Single-phase AC / AC converter

Abstract

The invention discloses a single-phase AC / AC converter which is used for realizing fine adjustment of output signals of a conversion circuit and improving the precision and stability of output AC signals. The circuit comprises a main control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit. Collecting circuit data of an input alternating current signal through a first sampling module and a second sampling module, and inputting the circuit data into a main control chip; the main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data; based on the optimized circuit data, the main control chip outputs a PWM signal to the driving chip; and according to the PWM signal, the driving chip controls a conversion circuit to adjust the alternating current signal to obtain a final output alternating current signal.

Description

Technical Field

[0001] The present application relates to the field of converters, and in particular to a single-phase AC / AC converter. Background Art

[0002] At present, the methods of achieving AC / AC voltage conversion are mainly divided into direct conversion and indirect conversion. Direct conversion is to directly connect the input AC power with the output through a switching device, and obtain the output AC power of the required frequency or different frequencies through the on-off control of the switching device. Indirect conversion is to achieve AC / AC conversion through an intermediate link. Specifically, it is to convert the input AC power into DC power, and then convert the DC power into AC power of the required frequency and amplitude.

[0003] First, from the perspective of stability, the AC / AC voltage converter needs to be able to maintain a constant output voltage under various load conditions. However, in practical applications, load changes are often very frequent, such as the start and stop of motors, the switching of lighting equipment, etc. These changes will cause fluctuations in grid voltage. The design of existing AC / AC voltage converters is not optimized enough, or the control strategy is not flexible enough, which makes it difficult for AC / AC voltage converters to maintain a stable output voltage under load changes.

[0004] Secondly, from the perspective of accuracy, AC / AC voltage converters need to be able to provide high-precision output voltages to meet the needs of various sensitive loads. However, due to the presence of various nonlinear elements and interference factors inside or outside the converter, such as switching losses of switching devices, parasitic parameters of filter circuits, control algorithms, and sampling accuracy, these will affect the accuracy of the output voltage. If the control algorithm is not accurate enough or the sampling accuracy is not high enough, the error of the output voltage will increase, thereby affecting the performance of various loads connected to the output end of the converter.

[0005] These problems not only affect the overall performance of the converter, but also limit its widespread promotion and use in various applications. Summary of the invention

[0006] In order to solve the above technical problems, the present application provides a single-phase AC / AC converter.

[0007] The technical solution provided in this application is described below:

[0008] The present application provides a single-phase AC / AC converter, comprising:

[0009] A main control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit;

[0010] Collecting circuit data of the input AC signal through the first sampling module and the second sampling module, and inputting the circuit data into the main control chip;

[0011] The main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data;

[0012] Based on the optimized circuit data, the main control chip outputs a PWM signal to the driver chip;

[0013] According to the PWM signal, the driver chip controls the conversion circuit to adjust the AC signal to obtain a final output AC signal.

[0014] Optionally, the main control chip includes a first main control chip and a second main control chip, and the circuit data includes current data and voltage data;

[0015] The collecting of circuit data of the input AC signal by the first sampling module and the second sampling module, and inputting the circuit data into the main control chip, comprises:

[0016] The first sampling module collects current data of the input AC signal, and inputs the current data into the first main control chip;

[0017] The voltage data of the input AC signal is collected through the second sampling module, and the voltage data is input into the second main control chip.

[0018] Optionally, the internal preset algorithm is a VMD algorithm;

[0019] The main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data, including:

[0020] The first main control chip analyzes and optimizes the current data by using a VMD algorithm to obtain optimized current data;

[0021] The second main control chip analyzes and optimizes the voltage data through a VMD algorithm to obtain optimized voltage data.

[0022] Optionally, the PWM signal includes a second PWM signal of the first PWM signal, and the drive circuit includes a first drive circuit and a second drive circuit;

[0023] Based on the optimized circuit data, the main control chip outputs a corresponding PWM signal to the driver chip, including:

[0024] Based on the optimized current data, the first main control chip outputs a first PWM signal to the first driver chip;

[0025] Based on the optimized voltage data, the second main control chip outputs a second PWM signal to the second driving chip.

[0026] Optionally, the conversion circuit includes a first conversion circuit and a second conversion circuit;

[0027] According to the PWM signal, the driver chip controls the conversion circuit to adjust the AC signal to obtain a final output AC signal, including:

[0028] According to the first PWM signal, the first driver chip controls the first conversion circuit to adjust the current parameter of the AC signal;

[0029] According to the second PWM signal, the second driving chip controls the second conversion circuit to adjust the voltage parameter of the AC signal;

[0030] A final output AC signal is obtained, and the output AC signal is output to a load.

[0031] Optionally, the conversion circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor and a first inductor;

[0032] The drain of the first switch tube is connected to one end of the second capacitor, and the gate of the first switch tube is connected to one end of the first resistor and one end of the third resistor;

[0033] The source of the first switch tube is connected to the source of the second switch tube, and a first intersection is set at the connection;

[0034] The other end of the third resistor is connected to one end of the fourth resistor, and a second intersection is set at the connection;

[0035] The first intersection and the second intersection are connected and connected to a power source;

[0036] The gate of the second switch tube, the other end of the fourth resistor and one end of the second resistor are connected, and the drain of the second switch tube, one end of the first inductor and the drain of the third switch tube are connected;

[0037] The other end of the first resistor and the other end of the second resistor are connected to the driving chip;

[0038] The gate of the third switch tube is connected to one end of the fifth resistor and one end of the seventh resistor;

[0039] The source of the third switch tube is connected to the source of the fourth switch tube, and a third intersection is set at the connection;

[0040] The other end of the seventh resistor is connected to one end of the eighth resistor, and a fourth intersection is set at the connection;

[0041] The third intersection point is connected to the fourth intersection point and is also connected to a power source;

[0042] The gate of the fourth switch tube, the other end of the eighth resistor and one end of the sixth resistor are connected, and the drain of the fourth switch tube is connected to the other end of the second capacitor and one end of the first capacitor;

[0043] The other end of the first inductor is connected to one end of the first capacitor, and the other end of the fifth resistor and the other end of the sixth resistor are connected to the driver chip;

[0044] Both ends of the second capacitor are connected to the AC signal input end at the same time, and both ends of the first capacitor are connected to the load at the same time.

[0045] Optionally, the main control chip is an STM32F334C8T6 single-chip microcomputer, and the driver chip is UCC21520.

[0046] Optionally, the single-phase AC / AC converter further includes a key circuit, and the key circuit is used to set a step operation on the output AC signal.

[0047] Optionally, the single-phase AC / AC converter further includes a rectifier circuit, and the rectifier circuit is used to reduce the harmonic components of the input AC signal.

[0048] It can be seen from the above technical solutions that this application has the following advantages:

[0049] The first sampling module and the second sampling module can accurately collect circuit data of the input AC signal, including key parameters such as voltage and current, thereby improving the data reliability and measurement accuracy of the entire circuit.

[0050] The main control chip has powerful data processing capabilities and can quickly analyze and optimize the collected circuit data. The optimization algorithm can filter out noise and correct errors to adapt to the changes of different input signals, thereby maintaining the stability of the circuit output. The optimization algorithm used can also reduce circuit instability caused by signal fluctuations or interference, ensuring the stable output of the output AC signal.

[0051] The main control chip can accurately calculate the required PWM signal parameters. By accurately controlling the duty cycle and frequency of the PWM signal, it can achieve fine adjustment of the output signal of the conversion circuit, which can further improve the accuracy and stability of the output AC signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solution in the present application, the drawings required for use in the description of the embodiments 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 any creative work.

[0053] Figure 1 This is an example diagram of an embodiment of a single-phase AC / AC converter of the present application;

[0054] Figure 2 An example diagram of an embodiment of a method for collecting circuit data in the present application;

[0055] Figure 3 An example diagram of an embodiment of a method for optimizing circuit data for the present application;

[0056] Figure 4 An example diagram of an embodiment of a method for outputting a PWM signal according to the present application;

[0057] Figure 5 An exemplary diagram of an embodiment of the method for adjusting an AC signal of the present application;

[0058] Figure 6 This is a circuit diagram of a conversion circuit in a single-phase AC / AC converter of the present application. DETAILED DESCRIPTION

[0059] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0060] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0061] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0062] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0063] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0064] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0065] Based on this, the present application discloses a single-phase AC / AC converter for realizing fine adjustment of the output signal of the conversion circuit and improving the accuracy and stability of the output AC signal.

[0066] 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 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.

[0067] See also Figure 1 The present application first provides an embodiment of a single-phase AC / AC converter, which comprises:

[0068] S101, collecting circuit data of an input AC signal through a first sampling module and a second sampling module, and inputting the circuit data into a main control chip;

[0069] First, the circuit data of the input AC signal is captured and recorded through the first sampling module and the second sampling module. These circuit data may include but are not limited to voltage value, current value, phase information, etc. These circuit data describe the complete state of the AC signal at a certain moment.

[0070] The process of collecting circuit data usually involves periodic measurement of the AC signal to obtain enough data points to accurately reflect the changing pattern of the signal.

[0071] After the complete circuit data is collected, the circuit data is transmitted to the main control chip. The main control chip is responsible for processing and analyzing the circuit data to determine the subsequent operation.

[0072] S102, the main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data;

[0073] After receiving the circuit data, the main control chip will use the internal preset algorithm to conduct in-depth analysis and processing on the data. The algorithm may be a complex mathematical model or empirical formula.

[0074] The analysis process includes but is not limited to signal filtering, spectrum analysis, waveform recognition and other operations. The algorithm optimizes the circuit data by detecting and analyzing the voltage fluctuation and flicker signal of the circuit data. The optimized circuit data can better maintain the output current and voltage and achieve more accurate control.

[0075] S103, based on the optimized circuit data, the main control chip outputs a PWM signal to the driver chip;

[0076] After obtaining the optimized circuit data, the main control chip generates a series of pulse width modulation (PWM) signals and sends these PWM signals to the driver chip. PWM signals can adjust the power or level of the output signal by changing the width of the pulse (i.e., the duty cycle). The generation of PWM signals is based on the optimized circuit data to ensure that the width of each pulse can accurately reflect the required adjustment amount.

[0077] The driver chip is a bridge connecting the main control chip and the conversion circuit. After receiving the PWM signal, the driver chip converts it into a signal that can drive the conversion circuit.

[0078] S104 , according to the PWM signal, the driver chip controls the conversion circuit to adjust the AC signal to obtain a final output AC signal.

[0079] Finally, the driver chip controls the switching elements in the conversion circuit to switch in a specific manner according to the received PWM signal, thereby adjusting the waveform, amplitude, frequency and other characteristics of the input AC signal.

[0080] After adjustment by the conversion circuit, the original input AC signal is converted into a final output AC signal that meets specific requirements.

[0081] In this embodiment, the first sampling module and the second sampling module can accurately collect circuit data of the input AC signal, including key parameters such as voltage and current, thereby improving the data reliability and measurement accuracy of the entire circuit.

[0082] The main control chip has powerful data processing capabilities and can quickly analyze and optimize the collected circuit data. The optimization algorithm can filter out noise and correct errors to adapt to the changes of different input signals, thereby maintaining the stability of the circuit output. The optimization algorithm used can also reduce circuit instability caused by signal fluctuations or interference, ensuring the stable output of the output AC signal.

[0083] The main control chip can accurately calculate the required PWM signal parameters. By accurately controlling the duty cycle and frequency of the PWM signal, it can achieve fine adjustment of the output signal of the conversion circuit, which can further improve the accuracy and stability of the output AC signal.

[0084] See also Figure 2 In a specific embodiment, the main control chip includes a first main control chip and a second main control chip, and the circuit data includes current data and voltage data. The present application provides an embodiment of a method for collecting circuit data, including:

[0085] S201, collecting current data of an input AC signal through a first sampling module, and inputting the current data into a first main control chip;

[0086] The first sampling module is a current sensor, which can convert the received AC current into a measurable voltage signal or digital signal. The current sensor usually has the characteristics of high sensitivity, high precision and fast response to ensure that the collected current data is accurate.

[0087] After the current data is collected, the current data is transmitted to the first main control chip. The data transmission can be carried out in the form of analog signals or digital signals, depending on the interface design between the sampling module and the main control chip. If digital signal transmission is adopted, an analog-to-digital converter (ADC) may also be required to assist the main control chip in receiving the current data.

[0088] S202 , collecting voltage data of the input AC signal through a second sampling module, and inputting the voltage data into a second main control chip.

[0089] The second sampling module uses a current-type voltage transformer to measure the AC voltage, and can accurately convert the received AC voltage into a measurable current signal or digital signal. The current-type voltage transformer usually has the characteristics of high stability, high precision and strong anti-interference ability.

[0090] After the voltage data is collected, it is transmitted to the second main control chip. The data transmission can be carried out in the form of analog signals or digital signals, depending on the interface design between the sampling module and the main control chip. If digital signal transmission is adopted, the analog-to-digital conversion (ADC) process may also be required. If digital signal transmission is adopted, the analog-to-digital conversion (ADC) process may also be required to assist the main control chip in receiving current data.

[0091] In this embodiment, the first sampling module can capture the current data of the AC signal in real time to monitor the circuit load, current fluctuations, and potential short circuit or overload phenomena; the second sampling module can obtain the voltage data of the AC signal in real time to ensure the stable operation of the circuit. The current data and voltage data are input into the main control chip to achieve comprehensive monitoring and management of the circuit status.

[0092] See also Figure 3 In a specific embodiment, the internal preset algorithm is a VMD algorithm. The present application provides an embodiment of a method for optimizing circuit data, including:

[0093] S301, the first main control chip analyzes and optimizes the current data by using a VMD algorithm to obtain optimized current data;

[0094] The first main control chip performs in-depth analysis and optimization on the previously collected current data by applying the variational mode decomposition (VMD) algorithm.

[0095] The VMD algorithm is an adaptive, completely non-recursive modal variation and signal processing method. The algorithm has the advantage of being able to determine the number of modal decompositions. Its adaptability is reflected in determining the number of modal decompositions of a given sequence according to actual conditions. In the subsequent search and solution process, it can adaptively match the optimal center frequency and limited bandwidth of each mode, and can achieve effective separation of intrinsic modal components (IMFs), frequency domain division of signals, and then obtain effective decomposition components of a given signal, and finally obtain the optimal solution to the variational problem. The VMD algorithm has a solid mathematical theoretical foundation, which can reduce the non-stationarity of time series with high complexity and strong nonlinearity, decompose and obtain relatively stable subsequences containing multiple different frequency scales, and is suitable for non-stationary sequences. The core idea of ​​the VMD algorithm is to construct and solve variational problems.

[0096] The first master control chip first receives the current data from the first sampling module. These current data may contain noise, harmonics or other non-ideal components, which need to be analyzed and purified. The first master control chip will apply the VMD algorithm to perform a series of complex calculations, including constructing and solving variational problems to minimize the bandwidth of each IMF and ensure that their sum is as close to the original signal as possible. Through the application of the VMD algorithm, the first master control chip can identify and separate the useful components in the current data while removing or reducing noise and interference.

[0097] Finally, the first main control chip outputs optimized current data, which is more accurate and clear and reflects the true characteristics of the original current signal.

[0098] S302 . The second main control chip analyzes and optimizes the voltage data by using a VMD algorithm to obtain optimized voltage data.

[0099] This step uses a similar method to S301, but this time it targets voltage data and is implemented through a second master chip and a VMD algorithm.

[0100] The second main control chip receives voltage data from the second sampling module, which may also contain undesirable components such as noise and harmonics. The second main control chip uses the VMD algorithm to detect and analyze voltage fluctuations and flicker signals on the voltage data. By decomposing the voltage signal through the VMD algorithm, each modal component can be accurately extracted, and then the amplitude, frequency, content and frequency distribution of harmonic components of the voltage fluctuation can be analyzed. This includes constructing variational problems, solving IMFs, and ensuring that the sum of IMFs is as close as possible to the original voltage signal. Through the application of the VMD algorithm, the second main control chip can identify and separate useful components in the voltage data while removing or reducing noise and interference.

[0101] Finally, the second main control chip outputs optimized voltage data, which is more accurate and clear and reflects the true characteristics of the original voltage signal.

[0102] In this embodiment, the VMD algorithm is applied to optimize the current and voltage data, thereby improving the accuracy and reliability of the circuit data, optimizing the current and voltage waveforms, and thus improving the performance and stability of the entire system. At the same time, the application of the VMD algorithm also helps to reduce energy consumption, protect sensitive components and devices in the circuit, and enhance the robustness and reliability of the system.

[0103] See also Figure 4 In a specific embodiment, the PWM signal includes a second PWM signal of the first PWM signal, the driving circuit includes a first driving circuit and a second driving circuit, and the present application provides an embodiment of a method for outputting a PWM signal, including:

[0104] S401, based on the optimized current data, the first main control chip outputs a first PWM signal to the first driver chip;

[0105] According to the current data optimized by the VMD algorithm, a specific pulse width modulation (PWM) signal, namely the first PWM signal, is generated and outputted by the first main control chip. The optimized current data provides key information about the current waveform, amplitude, phase, etc., which is the basis for generating the PWM signal.

[0106] The first main control chip calculates the required duty cycle, frequency and other parameters of the PWM signal based on the key information. The duty cycle refers to the proportion of the high level (or effective level) in the PWM signal, indicating the average value of the output current. The frequency indicates the periodic change speed of the PWM signal.

[0107] The generation of PWM signals involves complex algorithms and calculations to ensure that the output current can accurately track the optimized current data. The algorithm can use digital signal processing (DSP) technology, table lookup, real-time calculation and other methods.

[0108] The generated first PWM signal is then sent to the first driving chip.

[0109] S402: Based on the optimized voltage data, the second main control chip outputs a second PWM signal to the second driving chip.

[0110] This step is similar to S401, but this time it is for voltage data. According to the optimized voltage data, a specific second PWM signal is generated by the second main control chip.

[0111] The optimized voltage data provides key information about the voltage waveform, amplitude, phase, etc. Based on this key information, the second main control chip calculates the required duty cycle, frequency and other parameters of the second PWM signal to ensure that the output voltage can accurately track the optimized voltage data.

[0112] The generated second PWM signal is then sent to the second driving chip.

[0113] In this embodiment, based on the optimized current data and voltage data, the first main control chip and the second main control chip can accurately generate effective PWM signals and send them to the corresponding drive control chip to provide drive signals for subsequent precise control of the current and voltage of the AC signal.

[0114] See also Figure 5 In a specific embodiment, the conversion circuit includes a first conversion circuit and a second conversion circuit. The present application provides an embodiment of a method for regulating an AC signal, including:

[0115] S501: According to a first PWM signal, a first driver chip controls a first conversion circuit to adjust a current parameter of an AC signal;

[0116] The first PWM signal instructs the first conversion circuit to adjust the current by changing the duty cycle. The first driver chip is responsible for converting the first PWM signal into a signal that can directly drive the first conversion circuit.

[0117] The first conversion circuit is usually a complex circuit including inductors, capacitors, MOS tubes and other components, which is used to convert the input AC signal into a signal with the required current parameters. This conversion process may involve current amplification, filtering, phase adjustment and other operations.

[0118] According to the instruction of the first PWM signal, the electronic components in the first conversion circuit will switch according to a specific timing, thereby changing the current path and current size in the circuit, thereby achieving precise adjustment of the current parameters.

[0119] S502: According to the second PWM signal, the second driving chip controls the second conversion circuit to adjust the voltage parameter of the AC signal;

[0120] This step is similar to S501, but this time it is for adjusting the voltage parameters. The second PWM signal also instructs the second conversion circuit to adjust the voltage by changing the duty cycle. The second driver chip is responsible for converting the second PWM signal into a signal that can directly drive the electronic devices in the second conversion circuit.

[0121] The second conversion circuit is similar to the first conversion circuit. According to the instruction of the second PWM signal, the electronic components in the second conversion circuit will switch according to a specific timing, thereby changing the voltage distribution and voltage size in the circuit and realizing accurate adjustment of the voltage parameters.

[0122] S503: Obtain a final output AC signal, and output the output AC signal to a load.

[0123] The AC signals regulated by the first conversion circuit and the second conversion circuit are combined to form a final output AC signal, which has the required current and voltage parameters and is output to the load.

[0124] The output AC signal is a precisely regulated signal that meets the system's requirements for current and voltage parameters. The load is the device or circuit that the system needs to power. The output AC signal is transmitted to the load to provide it with the required electrical energy.

[0125] In this embodiment, according to the first PWM signal, the first driver chip can control the first conversion circuit to accurately adjust the current parameters of the AC signal; similar to the current regulation, according to the second PWM signal, the second driver chip can control the second conversion circuit to accurately adjust the voltage parameters of the AC signal.

[0126] By precisely adjusting the current and voltage parameters, the final optimized output AC signal can be obtained. The optimized AC signal matches the load requirements in terms of current and voltage, thereby improving the overall performance and efficiency of the system. By controlling the conversion circuit with PWM signals, the system can flexibly adjust the current and voltage parameters of the output AC signal to adapt to different load requirements and working environments.

[0127] See also Figure 6 , the present application provides a circuit diagram of a conversion circuit in a single-phase AC / AC converter, comprising:

[0128] The conversion circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor and a first inductor;

[0129] The drain of the first switch tube is connected to one end of the second capacitor, and the gate of the first switch tube is connected to one end of the first resistor and one end of the third resistor;

[0130] The source of the first switch tube is connected to the source of the second switch tube, and a first intersection is set at the connection;

[0131] The other end of the third resistor is connected to one end of the fourth resistor, and a second intersection is set at the connection;

[0132] The first intersection point and the second intersection point are connected and connected to a power source at the same time;

[0133] The gate of the second switch tube, the other end of the fourth resistor and one end of the second resistor are connected, and the drain of the second switch tube, one end of the first inductor and the drain of the third switch tube are connected;

[0134] The other end of the first resistor and the other end of the second resistor are connected to the driving chip;

[0135] The gate of the third switch tube is connected to one end of the fifth resistor and one end of the seventh resistor;

[0136] The source of the third switch tube is connected to the source of the fourth switch tube, and a third intersection is set at the connection;

[0137] The other end of the seventh resistor is connected to one end of the eighth resistor, and a fourth intersection is set at the connection;

[0138] The third intersection point is connected to the fourth intersection point and is also connected to a power source;

[0139] The gate of the fourth switch tube, the other end of the eighth resistor and one end of the sixth resistor are connected, and the drain of the fourth switch tube is connected to the other end of the second capacitor and one end of the first capacitor;

[0140] The other end of the first inductor is connected to one end of the first capacitor, and the other end of the fifth resistor and the other end of the sixth resistor are connected to the driver chip;

[0141] Both ends of the second capacitor are connected to the AC signal input end at the same time, and both ends of the first capacitor are connected to the load at the same time;

[0142] Working principle of conversion circuit:

[0143] The converter first determines the working state of the switch tube according to the polarity of the input voltage, and controls the effective value and frequency of the output voltage by changing the switching time of the switch tube. The four switches cannot be turned on and off at the same time. When they are turned on at the same time, the circuit will generate a surge current and damage the circuit; when they are turned off at the same time, the energy stored in the inductor has no way to be released, which will damage the switch tube.

[0144] When the input voltage polarity is positive, a specific set of switch tubes (such as the first switch tube and the fourth switch tube) will remain in the on state, while another set of switch tubes (such as the second switch tube and the third switch tube) will perform high-frequency PWM (pulse width modulation) modulation. When the input voltage polarity is negative, the working state of the switch tube will be opposite, that is, the switch tube that was originally turned on will be turned off, the switch tube that was originally performing high-frequency PWM modulation will remain in the on state, and the other set of switch tubes will perform high-frequency PWM modulation.

[0145] By adjusting the duty cycle of the input PWM signal, the amplitude of the output voltage can be controlled. The larger the duty cycle, the higher the output voltage; the smaller the duty cycle, the lower the output voltage.

[0146] In a specific embodiment, a key circuit is further included. The key circuit includes one or more keys. The keys are used to perform step operations on the output AC signal.

[0147] In a specific embodiment, a rectifier circuit is further included, and the rectifier circuit is used to reduce the harmonic components of the input AC signal.

[0148] In the above embodiment, the switch tube driver chip can be selected as UCC21520. UCC21520 has a source current of 4A and a sink current of 6A, which significantly accelerates the load rise time and fall time of high-frequency switching power supply applications, such as the rise time of 1.8nF load is 6ns and the fall time is 7ns, thereby reducing switching losses and improving power efficiency. It also provides 5.7kVRMS enhanced isolation, which can effectively isolate high voltage environments and protect equipment from electric shock and electromagnetic interference.

[0149] The main control chip can use STM32F334C8T6 single-chip microcomputer, and feedback control is performed through the single-chip microcomputer. The main control chip samples the effective value of the AC signal and uses the PID algorithm to calculate the PWM wave duty cycle of the AC-AC conversion circuit, thereby accurately controlling the AC signal output through the AC-AC conversion circuit.

[0150] Before the output AC signal is transmitted to the load, the AC signal is subjected to Fourier analysis to convert the time domain signal into a frequency domain signal, obtain its frequency and amplitude, and then compare the amplitude conversion coefficient through multiple data measurements. Discrete Fourier transform (DFT) is a discrete form of Fourier transform in both time and frequency domains, which transforms the sampling of the time domain signal into sampling in the discrete time Fourier transform (DTFT) frequency domain. In form, the sequences at both ends of the transform (in the time domain and frequency domain) are of finite length, but in fact both sets of sequences should be considered as the main value sequences of discrete periodic signals. Even if DFT is performed on a discrete signal of finite length, it should be regarded as a periodic signal after periodic extension before transformation. After using fast Fourier transform to efficiently calculate DFT, the STM32F334C8T6 microcontroller is used for fft analysis.

[0151] FFT analysis uses the FFT algorithm to perform sampling analysis by comparing the frequency and amplitude of the fundamental and harmonic waves of the sampled AC signal. After FFT analysis, each point represents the amplitude of a frequency, and it is easy to obtain the frequency and peak-to-peak value of the fundamental and harmonic waves through analysis. Based on the obtained frequency and peak-to-peak value of the fundamental and harmonic waves, a suitable LC filter can be designed to ensure the stability of the output AC signal waveform.

[0152] Analysis of the stability and accuracy of the AC signal output by the switch: Input the AC signal into the AC-AC circuit, use a multimeter to measure the current and voltage, a microcontroller to measure the frequency and peak value, and an oscilloscope to observe the waveform, output frequency and peak value.

[0153] (1) Voltage output debugging results

[0154] Table 1: Fixed input and load output voltage test results

[0155]

[0156]

[0157] (2) Current ratio debugging results (K = Io1 / Io2)

[0158] Table 2: Fixed current 5A current ratio K test results

[0159]

[0160] (3) Relative error absolute value debugging results

[0161] Table 3: Relative error test results for fixed output current ratio K

[0162]

[0163] The measurement results show that the output voltage is adjustable in steps within the range of 1V to 35V, the actual output is stable and the error is small, the fixed current 5A current ratio K is within the range of 0.9 to 1.1, the absolute value δ of the relative error between the set K and the actual measured K is no more than 3%, the total harmonic distortion (THD) of the output AC voltage is no more than 5%, and the output AC signal has high accuracy.

[0164] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0165] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0166] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0167] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk, etc. Various media that can store program codes.

Claims

1. A single-phase AC / AC converter, characterized in that: include: A main control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit; Collecting circuit data of the input AC signal through the first sampling module and the second sampling module, and inputting the circuit data into the main control chip; The main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data; Based on the optimized circuit data, the main control chip outputs a PWM signal to the driver chip; According to the PWM signal, the driver chip controls the conversion circuit to adjust the AC signal to obtain a final output AC signal.

2. The single-phase AC / AC converter according to claim 1, characterized in that: The main control chip includes a first main control chip and a second main control chip, and the circuit data includes current data and voltage data; The collecting of circuit data of the input AC signal by the first sampling module and the second sampling module, and inputting the circuit data into the main control chip, comprises: The first sampling module collects current data of the input AC signal, and inputs the current data into the first main control chip; The voltage data of the input AC signal is collected through the second sampling module, and the voltage data is input into the second main control chip.

3. The single-phase AC / AC converter according to claim 2, characterized in that: The internal preset algorithm is the VMD algorithm; The main control chip analyzes and optimizes the circuit data through an internal preset algorithm to obtain optimized circuit data, including: The first main control chip analyzes and optimizes the current data by using a VMD algorithm to obtain optimized current data; The second main control chip analyzes and optimizes the voltage data through a VMD algorithm to obtain optimized voltage data.

4. The single-phase AC / AC converter according to claim 3, characterized in that: The PWM signal includes a second PWM signal of the first PWM signal, and the driving circuit includes a first driving circuit and a second driving circuit; Based on the optimized circuit data, the main control chip outputs a corresponding PWM signal to the driver chip, including: Based on the optimized current data, the first main control chip outputs a first PWM signal to the first driver chip; Based on the optimized voltage data, the second main control chip outputs a second PWM signal to the second driving chip.

5. The single-phase AC / AC converter according to claim 4, characterized in that: The conversion circuit includes a first conversion circuit and a second conversion circuit; According to the PWM signal, the driver chip controls the conversion circuit to adjust the AC signal to obtain a final output AC signal, including: According to the first PWM signal, the first driver chip controls the first conversion circuit to adjust the current parameter of the AC signal; According to the second PWM signal, the second driving chip controls the second conversion circuit to adjust the voltage parameter of the AC signal; A final output AC signal is obtained, and the output AC signal is output to a load.

6. The single-phase AC / AC converter according to claim 1, characterized in that: The conversion circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor and a first inductor; The drain of the first switch tube is connected to one end of the second capacitor, and the gate of the first switch tube is connected to one end of the first resistor and one end of the third resistor; The source of the first switch tube is connected to the source of the second switch tube, and a first intersection is set at the connection; The other end of the third resistor is connected to one end of the fourth resistor, and a second intersection is set at the connection; The first intersection and the second intersection are connected and connected to a power source; The gate of the second switch tube, the other end of the fourth resistor and one end of the second resistor are connected, and the drain of the second switch tube, one end of the first inductor and the drain of the third switch tube are connected; The other end of the first resistor and the other end of the second resistor are connected to the driving chip; The gate of the third switch tube is connected to one end of the fifth resistor and one end of the seventh resistor; The source of the third switch tube is connected to the source of the fourth switch tube, and a third intersection is set at the connection; The other end of the seventh resistor is connected to one end of the eighth resistor, and a fourth intersection is set at the connection; The third intersection point is connected to the fourth intersection point and is also connected to a power source; The gate of the fourth switch tube, the other end of the eighth resistor and one end of the sixth resistor are connected, and the drain of the fourth switch tube is connected to the other end of the second capacitor and one end of the first capacitor; The other end of the first inductor is connected to one end of the first capacitor, and the other end of the fifth resistor and the other end of the sixth resistor are connected to the driver chip; Both ends of the second capacitor are connected to the AC signal input end at the same time, and both ends of the first capacitor are connected to the load at the same time.

7. The single-phase AC / AC converter according to any one of claims 1 to 5, characterized in that: The main control chip is a STM32F334C8T6 single-chip microcomputer, and the driver chip is a UCC21520.

8. The single-phase AC / AC converter according to any one of claims 1 to 5, characterized in that: The single-phase AC / AC converter further comprises a key circuit, and the key circuit is used to set a stepping operation on the output AC signal.

9. The single-phase AC / AC converter according to any one of claims 1 to 5, characterized in that: The single-phase AC / AC converter further includes a rectifier circuit, which is used to reduce the harmonic components of the input AC signal.

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