A silicon carbide inverter and its control method

Abstract

A silicon carbide inverter and its control method mainly include a three-phase power frequency AC power input connection point, a three-phase rectifier filter integrated with a 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 silicon carbide MOSFET modules are divided into two groups, and each group has 6 silicon carbide MOSFETs and corresponding drive circuits. The programmable drive interconnection control module can select the working mode according to different enable signals to achieve single-phase or three-phase AC inversion, and calculate and optimize the control of the high frequency of the silicon carbide MOSFETs in combination with the working temperature factor of the silicon carbide MOSFETs. The embedded controller controls the single-phase or three-phase AC inversion of the silicon carbide MOSFET modules, and can monitor and feedback closed-loop control of the operating parameters of the high-voltage power supply. The silicon carbide inverter realizes multi-mode selection control and intelligent safety and efficiency control.

Description

Technical Field

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

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

[0003] According to the classification standards of the environmental protection industry, common types of high-voltage power supplies include single-phase thyristor-regulated high-voltage power supplies, three-phase thyristor-regulated high-voltage power supplies, high-frequency high-voltage power supplies, variable-frequency high-voltage power supplies, etc. High-voltage power supply distribution is generally three-phase power-frequency AC power, mainly divided into an adjustment control part and a high-voltage boost rectification part.

[0004] For single-phase thyristor-regulated high-voltage power supplies and three-phase thyristor-regulated high-voltage power supplies, the control part directly performs amplitude modulation on the power-frequency AC power, and the working frequency is the power grid frequency of 50 / 60HZ. When the control angle (trigger angle) of the thyristor increases, its power factor will decrease. There is an unconducted working time within the AC half-wave cycle of the power grid, and the electric energy provided by the power 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 power grid frequency. These harmonic components will not only reduce the power supply efficiency but also cause harmonic pollution to the power grid, affecting the normal operation of other equipment. At the same time, thyristors belong to semi-controlled devices, which are uncontrollable after conduction, and their working frequency is the power grid frequency, with a slow dynamic response speed and poor working condition adaptability. However, due to the simple circuit and low cost of thyristor voltage regulation, its market share is still very large.

[0005] For high-frequency high-voltage power supplies, the control part is a high-frequency inverter circuit that rectifies three-phase power-frequency AC power into DC and then inverses it into high-frequency AC through a silicon semiconductor IGBT module. At high currents, the silicon semiconductor IGBT module has high switching losses and a large reverse recovery current. In order to limit the switching losses and ensure the reliable operation of the inverter, the working frequency of the silicon semiconductor IGBT module in the high-frequency high-voltage power supply inverter generally does not exceed twenty kilohertz. The high switching losses of the silicon semiconductor IGBT module restrict the improvement of the high-voltage power supply efficiency, and the limitation of the working 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 working frequency of the inverter. The higher the frequency, the smaller the volume.

[0006] In recent years, with the development of the electric vehicle and new energy industries, the third-generation silicon carbide semiconductor technology has begun large-scale mass production and batch applications. Silicon carbide MOSFETs have a highly stable crystal structure and a relatively high energy band width. Their operating frequency is much higher than that of silicon semiconductor IGBT modules. At the same time, they have excellent high-temperature operating characteristics and low switching losses, making them very suitable for applications in high-voltage power supplies. The existing technologies in this area are as follows.

[0007] Chinese invention patent CN108023493A, a device for reducing the common-mode voltage amplitude of a silicon carbide inverter, 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 real-time three-phase duty cycles under the goal of minimizing current ripple loss and generate corresponding three-phase switching sequences. The digital processing circuit includes a power supply circuit, a digital operation chip, a sampling circuit, input / output ports, and peripheral circuits. The drive circuit generates drive signals for the corresponding silicon carbide devices according to the switching sequence signals output by the current ripple minimum common-mode voltage reduction PWM. The three-phase silicon carbide inverter module controls the turn-on and turn-off of the silicon carbide devices according to the drive signals sent by the drive circuit, and the load is connected to the three-phase silicon carbide inverter module.

[0008] Chinese invention patent CN112104246A, a low-harmonic control system and method for a three-level high-switching-frequency silicon carbide inverter, discloses that the low-harmonic control system includes an amplitude adjustment module, a selection module, a modulation wave superposition module, an amplitude limit 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 judges the size of the original modulation wave and outputs different amplitude adjustment amounts. The modulation wave adjustment module performs a superposition operation on the amplitude-adjusted modulation wave. The amplitude limit module limits the amplitude of the modulation wave obtained by each superposition. The drive signal generation module is used to drive the silicon carbide power switching devices in the main circuit. The main circuit of the three-level high-switching-frequency silicon carbide inverter contains 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, a high-efficiency and low-harmonic control method for a high-switching-frequency silicon carbide inverter, discloses that after the fundamental wave current extraction module extracts the fundamental wave of the output current of the high-switching-frequency silicon carbide inverter, it is used as the basis for judging the current interval, obtaining an accurate current interval, and eliminating the influence of the high-frequency harmonics of the output current on the current interval judgment. The high-efficiency and low-harmonic modulation module includes four sub-modules: current interval judgment, modulation wave amplitude adjustment, zero-sequence component calculation, and logic synthesis. In different current intervals, through the modulation wave amplitude adjustment sub-module, the purpose of compensating for the dead-time effect of the high-switching-frequency silicon carbide inverter is achieved; through the zero-sequence component calculation sub-module, the purpose of reducing the switching loss of the high-switching-frequency silicon carbide inverter is achieved; the logic synthesis module adds a dead-time output drive signal. The present invention effectively combines dead-time compensation and reduction of switching loss to achieve high-efficiency and low-harmonic operation of the high-switching-frequency silicon carbide inverter.

[0010] For these inverters using silicon carbide MOSFETs, some require re-wiring, which is inconvenient for the transformation of old circuits. Some have a large room for improvement in the performance of the high-voltage power supply, and the high cost causes waste of resources. Summary of the Invention

[0011] In view of the problems described in the background art, the present invention proposes a novel silicon carbide inverter and its control method to improve the performance of the high-voltage power supply, make use of the original cables and the high-voltage boost rectification part, control costs, reduce resource waste, and improve the overall performance of the old high-voltage power supply. The specific technical solutions are as follows:

[0012] A silicon carbide inverter includes a three-phase power frequency AC power input connection point, a three-phase rectifier filter integrated with a 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 embedded controller includes three drive control modes, corresponding to different working scenarios: Control mode one is modulated according to the single-phase SPWM mode to achieve single-phase AC inversion; Control mode two is modulated according to the high-frequency resonance alternating conduction mode to also achieve single-phase AC inversion; Control mode three is modulated according to the three-phase SPWM mode to achieve three-phase AC inversion.

[0013] The programmable drive interconnection control module combines the working temperature factor of the silicon carbide MOSFET to calculate the high-frequency drive control formula of the silicon carbide MOSFET:

[0014]

[0015] 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.

[0016] The two groups of silicon carbide MOSFET modules each include 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules respectively correspond to 6 drive circuits.

[0017] 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 the 12 drive circuits of the two groups of silicon carbide MOSFET modules. 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. Configure a microcontroller MCU and a field-programmable gate array FPGA to achieve 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 achieve the dynamic load tracking function, and improve the dynamic response speed and stability of the inverter through intelligent drive control. Implement an automatic adaptive dead-time control algorithm through the microcontroller MCU, and adjust the width of the dead time in real time according to the change of the load. The calculation formula for the dead time 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 inductor, fs is the corresponding switching frequency, and fpwm is the pulse width modulation frequency.

[0018] When the 2 enable signal inputs are at low level or high level, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules.

[0019] The 2 enable signal inputs select the operating mode. When the first enable signal is enabled, the 2 PWM drive signal inputs control the 12 PWM outputs, enabling the 12 silicon carbide MOSFET modules to achieve single-phase AC inversion.

[0020] The 2 enable signal inputs select the operating mode. When the second enable signal is enabled, the 6 PWM drive signal inputs control the 12 PWM outputs, enabling the 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

[0021] The six independent output connection points change according to the input of two enable signals of the programmable drive interconnection control module. When the first enable signal is enabled, the six independent output connection points are divided into two output connection points for single-phase alternating current, and three output connection points with the same electrical performance form the same output to achieve single-phase alternating current output and connect to the outside; when the second enable signal is enabled, the six independent output connection points are divided into three output connection points for three-phase alternating current, and two output connection points with the same electrical performance form the same output to achieve three-phase alternating current output and connect to the outside.

[0022] The embedded controller includes six PWM drive signal outputs and two enable signal outputs. The drive connection circuit inside the programmable drive interconnection control module is selected through the two enable signal outputs. When the two enable signal outputs are both low level or both high level at the same time, the programmable drive interconnection control module prohibits driving and controlling two groups of silicon carbide MOSFET modules.

[0023] The embedded controller takes a digital signal processor or a single-chip microcomputer as the core. In addition to six PWM drive signal outputs and two enable signal outputs, it also includes multiple analog quantity inputs, multiple digital switch quantity inputs, multiple digital switch quantity outputs, and multiple communication ports to achieve monitoring of the operating parameters of the high-voltage power supply such as input voltage, input current, output voltage, output current, operating temperature, etc., as well as feedback closed-loop control.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0025] 1. A silicon carbide inverter and its control method implement three control mode methods using the same inverter hardware circuit. Without changing the hardware circuit and structure of the silicon carbide inverter, single-phase AC inversion, three-phase AC inversion, and high-frequency inversion can be achieved, which is applied to the new high-voltage power supply to improve the overall performance of the power supply. Combining the temperature factor of the silicon carbide MOSFET working with the high-frequency drive control algorithm of the silicon carbide MOSFET greatly improves the safety.

[0026] 2. A silicon carbide inverter and its control method take the silicon carbide MOSFET module as the core, can utilize the original connection cables and single-phase and three-phase rectifier transformers of the high-voltage power supply, and perform frequency conversion control transformation on single-phase and three-phase semi-controlled thyristor high-voltage power supplies. Utilize the original cables and the high-voltage boost rectification part, reduce the control cost, waste of resources, improve the overall performance of the old high-voltage power supply, greatly improve the power supply efficiency, reduce the grid harmonic interference, improve the working condition adaptability, and have a low transformation cost.

[0027] 3. A silicon carbide inverter and its control method, with a silicon carbide MOSFET module as the core, has low switching losses and a high operating frequency. It can reuse the connection cables of the original high-voltage power supply and the high-frequency and variable-frequency rectifier transformers to upgrade and transform the silicon IGBT-controlled high-frequency and variable-frequency high-voltage power supply, reduce switching losses, and improve power supply efficiency.

[0028] 4. A silicon carbide inverter and its control method, using silicon carbide inverters of the same power rating, can be applied to different types of high-voltage power supplies with the same power rating, which is conducive to achieving standardized production and reducing the inventory of products and material warehouses.

[0029] 5. A silicon carbide inverter and its control method use a multi-functional programmable drive interconnection control module. This module includes 12 PWM outputs, 6 PWM drive signal inputs, and 2 enable signal inputs, and can achieve complex connections and controls with the drive circuit and embedded controller of the silicon carbide MOSFET module. Different operating modes can be selected through the 2 enable signal inputs to achieve single-phase AC inversion and three-phase AC inversion, with high flexibility and adaptability.

[0030] 6. For a silicon carbide inverter and its control method, the 6 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 for single-phase AC, and 3 output connection points with the same electrical performance form the same output to achieve single-phase AC output and external connection; when the second enable signal is enabled, it is divided into three output connection points for three-phase AC, and 2 output connection points with the same electrical performance form the same output to achieve three-phase AC output and external connection. This flexible output connection method is difficult to achieve in the prior art.

[0031] 7. A silicon carbide inverter and its control method, the embedded controller includes three drive control modes, corresponding to different working scenarios respectively: control mode one is modulated according to the single-phase SPWM mode to achieve single-phase AC inversion; control mode two is modulated according to the high-frequency resonance alternating conduction mode to also achieve single-phase AC inversion; control mode three is modulated according to the three-phase SPWM mode to achieve three-phase AC inversion. Different modes provide more choices for users and can be switched according to specific situations. This diverse drive control mode provides more choices for users to meet different application requirements.

[0032] 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 the conventional PWM drive signal output and enable signal output, it 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 the operating parameters of the high-voltage power supply, facilitating the upgrade and transformation of other types of high-voltage power supplies, and overcoming the defect that the embedded controller in the prior art may be relatively weak in terms of function integration and scalability.

[0033] 9. A silicon carbide inverter and its control method, which monitors the operating parameters through an embedded controller and performs feedback closed-loop control, with accurate output. The embedded controller can real-time monitor parameters such as input voltage, input current, output voltage, output current, operating temperature, etc., and precisely adjust the output through feedback closed-loop control to ensure that the alternating current output by the inverter is stable and reliable, meeting the requirements of various high-precision devices.

[0034] 10. A silicon carbide inverter and its control method, the integration of the buffer circuit effectively reduces the voltage spikes in the circuit, reducing 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 devices.

[0035] 11. A silicon carbide inverter and its control method, the characteristics of silicon carbide material make the inverter suitable for high-dynamic-performance occasions. The fast switching characteristics of silicon carbide enable the inverter to respond to changes in input signals within 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, etc. The high thermal conductivity of silicon carbide material helps to improve the heat dissipation performance of the inverter and extend the equipment life. The silicon carbide material with high thermal conductivity can quickly dissipate the heat generated during the operation of the inverter, reducing 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 the maintenance cost. Description of the Drawings

[0036] Figure 1 is the circuit schematic diagram of a silicon carbide inverter and its control method.

[0037] Figure 2 is the schematic diagram of the programmable drive interconnection control module of a silicon carbide inverter and its control method.

[0038] Figure 3 is the drive waveform diagram of control mode 1 of a silicon carbide inverter and its control method.

[0039] Figure 4It is the drive waveform diagram of control mode 2 of a silicon carbide inverter and its control method.

[0040] Figure 5 It is the drive waveform diagram of control mode 3 of a silicon carbide inverter and its control method.

[0041] Figure 6 It is the charging control waveform diagram of the three-phase rectifier filter of the integrated buffer circuit of a silicon carbide inverter and its control method.

[0042] Figure 7 It is the embedded controller of a silicon carbide inverter and its control method.

[0043] Figure 8 When the control mode of a silicon carbide inverter and its control method is 1, it is the schematic diagram of the transformation scheme to replace the single-phase thyristor regulating control circuit in the high-voltage power supply. The single-phase step-up rectifier transformer in the figure can be reused.

[0044] Figure 9 When the control mode of a silicon carbide inverter and its control method is 2, it is the schematic diagram of the transformation scheme to replace the IGBT control circuit in the high-voltage power supply. The high-frequency step-up rectifier transformer in the figure can be reused.

[0045] Figure 10 When the control mode of a silicon carbide inverter and its control method is 2, it is the schematic diagram of the transformation scheme to replace the three-phase thyristor regulating control circuit in the high-voltage power supply. The three-phase step-up rectifier transformer in the figure can be reused.

[0046] In the attached drawings: M1 and M2 are silicon carbide MOSFET modules; Time (ms) is the abscissa with the unit of millisecond; A11, A12, A13, B11, B12, and B13 are the output connection points of the silicon carbide inverter. When performing single-phase AC inversion, one end of A11, A12, and A13 outputs, and the other end of B11, B12, and B13 outputs. When performing three-phase AC inversion, A11 and B11 are the A-phase output, A12 and B12 are the B-phase output, and A13 and B13 are the C-phase output; QD1 is a programmable drive interconnection control module; PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 are the PWM drive signal outputs of the embedded controller; TP is the enable signal output of the programmable drive interconnection control module and the embedded controller; SP 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 the multi-channel analog quantity inputs of the embedded controller, used for monitoring the operating parameters of the high-voltage power supply; DI1, DI2, DI3, DI4, DI5, and DI6 are the multi-channel digital switch quantity inputs of the embedded controller, used for monitoring the operating parameters of the high-voltage power supply or other control functions; DO1, DO2, DO3, DO4, DO5, and DO6 are the multi-channel digital switch quantity outputs of the embedded controller, used for high-voltage power supply control or other output functions; VSAN is a triangular carrier wave; COM1 and COM2 are multiple communication ports of the embedded controller, used for high-voltage power supply communication control and upgrading of other types of high-voltage voltages. Detailed implementation mode

[0047] A silicon carbide inverter and its control method are powered by a three-phase industrial frequency AC power supply, and mainly include a three-phase industrial frequency AC power input connection point, a three-phase rectifier filter integrated with a 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 programmable drive interconnection control module calculates the high-frequency drive control formula of the silicon carbide MOSFET by combining the working temperature factor of the silicon carbide MOSFET:

[0048]

[0049] fw is the working 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 working temperature of the silicon carbide MOSFET, and Ta represents the actual working temperature of the silicon carbide MOSFET.

[0050] When the heat dissipation condition is poor, the operating frequency of the silicon carbide MOSFET generally needs to be reduced. This is because when operating at high frequencies, the silicon carbide MOSFET generates more heat. Therefore, a temperature factor, Tmax / Ta, is set to dynamically adjust the operating frequency. When Ta is close to Tmax, the ratio Tmax / Ta approaches 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.

[0051] Two groups of silicon carbide MOSFET modules and their drive circuits: Two groups of silicon carbide MOSFET modules, each group includes 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules respectively correspond to 6 drive circuits.

[0052] 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 low level or 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, enabling 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. When the second enable signal is enabled, the 6 PWM drive signal inputs control the 12 PWM outputs, enabling 12 silicon carbide MOSFET modules to achieve three-phase AC inversion; Configure the microcontroller MCU, and the field-programmable gate array FPGA realizes the high-speed calculation and execution of the drive control strategy, quickly samples the load current and uses the PID (Proportional-Integral-Differential) controller for real-time adjustment to achieve the dynamic load tracking function, improving the dynamic response speed and stability of the inverter with intelligent drive control; The automatic adaptive dead-time control algorithm is realized through the microcontroller MCU. According to the change of the load, the width of the corresponding dead-time is adjusted in real time to ensure the stable operation and high efficiency of the inverter under different loads. The calculation formula for the dead-time 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.

[0053] Six independent output connection points of the silicon carbide inverter: The six independent output connection points of the silicon carbide inverter change according to the 2 enable signal inputs of the programmable drive interconnection control module. When the first enable signal is enabled, the six independent output connection points are divided into two output connection points for single-phase AC. 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 output connection points for three-phase AC. Two output connection points with the same electrical performance form the same output, realizing three-phase AC output and connecting to the outside.

[0054] 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 both 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 one, 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 enabled to complete the working mode selection of the programmable drive interconnection control module. The 2 PWM drive signal outputs modulated by the single-phase SPWM control 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. In control mode two, 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 enabled to complete the working mode selection of the programmable drive interconnection control module. 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 inversion. In control mode three, the 6 PWM drive signal outputs of the embedded controller are modulated according to the three-phase SPWM mode, and the second enable signal of the programmable drive interconnection control module is enabled to complete the working mode selection of the programmable drive interconnection control module. The 6 SPWM drive signal outputs modulated by the three-phase SPWM control 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

[0055] Embedded Controller: The embedded controller uses a digital signal processor or a single-chip microcomputer as the core. In addition to 6 PWM drive signal outputs and 2 enable signal outputs, it also includes multiple analog input channels, multiple digital switch input channels, multiple digital switch output channels, and multiple communication ports to monitor the operating parameters of the high-voltage power supply such as input voltage, input current, output voltage, output current, operating temperature, etc., and perform feedback closed-loop control, which is convenient for upgrading and transforming other types of high-voltage power supplies.

[0056] Specific Embodiment of a Silicon Carbide Inverter and Its Control Method: The circuit schematic diagram of a silicon carbide inverter and its control method is as Figure 1 shown.

[0057] It is powered by a three-phase industrial frequency AC power supply, mainly including three-phase industrial frequency AC power input connection points, a three-phase rectifier filter integrated with a 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.

[0058] The three-phase industrial frequency AC power supply is connected to the three-phase industrial frequency AC power input connection points A, B, and C.

[0059] Three-phase rectifier filter integrated with a buffer circuit, whose main function is to convert a three-phase power-frequency AC power supply into a DC power supply to supply power to a silicon carbide inverter circuit. At the same time, the integrated buffer circuit pre-fills the filter capacitor of the three-phase rectifier filter before the pulse power supply works, reducing the large current impact on the three-phase power-frequency power supply when the capacitor is charging. For the specific circuit, the three-phase power-frequency AC power supply is connected to a three-phase rectifier circuit composed of power diodes D1, D2, D3 and power thyristors VT1, VT2, VT3. Capacitor C1 filters the power-frequency AC rectification and outputs a stable DC power. The control circuit of the three-phase rectifier circuit, the power thyristors VT1, VT2, VT3 are controlled by a trigger control circuit composed of relay K1, current-limiting resistors Ra, Rb, Rc, and small-current diodes Da, Db, Dc. By the conduction or disconnection of relay K1, the conduction and disconnection of the three-phase rectifier circuit are controlled. The buffer circuit is composed of small-current diode D4, power diodes D2, D3, current-limiting resistor R1, and relay K2. By the conduction or disconnection of relay K2, the conduction and disconnection of the buffer circuit are controlled. Before the power supply works, relay K2 is controlled to be energized through control point 2, and the buffer circuit charges capacitor C1. After the voltage of capacitor C1 is charged to a high level, relay K1 is controlled to be energized through control point 1, reducing the large current impact on the three-phase power-frequency power supply during the zero-voltage charging of capacitor C1. After controlling relay K1 to be energized, the power thyristors VT1, VT2, VT3 are triggered and conduct, and the power three-phase rectifier circuit works. The buffer circuit is bypassed by the power three-phase rectifier circuit, and the buffer circuit work ends.

[0060] The three-phase rectifier filter integrated with a buffer circuit, the charging process is shown in Figure 6 , control point 2 controls relay K2 to be energized, DC voltage DC1 starts to rise. After a delay of 2 to 4 seconds, DC voltage DC1 rises to close to the normal working voltage, and control point 1 controls relay K1 to be energized, and DC voltage DC1 rises to the normal working voltage.

[0061] Two groups of silicon carbide MOSFET modules and their drive circuits. One group of silicon carbide MOSFET modules M1 consists of silicon carbide MOSFET modules V11, V21, V31, V41, V51, and V61. The silicon carbide MOSFETs V11, V21, V31, V41, V51, and V61 are respectively controlled by drive circuits 11, 21, 31, 41, 51, and 61, and the drive circuits 11, 21, 31, 41, 51, and 61 are respectively connected to the programmable drive interconnection control module QD1. The other group of silicon carbide MOSFET modules M2 consists of silicon carbide MOSFET modules V12, V22, V32, V42, V52, and V62. The silicon carbide MOSFETs V12, V22, V32, V42, V52, and V62 are respectively controlled by drive circuits 12, 22, 32, 42, 52, and 62, and the drive circuits 12, 22, 32, 42, 52, and 62 are respectively connected to the programmable drive interconnection control module QD1.

[0062] The programmable drive interconnection control module QD1 is designed using a complex programmable logic device CPLD or a field-programmable gate array FPGA. The 12 PWM outputs 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, and 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, and 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 the 2 enable signals of the embedded controller. When the 2 enable signal inputs TP and SP are both low or high, 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 TP and SP. When the first enable signal SP is enabled, the 2 PWM drive signal inputs PWM1 and PWM2 control the 12 PWM outputs, enabling the 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. When the second enable signal is enabled, the 6 PWM drive signal inputs PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 control the 12 PWM outputs, enabling the 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

[0063] The schematic diagram of the programmable drive interconnection control module QD1 is as Figure 2 shown.

[0064] For the selection of the first working mode (SP mode) of the programmable drive interconnect control module QD1, the first enable signal (SP enable signal) is enabled, 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 AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6 are forced to output a low level, and all drive signals connected to AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6 are invalid. When the SP enable signal is enabled, the SP enable signal is at a high level, and the pins of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6 connected to the SP enable signal are at a high level. The other input pins of AND gates B1, B3, B5, D2, D4, D6 are connected to the PWM1 drive signal, and the other input pins of AND gates B2, B4, B6, D1, D3, D5 are connected to the PWM2 drive signal. The output changes of 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 outputs of AND gates A1 and B1 are connected to the input pins of OR gate X1, the outputs of AND gates A2 and B2 are connected to the input pins of OR gate X2, the outputs of AND gates A3 and B3 are connected to the input pins of OR gate X3, the outputs of AND gates A4 and B4 are connected to the input pins of OR gate X4, the outputs of AND gates A5 and B5 are connected to the input pins of OR gate X5, the outputs of AND gates A6 and B6 are connected to the input pins of OR gate X6, the outputs of AND gates C1 and D1 are connected to the input pins of OR gate Y1, the outputs of AND gates C2 and D2 are connected to the input pins of OR gate Y2, the outputs of AND gates C3 and D3 are connected to the input pins of OR gate Y3, the outputs of AND gates C4 and D4 are connected to the input pins of OR gate Y4, the outputs of AND gates C5 and D5 are connected to the input pins of OR gate Y5, the outputs of AND gates C6 and D6 are connected to the input pins of OR gate Y6. When the outputs of AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6 are at a low level, the outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, Y6 change, which is the same as the output changes of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6, and is the same as the changes of the PWM drive signals connected to the pins of AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6.The outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, Y6 are respectively connected to drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, 62, and the drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, 62 respectively control silicon carbide MOSFET modules V11, V21, V31, V41, V51, V61, V12, V22, V32, V42, V52, V62. That is, the PWM1 drive signal controls silicon carbide MOSFET modules V11, V31, V51, V22, V42, V62, and the PWM2 drive signal controls silicon carbide MOSFET modules V21, V41, V61, V12, V32, V52, enabling the 12 silicon carbide MOSFET modules to achieve single-phase AC inversion.

[0065] For the working mode selection of the programmable drive interconnection control module QD1 in the SP mode, the first enable signal SP is enabled, and the second enable signal TP is disabled. The main circuit of the silicon carbide inverter includes 6 independent output connection points for single-phase AC inversion output. The 6 independent output connection points are divided into two output connection points for single-phase AC, and the 3 output connection points with the same electrical performance form the same output to achieve single-phase AC output and connect to the outside. Figure 1 Among them, A11, A12, and A13 have the same electrical performance. The 3 output connection points form the same output and are in parallel relationship, constituting one end of the single-phase AC output. B11, B12, and B13 have the same electrical performance. The 3 output connection points form the same output and are in parallel relationship, constituting the other end of the single-phase AC output.

[0066] Working mode 2 TP mode selection of the programmable drive interconnection control module QD1. The first enable signal SP is disabled, and the second enable signal TP 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, 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, D6 are invalid. When the TP enable signal is enabled, the TP enable signal is at a high level, and the pins of the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6 connected to the TP enable signal are at a high level. The other input pin of the AND gates A1 and C1 is connected to the PWM1 drive signal, the other input pin of the AND gates A2 and C2 is connected to the PWM2 drive signal, the other input pin of the AND gates A3 and C3 is connected to the PWM3 drive signal, the other input pin of the AND gates A4 and C4 is connected to the PWM4 drive signal, the other input pin of the AND gates A5 and C5 is connected to the PWM5 drive signal, and the other input pin of the AND gates A6 and C6 is connected to the PWM6 drive signal. The output changes of the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6 are the same as the changes of the PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 drive signals. The two outputs of the AND gates A1 and B1 are connected to the input pins of the OR gate X1, the two outputs of the AND gates A2 and B2 are connected to the input pins of the OR gate X2, the two outputs of the AND gates A3 and B3 are connected to the input pins of the OR gate X3, the two outputs of the AND gates A4 and B4 are connected to the input pins of the OR gate X4, the two outputs of the AND gates A5 and B5 are connected to the input pins of the OR gate X5, the two outputs of the AND gates A6 and B6 are connected to the input pins of the OR gate X6, the two outputs of the AND gates C1 and D1 are connected to the input pins of the OR gate Y1, the two outputs of the AND gates C2 and D2 are connected to the input pins of the OR gate Y2, the two outputs of the AND gates C3 and D3 are connected to the input pins of the OR gate Y3, the two outputs of the AND gates C4 and D4 are connected to the input pins of the OR gate Y4, the two outputs of the AND gates C5 and D5 are connected to the input pins of the OR gate Y5, and the two outputs of the AND gates C6 and D6 are connected to the input pins of the OR gate Y6. When the outputs of the AND gates B1, B2, B3, B4, B5, B6, D1, D2, D3, D4, D5, D6 are at a low level, the outputs of the OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, Y6 change, the same as the output changes of the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6, and the same as the changes of the PWM drive signals connected to the pins of the AND gates A1, A2, A3, A4, A5, A6, C1, C2, C3, C4, C5, C6.The outputs of OR gates X1, X2, X3, X4, X5, X6, Y1, Y2, Y3, Y4, Y5, Y6 are respectively connected to drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, 62. The drive circuits 11, 21, 31, 41, 51, 61, 12, 22, 32, 42, 52, 62 respectively control silicon carbide MOSFET modules V11, V21, V31, V41, V51, V61, V12, V22, V32, V42, V52, V62. That is, the PWM1 drive signal controls V11, V12, the PWM2 drive signal controls V21, V22, the PWM3 drive signal controls V31, V32, the PWM4 drive signal controls V41, V42, the PWM5 drive signal controls V51, V52, and the PWM6 drive signal controls V61, V62, enabling 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

[0067] For the working mode two TP mode selection of the programmable drive interconnection control module QD1, the first enable signal SP enable signal is prohibited, and the second enable signal TP enable signal is turned on. 6 independent output connection points are divided into three output connection points for three-phase AC, serving as the three-phase AC inversion output. 2 output connection points with the same electrical performance form the same output, achieving three-phase AC output and connecting to the outside. Figure 1 A11 and B11 have the same electrical performance. 2 output connection points form the same output, being in a parallel relationship, constituting the three-phase AC phase A output. A12 and B12 have the same electrical performance. 2 output connection points form the same output, being in a parallel relationship, constituting the three-phase AC phase B output. A13 and B13 have the same electrical performance. 2 output connection points form the same output, being in a parallel relationship, constituting the three-phase AC phase C output.

[0068] Embedded controller, including six PWM drive signal outputs PWM1, PWM2, PWM3, PWM4, PWM5, PWM6, and two enable signal outputs TP, SP. The drive connection circuit inside the programmable drive interconnection control module is selected through the two enable signal outputs TP, SP. When the two enable signal outputs TP, SP are both at low level or high level, 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 one, the two PWM drive signal outputs PWM1, PWM2 of the embedded controller are modulated according to the single-phase SPWM mode, and the first enable signal SP of the programmable drive interconnection control module is enabled, and the second enable signal TP is disabled, completing the working mode selection of the programmable drive interconnection control module. The two PWM drive signal outputs PWM1, PWM2 modulated by the single-phase SPWM control 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. In control mode two, the two PWM drive signal outputs PWM1, PWM2 of the embedded controller are modulated according to the high-frequency resonance alternating conduction mode, and the first enable signal SP of the programmable drive interconnection control module is enabled, and the second enable signal TP is disabled, completing the working mode selection of the programmable drive interconnection control module. The two PWM drive signal outputs PWM1, PWM2 modulated by the high-frequency resonance alternating conduction mode control 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. In control mode three, the six PWM drive signal outputs PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 of the embedded controller are modulated according to the three-phase SPWM mode, and the first enable signal SP of the programmable drive interconnection control module is disabled, and the second enable signal TP is enabled, completing the working mode selection of the programmable drive interconnection control module. The six SPWM drive signal outputs PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 modulated by the three-phase SPWM control 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

[0069] In control mode one, the PWM drive control is as Figure 3As shown, the PWM3, PWM4, PWM5, and PWM6 drive signals are at low level. The two PWM drive signals output PWM1 and PWM2, which 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 PWM1 and PWM2 modulated by single-phase SPWM control 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. AC1 is the single-phase AC output to be controlled, and VSAN is the triangular carrier wave. The AC1 with different frequencies and amplitudes is compared with the triangular carrier wave VSAN to generate the drive signals for the two silicon carbide MOSFET modules of PWM1 and PWM2 modulated in single-phase SPWM mode.

[0070] Control mode two, the PWM drive control is as Figure 4 As shown, the PWM3, PWM4, PWM5, and PWM6 drive signals are at low level. The two PWM drive signals output PWM1 and PWM2, which are modulated in 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. The PWM1 and PWM2 modulated in high-frequency resonance alternating conduction mode control 12 silicon carbide MOSFET modules to achieve single-phase AC inversion. In the high-frequency resonance alternating conduction mode, the PWM1 and PWM2 drive signals conduct alternately, and the pulse widths of PWM1 and PWM2 are greater than or equal to half of the resonance period. I1 is the high-frequency resonance current, that is, the pulse widths of PWM1 and PWM2 are greater than or equal to the time when the high-frequency resonance current I1 crosses zero.

[0071] Control mode three, the PWM drive control is as Figure 5As shown in the figure, the 6-channel PWM drive signals PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 are modulated in a 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-channel SPWM drive signals PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 output by three-phase SPWM modulation control 12 silicon carbide MOSFET modules to achieve three-phase AC inversion. A, B, and C are three-phase ACs that need to control the output phase difference of 120°. VSAN is a triangular carrier wave. The three-phase ACs of A, B, and C with different frequencies and amplitudes are compared with the same VSAN as the triangular carrier wave to generate 6-channel PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 silicon carbide MOSFET module drive signals modulated in a three-phase SPWM mode.

[0072] Embedded controller, such as Figure 7 As shown in the figure, the embedded controller is centered on a digital signal processor or a single-chip microcomputer. In addition to the output of 6-channel PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6 drive signals and the output of 2-channel TP and SP enable signals, it also includes multiple analog input AI1, AI2, AI3, AI4, AI5, AI6, AI7, AI8, multiple digital switch input DI1, DI2, DI3, DI4, DI5, DI6, multiple digital switch output DO1, DO2, DO3, DO4, DO5, DO6, and multiple communication ports COM1, COM2 to monitor the operating parameters of the high-voltage power supply such as input voltage, input current, output voltage, output current, and operating temperature, as well as feedback closed-loop control, which is convenient for upgrading and transforming other types of high-voltage power supplies.

[0073] Application of silicon carbide MOSFET inverter: With the same silicon carbide MOSFET inverter hardware, by changing the control mode through software, it can be used to transform the 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.

[0074] Specific application example 1 of a silicon carbide inverter and its control method: When the control mode of the silicon carbide inverter is mode 1, the schematic diagram of the transformation plan for replacing the single-phase thyristor regulation control circuit in the high-voltage power supply is as Figure 7As shown in the figure. Disconnect the connection between the single-phase thyristor regulating control circuit and the power frequency power distribution at the breakpoint, and disconnect the connection with the single-phase step-up rectifier transformer. The power input terminals A, B, and C of the silicon carbide inverter are connected to three-phase power frequency alternating current. In the figure, the single-phase step-up rectifier transformer and the connecting cables can be reused. The outputs A11, A12, and A13 of the silicon carbide inverter are connected to one end of the primary coil of the single-phase step-up rectifier transformer through cables, and the outputs B11, B12, and B13 of the silicon carbide inverter are connected to the other end of the primary coil of the single-phase step-up rectifier transformer through cables to complete the transformation. After the transformation of the silicon carbide inverter is realized, the regulating control is upgraded from a semi-controlled device to a fully-controlled device. When a high-voltage breakdown occurs in the high-voltage power supply, immediate turn-off protection can be realized. Compared with thyristor voltage regulation, the SPWM regulation method of the silicon carbide inverter can effectively suppress the generation of harmonics and reduce the pollution to the power grid. The SPWM voltage regulation technology of the 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 the silicon carbide inverter can accurately control the amplitude of the primary input voltage 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.

[0075] Specific application embodiment 2 of a silicon carbide inverter and its control method: When the control mode of the silicon carbide inverter is mode 2, the schematic diagram of the transformation scheme for replacing the IGBT control circuit in the high-voltage power supply is as Figure 8 shown in the figure. Disconnect the connection between the IGBT control circuit and the power frequency power distribution at the breakpoint, and disconnect the connection with the high-frequency step-up rectifier transformer. The power input terminals A, B, and C of the silicon carbide inverter are connected to three-phase power frequency alternating current. In the figure, the high-frequency step-up rectifier transformer and the connecting cables can be reused. The outputs A11, A12, and A13 of the silicon carbide inverter are connected to one end of the primary coil of the high-frequency step-up rectifier transformer through cables, and the outputs B11, B12, and B13 of the silicon carbide inverter are connected to the other end of the primary coil of the high-frequency step-up rectifier transformer through cables to complete the transformation. After the transformation of the silicon carbide inverter is realized, the regulating 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 operating frequency of the inverter. Increasing the frequency can reduce the core iron loss of the high-frequency rectifier transformer and improve the power supply efficiency.

[0076] Specific application embodiment 3 of a silicon carbide inverter and its control method: When the control mode of the silicon carbide inverter is mode 3, the schematic diagram of the transformation scheme for replacing the three-phase thyristor regulating control circuit in the high-voltage power supply. As Figure 9As shown in the figure. Disconnect the connection between the three-phase thyristor regulating control circuit and the power frequency power distribution at the breakpoint, and disconnect the connection with the three-phase step-up rectifier transformer. The power input terminals of the silicon carbide inverters A, B, and C are connected to three-phase industrial frequency alternating current. The three-phase step-up rectifier transformer and the connecting cables in the figure can be reused. The outputs A11 and B11 of the silicon carbide inverters are connected to the primary coil phase A of the three-phase step-up rectifier transformer through cables. The outputs A12 and B12 of the silicon carbide inverters are connected to the primary coil phase B of the three-phase step-up rectifier transformer through cables. The outputs A13 and B13 of the silicon carbide inverters are connected to the primary coil phase C of the three-phase step-up rectifier transformer through cables to complete the transformation. After the transformation of the silicon carbide inverter, the regulating control is upgraded from semi-controlled devices to fully-controlled devices. When a high-voltage breakdown occurs in the high-voltage power supply, immediate shutdown protection can be achieved. Compared with thyristor voltage regulation, the SPWM regulation method of the silicon carbide inverter can effectively suppress the generation of harmonics and reduce the pollution to the power grid. The SPWM voltage regulation technology of the 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 the silicon carbide inverter can accurately control the amplitude of the primary input voltage of the three-phase transformer, thereby accurately controlling the output voltage of the high-voltage power supply and enhancing the adaptability of the high-voltage power supply to working conditions.

[0077] Special statement: In this specification, "embodiments" and the like refer to the specific features, elements or characteristics described in connection with the embodiments being included in the embodiments generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. That is to say, when describing a specific feature, element or characteristic in connection with any embodiment, what is claimed is that the combination of other embodiments is used to implement that this feature, element or characteristic is included in the scope of the claims protected by this invention application; the embodiments are described with reference to multiple explanatory embodiments of the logic structure and ideas of this invention, but the protection scope of this 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 this invention, and can make various non-essential variations and improvements to the key points of the technical solution by changing the combination / or layout. For those skilled in the art, other uses will also be obvious, and non-substantive changes or replacements that can be easily implemented 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 power frequency AC power input connection point, a three-phase rectifier filter integrated with a 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 circuits 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 respectively: control mode one is modulated according to the single-phase SPWM mode to achieve single-phase AC inversion; control mode two is modulated according to the high-frequency resonance alternating conduction mode to achieve single-phase high-frequency AC inversion; control mode three is modulated according to the three-phase SPWM mode to achieve three-phase AC inversion; In the control of the programmable drive interconnection control module, a high-frequency drive control arithmetic formula of the silicon carbide MOSFET is calculated in combination with the working temperature factor of the silicon carbide MOSFET: Where: fw is the working 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 working temperature of the silicon carbide MOSFET, and Ta is the actual working temperature of the silicon carbide MOSFET.

2. The silicon carbide inverter according to claim 1, wherein Each of the two groups of silicon carbide MOSFET modules includes 6 silicon carbide MOSFET modules, and the 6 silicon carbide MOSFET modules respectively correspond to 6 drive circuits.

3. A 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, 2 enable signal inputs. The 12 PWM outputs are connected to the 12 drive circuits of the two groups of silicon carbide MOSFET modules. 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 the 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 the dynamic load tracking function, so as to improve the dynamic response speed and stability of the inverter through drive control; The automatic adaptation dead-time control algorithm is realized through the microcontroller MCU. According to the change of the load, the width of the dead time is adjusted in real time. The calculation formula of the dead time is: Td=(√2*π) / (3*Vs*Ls*(fs^2-fpwm^2)), where: Td is the dead time, Vs is the AC output voltage, Ls is the harmonic suppression inductor, fs is the switching frequency, and fpwm is the pulse width modulation frequency.

4. The silicon carbide inverter according to claim 3, wherein When the 2 enable signal inputs are at low level or high level, the programmable drive interconnection control module prohibits driving and controlling the two groups of silicon carbide MOSFET modules.

5. A silicon carbide inverter according to claim 4, characterized in that, The 2 enable signal inputs select the working mode. When the first enable signal is enabled, the 2 PWM drive signal inputs control the 12 PWM outputs to make the 12 silicon carbide MOSFET modules achieve single-phase AC inversion.

6. A silicon carbide inverter according to claim 4, characterized in that, The 2-channel enable signal input selects the working mode. When the second enable signal is enabled, the 6-channel PWM drive signal input controls the 12-channel PWM output, enabling 12 silicon carbide MOSFET modules to achieve three-phase AC inversion.

7. A silicon carbide inverter according to claim 1, characterized in that, The 6 independent output connection points change according to the 2-channel enable signal input of the 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 for single-phase AC. Three output connection points with the same electrical performance form the same output to achieve single-phase AC output and connect to the outside; when the second enable signal is enabled, the 6 independent output connection points are divided into three output connection points for three-phase AC. Two output connection points with the same electrical performance form the same output to achieve three-phase AC output and connect to the outside.

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

9. The silicon carbide inverter according to claim 8, characterized in that, The embedded controller uses a digital signal processor or a single-chip microcomputer as the core. In addition to the 6-channel PWM drive signal outputs and 2-channel enable signal outputs, it also includes multiple analog input channels, multiple digital switch input channels, multiple digital switch output channels, and multiple communication ports to monitor parameters such as the input voltage, input current, output voltage, output current, and operating temperature of the high-voltage power supply operation parameters, as well as feedback closed-loop control.

Images