High-gain photovoltaic inverter power supply device and control method and related equipment

Abstract

The present application provides a high-gain photovoltaic inverter power supply device and its control method and related equipment, which can adopt coupled inductor technology to improve the gain of the DC converter unit therein and reduce the turns ratio and leakage inductance of the high-frequency transformer in the photovoltaic inverter power supply device; and an implicit lossless absorption circuit can recover the leakage inductance energy of the photovoltaic inverter power supply device and clamp the turn-off voltage spike of the power switch tube; and the error value obtained by comparing the grid current sampling value with the given reference current value can be sent to the PI controller to correct the peak reference current in real time, effectively improve the control accuracy of the photovoltaic inverter power supply device control system, and ensure the dynamic characteristics of the system; it can work in a critical conduction mode and obtain a switching frequency lower than that of a flyback inverter of a traditional photovoltaic inverter power supply device. The high-gain photovoltaic inverter power supply device also has soft switching characteristics such as zero voltage switching and zero current switching, and can achieve high conversion efficiency and high efficiency over a wide load range.

Description

Technical Field

[0001] The present application relates to the fields of power electronics technology and renewable energy and power generation technology, and in particular to a high-gain photovoltaic inverter power supply device and a control method and related equipment thereof. Background Art

[0002] In the field of photovoltaic micro-inverter power generation, due to work efficiency considerations, most inverters use a two-stage conversion circuit based on a virtual DC bus structure. The front-stage circuit of this inverter mainly realizes the MPPT function of the photovoltaic module and the DC sinusoidal full-wave modulation of the module voltage, while the rear-stage circuit is an industrial frequency commutation circuit to realize the AC sinusoidal conversion of the DC sinusoidal full-wave.

[0003] Traditional photovoltaic inverter power supply devices mainly use flyback inverters, which have simple topology and control strategies and are therefore very popular. However, their high step-up ratio is only achieved by relying on a large turns ratio, which leads to high leakage inductance in the photovoltaic inverter power supply device. Excessive leakage inductance of the inverter weakens the working efficiency of the photovoltaic inverter power supply device. Summary of the invention

[0004] The present application aims to solve at least one of the above-mentioned technical defects. In view of this, the present application provides a high-gain photovoltaic inverter power supply device and its control method and related equipment, which are used to solve the technical defect of low inverter working efficiency in the photovoltaic inverter power supply device in the prior art.

[0005] A high-gain photovoltaic inverter power supply device, the high-gain photovoltaic inverter power supply device comprising: a main circuit and a control circuit; wherein the main circuit is connected to the control circuit; the main circuit comprises an industrial frequency commutation circuit and at least one DC converter unit; wherein each of the DC converter units comprises a plurality of photovoltaic components, a plurality of decoupling capacitors, a plurality of high-frequency transformers, a plurality of resonant capacitors, a plurality of resonant inductors, a plurality of filter capacitors and a plurality of power switch tubes; the number of photovoltaic components, decoupling capacitors, high-frequency transformers, resonant capacitors and resonant inductors of each DC converter unit is consistent, and each The number of filter capacitors and power switch tubes of each DC converter unit is consistent and is three times the number of photovoltaic modules of each DC converter unit; wherein the DC converter unit is used to convert the DC waveform of each photovoltaic module into a DC sine full wave; when the number of decoupling capacitors of each DC converter unit is 1, each DC converter unit includes a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube and a third power switch tube; wherein the first end of the decoupling capacitor is respectively connected to the first end of the photovoltaic module of the DC converter unit , the first input end of the primary winding of the high-frequency transformer of the DC converter unit is connected; the second end of the decoupling capacitor is respectively connected to the second end of the photovoltaic component, the source of the first power switch tube, the second end of the resonant capacitor, the second end of the resonant inductor and the second end of the second filter capacitor to form the second output end of the DC converter unit; the second input end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor; the first output end of the secondary winding of the high-frequency transformer is connected to the source of the third power switch tube The first end of the third filter capacitor is connected to the drain of the third power switch tube to form the first output end of the DC converter unit, wherein the first output end of the secondary winding of the high-frequency transformer of the DC converter unit and the second input end of the primary winding of the high-frequency transformer of the DC converter unit form the same-name end; the source of the second power switch tube is connected to the first end of the resonant inductor and the second end of the first filter capacitor; the drain of the second power switch tube is connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor and the second end of the third filter capacitor;

[0006] The power frequency commutation circuit includes a plurality of power switch tubes, a plurality of filter capacitors and a plurality of filter inductors, wherein the number of the filter capacitors and the filter inductors of the power frequency commutation circuit are the same, and the number of the power switch tubes of the power frequency commutation circuit is four times the number of the filter capacitors of the power frequency commutation circuit;

[0007] When the number of filter capacitors in the power frequency commutation circuit is 1, the power frequency commutation circuit includes a fourth power switch tube, a fifth power switch tube, a sixth power switch tube and a seventh power switch tube; the filter capacitor and the filter inductor of the power frequency commutation circuit are respectively connected to each power switch tube;

[0008] The drain of the fourth power switch tube of the power frequency commutation circuit is connected to the drain of the fifth power switch tube of the power frequency commutation circuit to form a first input end of the power frequency commutation circuit;

[0009] The source of the fourth power switch tube of the power frequency commutation circuit is connected to the drain of the sixth power switch tube of the power frequency commutation circuit, the first end of the filter capacitor of the power frequency commutation circuit and the input end of the filter inductor of the power frequency commutation circuit; the output end of the filter inductor of the power frequency commutation circuit is connected to the first end of the power grid; the source of the fifth switch tube of the power frequency commutation circuit is connected to the drain of the seventh switch tube of the power frequency commutation circuit, the second end of the filter capacitor of the power frequency commutation circuit and the second end of the power grid; the source of the sixth switch tube of the power frequency commutation circuit is connected to the source of the seventh switch tube of the power frequency commutation circuit, forming the second input end of the power frequency commutation circuit; wherein the power frequency commutation circuit is used to convert a DC sinusoidal full wave into an AC sinusoidal waveform; The control circuit includes a sampling circuit, an analog signal detection circuit, an industrial frequency commutation drive circuit, a drive circuit and a digital controller, wherein the digital controller is respectively connected to the sampling circuit, the analog signal detection circuit, the drive circuit and the industrial frequency commutation drive circuit, wherein the sampling circuit is responsible for collecting grid voltage, grid current, voltage and current signals of each photovoltaic component, the analog signal detection circuit is responsible for collecting the primary current signal and the secondary current zero-crossing signal of the high-frequency transformer, and the control circuit assists each photovoltaic component to generate electricity at maximum power and assists the main circuit to generate AC sinusoidal current through the signals collected by each circuit and the digital controller, so as to inject the electric energy generated by each photovoltaic component into the grid.

[0010] Preferably, when the connection mode of the plurality of DC converter units included in the main circuit is parallel connection, the connection mode of each DC converter unit in the main circuit and the power frequency commutation circuit includes:

[0011] The first output end of each DC converter unit is connected in sequence and then connected to the first input end of the power frequency commutation circuit; the second output end of each DC converter unit is connected in sequence and then connected to the second input end of the power frequency commutation circuit.

[0012] Preferably, when a plurality of the DC converter units in the main circuit are connected in series, the connection between each DC converter unit in the main circuit and the power frequency commutation circuit includes:

[0013] The first output end of the first target DC converter unit is connected to the first input end of the industrial frequency commutation circuit, wherein the first target DC converter unit is the first DC converter unit among the DC converter units connected in series in the main circuit; the second output end of the second target DC converter unit is connected to the second input end of the industrial frequency commutation circuit, wherein the last DC converter unit among the DC converter units connected in series in the main circuit is the second target DC converter unit.

[0014] Preferably, the sampling circuit includes a grid voltage sampling circuit, a grid current sampling circuit, several photovoltaic module voltage sampling circuits, and several photovoltaic module current sampling circuits; wherein the number of photovoltaic module voltage sampling circuits and photovoltaic module current sampling circuits of the sampling circuit is consistent with the number of the DC converter units; the analog signal detection circuit includes a primary current signal detection circuit and a secondary current zero-crossing signal detection circuit; the power frequency commutation drive circuit includes several power frequency commutation drive sub-circuits for each power switch tube of the power frequency commutation circuit, wherein the number of the power frequency commutation drive sub-circuits is consistent with the number of power switch tubes of the power frequency commutation circuit, and each of the power frequency commutation drive sub-circuits corresponds to each power switch tube of the power frequency commutation circuit; the drive circuit includes several drive sub-circuits for each power switch tube of the DC converter unit, wherein the number of the drive sub-circuits is consistent with the number of the power switch tubes of the power frequency commutation circuit. The number of power switch tubes of the DC converter unit is consistent, and each of the driving sub-circuits corresponds to each power switch tube of the DC converter unit; the digital controller includes a grid voltage and current sampling module, a photovoltaic module voltage and current sampling module, a PI controller module, a peak current feedforward controller module, a critical mode controller module, a maximum power point tracking algorithm module, a synchronous rectification controller module, an industrial frequency commutation PWM module, a maximum value module and a phase-locked loop module, wherein the grid voltage and current sampling module is connected to the phase-locked loop module and the maximum value module, and the phase-locked loop module is responsible for processing the grid voltage sampling value collected by the grid voltage and current sampling module to generate an industrial frequency driving signal of each power switch tube of the industrial frequency commutation circuit, and driving each power switch tube of the industrial frequency commutation circuit according to the generated industrial frequency driving signal of each power switch tube of the industrial frequency commutation circuit;

[0015] The photovoltaic module voltage and current sampling module is connected to the maximum power point tracking algorithm module to transmit the collected signals to the maximum power point tracking algorithm module for processing;

[0016] The maximum power point tracking algorithm module is connected to the peak current feedforward controller module to transmit the signal collected by the photovoltaic module voltage and current sampling module to the peak current feedforward controller module for processing;

[0017] The critical mode controller module is connected to the peak current feedforward controller module and the PI controller module to collect the signal output by the peak current feedforward controller module and the signal output by the PI controller module as a basis for determining whether to turn off or turn on the first power switch tube of the DC converter unit, wherein the critical mode controller module compares a preset reference current with the primary current detected by the primary current signal detection circuit, and if the detected primary current is greater than or equal to the preset reference current, then the first power switch tube of the DC converter unit is turned off, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module, wherein the input of the PI controller module is the error value obtained by comparing the grid current sampling value with the given reference current value; when the secondary current obtained by the secondary current zero-crossing signal detection circuit is less than or equal to 0, the first power switch tube of the DC converter unit is turned on;

[0018] The synchronous rectification controller module is connected to the driving circuit, and is responsible for collecting drain-source voltage signals of each power switch tube of the DC converter unit to obtain information on the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and respectively generates high-frequency driving signals for the second power switch tube and the third power switch tube of the DC converter unit, and drives the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency driving signals;

[0019] The power frequency commutation PWM module is connected to the power frequency commutation drive circuit to collect signals from the power frequency commutation drive circuit.

[0020] A control method for a high-gain photovoltaic inverter power supply device is applied to any of the high-gain photovoltaic inverter power supply devices described above, the method comprising:

[0021] Compare the preset reference current with the primary current detected by the primary current signal detection circuit; if the detected primary current is greater than or equal to the preset reference current, turn off the first power switch tube of the DC converter unit, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module; when the secondary current obtained by the secondary current zero-crossing signal detection circuit is less than or equal to 0, turn on the first power switch tube of the DC converter unit; use a phase-locked loop to process the sampling value of the grid voltage, and generate the fourth power switch tube, the fifth power switch tube, and the sixth power switch tube of the power frequency commutation circuit respectively. The invention relates to a method for controlling the power supply of a first power switch tube and a second power switch tube of the power frequency commutation circuit, wherein the first power switch tube and the seventh power switch tube are respectively driven by the power frequency drive signals of the power switch tubes of the power frequency commutation circuit, and the second power switch tubes of the power frequency commutation circuit are respectively driven according to the power frequency drive signals of the power switch tubes of the power frequency commutation circuit; a synchronous rectifier controller is used to collect the drain-source voltage signals of the power switch tubes of the DC converter unit to obtain the information of the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and high-frequency drive signals of the second power switch tube and the third power switch tube of the DC converter unit are respectively generated, and the second power switch tube and the third power switch tube of the DC converter unit are driven according to the generated high-frequency drive signals.

[0022] A control device for a high-gain photovoltaic inverter power supply device, comprising:

[0023] A first processing unit is configured to compare a preset reference current with a primary current detected by a primary current signal detection circuit, and to turn off a first power switch tube of a DC converter unit if the detected primary current is greater than or equal to the preset reference current, wherein the preset reference current is the sum of a current determined by a peak current feedforward controller module and a current determined by a PI controller module, and when the number of decoupling capacitors of each DC converter unit is 1, each DC converter unit includes a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube, and a third power switch tube; wherein a first end of the decoupling capacitor is respectively connected to a first end of a photovoltaic component of the DC converter unit and a first input end of a primary winding of a high-frequency transformer of the DC converter unit; a second end of the decoupling capacitor is respectively connected to a second end of the photovoltaic component, a source of the first power switch tube, a second end of the resonant capacitor, and a second end of the resonant inductor. The first end of the secondary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor to form the second output end of the DC converter unit; the second input end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor; the first output end of the secondary winding of the high-frequency transformer is connected to the source of the third power switch tube; the first end of the third filter capacitor is connected to the drain of the third power switch tube to form the first output end of the DC converter unit, wherein the first output end of the secondary winding of the high-frequency transformer of the DC converter unit and the second input end of the primary winding of the high-frequency transformer of the DC converter unit constitute the same-name end; the source of the second power switch tube is connected to the first end of the resonant inductor and the second end of the first filter capacitor; the drain of the second power switch tube is connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor, and the second end of the third filter capacitor;

[0024] A second processing unit, configured to turn on the first power switch tube of the DC converter unit when the secondary current acquired by the secondary current zero-crossing signal detection circuit is less than or equal to 0;

[0025] a third processing unit, configured to process the sampling value of the grid voltage by using a phase-locked loop, to generate power frequency drive signals of a fourth power switch tube, a fifth power switch tube, a sixth power switch tube, and a seventh power switch tube of the power frequency commutation circuit, respectively, and to drive each power switch tube of the power frequency commutation circuit according to the power frequency drive signal of each power switch tube of the power frequency commutation circuit;

[0026] The fourth processing unit is used to collect the drain-source voltage signals of each power switch tube of the DC converter unit by using a synchronous rectification controller to obtain the information of the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and respectively generate high-frequency driving signals for the second power switch tube and the third power switch tube of the DC converter unit, and drive the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency driving signals.

[0027] A control device for a high-gain photovoltaic inverter power supply device comprises: one or more processors, and a memory; the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the high-gain photovoltaic inverter power supply device control method as described above are implemented.

[0028] A readable storage medium stores computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors implement the steps of the control method of the high-gain photovoltaic inverter power supply device as described above.

[0029] It can be seen from the technical solutions introduced above that by adopting the coupled inductor technology, not only the gain of the DC converter unit of the photovoltaic inverter power supply device can be improved, but also the turns ratio and leakage inductance of the high-frequency transformer of the photovoltaic inverter power supply device can be reduced; and the implicit lossless absorption circuit can not only recover the leakage inductance energy of the photovoltaic inverter power supply device, but also clamp the turn-off voltage spike of the power switch tube; and the high-gain photovoltaic inverter power supply device can compare the grid current sampling value with the given reference current value to obtain the error value and send it to the PI controller to realize real-time correction of the peak reference current, effectively improve the control accuracy of the photovoltaic inverter power supply device control system, and ensure the dynamic characteristics of the system; and the high-gain photovoltaic inverter power supply device provided by the present application can operate in the critical conduction mode, and can obtain a switching frequency lower than that of the flyback inverter of the traditional photovoltaic inverter power supply device. In addition, the high-gain photovoltaic inverter power supply device provided by the present application also has soft switching characteristics such as zero voltage switching and zero current switching, which can achieve high conversion efficiency and high efficiency over a wide load range. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1A structural diagram of a high-efficiency high-gain photovoltaic inverter power supply device provided in this application;

[0032] Figure 2 A flow chart of a control method for a high-gain photovoltaic inverter power supply device provided in the present application;

[0033] Figure 3 A main circuit diagram structure diagram of a high-gain photovoltaic inverter power supply device provided in this application;

[0034] Figure 4 A schematic diagram of the structure of a digital controller for a high-gain photovoltaic inverter power supply device provided in this application;

[0035] Figure 5 The main working waveform diagram of a high-gain photovoltaic inverter power supply device provided in this application within a half-power frequency cycle;

[0036] Figure 6 Six circuit modal diagrams within one switching cycle of a high-gain photovoltaic inverter power supply device provided in this application;

[0037] Figure 7-Figure 11 They are respectively a modal diagram corresponding to a high-frequency working waveform of a high-gain photovoltaic inverter power supply device provided in the present application;

[0038] Fig.12 A topological diagram of a 1-torr-n parallel high-gain photovoltaic inverter power supply device provided in this application;

[0039] Fig.13 A topological diagram of a 1-torr-n series high-gain photovoltaic inverter power supply device provided in this application;

[0040] Fig.14 A schematic diagram of the structure of a control device for a high-gain photovoltaic inverter power supply device as an example of this application;

[0041] Fig.15 This is a hardware structure block diagram of a control device for a high-gain photovoltaic inverter power supply device disclosed in this application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] In view of the fact that most of the current photovoltaic inverters are difficult to adapt to complex and changing business needs, the applicant has studied a high-gain photovoltaic inverter power supply device and its control method and related equipment.

[0044] The control method of the high-gain photovoltaic inverter power supply device provided in the present application can be used in many general or special computing device environments or configurations, such as digital signal processors (DSPs), field programmable gate arrays (FPGAs), single-chip microcomputers, etc.

[0045] An embodiment of the present application provides a control method for a high-gain photovoltaic inverter power supply device. The method can be applied to various photovoltaic inverter management systems, and can also be applied to various computer terminals or smart terminals. The execution subject can be a processor or server of the computer terminal or smart terminal.

[0046] Combine the following Figure 1 , a high-gain photovoltaic inverter power supply device that can achieve high efficiency given in an embodiment of the present application is introduced, and the high-gain photovoltaic inverter power supply device may include: a main circuit and a control circuit; wherein the main circuit may be connected to the control circuit; the main circuit may include an industrial frequency commutation circuit and at least one DC converter unit; wherein the DC converter unit of the main circuit may be used to convert the DC waveform of each photovoltaic component into a DC sinusoidal full wave; wherein each DC converter unit in the main circuit may include a number of photovoltaic components, a number of decoupling capacitors, a number of high-frequency transformers, a number of resonant capacitors, a number of resonant inductors, a number of filter capacitors and a number of power switch tubes; the number of photovoltaic components, decoupling capacitors, high-frequency transformers, resonant capacitors and resonant inductors of each DC converter unit in the main circuit is consistent, and the number of filter capacitors of each DC converter unit is consistent with the number of power switch tubes and is three times the number of photovoltaic components of each DC converter unit; the decoupling capacitor of each DC converter unit in the main circuit is respectively connected to its photovoltaic component, high-frequency transformer, resonant capacitor, resonant inductor, each filter capacitor and each power switch tube to form a first output end and a second output end of each DC converter unit.

[0047] For example, in actual application, the number of decoupling capacitors of the DC converter unit of the high-gain photovoltaic inverter power supply device can be set according to the actual application scenario. For example, the number of decoupling capacitors of the DC converter unit of the high-gain photovoltaic inverter power supply device provided in the present application can be n, where n is a positive integer greater than or equal to 1.

[0048] For example, when the number of decoupling capacitors in each DC converter unit of the high-gain photovoltaic inverter power supply device provided in the present application is 1, each DC converter unit can include 3 filter capacitors and 3 power switch tubes, which may be a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube and a third power switch tube, respectively. Each filter capacitor and each power switch tube of each DC converter unit are respectively connected to the decoupling capacitor of the DC converter unit.

[0049] For example, when the number of decoupling capacitors in each DC converter unit is 1, each DC converter unit includes a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube and a third power switch tube; wherein the second end of the decoupling capacitor is connected to the source of the first power switch tube and the second end of the second filter capacitor; the second input end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube and the first end of the first filter capacitor; the first output end of the secondary winding of the high-frequency transformer is connected to the drain of the third power switch tube; the first end of the third filter capacitor is connected to the source of the third power switch tube; the drain of the second power switch tube is connected to the second end of the first filter capacitor; the source of the second power switch tube is connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor and the second end of the third filter capacitor.

[0050] Based on this, the decoupling capacitor of each DC converter unit is respectively connected to its photovoltaic module, high-frequency transformer, resonant capacitor, resonant inductor, each filter capacitor and each power switch tube to form the first output end and the second output end of each DC converter unit, which may include the following process:

[0051] The first end of the decoupling capacitor of the DC converter unit is respectively connected to the first end of the photovoltaic component of the DC converter unit and the first input end of the primary winding of the high-frequency transformer of the DC converter unit; the second end of the decoupling capacitor of the DC converter unit is respectively connected to the second end of the photovoltaic component of the DC converter unit, the source of the first power switch tube of the DC converter unit, the second end of the resonant capacitor of the DC converter unit, the second end of the resonant inductor of the DC converter unit and the second end of the second filter capacitor of the DC converter unit to form the second output end of the DC converter unit; the second input end of the primary winding of the high-frequency transformer of the DC converter unit can be respectively connected to the drain of the first power switch tube of the DC converter unit, the first end of the first filter capacitor of the DC converter unit and the first end of the resonant capacitor of the DC converter unit; wherein, the DC converter The first output end of the secondary winding of the high-frequency transformer of the converter unit and the second input end of the primary winding of the high-frequency transformer of the DC converter unit constitute the same-name end, the first output end of the secondary winding of the high-frequency transformer of the DC converter unit can be connected to the source of the third power switch tube of the DC converter unit, and the first end of the third filter capacitor of the DC converter unit is connected to the drain of the third power switch tube of the DC converter unit to constitute the first output end of the DC converter unit; the source of the second power switch tube of the DC converter unit can be connected to the first end of the resonant inductor of the DC converter unit and the second end of the first filter capacitor, and the drain of the second power switch tube of the DC converter unit can be connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor of the DC converter unit, and the second end of the third filter capacitor of the DC converter unit. Among them, the industrial frequency commutation circuit of the main circuit can be used to convert a DC full-wave sine wave into an AC sine waveform; the industrial frequency commutation circuit of the main circuit can include a plurality of power switching tubes, a plurality of filter capacitors and a plurality of filter inductors; wherein, the number of filter capacitors and filter inductors of the industrial frequency commutation circuit of the main circuit is the same, and the number of power switching tubes of the industrial frequency commutation circuit can be four times the number of filter capacitors of the industrial frequency commutation circuit; each power switching tube of the industrial frequency commutation circuit is correspondingly connected to the filter capacitor and the filter inductor to form a first input terminal and a second input terminal of the industrial frequency commutation circuit.

[0052] For example, in actual application, the number of filter capacitors of the power frequency commutation circuit of the high-gain photovoltaic inverter power supply device can be set according to the actual application scenario.

[0053] For example, the number of filter capacitors in the industrial frequency commutation circuit of the high-gain photovoltaic inverter power supply device provided in the present application may be n, where n is a positive integer greater than or equal to 1.

[0054] For example, further, when the number of filter capacitors of the power frequency commutation circuit is 1, the power frequency commutation circuit may include 4 power switch tubes, which may be a fourth power switch tube, a fifth power switch tube, a sixth power switch tube, and a seventh power switch tube respectively; the filter capacitor and the filter inductor of the power frequency commutation circuit may be connected to each power switch tube respectively; based on this, each power switch tube of the power frequency commutation circuit is connected to the filter capacitor and the filter inductor correspondingly to form the first input terminal and the second input terminal of the power frequency commutation circuit, which may include the following process:

[0055] The drain of the fourth power switch tube of the power frequency commutation circuit can be connected to the drain of the fifth power switch tube of the power frequency commutation circuit to form the first input end of the power frequency commutation circuit; the source of the fourth power switch tube of the power frequency commutation circuit can be connected to the drain of the sixth power switch tube of the power frequency commutation circuit, and the first end of the filter capacitor of the power frequency commutation circuit can be connected to the input end of the filter inductor of the power frequency commutation circuit; the output end of the filter inductor of the power frequency commutation circuit can be connected to the first end of the power grid; the source of the fifth switch tube of the power frequency commutation circuit can be connected to the drain of the seventh switch tube of the power frequency commutation circuit, the second end of the filter capacitor of the power frequency commutation circuit and the second end of the power grid; the source of the sixth switch tube of the power frequency commutation circuit can be connected to the source of the seventh switch tube of the power frequency commutation circuit to form the second input end of the power frequency commutation circuit.

[0056] In actual application, the number of DC converter units of the high-gain photovoltaic inverter power supply device can be set according to the actual application scenario. For example, the number of DC converter units of the high-gain photovoltaic inverter power supply device provided in the present application can be n, where n is a positive integer greater than or equal to 1.

[0057] For example, when the main circuit includes a photovoltaic component, a decoupling capacitor, and a high-frequency transformer, the main circuit may include seven power switching tubes, a resonant capacitor, a resonant inductor, four filter capacitors, and a filter inductor.

[0058] In actual application, when the number of the DC converter units is at least two, the DC converter units of the high-gain photovoltaic inverter power supply device may be connected in parallel or in series.

[0059] For example, when the connection mode of several DC converter units included in the main circuit is parallel connection, the connection mode of each DC converter unit in the main circuit and the industrial frequency commutation circuit may include as follows: the first output end of each DC converter unit is connected in sequence and then connected to the first input end of the industrial frequency commutation circuit; the second output end of each DC converter unit is connected in sequence and then connected to the second input end of the industrial frequency commutation circuit.

[0060] When the connection mode of several DC converter units in the main circuit is series connection, the connection mode of each DC converter unit in the main circuit and the power frequency commutation circuit may include the following: the first output end of the first target DC converter unit is connected to the first input end of the power frequency commutation circuit, wherein the first target DC converter unit may be the first DC converter unit among the DC converter units connected in series in the main circuit; the second output end of the first target DC converter unit is connected in series with the first input end of the next DC converter unit connected in series with it, and so on, the series connection mode of several DC converters in the main circuit is the same; the last DC converter unit among the DC converter units connected in series in the main circuit is the second target DC converter unit, and the second output end of the second target DC converter unit is connected to the second input end of the power frequency commutation circuit.

[0061] Among them, the control circuit of the high-gain photovoltaic inverter power supply device provided in the present application can be used to assist each photovoltaic component to generate electricity at maximum power and assist the main circuit to generate AC sinusoidal current, so as to inject the electric energy generated by each photovoltaic component into the power grid. The control circuit may include a sampling circuit, an analog signal detection circuit, an industrial frequency commutation drive circuit, a drive circuit and a digital controller, wherein the digital controller may be connected to the sampling circuit, the analog signal detection circuit, the drive circuit and the industrial frequency commutation drive circuit respectively; the sampling circuit may include a grid voltage sampling circuit, a grid current sampling circuit, a plurality of photovoltaic module voltage sampling circuits and a plurality of photovoltaic module current sampling circuits; wherein the number of photovoltaic module voltage sampling circuits and photovoltaic module current sampling circuits of the sampling circuit is consistent with the number of DC converter units; the analog signal detection circuit may include a primary current signal detection circuit and a secondary current zero-crossing signal detection circuit; the industrial frequency commutation drive circuit includes a plurality of industrial frequency commutation drive sub-circuits for each power switch tube of the industrial frequency commutation circuit, wherein the number of the industrial frequency commutation drive sub-circuits is consistent with the number of the power switch tubes of the industrial frequency commutation circuit, and each industrial frequency commutation drive sub-circuit corresponds to each power switch tube of the industrial frequency commutation circuit; the drive circuit may The invention comprises a plurality of driving subcircuits for each power switch tube of the DC converter unit, wherein the number of the driving subcircuits is consistent with the number of the power switch tubes of the DC converter unit, and each driving subcircuit is in a corresponding relationship with each power switch tube of the DC converter unit; the digital controller may include a grid voltage and current sampling module, a photovoltaic module voltage and current sampling module, a PI controller module, a peak current feedforward controller module, a critical mode controller module, a maximum power point tracking algorithm module, a synchronous rectification controller module, an industrial frequency commutation PWM module, a maximum value module and a phase-locked loop module, wherein the grid voltage and current sampling module is connected to the phase-locked loop module and the maximum value module, and the phase-locked loop module is responsible for processing the grid voltage sampling value collected by the grid voltage and current sampling module to generate the industrial frequency driving signal of each power switch tube of the industrial frequency commutation circuit, and drives each power switch tube of the industrial frequency commutation circuit according to the industrial frequency driving signal of each power switch tube of the industrial frequency commutation circuit generated;

[0062] The photovoltaic module voltage and current sampling module is connected to the maximum power point tracking algorithm module to transmit the collected signals to the maximum power point tracking algorithm module for processing;

[0063] The maximum power point tracking algorithm module is connected to the peak current feedforward controller module to transmit the signal collected by the photovoltaic module voltage and current sampling module to the peak current feedforward controller module for processing;

[0064] The critical mode controller module is connected to the peak current feedforward controller module and the PI controller module to collect the signal output by the peak current feedforward controller module and the signal output by the PI controller module as the basis for determining whether to turn off or turn on the first power switch tube of the DC converter unit, wherein the critical mode controller module compares the preset reference current with the primary current detected by the primary current signal detection circuit, and if the detected primary current is greater than or equal to the preset reference current, the first power switch tube of the DC converter unit is turned off, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module, wherein the input of the PI controller module can be the error value obtained by comparing the grid current sampling value with the given reference current value; when the secondary current obtained by the secondary current zero-crossing signal detection circuit is less than or equal to 0, the first power switch tube of the DC converter unit is turned on;

[0065] The synchronous rectification controller module is connected to the driving circuit, and is responsible for collecting drain-source voltage signals of each power switch tube of the DC converter unit to obtain information on the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and respectively generates high-frequency driving signals for the second power switch tube and the third power switch tube of the DC converter unit, and drives the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency driving signals;

[0066] The power frequency phase-commutation PWM module is connected to the power frequency phase-commutation drive circuit to collect the signal of the power frequency phase-commutation drive circuit.

[0067] Combine the following Figure 2 , introduces the process of the method for controlling the high-gain photovoltaic inverter power supply device provided by the present application given in the embodiment of the present application, such as Figure 2 As shown, the process can include the following steps:

[0068] Step S101, compare the preset reference current with the primary current detected by the primary current signal detection circuit, and if the detected primary current is greater than or equal to the preset reference current, turn off the first power switch tube of the DC converter unit. The preset reference current can be set to the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module.

[0069] Step S102: when the secondary current acquired by the secondary current zero-crossing signal detection circuit is less than or equal to 0, turning on the first power switch tube of the DC converter unit.

[0070] Step S103, using a phase-locked loop to process the sampled value of the grid voltage, respectively generating power frequency drive signals for the fourth power switch tube, the fifth power switch tube, the sixth power switch tube and the seventh power switch tube of the power frequency commutation circuit, and respectively driving each power switch tube of the power frequency commutation circuit according to the power frequency drive signal of each power switch tube of the power frequency commutation circuit.

[0071] Step S104: using a synchronous rectification controller to collect drain-source voltage signals of each power switch tube of the DC converter unit to obtain information on the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, respectively generating high-frequency drive signals for the second power switch tube and the third power switch tube of the DC converter unit, and driving the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency drive signals.

[0072] For example, in actual application, the present application can couple the flyback primary inductor with the SEPIC inductor based on a virtual DC bus structure, stack the flyback output and the SEPIC output in series, and adopt a composite control strategy of a peak current feedforward controller combined with a PI controller and a synchronous rectification control strategy to provide a flyback-SEPIC high-gain photovoltaic inverter power supply device.

[0073] See also Figure 3 and Figure 4 , Figure 3 A schematic diagram of the main circuit structure of a flyback-SEPIC high-gain photovoltaic inverter power supply device provided in this application; Figure 4 A schematic diagram of the digital controller structure of a flyback-SEPIC high-gain photovoltaic inverter power supply device provided in this application;

[0074] From the above introduction, it can be seen that the high-gain photovoltaic inverter power supply device provided in this application may include a main circuit and a control circuit, such as Figure 3 As shown, the main circuit includes a photovoltaic module, a decoupling capacitor, a high-frequency transformer, seven power switch tubes, a resonant capacitor, a resonant inductor, four filter capacitors and a filter inductor. The connection relationship of each component can be as follows:

[0075] In the main circuit of the high-gain photovoltaic inverter power supply device provided in this application, the decoupling capacitor The first end can be connected to the photovoltaic module The first end of the high-frequency transformer T primary winding and the first input end; decoupling capacitor The second end of the photovoltaic module The second end of the first power switch tube The source and resonant capacitor The second end of the resonant inductor The second end of the second filter capacitor The second end of the sixth power switch tube The source and seventh power switch tube The second input end of the primary winding of the high-frequency transformer T can be connected to the source of the first power switch tube The drain, first filter capacitor The first end and the resonant capacitor The first end of the secondary winding of the high-frequency transformer T is connected; the same-name end formed by the first output end of the secondary winding of the high-frequency transformer T and the second input end of the primary winding of the high-frequency transformer T can be connected to the third power switch tube The drain connection of the third filter capacitor The first end of the third power switch tube The source of the fourth power switch tube The drain and the fifth power switch tube The drain connection of the second power switch tube The drain and resonant inductance The first end and the first filter capacitor The second end of the second power switch tube is connected; The source of the high frequency transformer T is connected to the second output terminal of the secondary winding and the second filter capacitor The first end of the third filter capacitor The second end of the fourth power switch tube is connected; The source of the sixth power switch tube The drain, the fourth filter capacitor The first end and the first filter inductor The input terminal is connected; the first filter inductor The output end of the fifth power switch is connected to the first end of the power grid. The source of the seventh power switch tube The drain, the fourth filter capacitor The second end of the power grid is connected to the second end of the power grid.

[0076] The control circuit of the flyback-SEPIC high-gain photovoltaic inverter power supply device provided in the present application may include a sampling circuit, an analog signal detection circuit, an industrial frequency commutation drive circuit, a drive circuit and a digital controller; wherein the sampling circuit may include a grid voltage sampling circuit, a grid current sampling circuit, a photovoltaic module voltage sampling circuit and a photovoltaic module current sampling circuit; the analog signal detection circuit includes a primary current signal detection circuit and a secondary current zero-crossing signal detection circuit; the industrial frequency commutation drive circuit includes a fourth power switch tube The drive circuit and the fifth power switch tube The drive circuit and the sixth power switch tube The drive circuit and the seventh power switch tube The driving circuit may include a first power switch tube The driving circuit and the second power switch tube The drive circuit and the third power switch tube The digital controller may include a grid voltage and current sampling module, a photovoltaic module voltage and current sampling module, a PI controller module, a peak current feedforward controller module, a critical mode controller module, a maximum power point tracking algorithm module, a synchronous rectification controller module, a power frequency commutation PWM module, a maximum value module and a phase-locked loop module.

[0077] See also Figure 3 , 4 and Figure 5 It can be seen that the high-gain photovoltaic inverter power supply device provided by the present application operates in the critical conduction mode in half the power frequency cycle. Figure 5 middle, Indicates the voltage of the virtual DC bus; Indicates the preset reference current, Represents the primary current; Represents the first power switch tube; Indicates the first power switch The drain-source voltage of Represents the current flowing through the resonant inductor The current; Indicates the phase; in actual application, it can be compared with the preset reference current With the primary current signal Obtained the first power switch tube The shutdown signal is transmitted through the secondary current zero crossing signal get The opening signal.

[0078] For example, a preset reference current may be compared with the primary current detected by the primary current signal detection circuit. If it is determined that the primary current detected by the primary current signal detection circuit is greater than or equal to the preset reference current, the first power switch tube of the DC converter unit is turned off. The preset reference current can be set to the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module. When the secondary current zero-crossing signal detection circuit obtains the secondary current less than or equal to 0, the first power switch tube of the DC converter unit can be turned on. .

[0079] The sampling value of the grid voltage can be processed by a phase-locked loop to generate the fourth power switch tube , the fifth power switch tube 、The sixth power switch tube And the seventh power switch tube For example, a phase-locked loop can be used to process the sampling value of the grid voltage to generate the fourth power switch tube of the power frequency commutation circuit. , the fifth power switch tube 、The sixth power switch tube And the seventh power switch tube The power frequency driving signal is received, and each power switch tube of the power frequency commutation circuit is driven according to the power frequency driving signal of each power switch tube of the power frequency commutation circuit.

[0080] The synchronous rectifier controller can collect the drain-source voltage signals of each power switch tube of the DC converter unit to determine the information of the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current; for example, the second power switch tube of the DC converter unit can be collected. The drain-source voltage signal of the DC converter unit is obtained to obtain the information of the conduction of the second power switch tube body diode and the zero crossing of the secondary current, and the second switch tube of the DC converter unit is generated respectively. And the third switch The high-frequency driving signal is generated, and the second switch tube of the DC converter unit is driven according to the generated high-frequency driving signal. And the third switch The control strategy is to combine the peak current feedforward controller module with the PI controller module to generate the reference current required by the critical mode controller module. , where the peak current feedforward controller module can be used to control the reference current Pre-adjustment can enhance the system's anti-interference ability and relieve the control pressure of the PI controller module; the PI controller module can correct the reference current in real time , effectively improving the control accuracy of the system and ensuring the dynamic characteristics of the system. Among them, the expression of the current determined by the peak current feedforward controller module is as follows (1):

[0081] (1);

[0082] Among them, in formula (1), represents the reference current; It can represent the peak value of the sinusoidal reference current; It can indicate the peak value of the grid voltage; It can indicate the voltage of photovoltaic modules; It can represent the transformer turns ratio; It can represent the grid voltage phase angle;

[0083] The PI controller module usually adopts the traditional PI plus pole form, which is expressed as follows (2):

[0084] (2);

[0085] In formula (2), is the proportionality coefficient; is the integration coefficient; For the turning cycle; is the gain function of the PI controller; is a complex domain independent variable.

[0086] Based on the various driving signals generated above, the working state of the flyback-SEPIC high-gain photovoltaic inverter power supply device provided by the present application within a half-power frequency cycle can be as follows:

[0087] The first power switch , the second power switch tube And the third power switch tube They all work at high frequency to convert the DC voltage of the photovoltaic module into a DC full-wave sinusoidal voltage. , where the second power switch tube And the third power switch tube The switching state is the same as that of the first power switch tube Assuming that the half-cycle of the AC power grid is positive or negative, the fourth power switch tube And the seventh power switch tube Long on or long off, the fifth power switch tube And the sixth power switch tube Long-off or long-on to achieve DC full-wave sinusoidal voltage Converted into the standard sinusoidal voltage required by the power grid. , the second power switch tube And the third power switch tube The operating frequency is not fixed. At the center of the sine wave, the operating frequency is the smallest. The closer to the zero point of the sine wave, the larger the operating frequency. As the power decreases, the overall operating frequency tends to increase.

[0088] See also Figure 6 , the flyback-SEPIC high-gain photovoltaic inverter power supply device provided by the present application can include six working modes in a complete switching cycle; in addition, for ease of understanding, Figure 3 The power frequency commutation circuit and the power grid are equivalent to a DC full-wave sine wave (mantou wave) source. Figure 6 In Indicates the switching cycle.

[0089] like Figure 7-Figure 11 As shown, Figure 7-Figure 11The dotted line frame part represents the high-frequency transformer T;

[0090] (1) ~ Time period: Current flows along the path such as Figure 7 As shown by the bold black line in At this moment, the main power switch tube In the on state, the input power starts to supply the excitation inductor and leakage inductance Charging, primary current Starting from zero, it increases linearly until time Shutdown, primary current The slope of is: On the other hand, the filter capacitor Resonant Inductor Charging, the corresponding mode is as follows Figure 7 shown.

[0091] (2) ~ Time period: Current flows along the path such as Figure 8 As shown by the bold black line in At this moment, the main power switch tube Turn off, magnetizing inductance , leakage inductance and resonant capacitor The three resonate, and the resonant frequency is: . Primary current The main power switch tube remains almost unchanged. The drain-source voltage rises slowly and linearly, and the corresponding mode is as follows Figure 8 As shown, Slows down the power switch The rising slope of the drain-source voltage makes It has the characteristic of "zero voltage shutdown", which effectively reduces the shutdown loss; in addition, the filter capacitor through Continue to resonant inductor Charge.

[0092] (3) ~ Time period: Current flows along the path such as Fig. 9 As shown by the bold black line in At this moment, the power switch tube and conduction, stored in the excitation inductance The energy is released to the output end. The energy flow path includes the secondary winding of the high-frequency transformer and the power switch tube. , and through the filter capacitor (Towards Charging) and power switch tube ; In addition, the stored in the resonant inductor The energy is then transferred through the switch tube Release to the output terminal. Figure 6 The high-frequency oscillation waveform in the figure shows that the leakage inductance With resonant capacitor and filter capacitors High-frequency resonance will occur, and the leakage inductance energy will be recycled to the output end. The peak voltage is also effectively suppressed, and the corresponding modal diagram is shown in Fig. 9 shown.

[0093] (4) ~ Time period: Current flows along the path such as Fig. 9 As shown by the bold black line in At this moment, the filter capacitor current And the primary current It crosses zero and becomes negative, and is stored in The energy in the resonant inductor starts to be fed back to the input power supply end; Continue to provide energy to the output end, because its inductance value is large enough, so the resonant inductor current In continuous mode, it will not cross zero; the output current With slope Gradually decays, is the virtual DC bus voltage, is the number of high-gain photovoltaic inverter power devices connected in series or in parallel. When the decay reaches zero, the mode ends. and The shutdown drive signal can achieve zero current shutdown, and the corresponding modal diagram is as follows Fig. 9 As shown. According to Kirchhoff's current law, the output current , filter capacitor current and the resonant inductor current The relationship between them is: .

[0094] (5) ~ Time period: Current flows along the path such as Fig.10 As shown by the bold black line in At this moment, the power switch tube and Zero current shutdown, with Figure 8 The modes shown are similar, the resonant capacitor With excitation inductance and leakage inductance Resonance occurs, the main power switch tube Drain-Source Voltage Gradually decays, time, decays to zero, during this time interval, It can be expressed as: To ensure the main power switch Implementation of zero voltage soft switching, delay time Should be greater than On the other hand, the filter capacitor Start to resonate inductor Charging, resonant inductor current Slowly rises linearly, and the corresponding modal diagram is as follows Fig.10 shown.

[0095] (6) ~ Time period: Current flows along the path such as Fig.11 As shown by the bold black line in After the time, the primary current Reverse flow through the main switch tube The body diode , is clamped to 0. At this time, adding a driving signal can achieve Zero voltage switching, At this moment, the high-gain photovoltaic inverter power supply device enters the next switching cycle, and the corresponding mode is as follows Fig.11 shown.

[0096] Fig.12 The one-torr-n parallel flyback-SEPIC high-gain photovoltaic inverter power supply device shown in the figure is Fig.13 The control strategy and basic working principle of the one-torr-n series flyback-SEPIC high-gain photovoltaic inverter power supply device shown in the figure are similar to those Figure 2-Figure 3 as well as Figure 7-Figure 11 The illustrated embodiment has a similar process.

[0097] From the above introduction, it can be seen that the high-gain photovoltaic inverter power supply device provided by this application can adopt coupled inductor technology, which improves the gain of the converter, reduces the turns ratio and leakage inductance of the transformer, and improves the efficiency of the converter; the two converter outputs are stacked, providing a lossless absorption circuit, reducing voltage stress, and recovering leakage inductance energy; the inductor current critical conduction mode is adopted, providing zero voltage soft switching and zero current soft switching, reducing the switching loss of the inverter; the peak current feedforward controller is combined with the PI controller to enhance the system's anti-interference ability and dynamic response ability, while ensuring the stability of the system; the synchronous rectification technology is adopted to achieve bidirectional energy flow, adapting to the development requirements of future smart grids. The one-to-n parallel or series topology structure adopted breaks through the technical bottleneck of the traditional virtual DC bus, realizes the free expansion of the inverter power, further improves the efficiency of the inverter, and reduces the cost per unit power.

[0098] The control device of the high-gain photovoltaic inverter power supply device provided by the present application is described below. The control device of the high-gain photovoltaic inverter power supply device described below and the control method of the high-gain photovoltaic inverter power supply device described above can be referred to each other. Fig.14 , Fig.14 Schematic diagram of the control device structure of a high-gain photovoltaic inverter power supply device disclosed in the embodiment of the present application. Fig.14 As shown, the control device of the high-gain photovoltaic inverter power supply device may include:

[0099] The first processing unit 101 is used to compare a preset reference current with the primary current detected by the primary current signal detection circuit. If the detected primary current is greater than or equal to the preset reference current, the first power switch tube of the DC converter unit is turned off, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module. When the number of decoupling capacitors of each DC converter unit is 1, each DC converter unit includes a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube and a third power switch tube; wherein the first end of the decoupling capacitor is respectively connected to the first end of the photovoltaic component of the DC converter unit and the first input end of the primary winding of the high-frequency transformer of the DC converter unit; the second end of the decoupling capacitor is respectively connected to the second end of the photovoltaic component, the source of the first power switch tube, the second end of the resonant capacitor, the second end of the resonant inductor, and the third end of the resonant inductor. The second end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor to form the second output end of the DC converter unit; the second input end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor; the first output end of the secondary winding of the high-frequency transformer is connected to the source of the third power switch tube; the first end of the third filter capacitor is connected to the drain of the third power switch tube to form the first output end of the DC converter unit, wherein the first output end of the secondary winding of the high-frequency transformer of the DC converter unit and the second input end of the primary winding of the high-frequency transformer of the DC converter unit constitute the same-name end; the source of the second power switch tube is connected to the first end of the resonant inductor and the second end of the first filter capacitor; the drain of the second power switch tube is connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor, and the second end of the third filter capacitor;

[0100] A second processing unit 102, configured to turn on the first power switch tube of the DC converter unit when the secondary current obtained by the secondary current zero-crossing signal detection circuit is less than or equal to 0;

[0101] The third processing unit 103 is used to process the sampling value of the grid voltage by using a phase-locked loop, generate power frequency drive signals of the fourth power switch tube, the fifth power switch tube, the sixth power switch tube and the seventh power switch tube of the power frequency commutation circuit respectively, and drive each power switch tube of the power frequency commutation circuit according to the power frequency drive signal of each power switch tube of the power frequency commutation circuit respectively;

[0102] The fourth processing unit 104 is used to collect drain-source voltage signals of each power switch tube of the DC converter unit by using a synchronous rectification controller to obtain information on the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and respectively generate high-frequency drive signals for the second power switch tube and the third power switch tube of the DC converter unit, and drive the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency drive signals.

[0103] It can be seen from the technical solutions introduced above that the control device of the high-gain photovoltaic inverter power supply device provided by the present application can adopt coupled inductor technology, which can not only improve the gain of the DC converter unit, but also reduce the turns ratio and leakage inductance of the high-frequency transformer; and the implicit lossless absorption circuit can not only recover the leakage inductance energy, but also clamp the turn-off voltage spike of the power switch tube; and the control device of the high-gain photovoltaic inverter power supply device provided by the present application can compare the grid current sampling value with the given reference current value to obtain the error value and send it to the PI controller to realize real-time correction of the peak reference current, effectively improve the control accuracy of the system, and ensure the dynamic characteristics of the system; and the control device of the high-gain photovoltaic inverter power supply device provided by the present application can operate in the critical conduction mode, and can obtain a switching frequency lower than that of the traditional flyback inverter. In addition, the control device of the high-gain photovoltaic inverter power supply device provided by the present application also has soft switching characteristics such as zero voltage switching and zero current switching, which can achieve high conversion efficiency and high efficiency over a wide load range.

[0104] Among them, the specific processing flow of each unit included in the control device of the above-mentioned high-gain photovoltaic inverter power supply device can refer to the relevant introduction of the control method of the high-gain photovoltaic inverter power supply device in the previous text, and will not be repeated here.

[0105] The control device of the high-gain photovoltaic inverter power supply device provided in the present application can be applied to control equipment of the high-gain photovoltaic inverter power supply device, such as a terminal: a computer, etc.

[0106] Optional, Fig.15 The hardware structure block diagram of the control device of the high-gain photovoltaic inverter power supply device is shown. Fig.15, the hardware structure of the control device of the high-gain photovoltaic inverter power supply device may include: at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4. In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3 and the communication bus 4 is at least one, and the processor 1, the communication interface 2 and the memory 3 communicate with each other through the communication bus 4. The processor 1 may be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiment of the present application; the memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory; wherein the memory stores a program, and the processor can call the program stored in the memory, and the program is used to: implement each processing flow in the control scheme of the aforementioned terminal high-gain photovoltaic inverter power supply device.

[0107] An embodiment of the present application also provides a readable storage medium, which can store a program suitable for execution by a processor, wherein the program is used to: implement various processing flows of the aforementioned terminal in the control scheme of the high-gain photovoltaic inverter power supply device.

[0108] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0109] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present application. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. The various embodiments can be combined with each other. Therefore, the present application will not be limited to the embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A high-gain photovoltaic inverter power supply device, characterized in that: The high-gain photovoltaic inverter power supply device comprises: a main circuit and a control circuit; Wherein, the main circuit is connected to the control circuit; The main circuit includes an industrial frequency commutation circuit and at least one DC converter unit; Each of the DC converter units includes a plurality of photovoltaic components, a plurality of decoupling capacitors, a plurality of high-frequency transformers, a plurality of resonant capacitors, a plurality of resonant inductors, a plurality of filter capacitors and a plurality of power switch tubes; the number of photovoltaic components, decoupling capacitors, high-frequency transformers, resonant capacitors and resonant inductors of each DC converter unit is consistent, the number of filter capacitors and power switch tubes of each DC converter unit is consistent and is three times the number of photovoltaic components of each DC converter unit; the DC converter unit is used to convert the DC waveform of each photovoltaic component into a DC full-sine wave; When the number of decoupling capacitors of each DC converter unit is 1, each DC converter unit includes a first filter capacitor, a second filter capacitor, a third filter capacitor, a first power switch tube, a second power switch tube and a third power switch tube; Wherein, the first end of the decoupling capacitor is respectively connected to the first end of the photovoltaic component of the DC converter unit and the first input end of the primary winding of the high-frequency transformer of the DC converter unit; The second end of the decoupling capacitor is respectively connected to the second end of the photovoltaic component, the source of the first power switch tube, the second end of the resonant capacitor, the second end of the resonant inductor and the second end of the second filter capacitor to form a second output end of the DC converter unit; The second input end of the primary winding of the high-frequency transformer is connected to the drain of the first power switch tube, the first end of the first filter capacitor, and the first end of the resonant capacitor; The first output end of the secondary winding of the high-frequency transformer is connected to the source of the third power switch tube; the first end of the third filter capacitor is connected to the drain of the third power switch tube to form the first output end of the DC converter unit, wherein the first output end of the secondary winding of the high-frequency transformer of the DC converter unit and the second input end of the primary winding of the high-frequency transformer of the DC converter unit form the same-name end; The source of the second power switch tube is connected to the first end of the resonant inductor and the second end of the first filter capacitor; The drain of the second power switch tube is connected to the second output end of the secondary winding of the high-frequency transformer, the first end of the second filter capacitor and the second end of the third filter capacitor; the power frequency commutation circuit includes a plurality of power switch tubes, a plurality of filter capacitors and a plurality of filter inductors, wherein the number of filter capacitors and filter inductors of the power frequency commutation circuit is the same, and the number of power switch tubes of the power frequency commutation circuit is four times the number of filter capacitors of the power frequency commutation circuit; when the number of filter capacitors of the power frequency commutation circuit is 1, the power frequency commutation circuit includes a fourth power switch tube, a fifth power switch tube, a sixth power switch tube and a seventh power switch tube; the filter capacitors and filter inductors of the power frequency commutation circuit are respectively connected to the corresponding power switch tubes; The drain of the fourth power switch tube of the power frequency commutation circuit is connected to the drain of the fifth power switch tube of the power frequency commutation circuit to form a first input end of the power frequency commutation circuit; The source of the fourth power switch tube of the power frequency commutation circuit is connected to the drain of the sixth power switch tube of the power frequency commutation circuit, the first end of the filter capacitor of the power frequency commutation circuit and the input end of the filter inductor of the power frequency commutation circuit; the output end of the filter inductor of the power frequency commutation circuit is connected to the first end of the power grid; the source of the fifth switch tube of the power frequency commutation circuit is connected to the drain of the seventh switch tube of the power frequency commutation circuit, the second end of the filter capacitor of the power frequency commutation circuit and the second end of the power grid; the source of the sixth switch tube of the power frequency commutation circuit is connected to the source of the seventh switch tube of the power frequency commutation circuit, forming the second input end of the power frequency commutation circuit; wherein the power frequency commutation circuit is used to convert a DC sinusoidal full wave into an AC sinusoidal waveform; The control circuit includes a sampling circuit, an analog signal detection circuit, an industrial frequency commutation drive circuit, a drive circuit and a digital controller, wherein the digital controller is respectively connected to the sampling circuit, the analog signal detection circuit, the drive circuit and the industrial frequency commutation drive circuit, wherein the sampling circuit is responsible for collecting grid voltage, grid current, voltage and current signals of each photovoltaic component, the analog signal detection circuit is responsible for collecting the primary current signal and the secondary current zero-crossing signal of the high-frequency transformer, and the control circuit assists each photovoltaic component to generate electricity at maximum power and assists the main circuit to generate AC sinusoidal current through the signals collected by each circuit and the digital controller, so as to inject the electric energy generated by each photovoltaic component into the grid.

2. The high-gain photovoltaic inverter power supply device according to claim 1, characterized in that: When the connection mode of the plurality of DC converter units included in the main circuit is parallel connection, the connection mode of each DC converter unit in the main circuit and the power frequency commutation circuit includes: The first output end of each of the DC converter units is connected in sequence and then connected to the first input end of the power frequency commutation circuit; The second output end of each of the DC converter units is connected in sequence and then connected to the second input end of the power frequency commutation circuit.

3. The high-gain photovoltaic inverter power supply device according to claim 1, characterized in that: When the connection mode of several DC converter units in the main circuit is series connection, the connection mode of each DC converter unit in the main circuit and the power frequency commutation circuit includes: A first output terminal of a first target DC converter unit is connected to a first input terminal of the power frequency commutation circuit, wherein the first target DC converter unit is the first DC converter unit among the DC converter units connected in series in the main circuit; The second output end of the second target DC converter unit is connected to the second input end of the industrial frequency commutation circuit, wherein the last DC converter unit among the DC converter units connected in series in the main circuit is the second target DC converter unit.

4. The high-gain photovoltaic inverter power supply device according to claim 1, characterized in that: The sampling circuit includes a grid voltage sampling circuit, a grid current sampling circuit, a plurality of photovoltaic module voltage sampling circuits, and a plurality of photovoltaic module current sampling circuits; wherein the number of photovoltaic module voltage sampling circuits and photovoltaic module current sampling circuits of the sampling circuit is consistent with the number of the DC converter units; The analog signal detection circuit includes a primary current signal detection circuit and a secondary current zero-crossing signal detection circuit; The power frequency commutation drive circuit comprises a plurality of power frequency commutation drive sub-circuits for each power switch tube of the power frequency commutation circuit, wherein the number of the power frequency commutation drive sub-circuits is consistent with the number of the power switch tubes of the power frequency commutation circuit, and each of the power frequency commutation drive sub-circuits is in a corresponding relationship with each power switch tube of the power frequency commutation circuit; The driving circuit includes a plurality of driving sub-circuits for each power switch tube of the DC converter unit, wherein the number of the driving sub-circuits is consistent with the number of the power switch tubes of the DC converter unit, and each of the driving sub-circuits is in a corresponding relationship with each power switch tube of the DC converter unit; The digital controller includes a grid voltage and current sampling module, a photovoltaic module voltage and current sampling module, a PI controller module, a peak current feedforward controller module, a critical mode controller module, a maximum power point tracking algorithm module, a synchronous rectification controller module, an industrial frequency commutation PWM module, a maximum value module and a phase-locked loop module, wherein the grid voltage and current sampling module is connected to the phase-locked loop module and the maximum value module, and the phase-locked loop module is responsible for processing the grid voltage sampling value collected by the grid voltage and current sampling module to generate an industrial frequency drive signal of each power switch tube of the industrial frequency commutation circuit, and driving each power switch tube of the industrial frequency commutation circuit according to the generated industrial frequency drive signal of each power switch tube of the industrial frequency commutation circuit; The photovoltaic module voltage and current sampling module is connected to the maximum power point tracking algorithm module to transmit the collected signals to the maximum power point tracking algorithm module for processing; The maximum power point tracking algorithm module is connected to the peak current feedforward controller module to transmit the signal collected by the photovoltaic module voltage and current sampling module to the peak current feedforward controller module for processing; The critical mode controller module is connected to the peak current feedforward controller module and the PI controller module to collect the signal output by the peak current feedforward controller module and the signal output by the PI controller module as a basis for determining whether to turn off or turn on the first power switch tube of the DC converter unit, wherein the critical mode controller module compares a preset reference current with the primary current detected by the primary current signal detection circuit, and if the detected primary current is greater than or equal to the preset reference current, then the first power switch tube of the DC converter unit is turned off, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module, wherein the input of the PI controller module is the error value obtained by comparing the grid current sampling value with the given reference current value; when the secondary current obtained by the secondary current zero-crossing signal detection circuit is less than or equal to 0, the first power switch tube of the DC converter unit is turned on; The synchronous rectification controller module is connected to the driving circuit, and is responsible for collecting drain-source voltage signals of each power switch tube of the DC converter unit to obtain information on the conduction of the body diode of each power switch tube of the DC converter unit and the zero crossing of the secondary current, and respectively generates high-frequency driving signals for the second power switch tube and the third power switch tube of the DC converter unit, and drives the second power switch tube and the third power switch tube of the DC converter unit according to the generated high-frequency driving signals; The power frequency commutation PWM module is connected to the power frequency commutation drive circuit to collect signals from the power frequency commutation drive circuit.

5. A control method for a high-gain photovoltaic inverter power supply device, characterized in that: Applied to the high-gain photovoltaic inverter power supply device according to any one of claim 4, the method comprising: Compare a preset reference current with a primary current detected by a primary current signal detection circuit, and if the detected primary current is greater than or equal to the preset reference current, turn off the first power switch tube of the DC converter unit, wherein the preset reference current is the sum of the current determined by the peak current feedforward controller module and the current determined by the PI controller module; When the secondary current acquired by the secondary current zero-crossing signal detection circuit is less than or equal to 0, turning on the first power switch tube of the DC converter unit; A phase-locked loop is used to process the sampling value of the grid voltage, and power-frequency drive signals of the fourth power switch tube, the fifth power switch tube, the sixth power switch tube and the seventh power switch tube of the power-frequency commutation circuit are generated respectively, and each power switch tube of the power-frequency commutation circuit is driven according to the power-frequency drive signal of each power switch tube of the power-frequency commutation circuit; A synchronous rectification controller is used to collect drain-source voltage signals of each power switch tube of a DC converter unit to obtain information on conduction of the body diode of each power switch tube of the DC converter unit and zero crossing of the secondary current, and high-frequency drive signals of the second power switch tube and the third power switch tube of the DC converter unit are respectively generated, and the second power switch tube and the third power switch tube of the DC converter unit are driven according to the generated high-frequency drive signals.

6. A control device for a high-gain photovoltaic inverter power supply device, characterized in that: include: one or more processors, and memory; The memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the control method of the high-gain photovoltaic inverter power supply device as claimed in claim 5 are implemented.

7. A readable storage medium, characterized in that: The readable storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors implement the steps of the control method of the high-gain photovoltaic inverter power supply device as claimed in claim 5.

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