking, the value of the active axis d should be the peak value or effective value of the input voltage effective value, and the value of the reactive axis q should be close to 0. The specific phase-locking method can refer to the implementation method in the prior art, and this application will not go into details.

[0090] Since the acquired DC side voltage may fluctuate, the present application may also implement filtering of the DC side voltage through software. In some embodiments, before determining the DC side target active current according to the DC side voltage and the first coefficient, it also includes:

[0091] S401: Dividing the DC side voltage to obtain a first DC voltage and a second DC voltage;

[0092] S403: Perform software filtering on the first DC voltage to obtain a first filtered DC voltage.

[0093] S405: Perform software filtering on the second DC voltage to obtain a second filtered DC voltage.

[0094] In an embodiment of the present application, the DC side voltage may be a DC power supply voltage. The first DC voltage UbusP and the second DC voltage UbusN are obtained by dividing the DC power supply voltage. After inverting the first DC voltage UbusP and the second DC voltage UbusN, the first split-phase AC voltage Uac_a on the first AC bus a and the second split-phase AC voltage Uac_c on the second AC bus c are obtained. The first DC voltage UbusP is software filtered to obtain the first filtered DC voltage UbusP_IIR, and the second DC voltage UbusN is software filtered to obtain the second filtered DC voltage UbusN_IIR. The DC voltage control part of the present application adopts a software filter control strategy, which can reduce the impact of DC fluctuations on the output current, reduce the current fluctuations caused by the double frequency fluctuations of the DC bus voltage, and improve the quality of electric energy.

[0095] After determining the phase angle of each phase on the AC side, the DC side target active current can be determined according to the DC side voltage and the first coefficient. In some embodiments, determining the DC side target active current according to the DC side voltage and the first coefficient includes:

[0096] S3031: Determine a target DC voltage according to the DC side voltage and a second coefficient.

[0097] S3033: Determine a filtered voltage sum of the first filtered DC voltage and the second filtered DC voltage, and determine the DC side target active current according to a difference between the target DC voltage and the filtered voltage sum and the first coefficient.

[0098] In an embodiment of the present application, determining the target DC voltage according to the DC side voltage and the second coefficient may include determining the initial voltage according to the DC side voltage, and then taking the difference between the initial voltage and the second coefficient as the target DC voltage. Specifically, the maximum DC side voltage is usually a preset multiple of the open circuit voltage, such as 0.8 times. Let the DC side power supply voltage Udc in the case of no output power be the starting voltage UdcStart, that is, the starting voltage UdcStart is set according to the preset multiple as the voltage after the DC side power supply voltage Udc is reduced, and the preset multiple is less than 1. Then the target DC voltage Udcflag=starting voltage UdcStart-second coefficient. In some specific embodiments, the second coefficient may be 3V.

[0099] Furthermore, according to the difference between the target DC voltage and the filtered voltage sum and the first coefficient, the DC side target active current Idflag can be determined by formula (1).

[0100] Idflag= K1×(Udcflag-(UbusP_IIR+UbusN_IIR) ) (1)

[0101] In formula (1), Idflag is the target active current on the DC side, K1 is the first coefficient, Udcflag is the target DC voltage, (UbusP_IIR+UbusN_IIR) is the filtered voltage sum of the first filtered DC voltage UbusP_IIR and the second filtered DC voltage UbusN_IIR. K1 is the proportional parameter obtained by debugging.

[0102] Further, after determining the phase angle and the target active current on the DC side, the target active current on the AC side may be determined, wherein the target active current on the AC side may include a first target active current on the first AC bus and a second target active current on the second AC bus.

[0103] In some embodiments, the DC side target active current Idflag and the sine value sin(θa) of the first phase lock angle θa are multiplied as the first target active current Iaca_YouGon, and the DC side target active current Idflag and the sine value sin(θc) of the second phase lock angle θc are multiplied as the second target active current Iacc_YouGon.

[0104] Furthermore, after determining the target active current on the AC side, the first DC voltage UbusP and the second DC power supply UbusN after voltage division on the DC side may not be equal when outputting active power, and voltage balancing is required to make them equal. In traditional technology, hardware is usually used for voltage balancing, which increases the cost of circuit design and the difficulty of installation.

[0105] Based on this, an embodiment of the present application provides a method for software voltage balancing and determining the AC side current difference. In some embodiments, determining the AC side current difference according to the AC side current and the AC side target active current includes:

[0106] S501: Determine a voltage-sharing current according to a voltage-sharing voltage and a third coefficient, wherein the voltage-sharing voltage includes a difference between the first filtered DC voltage and the second filtered DC voltage.

[0107] S503: Determine an AC side target current according to the sum of the AC side target active current and the voltage-sharing current.

[0108] S505: Determine the AC side current difference according to the AC side target current and the difference between the AC side current.

[0109] In the embodiment of the present application, the difference between the first filtered DC voltage UbusP_IIR and the second filtered DC voltage UbusN_IIR is used as the voltage sharing voltage Ubus_Jun, and the voltage sharing current Iacajun_Flag is determined according to the product of the voltage sharing voltage Ubus_Jun and the third coefficient K2, wherein the third coefficient K2 is a proportional parameter obtained by actual debugging.

[0110] Further, the AC side target current is determined according to the sum of the AC side target active current and the voltage-sharing current. The AC side target current includes a target value of the actual output current required. The AC side target current may include a first target current on the first AC bus and a second target current on the second AC bus.

[0111] In some specific embodiments, the first target current Iacaflag may be determined according to the sum of the first target active current Iaca_YouGon and the voltage-sharing current Iacajun_Flag, and the second target current Iaccflag may be determined according to the sum of the second target active current Iacc_YouGon and the voltage-sharing current Iacajun_Flag.

[0112] Further, the AC side current difference can be determined according to the difference between the AC side target current and the AC side current. The AC side current difference can include a first AC difference on the first AC bus and a second AC difference on the second AC bus. The AC side current can include a first split-phase AC current on the first AC bus and a second split-phase AC current on the second AC bus.

[0113] In some specific embodiments, the first AC error Iaca_Error is determined according to the difference between the first target current Iacaflag and the first split-phase AC current Iac_a, and the second AC error Iacc_Error is determined according to the difference between the second target current Iaccflag and the second split-phase AC current Iac_c.

[0114] S205: Convert the AC side current difference into a gain value through a quasi-proportional resonant controller, and determine a modulation signal according to the DC side voltage, the AC side voltage and the gain value.

[0115] In traditional technology, the current loop is usually tracked using a PI (proportional integral) controller. However, PI tracking has a better control effect on DC quantities, but a poor control effect on AC quantities. Based on this, the present application uses a quasi-proportional resonant controller (QPR) to track the current.

[0116] In some embodiments, converting the AC side current difference into a gain value by using a quasi-proportional resonant controller comprises:

[0117] S601: Input the AC side current difference into the quasi-proportional resonant controller, and output a basic gain after calculation according to a bilinear variation transfer function in the quasi-proportional resonant controller.

[0118] S603: Determine an additional gain according to the AC side voltage difference and a fourth coefficient.

[0119] S605: Determine the gain value according to the basic gain and the additional gain.

[0120] In the embodiment of the present application, the AC side current difference is input into the quasi-proportional resonant controller, wherein the transfer function of the quasi-proportional resonant controller is shown in formula (2).

[0121] (2)

[0122] The transfer function G(s) shown in equation (2) aims to control the gain amplification at the frequency ωo rather than the gain at ωo close to 0. ωc is the added margin so that the gain can be amplified at the frequency of the gain amplification point around ωo. Kp is the proportional gain coefficient, Kr is the integral gain coefficient, and s is the complex frequency variable in the analog domain.

[0123] The transfer function G(s) is discretized using the bilinear transformation method Tustin to obtain equation (3).

[0124] (3)

[0125] Bilinear Transform is a method for converting an analog filter into a digital filter. It achieves this conversion by mapping the transfer function on the s plane in the analog domain to the transfer function on the z plane in the digital domain. Formula (3) is the result obtained after mapping the analog domain transfer function (2) to the digital domain. The meanings of the parameters ωo, ωc, and Kr in formula (3) are consistent with those in formula (2). k is 2 / T, where T is the sampling period for obtaining the DC side voltage, AC side voltage, and AC side current, and z is the complex frequency variable in the digital domain. In some specific embodiments, the sampling period can be 65us.

[0126] The first AC difference Iaca_Error is input into the quasi-proportional resonant controller, and the basic gain is calculated as Iqpra_out according to the bilinear change transfer function in the quasi-proportional resonant controller. The additional gain is determined according to the product of the first AC difference Iaca_Error and the fourth coefficient Kp. The first AC gain value Iacaout is then determined based on the sum of the basic gain Iqpra_out and the additional gain (Iaca_Error×Kp). Similar to the first AC gain value, the second AC difference Iacc_Error is input into the quasi-proportional resonant controller, and the second AC gain value Iaccout can be determined after the above calculation. The specific method of calculating the AC side current difference by the quasi-proportional resonant controller to obtain the basic gain can refer to the prior art, and this application will not repeat it.

[0127] In the embodiment of the present application, the schematic diagram for determining the gain value is as follows: Figure 4As shown in the figure, after the AC side current difference is input into the quasi-proportional resonant controller, the final output gain value can be determined by calculation based on the first harmonic of ωo, the third harmonic of (ωo×3), the fifth harmonic of (ωo×5) and the fourth coefficient Kp. It should be noted that more harmonic gains can be added according to the actual current output. The purpose is to extract the low-order harmonics of the AC output current and output the fundamental current after control. ωo is the fundamental frequency.

[0128] Further, after determining the gain value, a modulation signal may be determined according to the DC side voltage, the AC side voltage and the gain value. In some embodiments, determining the modulation signal according to the DC side voltage, the AC side voltage and the gain value includes:

[0129] S701: Determine that the sum of the AC side voltage and the gain value is an AC transient voltage.

[0130] S703: Determine a duty cycle of each phase on the AC side according to the AC transient voltage and the DC side voltage.

[0131] S705: Determine the on-time of each level voltage as the modulation signal according to the duty cycle of each phase of the AC side and a preset modulation period.

[0132] In an embodiment of the present application, the AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and the AC transient voltage may include a first AC transient voltage on the first AC bus and a second AC transient voltage on the second AC bus.

[0133] In some specific embodiments, the first AC transient voltage Uouta is determined according to the sum of the first split-phase AC voltage Uac_a and the first AC gain value Iacaout for feedforward control. It should be noted that the gain value is a voltage signal. The first duty cycle Da on the first AC bus is then determined according to the first AC transient voltage Uouta and the DC side power supply voltage Udc. Specifically, the first duty cycle Da= first AC transient voltage Uouta / (0.5×DC side power supply voltage Udc). Then, the on-time of each level voltage is determined as a modulation signal according to the product of the first duty cycle Da and the preset modulation period T. Among them, the preset modulation period includes the period of the PWM (pulse width modulation) wave. On the other hand, the determination method of the second duty cycle Dc on the second AC bus is similar to the first duty cycle Da, which will not be repeated here. It should be noted that each phase of the AC side of the split-phase inverter circuit can output three-level voltages, namely, positive level voltage Up, negative level voltage Un, and 0 voltage, and the modulation signal includes the on-time of each level voltage.

[0134] S207: Controlling the on and off of the switching devices in the split-phase inverter circuit according to the modulation signal.

[0135] In the embodiment of the present application, the on and off of the switch device in the split-phase inverter circuit can be controlled according to the modulation signal, and then the modulated AC voltage is output through the AC side. The switch device may include a diode, an insulated gate field effect transistor (MOS), an insulated gate bipolar transistor (IGBT), etc.

[0136] In an embodiment of the present application, the target active current on the AC side is determined by acquiring the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit, and then the AC side current difference is determined, and then the AC side current difference is converted into a gain value through a quasi-proportional resonant controller, and a modulation signal is determined according to the DC side voltage, the AC side voltage and the gain value, and the on and off of the switching device in the split-phase inverter circuit is controlled according to the modulation signal. By determining the AC side current difference and converting the AC side current difference into a gain value through a quasi-proportional resonant controller, it is possible to accurately suppress the harmonics present in the circuit, effectively reduce the output harmonics in the circuit, and then reduce the loss in the power system and improve the power quality. On the other hand, the present application converts the AC side current difference into a gain value through a quasi-proportional resonant controller, which can perform zero-static error regulation and also makes the modulated voltage have good dynamic stability.

[0137] In order to make the DC voltage more stable, the embodiment of the present application can also track the voltage. In some embodiments, after controlling the on and off of the switch device in the split-phase inverter circuit according to the modulation signal, it also includes:

[0138] S801: Determine an average DC voltage of a plurality of DC link voltages within a target period according to a sampling quantity, where the sampling quantity includes the number of times the DC link voltage is collected within a sampling period.

[0139] S803: Determine a difference between the average DC voltage and the target DC voltage.

[0140] S805: If the difference is less than a preset threshold, reducing the target DC voltage by a first threshold.

[0141] S807: If the difference is greater than or equal to the preset threshold, increase the target DC voltage by a second threshold.

[0142] In the embodiment of the present application, the DC side power supply voltage changes frequently, and it is necessary to improve the stability of the DC side voltage. The average DC voltage of multiple DC side voltages Udc in the target period is determined according to the number of samples, and the number of samples includes the number of times the DC side voltage is collected in the sampling period. For example, if the number of times the DC side power supply voltage Udc is collected in the sampling period is 250 times, the average value of the 250 sampled voltages is calculated as the average DC voltage.

[0143] Further, the difference between the average DC voltage and the target DC voltage Udcflag is determined. If the difference is less than the preset threshold, it means that the DC side voltage is relatively stable, and the target DC voltage Udcflag is reduced by the first threshold so that the AC voltage is close to the voltage corresponding to the maximum output power point. If the difference is greater than or equal to the preset threshold, the target DC voltage Udcflag is increased by the second threshold, which means that the DC side voltage is unstable, and the target DC voltage Udcflag is increased by the second threshold. Among them, the preset threshold can be 1V. The first threshold and the second threshold can be the same as 3V, or they can be different. The preset threshold, the first threshold and the second threshold can be set according to the actual application scenario.

[0144] It should be noted that on the right side of the voltage value corresponding to the maximum power point, the split-phase inverter circuit operates in a stable state, so reducing the target DC voltage can make the operating voltage close; and on the left side of the voltage value corresponding to the maximum power point, the split-phase inverter circuit operates in an unstable state, so it is necessary to increase the target DC voltage to make the circuit work stably.

[0145] The present application also provides a method for making the split-phase inverter circuit operate at a maximum power point. In some embodiments, the split-phase inverter circuit control method further includes:

[0146] S901: Determine the circuit output power before and after the change when the target DC voltage changes, wherein the target DC voltage change includes decreasing or increasing the target DC voltage.

[0147] S903: If the circuit output power before the change is greater than the circuit output power after the change, reducing the target DC voltage by a third threshold.

[0148] S905: If the circuit output power before the change is less than the circuit output power after the change, increasing the target DC voltage by a fourth threshold.

[0149] In the embodiment of the present application, the change of the target DC voltage Udcflag includes a decrease or increase in the target DC voltage. When the target DC voltage Udcflag changes, the circuit output power before the change and the circuit output power after the change are determined. If the circuit output power before the change is greater than the circuit output power after the change, the target DC voltage is reduced by a third threshold; if the circuit output power before the change is less than the circuit output power after the change, the target DC voltage is increased by a fourth threshold, thereby tracking the maximum output power point of the split-phase inverter circuit. The third threshold and the fourth threshold may be the same or different, and may be set according to the actual application scenario.

[0150] The control method of the split-phase inverter circuit of the present application is described below through specific embodiments. Figure 5As shown, by sampling at a sampling period of 65us and converting the analog quantity into an actual value, the AC side voltage, the DC side voltage after voltage division UbusP, UbusN and the AC side current are obtained. The AC side voltage is phase-locked by a phase-locked loop to obtain a phase-locked angle. After software filtering of the DC side voltages UbusP and UbusN, the target active current on the DC side is determined according to the target DC voltage, the difference between the filtered voltage and the first coefficient K1. The target active current on the AC side is determined according to the phase-locked angle and the target active current on the DC side. The equalizing voltage is determined according to the difference in the filtered voltages, and the equalizing current is determined according to the equalizing voltage and the third coefficient K2. The target current on the AC side is determined according to the sum of the target active current on the AC side and the equalizing current. The current difference on the AC side is determined according to the difference between the target current on the AC side and the current on the AC side. The current difference on the AC side is input into the quasi-proportional resonant controller to determine the gain value. The sum of the AC side voltage and the gain value is determined as the AC transient voltage. The duty cycle of each phase on the AC side is determined according to the AC transient voltage and the DC side voltage. According to the duty cycle of each phase on the AC side and the preset modulation period, the on-time of each level voltage is determined as the modulation signal. The on-off of the switching device in the split-phase inverter circuit is controlled according to the modulation signal to generate the target voltage waveform.

[0151] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0152] Based on the same inventive concept, the embodiment of the present application also provides a split-phase inverter circuit control device 1100 for implementing the split-phase inverter circuit control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the split-phase inverter circuit control device 1100 provided below can refer to the limitations of the split-phase inverter circuit control method above, and will not be repeated here.

[0153] In one embodiment, Figure 6 As shown, a split-phase inverter circuit control device 1100 is provided, comprising:

[0154] The data acquisition module 1101 is used to acquire the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit;

[0155] an AC side current difference determination module 1102, configured to determine an AC side target active current according to the AC side voltage, the DC side voltage and a first coefficient, and to determine an AC side current difference according to the AC side current and the AC side target active current;

[0156] A signal modulation module 1103, configured to convert the AC side current difference into a gain value through a quasi-proportional resonant controller, and determine a modulation signal according to the DC side voltage, the AC side voltage and the gain value;

[0157] The control module 1104 is used to control the on and off of the switch device in the split-phase inverter circuit according to the modulation signal.

[0158] In some embodiments, the AC side current difference determination module 1102 is also used to determine the phase angle of each phase on the AC side according to the AC side voltage; determine the DC side target active current according to the DC side voltage and the first coefficient; and determine the AC side target active current according to the phase angle and the DC side target active current.

[0159] In some embodiments, the AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and the AC side current difference determination module 1102 is also used to phase-lock the first split-phase AC voltage through a phase-locked loop to obtain a first phase-locked angle; and phase-lock the second split-phase AC voltage through the phase-locked loop to obtain a second phase-locked angle.

[0160] In some embodiments, the DC side voltage includes a first DC voltage and a second DC voltage, the first DC voltage corresponds to a first split-phase AC voltage, and the second DC voltage corresponds to a second split-phase AC voltage. The split-phase inverter circuit control device 1100 also includes a filtering module 1105, and the filtering module 1105 is used to perform software filtering on the first DC voltage to obtain a first filtered DC voltage; and perform software filtering on the second DC voltage to obtain a second filtered DC voltage.

[0161] In some embodiments, the AC side current difference determination module 1102 is also used to determine the target DC voltage based on the DC side voltage and the second coefficient; determine the filtered voltage sum of the first filtered DC voltage and the second filtered DC voltage, and determine the DC side target active current based on the difference between the target DC voltage and the filtered voltage sum and the first coefficient.

[0162] In some embodiments, the AC side current difference determination module 1102 is also used to determine the equalizing current based on the equalizing voltage and a third coefficient, wherein the equalizing voltage includes the difference between the first filtered DC voltage and the second filtered DC voltage; determine the AC side target current based on the sum of the AC side target active current and the equalizing current; and determine the AC side current difference based on the difference between the AC side target current and the AC side current.

[0163] In some embodiments, the signal modulation module 1103 is also used to input the AC side current difference into the quasi-proportional resonant controller, and output a basic gain after calculation according to a bilinear variation transfer function in the quasi-proportional resonant controller; determine an additional gain according to the AC side voltage difference and a fourth coefficient; and determine the gain value according to the basic gain and the additional gain.

[0164] In some embodiments, the signal modulation module 1103 is also used to determine that the sum of the AC side voltage and the gain value is an AC transient voltage; determine the duty cycle of each phase on the AC side according to the AC transient voltage and the DC side voltage; and determine the on-time of each level voltage as the modulation signal according to the duty cycle of each phase on the AC side and a preset modulation period.

[0165] In some embodiments, the split-phase inverter circuit control device 1100 also includes a voltage tracking module 1106, which is used to determine the average DC voltage of multiple DC side voltages within a target period based on a sampling number, and the sampling number includes the number of times the DC side voltage is collected within the sampling period; determine the difference between the average DC voltage and the target DC voltage; if the difference is less than a preset threshold, reduce the target DC voltage by a first threshold; if the difference is greater than or equal to the preset threshold, increase the target DC voltage by a second threshold.

[0166] In some embodiments, the split-phase inverter circuit control device 1100 also includes a power tracking module 1107, and the power tracking module 1107 includes determining the circuit output power before the change and the circuit output power after the change when the target DC voltage changes, and the target DC voltage change includes reducing or increasing the target DC voltage; if the circuit output power before the change is greater than the circuit output power after the change, then reducing the target DC voltage by a third threshold; if the circuit output power before the change is less than the circuit output power after the change, then increasing the target DC voltage by a fourth threshold.

[0167] Each module in the above-mentioned split-phase inverter circuit control device 1100 can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0168] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a split-phase inverter circuit control method is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0169] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0170] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the split-phase inverter circuit control method described in any of the above embodiments are implemented.

[0171] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps of the split-phase inverter circuit control method described in any of the above embodiments.

[0172] In traditional technology, the split-phase inverter circuit may generate DC ripple voltage when converting DC power into AC power, which affects the power quality and equipment life. Figure 8As shown, the present application provides a split-phase inverter circuit, which includes a DC power supply Udc, a voltage divider module, a first inverter module, a second inverter module, a first AC bus Ua and a second AC bus Uc. The voltage divider module is connected in parallel with the DC power supply Udc, and the voltage divider module is also connected to the first inverter module and the second inverter module respectively. The first inverter module is also connected to the first AC bus Ua, and the second inverter module is also connected to the second AC bus Uc, wherein,

[0173] The voltage dividing module includes a first voltage dividing unit and a second voltage dividing unit connected in series. The first voltage dividing unit may include a first capacitor C1, and the second voltage dividing unit may include a second capacitor C2. The first voltage dividing unit and the second voltage dividing unit may play the role of voltage dividing and supporting.

[0174] The first inverter module includes a first transistor IGBT1, a second transistor IGBT2, a third transistor IGBT3 and a fourth transistor IGBT4, the emitter of the first transistor IGBT1 is connected to the first end of the first voltage divider unit, the collector of the first transistor IGBT1 is respectively connected to the first AC bus Ua, the emitter of the second transistor IGBT2, and the collector of the fourth transistor IGBT4, the collector of the second transistor IGBT2 is connected to the first end of the second voltage divider unit, the emitter of the fourth transistor IGBT4 is connected to the emitter of the third transistor IGBT3, and the collector of the third transistor IGBT3 is respectively connected to the second end of the first voltage divider unit and the second end of the second voltage divider unit;

[0175] The second inverter module includes a fifth transistor IGBT5, a sixth transistor IGBT6, a seventh transistor IGBT7 and an eighth transistor IGBT8, the emitter of the fifth transistor IGBT5 is connected to the first end of the first voltage divider unit, the collector of the fifth transistor IGBT5 is respectively connected to the emitter of the sixth transistor IGBT6, the collector of the eighth transistor IGBT8 and the second AC bus Uc, the collector of the sixth transistor IGBT6 is connected to the first end of the second voltage divider unit, the emitter of the eighth transistor IGBT8 is connected to the emitter of the seventh transistor IGBT7, and the collector of the seventh transistor IGBT7 is respectively connected to the second end of the first voltage divider unit and the second end of the second voltage divider unit.

[0176] In some embodiments, the split-phase inverter circuit further includes a first filtering module, a second filtering module and a neutral line, wherein the neutral line is connected to the second end of the first voltage dividing unit and the second end of the second voltage dividing unit, respectively.

[0177] The first filtering module includes a first inductor L1, a second inductor L2 and a third capacitor C3, wherein a first end of the first inductor L1 is respectively connected to the collector of the first transistor IGBT1, the emitter of the second transistor IGBT2 and the collector of the fourth transistor IGBT4, a second end of the first inductor L1 is respectively connected to a first end of the second inductor L2 and a first end of the third capacitor C3, a second end of the second inductor L2 is connected to the first AC bus Ua, and a second end of the third capacitor C3 is connected to the neutral line;

[0178] The first filtering module includes a third inductor L3, a fourth inductor L4 and a fourth capacitor C4. The first end of the third inductor L3 is respectively connected to the collector of the fifth transistor IGBT5, the emitter of the sixth transistor IGBT6 and the collector of the eighth transistor IGBT8. The second end of the third inductor L3 is respectively connected to the first end of the fourth inductor L4 and the first end of the fourth capacitor C4. The second end of the fourth inductor L4 is connected to the second AC bus Uc. The second end of the fourth capacitor C4 is respectively connected to the neutral line and the second end of the third capacitor C3.

[0179] In the embodiment of the present application, the AC side voltages Ua and Uc and the AC side currents Ia and Ic can be sampled. The embodiment of the present application performs split-phase inverter output through a T-type three-level inverter module, and by increasing the intermediate level (i.e., 0 level), the amplitude of the output voltage change is reduced, and the voltage fluctuation caused by each transistor operation is small, thereby reducing the DC ripple voltage. In addition, the split-phase inverter circuit provided in the embodiment of the present application requires a smaller grid-side inductance, a smaller DC ripple voltage, and a smaller DC support capacitor, which can effectively improve the power quality and equipment life.

[0180] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with general skills in the technical field to which this application belongs. The words "one", "a", "the", "these" and the like in this application do not indicate a quantitative limitation, and they may be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone. Generally, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0181] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0182] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0183] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A split-phase inverter circuit control method, characterized in that: The method comprises: Obtaining a DC side voltage, an AC side voltage, and an AC side current of a split-phase inverter circuit; Determine an AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient, and determine an AC side current difference according to the AC side current and the AC side target active current; wherein determining the AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient includes: Determine the phase angle of each phase on the AC side according to the AC side voltage; determine the target active current on the DC side according to the DC side voltage and the first coefficient; determine the target active current on the AC side according to the phase angle and the target active current on the DC side; The AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and determining the phase angle of each phase of the AC side according to the AC side voltage includes: Phase-locking the first split-phase AC voltage through a phase-locked loop to obtain a first phase-locked angle; phase-locking the second split-phase AC voltage through the phase-locked loop to obtain a second phase-locked angle; The AC side current difference is converted into a gain value by a quasi-proportional resonant controller, and a modulation signal is determined according to the DC side voltage, the AC side voltage and the gain value; wherein the converting the AC side current difference into a gain value by a quasi-proportional resonant controller comprises: Input the AC side current difference into the quasi-proportional resonant controller, and output a basic gain after calculation according to a bilinear change transfer function in the quasi-proportional resonant controller; determine an additional gain according to the AC side voltage difference and a fourth coefficient; determine the gain value according to the basic gain and the additional gain; The determining of the modulation signal according to the DC side voltage, the AC side voltage and the gain value comprises: Determine the sum of the AC side voltage and the gain value as the AC transient voltage; determine the duty cycle of each phase on the AC side according to the AC transient voltage and the DC side voltage; determine the on-time of each level voltage as the modulation signal according to the duty cycle of each phase on the AC side and a preset modulation period; The on and off of the switching device in the split-phase inverter circuit is controlled according to the modulation signal.

2. The method according to claim 1, characterized in that Before determining the DC side target active current according to the DC side voltage and the first coefficient, the method further includes: Dividing the DC side voltage to obtain a first DC voltage and a second DC voltage; Performing software filtering on the first DC voltage to obtain a first filtered DC voltage; The second DC voltage is software filtered to obtain a second filtered DC voltage.

3. The method according to claim 2, characterized in that The determining of the DC side target active current according to the DC side voltage and the first coefficient comprises: Determine a target DC voltage according to the DC side voltage and a second coefficient; A filtered voltage sum of the first filtered DC voltage and the second filtered DC voltage is determined, and the DC side target active current is determined according to a difference between the target DC voltage and the filtered voltage sum and the first coefficient.

4. The method according to claim 2, characterized in that: The determining the AC side current difference according to the AC side current and the AC side target active current comprises: Determine a voltage-sharing current according to a voltage-sharing voltage and a third coefficient, wherein the voltage-sharing voltage includes a difference between the first filtered DC voltage and the second filtered DC voltage; Determine the target current on the AC side according to the sum of the target active current on the AC side and the voltage-sharing current; The AC side current difference is determined according to the AC side target current and the difference between the AC side current.

5. The method according to claim 3, characterized in that: After controlling the on and off of the switch device in the split-phase inverter circuit according to the modulation signal, the method further includes: Determine an average DC voltage of a plurality of the DC link voltages within a target period according to a sampling quantity, wherein the sampling quantity includes the number of times the DC link voltage is collected within a sampling period; determining a difference between the average DC voltage and the target DC voltage; If the difference is less than a preset threshold, reducing the target DC voltage by a first threshold; If the difference is greater than or equal to the preset threshold, the target DC voltage is increased by a second threshold.

6. The method according to claim 5, characterized in that The method further comprises: determining the circuit output power before and after the change when the target DC voltage changes, wherein the target DC voltage change includes reducing or increasing the target DC voltage; If the circuit output power before the change is greater than the circuit output power after the change, reducing the target DC voltage by a third threshold; If the circuit output power before the change is less than the circuit output power after the change, the target DC voltage is increased by a fourth threshold.

7. A split-phase inverter circuit control device, characterized in that: The device comprises: A data acquisition module, used to acquire the DC side voltage, AC side voltage and AC side current of the split-phase inverter circuit; An AC side current difference determination module is used to determine an AC side target active current according to the AC side voltage, the DC side voltage and a first coefficient, and to determine an AC side current difference according to the AC side current and the AC side target active current; wherein determining the AC side target active current according to the AC side voltage, the DC side voltage and the first coefficient includes: Determine the phase angle of each phase on the AC side according to the AC side voltage; determine the target active current on the DC side according to the DC side voltage and the first coefficient; determine the target active current on the AC side according to the phase angle and the target active current on the DC side; The AC side voltage includes a first split-phase AC voltage and a second split-phase AC voltage, and determining the phase angle of each phase of the AC side according to the AC side voltage includes: Phase-locking the first split-phase AC voltage through a phase-locked loop to obtain a first phase-locked angle; phase-locking the second split-phase AC voltage through the phase-locked loop to obtain a second phase-locked angle; A signal modulation module, used for converting the AC side current difference into a gain value through a quasi-proportional resonant controller, and determining a modulation signal according to the DC side voltage, the AC side voltage and the gain value; wherein, converting the AC side current difference into a gain value through a quasi-proportional resonant controller comprises: Input the AC side current difference into the quasi-proportional resonant controller, and output a basic gain after calculation according to a bilinear change transfer function in the quasi-proportional resonant controller; determine an additional gain according to the AC side voltage difference and a fourth coefficient; determine the gain value according to the basic gain and the additional gain; The determining of the modulation signal according to the DC side voltage, the AC side voltage and the gain value comprises: Determine the sum of the AC side voltage and the gain value as the AC transient voltage; determine the duty cycle of each phase on the AC side according to the AC transient voltage and the DC side voltage; determine the on-time of each level voltage as the modulation signal according to the duty cycle of each phase on the AC side and a preset modulation period; A control module is used to control the on and off of the switch device in the split-phase inverter circuit according to the modulation signal.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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