Silicon carbide MOS transformer drive circuit and welding machine

Abstract

The invention discloses a silicon carbide MOS transformer driving circuit and a welding machine, the silicon carbide MOS transformer driving circuit comprises a driving unit, the driving unit comprises a first driving module, and the first driving module comprises a first control end and a first conduction end; the driving transformation unit comprises a first connecting end and a second connecting end, and the first connecting end and the second connecting end are electrically connected with the first driving module respectively; the switch unit is electrically connected with the first control end and the first conduction end respectively; wherein the driving transformation unit generates forward voltage and transmits the forward voltage to the first driving module through the first connecting end, and the first driving module controls the switch unit to be switched on based on the forward voltage; when the driving transformation unit is in a dead zone state, the first driving module generates a first negative voltage to drive the switch unit to be switched off; and the driving transformation unit generates a second negative voltage and transmits the second negative voltage to the first driving module through the second connecting end, so that the second negative voltage is superposed with the first negative voltage to control the switch unit to be in a deep cut-off state.

Description

Technical Field

[0001] The present invention relates to the technical field of welding machines, and in particular to a silicon carbide MOS transformer driving circuit and a welding machine. Background Art

[0002] Since its introduction, silicon carbide (SiC) MOS devices have been widely used in the field of power electronics due to their excellent performance advantages. Silicon carbide MOS has the characteristics of fast switching speed, high junction temperature, and high efficiency, which enables it to develop rapidly in high-frequency, high-temperature, and high-efficiency power conversion applications. However, in order to give full play to the performance of silicon carbide MOS devices, its drive circuit needs to provide a positive drive voltage of +18V to +20V and a negative drive voltage of -4V to -8V, which places high demands on the design of the drive circuit.

[0003] Currently, the main implementation methods for driving SiC MOS devices on the market are mostly isolation driver chip solutions. These solutions include optical isolation driver chips, magnetic isolation driver chips, and capacitive isolation driver chips. The isolation driver chip solution provides isolation voltage to the driver chip through an auxiliary power supply to achieve the positive and negative drive voltages required by SiC MOS devices.

[0004] However, since the existing technology requires multiple sets of auxiliary power supply support, whether it is a full-bridge, half-bridge or dual-tube single-ended forward solution, the increase in the number of auxiliary power supplies will make the overall circuit design complicated and increase the difficulty of system design and debugging. Summary of the invention

[0005] The main purpose of the present invention is to provide a silicon carbide MOS transformer driving circuit, aiming to solve the problem of complex design of silicon carbide MOS driving circuit.

[0006] To achieve the above object, the present invention provides a silicon carbide MOS transformer driving circuit, comprising:

[0007] A driving unit, the driving unit comprising a first driving module, the first driving module comprising a first control end and a first conduction end;

[0008] A driving transformer unit, the driving transformer unit comprising a first connecting end and a second connecting end, the first connecting end and the second connecting end being electrically connected to the first driving module respectively;

[0009] a switch unit, the switch unit being electrically connected to the first control end and the first conduction end respectively;

[0010] The driving transformer unit generates a forward voltage and transmits it to the first driving module through the first connecting end, and the first driving module controls the switch unit to conduct based on the forward voltage;

[0011] The driving transformer unit is in a dead zone state, and the first driving module generates a first negative voltage to drive the switch unit to turn off;

[0012] The driving transformer unit generates a second negative voltage and transmits it to the first driving module through the second connecting terminal, so as to be superimposed with the first negative voltage to control the switch unit to be in a deep cut-off state.

[0013] In some embodiments, the first driving module includes:

[0014] A negative voltage generating circuit, wherein the negative voltage generating circuit is electrically connected to the first connection terminal and the second connection terminal respectively, and the negative voltage generating circuit comprises a first output terminal and a second output terminal; the first output terminal is electrically connected to the first control terminal, and the second output terminal is electrically connected to the first conduction terminal;

[0015] The switch unit includes a first switch tube, a gate of the first switch tube is electrically connected to the first control end, a source of the first switch tube is electrically connected to the first conduction end, and a drain of the first switch tube is electrically connected to a power supply.

[0016] In some embodiments, the negative voltage generating circuit comprises:

[0017] A one-way conductive member, wherein an anode of the one-way conductive member is electrically connected to the first connection end;

[0018] A voltage stabilizer, wherein a cathode of the voltage stabilizer is electrically connected to a cathode of the unidirectional conductive member;

[0019] A capacitor, wherein a first end of the capacitor is electrically connected to a cathode of the unidirectional conductive element and a cathode of the voltage stabilizer, and a second end of the capacitor is electrically connected to an anode of the voltage stabilizer and the first output end;

[0020] A negative voltage conductive element, wherein a source of the negative voltage conductive element is electrically connected to the first end of the first capacitor, a gate of the negative voltage conductive element is electrically connected to the first connection end, and a drain of the negative voltage conductive element is electrically connected to the second output end.

[0021] In some embodiments, a negative voltage auxiliary circuit is further included, wherein the first output terminal is electrically connected to the first control terminal via the negative voltage auxiliary circuit, and the second output terminal is electrically connected to the first conduction terminal via the negative voltage auxiliary circuit.

[0022] In some embodiments, the negative pressure auxiliary circuit includes:

[0023] A driving resistor, wherein the first output terminal is electrically connected to the first control terminal via the driving resistor;

[0024] A rapid negative pressure establishing module, one end of which is electrically connected to the first output end, and the other end of which is electrically connected to the second output end.

[0025] In some embodiments, the driving unit further comprises:

[0026] A second driving module includes a second control terminal and a second conduction terminal;

[0027] The driving transformer unit further includes a third connecting end and a fourth connecting end, and the third connecting end and the fourth connecting end are electrically connected to the second driving module respectively;

[0028] The switch unit further includes a second switch tube, a gate of the second switch tube is electrically connected to the second control end, and a source of the second switch tube is electrically connected to the second conduction end.

[0029] In some embodiments, the driving transformer unit further includes a fifth connection terminal, a sixth connection terminal, a seventh connection terminal and an eighth connection terminal; the switch unit further includes a third switch tube and a fourth switch tube;

[0030] The driving unit further comprises:

[0031] A third driving module, electrically connected to the fifth connection terminal and the sixth connection terminal respectively, the third driving module comprising a third control terminal and a third conduction terminal;

[0032] a fourth driving module, electrically connected to the seventh connection terminal and the eighth connection terminal respectively, the fourth driving module comprising a fourth control terminal and a fourth conduction terminal;

[0033] The gates of the three switch tubes are electrically connected to the third control terminal, and the sources are electrically connected to the third conduction terminal; the gate of the fourth switch module is electrically connected to the fourth control terminal, and the source is electrically connected to the fourth conduction terminal;

[0034] The driving unit is configured to drive the first driving module and the second driving module to work, and the third driving module and the fourth driving module not to work, or the first driving module and the second driving module not to work, and drive the third driving module and the fourth driving module to work.

[0035] In some embodiments, the first driving module includes a first control end and a first conduction end, and the third driving module includes a third control end and a third conduction end; the gate of the first switch tube is electrically connected to the first control end, the source of the first switch tube is grounded via the third switch tube, and the gate of the third switch tube is electrically connected to the third control end.

[0036] In some embodiments, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are silicon carbide MOS tubes.

[0037] The present invention further provides a welding machine, comprising a main transformer and the silicon carbide MOS transformer drive circuit of the aforementioned embodiment.

[0038] The beneficial effect of the technical solution of the present invention is that by adopting a transformer isolation solution, using a driving transformer unit to provide positive and negative voltages, and working in conjunction with the first driving module, efficient driving of the silicon carbide MOS tube is achieved. Through three stages of driving control, the positive voltage ensures that the switch unit is reliably turned on, the first negative voltage in the dead zone state gradually turns off the switch unit, and the superimposed second negative voltage further achieves deep shutdown, thereby effectively avoiding misconduction. Compared with traditional solutions, the present invention has the advantages of simple circuit, low cost, and high reliability. It is also suitable for high-power applications with multiple silicon carbide MOS tubes in parallel, which improves driving consistency and system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the electrical connection of modules of a silicon carbide MOS transformer driving circuit in one embodiment of the present invention;

[0040] Figure 2 is a circuit diagram of a silicon carbide MOS transformer driving circuit in one embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of module electrical connections of a silicon carbide MOS transformer driving circuit in another embodiment of the present invention;

[0042] Figure 4 A circuit diagram of a silicon carbide MOS transformer driving circuit in another embodiment of the present invention;

[0043] Figure 5 is a circuit diagram of a main transformer in another embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of module electrical connections of a silicon carbide MOS transformer driving circuit in another embodiment of the present invention;

[0045] Figure 7 A circuit diagram of a silicon carbide MOS transformer driving circuit in another embodiment of the present invention;

[0046] Figure 8 is a circuit diagram of a main transformer in another embodiment of the present invention;

[0047] Fig. 9 A circuit diagram of a silicon carbide MOS transformer driving circuit in yet another embodiment of the present invention;

[0048] Fig.10 FIG. 4 is a circuit diagram of a main transformer in yet another embodiment of the present invention.

[0049] Description of Figure Numbers:

[0050] 100. Drive unit;

[0051] 110, first driving module; A1, first control terminal; B1, first conduction terminal;

[0052] 112, negative voltage generating circuit; 113, first output terminal; 114, second output terminal; D1, unidirectional conductive element; Z1, voltage stabilizing element; C1, capacitor; C1A, first terminal; C1B, second terminal; Q5, negative voltage conductive element;

[0053] 115. Negative pressure auxiliary circuit; R1. driving resistor; 116. fast negative pressure establishment module;

[0054] 120, second driving module; A2, second control terminal; B2, second conduction terminal;

[0055] 130, a third driving module; A3, a third control terminal; B3, a third conduction terminal;

[0056] 140, fourth driving module; A4, fourth control terminal; B4, fourth conduction terminal;

[0057] 200, driving transformer unit; 201, first connection end; 202, second connection end; 203, third connection end; 204, fourth connection end; 205, fifth connection end; 206, sixth connection end; 207, seventh connection end; 208, eighth connection end;

[0058] 300, switch unit;

[0059] Q1, first switch tube; Q2, second switch tube; Q3, third switch tube; Q4, fourth switch tube;

[0060] T1, main transformer.

[0061] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0062] The scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0064] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0065] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0066] Reference Figure 1 and Figure 2 , an embodiment of the present invention provides a transformer driving circuit of a silicon carbide MOS, and the transformer driving circuit of the silicon carbide MOS includes:

[0067] The driving unit 100 includes a first driving module 110, and the first driving module 110 includes a first control terminal A1 and a first conduction terminal B1;

[0068] A driving transformer unit 200, the driving transformer unit 200 comprises a first connection end 201 and a second connection end 202, the first connection end 201 and the second connection end 202 are electrically connected to the first driving module 110 respectively;

[0069] The switch unit 300 is electrically connected to the first control terminal A1 and the first conduction terminal B1 respectively;

[0070] The driving transformer unit 200 generates a forward voltage and transmits it to the first driving module 110 through the first connecting terminal 201. The first driving module 110 controls the switch unit 300 to conduct based on the forward voltage.

[0071] The driving transformer unit 200 is in a dead zone state, and the first driving module 110 generates a first negative voltage to drive the switch unit 300 to turn off;

[0072] The driving transformer unit 200 generates a second negative voltage and transmits it to the first driving module 110 through the second connection terminal 202 to be superimposed with the first negative voltage to control the switch unit 300 to be in a deep cut-off state.

[0073] In this embodiment, the driving unit 100 is mainly used to drive a MOS tube, mainly a silicon carbide MOS tube. As the name implies, a silicon carbide MOS tube (SiC MOSFET) is a metal oxide semiconductor field effect transistor based on silicon carbide material. The high electron mobility of silicon carbide material enables it to achieve a faster switching speed than a silicon MOS tube, and SiC MOSFET can operate at a higher temperature, and its junction temperature can usually reach 175°C or even higher, which is suitable for high-power applications in harsh environments.

[0074] The driving unit 100 includes one or more driving modules, such as a first driving module 110, a second driving module 120, etc. The first driving module 110 has a first control terminal A1 and a first conduction terminal B1, which are used to transmit a driving signal to the MOS tube. The driving unit 100 can expand multiple driving modules according to demand to realize the control of multiple silicon carbide MOS tubes.

[0075] The driving transformer unit 200 is mainly used to apply positive voltage and negative voltage to the first driving module 110. The driving transformer unit 200 can adopt a transformer structure, and use the secondary winding of the transformer to output voltage signals of different polarities to provide the voltage required for the driving module to work.

[0076] The switch unit 300 may be one or more silicon carbide MOS tubes for actual power switch control operation. In this embodiment, the switch unit 300 may be an NPN type silicon carbide MOS tube. The structure of the switch unit 300 may be flexibly configured according to power requirements, and may be a single MOS tube or multiple MOS tubes in parallel.

[0077] In one working cycle, the SiC MOS transformer drive circuit operates in the following three time periods:

[0078] In the first time period (forward drive), the driving transformer unit 200 generates a forward voltage and transmits it to the first driving module 110 through the first connection terminal 201. After receiving the forward voltage, the first driving module 110 quickly applies the voltage to the switching unit 300 to increase its gate voltage to the on state, and the silicon carbide MOS tube starts to conduct.

[0079] In this stage, the main power path is fully opened, and the circuit enters the normal power transmission state, providing a stable current to the load.

[0080] In the second time period (initial shutdown), the driving transformer unit 200 enters the dead zone state, that is, the transformer secondary winding no longer provides an output voltage. In this time period, the first driving module 110 releases the previously stored electric energy into a negative voltage through its internal energy storage unit (such as capacitor C1) to control the switch unit 300 to gradually shut down.

[0081] At this time, the gate voltage of the switch unit 300 gradually decreases, and the silicon carbide MOS tube gradually transitions from a fully on state to an off state. This process is stable and controllable, avoiding overvoltage problems in the circuit caused by rapid shutdown.

[0082] In the third time period (deep shutdown), the driving transformer unit 200 generates a second negative voltage in this stage and transmits it to the first driving module 110 through the second connection terminal 202. The first driving module 110 superimposes the second negative voltage on the first negative voltage and applies it to the gate of the switch unit 300. The superposition effect of the two negative voltages ensures that the switch unit 300 completely enters the deep cutoff state, eliminates leakage current and mis-conduction phenomena, and improves the overall efficiency and reliability of the circuit.

[0083] In this way, through the close coordination of the above three time periods, the opening and closing of the silicon carbide MOS tube are precisely controlled. The superimposed negative drive in the deep shutdown stage effectively enhances the anti-interference ability of the circuit and improves the safety of the overall system.

[0084] The present invention realizes efficient driving of silicon carbide MOS tubes by adopting a transformer isolation solution, using the driving transformer unit 200 to provide positive and negative voltages, and combining the coordinated work of the energy storage unit inside the first driving module 110. Through three stages of driving control, the positive voltage ensures that the switch unit 300 is reliably turned on, and the negative voltage in the dead zone state gradually turns off the switch unit 300. The superimposed negative voltage further realizes deep shutdown, thereby effectively avoiding mis-conduction. Compared with traditional solutions, the present invention has the advantages of simple circuit, low cost and high reliability. It is also suitable for high-power applications with multiple silicon carbide MOS tubes in parallel, which significantly improves the driving consistency and system performance.

[0085] Continue reading Figure 2 In this embodiment, the first driving module 110 includes:

[0086] A negative voltage generating circuit 112, the negative voltage generating circuit 112 is electrically connected to the first connection terminal 201 and the second connection terminal 202 respectively, and the negative voltage generating circuit 112 includes a first output terminal 113 and a second output terminal 114; the first output terminal 113 is electrically connected to the first control terminal A1, and the second output terminal 114 is electrically connected to the first conduction terminal B1;

[0087] The switch unit 300 includes a first switch tube Q1 , a gate of the first switch tube Q1 is electrically connected to a first control terminal A1 , a source of the first switch tube Q1 is electrically connected to a first conduction terminal B1 , and a drain of the first switch tube is electrically connected to a power source.

[0088] In the first time period, when the driving transformer unit 200 generates a forward voltage (current flows from the second connection terminal 202 to the first connection terminal 201), the negative voltage generating circuit 112 obtains the forward voltage through the first connection terminal 201. After obtaining the forward voltage, the negative voltage generating circuit 112 transmits the forward voltage to the gate of the first switch tube Q1 of the switch unit 300 to turn it on. At the same time, the negative voltage generating circuit 112 uses part of the forward voltage for internal energy storage to prepare for the negative drive in the subsequent stage.

[0089] In this stage, the first switch tube Q1 of the switch unit 300 enters the on state, that is, the silicon carbide MOS tube is in the working state, and the main power path is opened.

[0090] In the second time period, when the driving transformer unit 200 enters the dead zone state (the first connection terminal 201 and the second connection terminal 202 are both at zero potential), the negative voltage generating circuit 112 generates a first negative voltage using the electric energy stored in the first time period. The first negative voltage acts on the gate of the first switch tube Q1 of the switch unit 300, so that its gate voltage is reduced and gradually enters the off state.

[0091] At this time, the silicon carbide MOS tube gradually transitions from the on state to the off state, ensuring a smooth shutdown process and avoiding overvoltage problems.

[0092] In the third time period, when the driving transformer unit 200 generates a second negative voltage (current flows from the first connection terminal 201 to the second connection terminal 202), the second negative voltage is transmitted to the negative voltage generating circuit 112 through the second connection terminal 202 and is superimposed on the first negative voltage. The superimposed negative voltage is applied to the gate of the first switch tube Q1, so that its gate voltage is further reduced to a deep cut-off state.

[0093] At this stage, the silicon carbide MOS tube completely enters a deep shutdown state, eliminating leakage current and misconduction, ensuring the stability and reliability of the system.

[0094] This embodiment realizes efficient driving of the silicon carbide MOS tube through the coordinated work of the negative voltage generating circuit 112 and the driving transformer unit 200. The negative voltage generating circuit 112 can not only use the positive voltage to drive the switch unit 300 to turn on, but also generate a negative voltage in the dead zone stage to gradually turn off, and achieve deep cutoff in the negative superposition stage. Through the three-stage driving process, this embodiment has the technical advantages of simple circuit, low cost and high reliability when driving the silicon carbide MOS tube.

[0095] Continue reading Figure 2 In this embodiment, the negative voltage generating circuit 112 includes:

[0096] A one-way conductive member D1, wherein an anode of the one-way conductive member D1 is electrically connected to a first connection end 201;

[0097] A voltage stabilizer Z1, a cathode of the voltage stabilizer is electrically connected to a cathode of the unidirectional conductive element D1;

[0098] A capacitor C1, wherein a first end C1A of the capacitor C1 is electrically connected to a cathode of the unidirectional conductive element D1 and a cathode of the voltage stabilizer, and a second end C1B of the capacitor C1 is electrically connected to an anode of the voltage stabilizer and a first output end 113;

[0099] The negative voltage conduction element Q5 has a source electrically connected to the first end C1A of the first capacitor C1 , a gate electrically connected to the first connection end 201 , and a drain electrically connected to the second output end 114 .

[0100] In this embodiment, the unidirectional conductive element D1 may be a fast diode, whose anode is electrically connected to the first connection terminal 201. During forward driving, the fast diode is turned on to ensure the establishment of a stable forward voltage.

[0101] The voltage stabilizer Z1 may be a voltage stabilizer diode, whose cathode is electrically connected to the cathode of the unidirectional conductor D1 and whose anode is electrically connected to the second end C1B of the capacitor C1. The voltage stabilizer diode may have a voltage value between 3V and 8V, which is used to limit the amplitude of the negative voltage and stabilize the circuit.

[0102] Capacitor C1 is used for negative voltage filtering and energy storage. A high-frequency capacitor C1 can be selected, and its capacity range is between 0.1 μF and 5 μF. The first end C1A of capacitor C1 is electrically connected to the cathode of the unidirectional conductive element D1 and the cathode of the voltage regulator diode, and the second end C1B is electrically connected to the anode of the voltage regulator diode and the first output end 113.

[0103] The negative voltage conduction element Q5 may be a P-channel MOS transistor, whose source is electrically connected to the first terminal C1A of the capacitor C1, the gate is electrically connected to the first connection terminal 201, and the drain is electrically connected to the second output terminal 114. The P-channel MOS transistor is used as a negative voltage path switch element to control the transmission of negative voltage.

[0104] In the first time period (forward drive), the driving transformer unit 200 outputs a forward voltage to the first driving module 110 through the first connection terminal 201. At this time, the unidirectional conductive element D1 is turned on, and the forward voltage (about 1.1V) is transmitted to the first end C1A of the capacitor C1 through the fast diode. The first end C1A of the capacitor C1 is the positive electrode, and the second end C1B is the negative electrode, and electrical energy begins to be stored. At the same time, the forward voltage is applied to the gate of the negative voltage conductive element Q5 (P-channel MOS tube), making it in the cut-off state, and the forward voltage is transmitted to the gate of the first switch tube Q1 through the first driving module 110, so that the first switch tube Q1 is turned on, and the main power path is opened.

[0105] In the second time period, the driving transformer unit 200 enters the dead zone state (the first connection terminal 201 and the second connection terminal 202 are both at zero potential). At this time, the negative voltage conductive element Q5 has no voltage on the gate based on the characteristics of the P-channel MOS and begins to gradually conduct. The fast diode is turned off due to the lack of forward voltage input. At this time, the first end C1A of the capacitor C1 becomes the negative electrode, and the second end C1B becomes the positive electrode. The stored electric energy is output from the positive electrode, and a stable negative voltage output is provided through the voltage-stabilizing diode. The first negative voltage generated by the capacitor C1 is transmitted to the second output terminal 114 through the negative voltage conductive element Q5, and at the same time acts on the gate of the first switch tube Q1, so that its gate voltage is gradually reduced, and the switch tube enters the initial shutdown state.

[0106] In the third time period (entering the deep shutdown state), the driving transformer unit 200 outputs a second negative voltage (the current direction flows from the first connection terminal 201 to the second connection terminal 202) through the first connection terminal 201 and the second connection terminal 202. At this time, the second negative voltage is transmitted to the first driving module 110 through the second connection terminal 202, superimposed with the first negative voltage released by the capacitor C1, and flows to the first conduction terminal B1. The superimposed negative voltage further reduces the gate voltage of the first switch tube Q1, so that it completely enters the deep cutoff state, and eliminates leakage current and mis-conduction phenomena.

[0107] In this way, through the synergistic effect of the two-level negative voltage, the switch tube can be reliably shut down, thereby improving the stability and anti-interference ability of the circuit.

[0108] This embodiment realizes efficient use of positive voltage and accurate generation of negative voltage through the multi-stage drive design of the negative voltage generation circuit 112. In multiple time periods, the orderly cooperation of positive drive, energy storage, negative drive and deep shutdown ensures the stable operation of the switch tube, while significantly improving the reliability and applicability of the circuit.

[0109] Continue reading Figure 2In this embodiment, the silicon carbide MOS transformer driving circuit also includes a negative voltage auxiliary circuit 115, the first output terminal 113 is electrically connected to the first control terminal A1 through the negative voltage auxiliary circuit 115, and the second output terminal 114 is electrically connected to the first conduction terminal B1 through the negative voltage auxiliary circuit 115.

[0110] In this embodiment, the silicon carbide MOS transformer driving circuit also includes a negative voltage auxiliary circuit 115 for enhancing the effect of negative voltage generation and ensuring its stable transmission. The negative voltage auxiliary circuit 115 is connected to the first control terminal A1 through the first output terminal 113, and the second output terminal 114 is connected to the first conduction terminal B1. In the positive driving stage, the charging efficiency of the capacitor C1 is optimized, and in the initial shutdown stage, the capacitor C1 is assisted to discharge and stabilize the first negative voltage, and in the deep shutdown stage, the negative voltage superposition effect is maximized, thereby improving the reliability of negative voltage transmission and the overall consistency of the system.

[0111] Continue reading Figure 2 In this embodiment, the negative pressure auxiliary circuit 115 includes:

[0112] The driving resistor R1, the first output terminal 113 is electrically connected to the first control terminal A1 via the driving resistor R1;

[0113] The rapid negative pressure establishing module 116 has one end electrically connected to the first output end 113 and the other end electrically connected to the second output end 114 .

[0114] In this embodiment, the driving resistor R1 is located between the first output terminal 113 and the first control terminal A1, and is used to drive the silicon carbide MOS gate. The driving resistor R1 has a value ranging from 4.7Ω to 51Ω, which can be adjusted according to specific circuit requirements.

[0115] The fast negative voltage establishment module 116 includes a fast diode D2 and a resistor R2, one end of the fast diode D2 is connected to the first output terminal 113, and the other end is connected to the second output terminal 114 through the resistor R2. Among them, the diode D2 is a fast diode, which is only turned on when the pulse signal is positive, and is used to avoid the problem that the negative voltage cannot be established when the pulse width is narrow. The value range of the resistor R2 is 1kΩ to 51kΩ, which plays the role of current limiting and stabilizing the negative voltage.

[0116] The charge discharge resistor R3 is used to discharge the static electricity between the silicon carbide MOS gate and the source to avoid damage to the device due to static electricity accumulation. The value range can be 3kΩ to 100kΩ.

[0117] The waveform adjustment capacitor C2 is used to adjust the rising and falling edges of the silicon carbide MOS gate-source drive waveform. C2 can effectively eliminate the high-order harmonic components in the drive signal and improve electromagnetic compatibility (EMI).

[0118] This embodiment constructs a perfect negative voltage auxiliary circuit 115 through the combination of the driving resistor R1, the fast negative voltage establishment module 116, the charge discharge resistor and the driving waveform adjustment capacitor C1. This design can not only quickly establish a negative voltage signal, but also optimize the driving waveform, improve electromagnetic compatibility, and avoid static electricity damage to silicon carbide MOS devices, thereby improving the reliability and stability of the system.

[0119] See also Figure 3 , Figure 4 and Figure 5 In this embodiment, the driving unit 100 further includes:

[0120] The second driving module 120 includes a second control terminal A2 and a second conduction terminal B2;

[0121] The driving transformer unit 200 further includes a third connecting terminal 203 and a fourth connecting terminal 204, and the third connecting terminal 203 and the fourth connecting terminal 204 are electrically connected to the second driving module 120 respectively;

[0122] The switch unit 300 further includes a second switch tube Q2, a gate of the second switch tube Q2 is electrically connected to the second control terminal A2, and a source of the second switch tube Q2 is electrically connected to the second conduction terminal B2.

[0123] In this embodiment, the silicon carbide MOS transformer driving circuit includes two driving modules, namely a first driving module 110 and a second driving module 120, which are respectively used to drive two switch tubes to realize the control of the main transformer T1.

[0124] The first driving module 110 includes a first control terminal A1 and a first conduction terminal B1, and is used to control the first switch tube Q1.

[0125] The second driving module 120 includes a second control terminal A2 and a second conduction terminal B2, and is used to control the second switch tube Q2.

[0126] The driving transformer unit 200 is a driving transformer, wherein two secondary windings of the driving transformer are in the same direction, that is, the winding directions of the coils are consistent.

[0127] The driving transformer unit 200 includes a third connection terminal 203 and a fourth connection terminal 204, which are electrically connected to the second driving module 120 respectively, so as to ensure that the two driving modules can work simultaneously.

[0128] The switch unit 300 includes two switch tubes, namely a first switch tube Q1 and a second switch tube Q2.

[0129] The gate of the first switch tube Q1 is electrically connected to the first control terminal A1, and the source is electrically connected to the first conduction terminal B1.

[0130] The gate of the second switch tube Q2 is electrically connected to the second control terminal A2, and the source is electrically connected to the second conduction terminal B2.

[0131] In this embodiment, the driving transformer provides driving signals to the first driving module 110 and the second driving module 120 through two secondary windings. Since the winding directions of the secondary windings are consistent, the signals received by the two driving modules have the same phase, thereby achieving synchronous control of the two switching tubes.

[0132] In the forward driving stage, when the driving transformer outputs a forward driving signal, the first driving module 110 controls the first switch tube Q1 to turn on, and the second driving module 120 controls the second switch tube Q2 to turn on. At this time, the primary side of the main transformer T1 forms a path, which is achieved in this stage.

[0133] When the driving transformer enters the dead zone state or outputs a negative signal, the first driving module 110 and the second driving module 120 respectively control the first switch tube Q1 and the second switch tube Q2 to turn off. At this time, the primary side of the main transformer T1 is disconnected and energy transfer stops.

[0134] By using two driving modules to control two switch tubes respectively and using the same-direction secondary winding output signal of the driving transformer, this embodiment realizes the synchronous switching of the two switch tubes, effectively improving the control accuracy of the main transformer T1. At the same time, the two driving modules work synchronously to ensure the stable operation of the main transformer T1.

[0135] See also Figure 6 , Figure 7 and Figure 8 In this embodiment, the driving transformer unit 200 further includes a fifth connection terminal 205, a sixth connection terminal 206, a seventh connection terminal 207 and an eighth connection terminal 208; the switch unit 300 further includes a third switch tube Q3 and a fourth switch tube Q4;

[0136] The drive unit 100 further includes:

[0137] The third driving module 130 is electrically connected to the fifth connection terminal 205 and the sixth connection terminal 206 respectively, and the third driving module 130 includes a third control terminal A3 and a third conduction terminal B3;

[0138] The fourth driving module 140 is electrically connected to the seventh connection terminal 207 and the eighth connection terminal 208 respectively, and the fourth driving module 140 includes a fourth control terminal A4 and a fourth conduction terminal B4;

[0139] The gate of the third switch tube is electrically connected to the third control terminal A3, and the source is electrically connected to the third conduction terminal B3; the gate of the fourth switch module is electrically connected to the fourth control terminal A4, and the source is electrically connected to the fourth conduction terminal B4;

[0140] The driving unit 100 is configured to drive the first driving module 110 and the second driving module 120 to work, and the third driving module 130 and the fourth driving module 140 not to work, or the first driving module 110 and the second driving module 120 not to work, and drive the third driving module 130 and the fourth driving module 140 to work.

[0141] In this embodiment, the silicon carbide MOS transformer driving circuit further includes four driving modules, which are paired and work synchronously to achieve bidirectional control of the main transformer T1.

[0142] The driving transformation unit 200 includes a fifth connection terminal 205 , a sixth connection terminal 206 , a seventh connection terminal 207 and an eighth connection terminal 208 , and is used to provide driving signals for the third driving module 130 and the fourth driving module 140 .

[0143] The switch unit 300 adds a third switch tube Q3 and a fourth switch tube Q4. The gate of the third switch tube Q3 is electrically connected to the third control terminal A3, and the source is electrically connected to the third conduction terminal B3. The gate of the fourth switch tube Q4 is electrically connected to the fourth control terminal A4, and the source is electrically connected to the fourth conduction terminal B4.

[0144] Specifically, the four driving modules in the driving unit 100 are divided into two groups, and work synchronously in pairs to achieve control of the main transformer T1.

[0145] In the first working mode, the first driving module 110 and the second driving module 120 work synchronously, driving the first switch tube Q1 and the second switch tube Q2 to turn on. At this time, the current of the main transformer T1 flows in a fixed direction, completing an energy transfer. The third driving module 130 and the fourth driving module 140 do not work, and the third switch tube Q3 and the fourth switch tube Q4 are in the off state.

[0146] In the second working mode, the third driving module 130 and the fourth driving module 140 work synchronously, driving the third switch tube Q3 and the fourth switch tube Q4 to turn on, and the current direction of the main transformer T1 flows in the reverse direction to achieve the energy transfer of the other half cycle of the alternating current. At this time, the first driving module 110 and the second driving module 120 do not work, and the first switch tube Q1 and the second switch tube Q2 are in the off state.

[0147] In this embodiment, the control of the main transformer T1 realizes the change of the current direction by switching the driving module, thereby generating an AC signal. Among them, the coil winding direction of the secondary winding driving the first driving module 110 and the second driving module 120 is the same, and the coil winding direction of the secondary winding driving the third driving module 130 and the fourth driving module 140 is the same.

[0148] Specifically, when the first driving module 110 and the second driving module 120 are working, the current of the main transformer T1 flows from one end of the primary winding to the other end, forming a positive current. When the third driving module 130 and the fourth driving module 140 are working, the current direction of the main transformer T1 flows in the opposite direction, forming a negative current. Through this forward and reverse switching, the main transformer T1 achieves a stable AC output and ensures efficient power transmission.

[0149] In this way, precise control of the forward and reverse currents of the main transformer T1 is achieved through the pairing of the first driving module 110 and the second driving module 120 , and the third driving module 130 and the fourth driving module 140 .

[0150] In summary, this embodiment achieves efficient control of the main transformer T1 through the coordinated design of the drive unit 100, the drive transformer unit 200 and the switch unit 300, thereby ensuring stable operation of the system in various working modes.

[0151] See also Fig. 9 and Fig.10 In this embodiment, the first driving module 110 includes a first control terminal A1 and a first conduction terminal B1, and the third driving module 130 includes a third control terminal A3 and a third conduction terminal B3; the gate of the first switch tube Q1 is electrically connected to the first control terminal A1, the source of the first switch tube Q1 is grounded via the third switch tube Q3, and the gate of the third switch tube Q3 is electrically connected to the third control terminal A3.

[0152] In this embodiment, the secondary winding of the driving transformer unit 200 can be designed as two windings in different directions, respectively driving the first driving module 110 and the third driving module 130. Specifically, the coil winding direction of the secondary winding driving the first driving module 110 is one direction, while the coil winding direction of the secondary winding driving the third driving module 130 is opposite.

[0153] The first driving module 110 includes a first control terminal A1 and a first conduction terminal B1. The first driving module 110 receives a signal by driving the secondary winding of the transformer unit 200, and the winding direction is forward.

[0154] The third driving module 130 includes a third control terminal A3 and a third conduction terminal B3. The third driving module 130 receives a signal by driving another secondary winding of the transformer unit 200, and the winding direction thereof is reverse.

[0155] The gate of the first switch tube Q1 is electrically connected to the first control terminal A1 of the first driving module 110 , and the source is grounded through the third switch tube Q3 . The gate of the third switch tube Q3 is electrically connected to the third control terminal A3 of the third driving module 130 .

[0156] In the forward driving stage, the driving transformer unit 200 provides a forward driving signal to the first driving module 110, and the first driving module 110 controls the first switch tube Q1 to turn on. At the same time, the driving transformer unit 200 provides a reverse signal to the third driving module 130, and the third driving module 130 controls the third switch tube Q3 to turn off. In this stage, the main circuit forms a path to achieve forward energy transfer.

[0157] In the reverse driving stage, the driving transformer unit 200 provides a forward driving signal to the third driving module 130, and the third driving module 130 controls the third switch tube Q3 to be turned on. At the same time, the driving transformer unit 200 provides a reverse signal to the first driving module 110, and the first driving module 110 controls the first switch tube Q1 to be turned off. In this stage, the main circuit realizes a reverse path and completes reverse energy transfer. In this way, by designing the secondary winding of the driving transformer unit 200 as two windings in different directions and cooperating with the driving module, this embodiment realizes bidirectional control of the main transformer T1.

[0158] In some embodiments, the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 , and the fourth switch tube Q4 are silicon carbide MOS tubes.

[0159] The present invention further proposes a welding machine comprising a main transformer T1 and the aforementioned silicon carbide MOS transformer drive circuit. The specific structure of the welding machine refers to the above embodiment. Since the welding machine adopts all the technical solutions of all the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0160] In this embodiment, since the silicon carbide MOS transformer drive circuit can realize high-frequency and efficient drive control, the main transformer T1 of the welding machine can work stably at high frequency, thereby improving the overall efficiency of the welding machine. At the same time, the forward and reverse drive mechanism in the silicon carbide MOS transformer drive circuit ensures the bidirectional current control of the main transformer T1, meets the needs of the welding machine in a complex welding environment, and is suitable for a variety of working modes.

[0161] In addition, through efficient energy transmission and low-loss drive circuit design, the energy consumption of the welding machine is significantly reduced during use, and it has higher energy utilization rate.

[0162] The welding machine of this embodiment adopts a silicon carbide MOS transformer drive circuit, so that the welding machine has the advantages of high efficiency, energy saving, high reliability, strong applicability, etc.

[0163] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A silicon carbide MOS transformer driving circuit, characterized in that: include: A driving unit, the driving unit comprising a first driving module, the first driving module comprising a first control end and a first conduction end; A driving transformer unit, the driving transformer unit comprising a first connecting end and a second connecting end, the first connecting end and the second connecting end being electrically connected to the first driving module respectively; a switch unit, the switch unit being electrically connected to the first control end and the first conduction end respectively; The driving transformer unit generates a forward voltage and transmits it to the first driving module through the first connecting end, and the first driving module controls the switch unit to conduct based on the forward voltage; The driving transformer unit is in a dead zone state, and the first driving module generates a first negative voltage to drive the switch unit to turn off; The driving transformer unit generates a second negative voltage and transmits it to the first driving module through the second connecting terminal, so as to be superimposed with the first negative voltage to control the switch unit to be in a deep cut-off state.

2. The silicon carbide MOS transformer driving circuit according to claim 1, characterized in that: The first driving module comprises: A negative voltage generating circuit, wherein the negative voltage generating circuit is electrically connected to the first connection terminal and the second connection terminal respectively, and the negative voltage generating circuit comprises a first output terminal and a second output terminal; the first output terminal is electrically connected to the first control terminal, and the second output terminal is electrically connected to the first conduction terminal; The switch unit includes a first switch tube, a gate of the first switch tube is electrically connected to the first control end, a source of the first switch tube is electrically connected to the first conduction end, and a drain of the first switch tube is electrically connected to a power supply.

3. The silicon carbide MOS transformer driving circuit according to claim 2, characterized in that: The negative voltage generating circuit comprises: A one-way conductive member, wherein an anode of the one-way conductive member is electrically connected to the first connection end; A voltage stabilizer, wherein a cathode of the voltage stabilizer is electrically connected to a cathode of the unidirectional conductive member; A capacitor, wherein a first end of the capacitor is electrically connected to a cathode of the unidirectional conductive element and a cathode of the voltage stabilizer, and a second end of the capacitor is electrically connected to an anode of the voltage stabilizer and the first output end; A negative voltage conductive element, wherein a source of the negative voltage conductive element is electrically connected to the first end of the first capacitor, a gate of the negative voltage conductive element is electrically connected to the first connection end, and a drain of the negative voltage conductive element is electrically connected to the second output end.

4. The silicon carbide MOS transformer driving circuit according to claim 1 or 3, characterized in that: It also includes a negative voltage auxiliary circuit, the first output end is electrically connected to the first control end via the negative voltage auxiliary circuit, and the second output end is electrically connected to the first conduction end via the negative voltage auxiliary circuit.

5. The silicon carbide MOS transformer driving circuit according to claim 4, characterized in that: The negative pressure auxiliary circuit comprises: A driving resistor, wherein the first output terminal is electrically connected to the first control terminal via the driving resistor; A rapid negative pressure establishing module, one end of which is electrically connected to the first output end, and the other end of which is electrically connected to the second output end.

6. The silicon carbide MOS transformer driving circuit according to any one of claim 2, characterized in that: The driving unit further comprises: A second driving module includes a second control terminal and a second conduction terminal; The driving transformer unit further includes a third connecting end and a fourth connecting end, and the third connecting end and the fourth connecting end are electrically connected to the second driving module respectively; The switch unit further includes a second switch tube, a gate of the second switch tube is electrically connected to the second control end, and a source of the second switch tube is electrically connected to the second conduction end.

7. The silicon carbide MOS transformer driving circuit according to claim 6, characterized in that: The driving transformer unit further includes a fifth connection terminal, a sixth connection terminal, a seventh connection terminal and an eighth connection terminal; the switch unit further includes a third switch tube and a fourth switch tube; The driving unit further comprises: A third driving module, electrically connected to the fifth connection terminal and the sixth connection terminal respectively, the third driving module comprising a third control terminal and a third conduction terminal; a fourth driving module, electrically connected to the seventh connection terminal and the eighth connection terminal respectively, the fourth driving module comprising a fourth control terminal and a fourth conduction terminal; The gate of the third switch tube is electrically connected to the third control terminal, and the source is electrically connected to the third conduction terminal; the gate of the fourth switch module is electrically connected to the fourth control terminal, and the source is electrically connected to the fourth conduction terminal; The driving unit is configured to drive the first driving module and the second driving module to work, and the third driving module and the fourth driving module not to work, or the first driving module and the second driving module not to work, and drive the third driving module and the fourth driving module to work.

8. The silicon carbide MOS transformer driving circuit according to claim 7, characterized in that: The first driving module includes a first control end and a first conduction end, and the third driving module includes a third control end and a third conduction end; the gate of the first switch tube is electrically connected to the first control end, the source of the first switch tube is grounded via the third switch tube, and the gate of the third switch tube is electrically connected to the third control end.

9. The silicon carbide MOS transformer driving circuit according to claim 7, characterized in that: The first switch tube, the second switch tube, the third switch tube and the fourth switch tube are silicon carbide MOS tubes.

10. A welding machine, characterized in that: It comprises a main transformer and the silicon carbide MOS transformer drive circuit according to any one of claims 1 to 9.

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