CN206415752U - High power density high efficiency WBG arc welding inverters - Google Patents

Abstract

The utility model provides a high power density and high efficiency WBG arc welding inverter, which is characterized in that: it includes a main circuit and a closed-loop control circuit; the main circuit includes an electromagnetic compatibility module, a power frequency rectification and filtering module, a WBG high frequency Converter module, high-frequency power transformer and high-frequency rectification and filtering module; Among them, the electromagnetic compatibility module is externally connected to three-phase/single-phase AC input power supply, and the high-frequency rectification and filtering module is externally connected to arc load; the closed-loop control circuit includes electrical signal real-time detection module, human Machine interaction module, fault diagnosis module, controller and WBG high frequency drive and protection module. The arc welding inverter has higher power density and efficiency, excellent dynamic response performance and process performance, and good reliability and stability.

Description

High power density and high efficiency WBG arc welding inverter

technical field

The utility model relates to the technical field of arc welding inverters, in particular to a WBG arc welding inverter with high power density and high efficiency.

Background technique

The welding power supply provides energy for the welding arc, and its performance directly affects the welding process effect. According to statistics, arc welding inverter power supply has become the mainstream product in the domestic welding machine market, and is developing in the direction of large capacity, light weight, high efficiency, modularization, and intelligence. At present, the power devices (including MOSFET, IGBT, SBD, FRD, etc.) widely used in arc welding inverter power supply are all silicon semiconductor devices. The switching performance of these silicon power devices has been close to the theoretical limit determined by their material characteristics with the improvement of their structural design and manufacturing process. The potential for continuing to improve and improve the performance of arc welding inverter power supplies by relying on silicon power devices is very limited. There is an urgent need Rely on new materials to meet the higher requirements of the new generation of welding power supplies for device performance.

Wide Band Gap (WBG) semiconductors mainly refer to semiconductor materials with a band gap (the energy difference between the lowest point of the conduction band and the highest point of the valence band) greater than 2.2eV. Wide bandgap semiconductor is a revolutionary power electronic material. Its band gap is much larger than that of silicon semiconductor, which can significantly reduce the gap that electrons cross, making it easier to control current and reduce energy consumption. Wide bandgap semiconductor materials represented by GaN and SiC have the characteristics of high breakdown electric field strength, high cut-off frequency, high thermal conductivity, high junction temperature, good thermal stability, and strong radiation resistance. These characteristics of semiconductor materials enable WBG power devices to be applied in high temperature and strong radiation environments that traditional devices are not capable of.

The arc welding inverter power supply needs to work for a long time in the harsh process environment of high voltage, high current, high power and even frequent high no-load-short circuit arcing. WBG power devices must withstand high voltage, high current, high temperature, high frequency, and Due to the combined effects of high di/dt, du/dt and other multi-parameter and complex stresses, their operational reliability has become a key issue for WBG power devices to be successfully applied to arc welding inverter power supplies. Compared with Si power devices, the forward conduction curve and reverse recovery curve of WBG power devices are significantly different. Such as reverse blocking ability, reverse recovery characteristics and thermal stability) and switching process (such as voltage overshoot and current spikes caused by internal parasitic effects and correlation with temperature changes) have their particularity, in the process of operation The loss distribution (conduction loss, resistance loss and reverse recovery loss) under the action of high-frequency electromagnetic pulse energy is also very different from that of Si-based power devices. Therefore, WBG power devices cannot directly replace Si-based power devices and be applied to arc welding inverter power supplies. It is necessary to further establish the electrical model of WBG power devices and conduct simulation research on dynamic electrothermal coupling, so as to optimize the topology and drive circuits. Design lays the groundwork.

Utility model content

The purpose of the utility model is to overcome the shortcomings and deficiencies in the prior art, and provide a WBG arc welding inverter with high power density, high efficiency, excellent dynamic response performance and process performance, and good reliability and stability .

In order to achieve the above object, the utility model is realized through the following technical scheme: a high power density and high efficiency WBG arc welding inverter, characterized in that: it includes a main circuit and a closed-loop control circuit; the main circuit includes sequentially connected Electromagnetic compatibility module, power frequency rectification and filtering module, WBG high-frequency commutation module, high-frequency power transformer and high-frequency rectification and filtering module; among them, the electromagnetic compatibility module is connected with three-phase/single-phase AC input power externally, and the high-frequency rectification and filtering module is connected with arc load;

The closed-loop control circuit includes an electrical signal real-time detection module, a human-computer interaction module, a fault diagnosis module, a controller, and a WBG high-frequency drive and protection module;

The WBG high-frequency drive and protection module is respectively connected with the WBG high-frequency commutation module, fault diagnosis module, electrical signal real-time detection module and controller; the fault diagnosis module is also connected with three-phase/single-phase AC input power supply, WBG The high-frequency commutation module, the high-frequency power transformer and the controller are connected; the electrical signal real-time detection module is also connected with the high-frequency power transformer, the arc load, the controller and the human-computer interaction module respectively; the human-computer interaction module is also connected with the Controller connection.

Preferably, the WBG high frequency converter module includes WBG power device Q1, WBG power device Q2, WBG power device Q3, WBG power device Q4, freewheeling diode D7, freewheeling diode D8, freewheeling diode D9, freewheeling diode D10, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16 and inductor Lr; the high frequency power transformer includes inductor Lm and transformer T1; the high frequency rectifier filter module includes WBG power rectifier DR1, WBG power rectifier Tube DR2, inductor Lo and capacitor C17;

The power frequency rectification filter module is connected in parallel with the series circuit composed of WBG power device Q1 and WBG power device Q3, and is connected in parallel with the series circuit composed of WBG power device Q2 and WBG power device Q4; the freewheeling diode D7 and capacitor C12 are respectively connected in parallel WBG power device Q1; freewheeling diode D8 and capacitor C13 are respectively connected in parallel to WBG power device Q2; freewheeling diode D9 and capacitor C14 are respectively connected in parallel on WBG power device Q3; freewheeling diode D10 and capacitor C15 are respectively connected in parallel to WBG power On device Q4; the connection point of WBG power device Q1 and WBG power device Q3 and the connection point of WBG power device Q2 and WBG power device Q are connected through the primary of transformer T1, capacitor C16 and inductor Lr; the inductor Lm is connected in parallel to the primary of transformer T1 above; the first output terminal of the secondary of the transformer T1 is connected to the second output terminal of the secondary of the transformer T1 through the WBG power rectifier DR1, the inductor Lo and the capacitor C17; The rectifier DR2 is connected to the third output terminal of the secondary of the transformer T1; the arc load is connected in parallel with the capacitor C17.

Preferably, the WBG high-frequency drive and protection module includes a system-level fault detection processing circuit, a power-level fault detection processing circuit, a device-level fault detection processing circuit, a drive mode selection circuit, a fault type output circuit, and a bidirectional magnetic pulse isolation transmission circuit , signal logic processing circuit, signal conversion interface circuit, signal reconstruction circuit, power operational amplifier circuit and high-frequency high-isolation DC/DC power supply circuit;

The bidirectional magnetic pulse isolation transmission circuit is respectively connected to the signal logic processing circuit, the device-level fault detection processing circuit and the signal reconstruction circuit in a bidirectional signal connection; the system-level fault detection processing circuit, the drive mode selection circuit, the fault type output circuit and the signal conversion interface The circuits are respectively connected with the signal logic processing circuit; the bidirectional magnetic pulse isolation transmission circuit is connected with the power operational amplifier circuit through the signal reconstruction circuit; the device level fault detection processing circuit is connected with the power operational amplifier circuit.

Preferably, the electrical signal real-time detection module includes a high-frequency power transformer primary current precision high-speed rectification circuit, an arc load current detection circuit and an arc load voltage real-time detection circuit.

Preferably, the fault diagnosis module includes an input overvoltage/undervoltage diagnosis circuit and an overheating diagnosis circuit.

Preferably, the power-frequency rectification and filtering module is connected to the WBG high-frequency converter module through a soft-start circuit module; the soft-start circuit module is also connected to the controller.

Preferably, the soft start circuit module includes a timing trigger U201, a relay RLY201, a relay RLY202, a current limiting resistor R201, and other peripheral auxiliary circuits.

The basic design principles of the utility model arc welding inverter are as follows: a new generation of ultra-high frequency WBG high-efficiency and high-power-density inverter technology is adopted to develop a new type of high-efficiency and high-power-density arc welding inverter; WGB high-frequency commutation Each WBG power device in the module, that is, WBG power device Q1, WBG power device Q2, WBG power device Q3, and WBG power device Q4, can use SiC devices or GaN devices, which have faster switching speed and lower switching loss , stronger pressure resistance and higher temperature resistance. In the utility model, the three-phase/single-phase AC input passes through the electromagnetic compatibility module and the power frequency rectification and filtering module to become a smooth direct current, and then enters the WBG high-frequency converter module, and then performs power transmission and transformation through the high-frequency power transformer , which flows into the high-frequency rectification and filtering module and is transformed into low-voltage direct current, which is provided to the arc load. At the same time, the electrical signal real-time detection module of the closed-loop control circuit detects the output current and voltage waveforms of the main circuit in real time, and simultaneously detects the primary side transient current waveform of the high-frequency power transformer; the electrical signal real-time detection module first detects The three-way electrical signal is pre-processed, and then input to the controller for closed-loop control on the one hand. At the same time, the real-time detection module of the electrical signal will also compare the processed primary side transient current signal with the preset over-current protection threshold. The comparison result is directly input to the WBG high-frequency drive and protection module to realize the mechanical advance protection of each WBG power device in the WBG high-frequency commutation module; the controller detects the electrical signal in real time according to the given information sent by the human-computer interaction module The sent electrical signal is processed according to the preset current-voltage double-closed-loop control algorithm to generate a corresponding PWM pulse width modulation given signal, which is input to the WBG high-frequency drive and protection module to generate the power of each WBG in the WBG high-frequency commutation module The PWM signal required for high-frequency/ultra-high frequency turn-on and turn-off of the device to obtain the required output waveform and its electrical characteristics; the electrical signal real-time detection module also transmits the processed main circuit output current and voltage signals to people The computer interaction module is used to display the real-time output of the arc welding inverter; the fault diagnosis module monitors the three-phase/single-phase AC input voltage value in real time to realize overvoltage and undervoltage monitoring, and also monitors the WBG high-frequency converter module in real time The actual temperature of the WBG power device and high-frequency power transformer realizes overheating monitoring; once a fault occurs, the fault diagnosis module will input the fault information into the controller to carry out the fault processing process, and at the same time connect the fault enable signal to the WBG high-frequency drive and The protection module turns off the PWM signal to realize the protection of the power circuit.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

1. The utility model arc welding inverter has higher power density and efficiency: due to the adoption of a new generation of high-efficiency WBG commutation technology, the efficiency can reach more than 95%, high efficiency and energy saving, compared with the current widely used IGBT and MOSFET arc Welded inverter, energy saving about 10%, power density increased by more than 30%, load duration rate up to 100%;

2. The utility model arc welding inverter has excellent dynamic response performance: the switching time of the WBG power device adopted can reach microsecond level, the inverter frequency can be as high as 500KHz or more, the time constant of the main circuit is very small, and the dynamic response performance Excellent, better welding process stability;

3. The utility model arc welding inverter has excellent process performance: because the utility model has higher inverter frequency, better dynamic performance and shorter control cycle, it is easier to realize the utility model to control the welding arc and the droplet Precise and fast regulation of dynamic behavior, easy to get better welding process quality;

4. The arc welding inverter of the utility model has better reliability and stability: because the WBG power device adopted in the utility model has lower switching loss and stronger high temperature resistance, it has better thermal stability and reliability At the same time, the utility model is equipped with a variety of fault detection and protection measures with mechanical advanced protection capabilities, so that the reliability of the utility model in the harsh arc welding environment is further guaranteed.

Description of drawings

Fig. 1 is a block diagram of the system principle of the utility model arc welding inverter;

Fig. 2 is a schematic diagram of the main circuit of the utility model arc welding inverter;

Fig. 3 is a schematic block diagram of the WBG high-frequency drive and protection module of the arc welding inverter of the present invention;

Fig. 4 is a circuit schematic diagram of the WBG high-frequency drive and protection module of the utility model arc welding inverter;

Fig. 5 is a schematic diagram of the electric signal real-time detection module of the utility model arc welding inverter;

Fig. 6 is a schematic diagram of the fault diagnosis module of the utility model arc welding inverter;

Fig. 7 is a schematic diagram of the man-machine interaction module of the utility model arc welding inverter;

Fig. 8 is a system principle block diagram of the arc welding inverter of the second embodiment;

Fig. 9 is a schematic diagram of the soft start circuit of the arc welding inverter in the second embodiment.

detailed description

The utility model is described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Embodiment one

As shown in Figures 1 to 7; high power density and high efficiency WBG arc welding inverter includes a main circuit and a closed-loop control circuit. The main circuit includes an electromagnetic compatibility module, a power frequency rectification and filtering module, a WBG high-frequency commutation module, a high-frequency power transformer and a high-frequency rectification and filtering module connected in sequence; the electromagnetic compatibility module is externally connected to a three-phase/single-phase AC input power supply, and the high The frequency rectification filter module is externally connected to the arc load.

The closed-loop control circuit includes an electrical signal real-time detection module, a human-computer interaction module, a fault diagnosis module, a controller, and a WBG high-frequency drive and protection module.

The WBG high-frequency drive and protection modules are respectively connected with the WBG high-frequency commutation module, fault diagnosis module, electrical signal real-time detection module and controller; the fault diagnosis module is also connected with three-phase/single-phase AC input power and WBG high-frequency commutation The module, the high-frequency power transformer and the controller are connected; the electrical signal real-time detection module is also connected with the high-frequency power transformer, the arc load, the controller and the human-computer interaction module; the human-computer interaction module is also connected with the controller.

The main circuit can adopt either a single-phase AC input power supply mode or a three-phase AC input power supply mode, either a half-bridge circuit or a full-bridge circuit. As shown in FIG. 2 , this embodiment only introduces a three-phase AC input power supply mode and a full bridge circuit as examples.

The WBG high-frequency commutation module includes WBG power device Q1, WBG power device Q2, WBG power device Q3, WBG power device Q4, freewheeling diode D7, freewheeling diode D8, freewheeling diode D9, freewheeling diode D10, capacitor C12, Capacitor C13, capacitor C14, capacitor C15, capacitor C16 and inductor Lr; high-frequency power transformer includes inductor Lm and transformer T1; high-frequency rectification and filtering module includes WBG power rectifier DR1, WBG power rectifier DR2, inductor Lo and capacitor C17.

The power frequency rectification filter module is connected in parallel with the series circuit composed of WBG power device Q1 and WBG power device Q3, and is connected in parallel with the series circuit composed of WBG power device Q2 and WBG power device Q4; On the device Q1; the freewheeling diode D8 and the capacitor C13 are respectively connected in parallel on the WBG power device Q2; the freewheeling diode D9 and the capacitor C14 are respectively connected in parallel on the WBG power device Q3; the freewheeling diode D10 and the capacitor C15 are respectively connected in parallel on the WBG power device Q4 Above; the connection point of WBG power device Q1 and WBG power device Q3 and the connection point of WBG power device Q2 and WBG power device Q are connected through the primary of transformer T1, capacitor C16 and inductor Lr; the inductor Lm is connected in parallel on the primary of transformer T1; The first output end of the transformer T1 secondary is connected to the second output end of the transformer T1 secondary through the WBG power rectifier DR1, the inductor Lo and the capacitor C17; and the connection point of the WBG power rectifier DR1 and the inductor Lo is connected through the WBG power rectifier DR2 is connected to the third output terminal of the secondary side of the transformer T1; the arc load R0 is connected in parallel with the capacitor C17.

In the main circuit, the three-phase AC input Ua, Ub, and Uc are connected to the electromagnetic compatibility module composed of common-mode inductor L _CMC , resistors R1-R6, and capacitors C1-C9 to suppress electromagnetic noise and electromagnetic pollution, and then enter the electromagnetic compatibility module composed of diode D1 -D6, inductance Lc and capacitors C10-C11 constitute the power frequency rectification and filtering module, which is converted into smooth high-voltage direct current. Then through the WBG high-frequency converter module, it is converted into a high-frequency/ultra-high-frequency square wave pulse waveform; the voltage waveform is passed through a high-frequency power transformer for power transmission, voltage conversion and electrical isolation, and an AC square wave pulse with a changed voltage value is obtained. Waveform; the voltage waveform is converted into the smooth direct current required by the process through the high-frequency rectification and filtering module, and output to the arc load R0. Capacitors C12-C15, inductor Lr, and capacitor C16 can be set to different values according to the working mode of the main circuit; WBG power devices Q1-Q4 and WBG power rectifiers DR1-DR2 can be SiC power devices, and can also be GaN power devices.

WBG high-frequency drive and protection module includes system-level fault detection processing circuit, power-level fault detection processing circuit, device-level fault detection processing circuit, drive mode selection circuit, fault type output circuit, bidirectional magnetic pulse isolation transmission circuit, signal logic processing circuit , Signal conversion interface circuit, signal reconstruction circuit, power operational amplifier circuit and high-frequency high-isolation DC/DC power supply circuit. The two-way magnetic pulse isolation transmission circuit is respectively connected to the signal logic processing circuit, the device-level fault detection processing circuit and the signal reconstruction circuit for two-way signal connection; the system-level fault detection processing circuit, the drive mode selection circuit, the fault type output circuit and the signal conversion interface circuit respectively It is connected with the signal logic processing circuit; the bidirectional magnetic pulse isolation transmission circuit is connected with the power operational amplifier circuit through the signal reconstruction circuit; the device level fault detection processing circuit is connected with the power operational amplifier circuit.

Specifically, the bidirectional magnetic pulse isolation transmission circuit is composed of high-frequency pulse transformers T401 and T402 of bidirectional double-wire wound low-leakage inductance structure. The signal logic processing circuit includes a signal interlock protection circuit, a differential circuit and a delay reset circuit. Among them, the signal interlock protection circuit includes resistors R400-R405, high-frequency weak current electrostatic protection diodes D401-D406 and NAND gate Schmitt trigger U401; the differential circuit includes MOSFET drive amplifier U403, capacitors C406-C409 and resistors R415- R416; the delayed reset circuit includes triodes Q401-Q405, resistors R407-R414, capacitors C401-C405 and monostable trigger U402.

The system-level fault detection processing circuit can be an existing inverter input voltage, current and power device temperature rise detection circuit; the power-level fault detection processing circuit can be an existing inverter output current and voltage signal detection feedback circuit; The device-level fault detection processing circuit may be an existing general fast voltage comparison circuit for detecting the transient turn-on voltage of a WBG power device. In addition, the signal conversion interface circuit, signal reconstruction circuit, power operational amplifier circuit, drive mode selection circuit, fault type output circuit and high-frequency high-isolation DC/DC power supply circuit can all use existing circuits.

The WBG high-frequency drive and protection module can work in both the half-bridge drive mode and the full-bridge drive mode, which is determined by the high and low level signals output by the drive mode selection circuit; the digital/analog PWM1 signal generated by the controller and The PWM2 signal is first converted into an electrical signal of a suitable voltage range through the signal interface circuit, and then enters the signal logic processing circuit to modulate the pulse signal with a wide range of duty ratio into a narrow pulse signal with a fixed width, and then based on the magnetic isolation type signal modulation principle , the two-way transmission and electrical insulation isolation are realized through the two-way magnetic pulse isolation transmission circuit through the pulse edge coupling method, and then the signal reconstruction circuit will be reconstructed according to the phase and logic relationship, and the desired driving power and driving waveform will be obtained through the power amplifier circuit; Since only a narrow pulse signal with a fixed width needs to be transmitted, the value of the magnetic core and winding of the bidirectional magnetic pulse isolation transmission circuit is very small, which not only avoids the magnetic saturation phenomenon that is easy to occur when the traditional transformer is driven, but also the leakage inductance and distributed capacitance are extremely small. Small, the waveform is not easy to oscillate when driven by a wide duty cycle, and the isolation effect is good, which effectively solves the problems of high-speed two-way transmission of signals and reliable isolation.

In order to improve the reliability and environmental adaptability of WBG power devices Q1-Q4 under severe welding conditions, the WBG high-frequency drive and protection module integrates a three-level mechanical advanced protection system including chip level, power level and system level. The system-level fault detection and processing circuit is mainly based on the under/overvoltage input by the fault diagnosis module, the overheating of power devices and high-frequency power transformers, and the output overcurrent and overvoltage detected by the electrical signal real-time detection module. Different level signals control the enablement of the signal logic processing circuit; the electrical signal real-time detection module detects the high-frequency power transformer primary side AC peak current waveform in real time, and compares it with the preset threshold after high-speed precision rectification. Value input power fault detection and processing circuit, and control the enabling of signal logic processing circuit; and chip-level detection mainly detects whether the WBG power device Q1-Q4 is instantaneous overcurrent/short circuit/overvoltage, once a corresponding fault occurs, it will directly control the power The operational amplifier circuit keeps it in the negative voltage waveform output state, directly turns off the WBG power device, reduces the processing delay of the intermediate link, and realizes real-time protection.

In order to ensure the driving reliability, stability and accuracy of the driving waveform, the WBG high-frequency driving and protection module in the utility model creatively adopts a 100kHz push-pull high-frequency isolated DC/DC module power supply circuit, which only needs two 24V single The power supply can meet all the power supply requirements of the drive, including the positive/negative drive waveforms required for the on/off of two high-power WBG power devices, the reference voltage source of the drive, and the power supply requirements of other components. The isolation withstand voltage exceeds 4500V.

The electrical signal real-time detection module includes three parts, namely the high-frequency power transformer primary current precision high-speed rectification circuit composed of resistors R300-R305, operational amplifiers U301-U302 and diodes D300-D303, and the circuit composed of resistors R306-R308 and capacitors C300- The arc load current detection circuit composed of C302, diodes D304-305 and operational amplifier U303, and the arc load voltage real-time detection circuit composed of resistors R309-R315, capacitors C303-C307, operational amplifiers U304-U306 and optocoupler U307, etc. Among them, I _p is the primary current signal of the high-frequency power transformer, I _o is the arc load current signal, and U _o is the voltage signal at both ends of the arc load; these three signals are all imported into the voltage signal converter U308 after processing, and then They are sent to the WBG high-frequency drive and protection module, controller and human-computer interaction module respectively.

The fault diagnosis module also mainly includes two parts, that is, input overvoltage/undervoltage composed of resistor R103, resistor R106, resistor R109, resistor R110, resistor R112, resistor R117, comparator U101, comparator U102, U104, capacitor C124 and capacitor C125. Voltage diagnosis circuit, and overheat diagnosis circuit composed of inductor L101, inductor L102, capacitor C126, capacitor C127, resistor R111, resistor R113, diode D101, diode D102, comparator U103, etc. Among them, VC is the voltage signal after the three-phase/unidirectional AC input voltage is step-down and rectified by the transformer, and the obtained divided voltage value enters the comparator U101 and U102 respectively through the series voltage division of the resistor R103/R109 and the resistor R106/R110 The non-inverting terminal and inverting terminal of the comparator are compared with the preset given value. If overvoltage and undervoltage occur, the output of comparators U101 and U102 will be reversed. Similarly, the overheat detection terminal is directly connected to the thermistor installed on the radiator of WBG power devices Q1-Q4 and the primary coil of the high-frequency power transformer. This resistor is connected in series with resistor R111 to divide the voltage; Change, so that the voltage of the inverting terminal of the comparator U103 changes, the voltage value is compared with the reference voltage value of the non-inverting terminal of the comparator U103, once the temperature rise exceeds the preset value, the output of the comparator U103 will reverse . The output signals of U104 and comparator U103 are transmitted to the controller and the WBG high-frequency drive and protection module respectively after passing through the inverter U105.

The controller can be an analog controller with SG3525, UC3846, UC3879 and other analog integrated PWM control signals as the core, or a digital controller with MCU, DSC and other microprocessors as the core; it can also use an analog integrated PWM control chip For the analog-digital hybrid controller combined with a microprocessor, this embodiment only introduces a controller with a DSC-level ARM microprocessor as an example. The controller is mainly composed of DSC-level ARM chip, chip power supply, ADC power supply, crystal oscillator circuit, reset circuit and JTAG modulation interface connected to each other through peripheral auxiliary circuits. The JTAG modulation interface mainly realizes the debugging function. The DSC-level ARM chip is the central processor of the entire control circuit and the core of digital control. The DSC-level ARM chip is embedded with a current-voltage double closed-loop control algorithm and its process control software, which can generate a variety of PWM digital signals required by different power commutation modes such as half-bridge, full-bridge, ZVS, and ZVZCS; complete output parameters and Digital closed-loop control of dynamic characteristics; can complete various process switching; receive various status information and fault signal processing; conduct human-computer interaction with the human-computer interaction module through the CAN or UART interface; and control various peripheral auxiliary devices through the GPIO port The action of a part or mechanism.

The human-computer interaction module can adopt key input + LED digital tube display mode, industrial touch screen human-computer interaction mode, or simple potentiometer + pointer instrument display. This embodiment only uses the mode of DSC microprocessor + industrial touch screen driver + industrial touch screen to introduce the principle. As shown in Figure 7, the human-computer interaction module has a three-level structure of "DSC+driver+touch screen", with the DSC-level ARM microprocessor as the control core to complete the centralized processing of various data; the industrial touch screen driver with built-in hardware acceleration function is used Chip, reduce data transmission time and resource occupation of DSC microprocessor, realize high-speed scanning and stable display of text/graphics on the touch screen; at the same time, use industrial-grade liquid crystal touch screen TFT-LCD as the human-computer interaction interface to realize intuitive information display and interaction. The human-computer interaction module also has a wealth of peripheral communication interfaces, including RS-232/485, SSI, CAN, etc., which can communicate with other devices in various ways; the human-computer interaction module expands the SD card interface and USB interface, Data storage and exchange can be realized conveniently; the human-computer interaction module also has its own ADC conversion module, which can directly receive and display the current and voltage signals output from the electrical signal real-time detection module without transferring them from the controller , so the real-time performance of information dynamic display will be stronger.

When the utility model is applied, the three-phase/single-phase power-frequency alternating current becomes smooth direct current after passing through the electromagnetic compatibility module and the power-frequency rectification and filtering module; Pulse waveform; through the high-frequency power transformer, it is transformed into a low-voltage high-frequency square wave pulse signal suitable for welding process requirements to achieve electrical isolation and power transmission; finally flows into the high-frequency rectification and filtering module to obtain a low-voltage high-current DC waveform. The controller compares the load current and voltage signals detected by the electrical signal real-time detection module with the welding parameters given by the human-computer interaction module, and processes them according to the preset control algorithm to generate the required PWM signal, which is passed through the WBG High-frequency drive and protection module isolation/power amplification to control the turn-on and turn-off of WBG power devices, so that the voltage waveform of the main circuit is converted into high-frequency high-voltage power after passing through the WBG high-frequency converter module, realizing closed-loop control. The fault diagnosis module detects the power frequency voltage value of the AC input, the temperature rise of the WBG power device and the temperature rise of the high-frequency power transformer, and the electrical signal real-time detection module detects the primary transient peak current of the high-frequency power transformer, and the detected The signals are sent to the controller and the WBG high-frequency drive and protection module respectively. Once input overvoltage, undervoltage, overheating or output overcurrent, overvoltage and other phenomena occur, the protection action of the WBG high-frequency drive and protection module is enabled and the PWM is turned off. The signal thus closes the opening of the WBG power device to ensure the safety of the main circuit.

Embodiment two

The difference between the high power density and high efficiency WBG arc welding inverter in this embodiment and the first embodiment is that in this embodiment, the power frequency rectification filter module and the WBG high frequency converter module are connected through a soft start circuit module; The starting circuit module is also connected with the controller, as shown in Fig. 8 and Fig. 9 . The soft start circuit module includes timing trigger U201, relay RLY201, relay RLY202, current limiting resistor R201, and other peripheral auxiliary circuits.

When the power supply is powered on, the three-phase/single-phase AC input starts to charge the electrolytic capacitor through the rectifier bridge and the high-power current limiting resistor R201; at the same time, the power signal VCC of the control board starts to charge the timing capacitor C207 through the timing resistor R211. After a short delay, the voltage of pin 2 of the timing trigger U201 is lower than the threshold voltage VCC/2, at this time, pin 3 outputs a high-level signal, the transistor Q201 starts to conduct, the action of relay RLY201 and relay RLY202 is closed, and the current limiting resistor R201 Bypassed, the rectified DC signal continues to charge the electrolytic capacitor and slowly reaches its rated value, and the power supply begins to work normally at this time. The RC element in the soft start circuit mainly plays the role of delay, and combined with the timing trigger U201 to form a monostable trigger circuit, which further improves the reliability and stability of the relay and ensures that the circuit can suppress the surge current more effectively. Prevent it from causing shock to the power supply.

The above-mentioned embodiment is a preferred implementation mode of the present utility model, but the implementation mode of the present utility model is not limited by the above-mentioned embodiment, and any other changes, modifications and substitutions made without departing from the spirit and principle of the present utility model , combination, and simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present utility model.

Claims (7)

1. A high-power-density high-efficiency WBG arc welding inverter is characterized in that: it comprises a main circuit and a closed-loop control circuit; Current module, high-frequency power transformer and high-frequency rectification and filtering module; Among them, the electromagnetic compatibility module is externally connected to three-phase/single-phase AC input power supply, and the high-frequency rectifying and filtering module is externally connected to arc load; The closed-loop control circuit includes an electrical signal real-time detection module, a human-computer interaction module, a fault diagnosis module, a controller, and a WBG high-frequency drive and protection module; The WBG high-frequency drive and protection module is respectively connected with the WBG high-frequency commutation module, fault diagnosis module, electrical signal real-time detection module and controller; the fault diagnosis module is also connected with three-phase/single-phase AC input power supply, WBG The high-frequency commutation module, the high-frequency power transformer and the controller are connected; the electrical signal real-time detection module is also connected with the high-frequency power transformer, the arc load, the controller and the human-computer interaction module respectively; the human-computer interaction module is also connected with the Controller connection. 2. The high power density and high efficiency WBG arc welding inverter according to claim 1, characterized in that: the WBG high frequency commutation module includes WBG power device Q1, WBG power device Q2, WBG power device Q3, WBG Power device Q4, freewheeling diode D7, freewheeling diode D8, freewheeling diode D9, freewheeling diode D10, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16 and inductor Lr; the high-frequency power transformer includes an inductor Lm and transformer T1; the high-frequency rectification filter module includes WBG power rectifier DR1, WBG power rectifier DR2, inductance Lo and capacitor C17; The power frequency rectification filter module is connected in parallel with the series circuit composed of WBG power device Q1 and WBG power device Q3, and is connected in parallel with the series circuit composed of WBG power device Q2 and WBG power device Q4; the freewheeling diode D7 and capacitor C12 are respectively connected in parallel WBG power device Q1; freewheeling diode D8 and capacitor C13 are respectively connected in parallel to WBG power device Q2; freewheeling diode D9 and capacitor C14 are respectively connected in parallel on WBG power device Q3; freewheeling diode D10 and capacitor C15 are respectively connected in parallel to WBG power On device Q4; the connection point of WBG power device Q1 and WBG power device Q3 and the connection point of WBG power device Q2 and WBG power device Q are connected through the primary of transformer T1, capacitor C16 and inductor Lr; the inductor Lm is connected in parallel to the primary of transformer T1 above; the first output terminal of the secondary of the transformer T1 is connected to the second output terminal of the secondary of the transformer T1 through the WBG power rectifier DR1, the inductor Lo and the capacitor C17; The rectifier DR2 is connected to the third output terminal of the secondary of the transformer T1; the arc load is connected in parallel with the capacitor C17. 3. The high power density and high efficiency WBG arc welding inverter according to claim 1, characterized in that: the WBG high frequency drive and protection module includes a system level fault detection processing circuit, a power level fault detection processing circuit, a device Level fault detection processing circuit, drive mode selection circuit, fault type output circuit, bidirectional magnetic pulse isolation transmission circuit, signal logic processing circuit, signal conversion interface circuit, signal reconstruction circuit, power operational amplifier circuit and high frequency high isolation DC/ DC power supply circuit; The bidirectional magnetic pulse isolation transmission circuit is respectively connected to the signal logic processing circuit, the device-level fault detection processing circuit and the signal reconstruction circuit in a bidirectional signal connection; the system-level fault detection processing circuit, the drive mode selection circuit, the fault type output circuit and the signal conversion interface The circuits are respectively connected with the signal logic processing circuit; the bidirectional magnetic pulse isolation transmission circuit is connected with the power operational amplifier circuit through the signal reconstruction circuit; the device level fault detection processing circuit is connected with the power operational amplifier circuit. 4. The high-power density and high-efficiency WBG arc welding inverter according to claim 1, characterized in that: said electrical signal real-time detection module includes a high-frequency power transformer primary current precision high-speed rectification circuit, and an arc load current detection circuit And arc load voltage real-time detection circuit. 5. The high power density and high efficiency WBG arc welding inverter according to claim 1, characterized in that: the fault diagnosis module includes an input overvoltage/undervoltage diagnosis circuit and an overheating diagnosis circuit. 6. The high power density and high efficiency WBG arc welding inverter according to claim 1, characterized in that: the power frequency rectification filter module and the WBG high frequency converter module are connected through a soft start circuit module; The soft start circuit module is also connected with the controller. 7. The high power density and high efficiency WBG arc welding inverter according to claim 6, characterized in that: the soft start circuit module includes a timing trigger U201, a relay RLY201, a relay RLY202, a current limiting resistor R201, and other Peripheral auxiliary circuits.