Silicon carbide phase shift LLC type safety power supply

Abstract

The invention discloses a silicon carbide phase shift LLC type safety power supply, which comprises a double-gate relay module, an electronic switch H bridge module, a high-frequency transformation module, a bidirectional switch module, a low-pass filtering module, a detection loop reduction module and a power supply control module, and is characterized in that the input end of the double-gate relay module is used for inputting a direct current or alternating current power supply; the output end of the double-brake relay module is electrically connected with the electronic switch H-bridge module and the power supply control module, the output end of the electronic switch H-bridge module is electrically connected with the input end of the high-frequency voltage transformation module, and the output end of the high-frequency voltage transformation module is electrically connected with the bidirectional switch module. The output end of the bidirectional switch module outputs a restored power supply after passing through the low-pass filtering module and the detection loop restoring module; and the power supply control module is also electrically connected with the double-brake relay module, the electronic switch H bridge module, the high-frequency transformation module, the bidirectional switch module, the low-pass filtering module and the detection loop reduction module respectively.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuit breakers, and in particular to a silicon carbide phase-shift LLC type safety power supply. Background Art

[0002] In smart grids, electrical equipment failures, overloaded lines, overheating, and short circuits are often the root causes of electrical fires. Overheating and short circuits are the most common causes of electrical fires. Short circuits can be categorized as neutral-live short circuits or live-ground short circuits. Traditional circuit breakers and leakage protection devices, due to their long mechanical actuation times and slow response times, often produce large sparks at the moment of a short circuit. This is especially true when a circuit breaker's output line shorts to ground due to the ground's resistance. Furthermore, due to rusting of the ground wire over time, the ground resistance increases, leading to leakage currents, wasting energy, and potentially causing safety accidents. Traditional safety power supplies utilize isolation transformers. While these can provide one-to-one isolation of the power supply, effectively preventing leakage accidents, their inherent limitations include bulk, weight, high cost, and low efficiency. Furthermore, simple isolation transformers cannot extinguish arcs in the event of a load or line short circuit. Because transformers are made of silicon steel sheets and require a large amount of copper wire for the windings, their cost and size are extremely high. Full-voltage, high-frequency, direct-conversion, isolated safety power supplies using IGBTs are limited in key functions due to the IGBT's operating frequency and the module's internal conductive structure. This is reflected in the IGBT's difficulty exceeding 40kHz, which results in a larger high-frequency transformer. Due to the IGBT's internal PN junction architecture, the bidirectional electronic switch composed of the IGBT uses the IGBT's internal diode for freewheeling during any half-cycle. The IGBT's on-state voltage drop is relatively high, reaching approximately 1.9V-2.1V. Under high-frequency, high-power operation, its losses are extremely high. Because IGBT losses increase with frequency, and PN junction semiconductors can only conduct current in one direction, its inherent losses at several hundred amperes can reach several hundred watts, and combined with switching losses, this can even reach several kilowatts. The traditional IGBT isolated safety power supply adopts the phase-shift synchronization method of the previous stage for the rear-stage output. This method has the following defects: under light load power, the phase angle offset between the primary and secondary of the transformer is not very large. Under high power conditions, the primary and secondary of the transformer will produce a phase delay of 1-2 degrees because the hysteresis of the transformer increases with the increase of power. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a silicon carbide phase-shift LLC type safety power supply.

[0004] The object of the present invention is achieved through the following technical solutions: A silicon carbide phase-shift LLC type safety power supply, including: a dual-gate relay module, an electronic switch H-bridge module, a high-frequency transformer module, a bidirectional switch module, a low-pass filter module, a detection circuit restoration module and a power control module. The input end of the dual-gate relay module is used to input a DC or AC power supply, the output end of the dual-gate relay module is electrically connected to the electronic switch H-bridge module and the power control module respectively, the output end of the electronic switch H-bridge module is electrically connected to the input end of the high-frequency transformer module, the output end of the high-frequency transformer module is electrically connected to the bidirectional switch module, and the output end of the bidirectional switch module outputs the restored power supply after passing through the low-pass filter module and the detection loop restoration module; the power control module is also electrically connected to the dual-gate relay module, the electronic switch H-bridge module, the high-frequency transformer module, the bidirectional switch module, the low-pass filter module, and the detection loop restoration module respectively.

[0005] The advantages and beneficial effects of the present invention compared to the prior art are as follows: 1. The present invention is a silicon carbide phase-shifted LLC type safety power supply. By using silicon carbide high-frequency MOS as the main power switch, since the internal structure of the silicon carbide MOS is an N-type conductive channel structure, electron energy can flow bidirectionally. Therefore, under the condition of continuous current, the conduction voltage drop is only a few hundred millivolts, which greatly reduces the conduction loss, realizes the function of the isolation transformer for power frequency safety, and realizes the function of high-frequency and small-volume electrical isolation. Since the frequency can reach hundreds of kHz, the isolation transformer is more compact and has a greater cost advantage. At the same time, the LLC soft switching method is adopted, and its efficiency can reach more than 96%. The hysteresis of the high-frequency transformer is almost zero by using a synchronous coil to give a restored drive signal. The continuous current function of the bidirectional electronic switch of the subsequent stage restoration H bridge is then used to combine the functions of line or load short-circuit arc extinguishing to achieve the purpose of a truly safe power supply.

[0006] 2. The present invention is a silicon carbide phase-shifted LLC-type safety power supply, applicable to various power supply applications requiring electrical isolation. It can achieve AC-AC, DC-DC, square-wave-square-wave, triangle-wave-triangle, and any voltage source waveform requiring isolation. It utilizes a DSP or MCU phase-shifting method for closed-loop voltage stabilization, enabling stable voltage output in locations with large voltage fluctuations. It also incorporates a waveform correction function, controlling the phase shift angle to adjust the output power waveform in real time when the voltage waveform is non-standard. It can fundamentally replace isolated power-frequency transformers, achieving high-frequency operation. This overcomes the drawbacks of traditional IGBT-type isolated safety power supplies, such as high switching losses, inability to achieve arc extinguishing, and transformer hysteresis. The output includes an LC filter channel to filter out interference from grid harmonics that could affect equipment.

[0007] 3. The present invention is a silicon carbide phase-shifted LLC safety power supply. This high-frequency, isolated safety power supply utilizes silicon carbide (SiC) MOSFETs instead of IGBTs. In a sense, it can isolate and restore various voltage sources. It has no strict requirements for the input voltage source. It is a transition from the original full-voltage, high-frequency, direct-conversion, isolated safety power supply. By replacing the IGBT with a SiC MOSFET, the original pulse-synchronized post-reduction method has been changed to a transformer secondary-synchronized square wave method, and the original hard switching method has been upgraded to an LLC soft-switching method. This fundamentally changes its operating mode, increasing frequency, reducing losses, reducing size, and saving costs. It has broad application in the fields of new energy and safe electricity use. Furthermore, by changing the post-reduction method and utilizing the freewheeling function of the post-stage four-quadrant power bridge, it combines the short-circuit arc extinguishing functions into one, resulting in a safe power supply device that provides both output power to the load and output line short-circuit arc extinguishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a functional principle diagram of a silicon carbide phase-shifted LLC type safety power supply according to one embodiment of the present invention; Figure 2 This is the circuit schematic diagram of the IGBT switch of the traditional IGBT safety power supply; Figure 3 This is a circuit diagram of the electronic switch H-bridge module of the silicon carbide phase-shifted LLC type safety power supply of the present invention; Figure 4 This is the circuit schematic diagram of a traditional IGBT safety power supply; Figure 5 This is the phase-shift drive waveform of the traditional IGBT safety power supply; Figure 6 The circuit schematic diagram of the electronic switch H-bridge module and the bidirectional switch module of the present invention; Figure 7This is a phase-shift driving waveform diagram of the silicon carbide phase-shift LLC type safety power supply of the present invention; Figure 8 This is a DC input drive timing diagram of the safety power supply of the present invention; Figure 9 This is a timing diagram of the DC transformer output of the safety power supply of the present invention; Figure 10 This is the AC positive half-cycle input diagram of the safety power supply of the present invention; Figure 11 This is the AC negative half-cycle input diagram of the safety power supply of the present invention; Figure 12 This is an AC output timing diagram of the safety power supply of the present invention; Figure 13 This is the AC filter output waveform diagram of the present invention; Figure 14 This is a working principle diagram of the silicon carbide phase-shifted LLC type safety power supply of the present invention after short-circuit arc extinguishing; Figure 15 This is a circuit diagram of the undervoltage circuit of the driving part of the silicon carbide phase-shift LLC type safety power supply of the present invention; Figure 16 This is a circuit diagram of the positive and negative half-cycle modulation circuit of the silicon carbide phase-shifted LLC type safety power supply of the present invention; Figure 17 This is a circuit diagram of a synchronous square wave modulation circuit of a silicon carbide phase-shifted LLC type safety power supply of the present invention; Figure 18 A circuit diagram of a positive half-cycle fundamental wave driving circuit and a negative half-axis modulated wave driving circuit of the present invention; Figure 19 1 is a circuit diagram of a front-stage negative half-cycle modulation wave driving circuit of the present invention; Figure 20 A circuit diagram of a synchronous pulse drive signal driving circuit of the present invention; Figure 21 A circuit diagram of the main processor MCU of the power control module of the present invention; Figure 22 is a circuit diagram of the phase-shift drive processing unit of the present invention; Figure 23 This is a functional principle diagram of a silicon carbide phase-shifted LLC type safety power supply according to another embodiment of the present invention. DETAILED DESCRIPTION

[0009] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0010] This invention is a device designed to prevent safety incidents caused by electrical equipment failures or electrical circuit short circuits or grounding. Its ultimate goal is to prevent electrical fires, firefighting incidents, leakage accidents, electric shock injuries, and other life and property safety hazards. It is an improved and upgraded version of the IGBT isolated safety power supply. Instead of the phase-shifted hard switching method of the original IGBT isolated safety power supply, it employs phase-shifted LLC soft-switching technology to fundamentally address the harmful effects of voltage stress on the switching tube. It also uses synchronous windings to provide drive signals, replacing the original drive signals provided by the phase-shift angle, thus addressing the hysteresis effect. The parallel voltage insulation detection method provides more accurate online resistance detection for the line. The freewheeling function of the subsequent H-bridge is utilized to add short-circuit arc extinguishing and fault arc detection capabilities.

[0011] See also Figures 1 to 22 This silicon carbide phase-shifted LLC safety power supply, also known as the silicon carbide A / A phase-shifted LLC safety power supply, uses silicon carbide MOSFETs as the main power switching components. It employs a common-S drain configuration, with two MOSFETs forming a bidirectional electronic switch for bidirectional current movement. Eight sets of bidirectional electronic switches (16 in total) form a phase-shifted full-bridge architecture between the front and rear stages, achieving voltage reduction and isolation. This makes it suitable for research environments requiring high power quality, such as the isolated power supply required by laboratories, for experimental research and development. It is often used in low-voltage IT power distribution systems as a secondary isolated power supply for industrial, commercial, and civil power distribution. It can also be used as a power supply requiring DC isolation in new energy DC power supplies. When used in industrial and civilian power distribution systems, it can isolate and correct the 220V mains power supply in a one-to-one ratio. This ensures that the 220V power output from the SiC A / A Phase-Shift LLC safety power supply is no longer connected to the mains, preventing electric shock injuries to humans or living organisms if they come into contact with the neutral or live wire. The SiC A / A Phase-Shift LLC safety power supply also uses parallel voltage insulation detection to monitor residual current and leakage current in the output power supply in real time. If leakage current increases due to contact with a live object, the SiC A / A Phase-Shift LLC safety power supply automatically disconnects the output power supply to ensure personal safety. Furthermore, the H-bridge composed of eight sets of bidirectional electronic switches in the downstream stage synchronously restores the high-frequency four-quadrant pulse signal during normal operation. In the event of a short-circuit arc extinguishing, the upper four sets of bidirectional electronic switches are closed, while the lower four sets are open, confining the short-circuit current to the LC resonant cavity.

[0012] The silicon carbide A / A phase-shifted LLC safety power supply replaces the bulky, heavy, and expensive traditional power-frequency transformers. It also upgrades and improves upon the IGBT-based isolated safety power supply, overcoming the low frequency and high conduction losses of these devices. Its high frequency and low losses make it suitable for use in residential power distribution systems. In commercial applications, it can be used in shopping malls, shops, office buildings, residential buildings, hospitals, schools, government agencies, banks, and fire protection systems. In industrial applications, it can be used in power distribution systems or smart grids in mining, metallurgy, factories, and other sectors.

[0013] See also Figure 1 A silicon carbide phase-shifted LLC safety power supply comprises a dual-gate relay module, an electronic switch H-bridge module, a high-frequency transformer module, a bidirectional switch module, a low-pass filter module, a detection circuit restoration module, and a power control module. Preferably, the power control module is an MCU or DSP processor. In this embodiment, the high-frequency transformer module uses a synchronous secondary winding to eliminate voltage spikes caused by transformer hysteresis under high load conditions.

[0014] The input end of the dual-gate relay module is used to input a DC or AC power supply, the output end of the dual-gate relay module is electrically connected to the electronic switch H-bridge module and the power control module respectively, the output end of the electronic switch H-bridge module is electrically connected to the input end of the high-frequency transformer module, the output end of the high-frequency transformer module is electrically connected to the bidirectional switch module, and the output end of the bidirectional switch module outputs the restored power supply after passing through the low-pass filter module and the detection loop restoration module; the power control module is also electrically connected to the dual-gate relay module, the electronic switch H-bridge module, the high-frequency transformer module, the bidirectional switch module, the low-pass filter module, and the detection loop restoration module respectively.

[0015] It's important to note that the dual-gate relay module's input can be flexibly connected to a DC or AC power source or smart grid, providing stable power input for the entire power system. The module's output is electrically connected to the electronic switch H-bridge module and the power control module. This module transmits input power to the electronic switch H-bridge module, providing the energy foundation for subsequent power conversion. Furthermore, the connection to the power control module enables real-time monitoring and control of the dual-gate relay module's operating status, such as promptly shutting off input in the event of a power anomaly, ensuring system safety.

[0016] Thus, by using silicon carbide (SiC) MOS tubes instead of IGBTs, a high-frequency isolated safety power supply can, in a sense, isolate and restore various voltage sources. There are no strict requirements for the input voltage source. It is a transformation of the original full-voltage high-frequency direct conversion isolated safety power supply. The SiC MOS tube replaces the IGBT, the original pulse synchronous post-polarity restoration method is changed to a transformer secondary synchronous square wave method, and the original hard switching method is upgraded to LLC soft switching. This fundamentally changes its operating mode, increases frequency, reduces losses, reduces size, and saves costs. It can be widely used in the fields of new energy and safe electricity use. At the same time, it changes the post-stage restoration method and utilizes the freewheeling function of the post-stage four-quadrant power bridge to combine the short-circuit arc extinguishing functions into one, making it a safe power supply device with both safe power output load and output line short-circuit arc extinguishing.

[0017] See also Figure 3 The electronic switch H-bridge module includes four silicon carbide MOS switch groups and a resonant capacitor C1. The four silicon carbide MOS switch groups are connected end to end to form an H-bridge. The first end of the resonant capacitor C1 is connected to the output end of one of the silicon carbide MOS switch groups, and the second end of the resonant capacitor C1 is electrically connected to the high-frequency transformer module. Preferably, in one of the silicon carbide MOS switch groups, the silicon carbide MOS switch group includes two silicon carbide MOS electronic switches connected in series. It should be noted that the output end of the electronic switch H-bridge module is connected to the input end of the high-frequency transformer module, transmitting the converted electrical energy to the high-frequency transformer module. The electronic switch H-bridge module is mainly composed of four silicon carbide MOS switch groups and a resonant capacitor C1. The four silicon carbide MOS switch groups are connected end to end to form an H-bridge structure. This structural design can efficiently achieve electrical energy conversion. Each SiC MOS switch group comprises two SiC MOS electronic switches connected in series. In this embodiment, the four SiC MOS switch groups are MOS K1 and MOS K2, MOS K3 and MOS K4, MOS K5 and MOS K6, and MOS K7 and MOS K8. SiC MOS electronic switches feature low on-resistance and high switching speed, significantly reducing energy loss during power conversion. Resonant capacitor C1 has one end connected to the output of one of the SiC MOS switch groups and the other end connected to the high-frequency transformer module. It stabilizes voltage and regulates current in the circuit, working in conjunction with the SiC MOS switch group to ensure the quality of the power input to the high-frequency transformer module.

[0018] See also Figure 6The bidirectional switch module includes four bidirectional electronic switch groups, which are sequentially connected end to end to form an H-bridge. The input end of one of the bidirectional electronic switch groups is electrically connected to the high-frequency transformer module, and the output end of another bidirectional electronic switch group is electrically connected to the low-pass filter module. The control ends of the four bidirectional electronic switch groups are also electrically connected to the power control module. Preferably, in one of the bidirectional electronic switch groups, the bidirectional electronic switch group includes two silicon carbide MOS tube switches connected in series. It should be noted that the output end of the bidirectional switch module is connected to the low-pass filter module to transmit the processed electrical energy to the low-pass filter module. The bidirectional switch module is composed of four bidirectional electronic switch groups, which are sequentially connected end to end to form an H-bridge structure. In this embodiment, the four silicon carbide MOS switch groups are switch group KZ1, switch group KZ2, switch group KZ3, and switch group KZ4. Each bidirectional electronic switch group consists of two silicon carbide MOS switches connected in series. The excellent performance of silicon carbide MOS switches ensures that the bidirectional switch modules can quickly and stably transmit power in both directions. The control terminals of the bidirectional switch modules are connected to the power control module. The power control module precisely controls the on and off states of the bidirectional electronic switch groups based on actual system requirements, thereby achieving bidirectional power transmission and flexible adjustment of the output voltage and current.

[0019] See also Figure 6 The low-pass filter module includes an inductor L1 and a capacitor C2. One end of the inductor L1 is electrically connected to one end of the bidirectional switch module, and the other end of the inductor L1 is electrically connected to the capacitor C2. It should be noted that the low-pass filter module is composed of the inductor L1 and the capacitor C2. One end of the inductor L1 is connected to the output end of the bidirectional switch module to receive electrical energy from the bidirectional switch module, and the other end is connected to the capacitor C2. The main function of the low-pass filter module is to filter the electrical energy, remove high-frequency interference signals, make the output electrical energy purer and more stable, and provide high-quality electrical energy input for the subsequent detection circuit recovery module.

[0020] It's also important to note that the detection loop restoration module is the "last line of defense" for the entire power system. It receives power from the low-pass filter module, performs further detection and processing, and ultimately outputs restored power, providing a stable and reliable power supply to the load. The power control module, serving as the control center for the entire power system, establishes electrical connections with the dual-gate relay module, electronic switch H-bridge module, high-frequency transformer module, bidirectional switch module, low-pass filter module, and detection loop restoration module. It monitors the operating status of each module in real time and, based on the system's operating conditions and pre-set control strategies, precisely controls and adjusts each module to ensure coordinated and stable operation of the entire power system.

[0021] While working, see Figure 1 、 Figure 3 、 Figure 6 and Figure 23 After passing through circuit breaker Q1, the power supply enters the input of relay KM1 / relay KM2. Relay KM1 / relay KM2 splits the power supply into two paths: one path enters an H-bridge composed of bidirectional electronic switches, and the other path is sent to the input power detection unit, which sends the DC or AC source signal to the DSP processor for processing. When the input is a DC source, MOS K3 / MOS K4 / MOS K7 / MOS K8 of the electronic switch H-bridge module will turn on, and MOS K1 / MOS K2 / MOS K5 / MOS K6 of the electronic switch H-bridge module will perform phase-shift pulse modulation. When the input is an AC source and the input is in the positive half-cycle, MOS K3 / MOS K4 / MOS K7 / MOS K8 of the electronic switch H-bridge module will be a 50Hz fundamental wave, and MOS K1 / MOS K2 / MOS K5 / MOS K6 of the electronic switch H-bridge module will be a phase-shift modulated carrier. When the input is an AC source and is in the negative half-cycle, MOS K1 / MOS K2 / MOS K5 / MOS K6 of the electronic switch H-bridge module generate a 50Hz fundamental wave, while MOS K3 / MOS K4 / MOS K7 / MOS K8 of the electronic switch H-bridge module generate a phase-shifted modulated carrier wave. This, through resonant capacitor C1, forms a four-quadrant high-frequency pulse wave on the primary side of the high-frequency transformer. Transformer T1's secondary winding induces the high-frequency pulse power from the primary winding and transmits this power to the subsequent bidirectional switch module's switch groups KZ1 / KZ2 / KZ3 / KZ4 for decompression. The synchronous windings amplify the four-quadrant high-frequency pulse power and transmit it to the synchronous pulse decompression processor. When transformer T1 is not operating, switch groups KZ1 / KZ2 / KZ3 / KZ4 are fully open. When the pulse voltage signal comes, the positive pulse closes the switch group KZ1 / switch group KZ4, and the negative pulse closes the switch group KZ2 / switch group KZ3. Then the AC high-frequency pulse signal is sent to the low-pass filter composed of inductor L1 / capacitor C2 to remove the high-frequency signal and restore it to AC power supply. The restored power supply passes through the output current detection unit and the leakage current detection unit, and is sent to the output voltage detection unit and the fault arc detection unit, and then passes through the parallel voltage insulation detection unit and the waveform correction unit before being output.

[0022] See also Figure 2In a traditional IGBT safety power supply, when the power input is the positive half cycle of the AC power, the fundamental wave signal is input to K2 / K4 / K6 / K8. However, due to the PN junction structure inside the IGBT, the fundamental wave drive signal is invalid for the K2 / K4 / K6 / K8 group. The current can only pass through the body diodes of K2 / K4 / K6 / K8. However, due to the tube voltage drop of the body diodes, the conduction loss is very high. At the same time, since the bidirectional bridge is a hard switching structure, the front-stage input requires L1 / C1 inductors and capacitors to filter out the interference signals caused by the switching tube.

[0023] See also Figure 3 In the SiC A / A phase-shifted LLC safety power supply of the present invention, when an AC positive half-cycle signal is input to SiC MOS MOSFETs K3 / K4 / K7 / K8, because SiC MOS MOSFETs do not have a PN junction structure, part of the current flows through the body diodes of SiC MOS MOSFETs K3 / K4 / K7 / K8, while the remaining current flows through the conductive channel to the high-frequency transformer. Due to the extremely low internal resistance of SiC MOS MOSFETs, the current loss through SiC MOS MOSFETs K3 / K4 / K7 / K8 is negligible. Furthermore, because C1 is a resonant capacitor, the current flows through capacitor C1 and the leakage inductance of transformer T1 to form an LC resonant cavity, forming a soft switch, eliminating the need for input inductors and capacitors.

[0024] See also Figure 4~Figure 5 The traditional IGBT isolated safety power supply uses the front-stage synchronous pulse to send to the back-stage as a restoration drive. Due to the hysteresis of the transformer, under high load conditions, it will bring a huge spike voltage to the switching tube IGBT, causing IGBT breakdown and other accidents.

[0025] See also Figure 6-7 The silicon carbide phase-shifted LLC safety power supply of the present invention adopts a secondary winding synchronous coil operation mode, effectively eliminating the switching tube loss caused by hysteresis in the transformer, effectively protecting the working state of the silicon carbide MOS, and simplifying the working mode of the drive module.

[0026] See also Figures 8 and 9When the SiC phase-shift LLC safety power input is DC, the synchronous actuator does not need to detect the zero-crossing signal. The drive controller will lock the SiC MOS K3 / MOS K4 / MOS K7 / MOS K8 in a high-level conduction state, and the SiC MOS K1 / MOS K2 / MOS K5MOS / K6 will perform phase shift adjustment control. The conduction process is that SiC MOS K1 turns on first and reaches 50%. Then SiC MOS K6 turns on the current to charge capacitor C1. The charging direction is positive on the left and negative on the right. On the one hand, the current charges the capacitor C1, and on the other hand, it provides energy to the primary winding of the transformer T1. When the silicon carbide MOS K1 is 100% open and half-closed and enters the dead time, the silicon carbide MOS K5 is turned on. The current of the capacitor C1 charges the junction capacitance of the silicon carbide MOS K1 on the one hand, and on the other hand, it supplies power to the transformer T1 winding through the silicon carbide MOS K5. Due to the leakage inductance and initial inductance of the transformer T1, the current curve rises slowly. When the capacitor C1 is fully replenished, the current is basically zero, and K1 realizes zero current shutdown ZCS. Due to the junction capacitance of the silicon carbide MOS K5, the capacitor C5 must charge the junction capacitance of the silicon carbide MOS K5 before the silicon carbide MOS K5 is turned on, realizing the zero voltage turn-on ZVS of the silicon carbide MOS K5.

[0027] See also Figure 9 The secondary side of the high-frequency transformer in the silicon carbide phase-shifted LLC safety power supply outputs an alternating square wave pulse signal, which is commutated by the synchronous winding, which controls four bidirectional switch groups. When there's no voltage signal on the high-frequency transformer's secondary winding, the four bidirectional electronic switch groups (KZ1, KZ2, KZ3, and KZ4) remain on. When an alternating square wave pulse signal arrives, the synchronous winding controls the corresponding switch groups to close, and the voltage signal is output by the remaining switch groups. When the transformer is in the positive position at the top and the negative position at the bottom, the positive synchronous pulse controls switch groups KZ2 and KZ3, shutting off the current flowing through switch groups KZ1 and KZ4. When the transformer is in the positive position at the bottom and the negative position at the top, the negative synchronous pulse controls switch groups KZ1 and KZ4, shutting off the current flowing through switch groups KZ2 and KZ3.

[0028] See also Figure 10 and Figure 11When the silicon carbide phase-shift LLC safety power supply input is AC, in the positive half cycle of AC, silicon carbide MOS K3 / MOS K4 / MOS K7 / MOS K8 are synchronous fundamental wave signals with the same frequency as the input power frequency, and silicon carbide MOS K1 / MOS K2 / MOS K5 / MOS K6 are phase-shifted carrier signals. Its input method is almost the same as that of DC input. When the input is the negative half cycle of AC, silicon carbide MOS K1 / MOS K2 / MOS K4 / MOS K6 are synchronous fundamental wave signals with the same frequency as the input power frequency, and silicon carbide MOS K3 / MOS K4 / MOS K7 / MOS K8 are phase-shifted carrier signals.

[0029] See also Figure 12-13 The secondary winding of the high-frequency transformer outputs a four-quadrant alternating pulse signal, which splits the two half-cycle signals into four pulse signals. At this time, the post-stage restoration bidirectional electronic switch group works alternately to restore the four-quadrant pulse signal into an AC pulse power supply, and the required voltage waveform is obtained after passing through the LC low-pass filter.

[0030] See also Figure 14 When the output power of the silicon carbide phase-shifted LLC safety power supply is short-circuited or a short-circuit bridge fault occurs in the load equipment and requires arc extinguishing, switch group KZ1 / switch group KZ2 / switch group KZ3 / switch group KZ4 are turned on at the same time, and the remaining current is consumed in the inductor L1 and capacitor C2 in an LC resonance manner.

[0031] See also Figure 15 and Figure 16 The power control module includes an undervoltage circuit and a positive and negative half-cycle modulation circuit. The undervoltage circuit is used to connect to the mains power, and the output end of the undervoltage circuit is electrically connected to the positive and negative half-cycle modulation circuit. Specifically, the undervoltage circuit includes a rectifier chip U3, an optocoupler U4, a MOS tube U1, and peripheral electronic components. When the power is input from the interface terminal J1, it is input to the rectifier chip U3 through the resistor R2 for rectification, and then filtered by the capacitor C3. It is clamped by the resistor R1 and the diode D2 and sent to the optocoupler U4. When the input power is normal, the MOS tube U1 turns on the positive and negative half-cycle modulation circuit to work.

[0032] The positive and negative half-cycle modulation circuit includes a comparator U7A, a transistor Q3, a comparator U7B, and a transistor Q2. The power input is divided by resistors R14, R15, R21, and R23 before being sent to comparator U7A. When the input power is a DC power source, comparator U7A operates continuously. When the input power is an AC power source, comparator U7A and comparator U7B operate alternately, and resistors R6 and R8 form a comparison voltage, creating a dead time between the positive and negative half-cycles.

[0033] See also Figure 17 , the power control module also includes a synchronous square wave modulation circuit, the power input end of the synchronous square wave modulation circuit is electrically connected to the undervoltage circuit and the positive and negative half-cycle modulation circuit respectively, and the control end of the synchronous square wave modulation circuit is electrically connected to the main processor MCU. The synchronous square wave modulation circuit includes an optocoupler U8, an optocoupler U9, a transistor Q1, a transistor Q4, a transistor Q6, and a transistor Q7. Among them, the synchronous square wave modulation signal Q+ / Q- can drive the optocoupler U8 / optocoupler U9, and form fundamental wave drive signals +PWM and -PWM through transistors Q1 / transistor Q4 / transistor Q6 / transistor Q7 and resistors R25 / resistor R26 / resistor R28 / resistor R29 / resistor R33 / resistor R34 / resistor R40 / resistor R39. When the input is a DC power supply DC, only +PWM works. If the input is an AC signal, +PWM and -PWM work alternately.

[0034] See also Figure 18 and Figure 19 The power control module also includes a positive half-cycle fundamental wave drive circuit and a negative half-axis modulated wave drive circuit. The drive control terminals of the positive half-cycle fundamental wave drive circuit and the negative half-axis modulated wave drive circuit are respectively electrically connected to the main processor MCU. The output terminals of the positive half-cycle fundamental wave drive circuit are respectively electrically connected to the control terminals of four MOS transistors in the electronic switch H-bridge module, and the output terminals of the negative half-axis modulated wave drive circuit are respectively electrically connected to the control terminals of the other four MOS transistors in the electronic switch H-bridge module. Among them, the +PWM and -PWM signals are divided into two groups of identical drive circuits, which are respectively combined with the phase-shifted modulation signal and drive the silicon carbide MOS K1-K8 with the eight groups of drive signals K1-K8. PWMA-PWMD are phase-shifted drive signals. When the +PWM is in the positive half-cycle, U1A-U1D are in operation, synthesizing the fundamental wave signal and the modulated signal into a drive signal for output. When the -PWM is in the negative half-cycle, U6A-U6D are in operation, synthesizing the fundamental wave signal and the modulated signal into a drive signal for output. When the DC power supply is input, only the +PWM / U1A-U1D are in operation. See also Figure 20The power control module also includes a synchronous pulse post-stage drive circuit. The input of the synchronous pulse post-stage drive circuit is connected to the high-frequency transformer T1 and the main processor MCU, and the output of the synchronous pulse post-stage drive circuit is electrically connected to the four silicon carbide MOS switch groups. The synchronous pulse post-stage drive circuit includes chip U4A, chip U4B, transistors Q17, transistor Q4, transistor Q18, and transistor Q10. The synchronous pulse drive signal obtained from the high-frequency transformer's synchronous coil is sent to terminal A of chip U4A and terminal C of chip U4B, while the control signal sent by the main processor MCU is sent to terminal B of chip U4A and terminal D of chip U4B. When the main processor MCU sends a drive signal to PPA / PPB, transistors Q17, transistor Q4, transistor Q18, and transistor Q10 alternately operate. When the output is short-circuited or arc extinguishing is required, PPA / PPB are directly turned off, and switch groups KZ1-KZ4 operate directly.

[0035] See also Figure 21 and Figure 22 The power control module also includes a main processor MCU and a phase-shift drive processing unit. The main processor MCU and the phase-shift drive processing unit are electrically connected, and the phase-shift drive processing unit is electrically connected to the silicon carbide MOS MOSFETs K1-K8 of the electronic switch H-bridge module. The main processor MCU is composed of chip U1, which is responsible for processing analog and digital signals sent from various chips. The phase-shift drive processing unit's phase-shift drive signal is generated by chip U2, which is responsible for providing the phase-shift drive signal to the driver.

[0036] The present invention changes the problem that the frequency of the traditional IGBT isolated safety power supply is not high enough and the freewheeling diode is required to generate large losses. At the same time, the hard switching mode of the traditional IGBT is changed. The operating frequency is increased, the size of the transformer can be smaller, the LLC soft switching mode is added, and the working environment of the bidirectional electronic switch is improved. The LC inductor and capacitor required in the front stage are eliminated. The cost is saved, and the short-circuit arc extinguishing function is added by utilizing the reverse shutdown function of the back stage. The copper wire of the transformer winding is reduced, and the existence of distributed capacitance is reduced. The voltage level is improved and can be applied to DC, AC square waves, or voltages of arbitrary waveforms. It is more practical in the field of new energy.

[0037] The above-described embodiments merely represent several embodiments of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A silicon carbide phase-shift LLC type safety power supply, characterized in that: include: Dual-gate relay module, electronic switch H-bridge module, high-frequency transformer module, bidirectional switch module, low-pass filter module, detection circuit restoration module and power control module, The input end of the dual-gate relay module is used to input a DC or AC power supply, the output end of the dual-gate relay module is electrically connected to the electronic switch H-bridge module and the power control module respectively, the output end of the electronic switch H-bridge module is electrically connected to the input end of the high-frequency transformer module, the output end of the high-frequency transformer module is electrically connected to the bidirectional switch module, and the output end of the bidirectional switch module outputs the restored power supply after passing through the low-pass filter module and the detection loop restoration module; the power control module is also electrically connected to the dual-gate relay module, the electronic switch H-bridge module, the high-frequency transformer module, the bidirectional switch module, the low-pass filter module, and the detection loop restoration module respectively.

2. The silicon carbide phase-shift LLC type safety power supply according to claim 1, characterized in that: The electronic switch H-bridge module includes four silicon carbide MOS switch groups and a resonant capacitor C1. The four silicon carbide MOS switch groups are connected end to end to form an H-bridge. The first end of the resonant capacitor C1 is connected to the output end of one of the silicon carbide MOS switch groups, and the second end of the resonant capacitor C1 is electrically connected to the high-frequency transformer module.

3. The silicon carbide phase-shift LLC type safety power supply according to claim 2, characterized in that: In one of the silicon carbide MOS switch groups, the silicon carbide MOS switch group includes two silicon carbide MOS electronic switches connected in series.

4. The silicon carbide phase-shift LLC type safety power supply according to claim 1, characterized in that: The high-frequency transformer module adopts a secondary winding synchronous coil working mode to eliminate the peak voltage caused by the hysteresis of the transformer under high load conditions.

5. The silicon carbide phase-shift LLC type safety power supply according to claim 1, characterized in that: The bidirectional switch module includes four bidirectional electronic switch groups, which are sequentially connected to form an H-bridge. The input end of one of the bidirectional electronic switch groups is electrically connected to the high-frequency transformer module, and the output end of another bidirectional electronic switch group is electrically connected to the low-pass filter module. The control ends of the four bidirectional electronic switch groups are also electrically connected to the power control module.

6. The silicon carbide phase-shift LLC type safety power supply according to claim 5, characterized in that: In one of the bidirectional electronic switch groups, the bidirectional electronic switch group includes two silicon carbide MOS transistor switches connected in series.

7. The silicon carbide phase-shift LLC type safety power supply according to claim 1, characterized in that: The low-pass filter module includes an inductor L1 and a capacitor C2. One end of the inductor L1 is electrically connected to one end of the bidirectional switch module, and the other end of the inductor L1 is electrically connected to the capacitor C2.

8. The silicon carbide phase-shift LLC type safety power supply according to claim 7, characterized in that: The power control module is an MCU processor or a DSP processor.

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