Three-phase rectifier and output power disturbance method

Abstract

The invention relates to a three-phase rectifier and an output power disturbance method. The three-phase rectifier comprises: an AC-to-DC module, wherein a first end of the AC-to-DC module is connected with a three-phase power supply; the DC-to-DC module is connected with the AC-to-DC module, a first end of an inversion assembly in the DC-to-DC module is connected with a second end of the AC-to-DC module, and an upper bridge arm of the inversion assembly comprises a first inversion switch tube and a second inversion switch tube; a lower bridge arm of the inversion assembly comprises a third inversion switch tube and a fourth inversion switch tube, the drain electrode of the first inversion switch tube and the source electrode of the fourth inversion switch tube are both connected with the second end of the AC-to-DC module, and the source electrode of the first inversion switch tube is connected with the drain electrode of the second inversion switch tube. The source electrode of the second inversion switch tube is connected with the drain electrode of the third inversion switch tube, and the source electrode of the third inversion switch tube is connected with the drain electrode of the fourth inversion switch tube. According to the invention, the output voltage can be flexibly adjusted and rapid conversion of various requirements can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a three-phase rectifier and an output power disturbance method. Background Art

[0002] With the advancement of global energy transformation, the photovoltaic industry has become a leader in my country's strategic emerging industries. After more than ten years of development, photovoltaic technology has gradually matured, the industrial chain has gradually improved, and it has occupied an important position in the global market. my country is in a leading position in the world in terms of manufacturing capabilities, technical levels, application markets, and industrial system construction in the photovoltaic industry. As a key component in the photovoltaic power generation system, the inverter plays an important role in the process of converting and controlling solar power. With the continuous growth of the photovoltaic industry, the demand for inverters has also shown explosive growth. Manufacturers have stepped up their research and development efforts and continuously launched new products to enhance their market competitiveness.

[0003] Related technologies usually rely on photovoltaic simulation power supply systems. Photovoltaic simulation power supplies can simulate the voltage and current output of photovoltaic cells under real lighting conditions to verify the working performance of the inverter under different lighting, voltage and current conditions. These photovoltaic simulation power supplies usually have the functions of adjusting power, voltage and current, and can accurately simulate the output of photovoltaic cells under various environmental conditions.

[0004] However, in the relevant technologies, the existing photovoltaic simulation power supply is expensive, costing hundreds of thousands or even millions, which puts small and medium-sized enterprises under tremendous economic pressure, especially those with limited R&D budgets. In addition, the existing equipment lacks versatility and is difficult to adapt to photovoltaic cells of different power and voltage levels. It has poor scalability and cannot meet the rapidly changing market needs. In addition, the traditional photovoltaic simulation power supply is not adaptable enough to environmental factors and cannot fully simulate the battery performance under different climate and temperature conditions, affecting the accuracy and reliability of the test results. Therefore, there is an urgent need for a low-cost, flexible and scalable solution. Summary of the invention

[0005] Based on this, it is necessary to provide a three-phase rectifier and an output power disturbance method that can significantly improve the power factor and conversion efficiency and achieve a wider output power adjustment range.

[0006] In a first aspect, the present application provides a three-phase rectifier. The three-phase rectifier comprises:

[0007] An AC-to-DC module, wherein a first end of the AC-to-DC module is connected to a three-phase power supply and is used to convert the AC power output by the three-phase power supply into a constant DC power;

[0008] A DC-to-DC module, which is connected to an AC-to-DC module and is used for converting the converted constant DC power into voltage and outputting it. The DC-to-DC module includes an inverter component, a first end of the inverter component is connected to a second end of the AC-to-DC converter, the inverter component includes an inverter bridge arm, the inverter bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes a first inverter switch tube and a second inverter switch tube, the lower bridge arm includes a third inverter switch tube and a fourth inverter switch tube, the drain of the first inverter switch tube and the source of the fourth inverter switch tube are both connected to the second end of the AC-to-DC module, the source of the first inverter switch tube is connected to the drain of the second inverter switch tube, the source of the second inverter switch tube is connected to the drain of the third inverter switch tube, and the source of the third inverter switch tube is connected to the drain of the fourth inverter switch tube.

[0009] In an exemplary embodiment, the DC-to-DC module also includes a capacitor voltage divider component, which is respectively connected to the AC-to-DC module and the inverter component, and the capacitor voltage divider component includes a first voltage divider capacitor and a second voltage divider capacitor, the first end of the first voltage divider capacitor is connected to the drain of the first inverter switch tube, the second end of the first voltage divider capacitor is connected to the first end of the second voltage divider capacitor, and the second end of the second voltage divider capacitor is connected to the source of the fourth inverter switch tube.

[0010] In an exemplary embodiment, the DC-DC module further includes a resonant network, a first port of the resonant network is connected to the midpoint of the inverter bridge arm, and a second port of the resonant network is connected to the midpoint of the capacitor voltage divider component;

[0011] The resonant network includes a resonant capacitor and a resonant inductor, and the second end of the resonant inductor is connected to the first end of the resonant capacitor; wherein the first end of the resonant inductor is the first port of the resonant network.

[0012] In an exemplary embodiment, the DC-to-DC module also includes a transformer, wherein the first end of the positive coil of the transformer is connected to the third port of the resonant network, and the second end of the positive coil of the transformer is connected to the fourth port of the resonant network; wherein the second end of the resonant capacitor is the third port of the resonant network, and the third port and the fourth port are connected via a wire.

[0013] In an exemplary embodiment, the DC-to-DC module also includes a secondary rectifier component, which includes a first diode, a second diode, a third diode and a fourth diode. The first end of the secondary coil in the transformer is respectively connected to the anode of the first diode and the cathode of the third diode, the second end of the secondary coil in the transformer is respectively connected to the anode of the second diode and the cathode of the fourth diode, the cathode of the first diode and the cathode of the second diode are connected and serve as a first output terminal, and the anode of the third diode and the anode of the fourth diode are connected and serve as a second output terminal.

[0014] In an exemplary embodiment, the AC-DC module includes a rectifier, the rectifier includes a first bridge arm, a second bridge arm and a third bridge arm, and the first bridge arm, the second bridge arm and the third bridge arm have the same structure;

[0015] The first bridge arm includes a first switch, a fifth diode and a sixth diode, the cathode of the fifth diode and the anode of the sixth diode are both connected to the DC-DC module, and the first end of the first switch is connected to one phase of the three-phase power supply.

[0016] In an exemplary embodiment, the first switch includes a first rectifier switch tube, a first switch diode, a second switch diode, a third switch diode and a fourth switch diode, the cathode of the first switch diode and the cathode of the third switch diode are both connected to the source of the first rectifier switch tube, the anode of the second switch diode and the anode of the fourth switch diode are both connected to the drain of the first rectifier switch tube, the anode of the first switch diode is connected to the cathode of the second switch diode, and the anode of the third switch diode is connected to the cathode of the fourth switch diode.

[0017] In an exemplary embodiment, the AC-DC module further includes three first filter components, each of which has the same structure, and the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to a first filter component;

[0018] Each first filter component includes a first filter inductor, a second filter inductor and a first filter capacitor. The first end of the first filter inductor is connected to one phase of a three-phase power supply, the second end of the first filter inductor is connected to the first end of the second filter inductor and the first end of the first filter capacitor respectively, the second end of the second filter inductor in each first filter component is connected to the first end of the first switch in each bridge arm, and the second ends of the first filter capacitor in each first filter component are connected to each other.

[0019] In a second aspect, the present application further provides an output power disturbance method, which is applicable to the three-phase rectifier described in any of the above embodiments. The output power disturbance method comprises:

[0020] After adjusting the duty cycle based on the first disturbance scheme, obtaining a current output voltage and a current output current, and determining a current output power based on the current output voltage and the current output current;

[0021] Compare the current output power with the previous output power to obtain a first power comparison result;

[0022] When the first power comparison result is that the current output power is equal to the previous output power, the disturbance operation is terminated.

[0023] In an exemplary embodiment, after comparing the current output power with the previous output power to obtain a first power comparison result, the method further includes:

[0024] When the first power comparison result is that the current output power is less than the previous output power, the duty cycle is adjusted based on the second disturbance scheme, and the next output power is obtained;

[0025] Comparing the next output power with the current output power to obtain a second power comparison result;

[0026] When the second power comparison result is that the next output power is less than the current output power, the disturbance operation is continued until the next output power is equal to the current output power.

[0027] The above-mentioned three-phase rectifier and output power disturbance method effectively converts three-phase AC power into constant DC power through the AC-DC module, providing a stable power input for subsequent voltage conversion, and then utilizes the connected DC-DC module including the inverter bridge arm in the inverter component to flexibly adjust the output voltage and realize rapid conversion of various voltage and power requirements. It can also utilize the switch tube control of the inverter component to ensure the stability and efficiency of the current output, and can effectively cope with the output voltage and power fluctuations of photovoltaic cells in different environments, and reduce the economic pressure of product development and iteration. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are 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 creative work.

[0029] Figure 1 This is a circuit schematic diagram of a DC-DC converter module according to an embodiment of the present application;

[0030] Figure 2 A control diagram of an LCC power topology according to an embodiment of the present application;

[0031] Figure 3 A circuit connection diagram of an AC-to-DC module according to an embodiment of the present application;

[0032] Figure 4 A control principle diagram of a rectifier according to an embodiment of the present application;

[0033] Figure 5 A schematic diagram of a flow chart of an output power disturbance method according to an embodiment of the present application;

[0034] Figure 6 A control schematic diagram of a power disturbance observation method according to an embodiment of the present application;

[0035] Figure 7 It is a curve diagram of a PV simulation curve according to an embodiment of the present application.

[0036] Description of reference numerals:

[0037] Q1-first inverter switch tube, Q2-second inverter switch tube, Q3-third inverter switch tube, Q4-fourth inverter switch tube, C11-first voltage-dividing capacitor, C12-second voltage-dividing capacitor, Lr-resonant inductor, Cr-resonant capacitor, Lm1-positive coil, Lm2-secondary coil, D1-first diode, D2-second diode, D3-third diode, D4-fourth diode, C21-secondary filter capacitor;

[0038] D5-fifth diode, D6-sixth diode, Q3-first rectifier switch tube, D7-first switch diode, D8-second switch diode, D9-third switch diode, D10-fourth switch diode, L1-first filter inductor, L2-second filter inductor, C31-first filter capacitor, C32-second filter capacitor, C33-third filter capacitor. DETAILED DESCRIPTION

[0039] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0041] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0042] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0043] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0044] In some embodiments, the present application provides a three-phase rectifier, which includes an AC-to-DC module and a DC-to-DC module, wherein the first end of the DC-to-DC module is connected to a three-phase power supply, and the DC-to-DC module is connected to the AC-to-DC module.

[0045] See also Figure 1 , Figure 1 The circuit schematic diagram of the DC-DC module in an embodiment of the present application is shown. The DC-DC module includes an inverter component, which includes an inverter bridge arm, and the inverter bridge arm includes an upper bridge arm and a lower bridge arm. The upper bridge arm includes a first inverter switch tube Q1 and a second inverter switch tube Q2, and the source of the first inverter switch tube Q1 is connected to the drain of the second inverter switch tube Q2. The lower bridge arm includes a third inverter switch tube Q3 and a fourth inverter switch tube Q4, and the source of the third inverter switch tube Q3 is connected to the drain of the fourth inverter switch tube Q4. The drain of the first inverter switch tube Q1 and the source of the fourth inverter switch tube Q4 are both connected to the second end of the AC-DC module, and the source of the second inverter switch tube Q2 is connected to the drain of the third inverter switch tube Q3.

[0046] Use a PWM (pulse width modulation) controller to generate appropriate switching signals. Input the control signals to the gates of the four switches respectively to ensure that the first inverter switch Q1 and the second inverter switch Q2, the third inverter switch Q3 and the fourth inverter switch Q4 work alternately in sequence. The four switches are turned on and off in sequence through control signals. The first inverter switch Q1 and the second inverter switch Q2 are turned on alternately, and the third inverter switch Q3 and the fourth inverter switch Q4 are turned on alternately to ensure that the current flows in the correct direction. In addition, the frequency and duty cycle of the PWM signal can be adjusted according to the actual operating conditions to optimize the inverter performance.

[0047] In the above-mentioned three-phase rectifier, the three-phase AC power is effectively converted into constant DC power through the AC-DC module, providing a stable power input for the subsequent voltage conversion. Then, the output voltage can be flexibly adjusted by using the connected DC-DC module including the inverter bridge arm in the inverter component to achieve rapid conversion of various voltage and power requirements. The switch tube control of the inverter component can also be used to ensure the stability and efficiency of the current output, which can effectively cope with the output voltage and power fluctuations of photovoltaic cells in different environments, and reduce the economic pressure of product development and iteration.

[0048] In an exemplary embodiment, continue to refer to Figure 1 The DC-to-DC module also includes a capacitor voltage-dividing component, which is respectively connected to the AC-to-DC module and the inverter component. The capacitor voltage-dividing component includes a first voltage-dividing capacitor C11 and a second voltage-dividing capacitor C12. The first end of the first voltage-dividing capacitor C11 is connected to the drain of the first inverter switch tube Q1, the second end of the first voltage-dividing capacitor C11 is connected to the first end of the second voltage-dividing capacitor C12, and the second end of the second voltage-dividing capacitor C12 is connected to the source of the fourth inverter switch tube Q4.

[0049] The first voltage-dividing capacitor C11 distributes the high voltage of the inverter switch drain to the first end of the second voltage-dividing capacitor C12 through voltage division. The second end of the second voltage-dividing capacitor C12 is connected to the source of the fourth inverter switch Q4 to form a voltage division and current transmission path.

[0050] During operation, AC power is converted into DC power after passing through the AC-DC module, and the DC power is stabilized and regulated by the capacitor voltage divider component, thereby ensuring that the gate and source voltages of the inverter switch tube remain in the appropriate range when the inverter is working, avoiding excessively high or low voltages that may cause damage to the switch tube or unstable operation.

[0051] In an exemplary embodiment, continue to refer to Figure 1 The DC-DC module also includes a resonant network, a first port of the resonant network is connected to the midpoint of the inverter bridge arm, and a second port of the resonant network is connected to the midpoint of the capacitor voltage divider component.

[0052] The resonant network includes a resonant capacitor Cr and a resonant inductor Lr, and the second end of the resonant inductor Lr is connected to the first end of the resonant capacitor Cr. The first end of the resonant inductor Lr is the first port of the resonant network.

[0053] The current is converted into an AC signal through the inverter bridge arm and smoothly output to the capacitor voltage divider component through the resonant network to further adjust the output voltage and current. The working principle of the resonant network effectively optimizes the efficiency and stability of DC-to-DC conversion, ensuring the reliable operation of the system under different loads and working conditions.

[0054] In an exemplary embodiment, continue to refer to Figure 1 The DC-DC module also includes a transformer, a first end of the positive coil Lm1 of the transformer is connected to the third port of the resonant network, and a second end of the positive coil Lm1 of the transformer is connected to the fourth port of the resonant network.

[0055] The second end of the resonant capacitor Cr is the third port of the resonant network, and the third port is connected to the fourth port through a wire.

[0056] In an exemplary embodiment, continue to refer to Figure 1 The DC-DC module also includes a secondary rectifier component, which includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4. The first end of the secondary coil Lm2 in the transformer is respectively connected to the anode of the first diode D1 and the cathode of the third diode D3. The second end of the secondary coil Lm2 in the transformer is respectively connected to the anode of the second diode D2 and the cathode of the fourth diode D4. The cathode of the first diode D1 is connected to the cathode of the second diode D2 and serves as a first output terminal. The anode of the third diode D3 is connected to the anode of the fourth diode D4 and serves as a second output terminal.

[0057] When the voltage at the first terminal of the transformer secondary coil Lm2 is positive, the anode of the first diode D1 is connected to the terminal, forming forward conduction, and the cathode of the third diode D3 is also connected to the terminal, and the third diode D3 is turned on. At this time, the second diode D2 and the fourth diode D4 are in a reverse cutoff state. The current flows to the first output terminal through the first diode D1, and the third diode D3 is turned on, and the current flows to the second output terminal.

[0058] When the voltage at the second end of the transformer secondary coil Lm2 is positive, the anode of the second diode D2 is connected to the end, the second diode D2 is turned on, and the cathode of the fourth diode D4 is connected to the end, the fourth diode D4 is turned on. At this time, the first diode D1 and the third diode D3 are in a reverse cut-off state. The current flows to the first output end through the second diode D2, and the fourth diode D4 is turned on, and the current flows to the second output end.

[0059] In an exemplary embodiment, continue to refer to Figure 1 The secondary side rectifier component also includes a secondary side filter component, and the secondary side filter component includes a secondary side filter capacitor C21. The first end of the secondary side filter capacitor C21 is connected to the first output end, and the second end of the secondary side filter capacitor C21 is connected to the second output end.

[0060] The number of the secondary filter capacitors C21 can be two.

[0061] When the rectified current passes through the secondary rectifier component, the secondary filter capacitor C21 stores charge and filters out high-frequency noise and ripples, thereby reducing the fluctuation of the output voltage and ensuring that the voltage difference between the two ends is stable, thereby providing a smooth DC output.

[0062] In an exemplary embodiment, continue to refer to Figure 1 The present application provides a DC-to-DC module, which includes an inverter component, a capacitor voltage divider component, a resonant network, a transformer and a secondary rectifier component. The capacitor voltage divider component is respectively connected to the AC-to-DC module and the inverter component, the resonant network is respectively connected to the inverter component and the capacitor voltage divider component, the positive coil Lm1 of the transformer is connected to the resonant network, and the secondary network of the transformer is connected to the secondary rectifier component.

[0063] The capacitor voltage-dividing component includes a first voltage-dividing capacitor C11 and a second voltage-dividing capacitor C12. The first end of the first voltage-dividing capacitor C11 is connected to the drain of the first inverter switch tube Q1, the second end of the first voltage-dividing capacitor C11 is connected to the first end of the second voltage-dividing capacitor C12, and the second end of the second voltage-dividing capacitor C12 is connected to the source of the fourth inverter switch tube Q4.

[0064] The inverter assembly includes an inverter bridge arm, and the inverter bridge arm includes an upper bridge arm and a lower bridge arm. The upper bridge arm includes a first inverter switch tube Q1 and a second inverter switch tube Q2, and the source of the first inverter switch tube Q1 is connected to the drain of the second inverter switch tube Q2. The lower bridge arm includes a third inverter switch tube Q3 and a fourth inverter switch tube Q4, and the source of the third inverter switch tube Q3 is connected to the drain of the fourth inverter switch tube Q4. The drain of the first inverter switch tube Q1 and the source of the fourth inverter switch tube Q4 are both connected to the second end of the AC-DC module, and the source of the second inverter switch tube Q2 is connected to the drain of the third inverter switch tube Q3.

[0065] The first port of the resonant network is connected to the midpoint of the inverter bridge arm, and the second port of the resonant network is connected to the midpoint of the capacitor voltage divider component. The resonant network includes a resonant capacitor Cr and a resonant inductor Lr, and the second end of the resonant inductor Lr is connected to the first end of the resonant capacitor Cr. Among them, the first end of the resonant inductor Lr is the first port of the resonant network.

[0066] The secondary rectifier assembly includes a secondary rectifier assembly and a secondary filter assembly. The secondary rectifier assembly includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4. The first end of the secondary coil Lm2 in the transformer is connected to the anode of the first diode D1 and the cathode of the third diode D3 respectively. The second end of the secondary coil Lm2 in the transformer is connected to the anode of the second diode D2 and the cathode of the fourth diode D4 respectively. The cathode of the first diode D1 and the cathode of the second diode D2 are connected and serve as the first output terminal. The anode of the third diode D3 and the anode of the fourth diode D4 are connected and serve as the second output terminal. The secondary filter assembly includes a secondary filter capacitor C21. The first end of the secondary filter capacitor C21 is connected to the first output terminal, and the second end of the secondary filter capacitor C21 is connected to the second output terminal.

[0067] When the AC input signal enters through the AC to DC module, the switch tubes in the upper bridge arm and the lower bridge arm of the inverter component start working to control the switching of the current. The first inverter switch tube Q1 and the second inverter switch tube Q2 work together to convert the current into a high-frequency pulse signal. The first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 in the capacitor voltage-dividing component form a suitable voltage distribution according to the voltage-dividing principle to adjust the working state of the inverter switch tube. And the resonant inductor Lr and the resonant capacitor Cr in the resonant network optimize the voltage waveform, reduce switching losses, and enhance system efficiency through resonance.

[0068] The positive coil Lm1 of the transformer is connected to the resonant network to ensure that the voltage signal is converted and isolated by the transformer. The secondary rectifier component generates a DC current through four diodes. The capacitor in the secondary filter component smoothes the output current and ultimately provides a stable DC power supply to the load.

[0069] In an exemplary embodiment, see Figure 2 , Figure 2 : is a control diagram showing the LLC power topology in one embodiment of the present application. The LLC (Resonant Converter) consists of three loops, namely the output voltage loop, the output current loop and the resonant cavity current loop. The output voltage and output current are the outer loops, which affect each other through the control signal; the resonant cavity current loop is the inner loop, which is responsible for keeping the current of the resonant cavity stable.

[0070] The output voltage loop adjusts the control signal according to the difference (voltage error) between Udc_ref (reference output voltage) and Udc (actual output voltage). The output current loop controls the output current by adjusting the output voltage or other parameters to ensure that Idc (actual output current) is as close as possible to Idc_ref (reference output current).

[0071] The resonant cavity current loop works as an inner feedback control loop, Ir_ref is the input of the inner loop (target current), and Ir is the output of the inner loop (actual current). The main function of the inner control loop is to quickly respond to instantaneous current changes and achieve the actual current Ir close to the reference value Ir_ref by adjusting the switching state of the converter (such as duty cycle or frequency).

[0072] In an exemplary embodiment, see Figure 3 , Figure 3 1 is a circuit connection diagram of an AC-DC module in an embodiment of the present application. The AC-DC module includes a rectifier, and the rectifier includes a first bridge arm, a second bridge arm, and a third bridge arm, and the first bridge arm, the second bridge arm, and the third bridge arm have the same structure. The first bridge arm includes a first switch, a fifth diode D5, and a sixth diode D6, and the cathode of the fifth diode D5 and the anode of the sixth diode D6 are both connected to the DC-DC module, and the first end of the first switch is connected to one phase of the three-phase power supply.

[0073] During operation, the three-phase voltage of the AC grid is connected to the first, second and third bridge arms of the rectifier respectively. The switch of the first bridge arm is connected to a phase voltage in the grid. When the grid voltage reaches a certain threshold, the first switch is turned on, and the current flows through the bridge arm to provide a DC voltage. At the same time, the role of the diode is to ensure the unidirectional flow of current to prevent reverse current from damaging the system. When the grid voltage changes, the switches and diodes in the second and third bridge arms work successively to ensure that the current is stable and continuously flows to the DC-DC module, and finally outputs stable DC power.

[0074] Continue reading Figure 3 The first switch includes a first rectifier switch tube Q3, a first switch diode D7, a second switch diode D8, a third switch diode D9 and a fourth switch diode D11. The cathode of the first switch diode D7 and the cathode of the third switch diode D9 are both connected to the source of the first rectifier switch tube Q3, the anode of the second switch diode D8 and the anode of the fourth switch diode D11 are both connected to the drain of the first rectifier switch tube Q3, the anode of the first switch diode D7 is connected to the cathode of the second switch diode D8, and the anode of the third switch diode D9 is connected to the cathode of the fourth switch diode D11.

[0075] Taking the first bridge arm as an example, the first switch (including the first rectifier switch tube Q3 and four switch diodes) is electrically connected to one phase of the power grid, and automatically controls the conduction and shutdown of the current according to the change of the current phase.

[0076] In the positive half cycle of the AC power grid, the first rectifier switch tube Q3 is turned on, and the current flows to the fifth diode D5 and the sixth diode D6 of the DC module through the first switch diode D7 and the third switch diode D9, completing partial rectification. The switches and diodes in the second and third bridge arms use similar control processes to ensure that the current flow direction can be converted in different phases and convert AC power into stable DC power.

[0077] In an exemplary embodiment, continue to refer to Figure 3 The AC-to-DC module further includes three first filter components, each of which has the same structure, and the first bridge arm, the second bridge arm and the third bridge arm are respectively connected to a first filter component.

[0078] Each first filter component includes a first filter inductor L1, a second filter inductor L2 and a first filter capacitor C31. The first end of the first filter inductor L1 is connected to one phase of a three-phase power supply. The second end of the first filter inductor L1 is respectively connected to the first end of the second filter inductor L2 and the first end of the first filter capacitor C31. The second end of the second filter inductor L2 in each first filter component is connected to the first end of the first switch in each bridge arm, and the second ends of the first filter capacitor C31 in each first filter component are connected to each other.

[0079] The input current first passes through the first filter inductor L1, and the low-frequency component can pass smoothly, while the high-frequency noise and harmonics are suppressed. Then, the current passes through the second filter inductor L2, further weakening the high-frequency component. The second filter capacitor C32 is connected in parallel with the second filter inductor L2 to play the role of energy storage and filtering, eliminating the remaining high-frequency noise in the current and making the output current stable.

[0080] Continue reading Figure 3 The AC-to-DC module also includes a second filter component, which includes a second filter capacitor C32 and a third filter capacitor C33. The first bridge arm, the second bridge arm, and the third bridge arm are all connected to the first end of the second filter capacitor C32, the second end of the second filter capacitor C32 is connected to the first end of the third filter capacitor C33, and the first bridge arm, the second bridge arm, and the third bridge arm are also connected to the second end of the third filter capacitor C33.

[0081] The first end of the first bridge arm, the second bridge arm and the third bridge arm are all connected to the first end of the second filter capacitor C32 to form a connection grid, and current is introduced into the capacitor. At this time, the second filter capacitor C32 acts to store and filter out high-frequency noise and pulsation components in the current, and smoothes the current waveform. The second end of the second filter capacitor C32 is connected to the first end of the 3rd filter capacitor C33 to further strengthen the filtering effect. The second end of the 3rd filter capacitor C33 is connected to the first bridge arm, the second bridge arm and the 3rd bridge arm to ensure that when the current flows to the final output end, the remaining high-frequency components can be further eliminated through the smoothing effect of the 3rd filter capacitor C33, and the current is further stabilized.

[0082] In an exemplary embodiment, continue to refer to Figure 3 The present application provides an AC-to-DC module, which includes a first filter component, a rectifier and a second filter component. The three first filter components are respectively connected to one phase of a three-phase power supply, and the three first filter components are all connected to the rectifier, and the rectifier is also connected to the second filter component, and the second filter component is connected to the DC-to-DC module.

[0083] Each first filter component includes a first filter inductor L1, a second filter inductor L2 and a first filter capacitor C31. The first end of the first filter inductor L1 is connected to one phase of a three-phase power supply. The second end of the first filter inductor L1 is respectively connected to the first end of the second filter inductor L2 and the first end of the first filter capacitor C31. The second end of the second filter inductor L2 in each first filter component is connected to the first end of the first switch in each bridge arm, and the second ends of the first filter capacitor C31 in each first filter component are connected to each other.

[0084] The rectifier includes a first bridge arm, a second bridge arm and a third bridge arm, and the first bridge arm, the second bridge arm and the third bridge arm have the same structure. The first bridge arm includes a first switch, a fifth diode D5 and a sixth diode D6, the cathode of the fifth diode D5 and the anode of the sixth diode D6 are both connected to the DC to DC module, and the first end of the first switch is connected to one phase of the three-phase power supply. The first switch includes a first rectifier switch tube Q3, a first switch diode D7, a second switch diode D8, a third switch diode D9 and a fourth switch diode D11, the cathode of the first switch diode D7 and the cathode of the third switch diode D9 are both connected to the source of the first rectifier switch tube Q3, the anode of the second switch diode D8 and the anode of the fourth switch diode D11 are both connected to the drain of the first rectifier switch tube Q3, the anode of the first switch diode D7 is connected to the cathode of the second switch diode D8, and the anode of the third switch diode D9 is connected to the cathode of the fourth switch diode D11.

[0085] The second filtering component includes a second filter capacitor C32 and a third filter capacitor C33, the first bridge arm, the second bridge arm and the third bridge arm are all connected to the first end of the second filter capacitor C32, the second end of the second filter capacitor C32 is connected to the first end of the third filter capacitor C33, and the first bridge arm, the second bridge arm and the third bridge arm are also connected to the second end of the third filter capacitor C33.

[0086] The three first filter components are connected to each phase of the three-phase power supply to form a preliminary current filter. Each first filter component consists of a first filter inductor L1, a second filter inductor L2 and a first filter capacitor C31 to ensure the smoothness and stability of the current. The rectifier converts AC power into DC power through three bridge arms. The switches and diodes in the bridge arms work together to control the flow direction and rectification process of the current. The output of the rectifier is connected to the second filter component to further smooth the DC voltage and reduce fluctuations.

[0087] In an exemplary embodiment, see Figure 4 , Figure 4 The control principle diagram of the rectifier in one embodiment of the present application is shown. The software phase-locked loop (PLL) samples the input three-phase voltage, converts it into a two-phase stationary coordinate system using Clark transformation, and then obtains the d-axis and q-axis voltage components in the rotating coordinate system through Park transformation.

[0088] The voltage loop regulates the input current by controlling the bus voltage (BUS voltage). When the grid or load changes, the voltage loop uses a PI controller to adjust the current command according to the voltage change to ensure voltage stability. When the load increases, the current loop needs to provide more current to maintain voltage balance.

[0089] The current loop optimizes the power factor and ensures that the current waveform is close to an ideal sine wave by controlling the d-axis and q-axis current components (Id and Iq). Specifically, the Iq component is controlled to zero to achieve the same phase of current and voltage, reduce harmonic distortion, and optimize the power factor. At the same time, the d-axis current (Id) is adjusted to meet the power demand to ensure stable operation of the system.

[0090] SVPWM (Space Voltage Vector Pulse Width Modulation) maximizes the utilization efficiency of the DC side voltage and improves the overall performance and energy efficiency of the inverter by modulating the spatial distribution of the voltage vector.

[0091] In an exemplary embodiment, Figure 5 As shown, the present application provides an output power disturbance method. In this embodiment, the method includes the following steps:

[0092] Step 502 : after adjusting the duty cycle based on the first disturbance scheme, obtaining the current output voltage and the current output current, and determining the current output power based on the current output voltage and the current output current.

[0093] Among them, the first disturbance scheme is a scheme of increasing the duty cycle.

[0094] Exemplarily, the duty cycle is adjusted by a first interference scheme so that the duty cycle increases by a preset value, and then the output voltage and output current that change with the duty cycle are collected to calculate a new output power.

[0095] Step 504: compare the current output power with the previous output power to obtain a first power comparison result.

[0096] Exemplarily, the new output power is compared with the output power of the previous cycle.

[0097] If the new output power is greater than the output power, it means that the current disturbance direction is correct, and the duty cycle can be continued to increase and the disturbance can continue in the same direction.

[0098] If the new output power is less than the output power, it means that the current disturbance direction is wrong, and the system should adjust the duty cycle in the opposite direction to reduce the duty cycle.

[0099] Step 506: When the first power comparison result is that the current output power is equal to the previous output power, the disturbance operation is terminated.

[0100] For example, if the new output power is equal to the output power, it means that increasing the preset value of the duty cycle in the current disturbance operation cannot increase the power. The current disturbance can be ended, and the preset value can be adjusted to perform another disturbance.

[0101] The above output power perturbation method adopts the power perturbation observation method, see Figure 6 , Figure 6 A control schematic diagram of the power disturbance observation method in one embodiment of the present application is shown.

[0102] In an exemplary embodiment, after comparing the current output power with the previous output power to obtain a first power comparison result, the method further includes:

[0103] When the first power comparison result is that the current output power is less than the previous output power, the duty cycle is adjusted based on the second disturbance scheme, and the next output power is obtained; the next output power is compared with the current output power to obtain the second power comparison result; when the second power comparison result is that the next output power is less than the current output power, the disturbance operation is continued until the next output power is equal to the current output power.

[0104] Exemplarily, the duty cycle is repeatedly adjusted according to the change in power, and each time it is determined whether to continue to perturb in the same direction or to perturb in the opposite direction according to whether the power increases, until the maximum power point (MPP) of the photovoltaic panel is reached or approached.

[0105] See also Figure 7 As shown, Figure 7 FIG. 1 is a schematic diagram of a PV simulation curve in an embodiment of the present application. Through the IV curve diagram, that is, Figure 7 In the straight lines 1-2, 2-3, 3-4 and 4-5, the PV curve has a physical relationship with the IV curve.

[0106] Each straight line segment connects two adjacent points, and the slope and intercept of the straight line are determined by linear interpolation based on the relationship between current and voltage. This approximate method not only greatly reduces the computational complexity, but also can better simulate the IV characteristics of photovoltaic cells, and is suitable for use in environments with limited computing power such as DSP. Through this simplified model, an IV curve that meets the requirements can be effectively generated.

[0107] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0108] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A three-phase rectifier, characterized in that: include: An AC-to-DC module, wherein a first end of the AC-to-DC module is connected to a three-phase power supply and is used to convert the AC power output by the three-phase power supply into a constant DC power; A DC-to-DC module, which is connected to the AC-to-DC module and is used for converting the converted constant DC power into a voltage and outputting it. The DC-to-DC module includes an inverter component, a first end of which is connected to the second end of the AC-to-DC converter, and the inverter component includes an inverter bridge arm, which includes an upper bridge arm and a lower bridge arm. The upper bridge arm includes a first inverter switch tube and a second inverter switch tube, and the lower bridge arm includes a third inverter switch tube and a fourth inverter switch tube. The drain of the first inverter switch tube and the source of the fourth inverter switch tube are both connected to the second end of the AC-to-DC module, the source of the first inverter switch tube is connected to the drain of the second inverter switch tube, the source of the second inverter switch tube is connected to the drain of the third inverter switch tube, and the source of the third inverter switch tube is connected to the drain of the fourth inverter switch tube.

2. The three-phase rectifier according to claim 1, characterized in that: The DC-to-DC module also includes a capacitor voltage-dividing component, which is respectively connected to the AC-to-DC module and the inverter component. The capacitor voltage-dividing component includes a first voltage-dividing capacitor and a second voltage-dividing capacitor. The first end of the first voltage-dividing capacitor is connected to the drain of the first inverter switch tube, the second end of the first voltage-dividing capacitor is connected to the first end of the second voltage-dividing capacitor, and the second end of the second voltage-dividing capacitor is connected to the source of the fourth inverter switch tube.

3. The three-phase rectifier according to claim 2, characterized in that: The DC-DC module further includes a resonant network, a first port of the resonant network is connected to the midpoint of the inverter bridge arm, and a second port of the resonant network is connected to the midpoint of the capacitive voltage divider component; The resonant network includes a resonant capacitor and a resonant inductor, and the second end of the resonant inductor is connected to the first end of the resonant capacitor; wherein the first end of the resonant inductor is the first port of the resonant network.

4. The three-phase rectifier according to claim 3, characterized in that: The DC-to-DC module also includes a transformer, a first end of the positive coil of the transformer is connected to the third port of the resonant network, and a second end of the positive coil of the transformer is connected to the fourth port of the resonant network; wherein the second end of the resonant capacitor is the third port of the resonant network, and the third port is connected to the fourth port via a wire.

5. The three-phase rectifier according to claim 4, characterized in that: The DC-to-DC module also includes a secondary rectifier component, which includes a first diode, a second diode, a third diode and a fourth diode. The first end of the secondary coil in the transformer is respectively connected to the anode of the first diode and the cathode of the third diode, the second end of the secondary coil in the transformer is respectively connected to the anode of the second diode and the cathode of the fourth diode, the cathode of the first diode and the cathode of the second diode are connected and serve as a first output end, and the anode of the third diode and the anode of the fourth diode are connected and serve as a second output end.

6. The three-phase rectifier according to claim 1, characterized in that: The AC-DC module includes a rectifier, the rectifier includes a first bridge arm, a second bridge arm and a third bridge arm, and the first bridge arm, the second bridge arm and the third bridge arm have the same structure; The first bridge arm includes a first switch, a fifth diode and a sixth diode, the cathode of the fifth diode and the anode of the sixth diode are both connected to the DC-DC module, and the first end of the first switch is connected to one phase of the three-phase power supply.

7. The three-phase rectifier according to claim 6, characterized in that: The first switch includes a first rectifier switch tube, a first switch diode, a second switch diode, a third switch diode and a fourth switch diode, wherein the cathode of the first switch diode and the cathode of the third switch diode are both connected to the source of the first rectifier switch tube, the anode of the second switch diode and the anode of the fourth switch diode are both connected to the drain of the first rectifier switch tube, the anode of the first switch diode is connected to the cathode of the second switch diode, and the anode of the third switch diode is connected to the cathode of the fourth switch diode.

8. The three-phase rectifier according to claim 6, characterized in that: The AC-DC module further includes three first filter components, each of which has the same structure, and the first bridge arm, the second bridge arm and the third bridge arm are respectively connected to one of the first filter components; Each of the first filter components includes a first filter inductor, a second filter inductor and a first filter capacitor. The first end of the first filter inductor is connected to one phase of the three-phase power supply, the second end of the first filter inductor is respectively connected to the first end of the second filter inductor and the first end of the first filter capacitor, the second end of the second filter inductor in each of the first filter components is connected to the first end of the first switch in each bridge arm, and the second ends of the first filter capacitors in each of the first filter components are connected to each other.

9. An output power disturbance method, applicable to the three-phase rectifier as claimed in any one of claims 1 to 8, characterized in that: The method comprises: After adjusting the duty cycle based on the first disturbance scheme, obtaining a current output voltage and a current output current, and determining a current output power based on the current output voltage and the current output current; Comparing the current output power with the previous output power to obtain a first power comparison result; When the first power comparison result is that the current output power is equal to the previous output power, the disturbance operation is terminated.

10. The output power disturbance method according to claim 9, characterized in that: After comparing the current output power with the previous output power to obtain a first power comparison result, the method further includes: When the first power comparison result is that the current output power is less than the previous output power, adjusting the duty cycle based on the second disturbance scheme and obtaining the next output power; Comparing the next output power with the current output power to obtain a second power comparison result; When the second power comparison result is that the next output power is less than the current output power, the disturbance operation is continued until the next output power is equal to the current output power.

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