High-precision push-pull IGBT pulse driving circuit device based on analog differential PI

Abstract

The application relates to a high-precision push-pull IGBT pulse driving circuit device based on analog differential PI, and belongs to the technical field of power electronic driving circuits. The device comprises a main power switch loop, a reference voltage inverse pressure amplification module, a sampling voltage proportional amplification module, a differential input PI closed loop error adjustment module and a complementary push-pull power driving output module. The application solves the problems of reference signal temperature drift, large steady-state error, insufficient gate driving load capacity and lack of hardware lockout protection in the prior art, and realizes 100A-400A wide-range high-precision pulse constant current output.

Description

Technical Field

[0001] This application relates to the field of power electronic drive circuit technology, and in particular to a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI. Background Technology

[0002] In the fields of pulse power, semiconductors, xenon lamp pulse power supplies, and small-to-medium power conversion, the control accuracy, steady-state output stability, and anti-interference capability of IGBT pulse drive circuits are the core factors determining the overall equipment's performance and lifespan. Conventional simple open-loop drive circuits rely solely on a fixed voltage level to directly drive power devices, lacking a real-time current closed-loop correction mechanism. When load resistance or input voltage fluctuates, the circuit output current will exhibit significant fluctuations, easily leading to overcurrent and undercurrent conditions, failing to meet the stringent constant current control requirements of high-precision pulse output equipment.

[0003] As the operating frequency of pulse devices increases and the output current range widens, the electromagnetic interference from switching and the power supply ripple interference experienced by the drive circuit continue to intensify. Traditional single operational amplifier simple drive circuits lack graded signal shaping and impedance matching structures, and the reference signal and sampling feedback signal are prone to amplitude drift and waveform distortion, causing IGBT switching timing offset and output pulse flat-top collapse, which greatly reduces the consistency of pulse output. Utility Model Content

[0004] The purpose of this application is to provide a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, so as to solve the technical problems existing in the prior art, such as reference signal temperature drift, large steady-state output deviation, insufficient gate drive load capacity, switching crossover oscillation, weak anti-interference capability, and lack of hardware-level fault protection.

[0005] The solution presented in this application example is implemented through the following steps.

[0006] This application discloses an example of a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, including a main power switching circuit, and further comprising: The reference voltage inverting amplifier module is used to receive an external reference voltage, perform inverting proportional amplification and impedance buffering on the reference voltage, and output a reference electrical signal. The sampling voltage proportional amplifier module is connected to the main power switch circuit signal and is used to receive the current sampling voltage across the sampling element in the main power switch circuit, perform waveform shaping and amplitude matching processing on the current sampling voltage, and output a sampling feedback signal. The differential input PI closed-loop error adjustment module is connected to the reference voltage reverse voltage amplification module and the sampling voltage proportional amplification module respectively. It is used to perform differential operation on the reference electrical signal and the sampling feedback signal, and output the error control voltage after being corrected by the proportional-integral composite compensation network. The complementary push-pull power drive output module is signal-connected to the differential input PI closed-loop error adjustment module. It is used to expand the current capacity and amplify the power of the error control voltage, generate a gate drive signal and output it to the main power switching circuit to control the on and off of the main power switching device. The main power switching circuit includes a main power switching device, a load, and a sampling element connected in series. The two ends of the sampling element are connected to the sampling voltage proportional amplifier module to form an analog closed-loop feedback link.

[0007] By coordinating four modules—a reference voltage reverse voltage amplification module, a sampling voltage proportional amplification module, a differential input PI closed-loop error adjustment module, and a complementary push-pull power drive output module—a pure analog current closed-loop control system is formed. This system eliminates the need for digital control chips and achieves high-precision constant current output under a wide pulse current range of 100A to 400A. It also solves multiple technical problems such as reference signal temperature drift, large steady-state output deviation, insufficient gate drive load capacity, switch crossover oscillation, weak anti-interference capability, and lack of hardware-level fault protection. The output waveform is flat, the timing is stable, and the steady-state error is extremely low.

[0008] As described above, in the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, optionally, the reference voltage reverse voltage amplification module includes a first precision operational amplifier, an input current-limiting resistor, a feedback amplification resistor, a non-inverting input balancing resistor, and a filter capacitor; wherein, One end of the input current-limiting resistor receives an external reference voltage, and the other end is electrically connected to the inverting input terminal of the first precision operational amplifier. The feedback amplification resistor is electrically connected between the inverting input terminal and the output terminal of the first precision operational amplifier; The non-inverting input balancing resistor is electrically connected between the non-inverting input of the first precision operational amplifier and ground. The filter capacitor is electrically connected between the power supply pin of the first precision operational amplifier and ground.

[0009] By setting a first precision operational amplifier, an input current-limiting resistor, a feedback amplification resistor, a non-inverting input balancing resistor, and a filter capacitor in the reference voltage inverting amplification module, an inverting proportional amplification topology is formed, achieving impedance isolation and precise amplitude scaling of the external reference voltage. The low temperature drift characteristic of the precision operational amplifier (typical value 0.2 μV / ℃) effectively suppresses the amplitude drift of the reference signal caused by temperature changes. The non-inverting input balancing resistor R3 is matched with the equivalent impedance of the inverting input, eliminating the output DC deviation caused by bias current asymmetry. The filter capacitor decouples nearby, suppressing the influence of power supply ripple on the reference accuracy, and providing a low-drift, high-stability given reference quantity for the differential input PI closed-loop error adjustment module.

[0010] As described above, in the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, optionally, the sampling voltage proportional amplification module includes a second precision operational amplifier, a proportional feedback resistor, a non-inverting input balancing resistor, and a filter capacitor; the second precision operational amplifier constitutes an inverting proportional amplification topology; wherein... The proportional feedback resistor is electrically connected between the inverting input terminal and the output terminal of the second precision operational amplifier; The non-inverting input balancing resistor is electrically connected between the non-inverting input of the second precision operational amplifier and ground. The filter capacitor is electrically connected between the power supply pin of the second precision operational amplifier and ground.

[0011] By setting a second precision operational amplifier, a proportional feedback resistor R4, a non-inverting input balancing resistor R5, and filter capacitors C7 and C8 in the sampling voltage proportional amplifier module, an inverting proportional amplifier topology is formed. This amplifies the millivolt-level weak current sampling voltage in the main power circuit to a level that matches the amplitude range of the reference electrical signal. The non-inverting input balancing resistor R5 eliminates the DC deviation caused by bias current asymmetry. The filter capacitors nearby decouple and filter out the pollution of the sampling waveform by high current switching noise, effectively solving the problem that weak sampling signals are easily submerged by noise, and ensuring that the differential input PI closed-loop error adjustment module obtains accurate and stable feedback.

[0012] As described above, the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI can optionally include a differential input PI closed-loop error adjustment module comprising an operational amplifier, a differential symmetrical input resistor group, a non-inverting input grounding balancing resistor, a proportional feedback resistor, an integrating series resistor, and an integrating capacitor; wherein, The differential symmetrical input resistor group is electrically connected to the inverting input terminal and the non-inverting input terminal of the operational amplifier, respectively, and is used to introduce the reference electrical signal and the sampling feedback signal in a symmetrical impedance manner. The proportional feedback resistor, the integral series resistor, and the integral capacitor are connected in series to form a proportional-integral composite compensation network, which is electrically connected between the inverting input terminal and the output terminal of the operational amplifier.

[0013] This application introduces the reference electrical signal and the sampling feedback signal into the operational amplifier in a symmetrical impedance manner through a differential symmetrical input resistor group in the differential input PI closed-loop error adjustment module. It also sets up a proportional-integral composite compensation network composed of a proportional feedback resistor R6, an integral series resistor R11, and an integral capacitor C3 connected in series. The differential input structure cancels out the common-mode components of the two signals, effectively suppressing common-mode noise such as power supply ripple and electromagnetic interference. The integral stage continuously accumulates and corrects the steady-state error until it is completely eliminated, solving the fundamental problem that the single proportional feedback scheme cannot eliminate steady-state deviation, and realizing high-precision error-free adjustment of the load current of the main power circuit.

[0014] As described above, in the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, optionally, the resistance values ​​of each differential input resistor in the differential symmetrical input resistor group are equal, and the resistance value of the non-inverting terminal grounding balancing resistor is equal to the resistance value of the differential input resistor, so as to make the equivalent input impedance of the two input terminals of the operational amplifier symmetrically matched and suppress the introduction of common-mode interference signals.

[0015] By setting the resistance values ​​of each differential input resistor in the differential symmetrical input resistor group to be equal, and making the resistance value of the grounding balancing resistor at the non-inverting input equal to the resistance value of the differential input resistor, the equivalent input impedances of the two input terminals of the operational amplifier are symmetrically matched. The common-mode signal generates the same voltage drop at both input terminals, and cancels each other out after differential operation, which significantly improves the common-mode rejection ratio of the circuit. This ensures the long-term consistency of signal integrity and closed-loop control accuracy in a strong electromagnetic interference environment under high current pulse conditions.

[0016] As described above, the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI can optionally include a complementary push-pull power drive output module comprising a pair of power transistors with complementary polarities, a drive input current-limiting resistor, and an emitter equalization current-limiting resistor; the pair of power transistors are an NPN power transistor and a PNP power transistor, respectively, forming a symmetrical push-pull amplification structure; wherein... The drive input current-limiting resistor is electrically connected between the output terminal of the differential input PI closed-loop error adjustment module and the base of the pair of power transistors; The emitter equalization current limiting resistors are electrically connected between the emitter and the drive output terminal of the NPN power transistor and the PNP power transistor, respectively.

[0017] This application employs NPN and PNP power transistors to form a symmetrical push-pull amplification structure in a complementary push-pull power drive output module. A drive input current-limiting resistor is placed between the base and the output of the preceding operational amplifier, and an emitter equalization current-limiting resistor is placed between the emitter of each power transistor and the drive output. This significantly improves the gate drive current capability, accelerates the IGBT gate charging and discharging speed, effectively eliminates the inherent crossover distortion of the push-pull structure, and the emitter equalization resistor simultaneously suppresses the risk of thermal runaway caused by device parameter dispersion. This enables the device to meet the wide range of high-current pulse drive requirements from 100A to 400A.

[0018] As described above, the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI can optionally include a pulse blocking device in the complementary push-pull power drive output module. This pulse blocking device is a high-speed switching diode connected in series in the drive output path of the complementary push-pull power drive output module, used to cut off the output path of the gate drive signal when the blocking control signal is effective. The anode of the high-speed switching diode is electrically connected to the emitter output terminal of the pair of power transistors, and its cathode is led out to the gate drive interface of the main power switching device.

[0019] By connecting a high-speed switching diode in series in the drive output path of the complementary push-pull power drive output module as a pulse blocking device, the anode of the diode is electrically connected to the emitter output terminal of the power transistor, and the cathode is led out to the gate drive interface of the main power switching device. When the blocking control signal is effective, the high-speed switching diode is reverse biased and cut off, which can cut off the gate drive signal output path within a nanosecond response time, preventing the main power switching device from being mis-connected when the equipment is abnormal, effectively protecting the safety of the power device, solving the technical problems of the lack of hardware-level drive blocking and the risk of damage to the power device in the event of a fault in the existing technology, and significantly improving the safety and reliability of the whole machine operation.

[0020] In the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI as described above, optionally, the sampling element is a high-precision sampling resistor, which is connected in series between the main power switching device and the load, and the resistance value of the high-precision sampling resistor is 1 to 10 mΩ.

[0021] By setting the sampling element to a high-precision sampling resistor with a resistance of 1 to 10 mΩ and connecting it in series between the main power switching device and the load, the milliohm-level low resistance design makes the voltage drop generated by the sampling resistor when a large current flows through it extremely small, and its impact on the power loss of the main power circuit is negligible. At the same time, it can accurately convert the load current of the main power circuit into a voltage signal that can be processed by the operational amplifier, realizing real-time accurate sampling of the load current and forming a signal source for high-precision current closed-loop feedback. Under the high current condition of 400A, the circuit power loss is only about 0.096 W, and the impact on the efficiency of the main power circuit is minimal.

[0022] As described above, in the high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, optionally, the power supply terminals of the precision operational amplifiers in the reference voltage reverse voltage amplification module and the sampling voltage proportional amplification module are both electrically connected to a dual power supply with positive and negative symmetry, and the positive and negative power supply terminals of the complementary push-pull power drive output module are both electrically connected to a composite filter network including electrolytic capacitors and film capacitors.

[0023] This application employs a symmetrical dual power supply (positive and negative) for the precision operational amplifiers in the reference voltage reverse voltage amplification module and the sampling voltage proportional amplification module. This enables the operational amplifiers to process analog signals of both positive and negative polarities, meeting the signal swing requirements of differential operations and ensuring that the operational amplifiers always operate within the linear range, thus avoiding output saturation distortion. The complementary push-pull power drive output module features a composite filter network composed of electrolytic capacitors and film capacitors at its positive and negative power supply terminals. The electrolytic capacitors filter out low-frequency ripple, while the film capacitors suppress high-frequency switching noise. The combined effect of these two components significantly reduces the interference of power drive stage power fluctuations on the preceding analog signal processing circuits, ensuring the stability of closed-loop control accuracy under full-range pulse conditions.

[0024] The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, as described above, may optionally include a PCB board, wherein the PCB board includes an analog signal layout area and a power drive layout area; wherein... The operational amplifiers and matching resistor-capacitor components in the reference voltage reverse voltage amplification module, the sampling voltage proportional amplification module, and the differential input PI closed-loop error adjustment module are located within the analog signal deployment area; The power transistor in the complementary push-pull power drive output module is located within the power drive deployment area. The analog signal routing area and the power drive routing area are isolated from each other on the PCB board.

[0025] By dividing the PCB into analog signal routing areas and power drive routing areas and isolating them from each other, the operational amplifiers and matching resistors and capacitors of the reference voltage reverse voltage amplification module, the sampling voltage proportional amplification module, and the differential input PI closed-loop error adjustment module are concentrated in the analog signal routing area, while the power transistors of the complementary push-pull power drive output module are concentrated in the power drive routing area. This physical layout suppresses the spatial coupling interference of the electromagnetic field generated by the high-current switching action on the millivolt-level sampling signal and the reference signal. The signal connectors and fixed terminals configured on the PCB respectively serve as modular signal interfaces and high-current mechanical connection functions, which facilitates the integration, installation and debugging of the whole machine and ensures the consistency of closed-loop control accuracy under full-range pulse conditions. Attached Figure Description

[0026] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein: Figure 1 A system structure block diagram of a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI provided by this utility model; Figure 2 A circuit schematic diagram of a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI provided in this application embodiment; Figure 3 A time-domain waveform diagram of the sampling current of the main power circuit under a 100A low-current operating condition is provided for an embodiment of this application. Figure 4 This application provides a time-domain waveform diagram of the sampling current of the main power circuit under a 400A high current condition. Detailed Implementation

[0027] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0028] From the perspective of traditional IGBT driver circuit architecture, open-loop fixed-value drive and single proportional feedback drive are the two most widely used solutions on the market. Open-loop drive architecture lacks a real-time current feedback link, and the output current depends entirely on the input reference voltage; even slight load fluctuations can cause significant deviations in the output amplitude. Single proportional feedback architecture relies solely on a single resistor for error amplification, lacking an integral correction branch, resulting in persistent steady-state current deviations after long-term system operation. Neither of these traditional solutions employs a differential input symmetrical impedance design, leading to impedance mismatch between the reference signal and the sampling feedback signal, which easily introduces common-mode interference, making it unsuitable for high-current pulse conditions exceeding 100A. In contrast, the PI closed-loop architecture with differential input and a composite RC integral compensation network can simultaneously achieve rapid dynamic error correction and complete elimination of steady-state error, making it the preferred hardware solution for solving the problem of high-current pulse output fluctuations.

[0029] From the perspective of specific equipment application scenarios, high-precision IGBT pulse drive circuits have irreplaceable application value in pulse load triggering devices and industrial pulse power sources. Real-world test results show that excessive fluctuations in the output current of the drive circuit can cause inconsistent light intensity of the pulse load, severe overheating of power devices, and increased equipment failure rates. However, the mainstream closed-loop drive circuits currently on the market have three major shortcomings: First, they only use a single operational amplifier to complete error calculations, lacking independent reference and sampling preamplifier units, making weak sampling signals easily submerged by noise; second, they lack a complementary push-pull power amplification structure, resulting in limited operational amplifier output current, slow IGBT gate charging and discharging speeds, and severe switching edge distortion; third, they lack a pulse hardware blocking branch, making it impossible to quickly cut off the drive signal in case of equipment failure, posing a risk of power transistor breakdown. Existing circuits cannot simultaneously meet the multiple requirements of wide current range, high steady-state accuracy, strong anti-interference, and rapid fault blocking, limiting the performance ceiling of high-precision pulse power equipment.

[0030] Based on this, this application provides a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI. Its core improvement lies in using dual independent precision operational amplifiers to pre-condition the reference voltage and current sampling voltage respectively. Through the coordinated cooperation of the differential input PI closed-loop error adjustment module and the complementary push-pull power drive output module, a wide-range, high-precision pulse constant current output is achieved, which solves the technical problems in the prior art such as reference signal temperature drift, large steady-state error, insufficient gate drive load capacity, and weak anti-interference ability.

[0031] Figure 1 This application provides a system structure block diagram of a high-precision push-pull IGBT pulse drive circuit device based on analog differential PI. (See diagram below.) Figure 1As shown, the device includes a reference voltage reverse voltage amplification module, a sampling voltage proportional amplification module, a differential input PI closed-loop error adjustment module, a complementary push-pull power drive output module, and a main power switching circuit. These modules are connected in series via signal lines to form a complete analog closed-loop control link.

[0032] The reference voltage inverting amplifier module receives a given reference voltage (usually a DC analog voltage signal, the amplitude range of which depends on the system design) from the external control system. It outputs a reference electrical signal, after inverting proportional amplification and impedance buffering, which is then fed into the non-inverting input of the differential input PI closed-loop error adjustment module. This module performs impedance isolation, amplitude scaling, and inversion processing on the external reference voltage, eliminating the influence of external signal source impedance variations on reference accuracy. Simultaneously, it utilizes the low-temperature drift characteristics of the precision operational amplifier to suppress amplitude drift of the reference signal caused by temperature changes.

[0033] The input of the sampling voltage proportional amplifier module is the current sampling voltage across the sampling element (high-precision sampling resistor) in the main power switching circuit. This signal is a weak voltage at the millivolt level, which comes directly from the main power circuit. The output is the sampling feedback signal after waveform shaping and amplitude matching, which is sent to the inverting input of the differential input PI closed-loop error adjustment module.

[0034] The extremely low amplitude current sampling voltage in the main power circuit is amplified to match the amplitude range of the reference electrical signal. At the same time, the sampling signal is filtered and shaped to eliminate the pollution of the sampling waveform by high current switching noise, ensuring that the differential input PI closed-loop error adjustment module obtains accurate and stable feedback.

[0035] The differential input PI closed-loop error adjustment module receives a reference electrical signal (connected to the non-inverting input) from the reference voltage reverse amplifier module and a sampling feedback signal (connected to the inverting input) from the sampling voltage proportional amplifier module. The two signals are introduced into the operational amplifier with symmetrical impedance. The output is the error control voltage after being corrected by the proportional-integral composite compensation network, which is sent to the base drive terminal of the complementary push-pull power drive output module.

[0036] The differential input structure cancels out the common-mode components of the two signals, effectively suppressing common-mode noise such as power supply ripple and electromagnetic interference. In the proportional-integral composite compensation network, the proportional element responds quickly to dynamic errors, while the integral element continuously accumulates and corrects steady-state errors until they are completely eliminated, achieving high-precision, error-free regulation of the load current in the main power circuit.

[0037] The input of the complementary push-pull power drive output module is the error control voltage from the output of the differential input PI closed-loop error adjustment module. After passing through the drive input current limiting resistor, it is connected to the base of the NPN and PNP power transistors. The output is the gate drive signal after current expansion and power amplification. It is led out from the emitter equalization current limiting resistor to the gate drive interface of the main power switching device (IGBT) to control the on and off of the IGBT.

[0038] The main power switching circuit consists of a main power switching device (IGBT), a load, and a sampling element connected in series to form a complete power path. The gate of the main power switching device receives the gate drive signal from the complementary push-pull power drive output module, and its collector-emitter path controls the on / off state of the load current. The voltage signal across the sampling element is output as a current feedback quantity to the sampling voltage proportional amplifier module, forming an analog closed-loop feedback link. The drive control signal is converted into the actual load current, and the current information is fed back to the front-end conditioning module through the sampling element, forming a complete current closed-loop control system that can achieve wide-range stable pulse constant current output without the need for a digital control chip.

[0039] The overall signal flow is as follows: the external reference voltage is processed by the reference voltage reverse voltage amplification module and output as a reference electrical signal; the load current of the main power circuit is converted into a sampling voltage by the sampling element, and then processed by the sampling voltage proportional amplification module to output a sampling feedback signal; the two signals are simultaneously input to the differential input PI closed-loop error adjustment module for differential calculation and PI correction; the corrected error control voltage drives the complementary push-pull power drive output module to generate a gate drive signal to control the IGBT switching, forming a complete closed loop. Through the coordinated operation of the above four modules and the main power switching circuit, this device achieves pure analog closed-loop constant current control, with a smooth output waveform, stable timing, and extremely low steady-state error under a wide range of pulse current conditions from 100A to 400A.

[0040] This application utilizes four modules—a reference voltage reverse voltage amplification module, a sampling voltage proportional amplification module, a differential input PI closed-loop error adjustment module, and a complementary push-pull power drive output module—to form a pure analog current closed-loop control system. This system eliminates the need for digital control chips and achieves high-precision constant current output under a wide pulse current range of 100A to 400A. Simultaneously, it addresses multiple technical issues such as reference signal temperature drift, large steady-state output deviation, insufficient gate drive load capacity, switch crossover oscillation, weak anti-interference capability, and lack of hardware-level fault protection. The output waveform is smooth, the timing is stable, and the steady-state error is extremely low.

[0041] Figure 2 This application provides a circuit schematic diagram of a high-precision push-pull IGBT pulse drive circuit based on analog differential PI. Figure 2As shown, the reference voltage inverting amplifier module includes a first precision operational amplifier (U1), an input current limiting resistor R2, a feedback amplification resistor R1, a non-inverting input balancing resistor R3, and filter capacitors C1 and C2.

[0042] The first precision operational amplifier receives an inverted input signal from the input current-limiting resistor R2 and a non-inverting reference potential grounded via the non-inverting balancing resistor R3 at its input terminal. The output terminal forms a closed negative feedback loop with the inverting input terminal through the feedback amplification resistor R1, and outputs the amplified reference electrical signal to the differential input PI closed-loop error adjustment module.

[0043] An inverting proportional amplifier topology is constructed using a first precision operational amplifier and resistors R1, R2 and R3 to provide impedance isolation and precise amplitude scaling for the external reference voltage. By utilizing the high open-loop gain and low input offset voltage characteristics of the precision operational amplifier, a low-drift and high-stability reference electrical signal is output.

[0044] The input terminal of the current-limiting resistor R2 receives an external reference voltage, and its output terminal is electrically connected to the inverting input terminal of the first precision operational amplifier. It limits the current flowing into the inverting input terminal of the operational amplifier to prevent damage to the operational amplifier input terminal due to sudden changes in the external signal source or overvoltage. Simultaneously, it, together with the feedback amplification resistor R1, determines the inverting amplification gain (gain = ...). R1 / R2).

[0045] For example, the resistance is 10kΩ; the resistance can be adjusted according to the actual reference voltage amplitude and target gain. Generally, a precision metal film resistor (accuracy ≤0.1%) in the range of 1kΩ to 100kΩ is selected to ensure gain accuracy.

[0046] The feedback amplification resistor R1 is connected between the inverting input and output of the first precision operational amplifier, forming a negative feedback loop; together with the input current limiting resistor R2, it sets the inverting amplification gain, with the absolute value of the gain being R1 / R2; at the same time, it determines the closed-loop output impedance of the operational amplifier, enabling the output to have low impedance drive capability.

[0047] For example, a resistance of 15 kΩ corresponds to an inverting gain of 1.5. In addition, the resistance value can be adjusted according to the actual gain requirements. It is recommended to use a precision metal film resistor with an accuracy of ≤0.1% to ensure that the gain error is minimized.

[0048] The balancing resistor R3 at the non-inverting input is connected between the non-inverting input of the first precision operational amplifier and ground, so that the equivalent DC impedances of the two inputs of the operational amplifier are symmetrically matched: the equivalent impedance of the non-inverting input is R3, and the equivalent impedance of the inverting input is approximately the parallel value of R1 and R2. When R3 = R1∥R2, the DC voltage drop generated by the bias current at both ends is equal and can cancel each other out, thereby eliminating the output DC deviation caused by the asymmetry of the bias current.

[0049] For example, the resistance is 8.2 kΩ (approximately equal to 15 kΩ∥10 kΩ = 6 kΩ, the closest standard value is taken in practice); in addition, the closest standard resistance value can be selected after accurately calculating the parallel equivalent value based on the actual resistance values ​​of R1 and R2.

[0050] Filter capacitors C1 and C2 are connected close to the positive and negative power supply pins of the first precision operational amplifier and ground to form a power supply decoupling network. This network suppresses high-frequency switching noise and low-frequency ripple on the power supply line from interfering with the operation of the operational amplifier and prevents power supply noise from coupling to the output through a path with limited power supply rejection ratio (PSRR), thus affecting the accuracy of the reference electrical signal.

[0051] For example, ceramic capacitors with a capacitance of 100nF are mounted close to the power supply pins; in addition, a composite decoupling network consisting of a 100nF ceramic capacitor and a 10μF tantalum capacitor in parallel can be used to suppress both high-frequency and low-frequency power supply interference; when wiring space is limited, only the 100nF ceramic capacitor can be retained as the basic decoupling.

[0052] For example, the first precision operational amplifier uses the OP27 low-drift precision operational amplifier, which has extremely low input offset voltage temperature drift (typically 0.2 μV / ℃), effectively suppressing amplitude drift of the reference signal caused by temperature changes. The input current-limiting resistor R2 has a resistance of 10 kΩ, the feedback amplification resistor R1 has a resistance of 15 kΩ, and the inverting amplification gain is 1.5 times; the non-inverting input balancing resistor R3 has a resistance of 8.2 kΩ; the filter capacitors C1 and C2 are both 100 nF; the first precision operational amplifier is powered by ±15V DC.

[0053] By setting a first precision operational amplifier, an input current-limiting resistor, a feedback amplification resistor, a non-inverting input balancing resistor, and a filter capacitor in the reference voltage inverting amplification module, an inverting proportional amplification topology is formed, achieving impedance isolation and precise amplitude scaling of the external reference voltage. The low temperature drift characteristic of the precision operational amplifier (typical value 0.2μV / ℃) effectively suppresses the amplitude drift of the reference signal caused by temperature changes. The non-inverting input balancing resistor R3 is matched with the equivalent impedance of the inverting input, eliminating the output DC deviation caused by bias current asymmetry. The filter capacitor decouples nearby, suppressing the influence of power supply ripple on the reference accuracy, and providing a low-drift, high-stability given reference value for the differential input PI closed-loop error adjustment module.

[0054] Continue as Figure 2 As shown, the sampling voltage proportional amplifier module includes a second precision operational amplifier (U2), a proportional feedback resistor R4, a non-inverting input balancing resistor R5, and filter capacitors C7 and C8.

[0055] The second precision operational amplifier, along with resistors R4 and R5, forms an inverting proportional amplifier topology. Its input receives a weak current sampling voltage from the sampling elements in the main power circuit (introduced to the inverting input via the input resistor), while the non-inverting input is grounded via the non-inverting balancing resistor R5. The output forms a negative feedback loop with the inverting input through the proportional feedback resistor R4, and outputs the amplified sampling feedback signal to the inverting input of the differential input PI closed-loop error adjustment module. For example, an OP27 precision operational amplifier is used, with a supply voltage of ±15V.

[0056] The proportional feedback resistor R4 is connected between the inverting input and output of the second precision operational amplifier. Together with the input resistor of the inverting input, it sets the proportional amplification gain of the sampling signal, thereby achieving amplitude range matching between the sampling voltage and the reference electrical signal. At the same time, it determines the closed-loop output impedance, ensuring that the output signal has low impedance driving capability.

[0057] For example, the resistance of R4 is 3 kΩ; in addition, the resistance value can be adjusted according to the actual sampling voltage amplitude and target gain requirements, and a precision metal film resistor with an accuracy of ≤0.1% can be selected to minimize gain error.

[0058] The non-inverting input balancing resistor R5 is connected between the non-inverting input of the second precision operational amplifier and ground. It is the same as the non-inverting input balancing resistor R3 in the reference voltage inverting amplifier module. It is used to balance the equivalent DC impedance of the two input terminals, eliminate the output DC deviation caused by bias current asymmetry, and improve the DC accuracy of the sampling feedback signal. For example, the resistance of R5 is 12kΩ. Alternatively, the closest standard value can be selected after accurately calculating the parallel equivalent value based on the actual input resistance and the resistance of R4.

[0059] Filter capacitors C7 and C8 are connected close to the positive and negative power supply pins of the second precision operational amplifier and ground, forming a power supply decoupling network. These are the same as the filter capacitors C1 and C2 in the reference voltage reverse voltage amplification module, used to suppress power supply ripple and high-frequency switching noise interference on the sampling amplification stage, ensuring the waveform integrity of the sampling feedback signal. For example, ceramic capacitors with a capacitance of 100nF are preferred; alternatively, a composite decoupling network of a 100nF ceramic capacitor and a 10μF tantalum capacitor in parallel can be used to enhance low-frequency ripple suppression.

[0060] Preferably, the second precision operational amplifier also uses an OP27 type precision operational amplifier with a supply voltage of ±15V. The proportional feedback resistor R4 has a resistance of 3 kΩ, and the non-inverting input balancing resistor R5 has a resistance of 12 kΩ; the filter capacitors C7 and C8 are both 100nF. The sampling voltage proportional amplification module performs amplitude adaptation and waveform shaping on the weak current sampling voltage across the sampling element in the main power circuit, matching it with the reference electrical signal in amplitude range. This ensures that the differential input PI closed-loop error adjustment module obtains an accurate error input signal, effectively solving the problem that weak sampling signals are easily overwhelmed by noise.

[0061] By setting a second precision operational amplifier, a proportional feedback resistor R4, a non-inverting input balancing resistor R5, and filter capacitors C7 and C8 in the sampling voltage proportional amplifier module, an inverting proportional amplifier topology is formed. This amplifies the millivolt-level weak current sampling voltage in the main power circuit to a level that matches the amplitude range of the reference electrical signal. The non-inverting input balancing resistor R5 eliminates the DC deviation caused by bias current asymmetry. The filter capacitors nearby decouple and filter out the pollution of the sampling waveform by high current switching noise, effectively solving the problem that weak sampling signals are easily submerged by noise, and ensuring that the differential input PI closed-loop error adjustment module obtains accurate and stable feedback.

[0062] Continue as Figure 2 As shown, the differential input PI closed-loop error adjustment module includes an operational amplifier (U3), a differential symmetrical input resistor group (including differential input resistors R8, R9, and R12), a non-inverting input grounding balancing resistor R7, a proportional feedback resistor R6, an integrating series resistor R11, and integrating capacitors C3 and C5. The functions of each component are as follows.

[0063] As the core component of the differential PI adjustment module, the operational amplifier receives the reference signal from the reference voltage inverting amplifier module through differential input resistors R8 and R9 at its inverting input terminal, and receives the sampling feedback signal from the sampling voltage proportional amplifier module through differential input resistor R12 at its non-inverting input terminal. The output terminal is fed back to the inverting input terminal through a proportional-integral composite compensation network (R6, R11, C3 in series), and outputs the error control voltage to the base drive terminal of the complementary push-pull power drive output module.

[0064] Differential calculations are performed on the reference electrical signal and the sampled feedback signal to extract the error between the two signals. After proportional-integral composite compensation, an error control voltage is output to drive the subsequent push-pull module to adjust the IGBT conduction level, so that the load current of the main power circuit tracks the reference set value. An OP27 precision operational amplifier is preferably used.

[0065] The differential symmetrical input resistor group includes three resistors (R8, R9, R12). R8 and R9 are connected in series in the path from the reference electrical signal to the inverting input of the operational amplifier, and R12 is connected in series in the path from the sampling feedback signal to the non-inverting input of the operational amplifier. The inputs are the reference electrical signal (R8 / R9 side) and the sampling feedback signal (R12 side), respectively, and the outputs are connected to the inverting input and non-inverting input of the operational amplifier, respectively.

[0066] By introducing the two signals into the operational amplifier with symmetrical impedance, the equivalent source impedances at the two input terminals are made equal, thus ensuring the symmetry of the differential operation and effectively suppressing the introduction of common-mode interference signals. Simultaneously, it provides a certain degree of low-pass filtering for the input signals, suppressing high-frequency noise. In the example, each resistance value is 100Ω; however, the resistance values ​​can be adjusted according to the signal source impedance and the required cutoff frequency. It is recommended to use precision resistors with an accuracy ≤0.1% to ensure strict symmetry between the two impedances.

[0067] The non-inverting input grounding balancing resistor R7 is connected between the non-inverting input of the operational amplifier and ground. It is connected in parallel with the differential input resistor R12 to form the equivalent grounding impedance of the non-inverting input. This impedance matches the equivalent impedance of the inverting input (R8∥R9∥R6), ensuring that the DC bias currents at both inputs produce equal voltage drops, canceling each other out and eliminating the output DC deviation caused by bias current asymmetry, thus improving the long-term DC accuracy of the closed-loop system. In the example, the resistance is 100Ω, equal to the differential input resistor; however, the matching value can be precisely calculated based on the equivalent impedance of the inverting input in the actual circuit and then selected.

[0068] The proportional feedback resistor R6 is connected between the inverting input and output of the operational amplifier. Together with the integrating series resistor R11 and the integrating capacitor C3, it forms a proportional-integral composite compensation network. Its input is the error control voltage at the operational amplifier output, and the output is fed back to the inverting input to form negative feedback. This feedback determines the system's proportional gain, rapidly generating a proportional adjustment component when an error signal is present, ensuring sufficient dynamic response speed. The proportional gain is determined by the ratio of R6 to the differential input resistor. For example, the resistance is 200Ω. Furthermore, the resistance value can be adjusted according to system bandwidth and stability requirements. A larger resistance value results in a higher proportional gain and faster response, but also a smaller stability margin, requiring comprehensive design considering integral parameters.

[0069] The integrating series resistor R11 and the integrating capacitor C3 are connected in series, and then in parallel with the proportional feedback resistor R6 to form a proportional-integral composite compensation network, which is connected between the inverting input and output of the operational amplifier. The input of the integrating capacitor C3 is the error current flowing through R11, and the output is the voltage accumulated over time, which is superimposed on the feedback network to form the integral compensation branch.

[0070] The integration time constant is determined by R11 × C3, affecting the integration speed and system stability. For example, R11 has a resistance of 200Ω and C3 has a capacitance of 4.7 nF. Furthermore, the product of R11 and C3 can be adjusted according to the system response speed requirements. For finer dynamic performance adjustment, the integrating capacitor can be replaced with an adjustable capacitor, or a small capacitor can be connected in parallel with R11 to increase high-frequency attenuation.

[0071] For example, the differential input resistors R8, R9, R12 and the non-inverting input grounding balancing resistor R7 are all 100Ω; the proportional feedback resistor R6 is 200Ω; the integrating series resistor R11 is 200Ω; the integrating capacitors C3 and C5 are both 4.7nF; the input filter capacitor C4 is 100nF; and the operational amplifier is an OP27 precision operational amplifier.

[0072] The differential input structure allows the reference electrical signal and the sampling feedback signal to be connected to the non-inverting and inverting inputs of the operational amplifier, respectively, and eliminates the common-mode interference components of the two signals through differential operation; the proportional-integral composite compensation network simultaneously eliminates dynamic deviation and steady-state error, realizing high-precision closed-loop constant current control of the load current of the main power circuit.

[0073] By employing a differential symmetrical input resistor group in the differential input PI closed-loop error adjustment module to introduce the reference electrical signal and the sampling feedback signal into the operational amplifier with symmetrical impedance, and setting up a proportional-integral composite compensation network consisting of a proportional feedback resistor R6, an integral series resistor R11, and an integral capacitor C3 connected in series, the differential input structure cancels out the common-mode components of the two signals, effectively suppressing common-mode noise such as power supply ripple and electromagnetic interference. The integral stage continuously accumulates and corrects the steady-state error until it is completely eliminated, solving the fundamental problem that the single proportional feedback scheme cannot eliminate steady-state deviation, and realizing high-precision error-free adjustment of the load current of the main power circuit.

[0074] In one implementation, the differential input resistors R8, R9, and R12 in the differential symmetrical input resistor group have equal resistance values, and the grounding balancing resistor R7 at the non-inverting input has the same resistance value as the differential input resistors, all set to 100Ω, to ensure symmetrical matching of the equivalent input impedances at the two input terminals of the operational amplifier. When the equivalent impedances at the two input terminals are perfectly symmetrical, the common-mode signal generates the same voltage drop at both input terminals, which cancels each other out after differential operation, thereby effectively suppressing common-mode interference and significantly improving the long-term consistency of signal integrity and closed-loop control accuracy of the circuit.

[0075] By setting the resistance values ​​of each differential input resistor in the differential symmetrical input resistor group to be equal, and making the resistance value of the grounding balancing resistor at the non-inverting input equal to the resistance value of the differential input resistor, the equivalent input impedances of the two input terminals of the operational amplifier are symmetrically matched. The common-mode signal generates the same voltage drop at both input terminals, and cancels each other out after differential operation, which significantly improves the common-mode rejection ratio of the circuit. This ensures the long-term consistency of signal integrity and closed-loop control accuracy in a strong electromagnetic interference environment under high current pulse conditions.

[0076] Continue as Figure 2 As shown, the complementary push-pull power drive output module includes a pair of power transistors (T1 and T2) with complementary polarities, a drive input current-limiting resistor, and an emitter equalization current-limiting resistor. The functions of each component are as follows.

[0077] NPN and PNP power transistors form a complementary pair. The bases of both transistors share a base drive current from the drive input current-limiting resistor. Their emitters are led out to the drive output terminal via equalizing current-limiting resistors R10 and R13, respectively. Their collectors are connected to the positive and negative power rails, respectively. The NPN power transistor is responsible for the current output (gate charging) during the positive half-cycle of the error control voltage; its input is the forward base current, and its output is the drive current flowing from the collector to the emitter. The PNP power transistor is responsible for the current absorption (gate discharging) during the negative half-cycle of the error control voltage; its input is the reverse base current, and its output is the absorption current flowing from the emitter to the collector.

[0078] The two transistors alternately conduct, forming a symmetrical push-pull amplification structure, which significantly improves the gate drive current capability, accelerates the gate charging and discharging speed of the IGBT, and eliminates the crossover distortion inherent in the push-pull structure. For example, the NPN power transistor uses TIP41 (collector current 6A, collector-emitter voltage 100V), and the PNP power transistor uses TIP42 (collector current 6A, collector-emitter voltage 100V), forming a complementary pair.

[0079] Alternatively, other complementary power transistor pairs with corresponding current and voltage ratings (such as BD243C / BD244C, MJE15003 / MJE15004, etc.) or complementary power MOSFET pairs (such as IRF530 / IRF9530) can be used instead. MOSFET drives have lower drive losses and faster switching speeds, but attention should be paid to matching their gate charge characteristics with the drive circuit.

[0080] The current-limiting resistor at the drive input is connected between the output of the differential input PI closed-loop error adjustment module and the base of the complementary pair transistors. Its input is the error control voltage from the output of the operational amplifier, and its output is the current-limited base drive current, which flows into the bases of the NPN and PNP transistors respectively. It limits the peak value of the drive current flowing into the base of the power transistor, preventing the output of the preceding operational amplifier from being overloaded and damaged due to excessive base drive current. At the same time, it plays a certain role in low-pass filtering of the drive signal and suppresses high-frequency oscillation.

[0081] For example, the resistance value is 100Ω; in addition, the resistance value can be adjusted according to the output current capability of the operational amplifier and the base current requirement of the power transistor, and is generally selected in the range of 47Ω to 220Ω; if a MOSFET pair is used to replace the transistor, this resistor also serves as a gate current limiting resistor, and the resistance value needs to be redesigned according to the MOSFET gate charge and allowable switching time.

[0082] Emitter equalization current limiting resistors (R10 and R13): R10 is connected between the emitter of the NPN power transistor and the drive output terminal, and R13 is connected between the emitter of the PNP power transistor and the drive output terminal. The input is the output current of the emitter of each power transistor, and the output is the gate drive current that is equalized and converged to the drive output terminal. Its functions are threefold: First, to balance the current distribution between the two transistors and suppress the risk of thermal runaway caused by the dispersion of device parameters (such as β value, Vbe); second, to introduce an appropriate emitter resistor voltage drop at the commutation moment when the two transistors alternately conduct, effectively eliminating the crossover distortion inherent in the push-pull structure and making the drive signal transition smoothly near the zero crossing point; and third, to provide a certain source impedance to the drive output terminal and suppress the reverse voltage spike caused by the Miller effect of the IGBT gate.

[0083] For example, the resistance values ​​of R10 and R13 are both 20Ω. In addition, the resistance values ​​can be adjusted according to the magnitude of the drive current and the crossover distortion suppression effect, and are generally selected in the range of 10Ω to 47Ω. If the resistance value is too large, it will reduce the drive current capability, and if it is too small, the crossover distortion suppression effect will be weakened. It is necessary to comprehensively weigh the actual IGBT gate charge parameters.

[0084] Preferably, the NPN power transistor is TIP41, and the PNP power transistor is TIP42, forming a complementary pair. The drive input current-limiting resistor has a resistance of 100Ω, and the emitter equalization current-limiting resistors R10 and R13 both have a resistance of 20Ω. The NPN power transistor is responsible for the current output during the positive half-cycle of the drive signal, and the PNP power transistor is responsible for the current absorption during the negative half-cycle of the drive signal. The two transistors alternately conduct to form a symmetrical push-pull amplification, which greatly improves the gate drive current capability, accelerates the charging and discharging speed of the IGBT gate, and enables this device to meet the needs of high-current pulse drive in a wide range from 100A to 400A.

[0085] This application employs NPN and PNP power transistors to form a symmetrical push-pull amplification structure in a complementary push-pull power drive output module. A drive input current-limiting resistor is placed between the base and the output of the preceding operational amplifier, and an emitter equalization current-limiting resistor is placed between the emitter of each power transistor and the drive output. This significantly improves the gate drive current capability, accelerates the IGBT gate charging and discharging speed, effectively eliminates the inherent crossover distortion of the push-pull structure, and the emitter equalization resistor simultaneously suppresses the risk of thermal runaway caused by device parameter dispersion. This enables the device to meet the wide range of high-current pulse drive requirements from 100A to 400A.

[0086] In one embodiment, the complementary push-pull power drive output module further includes a pulse blocking device D1, which is a high-speed switching diode. The high-speed switching diode D1 is connected in series in the drive output path of the complementary push-pull power drive output module and is used to cut off the output path of the gate drive signal when the blocking control signal is effective.

[0087] Specifically, the anode of the high-speed switching diode D1 is electrically connected to the emitter output terminal of the pair of power transistors, and its cathode is led out to the gate drive interface of the main power switching device. When the blocking control signal reverse-biases the high-speed switching diode D1, the drive output path is quickly cut off, which can cut off the gate drive signal in a very short time. The high-speed switching diode D1 has a nanosecond-level reverse recovery time, which can cut off the gate drive signal output path with a nanosecond-level response speed, preventing the main power switching device from being mis-connected when the equipment is abnormal, effectively protecting the safety of the power device, and solving the technical problems of the lack of hardware-level drive blocking and the risk of damage to the power device in the event of a fault in the prior art.

[0088] For example, the 1N4148 high-speed switching diode is used; in addition, other high-speed switching diodes with a reverse recovery time ≤10ns can also be used (such as BAV99, 1N914, etc.); in the case of needing a higher reverse blocking voltage, a high-voltage fast recovery diode (such as UF4007) can be selected; D1 can also be replaced with a small-signal MOSFET switch, and the on and off of the drive path can be achieved by controlling its gate potential, so as to obtain a lower forward voltage drop and a faster response speed.

[0089] In one implementation, the sampling element is a high-precision sampling resistor connected in series between the main power switching device and the load. The resistance of the high-precision sampling resistor is 1–10 mΩ. The milliohm-level low-resistance sampling resistor generates a very small voltage drop when a large current flows through it, and its impact on the power loss of the main power circuit is negligible. Simultaneously, it can accurately convert the load current into a voltage signal that can be processed by the operational amplifier, achieving real-time and accurate sampling of the load current of the main power circuit. For example, the resistance of the high-precision sampling resistor is 1.5 mΩ. Under a high current condition of 400 A, the sampling voltage generated across the 1.5 mΩ sampling resistor is 0.6 mV. After being amplified by the sampling voltage proportional amplifier module, it can reach the signal amplitude required for operational amplifier processing, while the circuit power loss is only 0.096 W, having a minimal impact on the efficiency of the main power circuit.

[0090] In one implementation, the precision operational amplifiers in both the reference voltage reverse amplification module and the sampling voltage proportional amplification module are powered by a symmetrical dual power supply. This symmetrical dual power supply enables the precision operational amplifiers to process analog signals of both positive and negative polarities, meeting the signal swing requirements of differential operations, while ensuring the operational amplifiers operate within the linear range and avoiding output saturation. The positive and negative power supply terminals of the complementary push-pull power drive output module are respectively equipped with a composite filter network consisting of electrolytic capacitors and film capacitors. The electrolytic capacitors are responsible for filtering out low-frequency power supply ripple, while the film capacitors are responsible for suppressing high-frequency switching noise. Their combined effect significantly reduces power supply interference from the power drive stage to the analog signal processing stage.

[0091] The positive and negative symmetrical dual power supply network takes an externally supplied positive and negative symmetrical DC power supply (e.g., ±15V) as input and outputs stable positive and negative supply voltages, which are respectively sent to the positive and negative power supply pins of each stage of the precision operational amplifier. This provides sufficient power supply swing for the operational amplifiers, enabling them to handle analog signals of both positive and negative polarities, ensuring normal operation of the operational amplifiers within their linear operating range, and avoiding signal cutoff distortion caused by a single power supply. For example, the supply voltage is ±15V, matching the recommended operating voltage range of the OP27 (±3V to ±18V).

[0092] A composite filter network (comprising electrolytic and film capacitors) is connected between the positive and negative power supply terminals and ground of the complementary push-pull power drive output module. The electrolytic capacitors receive low-frequency ripple from the power rails as input and output filtered, stable DC. The film capacitors receive high-frequency switching noise from the power rails as input and output clean power after suppressing high-frequency noise. Specifically, the electrolytic capacitors (large capacity, typically 10μF) store energy and filter low-frequency ripple, while the film capacitors (small capacity, typically 100nF) suppress high-frequency noise generated by the switching action of the power transistors. Their parallel operation significantly reduces the interference of power supply fluctuations in the power drive stage on the preceding analog signal processing circuitry, ensuring closed-loop control accuracy. For example, a composite filter network is configured with a 10μF electrolytic capacitor and a 100nF film capacitor at each of the positive and negative power supply terminals.

[0093] In one embodiment, the device further includes a PCB board, which is divided into an analog signal routing area and a power drive routing area. The operational amplifiers and matching resistors and capacitors in the reference voltage reverse voltage amplification module, the sampling voltage proportional amplification module, and the differential input PI closed-loop error adjustment module are mounted in the analog signal routing area. The power transistors in the complementary push-pull power drive output module are located in the power drive routing area. The analog signal routing area and the power drive routing area are isolated from each other on the PCB board to suppress electromagnetic coupling interference of the power drive signal to the analog small signal. The specific functions of each area are described below.

[0094] The analog signal deployment area houses all operational amplifiers and matching resistors and capacitors for the reference voltage reverse voltage amplification module, the sampling voltage proportional amplification module, and the differential input PI closed-loop error adjustment module. Its inputs are the external reference voltage signal and the weak sampling voltage signal from the main power circuit. The output is the error control voltage after conditioning and PI operation, which is transmitted to the power drive deployment area. It provides a low-noise, low-interference physical environment for the processing of weak analog signals. Through physical isolation from the power drive area, it reduces the spatial coupling interference of the electromagnetic field generated by the high-current switching action on the millivolt-level sampling signal and the reference signal, ensuring signal integrity.

[0095] The power drive deployment area is equipped with power transistors (TIP41 / TIP42) and their peripheral components of the complementary push-pull power drive output module, as well as the terminals of the main power switching circuit. Its input is the error control voltage from the analog signal deployment area, and its output is the gate drive signal after power amplification, which is transmitted to the IGBT gate drive interface. It carries high current switching action. Through physical isolation from the analog signal area, the electromagnetic interference generated by the switching of the power device is limited to the power drive area and prevented from spreading to the analog signal area.

[0096] For example, the PCB board uses an FR-4 double-layer printed circuit board, and the traces in the power drive area need to be widened to carry high current. In addition, the PCB board also features signal connectors and fixed terminals. The signal connectors take in reference input signals and pulse enable signals from external devices, and output drive signals to external devices. They provide modular signal interfaces for easy integration, installation, and debugging of the entire unit. The fixed terminals connect the external power supply line to the high-current wiring of the main power switch circuit, providing a reliable high-current mechanical connection to withstand current surges and vibrations under pulsed operating conditions.

[0097] like Figure 3 and Figure 4 The schematic diagrams show the time-domain waveforms of the sampling current of the main power circuit under two typical operating conditions: 100A (small current) and 400A (large current). This is to verify the closed-loop constant current regulation performance, pulse output consistency, steady-state control accuracy, and dynamic switching response characteristics of this device.

[0098] The first and second precision operational amplifiers in the above embodiments are not limited to the OP27 model. Depending on the actual application requirements, other low-drift precision operational amplifiers such as OP07, AD797, and LT1007 can also be used, as long as they meet the performance requirements of low input offset voltage and low temperature drift.

[0099] The NPN power transistor in the above embodiments is not limited to TIP41, and the PNP power transistor is not limited to TIP42. Other complementary power transistor pairs with corresponding current and voltage ratings can also be used, or complementary power MOSFET pairs can be used instead, as long as the IGBT gate drive current requirements can be met.

[0100] In the above embodiments, the resistance value of the high-precision sampling resistor is not limited to 1.5mΩ. It can be selected in the range of 1 to 10mΩ according to the actual circuit current range and the amplitude requirements of the sampling signal. The sampling element is not limited to the sampling resistor. In other embodiments, other current detection elements such as Hall current sensors can also be used, and their output signals can be connected to the sampling voltage proportional amplification module.

[0101] In the above embodiments, the PCB board is not limited to FR-4 double-layer printed circuit board. Multi-layer printed circuit boards or printed circuit boards with other substrates can also be used according to actual needs. The principle of physical isolation between the analog signal layout area and the power drive layout area should be maintained in all types of boards.

[0102] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0103] Based on the above description of this application, those skilled in the art will also understand that the following terms used, such as "upper," "lower," "length," "width," "top," "bottom," "inner," "outer," "axial," "longitudinal," "transverse," "clockwise," or "counterclockwise," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this application. They are only for the purpose of facilitating the explanation of the solution of this application and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as a limitation on the solution of this application.

[0104] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for convenience of description only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Also, a feature specified as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0105] While numerous embodiments of this application have been shown and described herein, it will be appreciated by those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise in the mind and spirit of this application without departing from its intent. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A high-precision push-pull IGBT pulse drive circuit device based on analog differential PI, comprising a main power switching circuit, characterized in that, Also includes: The reference voltage inverting amplifier module is used to receive an external reference voltage, perform inverting proportional amplification and impedance buffering on the reference voltage, and output a reference electrical signal. The sampling voltage proportional amplifier module is connected to the main power switch circuit signal and is used to receive the current sampling voltage across the sampling element in the main power switch circuit, perform waveform shaping and amplitude matching processing on the current sampling voltage, and output a sampling feedback signal. The differential input PI closed-loop error adjustment module is connected to the reference voltage reverse voltage amplification module and the sampling voltage proportional amplification module respectively. It is used to perform differential operation on the reference electrical signal and the sampling feedback signal, and output the error control voltage after being corrected by the proportional-integral composite compensation network. The complementary push-pull power drive output module is signal-connected to the differential input PI closed-loop error adjustment module. It is used to expand the current capacity and amplify the power of the error control voltage, generate a gate drive signal and output it to the main power switching circuit to control the on and off of the main power switching device. The main power switching circuit includes a main power switching device, a load, and a sampling element connected in series. The two ends of the sampling element are connected to the sampling voltage proportional amplifier module to form an analog closed-loop feedback link.

2. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The reference voltage inverting amplifier module includes a first precision operational amplifier, an input current-limiting resistor, a feedback amplification resistor, a non-inverting balancing resistor, and a filter capacitor; wherein... One end of the input current-limiting resistor receives an external reference voltage, and the other end is electrically connected to the inverting input terminal of the first precision operational amplifier. The feedback amplification resistor is electrically connected between the inverting input terminal and the output terminal of the first precision operational amplifier; The non-inverting input balancing resistor is electrically connected between the non-inverting input of the first precision operational amplifier and ground. The filter capacitor is electrically connected between the power supply pin of the first precision operational amplifier and ground.

3. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The sampling voltage proportional amplifier module includes a second precision operational amplifier, a proportional feedback resistor, a balancing resistor at the non-inverting input, and a filter capacitor; the second precision operational amplifier constitutes an inverting proportional amplifier topology; wherein... The proportional feedback resistor is electrically connected between the inverting input terminal and the output terminal of the second precision operational amplifier; The non-inverting input balancing resistor is electrically connected between the non-inverting input of the second precision operational amplifier and ground. The filter capacitor is electrically connected between the power supply pin of the second precision operational amplifier and ground.

4. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The differential input PI closed-loop error adjustment module includes an operational amplifier, a differential symmetrical input resistor group, a non-inverting input ground balancing resistor, a proportional feedback resistor, an integrator series resistor, and an integrator capacitor; wherein... The differential symmetrical input resistor group is electrically connected to the inverting input terminal and the non-inverting input terminal of the operational amplifier, respectively, and is used to introduce the reference electrical signal and the sampling feedback signal in a symmetrical impedance manner. The proportional feedback resistor, the integral series resistor, and the integral capacitor are connected in series to form a proportional-integral composite compensation network, which is electrically connected between the inverting input terminal and the output terminal of the operational amplifier.

5. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 4, characterized in that, The differential input resistors in the differential symmetrical input resistor group have equal resistance values, and the resistance value of the non-inverting terminal grounding balancing resistor is equal to the resistance value of the differential input resistor, so as to make the equivalent input impedance of the two input terminals of the operational amplifier symmetrically matched and suppress the introduction of common-mode interference signals.

6. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The complementary push-pull power drive output module includes a pair of power transistors with complementary polarities, a drive input current-limiting resistor, and an emitter equalization current-limiting resistor; the pair of power transistors are an NPN power transistor and a PNP power transistor, respectively, forming a symmetrical push-pull amplification structure; wherein... The drive input current-limiting resistor is electrically connected between the output terminal of the differential input PI closed-loop error adjustment module and the base of the pair of power transistors; The emitter equalization current limiting resistors are electrically connected between the emitter and the drive output terminal of the NPN power transistor and the PNP power transistor, respectively.

7. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 6, characterized in that, The complementary push-pull power drive output module also includes a pulse blocking device, which is a high-speed switching diode connected in series in the drive output path of the complementary push-pull power drive output module. This high-speed switching diode is used to cut off the output path of the gate drive signal when the blocking control signal is valid. The anode of the high-speed switching diode is electrically connected to the emitter output terminal of the pair of power transistors, and its cathode is led out to the gate drive interface of the main power switching device.

8. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The sampling element is a high-precision sampling resistor, which is connected in series between the main power switching device and the load, and the resistance value of the high-precision sampling resistor is 1 to 10 mΩ.

9. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, The power supply terminals of the precision operational amplifier in the reference voltage reverse voltage amplification module and the sampling voltage proportional amplification module are both electrically connected to a dual power supply with positive and negative symmetry. The positive and negative power supply terminals of the complementary push-pull power drive output module are both electrically connected to a composite filter network including electrolytic capacitors and film capacitors.

10. The high-precision push-pull IGBT pulse drive circuit device based on analog differential PI according to claim 1, characterized in that, It also includes a PCB board, which comprises an analog signal routing area and a power drive routing area; wherein, The operational amplifiers and matching resistor-capacitor components in the reference voltage reverse voltage amplification module, the sampling voltage proportional amplification module, and the differential input PI closed-loop error adjustment module are located within the analog signal deployment area; The power transistor in the complementary push-pull power drive output module is located within the power drive deployment area. The analog signal routing area and the power drive routing area are isolated from each other on the PCB board.

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