Silicon carbide inverter and control method thereof

Abstract

The invention discloses a silicon carbide inverter and a control method thereof. The silicon carbide inverter mainly comprises a three-phase power frequency alternating current power supply input connection point, a three-phase rectifier filter of an integrated buffer circuit, two groups of silicon carbide MOSFET modules and driving circuits thereof, a programmable driving interconnection control module, an embedded controller and six independent output connection points. Wherein the silicon carbide MOSFET modules are divided into two groups, and each group is provided with six silicon carbide MOSFETs and corresponding driving circuits. The programmable drive interconnection control module can select working modes according to different enable signals, single-phase or three-phase alternating current inversion is achieved, and the high frequency of the silicon carbide MOSFET is calculated, optimized and controlled by combining the working temperature factor of the silicon carbide MOSFET. The embedded controller controls single-phase or three-phase alternating-current inversion of the silicon carbide MOSFET module, and monitoring and feedback closed-loop control can be carried out on operating parameters of the high-voltage power supply. The silicon carbide inverter realizes multi-mode selection control and intelligent safety efficiency control.

Description

Technical Field

[0001] The present invention relates to the conversion of direct current or alternating current input power to surge output power and their control or regulation, and in particular to a silicon carbide inverter and a control method thereof. Background Art

[0002] High voltage power supply is a special power supply equipment and is widely used in the field of environmental protection, such as pollution control in industries such as steel, cement, coal-fired power generation, sewage treatment, and odor control.

[0003] According to the standard classification of the environmental protection industry, the commonly used high-voltage power supply types include single-phase thyristor voltage-regulated high-voltage power supply, three-phase thyristor voltage-regulated high-voltage power supply, high-frequency high-voltage power supply, variable-frequency high-voltage power supply, etc. High-voltage power supply distribution is generally a three-phase industrial frequency AC power supply, which is mainly divided into a regulation control part and a high-voltage boost rectification part.

[0004] The control part of the single-phase thyristor voltage-regulated high-voltage power supply and the three-phase thyristor voltage-regulated high-voltage power supply directly modulates the industrial frequency AC power supply, and the operating frequency is the grid frequency 50 / 60HZ. When the control angle (trigger angle) of the thyristor increases, its power factor will decrease. There is a non-conduction working time in the grid AC half-wave cycle. The power provided by the grid is not fully utilized, resulting in a very low power factor. Harmonic components will be generated during the thyristor voltage regulation process, and some harmonic frequencies are the same as the grid frequency. These harmonic components will not only reduce the power supply efficiency, but also cause harmonic pollution to the grid, affecting the normal operation of other equipment. At the same time, the thyristor is a semi-controlled device, which is uncontrollable after conduction, and the operating frequency is the grid frequency. The dynamic response speed is slow and the adaptability to working conditions is poor. However, due to the simple and low cost of the thyristor voltage regulation circuit, the market share is still large.

[0005] The control part of the high-frequency high-voltage power supply is a high-frequency inverter circuit, which rectifies the three-phase industrial frequency AC power supply into DC, and then inverts it into high-frequency AC through the silicon semiconductor IGBT module. When the current is large, the switching loss of the silicon semiconductor IGBT module is high, and there is a large reverse recovery current. In order to limit the switching loss and ensure the reliable operation of the inverter, the operating frequency of the silicon semiconductor IGBT module of the high-frequency high-voltage power inverter generally does not exceed 20 kilohertz. The high switching loss of the silicon semiconductor IGBT module restricts the improvement of the efficiency of the high-voltage power supply, and the limitation of the operating frequency restricts the miniaturization of the high-voltage power supply. The volume of the high-frequency transformer in the high-frequency boost circuit is related to the operating frequency of the inverter. The higher the frequency, the smaller the volume.

[0006] In recent years, with the development of electric vehicles and new energy industries, the third-generation silicon carbide semiconductor technology has begun to be mass-produced and applied in batches. Silicon carbide MOSFET has a highly stable crystal structure and a high energy band width. Its operating frequency is much higher than that of silicon semiconductor IGBT modules. It also has excellent high-temperature working characteristics and low switching losses. It is very suitable for high-voltage power supplies. The existing technologies in this regard include the following technical solutions.

[0007] Chinese invention patent CN108023493A discloses a device for reducing the common-mode voltage amplitude of a silicon carbide inverter, and discloses that the device includes a current ripple minimum common-mode voltage reduction PWM, a drive circuit, a three-phase silicon carbide inverter module and a load. The current ripple minimum common-mode voltage reduction PWM is completed by a digital processing circuit to calculate the three-phase duty cycle under the current ripple loss minimum target in real time and generate a corresponding three-phase switch sequence; the digital processing circuit includes a power supply circuit, a digital operation chip, a sampling circuit, an input and output port and a peripheral circuit; the drive circuit generates a corresponding drive signal of the silicon carbide device according to the switch sequence signal output by the current ripple minimum common-mode voltage reduction PWM; the three-phase silicon carbide inverter module controls the opening and closing of the silicon carbide device according to the drive signal issued by the drive circuit, and the load is connected to the three-phase silicon carbide inverter module.

[0008] China's invention patent CN112104246A discloses a low harmonic control system and method for a three-level high switching frequency silicon carbide inverter, which discloses a low harmonic control system including an amplitude adjustment module, a selection module, a modulation wave superposition module, an amplitude limiting module, and a drive signal generation module. The amplitude adjustment module adjusts the amplitude of the original modulation wave; the selection switch of the selection module determines the size of the original modulation wave and outputs different amplitude adjustment amounts; the modulation wave adjustment module performs a superposition operation on the modulation wave after amplitude adjustment; the amplitude limiting module performs amplitude limitation on the modulation wave obtained by each superposition; and the drive signal generation module is used to drive the silicon carbide power switch device in the main circuit. The main circuit of the three-level high switching frequency silicon carbide inverter contains two left and right bridge arms, and an isolation inductor is used to eliminate the mutual influence between the left and right bridge arms. The present invention can effectively avoid the dead zone effect and reduce the output current harmonics of the three-level high switching frequency silicon carbide inverter.

[0009] Chinese invention patent CN110932587A is a high-efficiency, low-harmonic control method for high-switching-frequency silicon carbide inverters. It discloses that after the fundamental wave of the output current of the high-switching-frequency silicon carbide inverter is extracted by the fundamental wave current extraction module, the accurate current interval is obtained as the basis for judging the current interval, and the influence of the high-frequency harmonics of the output current on the current interval judgment is eliminated. The high-efficiency, low-harmonic modulation module includes four submodules: current interval judgment, modulation wave amplitude adjustment, zero-sequence component calculation, and logic synthesis. In different current intervals, the purpose of compensating the dead zone effect of the high-switching-frequency silicon carbide inverter is achieved through the modulation wave amplitude adjustment submodule; the purpose of reducing the switching loss of the high-switching-frequency silicon carbide inverter is achieved through the zero-sequence component calculation submodule; and the logic synthesis module adds the dead zone output drive signal. The present invention effectively combines dead zone compensation and switching loss reduction to achieve high-efficiency, low-harmonic operation of the high-switching-frequency silicon carbide inverter.

[0010] Some of these inverters that use silicon carbide MOSFETs require rewiring, which is inconvenient for the transformation of old lines. Some high-voltage power supply performance has much room for improvement, and the high cost causes waste of resources. Summary of the invention

[0011] In view of the problems described in the background technology, the present invention proposes a new type of silicon carbide inverter and a control method thereof to improve the performance of the high-voltage power supply, reuse the original cables and high-voltage boost rectifier parts, control costs and reduce resource waste, and improve the overall performance of the old high-voltage power supply. The specific technical solutions are as follows: A silicon carbide inverter comprises a three-phase industrial frequency AC power input connection point, a three-phase rectifier filter with an integrated buffer circuit, two groups of silicon carbide MOSFET modules and drive circuits thereof, a programmable drive interconnection control module, an embedded controller, and six independent output connection points; the embedded controller comprises three drive control modes corresponding to different working scenarios: control mode one is modulated according to a single-phase SPWM mode to achieve single-phase AC inversion; control mode two is modulated according to a high-frequency resonant alternating conduction mode to also achieve single-phase AC inversion; control mode three is modulated according to a three-phase SPWM mode to achieve three-phase AC inversion.

[0012] The programmable drive interconnection control module combines the operating temperature factor of the silicon carbide MOSFET to calculate the high-frequency drive control formula of the silicon carbide MOSFET: Where: fw is the operating frequency, k is the correction coefficient, Vs is the AC output voltage, fs is the switching frequency, Ls is the harmonic suppression inductor, fL is the inductor harmonic frequency, fC is the capacitor harmonic frequency, fsw is the switching frequency, Tmax is the maximum allowable operating temperature of the silicon carbide MOSFET, and Ta is the actual operating temperature of the silicon carbide MOSFET.

[0013] The two groups of silicon carbide MOSFET modules each include 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules correspond to 6 driving circuits respectively.

[0014] The programmable drive interconnection control module includes 12 PWM outputs, 6 PWM drive signal inputs, and 2 enable signal inputs. The 12 PWM outputs are connected to 12 drive circuits of two groups of silicon carbide MOSFET modules, and the 6 PWM drive signal inputs and 2 enable signal inputs are connected to the 6 PWM drive signal outputs and 2 enable signals of the embedded controller; a microcontroller MCU is configured, and a field programmable gate array FPGA is used to realize high-speed calculation and execution of a drive control strategy, and a load current is quickly sampled and a PID controller is used for real-time adjustment to realize a dynamic load tracking function, so as to improve the dynamic response speed and stability of the inverter by intelligent drive control; an automatic adaptive dead time control algorithm is realized by the microcontroller MCU, and the width of the dead time is adjusted in real time according to the change of the load. The calculation formula of the dead time is: Td=(√2*π) / (3*Vs*Ls*(fs^2-fpwm^2)), wherein: Td is the dead time, Vs is the source voltage, Ls is the source inductance, fs is the corresponding switching frequency, and fpwm is the pulse width modulation frequency.

[0015] When the two enable signal inputs are at a low level or a high level, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules.

[0016] The two enable signal inputs select the working mode. When the first enable signal is enabled, the two PWM drive signal inputs control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules realize single-phase AC inversion.

[0017] The two enable signal inputs select the working mode. When the second enable signal is enabled, the six PWM drive signal inputs control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules realize three-phase AC inversion.

[0018] The six independent output connection points are changed according to the two-way enable signal input of the programmable drive interconnection control module. When the first enable signal is enabled, the six independent output connection points are divided into two single-phase AC output connection points, and three output connection points with the same electrical performance form the same output, realizing single-phase AC output and connecting to the outside; when the second enable signal is enabled, the six independent output connection points are divided into three three-phase AC output connection points, and two output connection points with the same electrical performance form the same output, realizing three-phase AC output and connecting to the outside.

[0019] The embedded controller includes 6 PWM drive signal outputs and 2 enable signal outputs. The drive connection circuit inside the programmable drive interconnection control module is selected through the 2 enable signal outputs. When the 2 enable signal outputs are simultaneously at a low level or simultaneously at a high level, the programmable drive interconnection control module prohibits driving and controlling two groups of silicon carbide MOSFET modules.

[0020] The embedded controller is based on a digital signal processor or a single-chip microcomputer. In addition to 6-way PWM drive signal output and 2-way enable signal output, it also includes multiple analog inputs, multiple digital switch inputs, multiple digital switch outputs, and multiple communication ports to realize the monitoring of high-voltage power supply operating parameters such as input voltage, input current, output voltage, output current, operating temperature, etc., as well as feedback closed-loop control. Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] 1. A silicon carbide inverter and its control method, which use the same inverter hardware circuit to realize three control mode methods. Without changing the hardware circuit and structure of the silicon carbide inverter, single-phase AC inverter, three-phase AC inverter and high-frequency inverter can be realized. It is applied to new high-voltage power supplies to improve the overall performance of the power supply. The temperature factor of silicon carbide MOSFET working and the high-frequency drive control algorithm of silicon carbide MOSFET are combined to greatly improve the safety.

[0022] 2. A silicon carbide inverter and its control method, with silicon carbide MOSFET module as the core, can utilize the connection cables and single- and three-phase rectifier transformers of the original high-voltage power supply to perform frequency conversion control transformation on the single-phase and three-phase half-controlled thyristor high-voltage power supply, and utilize the original cables and high-voltage boost rectifier parts, control costs and reduce resource waste, improve the overall performance of the old high-voltage power supply, greatly improve power supply efficiency, reduce grid harmonic interference, improve working condition adaptability, and have low transformation cost.

[0023] 3. A silicon carbide inverter and its control method, with silicon carbide MOSFET module as the core, small switching loss and high operating frequency. It can reuse the connection cables and high-frequency and variable-frequency rectifier transformers of the original high-voltage power supply to achieve the upgrade and transformation of silicon IGBT-controlled high-frequency and variable-frequency high-voltage power supply, reduce switching loss and improve power supply efficiency.

[0024] 4. A silicon carbide inverter and a control method thereof. Using the same power level silicon carbide inverter, different types of high-voltage power supplies of the same power level can be applied, which is conducive to achieving standardized production and reducing product and material inventory.

[0025] 5. A silicon carbide inverter and its control method use a multifunctional programmable drive interconnection control module, which includes 12 PWM outputs, 6 PWM drive signal inputs and 2 enable signal inputs, and can realize complex connection and control with the drive circuit and embedded controller of the silicon carbide MOSFET module. Different working modes can be selected through the 2-way enable signal input to realize single-phase AC inverter and three-phase AC inverter, which has high flexibility and adaptability.

[0026] 6. A silicon carbide inverter and a control method thereof. The six independent output connection points of the silicon carbide inverter can be changed according to the enable signal input of the programmable drive interconnection control module: when the first enable signal is enabled, it can be divided into two output connection points of single-phase AC, and three output connection points with the same electrical performance form the same output to achieve single-phase AC output and connection with the outside; when the second enable signal is enabled, it can be divided into three output connection points of three-phase AC, and two output connection points with the same electrical performance form the same output to achieve three-phase AC output and connection with the outside. This flexible output connection method is difficult to achieve using the existing technology.

[0027] 7. A silicon carbide inverter and its control method, the embedded controller includes three drive control modes, corresponding to different working scenarios: control mode 1 is modulated according to the single-phase SPWM mode to achieve single-phase AC inverter; control mode 2 is modulated according to the high-frequency resonant alternating conduction mode to achieve single-phase AC inverter; control mode 3 is modulated according to the three-phase SPWM mode to achieve three-phase AC inverter. Different modes provide users with more choices, which can be switched according to specific circumstances. This diversified drive control mode provides users with more choices to meet different application requirements.

[0028] 8. A silicon carbide inverter and its control method, with a digital signal processor or a single-chip microcomputer as the core, in addition to conventional PWM drive signal output and enable signal output, also includes multiple analog inputs, multiple digital switch inputs, multiple digital switch outputs and multiple communication ports. This enables the embedded controller to achieve comprehensive monitoring and feedback closed-loop control of high-voltage power supply operating parameters, facilitates upgrading and transformation of other types of high-voltage power supplies, and overcomes the defects of the embedded controller in the prior art that may be relatively weak in functional integration and scalability.

[0029] 9. A silicon carbide inverter and its control method, which monitors operating parameters and performs feedback closed-loop control through an embedded controller, and has precise output. The embedded controller can monitor input voltage, input current, output voltage, output current, operating temperature and other parameters in real time, and accurately adjust the output through feedback closed-loop control to ensure that the AC power output by the inverter is stable and reliable, meeting the needs of various high-precision equipment.

[0030] 10. A silicon carbide inverter and its control method, the integration of the buffer circuit effectively reduces the voltage spike in the circuit and reduces the risk of damage to electronic components. At the same time, it also reduces electromagnetic interference, improves the stability and reliability of the system, and reduces the impact on surrounding electronic equipment.

[0031] 11. A silicon carbide inverter and a control method thereof. The characteristics of silicon carbide materials make the inverter suitable for high dynamic performance occasions. The fast switching characteristics of silicon carbide enable the inverter to respond to changes in the input signal in a short time and output stable alternating current. This is of great significance for some occasions with high requirements for dynamic performance, such as electric vehicles, industrial automation and other fields; the high thermal conductivity of silicon carbide materials helps to improve the heat dissipation performance of the inverter and extend the life of the equipment; silicon carbide materials with high thermal conductivity can quickly dissipate the heat generated during the operation of the inverter and reduce the temperature of the equipment. This not only improves the reliability and stability of the equipment, but also extends the service life of the equipment and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The invention discloses a circuit schematic diagram of a silicon carbide inverter and a control method thereof.

[0033] Figure 2 The present invention is a schematic diagram of a programmable drive interconnection control module of a silicon carbide inverter and a control method thereof.

[0034] Figure 3 The invention discloses a control mode and a driving waveform diagram of a silicon carbide inverter and a control method thereof.

[0035] Figure 4 The present invention discloses a control mode 2 driving waveform diagram of a silicon carbide inverter and a control method thereof.

[0036] Figure 5 The invention discloses a control mode three-drive waveform diagram of a silicon carbide inverter and a control method thereof.

[0037] Figure 6 The invention discloses a charging control waveform diagram of a three-phase rectifier filter of an integrated buffer circuit of a silicon carbide inverter and a control method thereof.

[0038] Figure 7 The invention discloses an embedded controller for a silicon carbide inverter and a control method thereof.

[0039] Figure 8 The invention discloses a silicon carbide inverter and a control method thereof, wherein the control mode is one, and the schematic diagram of the transformation scheme of the single-phase thyristor regulation control circuit in a high-voltage power supply is replaced. In the diagram, the single-phase step-up rectifier transformer can be reused.

[0040] Fig. 9The present invention is a control mode 2 of a silicon carbide inverter and its control method, which is a schematic diagram of a modification scheme for replacing an IGBT control circuit in a high-voltage power supply. In the figure, a high-frequency step-up rectifier transformer can be reused.

[0041] Fig.10 The present invention is a control mode 2 of a silicon carbide inverter and its control method, which is a schematic diagram of a transformation scheme for replacing a three-phase thyristor regulation control circuit in a high-voltage power supply. In the diagram, the three-phase step-up rectifier transformer can be reused.

[0042] In the attached figure: M1 and M2 are silicon carbide MOSFET modules; Time (ms) is the horizontal axis unit in milliseconds; A11, A12, A13, B11, B12, B13 are silicon carbide inverter output connection points. When single-phase AC inverter is used, A11, A12, A13 output at one end, and B11, B12, B13 output at the other end. When three-phase AC inverter is used, A11 and B11 are A-phase outputs, A12 and B12 are B-phase outputs, and A13 and B13 are C-phase outputs; QD1 is a programmable drive interconnection control module; PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 are embedded controller PWM drive signal outputs; TP is the enable signal output of the programmable drive interconnection control module and the embedded controller; SP It is the enable signal output of the programmable drive interconnection control module and the embedded controller; AI1, AI2, AI3, AI4, AI5, AI6, AI7, and AI8 are multi-channel analog inputs of the embedded controller, which are used for high-voltage power supply operation parameter monitoring; DI1, DI2, DI3, DI4, DI5, and DI6 are multi-channel digital switch inputs of the embedded controller, which are used for high-voltage power supply operation parameter monitoring or other control functions; DO1, DO2, DO3, DO4, DO5, and DO6 are multi-channel digital switch outputs of the embedded controller, which are used for high-voltage power supply control or other output functions; VSAN is a triangular carrier; COM1 and COM2 are multiple communication ports of the embedded controller, which are used for high-voltage power supply communication control and other types of high-voltage voltage upgrades and modifications. DETAILED DESCRIPTION

[0043] A silicon carbide inverter and a control method thereof are powered by a three-phase industrial frequency AC power supply, and mainly include a three-phase industrial frequency AC power supply input connection point, a three-phase rectifier filter with an integrated buffer circuit, two groups of silicon carbide MOSFET modules and drive circuits thereof, a programmable drive interconnection control module, an embedded controller, and 6 independent output connection points; the programmable drive interconnection control module calculates a high-frequency drive control formula of the silicon carbide MOSFET in combination with the operating temperature factor of the silicon carbide MOSFET: fw is the operating frequency, k is the correction coefficient, Vs is the AC output voltage, fs is the switching frequency, Ls is the harmonic suppression inductor, fL is the inductor harmonic frequency, fC is the capacitor harmonic frequency, fsw is the switching frequency, Tmax is the maximum allowable operating temperature of the silicon carbide MOSFET, and Ta represents the actual operating temperature of the silicon carbide MOSFET.

[0044] When the heat dissipation conditions are poor, the operating frequency of the silicon carbide MOSFET generally needs to be reduced. This is because when working at high frequencies, the silicon carbide MOSFET will generate more heat, so the temperature factor is set, the temperature factor Tmax / Ta, to dynamically adjust the operating frequency. When Ta is close to Tmax, the ratio of Tmax / Ta is close to 1, and the operating frequency remains high; when Ta is significantly lower than Tmax, the ratio is greater than 1, and the operating frequency will be appropriately increased; conversely, when Ta exceeds Tmax, the ratio is less than 1, and the operating frequency will be significantly reduced to reduce heat generation and protect the MOSFET. In practical applications, Ta is monitored in real time through a temperature sensor, and fw is dynamically adjusted according to the formula to ensure that the MOSFET operates within a safe operating temperature range.

[0045] Two groups of silicon carbide MOSFET modules and their driving circuits: Two groups of silicon carbide MOSFET modules, each group includes 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules correspond to 6 driving circuits respectively.

[0046] Programmable drive interconnection control module: The programmable drive interconnection control module includes 12 PWM outputs, 6 PWM drive signal inputs, and 2 enable signal inputs. The 12 PWM outputs of the programmable drive interconnection control module are connected to the 12 drive circuits of two groups of silicon carbide MOSFET modules. The 6 PWM drive signal inputs and 2 enable signal inputs of the programmable drive interconnection control module are connected to the 6 PWM drive signal outputs and 2 enable signals of the embedded controller. When the 2 enable signal inputs are at a low level or a high level, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules. The programmable drive interconnection control module selects the working mode through the 2 enable signal inputs. When the first enable signal is enabled, the 2 PWM drive signal inputs control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules can achieve single-phase AC inverter. When the second enable signal is enabled, 6 PWM drive signal inputs control 12 PWM outputs, so that 12 silicon carbide MOSFET modules realize three-phase AC inverter; configure the microcontroller MCU, field programmable gate array FPGA to realize high-speed calculation and execution of drive control strategy, quickly sample the load current and use the PID (proportional-integral-differential) controller for real-time adjustment to realize dynamic load tracking function, and improve the dynamic response speed and stability of the inverter by intelligent drive control; realize the automatic adaptation of dead time control algorithm through the microcontroller MCU, and adjust the width of the dead time in real time according to the change of load to ensure the stable operation and high efficiency of the inverter under different loads. The calculation formula of dead time is: Td=(√2*π) / (3*Vs*Ls*(fs^2-fpwm^2)), where: Td is dead time, Vs is source voltage, Ls is source inductance, fs is corresponding switching frequency, and fpwm is pulse width modulation frequency.

[0047] 6 independent output connection points of silicon carbide inverter: The 6 independent output connection points of silicon carbide inverter change according to the 2-way enable signal input of programmable drive interconnection control module. When the first enable signal is enabled, the 6 independent output connection points are divided into two output connection points of single-phase AC, and 3 output connection points with the same electrical performance form the same output, realizing single-phase AC output and connecting to the outside. When the second enable signal is enabled, the 6 independent output connection points are divided into three output connection points of three-phase AC, and 2 output connection points with the same electrical performance form the same output, realizing three-phase AC output and connecting to the outside.

[0048] Embedded controller: The embedded controller includes 6 PWM drive signal outputs and 2 enable signal outputs. The drive connection circuit inside the programmable drive interconnection control module is selected through the 2 enable signal outputs. When the 2 enable signal outputs are both low or high, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules. The embedded controller includes three drive control modes. In control mode 1, the 2 PWM drive signal outputs of the embedded controller are modulated according to the single-phase SPWM mode, and the first enable signal of the programmable drive interconnection control module is controlled to enable, and the working mode selection of the programmable drive interconnection control module is completed. The 2 PWM drive signal outputs modulated by the single-phase SPWM control 12 silicon carbide MOSFET modules to achieve single-phase AC inverter. In control mode 2, the 2 PWM drive signal outputs of the embedded controller are modulated according to the high-frequency resonance alternating conduction mode, and the first enable signal of the programmable drive interconnection control module is controlled to enable, and the working mode selection of the programmable drive interconnection control module is completed. The 2 PWM drive signal outputs modulated by the high-frequency resonance alternating conduction mode control 12 silicon carbide MOSFET modules to achieve single-phase AC inverter. Control mode three, the embedded controller's 6-channel PWM drive signal output is modulated according to the three-phase SPWM mode, and the second enable signal of the programmable drive interconnection control module is controlled to enable, completing the working mode selection of the programmable drive interconnection control module, and the 6-channel SPWM drive signal output modulated by the three-phase SPWM controls 12 silicon carbide MOSFET modules to realize three-phase AC inverter.

[0049] Embedded controller: The embedded controller is based on a digital signal processor or a single-chip microcomputer. In addition to 6-channel PWM drive signal outputs and 2-channel enable signal outputs, it also includes multiple analog inputs, multiple digital switch inputs, multiple digital switch outputs, and multiple communication ports to monitor the high-voltage power supply operating parameters such as input voltage, input current, output voltage, output current, operating temperature, etc., as well as feedback closed-loop control, making it easy to upgrade and transform other types of high-voltage power supplies.

[0050] A specific embodiment of a silicon carbide inverter and a control method thereof: A circuit schematic diagram of a silicon carbide inverter and a control method thereof is shown in FIG. Figure 1 shown.

[0051] It is powered by a three-phase industrial frequency AC power supply, and mainly includes a three-phase industrial frequency AC power input connection point, a three-phase rectifier filter with an integrated buffer circuit, two groups of silicon carbide MOSFET modules and their drive circuits, a programmable drive interconnection control module, an embedded controller, and 6 independent output connection points.

[0052] The three-phase industrial frequency AC power supply is connected to the three-phase industrial frequency AC power supply input connection points A, B, and C.

[0053] The three-phase rectifier filter with integrated buffer circuit mainly converts the three-phase industrial frequency AC power supply into a DC power supply to supply power for the silicon carbide inverter circuit. At the same time, the integrated buffer circuit can pre-fill the filter capacitor of the three-phase rectifier filter before the pulse power supply works, so as to reduce the large current impact on the three-phase industrial frequency power supply when the capacitor is charged. In the specific circuit, the three-phase industrial frequency AC power supply is connected to the three-phase rectifier circuit composed of power diodes D1, D2, D3 and power thyristors VT1, VT2, VT3. The capacitor C1 is filtered after the industrial frequency AC is rectified and outputs a stable DC power. The control circuit of the three-phase rectifier circuit, the power thyristors VT1, VT2, VT3 are triggered by the trigger control circuit composed of relay K1, current limiting resistors Ra, Rb, Rc, and small current diodes Da, Db, Dc. The conduction and disconnection of the three-phase rectifier circuit are controlled by the conduction or disconnection of relay K1. The buffer circuit is composed of a small current diode D4, power diodes D2, D3, current limiting resistor R1, and relay K2. The conduction and disconnection of the buffer circuit are controlled by the conduction or disconnection of relay K2. Before the power supply works, the control point 2 controls the relay K2 to be energized, and the buffer circuit charges the capacitor C1. After the capacitor C1 voltage is charged high, the control point 1 controls the relay K1 to be energized to reduce the large current impact of the zero voltage charging of the capacitor C1 on the three-phase power frequency power supply. After the control relay K1 is energized, the power thyristors VT1, VT2, and VT3 are turned on after receiving the trigger signal, the power three-phase rectifier circuit works, the buffer circuit is bypassed by the power three-phase rectifier circuit, and the buffer circuit ends its work.

[0054] Three-phase rectifier filter with integrated buffer circuit, charging process see Figure 6 , control point 2 controls relay K2 to close, and the DC voltage DC1 starts to rise. After a delay of 2 to 4 seconds, the DC voltage DC1 rises to a level close to the normal working voltage. Control point 1 controls relay K1 to close, and the DC voltage DC1 rises to the normal working voltage.

[0055] Two groups of silicon carbide MOSFET modules and their driving circuits, wherein one group of silicon carbide MOSFET modules M1 is composed of silicon carbide MOSFET modules V11, V21, V31, V41, V51, and V61. Silicon carbide MOSFETs V11, V21, V31, V41, V51, and V61 are controlled by driving circuits 11, 21, 31, 41, 51, and 61, respectively. Driving circuits 11, 21, 31, 41, 51, and 61 are respectively connected to programmable drive interconnection control modules QD1. Another group of silicon carbide MOSFET modules M2 is composed of silicon carbide MOSFET modules V12, V22, V32, V42, V52, and V62. Silicon carbide MOSFETs V12, V22, V32, V42, V52, and V62 are controlled by drive circuits 12, 22, 32, 42, 52, and 62, respectively. Drive circuits 12, 22, 32, 42, 52, and 62 are respectively connected to programmable drive interconnection control modules QD1.

[0056] The programmable drive interconnection control module QD1 is designed using a programmable logic gate array CPLD or FPGA. The 12 PWM outputs 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, 62 of the programmable drive interconnection control module QD1 are connected to the 12 drive circuits of the two groups of silicon carbide MOSFET modules. The 6 PWM drive signal inputs PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 and the 2 enable signal inputs TP and SP of the programmable drive interconnection control module QD1 are connected to the 6 PWM drive signal outputs and 2 enable signals of the embedded controller. When the 2 enable signal inputs TP and SP are at low or high levels at the same time, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules. The programmable drive interconnection control module selects the working mode through two enable signal inputs TP and SP. When the first enable signal SP is enabled, the two PWM drive signal inputs PWM1 and PWM2 control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules can achieve single-phase AC inverter. When the second enable signal is enabled, the six PWM drive signal inputs PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules can achieve three-phase AC inverter.

[0057] The schematic diagram of the programmable drive interconnection control module QD1 is as follows: Figure 2 shown.

[0058] The working mode of the programmable drive interconnection control module QD1 is selected as the SP mode, the first enable signal SP enable signal is turned on, and the second enable signal TP enable signal is disabled. When the TP enable signal is disabled, the TP enable signal is at a low level, and the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 are forced to output a low level, and all drive signals connected to the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 are invalid. When the SP enable signal is turned on, the SP enable signal is high level, and the pin of the AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6 connected to the SP enable signal is high level, the other input pin of the AND gates B1, B3, B5, D2, D4, D6 is connected to the PWM1 drive signal, and the other input pin of the AND gates B2, B4, B6, D1, D3, D5 is connected to the PWM2 drive signal, and the output changes of the AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6 are the same as the changes of the PWM1 and PWM2 drive signals. The two outputs of AND gate A1 and B1 are connected to the input pin of OR gate X1, the two outputs of AND gate A2 and B2 are connected to the input pin of OR gate X2, the two outputs of AND gate A3 and B3 are connected to the input pin of OR gate X3, the two outputs of AND gate A4 and B4 are connected to the input pin of OR gate X4, the two outputs of AND gate A5 and B5 are connected to the input pin of OR gate X5, the two outputs of AND gate A6 and B6 are connected to the input pin of OR gate X6, the two outputs of AND gate C1 and D1 are connected to the input pin of OR gate Y1, the two outputs of AND gate C2 and D2 are connected to the input pin of OR gate Y2, the two outputs of AND gate C3 and D3 are connected to the input pin of OR gate Y3, the two outputs of AND gate C4 and D4 are connected to the input pin of OR gate Y4. The two outputs of AND gates C5 and D5 are connected to the input pin of OR gate Y5, and the two outputs of AND gates C6 and D6 are connected to the input pin of OR gate Y6. When the outputs of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 are low, the outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, and Y6 change, and the outputs of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, and D6 change, and the PWM drive signals connected to the pins of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, and D6 change.The outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, and Y6 are respectively connected to drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, and 62. The drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, and 62 respectively control silicon carbide MOSFET modules V11, V21, V31, V41, V51, V61, V12, V22, V32, V42, V52, and V62. That is, the PWM1 drive signal controls the silicon carbide MOSFET modules V11, V31, V51, V22, V42, and V62, and the PWM2 drive signal controls the silicon carbide MOSFET modules V21, V41, V61, V12, V32, and V52, so that the 12 silicon carbide MOSFET modules realize single-phase AC inverter.

[0059] The working mode of the programmable drive interconnection control module QD1 is selected as the SP mode, the first enable signal SP enable signal is turned on, and the second enable signal TP enable signal is disabled. The main circuit of the silicon carbide inverter contains 6 independent output connection points, which are single-phase AC inverter outputs. The 6 independent output connection points are divided into two single-phase AC output connection points, and 3 output connection points with the same electrical performance form the same output, realizing single-phase AC output and connecting with the outside. Figure 1 A11, A12, and A13 have the same electrical performance, and the three output connection points form the same output, which is in a parallel relationship and constitutes one end of the single-phase AC output. B11, B12, and B13 have the same electrical performance, and the three output connection points form the same output, which is in a parallel relationship and constitutes the other end of the single-phase AC output.

[0060] The operating mode 2 TP mode of the programmable drive interconnection control module QD1 is selected, the first enable signal SP enable signal is disabled, and the second enable signal TP enable signal is enabled. When the SP enable signal is disabled, the SP enable signal is at a low level, and the AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, and D6 are forced to output a low level, and all drive signals connected to the AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, and D6 are invalid. When the TP enable signal is turned on, the TP enable signal is at a high level, and the pins of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 connected to the TP enable signal are at a high level, and the other input pins of AND gates A1 and C1 are connected to the PWM1 drive signal, and the other input pins of AND gates A2 and C2 are connected to the PWM2 drive signal, and the other input pins of AND gates A3 and C3 are connected to the PWM3 drive signal, and the other input pins of AND gates A4 and C4 are connected to the PWM4 drive signal, and the other input pins of AND gates A5 and C5 are connected to the PWM5 drive signal, and the other input pins of AND gates A6 and C6 are connected to the PWM6 drive signal. The output changes of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 are the same as the changes of the PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 drive signals. The two outputs of AND gate A1 and B1 are connected to the input pin of OR gate X1, the two outputs of AND gate A2 and B2 are connected to the input pin of OR gate X2, the two outputs of AND gate A3 and B3 are connected to the input pin of OR gate X3, the two outputs of AND gate A4 and B4 are connected to the input pin of OR gate X4, the two outputs of AND gate A5 and B5 are connected to the input pin of OR gate X5, the two outputs of AND gate A6 and B6 are connected to the input pin of OR gate X6, the two outputs of AND gate C1 and D1 are connected to the input pin of OR gate Y1, the two outputs of AND gate C2 and D2 are connected to the input pin of OR gate Y2, the two outputs of AND gate C3 and D3 are connected to the input pin of OR gate Y3, the two outputs of AND gate C4 and D4 are connected to the input pin of OR gate Y4. The two outputs of AND gates C5 and D5 are connected to the input pin of OR gate Y5, and the two outputs of AND gates C6 and D6 are connected to the input pin of OR gate Y6. When the outputs of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, and D6 are low, the outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, and Y6 change, and the outputs of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 change, and the PWM drive signals connected to the pins of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, and C6 change.The outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, and Y6 are respectively connected to drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, and 62. The drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, and 62 respectively control silicon carbide MOSFET modules V11, V21, V31, V41, V51, V61, V12, V22, V32, V42, V52, and V62. That is, the PWM1 drive signal controls V11 and V12, the PWM2 drive signal controls V21 and V22, the PWM3 drive signal controls V31 and V32, the PWM4 drive signal controls V41 and V42, the PWM5 drive signal controls V51 and V52, and the PWM6 drive signal controls V61 and V62, so that the 12 silicon carbide MOSFET modules can realize three-phase AC inverter.

[0061] The working mode 2 TP mode of the programmable drive interconnection control module QD1 is selected, the first enable signal SP enable signal is disabled, and the second enable signal TP enable signal is enabled. The 6 independent output connection points are divided into three output connection points of three-phase AC, which is a three-phase AC inverter output. Two output connection points with the same electrical performance form the same output, realizing three-phase AC output and connecting with the outside. Figure 1 A11 and B11 have the same electrical performance, and the two output connection points form the same output, which is in parallel relationship, forming a three-phase AC A phase output. A12 and B12 have the same electrical performance, and the two output connection points form the same output, which is in parallel relationship, forming a three-phase AC B phase output. A13 and B13 have the same electrical performance, and the two output connection points form the same output, which is in parallel relationship, forming a three-phase AC C phase output.

[0062] The embedded controller includes 6 PWM drive signal outputs PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6, and 2 enable signal outputs TP and SP. The drive connection circuit inside the programmable drive interconnection control module is selected by the 2 enable signal outputs TP and SP. When the 2 enable signal outputs TP and SP are both low or high, the programmable drive interconnection control module prohibits driving and controlling two groups of silicon carbide MOSFET modules. The embedded controller includes three drive control modes. In control mode 1, the 2 PWM drive signal outputs PWM1 and PWM2 of the embedded controller are modulated according to the single-phase SPWM mode, and the first enable signal SP enable signal of the programmable drive interconnection control module is controlled to be turned on, and the second enable signal TP enable signal is prohibited, so as to complete the working mode selection of the programmable drive interconnection control module. The 2 PWM drive signal outputs PWM1 and PWM2 modulated by the single-phase SPWM control 12 silicon carbide MOSFET modules to realize single-phase AC inverter. Control mode 2: The embedded controller's 2-way PWM drive signal output PWM1 and PWM2 are modulated in a high-frequency resonance alternating conduction mode, and the first enable signal SP of the programmable drive interconnection control module is controlled to be turned on, and the second enable signal TP is disabled, completing the selection of the working mode of the programmable drive interconnection control module. The 2-way PWM drive signal output PWM1 and PWM2 modulated in a high-frequency resonance alternating conduction mode control 12 silicon carbide MOSFET modules to achieve single-phase AC inverter. Control mode 3: The embedded controller's 6-way PWM drive signal output PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 are modulated in a three-phase SPWM mode, and the first enable signal SP of the programmable drive interconnection control module is controlled to be disabled, and the second enable signal TP is enabled, completing the selection of the working mode of the programmable drive interconnection control module. The 6-way SPWM drive signal output PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 modulated in a three-phase SPWM mode control 12 silicon carbide MOSFET modules to achieve three-phase AC inverter.

[0063] Control mode 1, PWM drive control Figure 3As shown, the PWM3, PWM4, PWM5, and PWM6 drive signals are low level, and the 2-way PWM drive signal output PWM1 and PWM2 are modulated in single-phase SPWM mode. The PWM1 drive signal controls V11, V31, V51, V22, V42, and V62, that is, the PWM2 drive signal controls V21, V41, V61, V12, V32, and V52. The single-phase SPWM modulated PWM1 and PWM2 control 12 silicon carbide MOSFET modules to achieve single-phase AC inverter. AC1 is the single-phase AC output that needs to be controlled, and VSAN is a triangular carrier. The AC1 with different frequencies and amplitudes is compared with the triangular carrier of VSAN to generate 2-way PWM1 and PWM2 silicon carbide MOSFET module drive signals modulated and output in single-phase SPWM mode.

[0064] Control mode 2, PWM drive control Figure 4 As shown, the PWM3, PWM4, PWM5, and PWM6 drive signals are low level, and the two PWM drive signal outputs PWM1 and PWM2 are modulated in the high-frequency resonance alternating conduction mode. The PWM1 drive signal controls V11, V31, V51, V22, V42, and V62, that is, the PWM2 drive signal controls V21, V41, V61, V12, V32, and V52. PWM1 and PWM2 modulated in the high-frequency resonance alternating conduction mode control 12 silicon carbide MOSFET modules to achieve single-phase AC inverter. In the high-frequency resonance alternating conduction mode, the PWM1 and PWM2 drive signals are alternately turned on, and the pulse width of PWM1 and PWM2 is greater than or equal to half of the resonance period. I1 is the high-frequency resonance current, that is, the pulse width of PWM1 and PWM2 is greater than or equal to the time when the high-frequency resonance current of I1 passes through the zero point.

[0065] Control mode three, PWM drive control Figure 5As shown, the 6-way PWM drive signal output PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 are modulated in the three-phase SPWM mode. The PWM1 drive signal controls V11 and V12, the PWM2 drive signal controls V21 and V22, the PWM3 drive signal controls V31 and V32, the PWM4 drive signal controls V41 and V42, the PWM5 drive signal controls V51 and V52, and the PWM6 drive signal controls V61 and V62. The 6-way SPWM drive signal output PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 modulated by three-phase SPWM control 12 silicon carbide MOSFET modules to realize three-phase AC inverter. A, B, and C are three-phase ACs with a phase difference of 120° that need to be controlled. VSAN is a triangular carrier. The three-phase ACs of A, B, and C with different frequencies and amplitudes are compared with the same VSAN as a triangular carrier to generate 6-way PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 silicon carbide MOSFET module drive signals modulated and output in the three-phase SPWM mode.

[0066] Embedded controllers such as Figure 7 As shown, the embedded controller is based on a digital signal processor or a single-chip microcomputer. In addition to 6-way PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 drive signal outputs and 2-way TP and SP enable signal outputs, it also includes multiple analog inputs AI1, AI2, AI3, AI4, AI5, AI6, AI7, and AI8, multiple digital switch inputs DI1, DI2, DI3, DI4, DI5, and DI6, multiple digital switch outputs DO1, DO2, DO3, DO4, DO5, and DO6, and multiple communication ports COM1 and COM2, so as to monitor the input voltage, input current, output voltage, output current, operating temperature and other parameters of the high-voltage power supply operation parameters, as well as feedback closed-loop control, so as to facilitate the upgrading and transformation of other types of high-voltage power supplies.

[0067] Application of silicon carbide MOSFET inverter: The same silicon carbide MOSFET inverter hardware can be used to change the control mode by software to realize the transformation of single-phase thyristor regulation control, three-phase thyristor regulation control, IGBT module single or three-phase variable frequency power supply, and IGBT module high-frequency single-phase power supply of different systems.

[0068] A specific application example of a silicon carbide inverter and a control method thereof: In the control mode of the silicon carbide inverter, a schematic diagram of a modification scheme for replacing a single-phase thyristor regulation control circuit in a high-voltage power supply is shown in FIG. Figure 7As shown. According to the breakpoints, remove the connection between the single-phase thyristor regulation control circuit and the industrial frequency power distribution, and remove the connection with the single-phase step-up rectifier transformer. The power input terminals of the silicon carbide inverter A, B, and C are connected to the three-phase industrial frequency AC. The single-phase step-up rectifier transformer and the connecting cable in the figure can be reused. The silicon carbide inverter outputs A11, A12, and A13 are connected to one end of the primary coil of the single-phase step-up rectifier transformer through a cable, and the silicon carbide inverter outputs B11, B12, and B13 are connected to the other end of the primary coil of the single-phase step-up rectifier transformer through a cable to complete the transformation. After the silicon carbide inverter is transformed, the regulation control is upgraded from a semi-controlled device to a fully controlled device. When the high-voltage power supply has a high-voltage breakdown, it can be immediately shut down for protection. Compared with the thyristor voltage regulation, the SPWM regulation method of the silicon carbide inverter can effectively suppress the generation of harmonics and reduce pollution to the power grid. The SPWM voltage regulation technology of silicon carbide inverter changes the output frequency. Increasing the frequency can reduce the core iron loss of the single-phase rectifier transformer and improve the power supply efficiency. The SPWM voltage regulation technology of silicon carbide inverter can accurately control the primary input voltage amplitude of the single-phase transformer, thereby accurately controlling the output voltage of the high-voltage power supply and improving the adaptability of the high-voltage power supply to working conditions.

[0069] A specific application example 2 of a silicon carbide inverter and a control method thereof: When the silicon carbide inverter is in control mode 2, the schematic diagram of the transformation scheme of replacing the IGBT control circuit in the high-voltage power supply is shown in FIG. Figure 8 As shown. Remove the connection between the IGBT control circuit and the industrial frequency power distribution according to the breakpoints, and remove the connection with the high-frequency boost rectifier transformer. The power input terminals of the silicon carbide inverter A, B, and C are connected to the three-phase industrial frequency AC. The high-frequency boost rectifier transformer and the connecting cable in the figure can be reused. The silicon carbide inverter outputs A11, A12, and A13 are connected to one end of the primary coil of the high-frequency boost rectifier transformer through a cable, and the silicon carbide inverter outputs B11, B12, and B13 are connected to the other end of the primary coil of the high-frequency boost rectifier transformer through a cable to complete the transformation. After the silicon carbide inverter is transformed, the regulation control is upgraded from the IGBT module to the silicon carbide MOSFET module. The silicon carbide MOSFET module has lower switching losses, which helps to reduce losses and improve efficiency. The silicon carbide MOSFET module has a higher operating frequency, which can increase the inverter operating frequency. Increasing the frequency can reduce the iron loss of the high-frequency rectifier transformer core and improve power efficiency.

[0070] A specific application example 3 of a silicon carbide inverter and its control method: Schematic diagram of the scheme for replacing the three-phase thyristor regulation control circuit in the high-voltage power supply when the silicon carbide inverter is in control mode 3. Fig. 9As shown. According to the breakpoints, the connection between the three-phase thyristor regulation control circuit and the power distribution of the industrial frequency power supply is removed, and the connection with the three-phase boost rectifier transformer is removed. The power input terminals A, B, and C of the silicon carbide inverter are connected to the three-phase industrial frequency AC. The three-phase boost rectifier transformer and the connecting cable in the figure can be reused. The outputs A11 and B11 of the silicon carbide inverter are connected to the primary coil A of the three-phase boost rectifier transformer through cables, and the outputs A12 and B12 of the silicon carbide inverter are connected to the primary coil B of the three-phase boost rectifier transformer through cables. The outputs A13 and B13 of the silicon carbide inverter are connected to the primary coil C of the three-phase boost rectifier transformer through cables to complete the transformation. After the silicon carbide inverter is transformed, the regulation control is upgraded from a semi-controlled device to a fully controlled device. When the high-voltage power supply has a high-voltage breakdown, it can be immediately shut down for protection. Compared with the thyristor voltage regulation, the SPWM regulation method of the silicon carbide inverter can effectively suppress the generation of harmonics and reduce pollution to the power grid. The SPWM voltage regulation technology of silicon carbide inverter changes the output frequency. Increasing the frequency can reduce the core iron loss of the three-phase rectifier transformer and improve the power supply efficiency. The SPWM voltage regulation technology of silicon carbide inverter can accurately control the primary input voltage amplitude of the three-phase transformer, thereby accurately controlling the output voltage of the high-voltage power supply and improving the adaptability of the high-voltage power supply to working conditions.

[0071] Special statement: The "embodiment" and the like described in this specification refer to the specific features, elements or characteristics described in conjunction with the embodiment included in the embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not limit the specific reference to the same embodiment. In other words, when describing a specific feature, element or characteristic in conjunction with any embodiment, it is claimed that such feature, element or characteristic is implemented in conjunction with other embodiments and is included in the scope of the claims for protection of the present invention; the embodiment describes the present invention with reference to multiple explanatory embodiments of the logical architecture and ideas of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can design many other modifications and implementation methods within the framework of the technical solution of the present invention, and can make various non-essential modifications and improvements to the key points of the technical solution. For those skilled in the art, other uses will also be obvious, and non-substantial changes or replacements that can be easily thought of will be implemented. These modifications and implementation methods will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A silicon carbide inverter, characterized in that: It includes a three-phase industrial frequency AC power input connection point, a three-phase rectifier filter with an integrated buffer circuit, two groups of silicon carbide MOSFET modules and their drive circuits, a programmable drive interconnection control module, an embedded controller, and 6 independent output connection points; the output of the programmable drive interconnection control module is connected to the drive circuit of the two groups of silicon carbide MOSFET modules; the input of the programmable drive interconnection control module is connected to the output of the embedded controller; the embedded controller includes three drive control modes to achieve different outputs of the 6 independent output connection points, corresponding to different working scenarios: control mode 1 is modulated according to the single-phase SPWM mode to achieve single-phase AC inversion; control mode 2 is modulated according to the high-frequency resonant alternating conduction mode to achieve single-phase high-frequency AC inversion; control mode 3 is modulated according to the three-phase SPWM mode to achieve three-phase AC inversion.

2. The silicon carbide inverter according to claim 1, characterized in that: In the control of the programmable drive interconnection control module, the high-frequency drive control formula of the silicon carbide MOSFET is calculated in combination with the operating temperature factor of the silicon carbide MOSFET: Where: fw is the operating frequency, k is the correction coefficient, Vs is the AC output voltage, fs is the switching frequency, Ls is the harmonic suppression inductor, fL is the inductor harmonic frequency, fC is the capacitor harmonic frequency, fsw is the switching frequency, Tmax is the maximum allowable operating temperature of the silicon carbide MOSFET, and Ta is the actual operating temperature of the silicon carbide MOSFET.

3. The silicon carbide inverter according to claim 1, characterized in that: The two groups of silicon carbide MOSFET modules each include 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules correspond to 6 driving circuits respectively.

4. The silicon carbide inverter according to claim 1, characterized in that: The programmable drive interconnection control module includes 12 PWM outputs, 6 PWM drive signal inputs, and 2 enable signal inputs. The 12 PWM outputs are connected to 12 drive circuits of two groups of silicon carbide MOSFET modules, and the 6 PWM drive signal inputs and 2 enable signal inputs are connected to the 6 PWM drive signal outputs and 2 enable signals of the embedded controller; a microcontroller MCU and a field programmable gate array FPGA are configured to realize high-speed calculation and execution of the drive control strategy, quickly sample the load current and use a PID controller for real-time adjustment to realize a dynamic load tracking function, so as to improve the dynamic response speed and stability of the inverter by intelligent drive control; The microcontroller MCU is used to implement an automatic adaptive dead time control algorithm. According to the load changes, the width of the dead time is adjusted in real time. The dead time calculation formula is: Td=(√2*π) / (3*Vs*Ls*(fs^2-fpwm^2)), where: Td is the dead time, Vs is the source voltage, Ls is the source inductance, fs is the corresponding switching frequency, and fpwm is the pulse width modulation frequency.

5. The silicon carbide inverter according to claim 4, characterized in that: When the two enable signal inputs are at a low level or a high level, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules.

6. The silicon carbide inverter according to claim 4, characterized in that: The two enable signal inputs select the working mode. When the first enable signal is enabled, the two PWM drive signal inputs control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules realize single-phase AC inversion.

7. The silicon carbide inverter according to claim 4, characterized in that: The two enable signal inputs select the working mode. When the second enable signal is enabled, the six PWM drive signal inputs control the 12 PWM outputs, so that the 12 silicon carbide MOSFET modules realize three-phase AC inverter.

8. The silicon carbide inverter according to claim 1, characterized in that: The six independent output connection points are changed according to the two-way enable signal input of the programmable drive interconnection control module. When the first enable signal is enabled, the six independent output connection points are divided into two single-phase AC output connection points, and three output connection points with the same electrical performance form the same output, realizing single-phase AC output and connecting to the outside; when the second enable signal is enabled, the six independent output connection points are divided into three three-phase AC output connection points, and two output connection points with the same electrical performance form the same output, realizing three-phase AC output and connecting to the outside.

9. The silicon carbide inverter according to claim 1, characterized in that: The embedded controller includes 6 PWM drive signal outputs and 2 enable signal outputs. The drive connection circuit inside the programmable drive interconnection control module is selected through the 2 enable signal outputs. When the 2 enable signal outputs are simultaneously at a low level or simultaneously at a high level, the programmable drive interconnection control module prohibits driving and controlling two groups of silicon carbide MOSFET modules.

10. The silicon carbide inverter according to claim 9, characterized in that: The embedded controller is based on a digital signal processor or a single-chip microcomputer. In addition to 6-way PWM drive signal output and 2-way enable signal output, it also includes multiple analog inputs, multiple digital switch inputs, multiple digital switch outputs, and multiple communication ports to realize the monitoring of high-voltage power supply operating parameters such as input voltage, input current, output voltage, output current, operating temperature, etc., as well as feedback closed-loop control.

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