High-performance dynamic voltage restorer optimized rectifier circuit and modulation method

Abstract

The application provides a high-performance dynamic voltage restorer optimization rectifier circuit and a modulation method, comprising an input power supply circuit, a rectifier circuit, a voltage amplitude adjustment circuit and a load; the voltage amplitude adjustment circuit comprises a first power switch and a second power switch, the first power switch and the second power switch are connected in parallel with the output end of the rectifier circuit, the first power switch is connected in parallel with the second power switch, and the load is connected in parallel with the first power switch and the second power switch; the working mode switching of the voltage amplitude adjustment circuit is controlled by the absolute value of the alternating voltage instantaneous value and the size of the direct current output voltage, the conduction and the off state of the first power switch and the second power switch are controlled, and the smooth switching of different operation modes is realized. Through the collaborative optimization of the rectification and the modulation process, the input current is continuously controllable, the average voltage stress borne by the power switch is reduced, and the current distortion and the dead zone problem in the traditional method are inhibited.

Description

Technical Field

[0001] This application relates to the field of power electronic converter technology, specifically to a high-performance dynamic voltage restorer optimized rectifier circuit and modulation method. Background Technology

[0002] In the field of power quality management and voltage disturbance compensation, the Dynamic Voltage Restorer (DVR), as a series-type power quality regulation device, has become an important technical means to mitigate voltage dips, short-term interruptions, and harmonic pollution. To ensure the DVR's rapid response capability and output voltage quality during voltage compensation, the front-end rectifier circuit typically plays a crucial role in stabilizing the AC power supply to the DC bus voltage. Therefore, high-performance rectifier circuits and their modulation methods are of great significance for improving the overall performance of the DVR.

[0003] Traditional rectification schemes often draw on single-phase power factor correction (PFC) technology, employing diode rectification or boost-type active rectifier structures. Boost-type rectifier circuits are widely used due to their continuous input current characteristics, which excel in reducing input current harmonics and improving the power factor. However, this type of structure typically requires boosting the DC bus voltage to a level higher than the peak AC input voltage. This not only increases the voltage stress and switching losses of power devices but also imposes higher insulation and design requirements on the subsequent inverter compensation unit, thereby increasing system costs. Furthermore, a constant high-voltage DC bus reduces the system's flexibility under different compensation depths and load conditions.

[0004] To address the aforementioned issues, employing a buck rectifier structure to provide an adjustable DC bus voltage for the dynamic voltage restorer has emerged as a potential solution. Compared to traditional boost rectifier structures, buck rectifier circuits can achieve flexible adjustment of the DC bus voltage while ensuring lower device voltage stress, making them more suitable for medium- and low-voltage compensation scenarios. However, while simply using a two-stage structure (such as a cascaded boost rectifier stage and buck converter stage) can achieve both high power factor and voltage regulation capability, it introduces problems such as high intermediate bus voltage levels, complex control strategies, increased system losses, and higher costs, which are detrimental to the miniaturization and high-efficiency design of dynamic voltage restorer systems.

[0005] Building upon this foundation, some studies have proposed improved topologies and control methods. For example, cascaded buck-boost high power factor rectifiers employ a staged current control strategy, using average current control and charge control in different operating ranges to improve input current quality. However, their control circuits are complex, and current distortion is prone to occur during mode switching. Similarly, some bridgeless rectifier topologies based on component reuse can reduce voltage stress on switching devices and improve device utilization, but their current path reconstruction is complex, resulting in current dead zones and additional conduction losses. Furthermore, some existing buck-boost control methods are primarily geared towards DC input scenarios and do not consider the nonlinear characteristics near the voltage zero-crossing point under AC input, making them difficult to apply to systems requiring sinusoidal AC input, such as dynamic voltage restorers.

[0006] Therefore, in applications targeting high-performance dynamic voltage restorers, there is an urgent need for an optimized rectifier circuit and its modulation method that combines low voltage stress, high power factor, no input current dead zone, and simple control, in order to improve the dynamic response capability and system operating efficiency of the dynamic voltage restorer during voltage disturbance compensation. Summary of the Invention

[0007] In view of one of the defects in the prior art, the purpose of this application is to provide a high-performance dynamic voltage restorer optimized rectifier circuit and modulation method.

[0008] The first aspect of this application provides a high-performance dynamic voltage restorer optimized rectifier circuit and modulation method, including: Input power circuit, used to provide AC voltage; A rectifier circuit, connected to the output terminal of the power supply circuit, is used to convert the sinusoidal AC voltage into a voltage with the absolute value of a sinusoidal waveform; A voltage amplitude adjustment circuit, connected to the output terminal of the rectifier circuit, is used to switch the operating mode according to the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage to eliminate the input current dead zone and output a stable DC output voltage. A load is connected to the output terminal of the voltage amplitude regulation circuit to receive the DC output voltage; The voltage amplitude adjustment circuit includes a first power switch and a second switch. The first power switch and the second power switch are connected in parallel with the output terminal of the rectifier circuit. The first power switch and the second power switch are connected in parallel, and the load is connected in parallel with the first power switch and the second power switch. The operating mode switching of the voltage amplitude regulation circuit is controlled by the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, thereby controlling the on and off states of the first power switch and the second power switch to achieve smooth switching between different operating modes.

[0009] Optionally, the operating mode includes a combination of Buck mode, Boost mode, and Buck-Boost mode; The combination includes the combination of the Buck mode and the Boost mode; the combination of the Buck mode and the Buck-Boost mode; The voltage amplitude adjustment circuit eliminates the input current dead zone by switching between the Buck mode, the Boost mode, and the Buck-Boost mode through the first power switch and the second power switch connected in parallel, and outputs a stable DC output voltage.

[0010] Optionally, the operating mode switching of the voltage amplitude regulation circuit is controlled by the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, controlling the on and off states of the first power switch and the second power switch, including; When the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage, the on and off states of the first power switch and the second power switch are controlled to make the voltage amplitude adjustment circuit work in Buck mode. When the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage, the on and off states of the first power switch and the second power switch are controlled to make the voltage amplitude adjustment circuit work in Buck-Boost mode or Boost mode.

[0011] Optionally, the voltage amplitude adjustment circuit further includes: diode De, diode Df, filter inductor La, and filter capacitor Cb; When the voltage amplitude adjustment circuit is in the combination switching between Buck mode and Boost mode, the cathode of diode De is connected to one end of the filter inductor La, the anode of diode De is connected to the drain of the first power switch Sa and the negative terminal of the filter capacitor Cb, the other end of the filter inductor La is connected to the drain of the second power switch Sb and the anode of diode Df, the cathode of diode Df is connected to the negative terminal of the filter capacitor, the source of the first power switch Sa is connected to the source of the second power switch Sb and grounded, and the load is connected in parallel with the filter capacitor Cb.

[0012] Optionally, when the voltage amplitude adjustment circuit operates in the Buck mode, the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage, controlling the first power switch Sa to periodically turn on and off, keeping the second power switch Sb always off, and stabilizing the DC output voltage through the filter inductor La and the filter capacitor Cb. When the voltage amplitude adjustment circuit switches to the Boost mode, the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage. The first power switch Sa and the power switch are controlled to periodically and complementaryly turn on and off. The DC output voltage is stabilized by the filter inductor La and the filter capacitor Cb, eliminating the input current dead zone.

[0013] Optionally, when the voltage amplitude adjustment circuit is in the combination switching between Buck mode and Buck-Boost mode, the cathode of diode De is connected to one end of the filter inductor La, the anode of diode De is connected to the negative terminal of the filter capacitor Cb and the anode of diode Df, the other end of the filter inductor La is connected to the positive terminal of the filter capacitor Cb and the drain of the second power switch Sb, the cathode of diode Df is connected to the drain of the first power switch Sa, and the source of the second power switch Sb is connected to the source of the first power switch Sa and grounded.

[0014] Optionally, when the voltage amplitude adjustment circuit operates in the Buck mode, the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage, controlling the first power switch Sa to periodically turn on and off, keeping the second power switch Sb always off, and stabilizing the DC output voltage through the filter inductor La and the filter capacitor Cb. When the voltage amplitude adjustment circuit switches to the Buck-Boost mode, the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage. This controls the second power switch Sb to periodically turn on and off, keeping the first power switch Sa always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb, eliminating the input voltage dead zone.

[0015] Optionally, the rectifier circuit includes diodes Da, Db, Dc, and Dd, and resistor Ra; The cathode of diode Da is connected to the cathode of diode Dc and one end of resistor Ra. The cathode of diode Db is connected to the anode of diode Da. The anode of diode Db is connected to the anode of diode Dd and the other end of resistor Ra, and then grounded. The anode of diode Dc is connected to the cathode of diode Dd. Diode Dc, the cathode of diode Da, and one end of resistor Ra are connected, and then connected to the cathode of diode De and one end of filter inductor La. The other end of resistor Ra is connected to the source of power switch Sb. The diodes Da and Db are connected to the positive terminal of the power supply circuit, and the diodes Dc and Dd are connected to the negative terminal of the input power supply circuit.

[0016] Optionally, the input power supply circuit includes a power supply. ui、 An electrolytic capacitor Ca, wherein the positive terminal of the electrolytic capacitor Ca is connected to the power supply. UI The positive terminal is connected, and the negative terminal of the electrolytic capacitor Ca is connected to the power supply. UI Negative terminal connection; The anode of diode Da and the cathode of diode Db are connected to the positive terminal of electrolytic capacitor Ca, and the cathode of diode Dd and the anode of diode Dc are connected to the negative terminal of electrolytic capacitor Ca.

[0017] A second aspect of this application provides a high-performance dynamic voltage restorer optimized rectifier circuit and modulation method, including: Obtain a stable sinusoidal AC voltage supplied by the input power supply circuit; The sinusoidal AC voltage is input to the rectifier circuit, and the output is the absolute value of the instantaneous AC voltage with a stable sinusoidal absolute value waveform. Based on the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, the operating mode is switched by controlling the first and second power switches in the voltage amplitude adjustment circuit to eliminate the input current dead zone and output a stable DC output voltage.

[0018] This application provides an optimized rectifier circuit and modulation method for a high-performance dynamic voltage restorer. This method constructs an integrated structure of rectification and adaptive buck-boost based on sinusoidal absolute voltage, achieving efficient energy conversion from AC input to a low-voltage DC bus, providing a stable and adjustable DC support voltage for the dynamic voltage restorer compensation unit. Employing a technique that allows the rectifier circuit to output a sinusoidal absolute waveform voltage and a switchable buck current operating mode, the rectifier circuit converts the input sinusoidal AC voltage into a sinusoidal absolute waveform voltage. Then, a voltage amplitude adjustment circuit controls the switching of the parallel first and second power switches based on the absolute value of the instantaneous AC voltage of the sinusoidal absolute waveform and the target DC output voltage, eliminating the input current dead zone and achieving high-voltage AC to low-voltage DC conversion, resulting in a stable low-voltage DC output. Through this collaborative control mechanism, operation without input current dead zone can be achieved across the entire operating range, avoiding device voltage stress and system complexity issues caused by the intermediate high-voltage bus, while simultaneously reducing control implementation difficulty and system cost. Furthermore, by continuously modulating the mode switching process, the current distortion at the switching point in traditional schemes is effectively suppressed, improving input current quality and system power factor. Therefore, the optimized rectifier circuit and modulation method proposed in this application can provide stable low-voltage DC bus voltage support for the dynamic voltage restorer under high-voltage grid input conditions, possessing low voltage stress, high power factor, no current dead zone, and excellent dynamic performance. It is suitable for power quality management scenarios such as voltage sag compensation. It is applicable to load applications with high-voltage input and low-voltage supply, solving the problems of complex control circuits, high cost, and current distortion at the mode switching point in traditional high-voltage differential power electronic converters with higher voltage input and lower voltage output.

[0019] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0020] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the topology of a Buck and Boost mode switching circuit for a high-performance dynamic voltage restorer optimized rectifier circuit and modulation method, according to an exemplary embodiment. Figure 2 The waveform diagram showing the on and off waveforms of power switches Sa and Sb according to an exemplary embodiment is used to realize the switching between Buck and Boost operating modes. Figure 3 This is a schematic diagram of the topology of a Buck and Buck-Boost mode switching circuit for a high-performance dynamic voltage restorer optimized rectifier circuit according to an exemplary embodiment. Figure 4 The waveform diagram showing the on and off waveforms of power switches Sa and Sb according to an exemplary embodiment is used to realize the switching between Buck and Buck-Boost operating modes. Figure 5 This is a flowchart illustrating a modulation method for optimizing a rectifier circuit using a high-performance dynamic voltage restorer, according to an exemplary embodiment. Detailed Implementation

[0021] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0022] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0024] In the description of the embodiments in this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or devices.

[0026] In existing technologies, traditional high-voltage differential power electronic converters with higher input voltage and lower output voltage, such as Buck-type single-phase active PFC or single-phase Buck PFC, suffer from complex control circuits, high costs, current distortion at mode switching points, input current dead zones, and high average voltage stress on the power switches. To address these issues, this application provides a high-performance dynamic voltage restorer with optimized rectifier circuitry and modulation method to solve these problems.

[0027] Reference Figure 1 As shown in one embodiment of this application, a high-performance dynamic voltage restorer optimized rectifier circuit includes: an input power supply circuit, a rectifier circuit, a voltage amplitude adjustment circuit, and a load.

[0028] The input power supply circuit provides a sinusoidal AC voltage; the rectifier circuit is connected to the output of the input power supply circuit and converts the sinusoidal AC voltage into a sinusoidal absolute value waveform; the voltage amplitude adjustment circuit is connected to the output of the rectifier circuit and switches the operating mode according to the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage to eliminate the input current dead zone and output a stable DC output voltage; the load is connected to the output of the voltage amplitude adjustment circuit to receive the DC output voltage.

[0029] The voltage amplitude adjustment circuit includes a first power switch and a second power switch. The first power switch and the second power switch are connected in parallel with the output terminal of the rectifier circuit. The first power switch and the second power switch are connected in parallel, and the load is connected in parallel with the first power switch and the second power switch.

[0030] The voltage amplitude regulation circuit controls the switching of operating modes by adjusting the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, thereby controlling the on and off states of the first and second power switches to achieve smooth switching between different operating modes.

[0031] The voltage amplitude regulation circuit eliminates the input current dead zone through mode switching, and outputs a stable DC output voltage.

[0032] Specifically, during operation, the input power circuit first provides a sinusoidal AC voltage, which is sent to the rectifier circuit. After processing by the rectifier circuit, the sinusoidal AC voltage is converted into a voltage of absolute value of a sinusoidal waveform, i.e., the absolute value of the output sinusoidal AC voltage. Then, the DC voltage enters the voltage amplitude adjustment circuit. Based on the relationship between the absolute value of the instantaneous value of the input AC voltage and the set DC output voltage, the voltage amplitude adjustment circuit controls the switching of the working mode by controlling the turn-off of the first power switch and the second power switch. While realizing the high-voltage to low-voltage step-down function, it eliminates the input current dead zone to ensure continuous and smooth input current, thereby outputting a stable DC output voltage, which is then sent to the load, where the load receives the DC output voltage.

[0033] The embodiments described above convert sinusoidal AC voltage into DC voltage with an absolute sinusoidal waveform through a rectifier circuit. Combined with the on / off control of the first and second power switches in the voltage amplitude adjustment circuit, adaptive switching of the operating mode is achieved. This not only precisely matches the magnitude relationship between the input DC voltage and the set output voltage, completely eliminating the input current dead zone, but also ensures the stability of the DC output voltage. Furthermore, the non-isolated topology design simplifies the circuit structure, reduces the overall size, and lowers manufacturing costs. It also achieves efficient conversion from high-voltage AC to low-voltage DC without the need for additional magnetic components, combining the advantages of high power factor and low device voltage stress. It is suitable for various high-voltage AC input scenarios and load requirements, significantly improving practicality and reliability.

[0034] It should be noted that the absolute value of the instantaneous value of the sinusoidal AC voltage is indeed the absolute value of the sinusoidal AC voltage. In this application, the rectifier circuit converts the input sinusoidal AC voltage into an instantaneous voltage of a sinusoidal absolute value waveform. In essence, it transforms the alternating positive and negative AC current into a unidirectional pulsating voltage with only positive values ​​and waveforms, i.e., a unidirectional pulsating sinusoidal absolute value voltage. Instead of directly converting the voltage into flat DC, it retains the sinusoidal envelope to provide a unipolar input voltage for the subsequent voltage amplitude adjustment circuit and retains the instantaneous amplitude information of the AC voltage. This allows the subsequent circuit to adjust its operating state according to the magnitude of the instantaneous voltage, achieving dead-zone-free input current and high power factor operation.

[0035] In some specific embodiments of this application, the operating modes include: Buck mode, Boost mode, and a combination of Buck-Boost mode.

[0036] The combinations include Buck mode and Boost mode; Buck mode and Buck-Boost mode; the voltage amplitude regulation circuit switches between Buck mode, Boost mode, and Buck-Boost mode through a first power switch and a second power switch connected in parallel to eliminate the input current dead zone and output a stable DC output voltage.

[0037] The embodiments described above in this application, by employing Buck mode and Buck-Boost mode or a combination of Buck mode and Boost mode in the voltage amplitude adjustment circuit, and switching the working mode according to the input and output voltage conditions, can effectively eliminate the input current dead zone, ensure that a stable DC output voltage can be output under different input voltage conditions, and make the drive circuit simple, easy to implement and inexpensive, thereby providing a reliable and stable power supply to the load and improving the adaptability and stability of the circuit.

[0038] The first and second power switches are connected in parallel, which not only distributes voltage and current stress, reduces device losses and improves the circuit's load capacity, but more importantly, it can form a continuous conduction path by flexibly switching between the on and off states when the instantaneous absolute value of the AC input voltage is close to the critical range of the DC output voltage. This directly eliminates the input current dead zone at the hardware level. At the same time, it can broaden the buck operating range and improve the input current waveform without the need for complex control algorithms, thereby simplifying the control logic and improving the circuit conversion efficiency and operational stability.

[0039] In some specific embodiments of this application, the operating mode switching of the voltage amplitude regulation circuit is controlled by the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, thereby controlling the on and off states of the first power switch and the second power switch, including; When the instantaneous absolute value of the input AC voltage is greater than the DC output voltage, the on / off state of the first power switch and the second power switch is controlled to make the voltage amplitude regulation circuit work in Buck mode; when the instantaneous absolute value of the input AC voltage is less than the DC output voltage, the on / off state of the first power switch and the second power switch is controlled to make the voltage amplitude regulation circuit work in Buck-Boost mode or Boost mode.

[0040] In the embodiments described above, during the operation of the voltage amplitude regulation circuit, the instantaneous value of the absolute value of the input AC voltage and the preset DC output voltage are monitored in real time. When the instantaneous value of the absolute value of the input AC voltage is found to be greater than the value of the DC output voltage, the voltage amplitude regulation circuit automatically switches between the states of the first power switch and the second power switch and operates stably in Buck mode. When the instantaneous value of the absolute value of the input AC voltage is found to be less than the value of the DC output voltage, the voltage amplitude regulation circuit switches between the states of the first power switch and the second power switch to Buck-Boost mode or Boost mode to operate. This allows for flexible adjustment of the operating mode according to different voltage conditions, improving the adaptability and flexibility of the voltage amplitude regulation circuit and meeting the load's demand for stable voltage in different scenarios.

[0041] It should be noted that the output voltage is uo. If uo remains constant, it can be written as Uo. The input voltage is... UI It is a constantly changing sinusoidal voltage. Input voltage UI If the absolute value of the instantaneous value is higher than uo or Uo, Buck mode is used. However, the input voltage... UI When the absolute value of the instantaneous value is lower than uo or Uo, Boost mode is used (for Figure 1 and Figure 2 ) or Buck-Boost mode (for Figure 1 and Figure 2 The output voltage uo is set by the control system, and the input voltage... UI Instantaneous values ​​need to be monitored constantly, so a detection module is not required. After rectification by the rectifier bridge, the voltage after the bridge is... UI The absolute value of is equivalent to the instantaneous value of the voltage after the bridge.

[0042] Reference Figure 1 As shown, in some specific embodiments of this application, the voltage amplitude adjustment circuit further includes: diode De, diode Df, filter inductor La, and filter capacitor Cb.

[0043] When the voltage amplitude adjustment circuit is switching between Buck mode and Boost mode, the cathode of diode De is connected to one end of the filter inductor La, the anode of diode De is connected to the drain of the first power switch Sa and the negative terminal of the filter capacitor Cb, the other end of the filter inductor La is connected to the drain of the second power switch Sb and the anode of diode Df, the cathode of diode Df is connected to the negative terminal of the filter capacitor, the source of the first power switch Sa is connected to the source of the second power switch Sb and grounded, and the load is connected in parallel with the filter capacitor Cb.

[0044] It should be noted that in each mode, a fixed power switch operates according to the mode requirements. The switching rules for different modes are as follows: Figure 2 and Figure 3 As shown. When switching between the two modes, the on / off sequence of Sa and Sb does not need to be considered; operation can proceed according to the mode. Even if Sa and Sb form a bridge arm, the presence of the inductor La allows them to conduct simultaneously for a short period, which may increase the dead time but does not necessarily affect the normal operation of the circuit.

[0045] In some specific embodiments of this application, when the voltage amplitude regulation circuit is operating in Buck mode, the instantaneous absolute value of the input AC voltage is greater than the DC output voltage. The first power switch Sa is controlled to periodically turn on and off, while the second power switch Sb is kept off at all times. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb. When the voltage amplitude regulation circuit switches to Boost mode, the instantaneous absolute value of the input AC voltage is less than the DC output voltage. This controls the first power switch Sa and the power switch to periodically and complementaryly turn on and off, thereby stabilizing the DC output voltage through the filter inductor La and the filter capacitor Cb and eliminating the input current dead zone.

[0046] Specifically, during operation, the voltage amplitude regulation circuit switches modes based on the relationship between the instantaneous absolute value of the input AC voltage and the DC output voltage: When the instantaneous absolute value of the input AC voltage is greater than the DC output voltage, the circuit enters Buck mode. In this mode, the second power switch Sb remains always off, and only the first power switch Sa is periodically turned on and off. That is, when the first power switch Sa is on, the input voltage forms a current loop through La, and La stores energy; when Sa is off, La releases energy to Cb and the load through De freewheeling, which, together with the filtering effect of Cb, stabilizes the DC output voltage. When the instantaneous absolute value of the input AC voltage is less than the DC output voltage, the circuit switches to Boost mode. In this mode, Sa and Sb are periodically and complementaryly turned on and off. That is, when Sb is on, La enters the loop to store energy; when Sb is off, La releases energy through Df and boosts the output voltage. At the same time, the complementary action of Sa optimizes the energy conversion path. Finally, through the energy storage / release of La and the filtering of Cb, a stable DC output is achieved. Moreover, because the current is continuous and uninterrupted in Boost mode, the input current dead zone is effectively eliminated.

[0047] The embodiments described above in this application adaptively select the operating mode based on the relationship between the input and output voltages. In Buck mode, the control logic is simplified by using the fixed shutdown of Sb, and the energy storage and filtering characteristics of La and Cb are used to ensure stable low-voltage output. In Boost mode, the complementary conduction of Sa and Sb eliminates the input current dead zone that is prone to occur in traditional circuits, keeping the input current continuously controllable and significantly improving the power factor correction capability. At the same time, it avoids the power switches from being subjected to excessive voltage stress (e.g., Sa and Sb do not need to bear the superimposed stress of high input voltage and high output voltage at the same time). The two modes are switched by controlling the on and off of two power switches. The drive circuit structure is simple and easy to implement in engineering. There is no need for complex cascading design. It can effectively adapt to load scenarios with high-voltage input and low-voltage power supply (such as electric vehicle charging stations, power adapters, etc.), reducing costs and circuit losses while ensuring output stability.

[0048] Reference Figure 3 As shown, in some specific embodiments of this application, the voltage amplitude adjustment circuit includes: a first power switch Sa, a second power switch Sb, a diode De, a diode Df, a filter inductor La, and a filter capacitor Cb.

[0049] When the voltage amplitude adjustment circuit is switching between Buck mode and Buck-Boost mode, the cathode of diode De is connected to one end of filter inductor La, the anode of diode De is connected to the negative terminal of filter capacitor Cb and the anode of diode Df, the other end of filter inductor La is connected to the positive terminal of filter capacitor Cb and the drain of second power switch Sb, the cathode of diode Df is connected to the drain of first power switch Sa, and the source of second power switch Sb is connected to the source of first power switch Sa and grounded.

[0050] In some specific embodiments of this application, when the voltage amplitude regulation circuit operates in Buck mode, the instantaneous absolute value of the input AC voltage is greater than the DC output voltage. This controls the first power switch Sa to periodically turn on and off, while keeping the second power switch Sb always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb.

[0051] When the voltage amplitude regulation circuit switches to Buck-Boost mode, the instantaneous absolute value of the input AC voltage is less than the DC output voltage. This controls the second power switch Sb to periodically turn on and off, keeping the first power switch Sa always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb, eliminating the input voltage dead zone.

[0052] Specifically, when the voltage amplitude regulation circuit switches between Buck mode and Buck-Boost mode, it adaptively switches modes based on the instantaneous absolute value of the input AC voltage and the magnitude of the DC output voltage. When the instantaneous absolute value of the input AC voltage is greater than the DC output voltage, the circuit enters Buck mode. In this mode, the second power switch Sb remains off, and only Sa is periodically turned on and off. When Sa is on, the input voltage forms a loop through La, where energy is absorbed and stored. When Sa is off, La releases the stored energy to Cb and the load through De, which, together with the filtering effect of Cb, ensures a stable DC output voltage. When the instantaneous absolute value of the input AC voltage is less than the DC output voltage, the circuit switches to Buck-Boost mode. In this mode, the first power switch Sa remains always off, and only Sb is periodically turned on and off. When Sb is on, La is connected to the circuit and stores energy; when Sb is off, La freewheels through Df, releasing energy and raising the output voltage at the same time. After being filtered by Cb, a stable output is achieved. Because the current is continuous and uninterrupted in this mode, the input current dead zone is effectively eliminated.

[0053] Where Sa and Sb represent the first power switch and the second power switch, respectively.

[0054] In the embodiments described above, only a single power switch needs to be controlled (Sa in Buck mode and Sb in Buck-Boost mode) when switching between Buck mode and Buck-Boost mode. The other switch remains fixed off, eliminating the need for complex complementary switching timing design, eliminating input current dead zone, simplifying drive circuit logic, and reducing control difficulty and the risk of failure caused by timing deviation. At the same time, by changing the connection of De and Df, the freewheeling requirements of the two modes are adapted respectively, so that the power switch does not have to bear the superimposed stress of high input voltage and high output voltage, effectively reducing the average voltage stress of the switching transistor, making it easier to select low-cost, high-reliability power devices, improving the power factor correction capability of the circuit, eliminating the need for multi-stage cascade design, and resulting in a compact structure and fewer components. When adapting to high-voltage input and low-voltage power supply scenarios such as electric vehicle charging stations and power adapters, it can ensure output stability while reducing overall cost and circuit losses.

[0055] It should be noted that when the instantaneous value of the input voltage (i.e., the absolute value of the instantaneous value) is lower than the output voltage, the power switch in a traditional Buck-type PFC cannot conduct current, resulting in an interruption of the input current and creating a period with no input current, which is called the input current dead zone. This application introduces a Boost or Buck-Boost mode to maintain the current path in the low-voltage range, thereby achieving continuous current throughout the entire cycle.

[0056] In some specific embodiments of this application, the rectifier circuit includes diodes Da, Db, Dc, Dd, and resistor Ra.

[0057] The cathode of diode Da is connected to the cathode of diode Dc and one end of resistor Ra. The cathode of diode Db is connected to the anode of diode Da. The anode of diode Db is connected to the anode of diode Dd and the other end of resistor Ra, and then grounded. The anode of diode Dc is connected to the cathode of diode Dd. Diodes Dc, the cathode of diode Da, and one end of resistor Ra are connected, and then connected to the cathode of diode De and one end of filter inductor La. The other end of resistor Ra is connected to the source of power switch Sb. Diodes Da and Db are connected to the positive terminal of the power supply circuit, and diodes Dc and Dd are connected to the negative terminal of the input power supply circuit.

[0058] In the above embodiments of this application, four diodes are used to convert the input sinusoidal AC voltage into a sinusoidal absolute value waveform without control, reducing the average voltage stress of the device by half, which facilitates the selection of subsequent power switches, especially for power MOSFETs, where the on-resistance of high-voltage power MOSFETs is too large.

[0059] In some specific embodiments of this application, the input power supply circuit includes a power supply. ui、Electrolytic capacitor Ca, the positive terminal of electrolytic capacitor Ca is connected to the power supply. UI The positive terminal is connected, and the negative terminal of the electrolytic capacitor Ca is connected to the power supply. UI Negative terminal connection; the anode of diode Da and the cathode of diode Db are connected to the positive terminal of electrolytic capacitor Ca, and the cathode of diode Dd and the anode of diode Dc are connected to the negative terminal of electrolytic capacitor Ca.

[0060] In some specific embodiments of this application, the load includes a resistor Rb, the positive terminal of the resistor Rb is connected to the positive terminal of the filter capacitor Cb, and the negative terminal of the load is connected to the negative terminal of the filter capacitor Cb.

[0061] It should be noted that the resistance Rb actually reflects the load. The load can be a resistive load, or a constant power, constant current, constant voltage, or other types of load. The load current can be continuous or discontinuous.

[0062] Reference Figure 5 As shown, based on the same inventive concept, a second aspect of this application provides a modulation method for optimizing the rectifier circuit of a high-performance dynamic voltage restorer, comprising: S1. Obtain a stable sinusoidal AC voltage supplied by the power supply circuit; S2. Input a sinusoidal AC voltage to the rectifier circuit and output a stable sinusoidal absolute value waveform AC voltage instantaneous absolute value voltage. S3. Based on the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, the operating mode is switched by controlling the first and second power switches connected in parallel in the voltage amplitude adjustment circuit to eliminate the input current dead zone and output a stable DC output voltage.

[0063] In the embodiments described above, a stable sinusoidal AC voltage is obtained through a power supply circuit. This sinusoidal AC voltage is then input into a rectifier circuit to obtain an instantaneous absolute value voltage with a sinusoidal absolute value. Subsequently, the magnitude of this absolute value voltage and the DC output voltage are used to drive and control the first and second power switches connected in parallel in the voltage amplitude regulation circuit. By dynamically switching their operating modes, the input current dead zone is eliminated, achieving a stable low-voltage DC output. By controlling the operating mode of the parallel power switches through real-time comparison of the instantaneous absolute value of the AC voltage and the output DC voltage, the generation of the input current dead zone can be accurately and quickly suppressed, improving the AC side current waveform distortion problem, enhancing the circuit power factor and energy conversion efficiency. At the same time, the control logic is simple and intuitive, simplifying the modulation strategy and enhancing the reliability and dynamic response speed of the circuit while ensuring the stability of the DC output voltage.

[0064] The foregoing has described some specific embodiments of this application. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. A high-performance dynamic voltage restorer optimized rectifier circuit, characterized in that, include: Input power circuit, used to provide AC voltage; A rectifier circuit, connected to the output terminal of the input power supply circuit, is used to convert the AC voltage into a voltage with a sinusoidal absolute value waveform; A voltage amplitude adjustment circuit, connected to the output terminal of the rectifier circuit, is used to switch the operating mode according to the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage to eliminate the input current dead zone and output a stable DC output voltage. A load is connected to the output terminal of the voltage amplitude regulation circuit to receive the DC output voltage; The voltage amplitude adjustment circuit includes a first power switch and a second power switch. The first power switch and the second power switch are connected in parallel with the output terminal of the rectifier circuit. The first power switch and the second power switch are connected in parallel, and the load is connected in parallel with the first power switch and the second power switch. The operating mode switching of the voltage amplitude regulation circuit is controlled by the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, thereby controlling the on and off states of the first power switch and the second power switch to achieve smooth switching between different operating modes.

2. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 1, characterized in that, The operating modes include: a combination of Buck mode, Boost mode, and Buck-Boost mode; The combination includes the combination of the Buck mode and the Boost mode; the combination of the Buck mode and the Buck-Boost mode; The voltage amplitude adjustment circuit eliminates the input current dead zone by switching between the Buck mode, the Boost mode, and the Buck-Boost mode through the first power switch and the second power switch connected in parallel, and outputs a stable DC output voltage.

3. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 2, characterized in that, The operating mode switching of the voltage amplitude regulation circuit is controlled by the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, controlling the on and off states of the first power switch and the second power switch, including: When the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage, the on and off states of the first power switch and the second power switch are controlled to make the voltage amplitude adjustment circuit work in Buck mode. When the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage, the on and off states of the first power switch and the second power switch are controlled to make the voltage amplitude adjustment circuit work in Buck-Boost mode or Boost mode.

4. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 3, characterized in that, The voltage amplitude adjustment circuit also includes: diode De, diode Df, filter inductor La, and filter capacitor Cb; When the voltage amplitude adjustment circuit is in the combination switching between Buck mode and Boost mode, the cathode of diode De is connected to one end of the filter inductor La, the anode of diode De is connected to the drain of the first power switch Sa and the negative terminal of the filter capacitor Cb, the other end of the filter inductor La is connected to the drain of the second power switch Sb and the anode of diode Df, the cathode of diode Df is connected to the negative terminal of the filter capacitor, the source of the first power switch Sa is connected to the source of the second power switch Sb and grounded, and the load is connected in parallel with the filter capacitor Cb.

5. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 4, characterized in that, When the voltage amplitude adjustment circuit operates in the Buck mode, the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage. This controls the first power switch Sa to periodically turn on and off, while keeping the second power switch Sb always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb. When the voltage amplitude adjustment circuit switches to the Boost mode, the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage. The first power switch Sa and the power switch are controlled to periodically and complementaryly turn on and off. The DC output voltage is stabilized by the filter inductor La and the filter capacitor Cb, eliminating the input current dead zone.

6. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 4, characterized in that, When the voltage amplitude adjustment circuit is in the combination switching between Buck mode and Buck-Boost mode, the cathode of diode De is connected to one end of the filter inductor La, the anode of diode De is connected to the negative terminal of the filter capacitor Cb and the anode of diode Df, the other end of the filter inductor La is connected to the positive terminal of the filter capacitor Cb and the drain of the second power switch Sb, the cathode of diode Df is connected to the drain of the first power switch Sa, and the source of the second power switch Sb is connected to the source of the first power switch Sa and grounded.

7. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 6, characterized in that, When the voltage amplitude adjustment circuit operates in the Buck mode, the absolute value of the instantaneous value of the input AC voltage is greater than the DC output voltage. This controls the first power switch Sa to periodically turn on and off, while keeping the second power switch Sb always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb. When the voltage amplitude adjustment circuit switches to the Buck-Boost mode, the absolute value of the instantaneous value of the input AC voltage is less than the DC output voltage. This controls the second power switch Sb to periodically turn on and off, keeping the first power switch Sa always off. The DC output voltage is stabilized through the filter inductor La and the filter capacitor Cb, eliminating the input voltage dead zone.

8. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 4, characterized in that, The rectifier circuit includes diodes Da, Db, Dc, and Dd, and resistor Ra. The cathode of diode Da is connected to the cathode of diode Dc and one end of resistor Ra. The cathode of diode Db is connected to the anode of diode Da. The anode of diode Db is connected to the anode of diode Dd and the other end of resistor Ra, and then grounded. The anode of diode Dc is connected to the cathode of diode Dd. Diode Dc, the cathode of diode Da, and one end of resistor Ra are connected, and then connected to the cathode of diode De and one end of filter inductor La. The other end of resistor Ra is connected to the source of power switch Sb. The diodes Da and Db are connected to the positive terminal of the power supply circuit, and the diodes Dc and Dd are connected to the negative terminal of the input power supply circuit.

9. The optimized rectifier circuit for a high-performance dynamic voltage restorer according to claim 8, characterized in that, The input power circuit includes a power supply. ui、 An electrolytic capacitor Ca, wherein the positive terminal of the electrolytic capacitor Ca is connected to the power supply. UI The positive terminal is connected, and the negative terminal of the electrolytic capacitor Ca is connected to the power supply. UI Negative terminal connection; The anode of diode Da and the cathode of diode Db are connected to the positive terminal of electrolytic capacitor Ca, and the cathode of diode Dd and the anode of diode Dc are connected to the negative terminal of electrolytic capacitor Ca.

10. A modulation method for optimizing the rectifier circuit of a high-performance dynamic voltage restorer, characterized in that, include: Obtain a stable sinusoidal AC voltage supplied by the power supply circuit; The sinusoidal AC voltage is input to the rectifier circuit, and the output is the absolute value of the instantaneous AC voltage with a stable sinusoidal absolute value waveform. Based on the absolute value of the instantaneous AC voltage and the magnitude of the DC output voltage, the operating mode is switched by controlling the first and second power switches in the voltage amplitude adjustment circuit to eliminate the input current dead zone and output a stable DC output voltage.

Images