Modular ac voltage regulating device

Abstract

This application belongs to the field of power electronics technology and discloses a modular AC voltage regulator. The device includes: an interface filter module for filtering the input AC voltage and for electrical connection with the external power grid and load; a voltage regulation module for regulating the filtered AC voltage; a control module for sampling the regulated AC voltage and generating drive commands to control the interface filter module and the voltage regulation module to achieve closed-loop voltage regulation; and an output filter module for filtering the regulated AC voltage to smooth the output voltage waveform and stabilize system energy. This application can improve the efficiency of existing AC voltage regulators and features easy expansion and high reliability.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, specifically relating to a modular AC voltage regulator. Background Technology

[0002] With the increasing variety of residential electrical appliances, including induction cookers, electric vehicles, computers, and various battery-powered charging devices, the load characteristics on the user side are shifting from traditional resistive loads to nonlinear loads. Simultaneously, the widespread adoption of distributed photovoltaic (PV) power generation systems has transformed the user side into a source-containing network. PV power generation often adopts a "local consumption, surplus power to the grid" model, injecting electricity into the distribution network after meeting its own electricity needs. Due to factors such as the thinner wire diameter and resistive impedance at the end of distribution lines, the injected PV power can easily lead to voltage increases at the transformer substation, resulting in voltage exceeding limits due to "high voltage during the day and low voltage at night." Load nonlinearity and the integration of new energy sources together pose challenges to the voltage stability of the distribution network.

[0003] To address the aforementioned voltage deviation problem, existing technologies mainly employ the following two methods: one is to adjust the voltage by adjusting the taps on the secondary side of the transformer, but this method cannot achieve continuous voltage regulation and is difficult to adapt to the needs of frequent adjustments; the other is to use a two-stage power electronic conversion topology of rectification (AC) - direct current (DC) - inverter (AC) to achieve voltage regulation, but this scheme has shortcomings such as high equipment loss, large size, and high consumption of non-ferrous metals. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a modular AC voltage regulator. Through modular structural design and flexible bridge arm installation direction, this application can achieve high efficiency, low cost, easy expansion and high reliability of AC voltage regulator.

[0005] To achieve the above objectives, this application provides the following technical solution: A modular AC voltage regulator includes: an interface filter module electrically connected to an external power grid for filtering AC voltage input from the external power grid; a voltage regulation module electrically connected to the interface filter module for regulating the filtered AC voltage; a control module electrically connected to the voltage regulation module for sampling the regulated AC voltage and generating drive commands to drive the interface filter module and the voltage regulation module to achieve closed-loop voltage regulation; and an output filter module electrically connected to the voltage regulation module for filtering the regulated AC voltage to smooth the output voltage waveform.

[0006] Optionally, the interface filtering module includes: an interface filtering circuit board, which is electrically connected to an external power grid via wiring terminals; an input filtering capacitor is provided on the upper end of the interface filtering circuit board, and a reactor group is connected to the lower end, wherein the reactor group and the input filtering capacitor constitute an interface filtering circuit.

[0007] Optionally, the voltage regulation module includes: a power circuit board, on the upper surface of the power circuit board near the interface filter module, multiple driver boards with the same circuit structure are independently arranged, each driver board is vertically soldered and fastened to the power circuit board; the lower surface of the power circuit board is electrically connected to a power semiconductor device through semiconductor pins, and electrical pins are arranged around the pins of the power semiconductor device, and electrically connected to the driver board through copper plating on the printed circuit board.

[0008] Optionally, the driver board is provided with a driver circuit that responds to the driver commands generated by the control module to drive and control the interface filtering module and the voltage regulation module to achieve closed-loop voltage regulation.

[0009] Optionally, the power semiconductor device may be an insulated gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor.

[0010] Optionally, the output filtering module includes an AC capacitor.

[0011] Optionally, the control module includes a control board located above the drive board and fixedly connected to the drive board.

[0012] Optionally, the control board is provided with a signal sampling and processing circuit for sampling the regulated AC voltage and generating drive commands.

[0013] Optionally, the voltage regulation module further includes a heat sink located below the heat dissipation surface of the power semiconductor device.

[0014] Compared with the prior art, the beneficial effects of this application are as follows: 1. This application achieves flexible assembly and functional expansion of the device through the modular structure design of interface filter circuit, modular bridge arm and capacitor, thereby reducing production and maintenance costs; 2. The boost and buck functions of this application can be configured simply by changing the installation direction of the modular bridge arm during the assembly process, without the need to replace hardware, which simplifies the production process and improves applicability. 3. This application can easily expand the device capacity by directly connecting multiple modular bridge arms in parallel and wiring them at equal intervals, thus meeting the application requirements of different power levels. Attached Figure Description

[0015] Figure 1 This is a front view of a modular AC voltage regulator provided in one embodiment of this application; Figure 2 This is a side view of a modular AC voltage regulator provided in another embodiment of this application; Figure 3This is a top view of a modular AC voltage regulator provided in another embodiment of this application; Figure 4 This is a rear view of a modular AC voltage regulator provided in another embodiment of this application; Figure 5 This is a schematic diagram of a bridge arm composed of IGBTs; Figure 6 This is a schematic diagram of a bridge arm composed of MOSFETs; Figure 7 This is a schematic diagram of the boost topology of the voltage regulation module; Figure 8 This is a schematic diagram of the step-down topology of the voltage regulation module; Figure 9 This is a schematic diagram of the circuit structure of the signal sampling and processing circuit; Figure 10 This is a schematic diagram of the drive circuit structure; Figure 11 This is a schematic diagram of the voltage regulator module operating in boost mode. Figure 12 This is a schematic diagram of the voltage regulating module operating in step-down mode.

[0016] Explanation of reference numerals in the attached figures: 1. Interface filter circuit board; 2. Terminal block; 3. Copper busbar; 4. Input filter capacitor; 5. Insulating support; 6. Reactor assembly; 7. Control board; 8. Driver board; 9. AC capacitor; 10. Power circuit board; 11. Power semiconductor device; 12. Heat sink. Detailed Implementation

[0017] Specific embodiments of this application will now be described in detail with reference to the accompanying drawings. While specific embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0018] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0019] To facilitate understanding of the embodiments of this application, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this application.

[0020] Figures 1 to 4 The structure of the modular AC voltage regulator proposed in this application is shown from different perspectives, such as... Figures 1 to 4 As shown, the device includes: an interface filtering module, electrically connected to an external power grid, for filtering the AC voltage input from the external power grid; a voltage regulating module, electrically connected to the interface filtering module, for regulating the filtered AC voltage; a control module, electrically connected to the voltage regulating module, for sampling the regulated AC voltage and generating drive commands to control the interface filtering module and the voltage regulating module to achieve closed-loop voltage regulation; and an output filtering module, electrically connected to the voltage regulating module, for filtering the regulated AC voltage to smooth the output voltage waveform.

[0021] In this embodiment, the interface filtering module effectively suppresses high-frequency interference and surge current on the grid side by filtering the input AC voltage, providing a clean and stable input voltage foundation for subsequent voltage regulation. The voltage regulation module chops and adjusts the amplitude of the filtered AC voltage, enabling flexible boost or buck functions without hardware replacement, which improves the adaptability and regulation efficiency of the device. The control module samples the output voltage in real time and generates drive commands to form a voltage closed-loop regulation mechanism, ensuring output accuracy and dynamic response speed, enabling the device to maintain a stable voltage output under various load conditions. The output filtering module smooths the regulated AC voltage, further reducing the switching ripple and harmonic content in the output voltage, thereby obtaining a purer and smoother AC sine wave waveform, which improves power supply quality and the operational safety of the load equipment.

[0022] In another exemplary embodiment, by Figures 1 to 4 As can be seen, the interface filtering module includes an interface filtering circuit board 1, which is electrically connected to the external power grid through a terminal block 2. An input filtering capacitor 4 is provided on the upper end of the interface filtering circuit board 1, and a reactor group 6 is connected to the lower end through an insulating support 5. The reactor group 6 and the input filtering capacitor 4 constitute the interface filtering circuit.

[0023] In this embodiment, the AC voltage from the external power grid is first introduced into the interface filter circuit board 1 through the terminal 2. The input filter capacitor 4, connected in parallel between the live wire and the neutral wire, performs initial filtering of high-frequency interference and surge current in the AC voltage to suppress grid-side conducted noise from entering the subsequent voltage regulation stage. Subsequently, the filtered AC voltage undergoes energy storage and current smoothing through the reactor group 6 supported by the insulating support 5 to complete input-side electrical isolation and power transmission. At the same time, the interface filter circuit also achieves reliable electrical connection between the device and the external power grid and load through the terminal 2, thus forming a complete path of "input filtering - energy storage / smoothing - electrical interface" in physical structure, providing a clean and stable input voltage for the subsequent voltage regulation module, and ensuring the compatibility and safety between the system and the external power network.

[0024] In another exemplary embodiment, by Figures 1 to 4 It can be seen that the voltage regulation module includes a power circuit board 10. Multiple driver boards 8 with the same circuit structure are independently set on the upper end face of the power circuit board 10 near the interface filter module. Each driver board 8 is vertically soldered and fastened to the power circuit board 10. The lower end face of the power circuit board 10 is electrically connected to a power semiconductor device 11 through semiconductor pins. Electrical pins are arranged around the pins of the power semiconductor device 11 and are electrically connected to the driver board 8 through copper plating on the printed circuit board.

[0025] In this embodiment, the power semiconductor device 11 is mainly responsible for chopping and regulating the AC voltage. Multiple independent driver boards 8, which are vertically soldered and fastened on the upper surface of the power circuit board 10 near the interface filter module, are responsible for receiving pulse width modulation (PWM) control commands from the control board 7 and converting them into switching signals with sufficient driving power. These signals are then used to directly drive the power semiconductor devices to turn on and off through external electrical pins arranged around the pins of the power semiconductor devices via copper plating on the printed circuit board. This vertical stacking and proximity wiring design offers the following technical advantages: First, the extremely short electrical path between the driver board 8 and the power semiconductor devices, achieved through copper-clad connections, reduces parasitic inductance and resistance in the drive circuit, lowers voltage spikes and oscillations during switching, and helps improve the reliability of high-frequency switching operation. Second, multiple independent driver boards 8 correspond to different power semiconductor devices or bridge arms, achieving electrical isolation and fault partitioning of drive signals. A fault in one drive channel will not affect other channels, enhancing the system's fault tolerance and maintainability. Third, the vertically welded mechanical structure allows the driver board 8 to stand firmly on the power circuit board 10, facilitating heat dissipation and convection cooling while saving horizontal mounting area and increasing the device's power density. Fourth, electrical connections via copper-clad printed circuit boards avoid additional wiring harness connections, simplifying the assembly process and reducing the risk of poor contact.

[0026] In another exemplary embodiment, a drive circuit is provided on the drive board, such as... Figure 10 As shown, the driving circuit includes: NMOS transistor Q1, PMOS transistor Q2, insulated gate bipolar transistor Q3, twelfth resistor R12, thirteenth resistor R13, fourteenth resistor R14, fifteenth resistor R15, sixteenth resistor R16, seventeenth resistor R17, fifth capacitor C5, sixth capacitor C6, third Zener diode D3, fourth Zener diode D4, first Zener diode ZD1, second Zener diode ZD2, Schmitt trigger IC (e.g., 74HC14D), and optocoupler OC (e.g., ACPL-332J-500E). The first Zener diode of the twelfth resistor R12... The first terminal receives the drive signal PWM_in, the second terminal is connected to the first terminal of the fifth capacitor C5, and the second terminal of the fifth capacitor C5 is connected to the fourth ground terminal GND4; the power supply pin VCC of the Schmitt trigger IC is connected to the +5V power supply, the ground pin GND is connected to the fifth ground terminal GND5, the output pin 1Y is connected to the anode ANODE of the optocoupler OC via the thirteenth resistor R13, and the cathode CATHODE of the optocoupler OC is connected to the seventh ground terminal GND7; the first power supply pin VCC1 of the optocoupler OC is connected to the +5V power supply (primary side power supply), the second power supply pin VCC2 is connected to the +15V power supply (secondary side positive power supply), and the negative terminal... The source pin VEE is connected to the -8V power supply (negative secondary power supply). The desaturation detection pin DESAT is connected to the cathode of the third Zener diode D3. The anode of the third Zener diode D3 is connected to the cathode of the fourth Zener diode D4. The anode of the fourth Zener diode D4 is connected to the collector of the insulated-gate bipolar transistor Q3. The fault status feedback pin #FAULT of the optocoupler OC is pulled up to the +5V power supply via the fourteenth resistor R14 and is also connected to the fault detection input terminal of control board 7. The output pin VOUT is connected to the gates of both NMOS transistor Q1 and PMOS transistor Q2 via the fifteenth resistor R15. The gate of NMOS transistor Q1... The source is connected to the source of PMOS transistor Q2. The drains of NMOS transistor Q1 and PMOS transistor Q2 are connected to the +15V power supply and the -8V power supply, respectively. The common terminal of their sources is connected to the gate of insulated gate bipolar transistor Q3 through the sixteenth resistor R16. The seventeenth resistor R17 is connected across the gate and emitter of insulated gate bipolar transistor Q3. The first Zener diode ZD1 and the second Zener diode ZD2 are connected in reverse series between the gate and emitter of insulated gate bipolar transistor Q3. The first terminal of the sixth capacitor C6 is connected to the first power supply pin VCC1 of optocoupler OC, and the second terminal is connected to the sixth ground terminal GND6.

[0027] In this embodiment, the pulse width modulation drive signal PWM_in from the control module is first filtered by an RC low-pass network composed of the twelfth resistor R12 and the fifth capacitor C5 to remove high-frequency noise, and then sent to the input terminal of the Schmitt trigger IC (74HC14D). The Schmitt trigger shapes the waveform of the drive signal to eliminate edge jitter and outputs a steep rectangular wave. The waveform-shaped drive signal is then current-limited by the thirteenth resistor R13 and sent to the anode of the optocoupler OC. The optocoupler electrically isolates the low-voltage control signal on the primary side and transmits it to the secondary side. The drive square wave signal generated by the secondary side output pin VOUT (jumping between +15V and -8V) drives the complementary push-pull amplifier circuit composed of NMOS transistor Q1 and PMOS transistor Q2 simultaneously through the fifteenth resistor R15. When the input is high, NMOS transistor Q1 is turned on and PMOS transistor Q2 is turned off, outputting a positive voltage of +15V; when the input is low, NMOS transistor Q1 is turned off and PMOS transistor Q2 is turned on, outputting a negative voltage of -8V. The drive signal output from the push-pull circuit is current-limited by the sixteenth resistor R16 and then sent to the gate of the insulated-gate bipolar transistor Q3. The seventeenth resistor R17 provides a charge discharge path for the gate of Q3, ensuring reliable turn-off. The first Zener diode ZD1 and the second Zener diode ZD2, connected in reverse series, clamp the gate-emitter voltage of Q3 within a safe range to prevent overvoltage breakdown. At the same time, the optocoupler OC monitors the collector of Q3 in real time through the desaturation detection pin DESAT via the third Zener diode D3 and the fourth Zener diode D4 connected in series. - Emitter saturation voltage: When a short circuit or overcurrent occurs in Q3, causing an abnormal rise in the collector voltage and the voltage of the desaturation detection pin DESAT exceeds the internal threshold, the optocoupler OC internally initiates protection. On one hand, it pulls the fault status feedback pin #FAULT low, pulls it up to +5V through the fourteenth resistor R14, and sends a low-level fault signal to the control board 7. On the other hand, it slowly turns off Q3 to suppress the turn-off spike. The sixth capacitor C6 is connected in parallel between the primary power supply pin VCC1 and the sixth ground terminal GND6 of the optocoupler for decoupling filtering. The seventh capacitor C7 is connected in parallel between VCC2 and VEE to provide energy storage and filtering for the secondary dual power supply. The eighth capacitor C8 is connected in parallel between VOUT and VEE to filter out high-frequency glitches in the drive output. The ninth capacitor C9 is connected in parallel between DESAT and VEE to prevent false triggering during normal turn-on, thus achieving reliable drive and complete protection for Q3.

[0028] The key features of this driver circuit are: by using a Schmitt trigger IC to shape the waveform of the input PWM signal, edge jitter and noise interference that may be introduced during control signal transmission can be eliminated, providing a clean and steep drive pulse for the subsequent optocoupler; by selecting an optocoupler OC with electrical isolation function, complete isolation between the primary low-voltage control circuit and the secondary high-voltage drive circuit can be achieved; simultaneously, utilizing its built-in desaturation detection (DESAT) and fault feedback (#FAULT) functions, an intelligent drive architecture with short-circuit and overcurrent protection capabilities can be constructed; the secondary side uses a complementary push-pull amplifier circuit composed of NMOS transistor Q1 and PMOS transistor Q2, coupled with a +15V and -8V dual power supply, enabling the drive output signal to switch rapidly between positive and negative voltages. Specifically, the positive +15V voltage can reliably turn on the insulated-gate bipolar transistor Q3, while the negative -8V voltage can forcibly turn off Q3 and provide... Effectively suppresses the risk of false turn-on caused by Miller capacitance coupling; the seventeenth resistor R17 connected between the gate and emitter of Q3 provides a discharge path for the gate charge, which can further improve the turn-off reliability. The first Zener diode ZD1 and the second Zener diode ZD2 connected in reverse series form a bidirectional clamping circuit, which can strictly limit the gate-emitter voltage within a safe range and prevent overvoltage breakdown. In addition, the sixth capacitor C7 connected in parallel between the primary power supply VCC1 of the optocoupler and ground can realize primary-side decoupling. The seventh capacitor C6 connected in parallel between the secondary positive power supply VCC2 and the negative power supply VEE can provide dual power supply energy storage and high-frequency filtering. The eighth capacitor C8 connected in parallel between the output VOUT and VEE can filter out high-frequency glitches in the drive signal. The ninth capacitor C9 connected in parallel between DESAT and VEE can set the blanking time of desaturation detection to avoid false triggering of protection when the collector voltage has not dropped at the moment of normal turn-on of Q3.

[0029] Based on the above structural characteristics, this driving circuit can achieve the following technical effects: First, the combination of the Schmitt trigger and the push-pull amplifier circuit makes the driving waveform edge steep and the transmission delay small, ensuring the fast response and low switching loss of the insulated gate bipolar transistor Q3 in high-frequency switching state; Second, the electrical isolation provided by the optocoupler effectively blocks the interference of large voltage and large current on the secondary side to the primary side control circuit, which can improve the system's immunity and safety; Third, the intelligent protection mechanism composed of DESAT and #FAULT can complete fault detection, signal feedback and soft shutdown within microseconds when Q3 experiences a short circuit or overcurrent, which not only prevents device damage but also suppresses turn-off overvoltage spikes; Fourth, + The combination of 15V / -8V dual power supply and bidirectional gate clamping circuit helps eliminate the risk of false turn-on caused by the Miller effect, making it suitable for hard-switching applications with high dv / dt. Fifth, the reasonable configuration of the seventeenth resistor R17 and multiple decoupling and filtering capacitors gives the drive circuit good electromagnetic compatibility characteristics, reducing external radiation and improving its own anti-interference capability. Sixth, the overall circuit achieves multiple functions such as isolated drive, waveform shaping, push-pull amplification, overcurrent protection, and gate clamping with a small number of discrete components. It has a compact structure, controllable cost, and is easy to modularly integrate, providing a strong guarantee for the safe, efficient, and reliable operation of power semiconductor devices in modular AC voltage regulators.

[0030] In another embodiment, the output filtering module includes an AC capacitor 9, which is located on the side of the control board 7 away from the drive board 8 and is electrically connected to the power circuit board 10 via a copper busbar 3.

[0031] In this embodiment, the output filtering module uses a single AC capacitor design, which has the following advantages: First, it simplifies the circuit topology, reduces the need for voltage equalization or current equalization auxiliary circuits required for parallel or series capacitor banks, reduces the number of components and failure points in the system, thereby improving the overall reliability. Second, a single capacitor can avoid the circulating current or uneven voltage distribution problems caused by inconsistent parameters when multiple capacitors are connected in parallel, making the output filtering characteristics more stable and predictable. In addition, a single capacitor occupies less space on the printed circuit board, which is conducive to modular and compact layout, and is particularly suitable for AC voltage regulation devices of small and medium power levels, achieving both economy and practicality without affecting the output voltage smoothing effect.

[0032] In another embodiment, the control module includes a control board 7, which is located above the drive board 8 and soldered to the drive board 8 via connectors. The control board 7 is provided with a signal sampling and processing circuit for sampling the regulated AC output voltage.

[0033] In this embodiment, the signal sampling and processing circuit on the control board 7 first samples and processes the output AC voltage to generate pulse width modulation (PWM) control commands. These commands are directly transmitted to the driver board 8 below via connectors. After receiving the commands, the driver board 8 converts them into drive signals adapted to the power semiconductor devices to control the switching of transistors VT1~VT4 in the voltage regulation module, thereby achieving boost or buck regulation of the AC voltage. This compact stacked design has the following technical effects: First, it can shorten the transmission path between the control signal and the drive signal, reduce signal delay and electromagnetic interference, and improve control accuracy and anti-interference capability; second, the rigid connection through connector welding enhances the overall mechanical strength and shock resistance of the module; third, separating the control and drive functions facilitates modular debugging, maintenance and replacement of the circuit, improving the manufacturability and reliability of the device.

[0034] In another exemplary embodiment, such as Figure 9As shown, the signal sampling and processing circuit includes: a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first Zener diode D1, and a second Zener diode D2. The first terminal of the first resistor R1 is connected to the positive sampling input Vin+ (i.e., the control board). The first terminal of the second resistor R2 is connected to the sampling input Vin- (i.e., the input terminal on control board 7 marked as used to acquire the positive signal of the output voltage), and the second terminal is connected to the inverting input terminal of the first operational amplifier U1; the third resistor R3 and the first capacitor C1 are connected in parallel between the non-inverting input terminal of the first operational amplifier U1 and the first ground terminal GND1; the fourth resistor R4 and the second capacitor C2 are connected in parallel between the inverting input terminal of the first operational amplifier U1 and the second ground terminal GND2. The fifth resistor R5 is connected between the inverting input and output of the first operational amplifier U1; the output of the first operational amplifier U1 is connected to the non-inverting input of the second operational amplifier U2 via the sixth resistor R6; the non-inverting input of the second operational amplifier U2 is connected to the reference voltage VREF (usually the ADC half-range voltage, such as 2.5V) via the seventh resistor R7; the eighth resistor R8 and the third capacitor C3 are connected in parallel between the inverting input and output of the second operational amplifier U2; the output of the second operational amplifier U2 is connected to the non-inverting input of the third operational amplifier U3 via the ninth resistor R9. The inverting input of the third operational amplifier U3 is shorted to its output. The output of the third operational amplifier U3 is connected to the first end of the tenth resistor R10, and the second end of the tenth resistor R10 is connected to the first end of the eleventh resistor R11. The second end of the eleventh resistor R11 serves as the output of the final sampling signal Vout. The first end of the fourth capacitor C4 is connected to the junction of the tenth resistor R10 and the eleventh resistor R11, and the second end is connected to the third ground terminal GND3. The first Zener diode D1 and the second Zener diode D2 are connected in series between the second end of the eleventh resistor R11 and the third ground terminal GND3.

[0035] In this embodiment, the signal sampling and processing circuit first sends the differential input AC voltage signals (Vin+, Vin-) to the non-inverting and inverting input terminals of the first operational amplifier U1, respectively, through the first resistor R1 and the second resistor R2. Common-mode noise is filtered using two parallel RC networks consisting of the third resistor R3, the first capacitor C1, and the fourth resistor R4 and the second capacitor C2. The differential amplification factor is set by the fifth resistor R5, conditioning the input signal into a single-ended signal based on the system reference ground. This single-ended signal is then sent to the non-inverting input terminal of the second operational amplifier U2 via the sixth resistor R6. Simultaneously, the reference voltage VREF (e.g., 2.5V) is also connected to this non-inverting input terminal via the seventh resistor R7. Together with the parallel RC feedback network consisting of the eighth resistor R8 and the third capacitor C3, this network elevates the signal level and performs low-pass filtering, thereby shifting the zero level of the AC signal to the center of the ADC range. Next, the output signal of the second operational amplifier U2 enters the third operational amplifier U3 through the ninth resistor R9. Since the inverting input terminal and the output terminal of the third operational amplifier U3 are directly shorted to form a voltage follower, it plays the role of impedance transformation and signal buffering without changing the voltage amplitude. Subsequently, the output of the third operational amplifier U3 passes through an RC low-pass filter composed of the tenth resistor R10, the eleventh resistor R11 and the fourth capacitor C4 to further filter out high-frequency noise and obtain the final sampling signal Vout. Finally, the first Zener diode D1 and the second Zener diode D2, which are connected in series, are connected in reverse series between the eleventh resistor R11 and the third ground terminal GND3. The breakdown characteristics of the Zener diodes are used to clamp the voltage amplitude of the final sampling signal Vout within a safe range (e.g., -5.8V to +5.8V), thereby protecting the input terminal of the subsequent ADC from damage caused by excessively high or low voltages.

[0036] In another exemplary embodiment, the power semiconductor device 11 employs an insulated gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor.

[0037] In this embodiment, for example, the power semiconductor device 11 includes VT1 to VT4, wherein VT1 and VT2 are connected in series to form a first bridge arm, VT3 and VT4 are connected in series to form a second bridge arm, and the first bridge arm and the second bridge arm form a rectifier bridge arm structure.

[0038] It should be noted that the power semiconductor device in this application can be adopted. Figure 5 The IGBT (Insulated Gate Bipolar Transistor) shown is... Figure 6The diagram shows either of two fully controllable MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) devices. When using an IGBT, the emitters of the two devices in each arm are interconnected. Leveraging the IGBT's high voltage withstand capability and low on-state voltage drop, it is suitable for AC voltage regulation applications with higher voltage levels or medium switching frequencies. When using a MOSFET, the sources of the two devices in each arm are interconnected. Utilizing the MOSFET's fast switching speed and lack of tail current, it is suitable for voltage regulation applications with lower voltage levels and higher switching frequencies. The modular arm designs for both devices maintain consistency in external terminal definitions and installation methods, allowing for flexible selection based on actual voltage levels, switching frequencies, and cost requirements, enhancing the device's applicability and configurability.

[0039] Figure 7 The equivalent circuit structure of the AC boost mode composed of the power semiconductor device 11 and the aforementioned modules is shown. Figure 7 In this circuit, Ui is defined as the input AC voltage, and Uo is defined as the output AC voltage. The reactor group 6 in the interface filter circuit includes a first reactor L1 and a second reactor L2. Power semiconductor devices VT1 and VT2 are connected in series to form the first bridge arm, and VT3 and VT4 are connected in series to form the second bridge arm. The first bridge arm and the second bridge arm are connected in parallel between the live wire A and the neutral wire N. The input-side filter capacitor Ci (i.e., the input filter capacitor 4 in the interface filter circuit) and the output-side capacitor Co (i.e., the AC capacitor 9 of the output filter module) are also connected in parallel between the live wire A and the neutral wire N. The first end of the first reactor L1 is connected to the first end of the input-side capacitor Ci, and the second end of the first reactor L1 is connected to the connection point between the first bridge arm and the second bridge arm. The first end of the second reactor L2 is led out as the output end, and the second end is connected to the connection point between the first end of the output-side capacitor Co and the second bridge arm.

[0040] Figure 7The circuit structure shown can achieve AC boost operation as follows: When the input AC voltage Ui is in the positive half-cycle, VT2 in the first bridge arm is turned on, allowing the first reactor L1 to store energy; then VT2 is turned off and VT1 is turned on. The electromotive force stored in the first reactor L1 is superimposed on the input voltage Ui, and charges the output capacitor Co through the anti-parallel diode of VT3 in the second bridge arm, thereby obtaining a DC bus voltage higher than the input voltage at the output terminal. After inverter control, the output AC voltage Uo is generated; during the negative half-cycle, VT1, VT2, and VT4 work together to achieve a symmetrical boost chopping process. This circuit structure offers the following technical advantages: First, it enables single-stage non-isolated AC direct boost, avoiding the efficiency loss caused by two-stage AC-DC-AC conversion; second, the input and output capacitors are connected in parallel to the same pair of buses, effectively suppressing the bidirectional propagation of switching ripple; third, the first reactor L1 and the second reactor L2 have clearly defined functions, respectively undertaking energy storage and boosting and output smoothing functions, reducing the stress requirements of a single inductor and facilitating modular design and increased power density.

[0041] Figure 8 The equivalent circuit structure of the AC boost mode composed of the power semiconductor device 11 and the aforementioned modules is shown. Figure 8 In the text, the parameters are defined as follows: Figure 8 As shown, power semiconductor devices VT1 and VT2 are connected in series to form the first bridge arm, and VT3 and VT4 are connected in series to form the second bridge arm. The first and second bridge arms are connected in parallel between the live wire A and the neutral wire N. The input-side filter capacitor Ci and the output-side capacitor Co are also connected in parallel between the live wire A and the neutral wire N. The first end of the first reactor L1 is connected to the connection point of the first bridge arm and the second bridge arm, and the second end of the first reactor L1 is connected to the first end of the second reactor L2. The second end of the second reactor L2 is led out as the output terminal. The first end of the output-side capacitor Co is connected to the connection point of the first inductor and the second reactor L2.

[0042] Figure 8The circuit structure shown works as follows to achieve AC voltage reduction: When the input AC voltage Ui is in the positive half-cycle, VT1 in the first bridge arm is turned on and VT2 is turned off. The input voltage supplies power to the output side through the first bridge arm, the first reactor L1, and the second reactor L2, while simultaneously charging the output capacitor Co. When VT1 is turned off and VT2 is turned on, the energy stored in the first reactor L1 and the second reactor L2 continues to supply current to the load through VT2 freewheeling, thereby obtaining a chopped average value at the output that is lower than the input voltage, thus achieving the voltage reduction function. During the negative half-cycle, VT3 and VT4 work symmetrically to complete the reduction. This circuit structure offers the following technical advantages: First, the first reactor L1 and the second reactor L2 operate in series, jointly undertaking energy storage and filtering functions. Compared to a single-inductor scheme, this reduces the ripple current stress of a single inductor and improves the smoothness of the output waveform. Second, the output capacitor Co is connected between the series node of the first reactor L1 and the second reactor L2 and the neutral line, forming a π-type filter structure, which enhances the attenuation capability of high-frequency harmonics. Third, the input filter capacitor Ci and the output filter capacitor Co are connected in parallel to the same pair of buses, effectively isolating the bidirectional interference of the bridge arm switching action on the power grid and the load, and improving electromagnetic compatibility performance.

[0043] Figure 11 This is a schematic diagram of the voltage regulator module operating in boost mode. In this diagram, the modular bridge arm is installed in the device in a specific direction, and its U1 terminal is directly connected to the output position of the interface filter circuit for energy transfer. In boost mode, the input voltage stores energy through the first reactor L1, and is then superimposed with the electromotive force generated by the switching action of the power semiconductor device. Through the on / off control of the modular bridge arm, the output voltage amplitude is made higher than the input voltage.

[0044] Figure 12 This is a schematic diagram of the buck converter module in buck mode. In this diagram, the modular bridge arm is reversed in installation direction compared to the boost mode, and its U2 terminal is connected to the output of the interface filter circuit. In buck mode, the input voltage is chopped by power semiconductor devices and then filtered by the first reactor L1 and the second reactor L2, resulting in an output voltage amplitude lower than the input voltage. Switching between boost and buck functions can be achieved simply by changing the installation direction of the modular bridge arm; no hardware replacement is required.

[0045] In another exemplary embodiment, the voltage regulation module further includes a heat sink 12 located below the heat dissipation surface of the power semiconductor device 11.

[0046] In this embodiment, the power semiconductor device generates a large amount of heat during operation due to high-frequency switching. Its heat dissipation surface is in close contact with the upper surface of the heat sink (typically by filling tiny gaps with thermal grease or thermal pads). The heat is conducted through the metal substrate of the heat sink to its fin structure and then dissipated into the surrounding environment through natural convection or forced air cooling. The technical advantage of this heat dissipation layout is that placing the heat sink directly below the power semiconductor device fully utilizes vertical space, avoids heat accumulation on the circuit board, shortens the heat conduction path, and reduces the device junction temperature. This improves the current output capability and long-term operational reliability of the voltage regulator module, ensuring the thermal stability of the voltage regulator under full-load conditions.

[0047] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be construed as limiting the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit and essence of this application should be included within the scope of protection of this application.

Claims

1. A modular AC voltage regulator, characterized in that, The device includes: The interface filtering module is electrically connected to the external power grid and is used to filter the AC voltage input from the external power grid. The voltage regulation module is electrically connected to the interface filter module and is used to regulate the filtered AC voltage. The control module, which is electrically connected to the voltage regulation module, is used to sample the regulated AC voltage and generate drive commands to drive the control interface filter module and the voltage regulation module to achieve closed-loop voltage regulation. The output filtering module, electrically connected to the voltage regulation module, is used to filter the regulated AC voltage to smooth the output voltage waveform.

2. The modular AC voltage regulating device of claim 1, wherein, The interface filtering module includes: The interface filter circuit board is electrically connected to the external power grid via wiring terminals. The upper end of the interface filter circuit board is equipped with an input filter capacitor, and the lower end is connected to a reactor group. The reactor group and the input filter capacitor constitute the interface filter circuit.

3. The modular AC voltage regulating device of claim 1, wherein, The voltage regulating module includes: The power circuit board has multiple driver boards with the same circuit structure independently set on the upper side of the power circuit board near the interface filter module. Each driver board is vertically soldered and fastened to the power circuit board. The lower end of the power circuit board is electrically connected to a power semiconductor device via semiconductor pins, and electrical pins are arranged around the pins of the power semiconductor device, and are electrically connected to the driver board via copper plating on the printed circuit board.

4. The modular AC voltage regulating device of claim 3, wherein, The driver board is equipped with a driver circuit that responds to the driver commands generated by the control module to drive and control the interface filter module and the voltage regulation module to achieve closed-loop voltage regulation.

5. The modular AC voltage regulating device of claim 3, wherein, The power semiconductor device is an insulated gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor.

6. The modular AC voltage regulating device of claim 1, wherein, The output filtering module includes an AC capacitor.

7. The modular AC voltage regulating device of claim 3 or 4, wherein, The control module includes: The control board is located above the drive board and is fixedly connected to the drive board.

8. The modular AC voltage regulating device of claim 7, wherein, The control panel is equipped with: The signal sampling and processing circuit is used to sample the regulated AC voltage and generate drive commands.

9. The modular AC voltage regulating device of claim 3, wherein, The voltage regulating module also includes: The heat sink is located below the heat dissipation surface of the power semiconductor device.

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