A flat-top pulse current generation device and control method for metal production

Abstract

This application relates to the field of pulsed power technology, and discloses a flat-top pulsed current generator and control method for metal fabrication. The control method corresponds to the flat-top pulsed current generator. The device includes a charging circuit, a main power circuit, a ripple compensation circuit, and an inductive load. The control method employs a structure combining a high-voltage energy storage circuit and a freewheeling energy feeding circuit, shortening the rise and fall edges while feeding back the energy stored in the metal load to the high-voltage energy storage circuit. During the flat-top phase of the metal load current, an H-bridge circuit provides initial compensation for the flat-top current; a linear regulating transistor provides more precise compensation; and by monitoring the real-time temperature of the metal, the repetition frequency required to stably maintain the metal at the target temperature under the set flat-top current amplitude and pulse width is dynamically calculated, ultimately generating a high-efficiency, low-ripple flat-top pulsed current.

Description

Technical Field

[0001] This application relates to the field of pulse power technology, specifically a flat-top pulse current generating device and control method for metal fabrication. Background Technology

[0002] Pulsed high-current technology is a novel processing method that utilizes instantaneous high-energy current pulses to treat metallic materials. Its core lies in applying a high-intensity current (peak values ​​reaching thousands to tens of thousands of amperes) within an extremely short time (typically on the order of microseconds to milliseconds), thereby achieving precise control over the microstructure and properties of the metal. Compared to traditional heat treatment processes, this technology boasts significant advantages such as concentrated energy, short processing time, small heat-affected zone, and energy efficiency, and has received widespread attention in the field of metal processing in recent years. The mechanism of pulsed high-current action on metallic materials is complex, mainly categorized into thermal effects and non-thermal effects. Thermal effects originate from the Joule heating generated when current passes through the metal; non-thermal effects include electroplasticity, which directly influences dislocation movement and grain boundary migration.

[0003] Traditional high-current pulsed power supplies often employ single-pulse capacitor discharge topologies to generate high current peaks, offering a simple structure and ease of implementation. However, due to the variable parameters of the metal load circuit during processing, such power supplies struggle to precisely control the peak value and width of the output pulse. Furthermore, because electroplasticity has a current density threshold, even slight deviations in the current peak value can lead to an uncontrolled ratio of thermal to non-thermal effects. Therefore, traditional power supplies cannot accurately verify the critical current and its duration required for the metal to undergo the target structural transformation. Moreover, limited by the coupling relationship between current peak value, pulse width, and output power, existing methods struggle to decouple thermal and non-thermal effects, making it impossible to separately study the impact of current peak value and load temperature on material processing.

[0004] Flat-top pulse power supplies, with their controllable rise / fall edges, flat-top amplitude, and width, are suitable as novel power sources for metal processing. Existing flat-top pulse power supplies typically employ H-bridge multilevel switching or IGBTs operating in the active region for compensation when maintaining the flat-top current. The H-bridge multilevel method aims to control the flat-top current fluctuation within a very small range, but the switching devices must switch at an extremely high frequency, resulting in significantly increased switching losses. Another method adjusts the drive voltage of the IGBT operating in the active region to precisely compensate for the difference between the target current and the actual current. While this method eliminates switching action and offers better current ripple performance than the H-bridge multilevel structure, the IGBT operating in the active region will bear a higher terminal voltage, resulting in greater power loss. Furthermore, due to lower efficiency, the repetition frequency of the flat-top pulse power supply is also lower, making it impossible to adjust the output power within a narrow repetition frequency range for precise metal temperature control. Therefore, existing flat-top pulse power supplies struggle to meet increasingly stringent application requirements, necessitating a flat-top pulse current generator that combines high efficiency and low ripple. Summary of the Invention

[0005] The purpose of this application is to provide a flat-top pulse current generating device and control method for metal preparation, so as to solve the technical problems in the prior art that it is difficult to reduce the loss of switching devices while improving the flatness of the pulse current, and it is difficult to achieve precise metal temperature control while meeting the set flat-top current amplitude and pulse width.

[0006] To achieve the above objectives, this application provides a flat-top pulse current generator for metal fabrication, comprising a charging circuit, a main power circuit, a ripple compensation circuit, and an inductive load, wherein the inductive load comprises at least a metal load; wherein the charging circuit comprises a high-voltage preamplifier circuit, a first low-voltage preamplifier circuit, and a second low-voltage preamplifier circuit; and the main power circuit comprises a high-voltage energy storage circuit, a low-voltage discharge circuit, and a freewheeling energy feeding circuit.

[0007] The first output terminal of the high-voltage preamplifier circuit and the output terminal of the freewheeling power supply circuit are both connected to the first input terminal of the high-voltage energy storage circuit; the second output terminal of the high-voltage preamplifier circuit is connected to the second input terminal of the high-voltage energy storage circuit; the first output terminal of the high-voltage energy storage circuit is connected to the first input terminal of the low-voltage discharge circuit; the first output terminal of the first low-voltage preamplifier circuit is connected to the second input terminal of the low-voltage discharge circuit; the second output terminals of the high-voltage energy storage circuit and the first low-voltage preamplifier circuit are both connected to the third input terminal of the low-voltage discharge circuit; the first output terminal of the second low-voltage preamplifier circuit is connected to the first input terminal of the ripple compensation circuit; the second output terminal of the second low-voltage preamplifier circuit is connected to the second input terminal of the ripple compensation circuit; the first output terminal of the ripple compensation circuit, the first output terminal of the low-voltage discharge circuit, and the second input terminal of the freewheeling power supply circuit are all connected to the positive terminal of the inductive load; the second output terminal of the ripple compensation circuit, the second output terminal of the low-voltage discharge circuit, and the first input terminal of the freewheeling power supply circuit are all connected to the negative terminal of the inductive load.

[0008] Preferably, the high-voltage preamplifier circuit includes a high-voltage charging power supply and a first charging switch; wherein, the positive terminal of the high-voltage charging power supply is connected to the positive terminal of the first charging switch, the negative terminal of the first charging switch is the first output terminal of the high-voltage preamplifier circuit, and the negative terminal of the high-voltage charging power supply is the second output terminal of the high-voltage preamplifier circuit.

[0009] Preferably, the first low-voltage preamplifier circuit includes a first low-voltage charging power supply and a second charging switch; wherein, the positive terminal of the first low-voltage charging power supply is connected to the positive terminal of the second charging switch, the negative terminal of the second charging switch is the first output terminal of the first low-voltage preamplifier circuit, and the negative terminal of the first low-voltage charging power supply is the second output terminal of the first low-voltage preamplifier circuit.

[0010] Preferably, the high-voltage energy storage circuit includes a high-voltage energy storage capacitor and a first IGBT; wherein, the positive terminal of the high-voltage energy storage capacitor is connected to the collector of the first IGBT, the emitter of the first IGBT is the first output terminal of the high-voltage energy storage circuit, and the negative terminal of the high-voltage energy storage capacitor is the second output terminal of the high-voltage energy storage circuit.

[0011] Preferably, the low-voltage discharge circuit includes a low-voltage energy storage capacitor, a first diode, an auxiliary inductor, and a second IGBT; wherein, the positive terminal of the low-voltage energy storage capacitor is connected to the anode of the first diode, the cathode of the first diode is connected to one end of the auxiliary inductor as the first input terminal of the low-voltage discharge circuit, the other end of the auxiliary inductor is the first output terminal of the low-voltage discharge circuit, the negative terminal of the low-voltage energy storage capacitor is connected to the collector of the second IGBT as the second input terminal of the low-voltage discharge circuit, and the emitter of the second IGBT is the second output terminal of the low-voltage discharge circuit.

[0012] Preferably, the freewheeling power supply circuit includes a second diode and a third diode; wherein, the anode of the second diode is the second input terminal of the freewheeling power supply circuit, the anode of the third diode is the first input terminal of the freewheeling power supply circuit, and the cathodes of the second diode and the third diode are connected to form the output terminal of the freewheeling power supply circuit.

[0013] Preferably, the second low-voltage preamplifier circuit includes a second low-voltage charging power supply and a third charging switch; wherein, the positive terminal of the second low-voltage charging power supply is connected to the positive terminal of the third charging switch, the negative terminal of the third charging switch is the first output terminal of the second low-voltage preamplifier circuit, and the negative terminal of the second low-voltage charging power supply is the second output terminal of the second low-voltage preamplifier circuit.

[0014] Preferably, the ripple compensation circuit includes an H-bridge circuit composed of four MOSFETs, a filter inductor, a third IGBT, and a fourth IGBT. One end of the filter inductor is connected to the midpoint of the leading arm of the H-bridge circuit, and the other end of the filter inductor, the emitter of the third IGBT, and the collector of the fourth IGBT are connected. The collector of the third IGBT is the first output terminal of the ripple compensation circuit, and the midpoint of the lagging arm of the H-bridge circuit and the emitter of the fourth IGBT are connected to form the second output terminal of the ripple compensation circuit.

[0015] Preferably, the flat-top pulse current generator is equipped with a corresponding control method, which includes:

[0016] Until the discharge begins, the high-voltage pre-amplifier circuit and the first low-voltage pre-amplifier circuit are controlled to charge the high-voltage energy storage circuit and the low-voltage discharge circuit respectively, and the second low-voltage pre-amplifier circuit is controlled to continuously charge the ripple compensation circuit.

[0017] During the discharge process: the high-voltage energy storage circuit is controlled to discharge to the metal load, causing the metal load current to rise rapidly; when the metal load current reaches the set value, the low-voltage discharge circuit is switched to discharge, entering the current flat-top stage; in the current flat-top stage, the ripple compensation circuit starts to work to maintain current stability.

[0018] After the set time is reached at the flat top stage, the low-voltage discharge circuit, ripple compensation circuit, and ripple compensation circuit are disconnected; the current of the inductive load is controlled to pass through the freewheeling energy feeding circuit to feed energy back to the high-voltage energy storage circuit, and the discharge process ends.

[0019] Preferably, the control method monitors the temperature of the metal load in real time and dynamically calculates the repetition frequency required to stably maintain the metal at the target temperature under the conditions of the preset flat-top current amplitude and pulse width set by the host computer.

[0020] Beneficial Effects: The flat-top pulse current generator and control method for metal fabrication presented in this application employ a structure combining a high-voltage energy storage circuit and a freewheeling energy feeding circuit. This significantly shortens the rise and fall times of the metal load current, while simultaneously feeding back the energy stored in the metal load to the high-voltage energy storage circuit. This effectively improves the control accuracy of the pulse current width and the overall energy utilization efficiency of the flat-top pulse current generator. During the flat-top phase of the metal load current, the H-bridge circuit in the ripple compensation circuit and the fourth IGBT jointly provide compensation current. By utilizing the IGBT operating in the active region and adjusting its driving voltage, precise control of the conduction current is achieved. This significantly reduces the ripple rate of the metal load current. In the ripple compensation circuit, the H-bridge circuit outputs the main compensation current, including the low-frequency ripple, to achieve initial compensation for the flat-top current. The fourth IGBT further outputs a small compensation current to offset the low-frequency ripple, thereby providing more precise compensation for the flat-top current. This structure not only effectively reduces the conduction current of the IGBT operating in the active region but also further improves the overall efficiency of the flat-top pulse current generator. While improving the overall efficiency of the flat-top pulse current generator, it also increases the repetition frequency adjustment range of the flat-top pulse current, providing key technical support for higher metal load temperature control accuracy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1A schematic block diagram of a flat-top pulsed current generator for metal fabrication provided in this application embodiment;

[0023] Figure 2 This is a circuit diagram of a flat-top pulse current generator for metal fabrication provided in an embodiment of this application.

[0024] Figure 3 Operating mode diagram of the charging stage of a flat-top pulse current generator for metal fabrication provided in the embodiments of this application;

[0025] Figure 4 The working mode diagram of the current rise phase of the flat-top pulse current generator for metal fabrication provided in the embodiments of this application;

[0026] Figure 5 Operating mode diagram of the flat-top current stage of the flat-top pulse current generator for metal fabrication provided in the embodiments of this application;

[0027] Figure 6 The working mode diagram of the current descent phase of the flat-top pulse current generator for metal fabrication provided in the embodiments of this application;

[0028] Figure 7 Typical waveform diagram of a flat-top pulse current generator for metal fabrication provided in the embodiments of this application;

[0029] Figure 8 A flowchart illustrating the control method for a flat-top pulse current generator for metal fabrication provided in this application embodiment;

[0030] Figure 9 A block diagram of metal temperature control for a flat-top pulsed current generator for metal fabrication provided in this application embodiment;

[0031] In the diagram: 10, charging circuit; 20, main power circuit; 30, ripple compensation circuit; 40, inductive load; 101, high-voltage preamplifier circuit; 102, first low-voltage preamplifier circuit; 103, second low-voltage preamplifier circuit; 201, high-voltage energy storage circuit; 202, low-voltage discharge circuit; 203, freewheeling power supply circuit.

[0032] The implementation, functional features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0034] In this document, the term "comprising" is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0035] To address the aforementioned technical problems, this embodiment provides a flat-top pulse current generator and control method for metal fabrication. The purpose is to: improve the flatness of the pulse current while reducing the losses of switching devices; and to achieve precise metal temperature control while meeting the set flat-top current amplitude and pulse width. In brief, this embodiment describes a flat-top pulse current generator and control method for metal fabrication: The device includes a charging circuit, a main power circuit, a ripple compensation circuit, and a metal load. The charging circuit consists of a high-voltage pre-amplifier circuit, a first low-voltage pre-amplifier circuit, and a second low-voltage pre-amplifier circuit. The main power circuit consists of a high-voltage energy storage circuit, a low-voltage discharge circuit, and a freewheeling power supply circuit. The ripple compensation circuit consists of an H-bridge circuit and a linear adjustment transistor. The control method corresponds to this flat-top pulse current generator. By employing a structure combining a high-voltage energy storage circuit and a freewheeling power supply circuit, the rising and falling edges are shortened while the energy stored in the metal load is fed back to the high-voltage energy storage circuit. During the flat-top phase of the metal load current, the H-bridge circuit outputs a main compensation current containing low-frequency ripple, achieving initial compensation for the flat-top current. The linear adjustment transistor further outputs a small compensation current to offset the low-frequency ripple, thereby providing more refined compensation for the flat-top current. Simultaneously, by monitoring the real-time temperature of the metal, the repetition frequency required to stably maintain the metal at the target temperature under the conditions of setting the flat-top current amplitude and pulse width is dynamically calculated. Through the above, a high-efficiency, low-ripple flat-top pulse current is ultimately generated.

[0036] Reference Figure 1 , Figure 1 A schematic block diagram of a flat-top pulsed current generator for metal fabrication provided in this application embodiment.

[0037] like Figure 1As shown, this embodiment discloses a flat-top pulse current generator for metal fabrication, including a charging circuit 10, a main power circuit 20, a ripple compensation circuit 30, and an inductive load 40, the inductive load including at least a metal load; wherein, the charging circuit 10 includes a high-voltage preamplifier circuit 101, a first low-voltage preamplifier circuit 102, and a second low-voltage preamplifier circuit 103; the main power circuit 20 includes a high-voltage energy storage circuit 201, a low-voltage discharge circuit 202, and a freewheeling energy feeding circuit 203.

[0038] The first output terminal of the high-voltage preamplifier circuit 101 and the output terminal of the freewheeling power supply circuit 203 are both connected to the first input terminal of the high-voltage energy storage circuit 201; the second output terminal of the high-voltage preamplifier circuit 101 is connected to the second input terminal of the high-voltage energy storage circuit 201; the first output terminal of the high-voltage energy storage circuit 201 is connected to the first input terminal of the low-voltage discharge circuit 202; the first output terminal of the first low-voltage preamplifier circuit 102 is connected to the second input terminal of the low-voltage discharge circuit 202; the second output terminals of the high-voltage energy storage circuit 201 and the first low-voltage preamplifier circuit 102 are both connected to the low-voltage discharge circuit 202. The third input terminal is connected; the first output terminal of the second low-voltage preamplifier circuit 103 is connected to the first input terminal of the ripple compensation circuit 30; the second output terminal of the second low-voltage preamplifier circuit 103 is connected to the second input terminal of the ripple compensation circuit 30; the first output terminal of the ripple compensation circuit 30, the first output terminal of the low-voltage discharge circuit 202, and the second input terminal of the freewheeling power supply circuit 203 are all connected to the positive terminal of the inductive load 40; the second output terminal of the ripple compensation circuit 30, the second output terminal of the low-voltage discharge circuit 202, and the first input terminal of the freewheeling power supply circuit 203 are all connected to the negative terminal of the inductive load 40.

[0039] Reference Figure 2 , Figure 2 The circuit diagram is provided for a flat-top pulse current generator for metal fabrication according to an embodiment of this application.

[0040] like Figure 2 As shown, the high-voltage front-end circuit 101 includes a high-voltage charging power supply and a first charging switch. Among them, the positive terminal of the high-voltage charging power supply is connected to the first charging switch. The positive terminal is connected, and the first charging switch is activated. The negative terminal of the high-voltage preamplifier circuit 101 is the first output terminal, and the negative terminal of the high-voltage charging power supply is the second output terminal of the high-voltage preamplifier circuit 101; the high-voltage preamplifier circuit 101 is used to power the high-voltage energy storage capacitor in the high-voltage energy storage circuit 201. Charging. It should be noted that the inductive load in this embodiment can be a corresponding metallic load. Figure 2 In this context, the metallic load is equivalent to a resistor. and inductor .

[0041] like Figure 2 As shown, the first low-voltage preamplifier circuit 102 includes a first low-voltage charging power supply and a second charging switch. Among them, the positive terminal of the first low-voltage charging power supply is connected to the second charging switch. Connect the positive terminal to the second charging switch. The negative terminal of the first low-voltage preamplifier circuit 102 is the first output terminal, and the negative terminal of the first low-voltage charging power supply is the second output terminal of the first low-voltage preamplifier circuit 102; the first low-voltage preamplifier circuit 102 is used to charge the low-voltage discharge capacitor in the low-voltage discharge circuit 202. Charge.

[0042] like Figure 2 As shown, the high-voltage energy storage circuit 201 includes a high-voltage energy storage capacitor. And the first IGBT Among them, high-voltage energy storage capacitors The positive electrode and the first IGBT The collectors of the first IGBT are connected. The transmitter is the first output terminal of the high-voltage energy storage circuit 201, and the high-voltage energy storage capacitor is... The negative terminal is the second output terminal of the high-voltage energy storage circuit 201; the high-voltage energy storage circuit 201 is used to accelerate the rise or fall of the flat-top current of the inductive load 40, thereby achieving precise control of the pulse current width.

[0043] like Figure 2 As shown, the low-voltage discharge circuit 202 includes a low-voltage energy storage capacitor. First diode Auxiliary inductor Second IGBT Among them, low-voltage energy storage capacitors The positive terminal and the first diode The anode of the first diode is connected. Cathode and auxiliary inductor One end is connected to the first input terminal of the low-voltage discharge circuit 202, and the auxiliary inductor The other end is the first output terminal of the low-voltage discharge circuit 202, and the low-voltage energy storage capacitor. The negative electrode and the second IGBT The collector of the second IGBT is connected to the second input terminal of the low-voltage discharge circuit 202. The emitter is the second output terminal of the low-voltage discharge circuit 202; the low-voltage energy storage capacitor in the low-voltage discharge circuit 202 It handled the main power delivery during the 40kWh flat-top phase of the inductive load, and the initial value of the capacitor voltage and the equivalent resistance of the load. With the set flat-top current magnitude The product of these factors is close to the value of the current, which greatly reduces the current required by the subsequent compensation circuit.

[0044] like Figure 2 As shown, the freewheeling power supply circuit 203 includes a second diode. and the third diode Among them, the second diode The anode is the second input terminal of the freewheeling power supply circuit 203, and the third diode... The anode is the first input terminal of the freewheeling power supply circuit 203, and the second diode... cathode and third diode The cathode is connected to the output terminal of the freewheeling power supply circuit 203; the freewheeling power supply circuit 203 converts the metal load current of the inductive load 40 Energy is fed back to the high-voltage energy storage circuit 201, which improves the energy utilization rate of the flat-top current generator.

[0045] like Figure 2 As shown, the second low-voltage preamplifier circuit 103 includes a second low-voltage charging power supply and a third charging switch. Among them, the positive terminal of the second low-voltage charging power supply is connected to the third charging switch. Connect the positive terminal to the third charging switch. The negative terminal of the second low-voltage preamplifier circuit 103 is the first output terminal of the second low-voltage charging power supply, and the negative terminal of the second low-voltage preamplifier circuit 103 is the second output terminal of the second low-voltage preamplifier circuit 103; the second low-voltage preamplifier circuit 103 is used as the input power supply of the ripple compensation circuit 30.

[0046] like Figure 2 As shown, the ripple compensation circuit 30 includes four MOSFETs. to The H-bridge circuit and filter inductor are composed of Third IGBT and the fourth IGBT Among them, the filter inductor One end is connected to the midpoint A of the leading arm of the H-bridge circuit, and the filter inductor The other end, the third IGBT The emitter and the fourth IGBT The collectors are connected, and the third IGBT is connected. The collector is the first output terminal of the ripple compensation circuit 30. The H-bridge circuit lags the midpoint B of the bridge arm and the fourth IGBT. The emitter is connected to the second output terminal of the ripple compensation circuit 30; the ripple compensation circuit 30 is used to compensate for the metal load current during the flat-top phase. and setting the flat top current The difference between them is used to maintain current stability; the output current of the ripple compensation circuit 30 is determined by the H-bridge circuit and the fourth IGBT. The circuit consists of two parts: the H-bridge circuit is responsible for outputting most of the compensation current with low-frequency ripple. The fourth IGBT Responsible for outputting a small portion of the compensation current to offset low-frequency ripple current. This significantly reduces the ripple rate of the metal load current and the conduction current of the IGBT operating in the active region, thereby improving the efficiency of the flat-top pulse current generator.

[0047] Reference Figures 3 to 6 , Figures 3 to 6 The diagrams show the various operating modes of the flat-top pulsed current generator for metal fabrication provided in the embodiments of this application.

[0048] Reference Figure 7 , Figure 7 A typical waveform diagram of a flat-top pulsed current generator for metal fabrication provided in the embodiments of this application.

[0049] exist Figure 3 In the middle, it represents the charging stage before the inductive load is discharged (40). Figure 7 In Until discharge begins, the high-voltage preamplifier circuit 101 and the first low-voltage preamplifier circuit 102 charge the high-voltage energy storage circuit 201 and the low-voltage discharge circuit 202 respectively, while the second low-voltage preamplifier circuit 103 continuously charges the ripple compensation circuit 30; at this time , , Conductive, to , to Turn off.

[0050] exist Figure 4 In the middle, it represents the rising phase of the current, corresponding to Figure 7 In In this stage, the high-voltage energy storage circuit 201 is first controlled to discharge to the inductive load 40, causing the metallic load current of the inductive load 40 to... Rising rapidly; at this time , Turn off, Conductive, , Conductive, , Turn off, to Turn off.

[0051] When the metal load current Reaching the set value Then, it switches to the low-voltage discharge circuit 202 for discharge, entering... Figure 5The flat-top current stage shown corresponds to Figure 7 In ;at this time , Turn off, Conductive, Turn off, , , Conductive, / , / Alternating switching; during the flat-top current phase, the ripple compensation circuit 30 starts working to maintain the current. Stable; ripple compensation circuit 30 consists of MOSFETs to The H-bridge circuit and the fourth IGBT It consists of two parts: based on the set current. With actual current The difference is used to adjust the switching frequency and duty cycle of the H-bridge circuit, thereby controlling the voltage across the filter inductor and outputting most of the compensation current with low-frequency ripple. This serves as initial compensation for the flat-top current; further, the output voltage of the linear drive is adjusted by the controller, i.e., the fourth IGBT in the ripple compensation circuit. The driving voltage causes it to output a small compensation current that cancels out the low-frequency ripple current. This allows for more precise compensation of the flat-top current.

[0052] exist Figure 6 In the middle, during the current decrease phase, corresponding to Figure 7 In ;at this time Conductive, , , to , to Shutdown; after reaching the flat-top stage for a set time, disconnect the low-voltage discharge circuit 202 and the ripple compensation circuit 30; control the metal load current. Energy is fed back to the high-voltage energy storage circuit 201 through the freewheeling power supply circuit 203 to realize the metal load current. The discharge process ends after a rapid descent.

[0053] like Figure 7 The figures show the drive signals for the switching devices and the metal load current in the flat-top pulse current generator, respectively. Fourth IGBT On current H-bridge circuit current The compensation current of a single IGBT when using only IGBT as the ripple compensation circuit shows that the structure combining the high-voltage energy storage circuit 201 and the freewheeling power supply circuit 203 significantly shortens the metal load current. The rise and fall times; and the flat-top current stage, under the compensation of the ripple compensation circuit 30, the metal load current. The ripple rate is significantly reduced; at the same time, compared with using only IGBT as the ripple compensation circuit, the IGBT operating in the active region... The conduction current is much smaller than the compensation current of a single IGBT when using IGBT as the ripple compensation circuit, thereby further improving the overall efficiency of the flat-top pulse current generator.

[0054] Reference Figure 8 , Figure 8 A flowchart illustrating the control method for a flat-top pulse current generator for metal fabrication provided in this application embodiment.

[0055] like Figure 8 As shown, this embodiment discloses a control method for a flat-top pulse current generator for metal fabrication, including the following steps:

[0056] S10: Until discharge begins, control the high-voltage front-end circuit and the first low-voltage front-end circuit to charge the high-voltage energy storage circuit and the low-voltage discharge circuit respectively, and control the second low-voltage front-end circuit to continuously charge the ripple compensation circuit.

[0057] S20: During the discharge process: the high-voltage energy storage circuit is controlled to discharge to the metal load, causing the metal load current to rise rapidly; when the metal load current reaches the set value, the low-voltage discharge circuit is switched to discharge, entering the current flat-top stage; in the current flat-top stage, the ripple compensation circuit starts to work to maintain current stability.

[0058] S30: After the set time is reached at the flat top stage, disconnect the low-voltage discharge circuit, ripple compensation circuit, and ripple compensation circuit; control the current of the inductive load to feed energy back to the high-voltage energy storage circuit through the freewheeling energy feeding circuit, and the discharge process ends.

[0059] In the specific application of this embodiment, the ripple compensation circuit starts working to maintain current stability, including:

[0060] The ripple compensation circuit consists of two parts: an H-bridge circuit and a fourth IGBT. Based on the difference between the set current and the actual current, the switching frequency and duty cycle of the H-bridge circuit are adjusted to control the voltage across the filter inductor, thereby outputting most of the compensation current with low-frequency ripple as preliminary compensation for the flat-top current. Furthermore, the output voltage of the linear drive, i.e. the drive voltage of the fourth IGBT in the ripple compensation circuit, is adjusted by the controller to make it output a small portion of the compensation current that cancels out the low-frequency ripple current, thus providing further fine compensation for the flat-top current.

[0061] Specifically, by monitoring the temperature of the metal load in real time, and under the conditions of the flat-top current amplitude and pulse width set by the host computer, the repetition frequency required to stably maintain the metal at the target temperature is dynamically calculated.

[0062] Reference Figure 9 , Figure 9 A block diagram of metal temperature control for a flat-top pulsed current generator for metal fabrication provided in an embodiment of this application.

[0063] like Figure 9 As shown, The host computer sends the metal set temperature to the controller. Set the current for the flat-top pulse current sent from the host computer to the controller. The set pulse width is sent from the host computer to the controller. The repetition frequency of the flat-top pulse current. This refers to the output power of the flat-top pulse current generator. This is the actual temperature of the metal. For example... Figure 5 As shown, the metal set temperature is issued by the host computer. With the actual temperature of the metal The difference is calculated and sent to the feedback controller, where the current is set by the flat-top pulse current sent by the host computer. and setting pulse width The summation is fed into the feedforward controller, and the difference between the outputs of the feedback controller and the feedforward controller generates the repetition frequency of the flat-top pulse current. f By controlling the flat-top pulse current generator to produce pulse power And it acts on the metal load, causing the actual temperature of the metal to rise. Stabilize at the metal set temperature set by the host computer Because the flat-top pulse current generator proposed in this invention has high efficiency, the adjustable range of the flat-top pulse current repetition frequency is also large, thereby enabling better control of the temperature of the metal load.

[0064] In summary, the flat-top pulse current generating device and control method for metal fabrication described in this embodiment have at least the following advantages compared with the prior art:

[0065] 1. This embodiment adopts a structure that combines a high-voltage energy storage circuit and a freewheeling energy feeding circuit, which significantly shortens the rise and fall time of the metal load current. At the same time, the energy stored in the metal load is fed back to the high-voltage energy storage circuit, thereby effectively improving the control accuracy of the pulse current width and the overall energy utilization efficiency of the flat-top pulse current generator.

[0066] 2. During the flat-top phase of the metal load current, the H-bridge circuit in the ripple compensation circuit and the fourth IGBT jointly provide compensation current. By utilizing the IGBT operating in the active region and adjusting its drive voltage, the conduction current is precisely controlled, thereby significantly reducing the ripple rate of the metal load current.

[0067] 3. In the ripple compensation circuit, the H-bridge circuit outputs the main compensation current, including the low-frequency ripple, to achieve initial compensation for the flat-top current. The fourth IGBT further outputs a small compensation current to offset the low-frequency ripple, thereby providing more precise compensation for the flat-top current. This structure not only effectively reduces the on-state current of the IGBT operating in the active region but also further improves the overall efficiency of the flat-top pulse current generator.

[0068] 4. While improving the overall efficiency of the flat-top pulse current generator, it also increases the repetition frequency adjustment range of the flat-top pulse current, providing key technical support for higher temperature control accuracy of metal loads.

[0069] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flat-top pulse current generation device for metal production, characterized by, It includes a charging circuit, a main power circuit, a ripple compensation circuit, and an inductive load, the inductive load including at least a metallic load; wherein, the charging circuit includes a high-voltage preamplifier circuit, a first low-voltage preamplifier circuit, and a second low-voltage preamplifier circuit; the main power circuit includes a high-voltage energy storage circuit, a low-voltage discharge circuit, and a freewheeling energy supply circuit. The first output terminal of the high-voltage preamplifier circuit and the output terminal of the freewheeling power supply circuit are both connected to the first input terminal of the high-voltage energy storage circuit; the second output terminal of the high-voltage preamplifier circuit is connected to the second input terminal of the high-voltage energy storage circuit; the first output terminal of the high-voltage energy storage circuit is connected to the first input terminal of the low-voltage discharge circuit; the first output terminal of the first low-voltage preamplifier circuit is connected to the second input terminal of the low-voltage discharge circuit; the second output terminals of the high-voltage energy storage circuit and the first low-voltage preamplifier circuit are both connected to the third input terminal of the low-voltage discharge circuit; the first output terminal of the second low-voltage preamplifier circuit is connected to the first input terminal of the ripple compensation circuit; the second output terminal of the second low-voltage preamplifier circuit is connected to the second input terminal of the ripple compensation circuit; the first output terminal of the ripple compensation circuit, the first output terminal of the low-voltage discharge circuit, and the second input terminal of the freewheeling power supply circuit are all connected to the positive terminal of the inductive load; the second output terminal of the ripple compensation circuit, the second output terminal of the low-voltage discharge circuit, and the first input terminal of the freewheeling power supply circuit are all connected to the negative terminal of the inductive load. The low-voltage discharge circuit includes a low-voltage energy storage capacitor, a first diode, an auxiliary inductor, and a second IGBT. The positive terminal of the low-voltage energy storage capacitor is connected to the anode of the first diode, the cathode of the first diode is connected to one end of the auxiliary inductor as the first input terminal of the low-voltage discharge circuit, the other end of the auxiliary inductor is the first output terminal of the low-voltage discharge circuit, the negative terminal of the low-voltage energy storage capacitor is connected to the collector of the second IGBT as the second input terminal of the low-voltage discharge circuit, and the emitter of the second IGBT is the second output terminal of the low-voltage discharge circuit.

2. The flat-top pulse current generation device for metal production according to claim 1, characterized by, The high-voltage preamplifier circuit includes a high-voltage charging power supply and a first charging switch; wherein, the positive terminal of the high-voltage charging power supply is connected to the positive terminal of the first charging switch, the negative terminal of the first charging switch is the first output terminal of the high-voltage preamplifier circuit, and the negative terminal of the high-voltage charging power supply is the second output terminal of the high-voltage preamplifier circuit.

3. The flat-top pulse current generation device for metal fabrication of claim 1, wherein, The first low-voltage preamplifier circuit includes a first low-voltage charging power supply and a second charging switch; wherein, the positive terminal of the first low-voltage charging power supply is connected to the positive terminal of the second charging switch, the negative terminal of the second charging switch is the first output terminal of the first low-voltage preamplifier circuit, and the negative terminal of the first low-voltage charging power supply is the second output terminal of the first low-voltage preamplifier circuit.

4. The flat-top pulse current generation device for metal fabrication of claim 1, wherein, The high-voltage energy storage circuit includes a high-voltage energy storage capacitor and a first IGBT; wherein, the positive terminal of the high-voltage energy storage capacitor is connected to the collector of the first IGBT, the emitter of the first IGBT is the first output terminal of the high-voltage energy storage circuit, and the negative terminal of the high-voltage energy storage capacitor is the second output terminal of the high-voltage energy storage circuit.

5. The flat-top pulse current generation device for metal fabrication of claim 1, wherein, The freewheeling power supply circuit includes a second diode and a third diode; wherein, the anode of the second diode is the second input terminal of the freewheeling power supply circuit, the anode of the third diode is the first input terminal of the freewheeling power supply circuit, and the cathodes of the second diode and the third diode are connected to form the output terminal of the freewheeling power supply circuit.

6. The flat-top pulsed current generator for metal fabrication according to claim 1, characterized in that, The second low-voltage preamplifier circuit includes a second low-voltage charging power supply and a third charging switch; wherein, the positive terminal of the second low-voltage charging power supply is connected to the positive terminal of the third charging switch, the negative terminal of the third charging switch is the first output terminal of the second low-voltage preamplifier circuit, and the negative terminal of the second low-voltage charging power supply is the second output terminal of the second low-voltage preamplifier circuit.

7. The flat-top pulsed current generator for metal fabrication according to claim 1, characterized in that, The ripple compensation circuit includes an H-bridge circuit composed of four MOSFETs, a filter inductor, a third IGBT, and a fourth IGBT. One end of the filter inductor is connected to the midpoint of the leading arm of the H-bridge circuit, and the other end of the filter inductor, the emitter of the third IGBT, and the collector of the fourth IGBT are connected. The collector of the third IGBT is the first output terminal of the ripple compensation circuit, and the midpoint of the lagging arm of the H-bridge circuit and the emitter of the fourth IGBT are connected to form the second output terminal of the ripple compensation circuit.

8. A control method for a flat-top pulse current generator for metal fabrication, applicable to the flat-top pulse current generator as described in any one of claims 1 to 7, characterized in that, The flat-top pulse current generator is equipped with a corresponding control method, which includes: Until the discharge begins, the high-voltage pre-amplifier circuit and the first low-voltage pre-amplifier circuit are controlled to charge the high-voltage energy storage circuit and the low-voltage discharge circuit respectively, and the second low-voltage pre-amplifier circuit is controlled to continuously charge the ripple compensation circuit. During the discharge process: the high-voltage energy storage circuit is controlled to discharge to the metal load, causing the metal load current to rise rapidly; when the metal load current reaches the set value, the low-voltage discharge circuit is switched to discharge, entering the current flat-top stage; during the current flat-top stage, the ripple compensation circuit starts to work to maintain current stability. After the set time is reached at the flat top stage, the low-voltage discharge circuit, ripple compensation circuit, and ripple compensation circuit are disconnected; the current of the inductive load is controlled to pass through the freewheeling energy feeding circuit to feed energy back to the high-voltage energy storage circuit, and the discharge process ends.

9. The control method for the flat-top pulse current generator for metal fabrication according to claim 8, characterized in that, The control method monitors the temperature of the metal load in real time and dynamically calculates the repetition frequency required to stably maintain the metal at the target temperature under the conditions of the preset flat-top current amplitude and pulse width set by the host computer.

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