AC-AC solid state voltage regulating device based on sic mos and control method thereof

Abstract

The application relates to the technical field of AC-AC solid-state voltage regulation, in particular to an AC-AC solid-state voltage regulation device based on SiCMOS and a control method thereof, which comprises an AC-AC power conversion circuit, a working mode switching circuit and a voltage regulation control circuit; the AC-AC power conversion circuit is composed of SiCMOS power devices, an inductor L and a capacitor C and is used for realizing efficient energy transmission; the input end of the working mode switching circuit is connected with the control end of the AC-AC power conversion circuit and is used for realizing the switching of the input voltage reduction, input voltage increase and bypass operation modes according to the input voltage range; and the output end of the voltage regulation control circuit is connected with the control ends of the AC-AC power conversion circuit and the working mode switching circuit. The application adopts SiCMOS power devices to construct the AC-AC power conversion circuit, compared with traditional silicon controlled rectifier devices, has the advantages of fast switching speed, small conduction resistance and low switching loss, can realize millisecond-level response output of voltage, and has higher regulation precision.

Description

Technical Field

[0001] This invention relates to the field of AC-AC solid-state voltage regulation technology, specifically to an AC-AC solid-state voltage regulation device and its control method based on SiCMOS. Background Technology

[0002] Solid-state voltage regulators, also known as power electronic voltage regulators, are contactless electronic voltage regulators that use power electronic devices to regulate AC voltage. Unlike traditional autotransformers or voltage regulators based on mechanical contacts, solid-state voltage regulators have no moving parts. They effectively regulate the AC voltage across the load by controlling the switching of power electronic switching devices.

[0003] Traditional solid-state voltage regulators mostly use thyristors as power switching devices, which have disadvantages such as slow response speed, high switching losses, and low operating frequency. In recent years, with the development of wide bandgap semiconductor technologies such as silicon carbide (SiC), SiCMOS transistors have gradually become the preferred power devices for power electronic converters due to their advantages such as fast switching speed, low on-resistance, high temperature resistance, and high voltage resistance.

[0004] However, existing SiCMOS-based AC-AC solid-state voltage regulation devices still have the following problems: (1) Most of them can only achieve a single step-down or step-up function, and cannot automatically switch the working mode according to the input voltage range, and the voltage regulation range is limited; (2) The heat dissipation structure is not designed properly. The heat-generating components such as SiCMOS transistors and power inductors are concentrated in one place, resulting in poor heat dissipation and affecting the service life and reliability of the device. Summary of the Invention

[0005] To address the problems mentioned in the background section, the present invention provides the following technical solution: A SiCMOS-based AC-AC solid-state voltage regulator includes an AC-AC power conversion circuit, an operating mode switching circuit, and a voltage regulation and control circuit. The AC-AC power conversion circuit consists of SiCMOS power devices, inductor L, and capacitor C, and is used to achieve efficient energy transfer. The input terminal of the operating mode switching circuit is connected to the control terminal of the AC-AC power conversion circuit, and is used to switch the input voltage buck, boost and bypass operation modes according to the input voltage range. The output terminal of the voltage regulation control circuit is connected to the control terminals of the AC-AC power conversion circuit and the working mode switching circuit, respectively, to achieve a fast and accurate response to the input voltage according to the output voltage requirements.

[0006] Preferably, the AC-AC power conversion circuit adopts a bidirectional Buck-Boost topology, including: The first SiCMOS transistor and the second SiCMOS transistor are connected in reverse series to form the first bidirectional switch, one end of which is connected to the live wire of the input AC power supply. The third SiCMOS transistor and the fourth SiCMOS transistor are connected in reverse series to form a second bidirectional switch, one end of which is connected to the neutral terminal of the input AC power supply. The energy storage inductor is connected between the common terminal of the first and second bidirectional switches; The fifth SiCMOS transistor and the sixth SiCMOS transistor are connected in reverse series to form a third bidirectional switch. One end of the switch is connected to the other end of the first bidirectional switch, and the other end is connected to the live wire of the output terminal. The output filter capacitor is connected between the live wire and the neutral wire at the output terminal. The other end of the first bidirectional switch is also connected to the neutral terminal of the output terminal through a seventh SiCMOS transistor, and the other end of the second bidirectional switch is also connected to the live terminal of the output terminal through an eighth SiCMOS transistor.

[0007] Preferably, the operating mode switching circuit includes a voltage sampling unit, a mode judgment unit, and a switch driving unit; The input terminal of the voltage sampling unit is connected to the input AC power supply and the output terminal respectively, and is used to collect the input voltage and output voltage signals. The input terminal of the mode determination unit is connected to the output terminal of the voltage sampling unit, and is used to determine the current working mode based on the collected voltage signal. The input terminal of the switch driving unit is connected to the output terminal of the mode judgment unit, and the output terminal is connected to the gate of each of the SiCMOS transistors, which is used to drive the corresponding SiCMOS transistors to turn on or off according to the mode judgment result.

[0008] Preferably, the voltage regulation control circuit includes an error amplifier, a PWM modulator, and a drive isolation unit; The input terminals of the error amplifier are respectively connected to the reference voltage and the output voltage feedback signal output by the voltage sampling unit, which are used to compare the output voltage with the reference voltage and generate an error signal; The input terminal of the PWM modulator is connected to the output terminal of the error amplifier, and is used to generate a PWM control signal with a corresponding duty cycle according to the error signal; The input terminal of the drive isolation unit is connected to the output terminal of the PWM modulator, and the output terminal is connected to the control terminal of the switch drive unit, which is used to isolate and amplify the PWM control signal.

[0009] Preferably, it further includes a layered heat dissipation structure, the layered heat dissipation structure comprising: The casing is internally divided into air ducts and a sealed enclosure by partitions. The air duct has an IP54 protection rating and is equipped with an air inlet and an air outlet. Multiple parallel cooling fans are installed inside the air duct. The enclosed enclosure has an IP65 protection rating and is used to install circuit board assemblies. An auxiliary cooling fan is installed inside the enclosed enclosure.

[0010] Preferably, the SiCMOS power device in the AC-AC power conversion circuit is mounted on a MOSFET heat sink, and the MOSFET heat sink is connected to the SiCMOS power device through an alumina ceramic sheet. The MOSFET heat sink is located inside the air duct and above the inductor box.

[0011] Preferably, the energy storage inductor in the AC-AC power conversion circuit is sealed inside an inductor box, and the heat dissipation surface of the inductor box is placed in an air duct to dissipate the heat generated by the energy storage inductor separately.

[0012] Preferably, the cooling fan is located above the casing and protected by a top cover. Both the cooling fan and the auxiliary cooling fan are connected to a voltage regulation and control circuit, which controls their operation based on the temperature signal collected by the temperature sensor.

[0013] Preferably, the front of the housing is provided with a handle, so that all components and panels can be installed and maintained from the front without having to flip the housing over.

[0014] The control method for a SiCMOS-based AC-AC solid-state voltage regulator includes the following steps: Step 1: The voltage sampling unit acquires the input voltage and output voltage signals in real time; Step 2: The mode determination unit determines the current operating mode based on the input voltage signal. When the input voltage is higher than the voltage setting value (220V), it enters buck mode; When the input voltage is lower than the voltage setting value (220V), it enters boost mode; When the input voltage is within the preset deviation range of the voltage setting value, it enters bypass mode; Step 3: The switch driver unit drives the corresponding SiCMOS transistor to turn on or off according to the mode judgment result; Step 4: The voltage regulation and control circuit compares the output voltage with the reference voltage, generates a PWM control signal, and adjusts the duty cycle of the SiCMOS transistor through the switching drive unit to achieve precise regulation of the output voltage; Step 5: The temperature sensor collects the temperature signals of each key component in real time, and the voltage regulation and control circuit controls the operation of the cooling fan and auxiliary cooling fan according to the temperature signals.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention uses SiCMOS power devices to construct an AC-AC power conversion circuit, which has advantages such as fast switching speed, low on-resistance, and low switching loss compared to traditional thyristor devices. It can achieve millisecond-level voltage response output and higher regulation accuracy.

[0016] This invention adopts a bidirectional Buck-Boost topology and, in conjunction with a working mode switching circuit, can automatically switch between buck, boost, and bypass operation modes according to the input voltage range. It has a wide voltage regulation range and can adapt to various complex power grid environments.

[0017] This invention employs a unique layered heat dissipation structure, placing the components requiring heat dissipation within an IP54-rated air duct and the circuit board within an IP65-rated enclosed enclosure. This effectively separates the heat sources, ensuring that air only passes through the air duct, avoiding contact with the circuit board and working components, and preventing moisture and dust from entering. This provides better protection for critical components and the circuit board.

[0018] This invention optimizes the heat dissipation layout. The MOSFET is placed above the inductor box to prevent heated air from affecting the inductor's heat dissipation. The power inductor is sealed inside the inductor box, which increases the heat dissipation area and significantly reduces the temperature rise. The heat dissipation surface of the inductor box is placed in the air duct, which is conducive to the separate dissipation of its heat.

[0019] This invention employs an intelligent fan control system, in which multiple parallel fans are installed in the air duct. The operation of the fans is controlled according to the temperature, ensuring heat dissipation while saving energy. An auxiliary cooling fan is installed inside the circuit board box to increase air convection around the circuit board and enhance the heat dissipation effect.

[0020] All components and boards in this invention can be installed from the front, avoiding the need to flip the housing during installation. Handles are also designed for easy installation, greatly improving the convenience of installation and maintenance. Attached Figure Description

[0021] Figure 1 This is an overall structural block diagram of the AC-AC solid-state voltage regulation device based on SiCMOS of the present invention; Figure 2 This is a circuit diagram of the AC-AC power conversion circuit of the present invention; Figure 3 This is a block diagram of the working mode switching circuit and voltage regulation control circuit of the present invention (S1-S8 are the first to eighth SiCMOS transistors, each transistor is connected in anti-parallel with a SiC Schottky diode; L is the energy storage inductor; C is the output filter capacitor). Figure 4 This is a front sectional view of the structure of the present invention; Figure 5 This is an internal front view of the present invention; Figure 6This is a longitudinal sectional view of the layered heat dissipation structure of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1-6 A SiCMOS-based AC-AC solid-state voltage regulator includes an AC-AC power conversion circuit, a working mode switching circuit, and a voltage regulation control circuit. The AC-AC power conversion circuit consists of SiCMOS power devices, inductor L, and capacitor C, and is used to achieve efficient energy transfer. The input terminal of the operating mode switching circuit is connected to the control terminal of the AC-AC power conversion circuit, and is used to switch the input voltage buck, boost and bypass operation modes according to the input voltage range. The output terminal of the voltage regulation control circuit is connected to the control terminals of the AC-AC power conversion circuit and the working mode switching circuit, respectively, to achieve a fast and accurate response to the input voltage according to the output voltage requirements.

[0024] The AC-AC power conversion circuit adopts a bidirectional Buck-Boost topology, including a first SiCMOS transistor, a second SiCMOS transistor, a third SiCMOS transistor, a fourth SiCMOS transistor, a fifth SiCMOS transistor, a sixth SiCMOS transistor, a seventh SiCMOS transistor, an eighth SiCMOS transistor, an energy storage inductor, and an output filter capacitor. The first and second SiCMOS transistors are connected in reverse series to form a first bidirectional switch, one end of which is connected to the live wire of the input AC power supply; the third and fourth SiCMOS transistors are connected in reverse series to form a second bidirectional switch, one end of which is connected to the neutral wire of the input AC power supply; an energy storage inductor is connected between the common terminal of the first and second bidirectional switches; the fifth and sixth SiCMOS transistors are connected in reverse series to form a third bidirectional switch, one end of which is connected to the other end of the first bidirectional switch, and the other end is connected to the live wire of the output terminal; an output filter capacitor is connected between the live wire and the neutral wire of the output terminal; the other end of the first bidirectional switch is also connected to the neutral wire of the output terminal through a seventh SiCMOS transistor, and the other end of the second bidirectional switch is also connected to the live wire of the output terminal through an eighth SiCMOS transistor.

[0025] The operating mode switching circuit includes a voltage sampling unit, a mode judgment unit, and a switch driving unit. The input terminal of the voltage sampling unit is connected to the input AC power supply and the output terminal, respectively, for acquiring input voltage and output voltage signals. The input terminal of the mode judgment unit is connected to the output terminal of the voltage sampling unit, for determining the current operating mode based on the acquired voltage signals. The input terminal of the switch driving unit is connected to the output terminal of the mode judgment unit, and the output terminal is connected to the gate of all SiCMOS transistors, for driving the corresponding SiCMOS transistors to turn on or off according to the mode judgment result.

[0026] The voltage regulation control circuit includes an error amplifier, a PWM modulator, and a drive isolation unit. The input of the error amplifier is connected to a reference voltage and the output voltage feedback signal from the voltage sampling unit, respectively, and is used to compare the output voltage with the reference voltage and generate an error signal. The input of the PWM modulator is connected to the output of the error amplifier and is used to generate a PWM control signal with a corresponding duty cycle based on the error signal. The input of the drive isolation unit is connected to the output of the PWM modulator, and the output is connected to the control terminal of the switch drive unit, and is used to isolate and amplify the PWM control signal.

[0027] The SiCMOS-based AC-AC solid-state voltage regulator also includes a layered heat dissipation structure, which includes: a housing, the interior of which is divided into an air duct and a closed enclosure by a partition; the air duct has an IP54 protection rating and is provided with an air inlet and an air outlet, and multiple parallel cooling fans are installed inside the air duct; the closed enclosure has an IP65 protection rating and is used to install circuit board assemblies, and auxiliary cooling fans are installed inside the closed enclosure.

[0028] In the AC-AC power conversion circuit, the SiCMOS power devices are mounted on the MOSFET heat sink. The MOSFET heat sink is connected to the SiCMOS power devices through an alumina ceramic sheet. The MOSFET heat sink is located inside the air duct and above the inductor box, which can prevent heated air from affecting the inductor heat dissipation.

[0029] In the AC-AC power conversion circuit, the energy storage inductor is sealed inside an inductor box made of aluminum alloy with heat dissipation fins covering its surface, significantly increasing the heat dissipation area. The heat dissipation surface of the inductor box is positioned within an airflow channel, facilitating the individual dissipation of heat generated by the energy storage inductor. The energy storage inductor uses an iron-silicon-aluminum magnetic core and Litz wire winding, offering advantages such as low high-frequency loss and good DC bias characteristics.

[0030] The cooling fan is located on top of the casing and protected by a top cover. Both the cooling fan and the auxiliary cooling fan are connected to a voltage regulation and control circuit, which controls their operation based on the temperature signal collected by the temperature sensor.

[0031] The front of the casing features two handles, allowing for easy installation and maintenance of all components and panels without the need to flip the casing over. The casing is made of cold-rolled steel sheet with an electrostatic powder coating, providing excellent corrosion resistance.

[0032] The working principle of the SiCMOS-based AC-AC solid-state voltage regulation device of this invention is as follows: When the device is powered on, the voltage sampling unit collects the input voltage and output voltage signals in real time and sends the collected signals to the mode judgment unit and the voltage regulation control circuit.

[0033] The mode determination unit determines the current operating mode based on the input voltage signal: When the input voltage exceeds the standard voltage limit (235V), the voltage is switched to buck mode. At this time, the switching driver unit turns off the seventh and eighth SiCMOS transistors, and drives the first to sixth SiCMOS transistors to operate according to the Buck mode control logic. The voltage regulation control circuit adjusts the duty cycle of the PWM control signal based on the output voltage feedback signal to stabilize the output voltage at the rated value (e.g., 220V).

[0034] When the input voltage is lower than the standard lower voltage limit (198V), the system enters boost mode. At this time, the switching driver unit turns off the seventh and eighth SiCMOS transistors, and drives the first to sixth SiCMOS transistors to operate according to the Boost mode control logic. The voltage regulation control circuit adjusts the duty cycle of the PWM control signal based on the output voltage feedback signal to stabilize the output voltage at the rated value.

[0035] When the input voltage is within the standard voltage range (198V~235V), it enters bypass mode. At this time, the switch driver unit drives the first to sixth SiCMOS transistors to turn off, and drives the seventh and eighth SiCMOS transistors to turn on. The input voltage is directly supplied to the load through the bypass switch, and the device loss is minimized.

[0036] During device operation, temperature sensors collect real-time temperature signals from the MOSFET heatsink, inductor housing, and enclosed enclosure, and send these signals to the voltage regulation and control circuit. The voltage regulation and control circuit then controls the operation of the cooling fan and auxiliary cooling fan based on the temperature signals. When the temperature of the MOSFET heatsink is below 50°C, both cooling fans stop operating. When the temperature of the MOSFET heatsink is between 50°C and 70°C, one cooling fan operates. When the temperature of the MOSFET heatsink exceeds 70°C, both cooling fans will operate. When the temperature inside the sealed enclosure exceeds 40°C, the auxiliary cooling fan will operate.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A SiCMOS-based AC-AC solid-state voltage regulator, characterized in that, Includes AC-AC power conversion circuit, operating mode switching circuit and voltage regulation and control circuit; The AC-AC power conversion circuit consists of SiCMOS power devices, inductor L, and capacitor C, and is used to achieve efficient energy transfer. The input terminal of the operating mode switching circuit is connected to the control terminal of the AC-AC power conversion circuit, and is used to switch the input voltage buck, boost and bypass operation modes according to the input voltage range. The output terminal of the voltage regulation control circuit is connected to the control terminals of the AC-AC power conversion circuit and the working mode switching circuit, respectively, to achieve a fast and accurate response to the input voltage according to the output voltage requirements.

2. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 1, characterized in that, The AC-AC power conversion circuit adopts a bidirectional Buck-Boost topology, including: The first SiCMOS transistor and the second SiCMOS transistor are connected in reverse series to form the first bidirectional switch, one end of which is connected to the live wire of the input AC power supply. The third SiCMOS transistor and the fourth SiCMOS transistor are connected in reverse series to form a second bidirectional switch, one end of which is connected to the neutral terminal of the input AC power supply. The energy storage inductor is connected between the common terminal of the first and second bidirectional switches; The fifth SiCMOS transistor and the sixth SiCMOS transistor are connected in reverse series to form a third bidirectional switch. One end of the switch is connected to the other end of the first bidirectional switch, and the other end is connected to the live wire of the output terminal. The output filter capacitor is connected between the live wire and the neutral wire at the output terminal. The other end of the first bidirectional switch is also connected to the neutral terminal of the output terminal through a seventh SiCMOS transistor, and the other end of the second bidirectional switch is also connected to the live terminal of the output terminal through an eighth SiCMOS transistor.

3. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 2, characterized in that, The working mode switching circuit includes a voltage sampling unit, a mode judgment unit, and a switch driving unit; The input terminal of the voltage sampling unit is connected to the input AC power supply and the output terminal respectively, and is used to collect the input voltage and output voltage signals. The input terminal of the mode determination unit is connected to the output terminal of the voltage sampling unit, and is used to determine the current working mode based on the collected voltage signal. The input terminal of the switch driving unit is connected to the output terminal of the mode judgment unit, and the output terminal is connected to the gate of each of the SiCMOS transistors, which is used to drive the corresponding SiCMOS transistors to turn on or off according to the mode judgment result.

4. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 3, characterized in that, The voltage regulation control circuit includes an error amplifier, a PWM modulator, and a drive isolation unit; The input terminals of the error amplifier are respectively connected to the reference voltage and the output voltage feedback signal output by the voltage sampling unit, which are used to compare the output voltage with the reference voltage and generate an error signal; The input terminal of the PWM modulator is connected to the output terminal of the error amplifier, and is used to generate a PWM control signal with a corresponding duty cycle according to the error signal; The input terminal of the drive isolation unit is connected to the output terminal of the PWM modulator, and the output terminal is connected to the control terminal of the switch drive unit, which is used to isolate and amplify the PWM control signal.

5. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 1, characterized in that, It also includes a layered heat dissipation structure, which comprises: The casing is internally divided into air ducts and a sealed enclosure by partitions. The air duct has an IP54 protection rating and is equipped with an air inlet and an air outlet. Multiple parallel cooling fans are installed inside the air duct. The enclosed enclosure has an IP65 protection rating and is used to install circuit board assemblies. An auxiliary cooling fan is installed inside the enclosed enclosure.

6. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 5, characterized in that, In the AC-AC power conversion circuit, the SiCMOS power devices are mounted on MOSFET heat sinks. The MOSFET heat sinks are connected to the SiCMOS power devices via alumina ceramic sheets. The MOSFET heat sinks are located inside the air duct and above the inductor box.

7. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 6, characterized in that, The energy storage inductor in the AC-AC power conversion circuit is sealed inside an inductor box, and the heat dissipation surface of the inductor box is placed in an air duct to dissipate the heat generated by the energy storage inductor separately.

8. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 5, characterized in that, The cooling fan is located on top of the casing and protected by a top cover. Both the cooling fan and the auxiliary cooling fan are connected to a voltage regulation and control circuit, which controls their operation based on the temperature signal collected by the temperature sensor.

9. The SiCMOS-based AC-AC solid-state voltage regulation device according to claim 5, characterized in that, The front of the housing is equipped with a handle, allowing all components and panels to be installed and maintained from the front without having to flip the housing over.

10. The control method for the SiCMOS-based AC-AC solid-state voltage regulating device according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: The voltage sampling unit acquires the input voltage and output voltage signals in real time; Step 2: The mode determination unit determines the current operating mode based on the input voltage signal. When the input voltage is higher than the voltage setting value (220V), it enters buck mode; When the input voltage is lower than the voltage setting value (220V), it enters boost mode; When the input voltage is within the preset deviation range of the voltage setting value, it enters bypass mode; Step 3: The switch driver unit drives the corresponding SiCMOS transistor to turn on or off according to the mode judgment result; Step 4: The voltage regulation and control circuit compares the output voltage with the reference voltage, generates a PWM control signal, and adjusts the duty cycle of the SiCMOS transistor through the switching drive unit to achieve precise regulation of the output voltage; Step 5: The temperature sensor collects the temperature signals of each key component in real time, and the voltage regulation and control circuit controls the operation of the cooling fan and auxiliary cooling fan according to the temperature signals.

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